Classifications

• • 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
  • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
  • F16H25/20—Screw 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
  • A61G5/10—Parts, details or accessories
  • A61G5/1056—Arrangements for adjusting the seat
• • 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
  • A61G7/00—Beds specially adapted for nursing; Devices for lifting patients or disabled persons
  • A61G7/002—Beds specially adapted for nursing; Devices for lifting patients or disabled persons having adjustable mattress frame
  • A61G7/018—Control or drive mechanisms
• • 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
  • F16H19/00—Gearings comprising essentially only toothed gears or friction members and not capable of conveying indefinitely-continuing rotary motion
  • F16H19/02—Gearings comprising essentially only toothed gears or friction members and not capable of conveying indefinitely-continuing rotary motion for interconverting rotary or oscillating motion and reciprocating motion
  • F16H19/04—Gearings comprising essentially only toothed gears or friction members and not capable of conveying indefinitely-continuing rotary motion for interconverting rotary or oscillating motion and reciprocating motion comprising a rack
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T74/00—Machine element or mechanism
  • Y10T74/18—Mechanical movements
  • Y10T74/18568—Reciprocating or oscillating to or from alternating rotary
  • Y10T74/18576—Reciprocating or oscillating to or from alternating rotary including screw and nut
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T74/00—Machine element or mechanism
  • Y10T74/19—Gearing
  • Y10T74/1956—Adjustable
  • Y10T74/19565—Relative movable axes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T74/00—Machine element or mechanism
  • Y10T74/20—Control lever and linkage systems
  • Y10T74/20012—Multiple controlled elements
  • Y10T74/20018—Transmission control
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T74/00—Machine element or mechanism
  • Y10T74/20—Control lever and linkage systems
  • Y10T74/20012—Multiple controlled elements
  • Y10T74/20018—Transmission control
  • Y10T74/2003—Electrical actuator
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T74/00—Machine element or mechanism
  • Y10T74/20—Control lever and linkage systems
  • Y10T74/20012—Multiple controlled elements
  • Y10T74/20018—Transmission control
  • Y10T74/2014—Manually operated selector [e.g., remotely controlled device, lever, push button, rotary dial, etc.]

Definitions

• Various types of braking mechanisms have also been proposed to bring a rotating system to a stop by applying a frictional force to the rotating device.
• an actuator may be used to tighten a metal component, which runs around a rotating drum in the event of a failure in the rotation of the drum.
• a disc brake may be located on a rotating shaft and a calliper may be used to provide friction to the disc to slow and eventually stop the shaft from rotating.
• friction based braking systems require control systems to activate the braking means when a sensor has detected a reason why the rotating system should be prevented from rotating.
• the present invention provides a rotary system with a system which can prevent rotary output when there is a failure in the rotary system such that it would not be providing a desired/expected output.
• the rotation of the drive shaft results in proportional movement of the pin and proportional rotation of the output shaft.
• the arrestor path is provided with a self-locking means.
• the arrestor path has an input coupled to the drive shaft and an output coupled to the pin.
• Application of force to the pin does not result in movement of the pin due to its coupling with the output end of the arrester path, and therefore does not result in movement of the output shaft. This ensures that in the absence of drive to the input of the arrestor path, the pin will not move and therefore the output shaft will not rotate.
• the transmission path could be provided with a self-locking means.
• the guideway is a channel in the output shaft.
• the channel may be a through channel which projects completely through the output shaft.
• the channel may be a blind channel which projects partially into the output shaft. In either case, when the movement of the pin is not synchronised with the rotation of the output shaft, the pin will abut against a side wall of the channel to limit the further rotation of the output shaft.
• the pin projects into/through a guide which is generally aligned with the pin path.
• the guide is fixed with respect to the pin path and may be integral with a casing housing the system.
• the guide acts to guide the pin along its pin path, as well as helping to prevent the pin from being moved out of the pin path, for example due to rotation of the output shaft. More specifically, where the output shaft is rotating but is not synchronised with the movement of the pin the side walls of the guideway of the output shaft will abut against the pin. The moment carried by the output shaft may be relatively large such that it imposes a force on the pin.
