AU2013249210B2

AU2013249210B2 - Torque sensing pulleys and related methods and systems

Info

Publication number: AU2013249210B2
Application number: AU2013249210A
Authority: AU
Inventors: Richard Brad Ellis; Joshua Sean KAPP; Trenton Von LARSEN
Original assignee: Ifit Inc
Current assignee: Ifit Inc
Priority date: 2012-04-19
Filing date: 2013-04-18
Publication date: 2016-06-09
Anticipated expiration: 2033-04-18
Also published as: WO2013158887A1; AU2013249210A1; EP2838624A4; CN104245057A; CN104245057B; EP2838624A1

Abstract

An exercise machine includes a frame, a pulley, a first sensor, and a second sensor. The pulley includes an inner hub, an outer hub, and at least one biasing element. The inner hub further includes at least one position indicator. Additionally, the outer hub includes at least one position indicator and may be rotatable relative to the inner hub. The at least one biasing element may bias the outer hub to a first angular position relative to the inner hub. The first sensor may be fixed relative to the frame and positioned to detect the at least one position indicator of the inner hub. The second sensor may also be fixed relative to the frame and positioned to detect the at least one position indicator of the outer hub.

Description

TITLE

TORQUE SENSING PULLEYS AND RELATED METHODS AND SYSTEMS TECHNICAL FIELD

[0001] In general, the present disclosure relates to pulleys for determining a torque. More specifically, the present disclosure relates to torque sensing pulleys for exercise devices and related methods.

BACKGROUND

[0002] Stationary exercise equipment may be configured to approximate various devices utilized in competitive sports. For example, a stationary bicycle may approximate the pedaling and operation of a road bicycle and a stationary rowing machine may approximate the rowing and operation of a sculling boat. Accordingly, athletes may utilize such exercise equipment to train for competitions, such as bicycle racing or sculling.

[0003] Stationary exercise equipment may provide several advantages to athletes. Stationary exercise devices may facilitate indoor training, so that athletes can train in a temperature controlled environment. Additionally, stationary exercise devices may facilitate monitoring of the athlete's performance, such as speed, heart rate, average power output, etc.

[0004] For certain sports, such as cycling, it may be desirable to determine the instantaneous torque that an athlete transfers to the equipment (e.g., the torque applied to a crank set of a bicycle through the foot pedals and crank arms). Torque measurements have traditionally been acquired from bicycle crank sets by systems utilizing strain gauges. Such systems, however, are relatively complex and expensive.

[0005] One type of torque measuring device is disclosed in U.S. Pat. No. 7,806,006 issued to Robert Ryan Phillips et al. and assigned to Grand Valley State University. In this patent, a plurality of strain gauges are mounted on each crank arm of the bicycle to provide a measure of the torque applied to each crank arm. Each strain gauge includes a self-contained power, electrical circuitry, and a wireless transmitter for transmitting the strain measurement information to a main controller.

DISCLOSURE OF THE INVENTION

[0006] In one aspect of the disclosure, a pulley is configured or use with an exercise machine.

[0007] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include an inner hub comprising at least one position indicator.

[000S] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include an outer hub comprising at least one position indicator.

[0009] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include the outer hub being rotatable relative to the inner hub.

[0010] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include at least one biasing element biasing the outer hub to a first angular position relative to the inner hub.

[0011] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include a dampener positioned to dampen oscillatory motion of the outer hub relative to the inner hub.

[0012] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include damping grease positioned at an interface between the inner hub and the outer hub.

[0013] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include damping grease having a viscosity greater than 100 Pa satSTP.

[0014] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include damping grease formed at least in part of silica.

[0015] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include a circumferentially extending surface configured to interface with a belt.

[0016] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include crank arms with foot pedals coupled to the inner hub.

[0017] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include at least one position indicator of an outer hub having a plurality of circumferentially spaced position indicators.

[0018] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include each position indicator of the outer hub being positioned at substantially the same radial distance from a center of the outer hub.

[0019] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include at least one position indicator of the inner hub having a plurality of circumferentially spaced position indicators.

[0020] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include each position indicator of the inner hub being positioned at substantially the same radial distance from a center of the inner hub.

[0021] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include at least one position indicator of the inner hub having at least one magnet.

