US20230383822A1 - Helical drive mechanism and handle mechanism for wheelchair with helical drive - Google Patents
Helical drive mechanism and handle mechanism for wheelchair with helical drive Download PDFInfo
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- US20230383822A1 US20230383822A1 US18/305,179 US202318305179A US2023383822A1 US 20230383822 A1 US20230383822 A1 US 20230383822A1 US 202318305179 A US202318305179 A US 202318305179A US 2023383822 A1 US2023383822 A1 US 2023383822A1
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Images
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
- A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
- A61G5/02—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs propelled by the patient or disabled person
- A61G5/024—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs propelled by the patient or disabled person having particular operating means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
- F16H25/08—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for interconverting rotary motion and reciprocating motion
- F16H25/12—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for interconverting rotary motion and reciprocating motion with reciprocation along the axis of rotation, e.g. gearings with helical grooves and automatic reversal or cams
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
- A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
- A61G5/02—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs propelled by the patient or disabled person
- A61G5/021—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs propelled by the patient or disabled person having particular propulsion mechanisms
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
- A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
- A61G5/02—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs propelled by the patient or disabled person
- A61G5/021—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs propelled by the patient or disabled person having particular propulsion mechanisms
- A61G5/023—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs propelled by the patient or disabled person having particular propulsion mechanisms acting directly on hubs or axis
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
- A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
- A61G5/02—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs propelled by the patient or disabled person
- A61G5/024—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs propelled by the patient or disabled person having particular operating means
- A61G5/025—Levers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H1/00—Toothed gearings for conveying rotary motion
- F16H1/02—Toothed gearings for conveying rotary motion without gears having orbital motion
- F16H1/04—Toothed gearings for conveying rotary motion without gears having orbital motion involving only two intermeshing members
- F16H1/06—Toothed gearings for conveying rotary motion without gears having orbital motion involving only two intermeshing members with parallel axes
- F16H1/08—Toothed gearings for conveying rotary motion without gears having orbital motion involving only two intermeshing members with parallel axes the members having helical, herringbone, or like teeth
Definitions
- the field of invention relates to human-powered drive mechanisms. More particularly, the field of invention relates to control mechanisms for human-powered drive mechanisms that are operable to convert a linear input force to a helical drive torque through the use of a helical element.
- Vehicles and other human-powered devices that are driven by a rotational drive torque are known.
- such devices are inefficient and require the application of human input power in a manner that may not be biomechanically desirable.
- FIG. 1 A shows a perspective view of a first exemplary embodiment of a helical drive
- FIG. 1 B shows a side view of the helical drive of FIG. 1 A ;
- FIG. 1 C shows a top view of the helical drive of FIG. 1 A ;
- FIG. 1 D shows a front view of the helical drive of FIG. 1 A ;
- FIG. 2 A shows a perspective view of a helical member of the helical drive of FIG. 1 A ;
- FIG. 2 B shows a side view of the helical member of FIG. 2 A ;
- FIG. 2 C shows a front view of the helical member of FIG. 2 A ;
- FIG. 3 A shows a perspective view of an actuator handle of the helical drive of FIG. 1 A ;
- FIG. 3 B shows a side view of the actuator handle of FIG. 3 A ;
- FIG. 3 C shows a top view of the actuator handle of FIG. 3 A ;
- FIG. 4 A shows a perspective view of a frame of the helical drive of FIG. 1 A ;
- FIG. 4 B shows a side view of the frame of FIG. 4 A ;
- FIG. 4 C shows a top view of the frame of FIG. 4 A ;
- FIG. 4 D shows a front view of the frame of FIG. 4 A ;
- FIG. 5 A shows a perspective view of a subassembly including the actuator handle of FIG. 3 A and the frame of FIG. 4 A ;
- FIG. 5 B shows a side view of the subassembly of FIG. 5 A ;
- FIG. 5 C shows a top view of the subassembly of FIG. 5 A ;
- FIG. 5 D shows a front view of the subassembly of FIG. 5 A ;
- FIG. 6 A shows a perspective view of a second exemplary embodiment of a helical drive
- FIG. 6 B shows a side view of the helical drive of FIG. 6 A ;
- FIG. 6 C shows a top view of the helical drive of FIG. 6 A ;
- FIG. 6 D shows a front view of the helical drive of FIG. 6 A ;
- FIG. 7 A shows a perspective view of a helical member of the helical drive of FIG. 6 A ;
- FIG. 7 B shows a side view of the helical member of FIG. 7 A ;
- FIG. 7 C shows a front view of the helical member of FIG. 7 A ;
- FIG. 8 A shows a perspective view of an actuator handle of the helical drive of FIG. 6 A ;
- FIG. 8 B shows a side view of the actuator handle of FIG. 8 A ;
- FIG. 8 C shows a front view of the actuator handle of FIG. 8 A ;
- FIG. 8 D shows a top view of the actuator handle of FIG. 8 A ;
- FIG. 9 A shows a perspective view of a frame of the helical drive of FIG. 6 A ;
- FIG. 9 B shows a side view of the frame of FIG. 9 A ;
- FIG. 9 C shows a top view of the frame of FIG. 9 A ;
- FIG. 9 D shows a front view of the frame of FIG. 9 A ;
- FIG. 10 A shows a perspective view of a subassembly including the actuator handle of FIG. 8 A and the frame of FIG. 9 A ;
- FIG. 10 B shows a side view of the subassembly of FIG. 10 A ;
- FIG. 10 C shows a top view of the subassembly of FIG. 10 A ;
- FIG. 10 D shows a front view of the subassembly of FIG. 10 A ;
- FIG. 11 shows a perspective view of a helical drive system including the helical drive of FIG. 1 A ;
- FIG. 12 shows a side view of a representative helical section
- FIG. 13 shows a cross-sectional view of a representative helical section
- FIG. 14 shows a graph of torque and frictional force against applied force for a helical drive
- FIG. 15 shows a graph of efficiency against applied force for a helical drive
- FIG. 16 shows graphs of torque and efficiency against pitch diameter for a helical drive
- FIG. 17 shows graphs of torque and efficiency against lead angle for a helical drive
- FIG. 18 shows a first subset of selected elements of a helical drive system including the helical drive of FIG. 1 A ;
- FIG. 19 shows a second subset of selected elements of a helical drive system including the helical drive of FIG. 1 A ;
- FIG. 20 shows a first subset of selected elements of a helical drive system including the helical drive of FIG. 6 A ;
- FIG. 21 shows a second subset of selected elements of a helical drive system including the helical drive of FIG. 6 A .
- FIG. 22 shows a perspective view of a third exemplary embodiment of a helical drive
- FIG. 23 shows a section view of a control system of the helical drive of FIG. 22 ;
- FIG. 24 shows an exploded view of a handle assembly of the helical drive of FIG. 22 ;
- FIG. 25 A shows a perspective view of a housing of the helical drive of FIG. 22 ;
- FIG. 25 B shows a section view of the housing of FIG. 25 A ;
- FIG. 26 shows a perspective view of a bearing housing of the helical drive of FIG. 22 ;
- FIG. 27 shows a perspective view of a bearing control sleeve of the helical drive of FIG. 22 ;
- FIG. 28 shows a perspective view of a helical sleeve of the helical drive of FIG. 22 ;
- FIG. 29 shows a perspective view of a one-way bearing of the helical drive of FIG. 22 ;
- FIG. 30 shows a perspective view of a spacer of the helical drive of FIG. 22 ;
- FIG. 31 shows a perspective view of a helical member of the helical drive of FIG. 22 ;
- FIG. 32 shows a perspective view of a first end housing of the helical drive of FIG. 22 ;
- FIG. 33 shows a perspective view of an end bearing of the helical drive of FIG. 22 ;
- FIG. 34 shows a perspective view of a second end housing of the helical drive of FIG. 22 ;
- FIG. 35 shows a perspective view of a bevel gear of the helical drive of FIG. 22 ;
- FIG. 36 shows a perspective view of a slider rod of the helical drive of FIG. 22 ;
- FIG. 37 shows a section view of the control system of FIG. 23 , a handle assembly having been actuated to position the control system in a “forward” configuration
- FIG. 38 shows a section view of the control system of FIG. 23 , a handle assembly having been actuated to position the control system in a “reverse” configuration.
- the exemplary embodiments relate to a helical drive suitable for use in human-powered vehicles and similar devices, and operable to receive linear force and motion as an input and provide torque as an output.
- a helical drive in an embodiment, includes a frame, a handle actuator attached to the frame and slidaby movable along the frame along a linear axis, and a helical member positioned within the frame and rotatably movable within the frame about a longitudinal axis parallel to the linear axis, whereby motion of the handle actuator along the linear axis causes corresponding rotation of the helical member about the longitudinal axis.
- the helical drive includes at least one follower bearing positioned on a portion of the handle actuator so as to reduce friction between the handle actuator and the helical member.
- the helical drive includes at least one plain bearing positioned on a portion of the frame so as to reduce friction between the helical member and the frame.
- the helical member has a helical pitch of between 85 millimeters and 95 millimeters.
- the helical member has a lead angle of between 24 degrees and 27 degrees.
- the helical member has a pitch diameter of between 48 millimeters and 52 millimeters.
- a helical drive system includes a helical drive, a flexible drive shaft, and a freewheel
- the helical drive includes a frame, a handle actuator attached to the frame and slidaby movable along the frame along a linear axis, and a helical member positioned within the frame and rotatably movable within the frame about a longitudinal axis parallel to the linear axis, whereby motion of the handle actuator along the linear axis causes corresponding rotation of the helical member about the longitudinal axis
- the flexible drive shaft is coupled to the helical member such that rotation of the helical member causes corresponding rotation of the flexible drive shaft, and wherein the flexible drive shaft is coupled to the freewheel.
- the helical drive includes at least one follower bearing positioned on a portion of the handle actuator so as to reduce friction between the handle actuator and the helical member. In some embodiments, the helical drive includes at least one plain bearing positioned on a portion of the frame so as to reduce friction between the helical member and the frame. In some embodiments, the helical member has a helical pitch of between 85 millimeters and 95 millimeters. In some embodiments, the helical member has a lead angle of between 24 degrees and 27 degrees. In some embodiments, the helical member has a pitch diameter of between 48 millimeters and 52 millimeters.
- a helical drive system includes a control system, the control system including a handle assembly that is operable to selectively position the control system in a “neutral” position, a “forward” position, or a “reverse” position.
- the helical drive system includes a helical member having at least one helical depression formed therein.
- the control system includes a sleeve surrounding the helical member, the sleeve having at least one internal thread engaging the at least one helical depression of the helical member.
- the control system includes at least a first one-way bearing and a second one-way configured to selectively engage the sleeve, wherein, when the first one-way bearing is engaged to the sleeve, the first one-way bearing allows the sleeve to rotate with respect to the helical member in a first direction and prevents the sleeve from rotating with respect to the helical member in a second direction that is opposite the first direction, and wherein, when the second one-way bearing is engaged to the sleeve, the second one-way bearing allows the sleeve to rotate with respect to the helical member in the second direction and prevents the sleeve from rotating with respect to the helical member in the first direction.
- a helical drive includes a helical member having a longitudinal axis, a frame containing the helical member, and a handle actuator movable along the frame in a direction parallel to the longitudinal axis of the helical member, thereby to induce the helical to rotate about its longitudinal axis.
- a helical drive includes a “positive” or “open” helical form to allow a rigid member to actuate the helical as the user applies a linear force along the primary axis of the drive, and a simple frame is used to provide a guide for the handle actuator, provide stability for the cylindrical elements of the drive, and housing surfaces for the plain bearings.
- a helical drive includes a handle actuator, at least one follower bearing, a frame, an end cap, at least one plane bearing, an output shaft, and a helical member.
- a helical drive includes a “negative” or “solid” helical form including a helical path cut into a helical drive member.
- a helical drive includes a surrounding cuff to support follower bearings.
- the follower bearings make contact with the helical path cut into the drive member.
- the force is applied to the helical path through the followers, thereby rotating the helical member and, in turn, the output shaft.
- a simple frame is used to provide a guide for the handle, to provide stability for the cylindrical elements of the drive, and to provide housing surfaces for the plain bearings, while a secondary cuff provides support for the follower bearings.
- FIGS. 1 A- 1 D show an exemplary helical drive 100 that includes a “positive” or “open” helical form from various view angles.
- FIG. 1 A shows a perspective view
- FIG. 1 B shows a side view
- FIG. 1 C shows a top view
- FIG. 1 D shows a front view.
- FIGS. 2 A- 2 C shows an exemplary helical member 200 of the helical drive 100 of FIGS. 1 A- 1 D .
- FIG. 2 A shows a perspective view
- FIG. 2 B shows a side view
- FIG. 2 C shows a front view.
- the helical member 200 includes a helical channel 202 extending along and around substantially the entire length thereof.
- the exemplary helical member 200 is provided with a drive end cap 210 and a retention end cap 220 , which are fixed to opposing ends of the helical member 200 such that an essentially inseparable whole is formed.
- the drive end cap 210 and the retention end cap 220 are fixed to the helical member 200 by rivets.
- the drive end cap 210 is configured to provide output torque, such as to a drive shaft.
- the helical member 200 is made of formed stainless steel.
- the helical member 200 is made of a chromium-nickel stainless steel alloy.
- the helical member 200 is made of type 301 stainless steel.
- the helical member 200 is made from a cold-rolled bead-blasted stainless steel.
- the helical member 200 is formed using a three-axis CNC helical forming machine.
- the helical member 200 is formed using a helix forming machine such as those commercialized by Helix Flight Manufacturing Machines of Auckland, New Zealand.
- the helical member 200 is formed using a spring forming machine.
- FIGS. 3 A- 3 C show an exemplary handle actuator 300 of the helical drive 100 of FIGS. 1 A- 1 D .
- FIG. 3 A shows a perspective view
- FIG. 3 B shows a side view
- FIG. 3 C shows a top view.
- the handle actuator 300 includes recesses 310 and 320 that are sized and shaped to receive follower bearings, which will be described in further detail hereinafter.
- the handle actuator 300 is made from an aluminum alloy.
- the handle actuator 300 is made by a stamping process.
- the handle actuator 300 is made from an alloy including aluminum, magnesium, and silicon, such as 6061 aluminum.
- FIGS. 4 A- 4 D show an exemplary frame 400 of the helical drive 100 of FIGS. 1 A- 1 D .
- FIG. 4 A shows a perspective view
- FIG. 4 B shows a side view
- FIG. 4 C shows a top view
- FIG. 4 D shows a front view.
- the frame 400 includes a top slot 410 and a bottom slot 420 (collectively “the slots 410 , 420 ”) that are sized and shaped to receive the handle actuator 300 therein in a manner such that the handle actuator 300 is free to move along the frame 400 along an allowable travel defined by the length of the top slot 410 and the bottom slot 420 .
- the frame 400 includes a drive end hole 430 and a retention end hole 440 , which are configured to receive the drive end cap 210 and the retention end cap 220 , respectively, of the helical member 200 , thereby to retain the helical member 200 within the frame 400 and to allow the helical member 200 to rotate along its longitudinal axis with respect to the frame 400 .
- FIGS. 5 A- 5 D show an exemplary partially assembled view of the frame 400 and the handle actuator 300 .
- FIG. 5 A shows a perspective view
- FIG. 5 B shows a side view
- FIG. 5 C shows a top view
- FIG. 5 D shows a front view.