• the guides reduce the unsupported length of the pin and hence allow a smaller pin to be used and share the load with the casing. Further, the use of guides allows the characteristics of the system to be altered, and assists in isolating load and helps prevent the applied force from the output shaft from being transmitted to the connection between the pin and the arrestor path.
• components of the system may be shared between arrestor paths. Sharing of components can minimise the complexity of the system as well as reducing cost and spacing requirements. However in some cases, it may be preferable for components of the system to be separately provided for each arrestor path. For example, where the system includes a self-locking means, it may be preferable for each arrestor path to be separately provided with a self-locking means.
• Figure 4 shows a schematic view of a second embodiment of a system having a rotary output
• Figure 7 shows a side view of a fourth embodiment of a system having a rotary output
• Figure 9 shows a plan view of the system of figure 8.
• Figure 10 shows a plan view of a sixth embodiment of a system having a rotary output
• Figure 12 shows a plan view of a seventh embodiment of a system having a rotary output.
• Figure 1 shows a schematic view of a first embodiment of a system having a rotary output.
• Figure 2 shows the system of Figure 1 when viewed from the left hand side of Figure 1.
• Figure 3 shows the system of Figure 1 when viewed from the lower side of Figure 1.
• the transmission means 40 is coupled to both the drive shaft 10 and the output shaft 50 such that rotation of the drive shaft 10 results in a proportional rotation of the output shaft 50.
• the transmission means 40 can be any arrangement of gears or other suitable components which can transmit the motion and force of the drive shaft 10 to the output shaft 50.
• the transmission means 40 can convert and/or modify the motion and force transmitted from the drive shaft 10 and apply that modified motion to the output shaft 50 as desired.
• the channel 55 is arranged such that rotation of the output shaft aligns a different portion of the channel with the pin's path.
• the particular geometry of the channel 55 is not shown in Figures 1 to 3 but could have, for example, a generally helical or curved diagonal profile. The geometry will depend upon the expected relationship between the movement of the pin and the rotation of the output shaft.
• the ability of the system to arrest when the two paths come out of synchronisation means that failure of the system to perform as expected will result in the system being prevented from outputting an unexpected and/or undesired rotation.
• This failure does not necessarily have to be a complete failure of one or all of the components, but also includes situations where failure constitutes partial wear of a component in either path.
• the extent to which wear results in the system arresting will be dependent upon how finely calibrated the system is. For example, a system could be made more likely to arrest in the event of minor wear of a component, by narrowing the gap between the surface of the channel 55 and the pin 90.
• a narrow gap would mean that only the slightest deviation from the expected motion of either the pin 90 or output shaft 50, would result in contact between the pin 90 and the surface of the channel 55 and hence the system arresting.
• providing a large gap between the surface of the channel 55 and the pin 90 means that minor, and in some cases insignificant, wear of a component would not alone cause the system to arrest but that cumulative or more significant wear or failure could.
• the drive shaft 10 is meshed with a toothed section 16.
• the toothed section 16 is attached to or integral with a first end of an extension arm 30.
• the second end of the extension arm 30 is meshed with a gear 61 which is, through a series of further gears, meshed with a leadscrew 60.
• a nut 70 attached to the pin 90 is meshed with the leadscrew 60 such that the rotation of the leadscrew 60 causes the translation of the nut 70 and therefore the pin 90 in a direction generally parallel to the axis of the leadscrew 60.
• the toothed section 16 moves linearly in proportion to the rotation of the drive shaft 10, and results in linear movement of the extension arm 30.
• the meshing of the second end of the extension arm 30 with the gear 61 will convert the linear movement of the arm 30 into rotational movement of the gear 61.
• the linear movement of the extension arm 30 is converted into rotational movement of the leadscrew 60. Since leadscrew 60 is meshed with nut 70, rotation of the leadscrew 60 causes linear movement of the nut 70 and hence linear movement of the pin 90 along the longitudinal axis of the leadscrew 60. If the movement of the pin 90 is synchronised with the rotation of the output shaft 50, the pin 90 will then move along its linear path, as the output shaft 50 rotates.
• the leadscrew 60 were merely a track on which the nut 70 and pin 90 were slidably engaged, the force imposed on the pin 90 by the output shaft 50 could cause the pin 90 to slide along the track and hence allow the output shaft 50 to rotate, even if a failure had occurred within the system.