[0022] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include at least one position indicator of the outer hub having at least one magnet.

[0023] In one aspect of the disclosure, a method of measuring a torque applied to a pulley may include providing a pulley.

[0024] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include providing the pulley may comprise providing a pulley comprising an inner hub comprising at least one position indicator.

[0025] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include providing the pulley may comprise providing a pulley comprising an outer hub comprising at least one position indicator, the outer hub rotatable relative to the inner hub.

[0026] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include providing a pulley including at least one biasing element biasing the outer hub to a first angular position relative to the inner hub.

[0027] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include detecting the at least one position indicator of the inner hub as it rotates past a first sensor.

[0028] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include detecting the at least one position indicator of the outer hub as it rotates past a second sensor.

[0029] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include determining a first time interval correlating to a difference in time of a signal form the first sensor and a signal from the second sensor.

[0030] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include evaluating the first time interval relative to a rotational speed of the pulley to determine a torque applied to the pulley.

[0031] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include determining a second time interval correlating to a difference in time of a signal from one of the first sensor and the second sensor and a subsequent signal from that same sensor.

[0032] Another aspect of the disclosure may include any combination of the above-mentioned features and may further include evaluating the first time interval relative to the rotational speed of the pulley to determine the torque applied to the pulley including evaluating a ratio of the first time interval and the second time interval to determine the torque applied to the pulley.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings illustrate various embodiments of the present methods and systems and are a part of the specification. The illustrated embodiments are merely examples of the present systems and methods and do not limit the scope thereof.

[0034] FIG. 1 is an isometric view of a stationary bicycle according to an embodiment of the present disclosure.

[0035] FIG. 2 is a cross-sectional view of a pulley and a portion of a frame of the stationary bicycle of FIG. 1.

[0036] FIG. 3 is an isometric view of the outer hub of the pulley of FIG. 2.

[0037] FIG. 4 is an isometric view of a hub plate of an inner hub of the pulley of FIG. 2.

[0038] FIG. 5 is an isometric view of a retaining plate of the inner hub of the pulley of FIG. 2.

[0039] FIG. 6 is an isometric view of a connecting plate of the inner hub of the pulley of FIG. 2.

[0040] FIG. 7 is an isometric view of a center plate and shaft assembly of the inner hub of the pulley of FIG. 2.

[0041] FIG. 8 is an isometric view of a first side of the pulley of FIG. 2.

[0042] FIG. 9 is an isometric view of a second side of the pulley of FIG. 2.

[0043] FIG. 10 is a schematic diagram of electronic components of the stationary bicycle of FIG. 1.

[0044] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

[0045] Fig. 1 is an exercise machine, specifically a stationary bicycle 10, according to an embodiment of the present disclosure. The stationary bicycle 10 includes a frame 12, a seat 14, handles 16, a console 18, and crank arms 20 and foot pedals 22 coupled to a drive mechanism 24. The drive mechanism 24 may include a pulley 26 coupled to the bicycle crank arms 20, a resistance device 28, and a drive element, such as a belt 30, extending between the resistance device 28 and the pulley 26.

[0046] As shown in FIG. 2, the pulley 26 may include an inner hub 32, an outer hub 34, and at least one biasing element, such as springs 36 (see FIG. 9). The inner hub 32 may be located at the center of the pulley 26 and may be coupled to the crank arms 20. The inner hub 32 may include two or more plates, such as a hub plate 38, a retaining plate 40, a connecting plate 42, and a center plate 44. The plates 38, 40, 42, 44 may be joined together, such as by one or more of rivets, bolts 46 (see FIG. 9), screws 48, adhesive, and other fastening elements.

[0047] In a radially outer region, the plates 38, 40 may define a channel 50 that extends circumferentially around the inner hub 32. The inner hub 32 may additionally include at least one position indicator 52 located thereon. For example, position indicators 52 may include a plurality of magnets circumferentially spaced around the inner hub 32. Each position indicator 52 may be positioned at substantially the same radial distance from an axis of rotation 54 of the pulley 26, and may be spaced apart from each other by a predetermined angular distance. In one embodiment, as shown in FIGS. 5 and 8, four position indicators 52 may be positioned at 90 degree increments relative to one another.