- the frame 400 is made from an aluminum alloy.
- the frame 400 is made by a stamping process.
- the frame 400 is made from an alloy including aluminum, magnesium, and silicon, such as 6061 aluminum.
- the helical drive 100 includes plain bearings 110 and 120 that are positioned within the drive end hole 430 and the retention end hole 440 , respectively, of the frame 400 , and about the drive end cap 210 and the retention end cap 220 , respectively, of the helical member 200 , thereby to reduce rotational friction when the helical member 200 rotates about its longitudinal axis.
- the helical drive 100 also includes follower bearings 130 and 140 that are positioned within the recesses 310 and 320 , respectively, of the handle actuator 300 , thereby to reduce friction when the handle actuator 300 moves along the slots 410 , 420 of the frame 400 to drive rotational motion of the helical member 200 .
- At least one of the plain bearings 110 and 120 is a bearing such as the bearings commercialized by Igus Inc. of East Buffalo, Rhode Island under the trade name IGLIDE.
- at least one of the plain bearings 110 , 120 and/or at least one of the follower bearings 130 , 140 includes a tape liner such as the liner commercialized by Igus Inc. of East Buffalo, Rhode Island under the trade name IGLIDUR.
- FIGS. 6 A- 6 D show various views of an exemplary helical drive 600 that includes a “negative” or “solid” helical form.
- FIG. 6 A shows a perspective view
- FIG. 6 B shows a side view
- FIG. 6 C shows a top view
- FIG. 6 D shows a front view.
- FIGS. 7 A- 7 C shows an exemplary helical member 700 of the helical drive 600 of FIGS. 6 A- 6 D .
- FIG. 7 A shows a perspective view
- FIG. 7 B shows a side view
- FIG. 7 C shows a front view.
- the helical member 700 includes a helical channel 702 extending along and around substantially the entire length thereof.
- the exemplary helical member 700 is provided with a drive end cap 710 and a retention end cap 720 , which are fixed to opposing ends of the helical member 700 such that an essentially inseparable whole is formed.
- the drive end cap 710 and the retention end cap 720 are fixed to the helical member 700 by rivets.
- the drive end cap 710 is configured to provide output torque, such as to a drive shaft.
- the helical member 700 is made of formed stainless steel.
- the helical member 700 is made of a chromium-nickel stainless steel alloy.
- the helical member 700 is made of type 301 stainless steel.
- the helical member 700 is made from a cold-rolled bead-blasted stainless steel.
- the helical member 700 is formed using a three-axis CNC helical forming machine.
- the helical member 700 is formed using a helix forming machine such as those commercialized by Helix Flight Manufacturing Machines of Auckland, New Zealand.
- the helical member 700 is formed using a spring forming machine.
- FIGS. 8 A- 8 C show an exemplary handle actuator 800 of the helical drive 600 of FIGS. 6 A- 6 D .
- FIG. 8 A shows a perspective view
- FIG. 8 B shows a side view
- FIG. 8 C shows a front view
- FIG. 8 D shows a top view.
- the handle actuator 800 includes a handle portion 810 , a frame portion 820 , and prongs 830 and 840 extending from the frame portion 820 that are sized and shaped to receive follower bearings, which will be described in further detail hereinafter.
- the handle actuator 800 is made from an aluminum alloy.
- the handle actuator 800 is made by a stamping process.
- the handle actuator 800 is made from an alloy including aluminum, magnesium, and silicon, such as 6061 aluminum.
- FIGS. 9 A- 9 D show an exemplary frame 900 of the helical drive 600 of FIGS. 6 A- 6 D .
- FIG. 9 A shows a perspective view
- FIG. 9 B shows a side view
- FIG. 9 C shows a top view
- FIG. 9 D shows a front view.
- the frame 400 is sized and shaped to be received within the frame portion 820 of the handle actuator 800 (see, e.g., FIG. 10 A ) such that the handle actuator 800 can move along the frame 800 .
- the frame 800 includes a top slot 810 and a bottom slot 820 (collectively “the slots 810 , 820 ”) that are sized and shaped to receive the prongs 830 and 840 of the handle actuator 800 therein in a manner such that the handle actuator 800 is free to move along the frame 900 along an allowable travel defined by the length of the top slot 910 and the bottom slot 920 .
- the frame 900 includes a drive end hole 930 and a retention end hole 940 , which are configured to receive the drive end cap 710 and the retention end cap 720 , respectively, of the helical member 700 , thereby to retain the helical member 700 within the frame 900 and to allow the helical member 700 to rotate along its longitudinal axis with respect to the frame 900 .
- FIG. 10 A shows a perspective view
- FIG. 10 B shows a side view
- FIG. 10 C shows a top view
- FIG. 10 D shows a front view.
- the frame 900 is made from an aluminum alloy.
- the frame 900 is made by a stamping process.
- the frame 900 is made from an alloy including aluminum, magnesium, and silicon, such as 6061 aluminum.
- the helical drive 600 includes plain bearings 610 and 620 that are positioned within the drive end hole 930 and the retention end hole 940 , respectively, of the frame 900 , and about the drive end cap 710 and the retention end cap 720 , respectively, of the helical member 700 , thereby to reduce rotational friction when the helical member 700 rotates about its longitudinal axis.
- the helical drive 600 also includes follower bearings 630 and 640 (see FIG.
- At least one of the plain bearings 610 and 620 is a bearing such as the bearings commercialized by Igus Inc. of East Buffalo, Rhode Island under the trade name IGLIDE.
- at least one of the plain bearings 610 , 620 and/or at least one of the follower bearings 630 , 640 includes a tape liner such as the liner commercialized by Igus Inc. of East Buffalo, Rhode Island under the trade name IGLIDUR.
- FIG. 11 shows a perspective view of a helical drive system 1100 .
- the helical drive system 1100 includes the helical drive 100 described above with reference to FIGS. 1 A- 5 D .
- the helical drive system 1100 may include a different helical drive such as the helical drive 600 described above with reference to FIGS. 6 A- 10 D .
- the helical drive 100 is secured to a structural element 1110 (e.g., a structural member of a vehicle that is to be driven by the helical drive 100 ).
- the helical drive 100 is secured to the structural element 1110 by a clamp 1120 .
- the helical drive 100 may be secured to the structural element 1110 by any other suitable fastening mechanism known in the art. It will also be apparent to those of skill in the art that the helical drive 100 need not be secured to the structural element 1110 by the clamp 1120 or other fastening mechanism located at the specific location of the frame 400 shown in FIG. 11 , and may be secured to the structural element 1110 at any other position along the frame 400 of the helical drive 100 .
- the helical drive system 1100 also includes a flexible output shaft 1130 having a first end 1132 and a second end 1134 opposite the first end 1132 .
- the flexible shaft 1130 is a flexible shaft that is capable of transmitting rotary motions/torques while bent around a desired path.
- the flexible shaft 1130 is capable of rotation at speeds of up to 10,000 rpm.
- the flexible shaft 1130 has a circular cross-section.
- the flexible shaft 1130 has a diameter of 0.25 inches.
- the flexible shaft 1130 is capable of transmitting an applied torque of up to 110 inch-pounds.
- the flexible shaft 1130 is made from a steel alloy.
- the flexible shaft 1130 is capable of performing as described above while flexed to a bend radius of 5 inches or more.
- the flexible shaft 1130 is similar to the flexible shafts commercialized the McMaster-Carr Supply Company of Elmhurst, Illinois as part number 3787.
- the first end 1132 of the flexible shaft 1130 is secured to the drive end cap 210 of the helical member 200 of the helical drive 100 by a set screw connection, thereby to transmit torque from the helical member 200 to the first end 1132 of the flexible shaft 1130 and along the flexible shaft 1130 to the second end 1134 thereof.
- the helical drive system 1100 includes a freewheel 1140 .
- a freewheel is a transmission device that disengages a driveshaft (e.g., the flexible shaft 1130 ) from a driven shaft (e.g., a downstream component of a drive train that is driven by the driveshaft) when the driven shaft rotates faster than the driveshaft.
- a driveshaft e.g., the flexible shaft 1130
- a driven shaft e.g., a downstream component of a drive train that is driven by the driveshaft
- such disengagement occurs, for example, when the driven shaft is rotating in a first direction (e.g., a direction that propels a vehicle in a primary travel direction) and the driveshaft is rotated in a second direction opposite the first direction.
- the freewheel 1140 is similar to the freewheel commercialized by Shimano, Inc. of Sakai, Japan under the trade name RM33.
- the freewheel 1140 includes a first side 1142 that is coupled to the flexible shaft 1130 and a second side 1144 opposite the first side 1142 .
- the helical drive system 1100 includes a hub 1150 .
- the hub 1150 is the hub of a wheel to be driven by the helical drive system 1100 , thereby to drive a vehicle.
- the hub 1150 drives a vehicle or other device to be driven by the helical drive system in a manner commensurate with the operation of the vehicle or other device.
- the hub 1150 is coupled to the second side 1144 of the freewheel 1140 .
- the torque generated by the helical drive 100 or 600 results from the application of a force at a distance from the center of the drive shaft.
- the torque is the product of the orthogonal applied force and the distance from the center of the shaft.
- FIG. 12 shows a side view of a representative helical section, wherein r represents the radius, D p represents the pitch diameter, and L represents the lead.
- FIG. 13 shows a cross-section of a helical section to illustrate torque, wherein F o represents the orthogonal force and r represents the radius.
- the orthogonal component of the force can be understood by “unravelling” one pitch (e.g., rotation) of the helical path into an incline plane relationship.
- the follower bearing can be understood to be working against the plane to develop the orthogonal force F o .
- a number of other forces arrive, including the frictional force F F .
- the forces also include the normal force F N , the vertical component of which will act as “thrust” along the axis of the bearing and may be considered when selecting the bearings.
- T F ⁇ d ( 1 )
- T F ⁇ ⁇ D p 2 [ L + ⁇ ⁇ fD P ⁇ ⁇ Dp - fL ]
- c FL 2 ⁇ ⁇ ⁇ T ( 4 )
- Equation (1) is the standard definition of torque, and is used to translate the orthogonal force into torque delivered at the shaft output.
- Equation (3) translates the applied downward force Fa into the component Fo and further into the applied torque about the central axis of the drive via Equation (1), where r is half of the pitch diameter.
- Efficiency of the drive output which can be understood to equal the ratio of actual torque output with frictional losses to ideal torque output without frictional losses, is calculated via Equation (4) above.
- FIG. 14 shows graphs of torque and frictional force against applied force for a helical drive including a 50 mm pitch diameter and a helical pitch of 80 mm (which correspond to a lead angle of 27 degrees). It may be seen that there is a linear relationship between torque and applied force, and that increased force results in increased torque with no particular local maxima. It may also be seen that there is a linear relationship between frictional force and applied force.
- FIG. 15 shows a graph of efficiency against applied force for a helical drive having dimensions as noted above. It may be seen that there is a precipitous drop in efficiency between 0 and 200 N and a gradual decline thereafter. In some embodiments, this may suggest that greater efficiency is achieved with applied forces below the average possible from a given user.
- FIG. 16 shows graphs of torque and efficiency for varying values of pitch diameter with a constant helical pitch of 80 mm and a nominal applied force of 50 N. It may be seen that there is a local maximum for torque for pitch diameter in the range of 40 mm to 50 mm, and that there is a local minimum of efficiency in the same range. It may be inferred from FIG. 16 that pitch diameter should be set between 40 mm and 80 mm, with lower values producing greater torque at lower efficiency, and higher values providing higher efficiency but lower torque production overall. In some embodiments, a pitch diameter in the range of 50 mm to 60 mm provides a desirable compromise between torque and efficiency.
- FIG. 17 shows graphs of torque and efficiency against lead angle with a constant pitch diameter of 50 mm and a nominal applied force of 500 N. It may be seen that a local minimum for efficiency occurs with a 30 degree pitch angle (which corresponds to a helical pitch of 40 mm), increasing thereafter. It may also be seen that torque appears to increase logarithmically with respect to lead angle, with the most dramatic increases occurring over lower lead angles, and that most of the appreciable gains have been realized once the lead angle reaches 56 degrees (which corresponds to a helical pitch of 100 mm). In some embodiments, a helical pitch of 80 mm to 100 mm provides a desirable compromise between efficiency, torque, and stroke length. In some embodiments, a shorter helical pitch may be desirable because helical pitch determines the number of rotations generated per linear stroke by the user, with more rotations per linear stroke when helical pitch is shorter.
- a helical drive having a helical pitch of 90 millimeters (yielding an approximate lead angle of 25.5 degrees) and a pitch diameter of 50 millimeters in order to realize the dual goals of optimizing torque and efficiency while trying to maintain a compact drive (e.g., a drive that is appropriately sized for use in human-powered vehicles and other similarly-sized devices).
- a helical member has a helical pitch of between 70 mm and 110 mm. In some embodiments, a helical member has a helical pitch of between 75 mm and 105 mm. In some embodiments, a helical member has a helical pitch of between 80 mm and 100 mm. In some embodiments, a helical member has a helical pitch of between 85 mm and 95 mm. In some embodiments, a helical member has a helical pitch of about 90 mm. In some embodiments, a helical member has a helical pitch of 90 mm.
- a helical member has a pitch diameter of between 40 mm and 60 mm. In some embodiments, a helical member has a pitch diameter of between 42.5 mm and 57.5 mm. In some embodiments, a helical member has a pitch diameter of between 45 mm and 55 mm. In some embodiments, a helical member has a pitch diameter of between 47.5 mm and 52.5 mm. In some embodiments, a helical member has a pitch diameter of about 50 mm. In some embodiments, a helical member has a pitch diameter of 50 mm.
- a helical member has a lead angle of between 20 degrees and 30 degrees. In some embodiments, a helical member has a lead angle of between 22 degrees and 28 degrees. In some embodiments, a helical member has a lead angle of between 24 degrees and 26 degrees. In some embodiments, a helical member has a lead angle of between 25 degrees and 26 degrees. In some embodiments, a helical member has a lead angle of between 24 degrees and 27 degrees. In some embodiments, a helical member has a lead angle of about 25.5 degrees. In some embodiments, a helical member has a lead angle of 25.5 degrees.
- helical drive system 1100 use of the helical drive system 1100 will be described herein with specific reference to the helical drive system 1100 including the helical drive 100 , but it will be apparent to those of skill in the art that use of the helical drive system 1100 including the helical drive 600 will be substantially similar.
- the user moves the handle actuator 300 repeatedly back and forth along the slots 410 , 420 between a first end of the frame 400 (e.g., the end of the frame 400 that includes the drive end hole 430 ) and a second end of the frame 400 (e.g., the end of the frame 400 that includes the retention end hole 440 ).
- FIG. 18 shows the helical member 200 , the handle actuator 300 , and the follower bearings 130 , 140 with the remaining elements of the helical drive system 1100 removed.
- FIG. 19 shows the helical member 200 and the follower bearings 130 , 140 with the remaining elements of the helical drive system 1100 removed.
- FIGS. 20 and 21 show corresponding views of portions of the helical drive system 1100 that includes the helical drive 600 .
- the handle actuator 300 moves along the slots 410 , 420 in a first or “drive” direction (e.g., away from the drive end hole 430 and toward the retention end hole 440 , though it will be apparent to those of skill in the art that the “drive” direction may be in the opposite direction)
- the helical member 200 rotates about its longitudinal axis in a first or “drive” direction (e.g., clockwise, though it will be apparent to those of skill in the art that the “drive” direction may instead be counterclockwise), causing the flexible shaft 1130 and the first side 1142 of the freewheel 1140 to rotate in the “drive” direction.