• the nut 70 is threadingly engaged with a self-locking means such as the leadscrew 60, the nut 70 and pin 90 cannot be moved longitudinally by the force from the output shaft 50, since movement of the nut 70 and pin 90 can only be achieved through rotation of the leadscrew 60.
• the pin 90 projects into a guide 80, which is fixed with respect to the pin's path.
• the guide 80 is a channel of a casing housing the system. The guide 80 acts as a means for guiding the pin 90 along its path of travel, as well as helping to prevent the pin 90 from being moved out of the pin path, for example due to rotation of the output shaft 50.
• the output shaft 50 is rotating but is not synchronised with the movement of the pin 90 the side walls of the channel 55 will abut against the pin 90.
• the moment carried by the output shaft 50 may be relatively large such that it imposes a force on the pin 90.
• the guides 80 reduce the unsupported length of the pin 90 and hence allow a smaller pin to be used and share the load with the casing. Further, the use of guides 80 allows the characteristics of the system to be altered, and assist in isolating load and help prevent the applied force from the output shaft 5 from being transmitted to the connection between the pin 90 and the arrestor path.
• the width of the guide 80, and hence the gap/distance between its surfaces and the surface of the pin 90 can be varied. Small gaps or distances would mean that only the slightest change in the expected motion or angle of the pin 90 would result in contact between the surfaces.
• a further means for arresting the system in the event of a failure is to form or coat the surfaces of the guide 80 with a material which is softer than the pin 90 such that it can be deformed by the pin 90, but which is sufficiently strong such that the deformed guide 80 will act to inhibit the movement of the pin 90 and thereby assist in arresting the system.
• the arrestor can be used to prevent the output shaft 50 from rotating beyond a certain range. This can be achieved by limiting the extent of the pin path.
• the extent of the pin path can be limited by, for example, limiting the length of the channel 55, by limiting the length of the leadscrew 60 or by limiting the amount of linear motion the arrestor path is able to provide the pin 90 with.
• Figures 1 to 3 show a rotating system which has one arrestor path for preventing rotation when the system is failing to perform as expected.
• the rotating system may have more than one arrestor path for arresting the rotation of the system.
• each arrestor path in order for the system to operate correctly and provide output, each arrestor path must be itself synchronised with respect to the transmission path and accordingly synchronised with respect to each other.
• Figure 4 shows a schematic view of a second embodiment of a system having a rotary output.
• the rotating system shown is similar to that shown in Figure 1 , but with the notable exception that the system of Figure 4 includes a second arrestor path.
• first and second gears 161 A, 161 B may instead be located at one end of their respective leadscrews 160A, 160B without needing to be meshed to their respective leadscrews 160A, 160B via a series of gears.
• Figure 5 shows a side view of the system of Figure 4.
• an elongated span member 175 couples the first nut 170A to the second nut 170B.
• the first end of the elongated span member 175 is attached to or integral with the first nut 170A, whilst the second end of the elongated member 175 is attached to or integral with the second nut 170B.
• a pin 190 is attached to or integral with the span member 175.
• the pin 190 projects into/through a channel 155 or other guideways within an output shaft 150 as described with respect to the first embodiment.
• the pin 190 can also project into a guide 80 which is fixed with respect to and generally aligned with the pin path.
• the channel 155 has a generally curved diagonal profile.
• the channel 155 could have any other suitable profile which would allow the pin 190 to move as expected along the pin path as the shaft 150 is rotated.
• the profile of the channel 155 is dependent on the particular pin path and the intended rotation of the output shaft 50.
• the channel 155 could be helical or s-shaped, a straight or curved diagonal, or a parabola or combinations thereof.
• the transmission path includes a transmission means 140 which is coupled to both the drive shaft 110 and the output shaft 150 such that rotation of the drive shaft 110 results in rotation of the output shaft 150.
• the transmission means 140 may be an arrangement of gears or other suitable components, which can convert and modify the motion/force transmitted from the drive shaft 110 as desired, and which can apply that modified motion/force to the output shaft 150.
• the linear movement of the pin 190 must be synchronised with the rotation of the output shaft 150 such the portion of the channel 155 aligned with the path corresponds with the position of the pin 190, for any given rotation of the drive shaft 110.
• the portion of the guideway 155 aligned with the path will not correspond with the position of the pin 190 such that the pin will abut against a sidewall of the channel 155 to limit the further rotation of the output shaft 150.