[0048] A portion of the outer hub 34 may be positioned within the channel 50 defined by the inner hub 32. A radially inner cylindrical surface of the outer hub 34 may be positioned adjacent a corresponding cylindrical surface of the inner hub 32 and may be sized and configured to rotate about the cylindrical surface of the inner hub 32. The outer hub 34 may be rotatable relative to the inner hub 32 over an angular distance a (see FIG. 9). The springs 36, or other biasing elements, may bias the outer hub 34 to a first angular position relative to the inner hub 32.

[0049] An isometric view showing a first side of the outer hub 34 is shown in FIG. 3. The body of the outer hub 34 may be formed of injection molded polymer. For example, the outer hub 34 may be formed from a structurally reinforced polymer, such as glass-filled nylon. This may facilitate the manufacture of a relatively complex shaped outer hub 34 at a relatively low cost.

[0050] The outer hub 34 may include a radially outer surface 56 shaped and configured to receive a belt thereon. For example, the radially outer surface 56 may include a plurality of circumferentially extending grooves sized and positioned to correspond to grooves of a grooved belt.

[0051] A radially inner surface 58 of the outer hub 34 may have a generally cylindrical shape. The first side of the outer hub may include one or more lugs 60 and one or more biasing member retaining features 62 (e.g., spring retainers). An opposing, second side (see FIG. 8) may include one or more position indicators 64. For example, the second side may include four cavities spaced circumferentially at a first radial distance from the center of the inner hub and a magnet (e.g., a ceramic magnet) may be positioned within each cavity, respectively.

[0052] The inner hub 32 may comprise a plurality of components, including the hub plate 38, the retaining plate 40, the connecting plate 42, and the center plate 44, which may be incorporated into an assembly including a shaft 66.

[0053] An isometric view of the hub plate 38 of the inner hub 32 is shown in FIG. 4. The body of the hub plate 38 may be formed of injection molded polymer, similar to the body of the outer hub 34. For example, the hub plate 38 may be formed from a structurally reinforced polymer, such as glass-filled nylon. The hub plate 38 may include one or more channels 68 formed therein and one or more biasing member retaining features 70 (e.g., spring retainers). The hub plate 38 may also include a cylindrical bearing surface 72, and a plurality of circumferentially spaced apertures 74.

[0054] An isometric view of the retaining plate 40 of the inner hub 32 is shown in FIG. 5. As shown, the retaining plate 40 may include a plurality of apertures 75 and the position indicators 52. For example the retaining plate 40 may include four cavities spaced circumferentially at a first radial distance from the center and a magnet (e.g., a ceramic magnet) may be positioned within each cavity, respectively, to provide the position indicators 52.

[0055] As can be seen in the cross-section illustrated as FIG. 2, the hub plate 38 and retaining plate 40 together may form the channel 50 of the inner hub 32, wherein the outer hub 34 is positioned. Additionally, a damping grease 76 may be positioned at the interface between the outer hub 34 and the inner hub assembly 32. The damping grease 76 may be a grease having a relatively high viscosity, which provides damping of oscillatory motion of the outer hub 34 relative to the inner hub assembly 32. For example, the damping grease 76 may have a dynamic viscosity greater than 100 pascal seconds (Pa-s) at standard temperature and pressure (STP) (i.e., greater than one kilopoise at STP). In some embodiments, the damping grease 76 may comprise a synthetic hydrocarbon fluid base and a silica thickener and may have a dynamic viscosity of about 220 Pa-s at STP (i.e., about 2.2 kilopoise at STP). For example, damping grease sold under the tradename ROCOL ® KILOPOISE 0868S, available from ROCOL of Leeds, England, may be a suitable damping grease 76.

[0056] An isometric view of the connecting plate 42 of the inner hub 32 is shown in LIG. 6. As shown, the connecting plate 42 may be configured as an annular body including a plurality of outer apertures 78 and a plurality of inner apertures 80 formed therein.

[0057] An isometric view of an assembly 82 including the center plate 44 and the shaft 66 is shown in LIG. 7. As shown, the shaft 66 may have a first end 84 and an opposing second end 86 (see LIG. 9), each configured for attachment to a respective crank arm 20 (see LIG. 1). A portion of the shaft 66 positioned between the first end 84 and the second end 86 may be sized and configured to couple with at least one bearing 88 for rotatable attachment to the frame via a bearing block 90 (see FIG. 1).