- Such rotation results in torque being transmitted by the freewheel 1140 to the second side 1144 thereof, applying a torque and causing rotation of the hub 1150 in the “drive” direction.
- the handle actuator 300 moves along the slots 410 , 420 in a second or “free” direction (e.g., away from the retention end hole 440 and toward the drive end hole 430 , though it will be apparent to those of skill in the art that the “free” direction may be in the opposite direction)
- the helical member 200 rotates about its longitudinal axis in a second or “free” direction that is opposite the “drive” direction (e.g., counterclockwise, though it will be apparent to those of skill in the art that the “free” direction may instead be clockwise), causing the flexible shaft 1130 and the first side 1142 of the freewheel 1140 to rotate in the “free” direction.
- a drive mechanism including a helical drive also includes a control mechanism that is operable to selectively allow the helical drive to be driven only in one direction (e.g., to allow an actuator to generate torque when moved in a first direction while moving freely without generating torque when moved in an opposing second direction).
- a control mechanism is incorporated into a system using a negative helical form such as that shown in FIGS. 6 A- 6 D .
- FIGS. 22 - 38 show a helical drive system 2200 including an exemplary control mechanism 2300 .
- the helical drive system 2200 has a longitudinal axis 2205 .
- the helical drive system 2200 includes a helical member 3100 , a first end housing 3200 , an end bearing 3300 , a second end housing 3400 , and a bevel gear 3500 .
- the control mechanism 2300 includes a handle assembly 2400 , a housing 2500 , a bearing housing 2600 , a bearing control sleeve 2700 , a helical sleeve 2800 , bearings 2900 and 2950 , and spacers 3000 and 3050 .
- the handle assembly 2400 when assembled, defines a handle axis 2402 (see FIG. 23 ).
- the handle assembly 2400 includes an outer handle 2410 , an inner handle 2440 , and a cam mover 2470 .
- the outer handle 2410 includes a generally cylindrical handle portion 2412 defining an outer gripping surface 2414 and a bore 2416 sized and shaped to receive the inner handle 2440 .
- the outer handle 2410 incorporates other control elements (e.g., a brake control) therein.
- the inner handle 2440 includes a generally cylindrical handle portion 2442 sized and shaped to be received within the bore 2416 of the outer handle 2410 , a mounting portion 2444 , and a bore 2446 sized and shaped to receive the cam mover 2470 .
- the mounting portion 2444 includes holes 2448 that are sized and shaped to receive bolts to mount and secure the inner handle 2440 to the housing 2500 .
- a slot 2450 extends through the handle portion 2442 of the inner handle 2440 .
- the cam mover 2470 includes a generally cylindrical handle portion 2472 configured to be received within the bore 2446 of the inner handle 2440 , a generally disc-shaped cam interface portion 2474 positioned at an end of the handle portion 2472 so as to project beyond the bore 2446 of the inner handle 2440 , and a cam slot 2476 extending through the cam interface portion 2474 .
- the outer handle 2410 is attached to the cam mover 2470 by a screw that is secured to the handle portion 2412 of the outer handle 2410 , passes through the slot 2450 of the inner handle 2410 , and is secured to the handle portion 2472 of the cam mover 2470 .
- the helical drive system 2200 includes the handle assembly 2400 having fewer or more pieces, or includes a single-piece handle operable in a similar manner to the handle assembly 2400 described herein.
- the outer handle 2410 comprises a metal.
- the metal is an alloy.
- the alloy is an aluminum or steel alloy.
- the aluminum alloy is an aluminum alloy including silicon and magnesium.
- the aluminum alloy is a 6000-series aluminum alloy.
- the aluminum alloy is 6061 aluminum.
- the inner handle 2440 comprises a metal.
- the metal is one of the metals referenced above with respect to the outer handle 2410 .
- the cam mover 2470 comprises a metal.
- the metal is one of the metals referenced above with respect to the outer handle 2410 .
- the housing 2500 has a hollow generally cylindrical body 2502 centered around a longitudinal axis 2550 .
- the body 2502 that tapers to generally disc-shaped ends 2504 , 2506 .
- Circular holes 2508 , 2510 extend through respective ones of the ends 2504 , 2506 .
- the holes 2508 , 2510 are centered on the longitudinal axis 2550 .
- a generally round projection 2512 extends from a first side of the body 2502 .
- a circular hole 2514 is centered in the projection 2512 and is contiguous with the hollow center of the body 2502 .
- a slide support 2518 extends from a second side of the body 2502 opposite the projection 2512 .
- a bore 2520 extends through the slide support 2518 and is oriented parallel to the longitudinal axis 2550 .
- the bore 2520 supports a sliding bushing therein.
- the sliding bushing comprises polyoxymethylene, polytetrafluoroethylene (“PTFE”), ultra high molecular weight polyethylene (“UHMWPE”), nylon, or polycarbonate.
- the hollow body 2502 includes an internal cavity 2522 defining an inner surface 2524 .
- the housing 2500 comprises a metal.
- the metal is one of the metals referenced above with respect to the outer handle 2410 .
- the bearing housing 2600 has a generally cylindrical body 2602 with a bore 2604 extending therethrough.
- the body 2602 is sized and shaped to be positioned within the internal cavity 2522 of the housing 2500 as shown in FIG. 23 .
- Supports 2610 , 2612 , 2614 , and 2616 project from the body 2602 .
- the supports 2610 , 2612 , 2614 and 2616 are generally centered along a length of the body 2602 , and are spaced about the circumference of the body 2602 .
- the supports 2610 , 2612 , 2614 , 2616 contact the inner surface 2524 of the housing 2500 , thereby maintaining the bore 2604 of the bearing housing 2600 in alignment with the circular holes 2508 , 2510 of the housing 2500 .
- a cam pin 2620 projects from the support 2612 .
- the cam pin 2620 is sized and shaped to be received within the cam slot 2476 of the cam mover 2470 .
- the bearing housing 2600 comprises a metal.
- the metal is one of the metals referenced above with respect to the outer handle 2410 .
- the supports 2610 , 2614 , 2616 are separate elements that are joined to the bearing housing 2600 .
- the supports 2610 , 2614 , 2616 comprise polyoxymethylene, PTFE, UHMWPE, nylon, and/or polycarbonate.
- the bearing control sleeve 2700 has a generally cylindrical body 2702 having a bore 2704 extending therethrough.
- the body 2702 is sized and shaped to be received within the bore 2604 of the bearing housing 2600 as shown in FIG. 23 .
- the body 2702 has a central portion 2706 having a first outside diameter, and end portions 2708 , 2710 having a second outside diameter that is larger than the first outside diameter.
- the bearing control sleeve 2700 comprises a metal.
- the metal is one of the metals referenced above with respect to the outer handle 2410 .
- the helical sleeve 2800 comprises polyoxymethylene.
- the helical sleeve 2800 comprises PTFE, UHMWPE, nylon, polycarbonate, or another polymer possessing sufficiently high strength, low friction, and anti-galling properties to perform as will be described hereinafter.
- the helical sleeve 2800 comprises a metal having sufficiently high strength, low-friction, and anti-galling properties to perform as will be described hereinafter, such as a Babbitt metal or a bronze alloy.
- the helical sleeve 2800 has a generally cylindrical body 2802 that is sized and shaped to be received within the bore 2704 of the bearing control sleeve 2700 as shown in FIG. 23 , in a manner such that the bearing control sleeve 2700 and the helical sleeve 2800 rotate together about the longitudinal axis 2205 of the drive system 2200 .
- the helical sleeve 2800 is secured to the bearing control sleeve 2700 by one or more of a press fit, an adhesive, and/or a key (e.g., a kay comprising a carbon steel alloy, such as grade 1018 or grade 1045 carbon steel).
- the helical sleeve 2800 has a bore 2804 extending through the body 2802 and internal threads 2806 projecting inwardly into the bore 2804 .
- the bore 2804 and threads 2806 are sized and shaped to matingly receive the helical shaft 3100 as will be discussed in further detail hereinafter.
- the bearing 2900 is shown.
- the bearing 2900 is a one-way needle roller bearing having a sleeve 2910 and internal rollers 2920 .
- the bearing 2900 is configured to allow free rotation of the rollers 2920 in one direction and to prevent rotation of the rollers 2920 in an opposite second direction.
- the bearing 2900 is the one-way needle roller bearing commercialized under the trade name HF3520 by NationalSkander California Corporation of Anaheim, California.
- the bearing 2950 is a one-way needle roller bearing having a sleeve 2960 and internal rollers 2970 .
- the bearing 2960 is configured to allow free rotation of the rollers 2970 in one direction and to prevent rotation of the rollers 2970 in an opposite second direction.
- the bearing 2950 is the one-way needle roller bearing commercialized under the trade name HF3520 by NationalSkander California Corporation of Anaheim, California. In some embodiments, the bearing 2950 is identical to the bearing 2900 .
- the spacer 3000 is shown.
- the spacer 3000 is ring-shaped.
- the spacer 3000 is sized and shaped to fit around the end portion 2708 of the bearing control sleeve 2700 and to abut the inner surface 2524 of the housing 2500 , thereby supporting the positioning of the bearing control sleeve 2700 within the housing 2500 in a position and orientation such that the bore 2704 of the bearing control sleeve is aligned with the holes 2508 of the housing 2500 .
- the spacer 3050 is sized and shaped to fit around the end portion 2710 of the bearing control sleeve 2700 and to abut the inner surface 2524 of the housing 2500 , thereby supporting the positioning of the bearing control sleeve 2700 within the housing 2500 in a position and orientation such that the bore 2704 of the bearing control sleeve is aligned with the holes 2510 of the housing 2500 .
- the spacer 3050 is identical to the spacer 3000 .
- the spacers 3000 , 3050 comrpise polyoxymethylene, polytetrafluoroethylene (“PTFE”), ultra high molecular weight polyethylene (“UHMWPE”), nylon, or polycarbonate.
- the hollow body 2502 includes an internal cavity 2522 defining an inner surface 2524 .
- the helical member 3100 is shown.
- the helical member 3100 is generally similar to the helical member 700 shown in FIGS. 7 A- 7 C .
- the helical member 3100 includes an elongate body 3102 having a “negative” helix 3104 formed therein.
- the helix 3104 is sized and shaped to receive the threads 2806 of the helical sleeve 2800 .
- the helical member 3100 includes a first projection 3106 extending from first end thereof and a second projection 3108 extending from an opposite second end thereof.
- the helical member 3100 includes a gear rod 3110 extending from the second projection 3108 .
- the helical member 3100 is made of formed stainless steel.
- the helical member 3100 is made of a chromium-nickel stainless steel alloy.
- the helical member 3100 is made of type 301 stainless steel.
- the helical member 3100 is made from a cold-rolled bead-blasted stainless steel.
- the helical member 3100 is formed using a three-axis CNC helical forming machine.
- the helical member 3100 is formed using a helix forming machine such as those commercialized by Helix Flight Manufacturing Machines of Auckland, New Zealand.
- the helical member 3100 is formed using a spring forming machine.
- the first end housing 3200 has a generally flat body 3202 ; however, it will be apparent to those of skill in the art that this is only exemplary and other shapes may be appropriate depending on the nature of the device that is to be powered by the drive system 2200 .
- the body 3200 includes a first hole 3204 and a second hole 3206 .
- the first end housing 3200 comprises a metal.
- the metal is one of the metals referenced above with respect to the outer handle 2410 .
- the end bearing 3300 is shown.
- the end bearing 3300 is configured to be received and retained in the hole 3204 of the first end housing 3200 .
- the end bearing 3300 is a roller bearing that is configured to receive and retain therein the first projection 3106 of the helical member 3100 , and to allow the helical member 3100 to rotate freely about the longitudinal axis 2205 with respect to the first end housing.
- the end bearing 3300 is the bearing commercialized as model number 7902A5 by NSK Limited of Tokyo, Japan.
- the second end housing 3400 includes a solid body 3402 with a cavity 3404 formed therein.
- the second end housing 3400 includes first and second holes 3406 , 3408 extending from the cavity 3404 through a first side of the body 3402 .
- the second end housing 3400 includes a third hole 3410 extending from the cavity 3404 through an adjacent second side of the body 3402 .
- the first hole 3406 is sized and shaped to receive the second projection 3108 of the helical member 3100 and to allow the second projection 3108 to rotate within the first hole 3406 .
- the second end housing 3400 comprises a metal.
- the metal is one of the metals referenced above with respect to the outer handle 2410 .
- the bevel gear 3500 is shown.
- the bevel gear 3500 is configured to engage the gear rod 3110 of the helical member 3100 .
- the bevel gear 3500 is configured to convey output torque generated by the drive system 2200 , as will be described in detail hereinafter.
- the bevel gear 3500 engages another gear connected to a drive member that extends through the third hole 3410 of the second end housing 3400 .
- the bevel gear 3500 comprises a metal.
- the bevel gear 3500 comprises a carbon steel.
- the bevel gear 3500 comprises a grade 1144 or grade 1177 carbon steel alloy.
- the slider rod 3600 has a first end 3602 and an opposite second end 3604 .
- the first end 3602 is configured to be received by the second hole 3206 of the first end housing 3200 and retained therein in a fixed and non-moving engagement.
- the second end 3604 is configured to be received by the second hole 3408 of the second end housing 3400 and retained therein in a fixed and non-moving engagement.
- the slider rod 3600 comprises a metal.
- the metal is one of the metals referenced above with respect to the outer handle 2410 .
- the bore 2604 of the bearing housing 2600 is sized and shaped to securely receive the bearings 2900 , 2950 therein, such that the bearing housing 2600 , and the bearings 2900 , 2950 move together (e.g., along the longitudinal axis 2205 of the drive system 2200 ).
- the bearings 2900 , 2950 are secured within the bore 2604 of the bearing housing 2600 by a press fit.
- the central portion 2706 of the bearing control sleeve 2700 is sized such that the bearings 2900 , 2950 can be positioned around the central portion 2706 as shown in FIG. 23 in a manner such that the rollers 2920 , 2970 of the bearings 2900 , 2950 do not contact the central portion 2706 of the bearing control sleeve 2700 .
- the bearing control sleeve 2700 can rotate freely in either direction about the longitudinal axis 2205 with respect to the bearings 2900 , 2950 (and, thereby, with respect to the bearing housing 2600 ).
- the end portions 2708 , 2710 of the bearing control sleeve 2700 are sized such that the bearings 2900 , 2950 can be positioned around respective ones of the end portions 2708 , 2710 in a manner such that the rollers 2920 , 2970 contact the respective end portions 2708 , 2710 of the bearing control sleeve 2700 .
- the one-way operation of the bearings 2900 , 2950 allows the bearing control sleeve 2700 to rotate freely in one direction about the longitudinal axis 2205 with respect to the bearings 2900 , 2950 (and, thereby, with respect to the bearing housing 2600 ).
- the bearings 2900 , 2950 are oriented in rotationally opposite directions, such that they constrain rotational motion in opposite directions from one another.
- FIG. 37 shows the control system 2300 positioned such that the bearing housing 2600 and the bearings 2900 , 2950 have been moved longitudinally along the longitudinal axis 2205 in a direction toward the end portion 2708 of the bearing control sleeve 2700 .