• the first toothed section 116A meshes to a radially opposite surface of the drive shaft 110 to that of the second toothed section 116B. Accordingly, rotation of the drive shaft 110 results in the toothed sections 116A, 116B and their corresponding extension arms 130A, 130B being driven in linearly opposite directions.
• either one of the arrestor paths may be provided with an additional gear, or one of the leadscrews 160A, 160B may be provided with a clockwise thread, whilst the other is provided with an anti-clockwise thread and/or the relative position and configuration of the arms 130A and 130B can be arranged to provide the necessary operational output. If the leadscrews 160A, 160B drive the respective nuts 170A 1 170B at a different rate, the span member 175 will twist so that it is no longer perpendicular to the leadscrews 160A, 160B. This will cause the nuts 170A, 170B to jam onto the thread of the leadscrews 160A, 160B.
• Figure 6 shows a plan view of a third embodiment of a system having a rotary output.
• the arrestor paths share a component, namely a leadscrew 260.
• a first extension arm 230A of the first arrestor path meshes with a first gear 261 A located at a first end of the leadscrew 260, whilst a second extension arm 230B of the second arrestor path meshes with a second gear 261 B located at a second end of the leadscrew 260.
• a nut 270 integral with or attached to a pin 290 is meshed with the thread of the leadscrew 260 and operates as described with respect to the first embodiment.
• the leadscrew 260 will not rotate and therefore the pin 290 will not move, thereby preventing rotation of the output shaft 250 due to the abutment of the stationary pin 290 with the sidewall of the channel.
• An optional bridge member is provided between the first and second extension arms 230A, 230B.
• the bridge member is a flexible bridge member 238 which is expandable and retractable.
• the flexible bridge member 238 could be a telescopic member or could be elastic.
• Such a bridge member 238 permits movement of the arms 230A, 230B in the same direction as each another, and permits movement of the arms 230A, 230B in the opposite direction to each other. However, when the arms 230A, 230B are moving in the opposite direction to each other, the bridge member will act to limit the extent of their movement.
• the bridge member could instead be a rigid bridge member which would help strengthen the structural rigidity of the arms 230A, 230B when they are moving in the same linear direction, and which would prevent the arms 230A, 230B from moving in opposite directions to one another.
• Figure 7 shows a side view of a fourth embodiment of a system having a rotary output.
• the guideway is a channel 455 extending through the output shaft 450.
• the pin 490 projects completely through the channel 455 in the output shaft 450, and is attached to or integral with a first nut 470A at its first end 491 A, and attached to or integral with a second nut 470B at its second end 491 B.
• Each nut 470A, 470B is meshed with its own respective leadscrew 460A, 460B.
• Each end of the pin 491 A, 491 B is coupled to the drive shaft 410 by a different arrestor path.
• the first end of the pin 491 A is coupled to the drive shaft 410 via the first arrestor path
• the second end of the pin 491 B is coupled to the drive shaft 410 via the second arrestor path, such that rotation of the drive shaft 410 results in movement of each end of the pin 490.
• both arrestor paths must be synchronised with the rotation of the output shaft 455 in order for the system to provide an output.
• the inputs of both arrestor paths are directly coupled to the drive shaft 410 via respective toothed sections 416A, 416B with the arrestor path functioning generally as described with respect to the first embodiment.
• one or both of the arrestor paths may instead receive an input from another component within the system such that the arrestor path is indirectly coupled to the drive shaft 410.
• the system could be configured such that the second arrestor path receives an input from a component within the transmission means 440, for example a rotating gear.
• FIG. 8 shows a fifth embodiment of a system.
• there is an arrestor path having an extension arm 330.
• the extension arm 330 is meshed to a drive shaft in a manner similar to that which has been described with regards to the previous embodiments.
• the extension arm 330 is meshed, via a toothed rack 368 and a series of gears 361 , 362, 363, 364 to a leadscrew 360.
• a nut 370 is meshed to the thread of the leadscrew 360.
• the nut 370 is attached to or integral with a toothed member 373, which is meshed with a gear 377.
• the gear 377 is attached to or integral with a first disc 352, having a first pin 390A and a second channel 355A.
• the first pin 390A projects into a first channel 355B on a second disc 354.