[0058] The shaft 66 may be fixed to the center plate 44. For example, the shaft 66 and the center plate 44 may be a unitary structure, machined from a monolithic material. In another example, the shaft 66 and center plate 44 may be formed separately and then joined together, such as by a weld joint, fastener, adhesives, and the like. The center plate 44 and shaft 66 may be comprised of a metal, such as a steel, or any other material configured to provide sufficient structural strength to receive forces imparted on the foot pedals 22 and crank arms 20 by a user and to support the pulley 26 relative to the frame 12.

[0059] To assemble the pulley 26, the damping grease 76 may be applied to the outer hub 34, the hub plate 38, and/or, the retaining plate 40. Then, the lugs 60 of the outer hub 34 may be aligned with the corresponding channels 68 of the hub plate 38. Additionally, the biasing member retaining features 62 of the outer hub 34 may be aligned with the corresponding biasing member retaining features 70 of the hub plate 38. The radially inner surface 58 of the outer hub 34 may then be positioned on the cylindrical bearing surface 72 of the hub plate 38.

[0060] After the outer hub 34 and hub plate 38 have been nested together, the plurality of outer apertures 78 of the connecting plate 42 may be aligned with the corresponding apertures 74 of the hub plate 38 and apertures 75 of the retaining plate 75. The screws 48 may then be inserted to fasten the connecting plate 42, the hub plate 38, and the retaining plate 40 together.

[0061] After the connecting plate 42, the hub plate 38, and the retaining plate 40 have been fastened together via the screws 48, at least one biasing member may be positioned between the hub plate 38 and the outer hub 34. For example, the springs 36 may each be compressed and inserted between corresponding sets of biasing member retaining features 62, 70 of the hub plate 38 and the outer hub 34. After the springs 36 are positioned between the biasing member retaining features 62, 70 of the hub plate 38 and the outer hub 34, a first side of each lug 60 of the outer hub 34 may be biased into contact with a first side of each respective channel 68 of the hub plate 38, as shown in FIG. 9.

[0062] Meanwhile, the shaft 66 may be positioned within the bearing block 90 and bearings 88, which may be one or more of ball bearings, roller bearings, cone bearings and plain bearings. The bearings 88 may facilitate the rotation of the shaft relative to the bearing block 90 of the frame 12.

[0063] After the shaft 66 and the center plate 44 have been installed onto the bearing block 90 of the frame 12, the center plate 44 and connecting plate 42 may be joined together to complete the pulley 26. The center plate 44 may include a plurality of apertures 92 sized and positioned to align with the plurality of inner apertures 80 of the connecting plate 42. After the apertures 92 of the center plate 44 have been aligned with the inner apertures 80 of the connecting plate 42, the bolts 46 may be inserted therein to fasten the connecting plate 42 and the center plate 44 together.

[0064] When the pulley 26 has been fully assembled onto the exercise device (e.g., the stationary bicycle 10), the belt 30 may be positioned over the radially outer surface 56 of the outer hub 34. The belt 30 may also be positioned over a pulley of the resistance device 28, which may provide a selectable mechanical resistance to the movement of the belt 30. Additionally, sensors 94, 96 may be positioned near the pulley 26 and fixed relative to the frame 12 of the exercise device 10, as shown in FIG. 2. The sensors 94, 96 (e.g., hall effect sensors) may be positioned at location corresponding to the radial locations of the position indicators 52, 64 of the pulley 26.

[0065] A first sensor 94 may be positioned to detect the position indicators 52 of the inner hub 32. The first sensor 94 may be positioned such that, as the pulley 26 is rotated, the position indicators 52 of the inner hub 32 (e.g., the position indicators 52 located on the retaining plate 40) may pass proximate to the first sensor 94.

[0066] Likewise, a second sensor 96 may be positioned to detect the position indicators 64 of the outer hub 34. The second sensor 96 may be positioned such that, as the pulley 26 is rotated, the position indicators 64 of the outer hub 34 may pass proximate to the second sensor 96.

[0067] When no torque is applied to the pulley 26, the springs 36 may bias the position indicators 52 of the inner hub 32 to a first position relative to the position indicators 64 of the outer hub 34. For example, the position indicators 52 of the inner hub 32 may be each be angularly aligned with a respective position indicator 64 of the outer hub 34.