- the rollers 2920 of the bearing 2900 contact the end portion 2708
- the rollers 2970 of the bearing 2950 remain aligned with, and do not contact, the central portion 2706 of the bearing control sleeve 2700 .
- the control sleeve 2700 when the bearing 2900 is positioned in this manner (i.e., with the rollers 2920 contacting the end portion 2708 ), the control sleeve 2700 is allowed to rotate freely with respect to the bearing housing 2600 in a first direction about the longitudinal axis 2205 , but is prevented from rotating with respect to the bearing housing 2600 in a second direction about the longitudinal axis 2205 .
- FIG. 38 shows the control system 2300 such that the bearing housing 2600 and the bearings 2900 , 2950 have been moved longitudinally along the longitudinal axis 2205 in a direction toward the end portion 2710 of the bearing control sleeve 2700 .
- the rollers 2970 of the bearing 2950 contact the end portion 2710
- the rollers 2920 of the bearing 2900 remain aligned with, and do not contact, the central portion 2706 of the bearing control sleeve 2700 .
- the bearing control sleeve 2700 when the bearing 2900 is positioned in this manner (i.e., with the rollers 2970 contacting the end portion 2710 ), the bearing control sleeve 2700 is allowed to rotate freely with respect to the bearing housing 2600 in the second direction about the longitudinal axis 2205 (e.g., the direction in which the bearing control sleeve 2700 is constrained from rotation when the bearing housing 2600 is positioned as shown in FIG. 37 ), but is prevented from rotating with respect to the bearing housing 2600 in the first direction about the longitudinal axis 2205 (e.g., the direction in which the bearing control sleeve 2700 is constrained from rotation when the bearing housing 2600 is positioned as shown in FIG. 37 .
- the outer handle 2410 is positioned such that a user can grip the gripping surface 2414 .
- the handle assembly 2400 engages the housing 2500 in a manner such that the user can grip the gripping surface 2414 and rotate the outer handle 2410 about the handle axis 2402 .
- Rotation of the outer handle 2410 causes corresponding rotation of the cam mover 2470 about the handle axis 2402 .
- the cam slot 2476 is repositioned, thereby acting as a cam in cooperation with the cam pin 2620 and driving movement of the bearing housing 2600 along the longitudinal axis 2205 .
- the handle assembly 2400 and the bearing housing 2600 are configured such that the handle assembly 2400 can be positioned in a “neutral” position, can be rotated about the handle axis 2402 in a first direction reach a “forward” position, and can be rotated about the handle axis 2402 in an opposing second direction to reach a “reverse” position.
- the “neutral” position as shown in FIG.
- the bearing housing 2600 is positioned such that the bearings 2900 , 2950 are both aligned with the central portion 2706 of the bearing control sleeve 2700 , as a result of which the bearing control sleeve 2700 can rotate freely in either direction about the longitudinal axis 2205 with respect to the bearing housing 2600 .
- the “forward” position as shown in FIG.
- the bearing housing 2600 is positioned such that the bearing 2900 is aligned with the end portion 2708 of the bearing control sleeve 2700 and the bearing 2950 is aligned with the central portion 2706 of the bearing control sleeve 2700 , as a result of which the bearing control sleeve 2700 can rotate freely in a first direction about the longitudinal axis 2205 with respect to the bearing housing 2600 , but is prevented from rotating in an opposing second direction about the longitudinal axis 2205 with respect to the bearing housing 2600 .
- the “reverse” position as shown in FIG.
- the bearing housing 2600 is positioned such that the bearing 2950 is aligned with the end portion 2710 of the bearing control sleeve 2700 and the bearing 2900 is aligned with the central portion 2706 of the bearing control sleeve 2700 , as a result of which the bearing control sleeve 2700 can rotate freely in the second direction about the longitudinal axis 2205 with respect to the bearing housing 2600 , but is prevented from rotating in the first direction about the longitudinal axis 2205 with respect to the bearing housing 2600 .
- rotation of the handle assembly 2400 about the handle axis controls the direction in which the bearing control sleeve 2700 is allowed to rotate.
- the end bearing 3300 is received in the first hole 3204 of the first end housing 3200 .
- the first end 3106 of the helical member 3100 is received by the end bearing 3300 .
- the first end 3602 of the slider rod 3600 is received and retained in the second hole 3204 of the first end housing 3200 .
- the control system 2300 assembled as shown in FIG.
- the second end housing 3400 is engaged to the drive system 2200 by passing the second projection 3108 of the helical member 3100 through the first hole 3406 of the second end housing 3400 , and by fixing the second end 3604 of the slider rod 3600 in the second hole 3408 of the second end housing 3400 .
- the helical member 3100 is secured to the second end housing 3400 by engaging the bevel gear 3500 to the gear rod 3110 of the helical member 3100 .
- the control system 2300 can slide freely along the slider rod 3600 . In some embodiments, motion of the control system 2300 with respect to the helical member 3100 operates as described hereinafter.
- the bearing control sleeve 2700 and the helical sleeve 2800 are not constrained from rotation about the longitudinal axis 2205 , such force against the helix 3104 causes the bearing control sleeve 2700 and the helical sleeve 2800 to rotate about the longitudinal axis 2205 with respect both to the helical member 3100 and to the bearing housing 2600 , enabling the internal threads 2806 of the helical sleeve 2800 to rotate within the helix 3104 of the helical member 3100 .
- the helical member 3100 is not rotated about the longitudinal axis 2205 , and no torque is generated at the bevel gear 3500 in either direction.
- the bearing control sleeve 2700 , and the helical sleeve 2800 received fixedly therein are allowed to rotate freely about the longitudinal axis 2205 in a first direction with respect to the bearing housing 2600 , but are constrained from rotating about the longitudinal axis 2205 in an opposite second direction with respect to the bearing housing due to the engagement of the bearing 2900 with the end 2708 of the bearing control sleeve 2700 .
- the bearing control sleeve 2700 and the helical sleeve 2800 rotate in the first direction about the longitudinal axis 2205 as described above with reference to the “neutral” position, the helical member 3100 is not rotated about the longitudinal axis 2205 , and no torque is generated at the bevel gear 3500 .
- the applied force causes the helical member 3100 to rotate about the longitudinal axis 2205 in order for the helix 3104 to remain in engagement with the internal threads 2806 of the helical sleeve 2800 as the helical sleeve 2800 (along with the remainder of the control system 2300 ) moves along the longitudinal axis, thereby generating a torque at the bevel gear 3500 .
- the handle assembly 2400 when the handle assembly 2400 is in the “forward” position, linear motion of the control system 2300 in the first direction does not generate a torque at the bevel gear 3500 , but linear motion of the control system 2300 in the second direction generates a “forward” torque at the bevel gear 3500 .
- the applied force causes the helical member 3100 to rotate about the longitudinal axis 2205 in order for the helix 3104 to remain in engagement with the internal threads 2806 of the helical sleeve 2800 as the helical sleeve 2800 (along with the remainder of the control system 2300 ) moves along the longitudinal axis, thereby generating a torque at the bevel gear 3500 that is opposite to the torque generated as discussed above with reference to FIG. 37 .
- the handle assembly 2400 can be rotated by a user to place the control system 2300 in either a “neutral” position, a “forward” position, or a “reverse” position.
- the control system 2300 is in the “neutral” position, the user can apply force to the handle assembly to move the control system 2300 along the helical member 3100 in either direction, and motion in either direction results in free movement of the control system 2300 without generation of any output torque at the bevel gear 3500 .
- the control system 2300 When the control system 2300 is in the “forward” position, the user can apply force to the handle to move the control system 2300 along the helical member 3100 in a first direction, and such motion generates an output torque in a first (e.g., forward) torque direction at the bevel gear 3500 . However, while the control system 2300 is in the “forward” position, the user can apply force to the handle to move the control system 2300 along the helical member 3100 in a second direction that is opposite the first direction, and such motion generates no output torque at the bevel gear 3500 .
- a first e.g., forward
- the control system 2300 When the control system 2300 is in the “reverse” position, the user can apply force to the handle to move the control system 2300 along the helical member 3100 in the second direction, and such motion generates an output torque in a second (e.g., reverse) torque direction that is opposite the first torque direction at the bevel gear 3500 .
- a second (e.g., reverse) torque direction that is opposite the first torque direction at the bevel gear 3500 .
- the drive system 2200 is suitable for use in human-powered devices, such as a wheelchair, in which a user may wish to be able to apply a linear force to thereby generate output torque in two opposed directions.
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Abstract
A device including a frame; an actuator attached to the frame and slidaby movable with respect to the frame along a linear axis, and a helical member positioned within the frame and rotatably movable with respect to the frame about a helical axis of the helical member, wherein the helical axis is parallel to the linear axis, wherein the actuator and the helical member are configured to cooperate with one another such that (a) motion of the actuator along the linear axis in a first linear direction causes corresponding rotation of the helical member about the helical axis in a first rotational direction and (b) motion of the actuator along the linear axis in a second linear direction that is opposite the first linear direction causes corresponding rotation of the helical member about the helical axis in a second rotational direction that is opposite the first rotational direction.
Description
- This application is a continuation of commonly-owned, co-pending U.S. patent application Ser. No. 16/925,681, filed Jul. 10, 2020, entitled “HELICAL DRIVE MECHANISM AND HANDLE MECHANISM FOR WHEELCHAIR WITH HELICAL DRIVE,” which claims benefit of commonly-owned, co-pending U.S. Provisional Patent Application No. 62/873,734, filed Jul. 12, 2020, entitled HELICAL DRIVE MECHANISM, and U.S. Provisional Patent Application No. 62/965,051, filed Jan. 23, 2020, entitled HANDLE MECHANISM FOR WHEELCHAIR WITH HELICAL DRIVE, the contents of both of which are incorporated herein by reference in their entirety.
- The field of invention relates to human-powered drive mechanisms. More particularly, the field of invention relates to control mechanisms for human-powered drive mechanisms that are operable to convert a linear input force to a helical drive torque through the use of a helical element.
- Vehicles and other human-powered devices that are driven by a rotational drive torque are known. However, such devices are inefficient and require the application of human input power in a manner that may not be biomechanically desirable.
- Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced.
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FIG. 1A shows a perspective view of a first exemplary embodiment of a helical drive; -
FIG. 1B shows a side view of the helical drive ofFIG. 1A ; -
FIG. 1C shows a top view of the helical drive ofFIG. 1A ; -
FIG. 1D shows a front view of the helical drive ofFIG. 1A ; -
FIG. 2A shows a perspective view of a helical member of the helical drive ofFIG. 1A ; -
FIG. 2B shows a side view of the helical member ofFIG. 2A ; -
FIG. 2C shows a front view of the helical member ofFIG. 2A ; -
FIG. 3A shows a perspective view of an actuator handle of the helical drive ofFIG. 1A ; -
FIG. 3B shows a side view of the actuator handle ofFIG. 3A ; -
FIG. 3C shows a top view of the actuator handle ofFIG. 3A ; -
FIG. 4A shows a perspective view of a frame of the helical drive ofFIG. 1A ; -
FIG. 4B shows a side view of the frame ofFIG. 4A ; -
FIG. 4C shows a top view of the frame ofFIG. 4A ; -
FIG. 4D shows a front view of the frame ofFIG. 4A ; -
FIG. 5A shows a perspective view of a subassembly including the actuator handle ofFIG. 3A and the frame ofFIG. 4A ; -
FIG. 5B shows a side view of the subassembly ofFIG. 5A ; -
FIG. 5C shows a top view of the subassembly ofFIG. 5A ; -
FIG. 5D shows a front view of the subassembly ofFIG. 5A ; -
FIG. 6A shows a perspective view of a second exemplary embodiment of a helical drive; -
FIG. 6B shows a side view of the helical drive ofFIG. 6A ; -
FIG. 6C shows a top view of the helical drive ofFIG. 6A ; -
FIG. 6D shows a front view of the helical drive ofFIG. 6A ; -
FIG. 7A shows a perspective view of a helical member of the helical drive ofFIG. 6A ; -
FIG. 7B shows a side view of the helical member ofFIG. 7A ; -
FIG. 7C shows a front view of the helical member ofFIG. 7A ; -
FIG. 8A shows a perspective view of an actuator handle of the helical drive ofFIG. 6A ; -
FIG. 8B shows a side view of the actuator handle ofFIG. 8A ; -
FIG. 8C shows a front view of the actuator handle ofFIG. 8A ; -
FIG. 8D shows a top view of the actuator handle ofFIG. 8A ; -
FIG. 9A shows a perspective view of a frame of the helical drive ofFIG. 6A ; -
FIG. 9B shows a side view of the frame ofFIG. 9A ; -
FIG. 9C shows a top view of the frame ofFIG. 9A ; -
FIG. 9D shows a front view of the frame ofFIG. 9A ; -
FIG. 10A shows a perspective view of a subassembly including the actuator handle ofFIG. 8A and the frame ofFIG. 9A ; -
FIG. 10B shows a side view of the subassembly ofFIG. 10A ; -
FIG. 10C shows a top view of the subassembly ofFIG. 10A ; -
FIG. 10D shows a front view of the subassembly ofFIG. 10A ; -
FIG. 11 shows a perspective view of a helical drive system including the helical drive ofFIG. 1A ; -
FIG. 12 shows a side view of a representative helical section; -
FIG. 13 shows a cross-sectional view of a representative helical section; -
FIG. 14 shows a graph of torque and frictional force against applied force for a helical drive; -
FIG. 15 shows a graph of efficiency against applied force for a helical drive; -
FIG. 16 shows graphs of torque and efficiency against pitch diameter for a helical drive; -
FIG. 17 shows graphs of torque and efficiency against lead angle for a helical drive; -
FIG. 18 shows a first subset of selected elements of a helical drive system including the helical drive ofFIG. 1A ; -
FIG. 19 shows a second subset of selected elements of a helical drive system including the helical drive ofFIG. 1A ; -
FIG. 20 shows a first subset of selected elements of a helical drive system including the helical drive ofFIG. 6A ; -
FIG. 21 shows a second subset of selected elements of a helical drive system including the helical drive ofFIG. 6A . -
FIG. 22 shows a perspective view of a third exemplary embodiment of a helical drive; -
FIG. 23 shows a section view of a control system of the helical drive ofFIG. 22 ; -
FIG. 24 shows an exploded view of a handle assembly of the helical drive ofFIG. 22 ; -
FIG. 25A shows a perspective view of a housing of the helical drive ofFIG. 22 ; -
FIG. 25B shows a section view of the housing ofFIG. 25A ; -
FIG. 26 shows a perspective view of a bearing housing of the helical drive ofFIG. 22 ; -
FIG. 27 shows a perspective view of a bearing control sleeve of the helical drive ofFIG. 22 ; -
FIG. 28 shows a perspective view of a helical sleeve of the helical drive ofFIG. 22 ; -
FIG. 29 shows a perspective view of a one-way bearing of the helical drive ofFIG. 22 ; -
FIG. 30 shows a perspective view of a spacer of the helical drive ofFIG. 22 ; -
FIG. 31 shows a perspective view of a helical member of the helical drive ofFIG. 22 ; -
FIG. 32 shows a perspective view of a first end housing of the helical drive ofFIG. 22 ; -
FIG. 33 shows a perspective view of an end bearing of the helical drive ofFIG. 22 ; -
FIG. 34 shows a perspective view of a second end housing of the helical drive ofFIG. 22 ; -
FIG. 35 shows a perspective view of a bevel gear of the helical drive ofFIG. 22 ; -
FIG. 36 shows a perspective view of a slider rod of the helical drive ofFIG. 22 ; -
FIG. 37 shows a section view of the control system ofFIG. 23 , a handle assembly having been actuated to position the control system in a “forward” configuration; and -
FIG. 38 shows a section view of the control system ofFIG. 23 , a handle assembly having been actuated to position the control system in a “reverse” configuration. - The exemplary embodiments relate to a helical drive suitable for use in human-powered vehicles and similar devices, and operable to receive linear force and motion as an input and provide torque as an output.