• the second disc 354 lies on a plane generally parallel to the first disc and includes a second pin 390B which projects into the second channel 355A of the first disc 352.
• Figure 9 shows a plan view of the system of Figure 8. As can be seen from figure 9, the second disc 354 is coupled to the output shaft 350 such that when the output shaft 350 rotates, the second disc 354 rotates.
• the second disc 354 may also be integral with the output shaft 350.
• a transmission path couples the drive shaft 310 to the output shaft 350 via transmission means 340 such that rotation of the drive shaft 310 results in rotation of the output shaft 350.
• the rotational movement of the discs 352, 354 will be synchronised with respect to one another such that the first and second pins 390A, 390B move along the respective channels 355B, 355A. If the rotations of the discs 352, 354 is not synchronised, then the first and second pins 390A, 390B will abut against the sidewalls of their respective channels 355B, 355A jamming the discs 352, 354 and thereby limiting the further rotation of the discs 352,354 and hence the further rotation of the output shaft 350.
• the discs 352, 354 In addition to being synchronised, for the system shown in figures 8 and 9 to provide an expected rotary output, the discs 352, 354 must rotate in opposite directions to each other. This does not limit each disc 352, 354 to only one direction of rotation, but rather requires that when one disc is rotating in one direction, the other disc will be rotating in the opposite direction. For example, where the first disc rotates in a clockwise direction, the second disc will rotate in an anti-clockwise direction, and vice versa.
• the geometry of the channels 355A, 355B will result in the first and second pins 390A, 390B abutting against the sidewalls of their respective channel 355B, 355A and hence inhibiting rotation of the discs 352, 354.
• the extension arm 330 is coupled to the first disc 352 via the leadscrew 360, and a series of gears.
• the particular arrangement chosen will depend on the extent to which the motion of the extension arm 330 needs be converted into rotational motion in the first disc 352 in order for rotation of the first disc 352 to be synchronised with rotation of the second disc 354 and/or the relative position of the drive shaft 310 with respect to the first disc.
• a single gear located at one end of the leadscrew 360 can suitably couple the extension arm 330 and the leadscrew 360.
• first and second disks need not be circular, but could be any other desired shape.
• Figure 10 shows a plan view of a sixth embodiment of a system having a rotary output.
• a transmission path comprising a transmission means 540 coupling the drive shaft 510 to the output shaft 550 such that rotation of the drive shaft 510 results in rotation of the output shaft 550.
• the system includes two arrestor paths, only one of which is shown in its entirety in Figure 10.
• first arrestor path as shown in Figure 10
• rotation of the drive shaft 510 results in rotation of intermediate shafts 531 , 532 coupled via bevelled gears which in turn result in rotation of first ring gear 561A.
• the output shaft 550 passes through the first ring gear 561 A without directly coupling their rotations.
• the first ring gear 561A is partially meshed with a first upper gear 567A and a first lower gear 567B.
• Figure 11 shows an end view of the first ring gear 561A and the first upper and lower gears 567A, 567B.
• the first upper and lower gears 567A, 567B are coupled to first endpoints of respective upper 560A and lower 560B leadscrews.
• the threads of the upper and lower leadscrews 560A, 560B are meshed with respective upper and lower nuts 570A, 560B.
• an elongated span member 575 couples the first nut 570A to the second nut 570B.
• a pin 590 is attached to or integral with the span member 575 and projects into a channel 555 in the output shaft 550. Therefore, when the toothed sections 585 are meshed with the first upper and lower gears 567A 1 567B, rotation of the first ring gear 561 A will result in rotation of the leadscrews 560A, 560B and hence linear movement of the pin 590.
• the first ring gear 561 A is partially meshed with the upper and lower gears 567A, 567B via first and second toothed sections 585.
• the toothed sections 585 are located on radially opposite portions of the first ring gear's 561A outer surface and each occupy around a quarter of the first ring gear's 561A circumference. Therefore, when the first ring gear 561A is rotating continuously, the toothed sections 585 will alternately mesh with the first upper and lower gears 567A, 567B for approximately 90 degrees of rotation at a time.