[0068] During operation, torque may be applied to the pulley 26, such as by a user applying a torque via the foot pedals 22 and crank arms 20 attached to the pulley 26. The applied torque may overcome the biasing force of the springs 36, and the inner hub 32 may rotate relative to the outer hub 34. The rotation of the inner hub 32 relative to the outer hub 34 may cause the position indicators 52 of the inner hub 32 to be moved to a different angular position relative to the position indicators 64 of the outer hub 34.

[0069] As the pulley 26 rotates, the position indicators 52 of the inner hub 32 may rotate past the first sensor 94 and the first sensor 94 may generate a signal indicating the time that each position indicator 52 of the inner hub 32 passes. Additionally, the position indicators 64 of the outer hub 34 may rotate past the second sensor 96 and the second sensor 96 may generate a signal indicating the time that each position indicator 64 of the outer hub 34 passes.

[0070] The signals from the first and second sensors 94, 96 may be delivered to a central processing unit (CPU) of a computer 98, which may analyze the signals. The rotational speed (e.g., the number or rotations per minute (RPM)) of the pulley 26 may be analyzed by looking at signals from the first or second sensor 94, 96, individually. Utilizing the known distance between each position indicator 64 of the outer pulley, the rotational speed may be calculated with the difference in time between sensing each position indicator 64 with the second sensor 96. For embodiments wherein the outer hub 34 comprises four equally spaced position indicators 64, the rotational speed may be calculated by the equation R=1/(4(T02-T0i)). Wherein: R is the rotational speed; TOi is a time a first position indicator 64 of the outer hub 34 passes the second sensor 96; and TO2 is a time a next position indicator 64 of the outer hub 34 passes the second sensor 96.

[0071] In further embodiments, data sensed by the first sensor 94 may be utilized to determine the rotational speed. Additionally, multiple data points may be averaged to determine a rotational speed.

[0072] Utilizing a calculated rotational speed of the pulley 26, the difference in time between signals from the first and second sensors 94, 96 may be utilized to determine the amount of rotational displacement of the inner hub 32 relative to the outer hub 34, which displacement occurs as a result of an applied torque. When the pulley 26 is rotating without an applied torque, a difference in time between the sensing of a position indicator 52 of the inner hub 32 by the first sensor 94 and the sensing of a corresponding position indicator 64 of the outer hub 34 by the second sensor 96 may be calculated by the equation ΔΤ0 = (TO0 -TI0). Wherein: ΔΤ0 is a difference in time between signals from the first and second sensors 94, 96 when no torque is applied to the pulley 26; TOo is a time a position indicator 64 of the outer hub 34 passes the second sensor 96; and TIo is a time a corresponding position indicator 52 of the inner hub 32 passes the first sensor 94.

[0073] When the pulley 26 is rotating with a torque applied, a difference in time between the sensing of a position indicator 52 of the inner hub 32 by the first sensor 94 and the sensing of a corresponding position indicator 64 of the outer hub 34 by the second sensor 96 may be calculated by the equation ΔΤι = (TOi -TIi).Wherein: ΔΤι is a difference in time between signals from the first and second sensors 94, 96 when torque is applied to the pulley 26; TOi is a time a position indicator 64 of the outer hub 34 passes the second sensor 96; and TIi is a time a corresponding position indicator 52 of the inner hub 32 passes the first sensor 94.

[0074] Additionally, the angle of displacement, A, can be calculated with the equation A = R (ΔΤ i - ΔΤο). The value of ΔΤο will be a constant value, which will be based on the design of the pulley 26. In embodiments wherein corresponding position indicators 52, 64 of the inner and outer hub 32, 34 pass the first and second sensors 94, 96 substantially simultaneously, when no torque is applied to the pulley, the value of ΔΤ0 may equal zero and the equation for the angle of displacement may be simplified to A = R · ΔΤι.

[0075] With a known angle of displacement of the inner hub 32 relative to the outer hub 34, the applied torque may be calculated. In some embodiments, each biasing member may be a spring 36 and the applied torque may be calculated utilizing Hooke's law, F = k x, wherein: F is the applied force; k is the spring constant; and x is the displacement of the spring 36.