- In an embodiment, a helical drive includes a frame, a handle actuator attached to the frame and slidaby movable along the frame along a linear axis, and a helical member positioned within the frame and rotatably movable within the frame about a longitudinal axis parallel to the linear axis, whereby motion of the handle actuator along the linear axis causes corresponding rotation of the helical member about the longitudinal axis. In some embodiments, the helical drive includes at least one follower bearing positioned on a portion of the handle actuator so as to reduce friction between the handle actuator and the helical member. In some embodiments, the helical drive includes at least one plain bearing positioned on a portion of the frame so as to reduce friction between the helical member and the frame. In some embodiments, the helical member has a helical pitch of between 85 millimeters and 95 millimeters. In some embodiments, the helical member has a lead angle of between 24 degrees and 27 degrees. In some embodiments, the helical member has a pitch diameter of between 48 millimeters and 52 millimeters.
- In an embodiment, a helical drive system includes a helical drive, a flexible drive shaft, and a freewheel, wherein the helical drive includes a frame, a handle actuator attached to the frame and slidaby movable along the frame along a linear axis, and a helical member positioned within the frame and rotatably movable within the frame about a longitudinal axis parallel to the linear axis, whereby motion of the handle actuator along the linear axis causes corresponding rotation of the helical member about the longitudinal axis, wherein the flexible drive shaft is coupled to the helical member such that rotation of the helical member causes corresponding rotation of the flexible drive shaft, and wherein the flexible drive shaft is coupled to the freewheel. In some embodiments, the helical drive includes at least one follower bearing positioned on a portion of the handle actuator so as to reduce friction between the handle actuator and the helical member. In some embodiments, the helical drive includes at least one plain bearing positioned on a portion of the frame so as to reduce friction between the helical member and the frame. In some embodiments, the helical member has a helical pitch of between 85 millimeters and 95 millimeters. In some embodiments, the helical member has a lead angle of between 24 degrees and 27 degrees. In some embodiments, the helical member has a pitch diameter of between 48 millimeters and 52 millimeters.
- In some embodiments, a helical drive system includes a control system, the control system including a handle assembly that is operable to selectively position the control system in a “neutral” position, a “forward” position, or a “reverse” position. In some embodiments, the helical drive system includes a helical member having at least one helical depression formed therein. In some embodiments, the control system includes a sleeve surrounding the helical member, the sleeve having at least one internal thread engaging the at least one helical depression of the helical member. In some embodiments, the control system includes at least a first one-way bearing and a second one-way configured to selectively engage the sleeve, wherein, when the first one-way bearing is engaged to the sleeve, the first one-way bearing allows the sleeve to rotate with respect to the helical member in a first direction and prevents the sleeve from rotating with respect to the helical member in a second direction that is opposite the first direction, and wherein, when the second one-way bearing is engaged to the sleeve, the second one-way bearing allows the sleeve to rotate with respect to the helical member in the second direction and prevents the sleeve from rotating with respect to the helical member in the first direction.
- [[TO BE COMPLETED ONCE CLAIMS ARE FINALIZED]]
- In some embodiments, a helical drive includes a helical member having a longitudinal axis, a frame containing the helical member, and a handle actuator movable along the frame in a direction parallel to the longitudinal axis of the helical member, thereby to induce the helical to rotate about its longitudinal axis.
- In some embodiments, a helical drive includes a “positive” or “open” helical form to allow a rigid member to actuate the helical as the user applies a linear force along the primary axis of the drive, and a simple frame is used to provide a guide for the handle actuator, provide stability for the cylindrical elements of the drive, and housing surfaces for the plain bearings. In some embodiments, a helical drive includes a handle actuator, at least one follower bearing, a frame, an end cap, at least one plane bearing, an output shaft, and a helical member.
- In some embodiments, a helical drive includes a “negative” or “solid” helical form including a helical path cut into a helical drive member. In some embodiments, a helical drive includes a surrounding cuff to support follower bearings. In some embodiments, when the handle is moved along the provided slot, the follower bearings make contact with the helical path cut into the drive member. In some embodiments, as the user actuates the handle, the force is applied to the helical path through the followers, thereby rotating the helical member and, in turn, the output shaft. In some embodiments, a simple frame is used to provide a guide for the handle, to provide stability for the cylindrical elements of the drive, and to provide housing surfaces for the plain bearings, while a secondary cuff provides support for the follower bearings.
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FIGS. 1A-1D show an exemplaryhelical drive 100 that includes a “positive” or “open” helical form from various view angles.FIG. 1A shows a perspective view,FIG. 1B shows a side view,FIG. 1C shows a top view, andFIG. 1D shows a front view. -
FIGS. 2A-2C shows an exemplaryhelical member 200 of thehelical drive 100 ofFIGS. 1A-1D .FIG. 2A shows a perspective view,FIG. 2B shows a side view, andFIG. 2C shows a front view. Thehelical member 200 includes ahelical channel 202 extending along and around substantially the entire length thereof. The exemplaryhelical member 200 is provided with adrive end cap 210 and aretention end cap 220, which are fixed to opposing ends of thehelical member 200 such that an essentially inseparable whole is formed. In some embodiments, thedrive end cap 210 and theretention end cap 220 are fixed to thehelical member 200 by rivets. In some embodiments, thedrive end cap 210 is configured to provide output torque, such as to a drive shaft. In some embodiments, thehelical member 200 is made of formed stainless steel. In some embodiments, thehelical member 200 is made of a chromium-nickel stainless steel alloy. In some embodiments, thehelical member 200 is made of type 301 stainless steel. In some embodiments, thehelical member 200 is made from a cold-rolled bead-blasted stainless steel. In some embodiments, thehelical member 200 is formed using a three-axis CNC helical forming machine. In some embodiments, thehelical member 200 is formed using a helix forming machine such as those commercialized by Helix Flight Manufacturing Machines of Auckland, New Zealand. In some embodiments, thehelical member 200 is formed using a spring forming machine. -
FIGS. 3A-3C show anexemplary handle actuator 300 of thehelical drive 100 ofFIGS. 1A-1D .FIG. 3A shows a perspective view,FIG. 3B shows a side view, andFIG. 3C shows a top view. Thehandle actuator 300 includesrecesses handle actuator 300 is made from an aluminum alloy. In some embodiments, thehandle actuator 300 is made by a stamping process. In some embodiments, thehandle actuator 300 is made from an alloy including aluminum, magnesium, and silicon, such as 6061 aluminum. -
FIGS. 4A-4D show anexemplary frame 400 of thehelical drive 100 ofFIGS. 1A-1D .FIG. 4A shows a perspective view,FIG. 4B shows a side view,FIG. 4C shows a top view, andFIG. 4D shows a front view. Theframe 400 includes atop slot 410 and a bottom slot 420 (collectively “theslots handle actuator 300 therein in a manner such that thehandle actuator 300 is free to move along theframe 400 along an allowable travel defined by the length of thetop slot 410 and thebottom slot 420. Theframe 400 includes adrive end hole 430 and aretention end hole 440, which are configured to receive thedrive end cap 210 and theretention end cap 220, respectively, of thehelical member 200, thereby to retain thehelical member 200 within theframe 400 and to allow thehelical member 200 to rotate along its longitudinal axis with respect to theframe 400.FIGS. 5A-5D show an exemplary partially assembled view of theframe 400 and thehandle actuator 300.FIG. 5A shows a perspective view,FIG. 5B shows a side view,FIG. 5C shows a top view, andFIG. 5D shows a front view. In some embodiments, theframe 400 is made from an aluminum alloy. In some embodiments, theframe 400 is made by a stamping process. In some embodiments, theframe 400 is made from an alloy including aluminum, magnesium, and silicon, such as 6061 aluminum. - Referring back to
FIGS. 1A-1D , thehelical drive 100 includesplain bearings drive end hole 430 and theretention end hole 440, respectively, of theframe 400, and about thedrive end cap 210 and theretention end cap 220, respectively, of thehelical member 200, thereby to reduce rotational friction when thehelical member 200 rotates about its longitudinal axis. Thehelical drive 100 also includesfollower bearings recesses handle actuator 300, thereby to reduce friction when thehandle actuator 300 moves along theslots frame 400 to drive rotational motion of thehelical member 200. In some embodiments, at least one of theplain bearings plain bearings follower bearings -
FIGS. 6A-6D show various views of an exemplaryhelical drive 600 that includes a “negative” or “solid” helical form.FIG. 6A shows a perspective view,FIG. 6B shows a side view,FIG. 6C shows a top view, andFIG. 6D shows a front view. -
FIGS. 7A-7C shows an exemplaryhelical member 700 of thehelical drive 600 ofFIGS. 6A-6D .FIG. 7A shows a perspective view,FIG. 7B shows a side view, andFIG. 7C shows a front view. Thehelical member 700 includes ahelical channel 702 extending along and around substantially the entire length thereof. The exemplaryhelical member 700 is provided with adrive end cap 710 and aretention end cap 720, which are fixed to opposing ends of thehelical member 700 such that an essentially inseparable whole is formed. In some embodiments, thedrive end cap 710 and theretention end cap 720 are fixed to thehelical member 700 by rivets. In some embodiments, thedrive end cap 710 is configured to provide output torque, such as to a drive shaft. In some embodiments, thehelical member 700 is made of formed stainless steel. In some embodiments, thehelical member 700 is made of a chromium-nickel stainless steel alloy. In some embodiments, thehelical member 700 is made of type 301 stainless steel. In some embodiments, thehelical member 700 is made from a cold-rolled bead-blasted stainless steel. In some embodiments, thehelical member 700 is formed using a three-axis CNC helical forming machine. In some embodiments, thehelical member 700 is formed using a helix forming machine such as those commercialized by Helix Flight Manufacturing Machines of Auckland, New Zealand. In some embodiments, thehelical member 700 is formed using a spring forming machine. -
FIGS. 8A-8C show anexemplary handle actuator 800 of thehelical drive 600 ofFIGS. 6A-6D .FIG. 8A shows a perspective view,FIG. 8B shows a side view,FIG. 8C shows a front view, andFIG. 8D shows a top view. Thehandle actuator 800 includes ahandle portion 810, aframe portion 820, and prongs 830 and 840 extending from theframe portion 820 that are sized and shaped to receive follower bearings, which will be described in further detail hereinafter. In some embodiments, thehandle actuator 800 is made from an aluminum alloy. In some embodiments, thehandle actuator 800 is made by a stamping process. In some embodiments, thehandle actuator 800 is made from an alloy including aluminum, magnesium, and silicon, such as 6061 aluminum. -
FIGS. 9A-9D show anexemplary frame 900 of thehelical drive 600 ofFIGS. 6A-6D .FIG. 9A shows a perspective view,FIG. 9B shows a side view,FIG. 9C shows a top view, andFIG. 9D shows a front view. Theframe 400 is sized and shaped to be received within theframe portion 820 of the handle actuator 800 (see, e.g.,FIG. 10A ) such that thehandle actuator 800 can move along theframe 800. Theframe 800 includes atop slot 810 and a bottom slot 820 (collectively “theslots prongs handle actuator 800 therein in a manner such that thehandle actuator 800 is free to move along theframe 900 along an allowable travel defined by the length of thetop slot 910 and thebottom slot 920. Theframe 900 includes adrive end hole 930 and aretention end hole 940, which are configured to receive thedrive end cap 710 and theretention end cap 720, respectively, of thehelical member 700, thereby to retain thehelical member 700 within theframe 900 and to allow thehelical member 700 to rotate along its longitudinal axis with respect to theframe 900. Figures show an exemplary partially assembled view of theframe 900 and thehandle actuator 800.FIG. 10A shows a perspective view,FIG. 10B shows a side view,FIG. 10C shows a top view, andFIG. 10D shows a front view. In some embodiments, theframe 900 is made from an aluminum alloy. In some embodiments, theframe 900 is made by a stamping process. In some embodiments, theframe 900 is made from an alloy including aluminum, magnesium, and silicon, such as 6061 aluminum. - Referring back to
FIGS. 6A-6D , thehelical drive 600 includesplain bearings drive end hole 930 and theretention end hole 940, respectively, of theframe 900, and about thedrive end cap 710 and theretention end cap 720, respectively, of thehelical member 700, thereby to reduce rotational friction when thehelical member 700 rotates about its longitudinal axis. Thehelical drive 600 also includesfollower bearings 630 and 640 (seeFIG. 21 ) that are positioned over theprongs handle actuator 800, thereby to reduce friction when thehandle actuator 800 moves along theslots frame 900 to drive rotational motion of thehelical member 700. In some embodiments, at least one of theplain bearings plain bearings follower bearings -
FIG. 11 shows a perspective view of ahelical drive system 1100. In some embodiments, such as the embodiment shown inFIG. 11 , thehelical drive system 1100 includes thehelical drive 100 described above with reference toFIGS. 1A-5D . However, it will be apparent to those of skill in the art that in other embodiments, thehelical drive system 1100 may include a different helical drive such as thehelical drive 600 described above with reference toFIGS. 6A-10D . In thehelical drive system 1100, thehelical drive 100 is secured to a structural element 1110 (e.g., a structural member of a vehicle that is to be driven by the helical drive 100). In some embodiments, thehelical drive 100 is secured to thestructural element 1110 by aclamp 1120. However, it will be apparent to those of skill in the art that thehelical drive 100 may be secured to thestructural element 1110 by any other suitable fastening mechanism known in the art. It will also be apparent to those of skill in the art that thehelical drive 100 need not be secured to thestructural element 1110 by theclamp 1120 or other fastening mechanism located at the specific location of theframe 400 shown inFIG. 11 , and may be secured to thestructural element 1110 at any other position along theframe 400 of thehelical drive 100. - Continuing to refer to
FIG. 11 , thehelical drive system 1100 also includes aflexible output shaft 1130 having a first end 1132 and a second end 1134 opposite the first end 1132. In some embodiments, theflexible shaft 1130 is a flexible shaft that is capable of transmitting rotary motions/torques while bent around a desired path. In some embodiments, theflexible shaft 1130 is capable of rotation at speeds of up to 10,000 rpm. In some embodiments, theflexible shaft 1130 has a circular cross-section. In some embodiments, theflexible shaft 1130 has a diameter of 0.25 inches. In some embodiments, theflexible shaft 1130 is capable of transmitting an applied torque of up to 110 inch-pounds. In some embodiments, theflexible shaft 1130 is made from a steel alloy. In some embodiments, theflexible shaft 1130 is capable of performing as described above while flexed to a bend radius of 5 inches or more. In some embodiments, theflexible shaft 1130 is similar to the flexible shafts commercialized the McMaster-Carr Supply Company of Elmhurst, Illinois as part number 3787. In some embodiments, the first end 1132 of theflexible shaft 1130 is secured to thedrive end cap 210 of thehelical member 200 of thehelical drive 100 by a set screw connection, thereby to transmit torque from thehelical member 200 to the first end 1132 of theflexible shaft 1130 and along theflexible shaft 1130 to the second end 1134 thereof. - Continuing to refer to
FIG. 11 , thehelical drive system 1100 includes afreewheel 1140. As will be known to those of skill in the art, a freewheel is a transmission device that disengages a driveshaft (e.g., the flexible shaft 1130) from a driven shaft (e.g., a downstream component of a drive train that is driven by the driveshaft) when the driven shaft rotates faster than the driveshaft. In some embodiments, such disengagement occurs, for example, when the driven shaft is rotating in a first direction (e.g., a direction that propels a vehicle in a primary travel direction) and the driveshaft is rotated in a second direction opposite the first direction. In some embodiments, thefreewheel 1140 is similar to the freewheel commercialized by Shimano, Inc. of Sakai, Japan under the trade name RM33. Thefreewheel 1140 includes afirst side 1142 that is coupled to theflexible shaft 1130 and asecond side 1144 opposite thefirst side 1142. - Continuing to refer to
FIG. 11 , thehelical drive system 1100 includes ahub 1150. In some embodiments, thehub 1150 is the hub of a wheel to be driven by thehelical drive system 1100, thereby to drive a vehicle. In some embodiments, thehub 1150 drives a vehicle or other device to be driven by the helical drive system in a manner commensurate with the operation of the vehicle or other device. Thehub 1150 is coupled to thesecond side 1144 of thefreewheel 1140. - In some embodiments, the torque generated by the
helical drive FIG. 12 shows a side view of a representative helical section, wherein r represents the radius, Dp represents the pitch diameter, and L represents the lead.FIG. 13 shows a cross-section of a helical section to illustrate torque, wherein Fo represents the orthogonal force and r represents the radius. - In some embodiments, the orthogonal component of the force can be understood by “unravelling” one pitch (e.g., rotation) of the helical path into an incline plane relationship. In some embodiments, the follower bearing can be understood to be working against the plane to develop the orthogonal force Fo. In some embodiments, a number of other forces arrive, including the frictional force FF. In some embodiments, the forces also include the normal force FN, the vertical component of which will act as “thrust” along the axis of the bearing and may be considered when selecting the bearings.