• the first arrestor path is calibrated such that the toothed sections 585 engage with the first upper and lower gears 567A, 567B when the nuts 570A, 570B are located at one end of their respective leadscrew 560A, 560B and disengage with the first upper and lower gears 567A, 567B when the nuts 570A, 57B reach the other end of their respective leadscrew 560A, 560B.
• the second arrestor path includes an extension arm 530 which is coupled to the drive shaft 510 such that rotation of the drive shaft 510 results in linear movement of the extension arm 530.
• the extension arm 530 is meshed to a second ring gear 561 B such that the linear movement of the extension arm 530 results in rotation of the second ring gear 561 B.
• the second ring gear 561 B is partially meshed with second upper and lower gears 568A, 568B via first and second toothed sections of the second ring gear 561 B.
• the toothed sections of the second ring gear 561 B are generally the same as those on the first ring gear 561A, but are angularly offset to correspond to the gaps between the toothed sections 585 of the first ring gear 561 A.
• the toothed sections of the second ring gear 561 B engage with respective second upper and lower gears 568A, 568B when the nuts 570A, 570B are located at one end of their respective leadscrew 560A, 560B and disengage with the first upper and lower gears 567A, 567B when the nuts 570A, 57B reach the other end of their respective leadscrew 560A, 560B.
• the first and second arrestor paths are arranged such that when the first ring gear 561 A is engaged with the first upper and/or lower gears 567A, 567B, the second ring gear is not engaged with the second upper and/or lower ring gears 568A, 568B, but when the second ring gear 561 B is engaged with the second upper and/or lower gears 568A, 568B, the first ring gear 561A is not engaged with the first upper and/or lower ring gears 567A, 567B
• the first and second arrestor paths are arranged such that the first ring gear 561A causes linear movement of the pin 590 in a first direction whilst the second ring gear 561 B causes linear movement of the pin 590 in a second direction which is opposite to the first direction.
• the first ring gear 561A can rotate in the opposite direction to that of the second ring gear 561 B.
• the leadscrews 560A, 560B will rotate and hence cause linear movement of the pin 590 in the first direction.
• the first ring gear 561A when coupled to the pin 590, will cause linear movement of the pin in a first direction and the second ring gear 561 B, when coupled to the pin 590, will cause linear movement of the pin in a second direction which is opposite to the first direction. Since only one of the first and second ring gears 561 A, 561 B can be coupled to the pin 590 at any one point in these formats and since the first and second ring gears 561 A, 561 B will couple to the pin 590 in alternating periods, continuous rotation of the first and second ring gears 561 A, 561 B results in the pin moving back and forth along its linear pin path.
• the linear motion of the pin 590 will be synchronised with the rotational output of the shaft 550. That is, the linear movement of the pin 590 will be synchronised with the rotational movement of the shaft 550 such that the portion of the channel 555 aligned with the pin's path corresponds with the position of the pin, for any given rotation of the drive shaft 510. Since both arrestor paths drive the linear motion of the pin 590, both arrestor paths will be synchronised with respect to the rotation of the output shaft and hence each other.
• the movement of the pin 590 back and forth along its linear path is dependent upon the arrestor paths being configured such that when one of the ring gears 561 A, 561 B is engaged with the leadscrews 560A, 560B and causing movement of the pin 590, the other ring gear is not engaged with the leadscrews 560A, 560B and hence is not causing movement of the pin 590 in these formats.
• the arrestor path may begin to cause its ring gear engage with the respective upper and lower gears and therefore leadscrews 560A, 560B at points in which the other ring gear is engaged with the respective upper and lower gears and leadscrews 560A, 560B.
• the first ring gear 561 A could engage with the leadscrews 560A, 560B whilst the second ring gear 561 B is engaged with the leadscrews 560A, 560B. Since the ring gears are rotating in different directions, each ring gear would be applying opposing rotational forces to the ends of the leadscrews 560A, 560B. Therefore, the leadscrews 560A, 560B would jam and hence the pin 590 would no longer move along its linear path, thereby preventing any further rotation of the output shaft 550.
• the output shaft 550 would no longer rotate as expected. In such a case, synchronisation between the rotation of the output shaft 550 and the linear movement of the pin 590 would be lost. If the motions of the pin 590 and the output shaft 550 are out of sync, the portion of the guideway aligned with the path will not correspond with the position of the pin such that the pin will abut against a sidewall of the guideway and limit the further rotation of the output shaft. When the system is providing an expected rotary output, the pin 590 will move back and forth along the channel and the output shaft 550 will rotate.