[0076] After determining the applied force F, the torque applied to the pulley 26 may be calculated by the equation T = F D, wherein: T is the torque applied to the pulley 26; F is the applied force; and D is the radial distance of each spring 36 from the axis of rotation 54 of the pulley 26.

[0077] In further embodiments, the applied torque may be calculated by utilizing empirical data (i.e., information obtained through observation or experimentation). For example, various torques may be applied to the pulley 26 and the displacement corresponding to each torque may be measured. Then, in use, the computer 98 may utilize a look-up table or a function representing the empirical data to determine the applied torque.

[0078] Upon determining an applied torque, the computer 98 may send a signal to the console 18 to provide torque output information to the user. The user may then utilize this information to achieve a desired workout, to work toward a higher peak torque output, and/or to work toward a sustained torque output.

INDUSTRIAL APPLICABILITY

[0079] Exercise machines, such as stationary bicycles, may include a pulley that may be utilized to determine the torque applied thereto, such as via foot pedals. Exercise machines including such pulleys may be utilized by athletes for training purposes. Accordingly, athletes may receive feedback from the exercise machine regarding torque input and improve their performance.

[0080] The pulley may comprise an inner hub, an outer hub, and at least one biasing element, such as springs. In some embodiments, the biasing elements may be helical compression springs. In further embodiments, the biasing elements may be an elastic material, tension springs, leaf springs, compliant mechanisms, or another biasing element.

[0081] The inner hub may located at the center of the pulley and may be coupled to the crank arms. The inner hub may comprise two or more plates that may be joined together, such as by one or more of rivets, bolts, screws, adhesive, and other fastening elements. In a radially outer region, the plates may define a channel that extends circumferentially around the inner hub. The inner hub may additionally include at least one position indicator located thereon. For example, position indicators may comprise a plurality of magnets circumferentially spaced around the inner hub. In some embodiments, the inner hub may include four position indicators. In further embodiments, the inner hub may include at least one position indicator, and any number of additional position indicators distributed around the inner hub, without limitation.

[0082] Each magnet may be positioned at substantially the same radial distance from an axis of rotation of the pulley, and may be spaced apart from each other by a predetermined angular distance. In one embodiment, four magnets may be positioned at 90 degree increments relative to one another. In further embodiments, a different number of magnets may be utilized, and any angular distance between position indicators may be utilized.

[0083] A portion of the outer hub may be positioned within the channel defined by the inner hub. A radially inner cylindrical surface of the outer hub may be positioned adjacent a corresponding cylindrical surface of the inner hub and may be sized and configured to rotate about the cylindrical surface of the inner hub. The outer hub may be rotatable relative to the inner hub over an angular distance u. The springs, or other biasing elements, may bias the outer hub to a first angular position relative to the inner hub.

[0084] The body of the outer hub may be comprised of injection molded polymer.

For example, the outer hub may be formed from a structurally reinforced polymer, such as glass-filled nylon. This may facilitate the manufacture of a relatively complex shaped outer hub body at a relatively low cost. In further embodiments, the outer hub may be formed from another material. For example, the outer hub may be formed from a metal, such as cast aluminum.

[0085] The outer hub may comprise a radially outer surface shaped and configured to receive a drive element, such as a belt thereon. For example, the radially outer surface may include a plurality of circumferentially extending grooves sized and positioned to correspond to grooves of a grooved belt. In further embodiments, the drive element may comprise a different type of belt, such as a v-belt. In yet further embodiments, the drive element may be a chain, a geared cog, a worm-drive, or another friction or engagement drive element.

[0086] A radially inner surface of the outer hub may have a generally cylindrical shape. A first side surface of the outer hub may include one or more lugs and one or more biasing member retaining features (e.g., coil spring retainers). An opposing, second side surface may include one or more position indicators. For example, the second side surface may include four cavities spaced circumferentially at a first radial distance from the center and a magnet (e.g., a ceramic magnet) may be positioned within each cavity, respectively.

[0087] The inner hub may comprise a plurality of components, including a hub plate, a retaining plate, a center plate and shaft assembly and a connecting plate.