FIG. 1400 relationship of these forces based on the selected helical angle λ. The following equations may then be considered in designing thehelical drive 100 or 600: -
- In the above, Equation (1) is the standard definition of torque, and is used to translate the orthogonal force into torque delivered at the shaft output. Equation (3) translates the applied downward force Fa into the component Fo and further into the applied torque about the central axis of the drive via Equation (1), where r is half of the pitch diameter. Efficiency of the drive output, which can be understood to equal the ratio of actual torque output with frictional losses to ideal torque output without frictional losses, is calculated via Equation (4) above.
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FIG. 14 shows graphs of torque and frictional force against applied force for a helical drive including a 50 mm pitch diameter and a helical pitch of 80 mm (which correspond to a lead angle of 27 degrees). It may be seen that there is a linear relationship between torque and applied force, and that increased force results in increased torque with no particular local maxima. It may also be seen that there is a linear relationship between frictional force and applied force. -
FIG. 15 shows a graph of efficiency against applied force for a helical drive having dimensions as noted above. It may be seen that there is a precipitous drop in efficiency between 0 and 200 N and a gradual decline thereafter. In some embodiments, this may suggest that greater efficiency is achieved with applied forces below the average possible from a given user. -
FIG. 16 shows graphs of torque and efficiency for varying values of pitch diameter with a constant helical pitch of 80 mm and a nominal applied force of 50 N. It may be seen that there is a local maximum for torque for pitch diameter in the range of 40 mm to 50 mm, and that there is a local minimum of efficiency in the same range. It may be inferred fromFIG. 16 that pitch diameter should be set between 40 mm and 80 mm, with lower values producing greater torque at lower efficiency, and higher values providing higher efficiency but lower torque production overall. In some embodiments, a pitch diameter in the range of 50 mm to 60 mm provides a desirable compromise between torque and efficiency. -
FIG. 17 shows graphs of torque and efficiency against lead angle with a constant pitch diameter of 50 mm and a nominal applied force of 500 N. It may be seen that a local minimum for efficiency occurs with a 30 degree pitch angle (which corresponds to a helical pitch of 40 mm), increasing thereafter. It may also be seen that torque appears to increase logarithmically with respect to lead angle, with the most dramatic increases occurring over lower lead angles, and that most of the appreciable gains have been realized once the lead angle reaches 56 degrees (which corresponds to a helical pitch of 100 mm). In some embodiments, a helical pitch of 80 mm to 100 mm provides a desirable compromise between efficiency, torque, and stroke length. In some embodiments, a shorter helical pitch may be desirable because helical pitch determines the number of rotations generated per linear stroke by the user, with more rotations per linear stroke when helical pitch is shorter. - Based on the graphs discussed above, certain conclusions may be drawn. It may be concluded that the relationship between torque output, frictional losses and force input are linear regardless of other dimensions or parameters. It may further be concluded that, in some embodiments, there is an advantage to increasing lead angle in order to improve torque output at the sacrifice of efficiency, although efficiency varies slightly when compared with the relative gains in torque output. It may be further be concluded that the peak in torque output when evaluating different pitch diameters is tied directly to the selected, and larger lead angles reward (i.e., provide improved torque output in connection with larger pitch diameters). Accordingly, it may be concluded that, in some embodiments, it is advantageous to have both a large pitch diameter and a large lead angle. It may further be concluded that advantageous performance may be realized with a helical drive having a helical pitch of 90 millimeters (yielding an approximate lead angle of 25.5 degrees) and a pitch diameter of 50 millimeters in order to realize the dual goals of optimizing torque and efficiency while trying to maintain a compact drive (e.g., a drive that is appropriately sized for use in human-powered vehicles and other similarly-sized devices).
- In some embodiments, a helical member has a helical pitch of between 70 mm and 110 mm. In some embodiments, a helical member has a helical pitch of between 75 mm and 105 mm. In some embodiments, a helical member has a helical pitch of between 80 mm and 100 mm. In some embodiments, a helical member has a helical pitch of between 85 mm and 95 mm. In some embodiments, a helical member has a helical pitch of about 90 mm. In some embodiments, a helical member has a helical pitch of 90 mm.
- In some embodiments, a helical member has a pitch diameter of between 40 mm and 60 mm. In some embodiments, a helical member has a pitch diameter of between 42.5 mm and 57.5 mm. In some embodiments, a helical member has a pitch diameter of between 45 mm and 55 mm. In some embodiments, a helical member has a pitch diameter of between 47.5 mm and 52.5 mm. In some embodiments, a helical member has a pitch diameter of about 50 mm. In some embodiments, a helical member has a pitch diameter of 50 mm.
- In some embodiments, a helical member has a lead angle of between 20 degrees and 30 degrees. In some embodiments, a helical member has a lead angle of between 22 degrees and 28 degrees. In some embodiments, a helical member has a lead angle of between 24 degrees and 26 degrees. In some embodiments, a helical member has a lead angle of between 25 degrees and 26 degrees. In some embodiments, a helical member has a lead angle of between 24 degrees and 27 degrees. In some embodiments, a helical member has a lead angle of about 25.5 degrees. In some embodiments, a helical member has a lead angle of 25.5 degrees.
- Referring back to
FIG. 11 , use of thehelical drive system 1100 will be described herein with specific reference to thehelical drive system 1100 including thehelical drive 100, but it will be apparent to those of skill in the art that use of thehelical drive system 1100 including thehelical drive 600 will be substantially similar. When thehelical drive system 1100 is in use, the user moves thehandle actuator 300 repeatedly back and forth along theslots frame 400 that includes the drive end hole 430) and a second end of the frame 400 (e.g., the end of theframe 400 that includes the retention end hole 440). Reciprocal motion of thehandle actuator 300 in this manner forcesfollower bearings helical channel 202 of thehelical member 200, thereby inducing rotation of thehelical member 200 along its longitudinal axis corresponding to the motion of thehandle actuator 300 along theslots FIG. 18 shows thehelical member 200, thehandle actuator 300, and thefollower bearings helical drive system 1100 removed.FIG. 19 shows thehelical member 200 and thefollower bearings helical drive system 1100 removed.FIGS. 20 and 21 show corresponding views of portions of thehelical drive system 1100 that includes thehelical drive 600. These figures are illustrative to show the manner in which linear motion of thehandle actuator 300 to force thefollower bearings helical member 200. Rotation of thehelical member 200 along its longitudinal axis causes corresponding rotation of theflexible shaft 1130 and application of torque to thefirst side 1142 of thefreewheel 1140. - When the
handle actuator 300 moves along theslots drive end hole 430 and toward theretention end hole 440, though it will be apparent to those of skill in the art that the “drive” direction may be in the opposite direction), thehelical member 200 rotates about its longitudinal axis in a first or “drive” direction (e.g., clockwise, though it will be apparent to those of skill in the art that the “drive” direction may instead be counterclockwise), causing theflexible shaft 1130 and thefirst side 1142 of thefreewheel 1140 to rotate in the “drive” direction. Such rotation results in torque being transmitted by thefreewheel 1140 to thesecond side 1144 thereof, applying a torque and causing rotation of thehub 1150 in the “drive” direction. - Conversely, when the
handle actuator 300 moves along theslots retention end hole 440 and toward thedrive end hole 430, though it will be apparent to those of skill in the art that the “free” direction may be in the opposite direction), thehelical member 200 rotates about its longitudinal axis in a second or “free” direction that is opposite the “drive” direction (e.g., counterclockwise, though it will be apparent to those of skill in the art that the “free” direction may instead be clockwise), causing theflexible shaft 1130 and thefirst side 1142 of thefreewheel 1140 to rotate in the “free” direction. However, rotation of thefirst side 1142 of thefreewheel 1140 in the “free” direction causes thefreewheel 1140 to disengage from applying a torque to thesecond side 1144 thereof, allowing thesecond side 1144 and thehub 1150 to continue to move in the “drive” direction. Thus, while thehandle actuator 300 is moved back and forth along theslots hub 1150 is driven only in one direction. - In some embodiments, a drive mechanism including a helical drive also includes a control mechanism that is operable to selectively allow the helical drive to be driven only in one direction (e.g., to allow an actuator to generate torque when moved in a first direction while moving freely without generating torque when moved in an opposing second direction). In some embodiments, such a control mechanism is incorporated into a system using a negative helical form such as that shown in
FIGS. 6A-6D .FIGS. 22-38 show ahelical drive system 2200 including anexemplary control mechanism 2300. Thehelical drive system 2200 has alongitudinal axis 2205. Thehelical drive system 2200 includes ahelical member 3100, afirst end housing 3200, anend bearing 3300, asecond end housing 3400, and abevel gear 3500. - Referring to
FIG. 23 , a section view of thecontrol mechanism 2300 is shown. Thecontrol mechanism 2300 includes ahandle assembly 2400, ahousing 2500, a bearinghousing 2600, a bearingcontrol sleeve 2700, ahelical sleeve 2800,bearings spacers - Referring now to
FIG. 24 , an exploded view of thehandle assembly 2400 is shown. Thehandle assembly 2400, when assembled, defines a handle axis 2402 (seeFIG. 23 ). In some embodiments, thehandle assembly 2400 includes anouter handle 2410, aninner handle 2440, and acam mover 2470. In some embodiments, theouter handle 2410 includes a generallycylindrical handle portion 2412 defining an outergripping surface 2414 and abore 2416 sized and shaped to receive theinner handle 2440. In some embodiments, theouter handle 2410 incorporates other control elements (e.g., a brake control) therein. In some embodiments, theinner handle 2440 includes a generallycylindrical handle portion 2442 sized and shaped to be received within thebore 2416 of theouter handle 2410, a mountingportion 2444, and abore 2446 sized and shaped to receive thecam mover 2470. In some embodiments, the mountingportion 2444 includes holes 2448 that are sized and shaped to receive bolts to mount and secure theinner handle 2440 to thehousing 2500. In some embodiments, a slot 2450 extends through thehandle portion 2442 of theinner handle 2440. thecam mover 2470 includes a generallycylindrical handle portion 2472 configured to be received within thebore 2446 of theinner handle 2440, a generally disc-shapedcam interface portion 2474 positioned at an end of thehandle portion 2472 so as to project beyond thebore 2446 of theinner handle 2440, and acam slot 2476 extending through thecam interface portion 2474. In some embodiments, theouter handle 2410 is attached to thecam mover 2470 by a screw that is secured to thehandle portion 2412 of theouter handle 2410, passes through the slot 2450 of theinner handle 2410, and is secured to thehandle portion 2472 of thecam mover 2470. As a result of such attachment of theouter handle 2410 to thecam mover 2470, when a user grips thegripping surface 2414 of theouter handle 2410 and rotates theouter handle 2410 about thehandle axis 2402, thecam mover 2470 will rotate identically about thehandle axis 2402, while theinner handle 2440 will remain stationary. In some embodiments, rather than including a three-piece handle assembly 2400 as described above, thehelical drive system 2200 includes thehandle assembly 2400 having fewer or more pieces, or includes a single-piece handle operable in a similar manner to thehandle assembly 2400 described herein. - In some embodiments, the
outer handle 2410 comprises a metal. In some embodiments, the metal is an alloy. In some embodiments, the alloy is an aluminum or steel alloy. In some embodiments, the aluminum alloy is an aluminum alloy including silicon and magnesium. In some embodiments, the aluminum alloy is a 6000-series aluminum alloy. In some embodiments, the aluminum alloy is 6061 aluminum. In some embodiments, theinner handle 2440 comprises a metal. In some embodiments, the metal is one of the metals referenced above with respect to theouter handle 2410. In some embodiments, thecam mover 2470 comprises a metal. In some embodiments, the metal is one of the metals referenced above with respect to theouter handle 2410. - Referring now to
FIGS. 25A and 25B , a perspective view and a section view, respectively, of thehousing 2500 are shown. Thehousing 2500 has a hollow generallycylindrical body 2502 centered around a longitudinal axis 2550. Thebody 2502 that tapers to generally disc-shapedends ends holes round projection 2512 extends from a first side of thebody 2502. Acircular hole 2514 is centered in theprojection 2512 and is contiguous with the hollow center of thebody 2502. Aslide support 2518 extends from a second side of thebody 2502 opposite theprojection 2512. Abore 2520 extends through theslide support 2518 and is oriented parallel to the longitudinal axis 2550. In some embodiments, thebore 2520 supports a sliding bushing therein. In some embodiments, the sliding bushing comprises polyoxymethylene, polytetrafluoroethylene (“PTFE”), ultra high molecular weight polyethylene (“UHMWPE”), nylon, or polycarbonate. Thehollow body 2502 includes aninternal cavity 2522 defining aninner surface 2524. In some embodiments, thehousing 2500 comprises a metal. In some embodiments, the metal is one of the metals referenced above with respect to theouter handle 2410. - Referring now to
FIG. 26 , a perspective view of the bearinghousing 2600 is shown. The bearinghousing 2600 has a generallycylindrical body 2602 with abore 2604 extending therethrough. Thebody 2602 is sized and shaped to be positioned within theinternal cavity 2522 of thehousing 2500 as shown inFIG. 23 .Supports FIG. 23 ) project from thebody 2602. Thesupports body 2602, and are spaced about the circumference of thebody 2602. In some embodiments, thesupports inner surface 2524 of thehousing 2500, thereby maintaining thebore 2604 of the bearinghousing 2600 in alignment with thecircular holes housing 2500. Acam pin 2620 projects from thesupport 2612. Thecam pin 2620 is sized and shaped to be received within thecam slot 2476 of thecam mover 2470. In some embodiments, the bearinghousing 2600 comprises a metal. In some embodiments, the metal is one of the metals referenced above with respect to theouter handle 2410. In some embodiments, thesupports housing 2600. In some embodiments, thesupports - Referring now to
FIG. 27 , a perspective view of the bearingcontrol sleeve 2700 is shown. The bearingcontrol sleeve 2700 has a generallycylindrical body 2702 having abore 2704 extending therethrough. Thebody 2702 is sized and shaped to be received within thebore 2604 of the bearinghousing 2600 as shown inFIG. 23 . Thebody 2702 has acentral portion 2706 having a first outside diameter, andend portions control sleeve 2700 comprises a metal. In some embodiments, the metal is one of the metals referenced above with respect to theouter handle 2410. - Referring now to