• the output shaft rotates continuously and therefore the channel is provided with an appropriate profile such that the output shaft 550 will rotate and the pin 590 will move back and forth along the channel without the pin abutting against a sidewall of the channel 555.
• the channel 555 could be a continuous channel such that its endpoints connect to form a continuous loop arrangement.
• Figure 10 shows two leadscrews each driving a nut with a span member between supporting the pin (in a similar manner as shown in Figure 5), it will be appreciated that a single leadscrew could be used with a single nut and associated pin (in a similar manner to that shown in Figures 1 to 3).
• the ring gears could include fewer or more toothed sections provided the toothed sections on the two ring gears are offset from each other, and, where two or more leadscrews are provided that these are each driven synchronously.
• Figure 10 shows two arrestor paths, namely a first arrestor path on the left hand-side of the figure driving the first ring gear 561A and a second arrestor path on the right hand-side of the figure driving the second ring gear 561 B.
• the left hand-side of the figure could instead include one or more arrestor paths to drive the first ring gear 561 A.
• the right hand-side of the Figure could include one or more arrestor paths to drive the second ring gear 561 B.
• the arrestor paths on either side of the Figure could include any appropriate arrangement of gears, bevelled gears or any other suitable components such that rotation of the drive shaft 510 results in movement of the pin
• Figure 12 shows a plan view of a seventh embodiment of a system having a rotary output.
• the drive shaft 614 and the output shaft 650 are located such that their longitudinal axes are perpendicular with respect to one another. It will therefore be appreciated that the present invention embodies rotating systems in which the drive shaft and the output shaft have different orientations with respect to one another.
• Figure 12 shows one way in which the transmission path can couple the drive shaft 614 to the output shaft 650 such that rotation of the drive shaft 10 results in rotation of the output shaft 50.
• the drive shaft 610 is a leadscrew.
• the thread of the drive shaft 610 is meshed with a nut 620.
• the nut 620 is attached to or integral with an extension arm 630 such that rotation of the drive shaft 610 results in movement of the extension arm 630.
• One end of the extension arm 630 meshes directly with at least one gear located at one end of a leadscrew 660. Therefore, rotation of the drive shaft 610 result in rotation of the leadscrew 660, via the linear movement of the extension arm 630.
• a nut 670 is attached to or integral with a pin 690.
• the nut 670 is meshed with the thread of the leadscrew 660 such that rotation of the leadscrew 660 results in linear movement of the nut 670 and the pin 690. Therefore, rotation of the drive shaft 610 results in proportional linear movement of the pin 690 via the extension arm 630 and the leadscrew 660.
• the pin 690 projects into a channel 655 in a rotatable shaft 658.
• the rotatable shaft 658 is coupled to the output shaft 650 via a connecting means 651 , such that rotation of the output shaft 650 results in rotation of the rotatable shaft 658, and hence rotation of the channel 655.
• the transmission path includes a transmission arm 645 which is attached to or integral with the extension arm 630. Therefore, as with the extension arm 630, rotation of the drive shaft 610 results in linear movement of the transmission arm 645.
• One end of the transmission arm 645 meshes with at least one of the gears 642.
• the gear 642 is attached to or integral with the output shaft 650 such that linear movement of the transmission arm 645 results in rotation of the output shaft 650. Since the output shaft 650 is coupled to the rotatable shaft 658, rotation of the output shaft 650 results rotation of the rotatable shaft 658. Therefore, when the drive shaft 610 is driven such that it rotates, rotation of the drive shaft 610 will result in a proportional linear movement of the pin 690 and proportional rotation of the rotatable shaft 658 and channel 655.
• the pin 690 moves along the channel 655 and the output shaft 650 and the rotatable shaft 658 rotate. That is, the linear movement of the pin 690 is synchronised with the rotation of the output shaft 650 such that as the output shaft 650 rotates, at least a portion of the channel 655 corresponds with the position of the pin 690 for any linear movement of the pin 690 and/or rotation of the output/rotatable shaft 650/658.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Transmission Devices (AREA)
• Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
• Pivots And Pivotal Connections (AREA)
• Manipulator (AREA)

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• 2010
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