FIG. 28 , a perspective view of thehelical sleeve 2800 is shown. In some embodiments, thehelical sleeve 2800 comprises polyoxymethylene. In some embodiments, thehelical sleeve 2800 comprises PTFE, UHMWPE, nylon, polycarbonate, or another polymer possessing sufficiently high strength, low friction, and anti-galling properties to perform as will be described hereinafter. In some embodiments, thehelical sleeve 2800 comprises a metal having sufficiently high strength, low-friction, and anti-galling properties to perform as will be described hereinafter, such as a Babbitt metal or a bronze alloy. Thehelical sleeve 2800 has a generallycylindrical body 2802 that is sized and shaped to be received within thebore 2704 of the bearingcontrol sleeve 2700 as shown inFIG. 23 , in a manner such that the bearingcontrol sleeve 2700 and thehelical sleeve 2800 rotate together about thelongitudinal axis 2205 of thedrive system 2200. In some embodiments, thehelical sleeve 2800 is secured to thebearing control sleeve 2700 by one or more of a press fit, an adhesive, and/or a key (e.g., a kay comprising a carbon steel alloy, such as grade 1018 or grade 1045 carbon steel). Thehelical sleeve 2800 has abore 2804 extending through thebody 2802 andinternal threads 2806 projecting inwardly into thebore 2804. Thebore 2804 andthreads 2806 are sized and shaped to matingly receive thehelical shaft 3100 as will be discussed in further detail hereinafter. - Referring now to
FIG. 29 , thebearing 2900 is shown. In some embodiments, thebearing 2900 is a one-way needle roller bearing having a sleeve 2910 and internal rollers 2920. In some embodiments, thebearing 2900 is configured to allow free rotation of the rollers 2920 in one direction and to prevent rotation of the rollers 2920 in an opposite second direction. In some embodiments, thebearing 2900 is the one-way needle roller bearing commercialized under the trade name HF3520 by NationSkander California Corporation of Anaheim, California. In some embodiments, thebearing 2950 is a one-way needle roller bearing having a sleeve 2960 and internal rollers 2970. In some embodiments, the bearing 2960 is configured to allow free rotation of the rollers 2970 in one direction and to prevent rotation of the rollers 2970 in an opposite second direction. In some embodiments, thebearing 2950 is the one-way needle roller bearing commercialized under the trade name HF3520 by NationSkander California Corporation of Anaheim, California. In some embodiments, thebearing 2950 is identical to thebearing 2900. - Referring now to
FIG. 30 , thespacer 3000 is shown. In some embodiments, thespacer 3000 is ring-shaped. In some embodiments, thespacer 3000 is sized and shaped to fit around theend portion 2708 of the bearingcontrol sleeve 2700 and to abut theinner surface 2524 of thehousing 2500, thereby supporting the positioning of the bearingcontrol sleeve 2700 within thehousing 2500 in a position and orientation such that thebore 2704 of the bearing control sleeve is aligned with theholes 2508 of thehousing 2500. In some embodiments, thespacer 3050 is sized and shaped to fit around theend portion 2710 of the bearingcontrol sleeve 2700 and to abut theinner surface 2524 of thehousing 2500, thereby supporting the positioning of the bearingcontrol sleeve 2700 within thehousing 2500 in a position and orientation such that thebore 2704 of the bearing control sleeve is aligned with theholes 2510 of thehousing 2500. In some embodiments, thespacer 3050 is identical to thespacer 3000. In some embodiments, thespacers hollow body 2502 includes aninternal cavity 2522 defining aninner surface 2524. - Referring now to
FIG. 31 , thehelical member 3100 is shown. In some embodiments, thehelical member 3100 is generally similar to thehelical member 700 shown inFIGS. 7A-7C . In some embodiments, thehelical member 3100 includes anelongate body 3102 having a “negative”helix 3104 formed therein. In some embodiments, thehelix 3104 is sized and shaped to receive thethreads 2806 of thehelical sleeve 2800. In some embodiments, thehelical member 3100 includes afirst projection 3106 extending from first end thereof and asecond projection 3108 extending from an opposite second end thereof. In some embodiments, thehelical member 3100 includes agear rod 3110 extending from thesecond projection 3108. In some embodiments, thehelical member 3100 is made of formed stainless steel. In some embodiments, thehelical member 3100 is made of a chromium-nickel stainless steel alloy. In some embodiments, thehelical member 3100 is made of type 301 stainless steel. In some embodiments, thehelical member 3100 is made from a cold-rolled bead-blasted stainless steel. In some embodiments, thehelical member 3100 is formed using a three-axis CNC helical forming machine. In some embodiments, thehelical member 3100 is formed using a helix forming machine such as those commercialized by Helix Flight Manufacturing Machines of Auckland, New Zealand. In some embodiments, thehelical member 3100 is formed using a spring forming machine. - Referring now to
FIG. 32 , thefirst end housing 3200 is shown. Thefirst end housing 3200 has a generallyflat body 3202; however, it will be apparent to those of skill in the art that this is only exemplary and other shapes may be appropriate depending on the nature of the device that is to be powered by thedrive system 2200. In some embodiments, thebody 3200 includes afirst hole 3204 and asecond hole 3206. In some embodiments, thefirst end housing 3200 comprises a metal. In some embodiments, the metal is one of the metals referenced above with respect to theouter handle 2410. - Referring now to
FIG. 33 , theend bearing 3300 is shown. In some embodiments, theend bearing 3300 is configured to be received and retained in thehole 3204 of thefirst end housing 3200. In some embodiments, theend bearing 3300 is a roller bearing that is configured to receive and retain therein thefirst projection 3106 of thehelical member 3100, and to allow thehelical member 3100 to rotate freely about thelongitudinal axis 2205 with respect to the first end housing. In some embodiments, theend bearing 3300 is the bearing commercialized as model number 7902A5 by NSK Limited of Tokyo, Japan. - Referring now to
FIG. 34 , thesecond end housing 3400 is shown. In some embodiments, thesecond end housing 3400 includes asolid body 3402 with acavity 3404 formed therein. In some embodiments, thesecond end housing 3400 includes first andsecond holes cavity 3404 through a first side of thebody 3402. In some embodiments, thesecond end housing 3400 includes athird hole 3410 extending from thecavity 3404 through an adjacent second side of thebody 3402. In some embodiments, thefirst hole 3406 is sized and shaped to receive thesecond projection 3108 of thehelical member 3100 and to allow thesecond projection 3108 to rotate within thefirst hole 3406. In some embodiments, thesecond end housing 3400 comprises a metal. In some embodiments, the metal is one of the metals referenced above with respect to theouter handle 2410. - Referring now to
FIG. 35 , thebevel gear 3500 is shown. In some embodiments, thebevel gear 3500 is configured to engage thegear rod 3110 of thehelical member 3100. In some embodiments, thebevel gear 3500 is configured to convey output torque generated by thedrive system 2200, as will be described in detail hereinafter. Referring back toFIG. 34 , in some embodiments, thebevel gear 3500 engages another gear connected to a drive member that extends through thethird hole 3410 of thesecond end housing 3400. In some embodiments, thebevel gear 3500 comprises a metal. In some embodiments, thebevel gear 3500 comprises a carbon steel. In some embodiments, thebevel gear 3500 comprises agrade 1144 or grade 1177 carbon steel alloy. - Referring now to
FIG. 36 , theslider rod 3600 is shown. In some embodiments, theslider rod 3600 has afirst end 3602 and an oppositesecond end 3604. In some embodiments, thefirst end 3602 is configured to be received by thesecond hole 3206 of thefirst end housing 3200 and retained therein in a fixed and non-moving engagement. In some embodiments, thesecond end 3604 is configured to be received by thesecond hole 3408 of thesecond end housing 3400 and retained therein in a fixed and non-moving engagement. In some embodiments, theslider rod 3600 comprises a metal. In some embodiments, the metal is one of the metals referenced above with respect to theouter handle 2410. - Referring now to
FIGS. 23, 26, and 29 , thebore 2604 of the bearinghousing 2600 is sized and shaped to securely receive thebearings housing 2600, and thebearings longitudinal axis 2205 of the drive system 2200). In some embodiments, thebearings bore 2604 of the bearinghousing 2600 by a press fit. - Referring now to
FIGS. 23, 27 and 29 , thecentral portion 2706 of the bearingcontrol sleeve 2700 is sized such that thebearings central portion 2706 as shown inFIG. 23 in a manner such that the rollers 2920, 2970 of thebearings central portion 2706 of the bearingcontrol sleeve 2700. As a result, when thebearings FIG. 23 , the bearingcontrol sleeve 2700 can rotate freely in either direction about thelongitudinal axis 2205 with respect to thebearings 2900, 2950 (and, thereby, with respect to the bearing housing 2600). Theend portions control sleeve 2700 are sized such that thebearings end portions respective end portions control sleeve 2700. When the rollers 2920, 2970 contact therespective end portions bearings control sleeve 2700 to rotate freely in one direction about thelongitudinal axis 2205 with respect to thebearings 2900, 2950 (and, thereby, with respect to the bearing housing 2600). Thebearings - For example,
FIG. 37 shows thecontrol system 2300 positioned such that the bearinghousing 2600 and thebearings longitudinal axis 2205 in a direction toward theend portion 2708 of the bearingcontrol sleeve 2700. As a result, the rollers 2920 of thebearing 2900 contact theend portion 2708, while the rollers 2970 of thebearing 2950 remain aligned with, and do not contact, thecentral portion 2706 of the bearingcontrol sleeve 2700. In some embodiments, when thebearing 2900 is positioned in this manner (i.e., with the rollers 2920 contacting the end portion 2708), thecontrol sleeve 2700 is allowed to rotate freely with respect to the bearinghousing 2600 in a first direction about thelongitudinal axis 2205, but is prevented from rotating with respect to the bearinghousing 2600 in a second direction about thelongitudinal axis 2205. -
FIG. 38 shows thecontrol system 2300 such that the bearinghousing 2600 and thebearings longitudinal axis 2205 in a direction toward theend portion 2710 of the bearingcontrol sleeve 2700. As a result, the rollers 2970 of thebearing 2950 contact theend portion 2710, while the rollers 2920 of thebearing 2900 remain aligned with, and do not contact, thecentral portion 2706 of the bearingcontrol sleeve 2700. In some embodiments, when thebearing 2900 is positioned in this manner (i.e., with the rollers 2970 contacting the end portion 2710), the bearingcontrol sleeve 2700 is allowed to rotate freely with respect to the bearinghousing 2600 in the second direction about the longitudinal axis 2205 (e.g., the direction in which thebearing control sleeve 2700 is constrained from rotation when the bearinghousing 2600 is positioned as shown inFIG. 37 ), but is prevented from rotating with respect to the bearinghousing 2600 in the first direction about the longitudinal axis 2205 (e.g., the direction in which thebearing control sleeve 2700 is constrained from rotation when the bearinghousing 2600 is positioned as shown inFIG. 37 . - Referring now to
FIGS. 23 and 24 , actuation of thehandle assembly 2400 is described. In some embodiments, theouter handle 2410 is positioned such that a user can grip thegripping surface 2414. Thehandle assembly 2400 engages thehousing 2500 in a manner such that the user can grip thegripping surface 2414 and rotate theouter handle 2410 about thehandle axis 2402. Rotation of theouter handle 2410 causes corresponding rotation of thecam mover 2470 about thehandle axis 2402. When thecam mover 2470 rotates about thehandle axis 2402, thecam slot 2476 is repositioned, thereby acting as a cam in cooperation with thecam pin 2620 and driving movement of the bearinghousing 2600 along thelongitudinal axis 2205. - Referring now to
FIGS. 23, 24, 37, and 38 , thehandle assembly 2400 and the bearinghousing 2600 are configured such that thehandle assembly 2400 can be positioned in a “neutral” position, can be rotated about thehandle axis 2402 in a first direction reach a “forward” position, and can be rotated about thehandle axis 2402 in an opposing second direction to reach a “reverse” position. In the “neutral” position, as shown inFIG. 23 , the bearinghousing 2600 is positioned such that thebearings central portion 2706 of the bearingcontrol sleeve 2700, as a result of which thebearing control sleeve 2700 can rotate freely in either direction about thelongitudinal axis 2205 with respect to the bearinghousing 2600. In the “forward” position, as shown inFIG. 37 , the bearinghousing 2600 is positioned such that thebearing 2900 is aligned with theend portion 2708 of the bearingcontrol sleeve 2700 and thebearing 2950 is aligned with thecentral portion 2706 of the bearingcontrol sleeve 2700, as a result of which thebearing control sleeve 2700 can rotate freely in a first direction about thelongitudinal axis 2205 with respect to the bearinghousing 2600, but is prevented from rotating in an opposing second direction about thelongitudinal axis 2205 with respect to the bearinghousing 2600. In the “reverse” position, as shown inFIG. 38 , the bearinghousing 2600 is positioned such that thebearing 2950 is aligned with theend portion 2710 of the bearingcontrol sleeve 2700 and thebearing 2900 is aligned with thecentral portion 2706 of the bearingcontrol sleeve 2700, as a result of which thebearing control sleeve 2700 can rotate freely in the second direction about thelongitudinal axis 2205 with respect to the bearinghousing 2600, but is prevented from rotating in the first direction about thelongitudinal axis 2205 with respect to the bearinghousing 2600. As a result, rotation of thehandle assembly 2400 about the handle axis controls the direction in which thebearing control sleeve 2700 is allowed to rotate. - Referring now to
FIGS. 22 and 23 , thedrive system 2200 and thecontrol system 2300 are described. In some embodiments, theend bearing 3300 is received in thefirst hole 3204 of thefirst end housing 3200. In some embodiments, thefirst end 3106 of thehelical member 3100 is received by theend bearing 3300. In some embodiments, thefirst end 3602 of theslider rod 3600 is received and retained in thesecond hole 3204 of thefirst end housing 3200. In some embodiments, thecontrol system 2300, assembled as shown inFIG. 23 , engages thehelical member 3100 and theslider rod 3600 by receiving thehelical member 3100 within thebore 2704 of thehelical sleeve 2800 and by receiving theslider rod 3600 within thebore 2520 of thehousing 2500. In some embodiments, thesecond end housing 3400 is engaged to thedrive system 2200 by passing thesecond projection 3108 of thehelical member 3100 through thefirst hole 3406 of thesecond end housing 3400, and by fixing thesecond end 3604 of theslider rod 3600 in thesecond hole 3408 of thesecond end housing 3400. In some embodiments, thehelical member 3100 is secured to thesecond end housing 3400 by engaging thebevel gear 3500 to thegear rod 3110 of thehelical member 3100. In some embodiments, with thedrive system 2200 assembled as described above, thecontrol system 2300 can slide freely along theslider rod 3600. In some embodiments, motion of thecontrol system 2300 with respect to thehelical member 3100 operates as described hereinafter. - Referring to
FIGS. 22 and 23 , as described above, when thehandle assembly 2400 is in the “neutral” position as shown inFIG. 22 , the bearingcontrol sleeve 2700, and thehelical sleeve 2800 received fixedly therein, are allowed to rotate freely about thelongitudinal axis 2205 with respect to the bearinghousing 2600. Consequently, when force is applied to thehandle assembly 2400 so as to move thecontrol system 2300 in either direction along thelongitudinal axis 2205, theinternal threads 2806 of thehelical sleeve 2800 are forced against thehelix 3104 of thehelical member 3100. Because the bearingcontrol sleeve 2700 and thehelical sleeve 2800 are not constrained from rotation about thelongitudinal axis 2205, such force against thehelix 3104 causes thebearing control sleeve 2700 and thehelical sleeve 2800 to rotate about thelongitudinal axis 2205 with respect both to thehelical member 3100 and to the bearinghousing 2600, enabling theinternal threads 2806 of thehelical sleeve 2800 to rotate within thehelix 3104 of thehelical member 3100. As a result, thehelical member 3100 is not rotated about thelongitudinal axis 2205, and no torque is generated at thebevel gear 3500 in either direction. - Referring to
FIGS. 22 and 37 , as described above, when thehandle assembly 2400 is in the “forward” position as shown inFIG. 37 , the bearingcontrol sleeve 2700, and thehelical sleeve 2800 received fixedly therein, are allowed to rotate freely about thelongitudinal axis 2205 in a first direction with respect to the bearinghousing 2600, but are constrained from rotating about thelongitudinal axis 2205 in an opposite second direction with respect to the bearing housing due to the engagement of thebearing 2900 with theend 2708 of the bearingcontrol sleeve 2700. Consequently, when force is applied to thehandle assembly 2400 so as to move thecontrol system 2300 in a first direction along thelongitudinal axis 2205, the first direction corresponding to the first direction of rotation of the bearingcontrol sleeve 2700 and thehelical sleeve 2800, the bearingcontrol sleeve 2700 and thehelical sleeve 2800 rotate in the first direction about thelongitudinal axis 2205 as described above with reference to the “neutral” position, thehelical member 3100 is not rotated about thelongitudinal axis 2205, and no torque is generated at thebevel gear 3500. Conversely, when force is applied to thehandle assembly 2400 so as to move thecontrol system 2300 in a second direction along thelongitudinal axis 2205, the second direction being opposite the first direction and corresponding to the second direction of rotation of the bearingcontrol sleeve 2700 and thehelical sleeve 2800, theinternal threads 2806 of thehelical sleeve 2800 are forced against thehelix 3104 of the helical member. However, due to the engagement of thebearing 2900 with theend 2708 of the bearingcontrol sleeve 2700, thehelical sleeve 2800 and the bearingcontrol sleeve 2700 are not allowed to rotate in the second direction with respect to the bearinghousing 2600. As a result, the applied force causes thehelical member 3100 to rotate about thelongitudinal axis 2205 in order for thehelix 3104 to remain in engagement with theinternal threads 2806 of thehelical sleeve 2800 as the helical sleeve 2800 (along with the remainder of the control system 2300) moves along the longitudinal axis, thereby generating a torque at thebevel gear 3500. Consequently, when thehandle assembly 2400 is in the “forward” position, linear motion of thecontrol system 2300 in the first direction does not generate a torque at thebevel gear 3500, but linear motion of thecontrol system 2300 in the second direction generates a “forward” torque at thebevel gear 3500. - Referring to
FIGS. 22 and 38 , as described above, when thehandle assembly 2400 is in the “reverse” position as shown inFIG. 38 , the bearingcontrol sleeve 2700, and thehelical sleeve 2800 received fixedly therein, are allowed to rotate freely about thelongitudinal axis 2205 in a the second direction with respect to the bearinghousing 2600, but are constrained from rotating about thelongitudinal axis 2205 in the first direction with respect to the bearing housing due to the engagement of thebearing 2950 with theend 2710 of the bearingcontrol sleeve 2700. Consequently, when force is applied to thehandle assembly 2400 so as to move thecontrol system 2300 in the second direction along thelongitudinal axis 2205, the second direction corresponding to the second direction of rotation of the bearingcontrol sleeve 2700 and thehelical sleeve 2800, the bearingcontrol sleeve 2700 and thehelical sleeve 2800 rotate in the second direction about thelongitudinal axis 2205 as described above with reference to the “neutral” position, thehelical member 3100 is not rotated about thelongitudinal axis 2205, and no torque is generated at thebevel gear 3500. Conversely, when force is applied to thehandle assembly 2400 so as to move thecontrol system 2300 in the first direction along thelongitudinal axis 2205, the first direction being opposite the second direction and corresponding to the first direction of rotation of the bearingcontrol sleeve 2700 and thehelical sleeve 2800, theinternal threads 2806 of thehelical sleeve 2800 are forced against thehelix 3104 of the helical member. However, due to the engagement of thebearing 2950 with theend 2710 of the bearingcontrol sleeve 2700, thehelical sleeve 2800 and the bearingcontrol sleeve 2700 are not allowed to rotate in the first direction with respect to the bearinghousing 2600. As a result, the applied force causes thehelical member 3100 to rotate about thelongitudinal axis 2205 in order for thehelix 3104 to remain in engagement with theinternal threads 2806 of thehelical sleeve 2800 as the helical sleeve 2800 (along with the remainder of the control system 2300) moves along the longitudinal axis, thereby generating a torque at thebevel gear 3500 that is opposite to the torque generated as discussed above with reference toFIG. 37 . Consequently, when thehandle assembly 2400 is in the “reverse” position, linear motion of thecontrol system 2300 in the second direction does not generate a torque at thebevel gear 3500, but linear motion of thecontrol system 2300 in the first direction generates a “reverse” torque at thebevel gear 3500. - Summarizing the above discussion of the
drive system 2200 and thecontrol system 2300, thehandle assembly 2400 can be rotated by a user to place thecontrol system 2300 in either a “neutral” position, a “forward” position, or a “reverse” position. When thecontrol system 2300 is in the “neutral” position, the user can apply force to the handle assembly to move thecontrol system 2300 along thehelical member 3100 in either direction, and motion in either direction results in free movement of thecontrol system 2300 without generation of any output torque at thebevel gear 3500. When thecontrol system 2300 is in the “forward” position, the user can apply force to the handle to move thecontrol system 2300 along thehelical member 3100 in a first direction, and such motion generates an output torque in a first (e.g., forward) torque direction at thebevel gear 3500. However, while thecontrol system 2300 is in the “forward” position, the user can apply force to the handle to move thecontrol system 2300 along thehelical member 3100 in a second direction that is opposite the first direction, and such motion generates no output torque at thebevel gear 3500. When thecontrol system 2300 is in the “reverse” position, the user can apply force to the handle to move thecontrol system 2300 along thehelical member 3100 in the second direction, and such motion generates an output torque in a second (e.g., reverse) torque direction that is opposite the first torque direction at thebevel gear 3500. However, while thecontrol system 2300 is in the “reverse” position, the user can apply force to the handle to move thecontrol system 2300 along thehelical member 3100 in the first direction, and such motion generates no output torque at thebevel gear 3500. In some embodiments, thedrive system 2200 is suitable for use in human-powered devices, such as a wheelchair, in which a user may wish to be able to apply a linear force to thereby generate output torque in two opposed directions. - While a number of embodiments of the present invention have been described, it is understood that these embodiments are illustrative only, and not restrictive, and that many modifications may become apparent to those of ordinary skill in the art. For example, all dimensions discussed herein are provided as examples only, and are intended to be illustrative and not restrictive.
Claims (12)
1. A device, comprising:
a frame;
an actuator attached to the frame and slidaby movable with respect to the frame along a linear axis, and
a helical member positioned within the frame and rotatably movable with respect to the frame about a helical axis of the helical member, wherein the helical axis is parallel to the linear axis,
wherein the actuator and the helical member are configured to cooperate with one another such that (a) motion of the actuator along the linear axis in a first linear direction causes corresponding rotation of the helical member about the helical axis in a first rotational direction and (b) motion of the actuator along the linear axis in a second linear direction that is opposite the first linear direction causes corresponding rotation of the helical member about the helical axis in a second rotational direction that is opposite the first rotational direction.
2. The device of claim 1 , wherein the at least one follower bearing includes a first follower bearing positioned to a first side of the helical member and a second follower bearing positioned to a second side of the helical member that is opposite the first side of the helical member.
3. The device of claim 1 , further comprising at least one plain bearing positioned on a portion of the frame so as to reduce friction between the helical member and the frame when the helical member rotates about the helical axis.
4. The device of claim 1 , wherein the helical member has a helical pitch of between 85 millimeters and 95 millimeters.
5. The device of claim 1 , wherein the helical member has a lead angle of between 24 degrees and 27 degrees.
6. The device of claim 1 , wherein the helical member has a pitch diameter of between 48 millimeters and 52 millimeters.
7. A system, comprising:
a frame;
an actuator attached to the frame and slidaby movable with respect to the frame along a linear axis,
a helical member positioned within the frame and rotatably movable with respect to the frame about a helical axis of the helical member, wherein the helical axis is parallel to the linear axis; and
a drive shaft coupled to the helical member, wherein the drive shaft has a longitudinal axis,
wherein the actuator and the helical member are configured to cooperate with one another such that (a) motion of the actuator along the linear axis in a first linear direction causes corresponding rotation of the helical member about the helical axis in a first rotational direction and (b) motion of the actuator along the linear axis in a second linear direction that is opposite the first linear direction causes corresponding rotation of the helical member about the helical axis in a second rotational direction that is opposite the first rotational direction, and
wherein the drive shaft is coupled to the helical member in a manner such that (a) rotation of the helical member about the helical axis in the first rotational direction causes corresponding rotation of the drive shaft about the longitudinal axis in a first rotational direction and (b) rotation of the helical member about the helical axis in the second rotational direction causes corresponding rotation of the drive shaft about the longitudinal axis in a second rotational direction that is opposite the first rotational direction of the longitudinal axis.
8. The system of claim 7 , wherein the helical member has a helical pitch of between 85 millimeters and 95 millimeters.
9. The system of claim 7 , wherein the helical member has a lead angle of between 24 degrees and 27 degrees.
10. The system of claim 7 , wherein the helical member has a pitch diameter of between 48 millimeters and 52 millimeters.
11. The system of claim 7 , wherein the drive shaft is coupled to drive system of a vehicle in a manner so as to propel the vehicle.
12. The system of claim 11 , wherein the vehicle is a wheelchair.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US18/305,179 US20230383822A1 (en) | 2019-07-12 | 2023-04-21 | Helical drive mechanism and handle mechanism for wheelchair with helical drive |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201962873734P | 2019-07-12 | 2019-07-12 | |
US202062965051P | 2020-01-23 | 2020-01-23 | |
US16/925,681 US11635124B2 (en) | 2019-07-12 | 2020-07-10 | Helical drive mechanism and handle mechanism for wheelchair with helical drive |
US18/305,179 US20230383822A1 (en) | 2019-07-12 | 2023-04-21 | Helical drive mechanism and handle mechanism for wheelchair with helical drive |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US16/925,681 Continuation US11635124B2 (en) | 2019-07-12 | 2020-07-10 | Helical drive mechanism and handle mechanism for wheelchair with helical drive |
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Publication Number | Publication Date |
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US20230383822A1 true US20230383822A1 (en) | 2023-11-30 |
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US16/925,681 Active 2041-07-01 US11635124B2 (en) | 2019-07-12 | 2020-07-10 | Helical drive mechanism and handle mechanism for wheelchair with helical drive |
US18/305,179 Pending US20230383822A1 (en) | 2019-07-12 | 2023-04-21 | Helical drive mechanism and handle mechanism for wheelchair with helical drive |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
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US16/925,681 Active 2041-07-01 US11635124B2 (en) | 2019-07-12 | 2020-07-10 | Helical drive mechanism and handle mechanism for wheelchair with helical drive |
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US (2) | US11635124B2 (en) |
EP (1) | EP3997362A4 (en) |
JP (1) | JP2022540485A (en) |
KR (1) | KR20220152991A (en) |
CN (1) | CN114651141A (en) |
AU (1) | AU2020312798A1 (en) |
CA (1) | CA3146495A1 (en) |
MX (1) | MX2022000547A (en) |
WO (1) | WO2021009560A1 (en) |
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Publication number | Priority date | Publication date | Assignee | Title |
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CN116733919B (en) * | 2023-08-09 | 2023-10-13 | 成都博森数智科技有限公司 | Linear reciprocating motion structure and massage product |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6241565B1 (en) * | 1996-12-23 | 2001-06-05 | Helixsphere Technologies, Inc. | Helical drive human powered boat |
US6199884B1 (en) * | 1996-12-23 | 2001-03-13 | 7444353 Alberta Ltd. | Helical drive bicycle |
WO1998044783A2 (en) * | 1997-04-07 | 1998-10-15 | Helical Dynamics International Inc. | Helical drive fishing reels |
CA2286029C (en) * | 1997-04-07 | 2006-10-24 | Helical Dynamics International Inc. | Helical drive wheelchair |
WO1998045621A1 (en) * | 1997-04-07 | 1998-10-15 | Helical Dynamics International Inc. | In-line multi-gear transmission system and multi-gear wheel hub in a helical drive system |
US20140123789A1 (en) * | 2012-11-05 | 2014-05-08 | Boston Dynamics, Inc. | Actuator |
US9303738B1 (en) * | 2013-12-31 | 2016-04-05 | James Bombardo | Arrangement and method for guiding a load in a linear movement |
JP2015159985A (en) * | 2014-02-27 | 2015-09-07 | 住友ゴム工業株式会社 | wheelchair |
JP2015216951A (en) * | 2014-05-14 | 2015-12-07 | イー・アーム株式会社 | User operable driving tool for wheelchair |
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2020
- 2020-07-10 AU AU2020312798A patent/AU2020312798A1/en not_active Abandoned
- 2020-07-10 WO PCT/IB2020/000573 patent/WO2021009560A1/en unknown
- 2020-07-10 KR KR1020227004544A patent/KR20220152991A/en not_active Application Discontinuation
- 2020-07-10 EP EP20839669.7A patent/EP3997362A4/en active Pending
- 2020-07-10 US US16/925,681 patent/US11635124B2/en active Active
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WO2021009560A8 (en) | 2021-08-19 |
US11635124B2 (en) | 2023-04-25 |
WO2021009560A1 (en) | 2021-01-21 |
EP3997362A1 (en) | 2022-05-18 |
US20210010575A1 (en) | 2021-01-14 |
KR20220152991A (en) | 2022-11-17 |
CA3146495A1 (en) | 2021-01-21 |
MX2022000547A (en) | 2022-04-20 |
CN114651141A (en) | 2022-06-21 |
JP2022540485A (en) | 2022-09-15 |
AU2020312798A1 (en) | 2022-02-24 |
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