[0088] The body of the hub plate of the inner hub may be comprised of injection molded polymer, similar to the body of the outer hub. For example, the hub plate may be formed from a structurally reinforced polymer, such as glass-filled nylon. The hub plate may include one or more channels formed therein and one or more biasing member retaining features (e.g., coil spring retainers). The hub plate may also include a cylindrical bearing surface, and a plurality of circumferentially spaced apertures. In further embodiments, the hub plate may be formed from another material. For example, the hub plate may be formed from a metal, such as cast aluminum.

[0089] The retaining plate may include one or more position indicators. For example the retaining plate may include four cavities spaced circumferentially at a first radial distance from the center and a magnet (e.g., a ceramic magnet) may be positioned within each cavity, respectively.

[0090] A damping grease may be positioned at the interface between the outer hub and the inner hub assembly. The damping grease may be a grease having a relatively high viscosity, which provides damping of oscillatory motion of the outer hub relative to the inner hub assembly. For example, a damping grease having a dynamic viscosity greater than 100 pascal seconds (Pa-s) at standard temperature and pressure (STP) (i.e., greater than one kilopoise at STP) may be utilized. In some embodiments, the damping grease may comprise a synthetic hydrocarbon fluid base and a silica thickener and may have a dynamic viscosity of about 220 Pa-s at STP (i.e., about 2.2 kilopoise at STP). For example, damping grease sold under the tradename ROCOL ® KILOPOISE 0868S, available from ROCOL of Leeds, England, may be a suitable damping grease.

[0091] The center plate and shaft assembly of the inner hub assembly may include a shaft having a first end and an opposing second end, each configured for attachment to a respective crank arm. A portion of the shaft positioned between the first end and the second end may be sized and configured to fit at least one bearing for rotatable attachment to the frame via a bearing block. The shaft may be coupled to the center plate. For example, the shaft and center plate may be a unitary structure, machined from a monolithic material. For another example, the shaft and center plate may be formed separately and then joined together, such as by a weld joint. The center plate and shaft assembly may be comprised of a metal, such as a steel, which may provide sufficient structural strength to receive forces imparted on the foot pedals and crank arms by a user and to support the pulley relative to the frame. Accordingly, the shaft may be positioned within a bearing block and bearings, such as one or more of ball bearings, roller bearings, cone bearings and plain bearings, may facilitate the rotation of the shaft relative to the bearing block of the frame.

[0092] Sensors may be positioned near the pulley and fixed relative to the frame of the exercise device. The sensors may be positioned at location corresponding to the radial locations of the position indicators of the pulley. In some embodiments, the sensors may be hall effect sensors. In further embodiments, the sensors may comprise other sensors capable of detecting a position indicator. For example, the sensors may comprise one or more of an infrared sensor, a laser, a photoelectric sensor, and an inductive sensor.

[0093] A first sensor may be positioned to detect the position indicators of the inner hub. The first sensor may be positioned such that, as the pulley is rotated, the position indicators of the inner hub (e.g., the position indicators located on the retaining plate) may pass proximate to the first sensor.

[0094] Likewise, a second sensor may be positioned to detect the position indicators of the outer hub. The second sensor may be positioned such that, as the pulley is rotated, the position indicators of the outer hub may pass proximate to the second sensor.

[0095] When no torque is applied to the pulley, the biasing members may position the position indicators of the inner hub to a first position relative to the position indicators of the outer hub. For example, the position indicators of the inner hub may be each be angularly aligned with a respective position indicator of the outer hub.

[0096] In operation, torque may be applied to the pulley, such as by a user applying a torque via the foot pedals and crank arms attached to the pulley. The applied torque may overcome the biasing force of the biasing members, and the inner hub may rotate relative to the outer hub. The rotation of the inner hub relative to the outer hub may cause the position indicators of the inner hub to be moved to a different angular position relative to the position indicators of the outer hub.

[0097] As the pulley rotates, the position indicators of the inner hub may rotate past the first sensor and the first sensor may generate a signal indicating the time that each position indicator of the inner hub passes. Additionally, the position indicators of the outer hub may rotate past the second sensor and the second sensor may generate a signal indicating the time that each position indicator of the outer hub passes.

[0098] The signals from the first and second sensors may be delivered to a central processing unit (CPU) of a computer, which may analyze the signals. The rotational speed (e.g., the number or rotations per minute (RPM)) of the pulley may be analyzed by looking at signals from the first or second sensor, individually. Utilizing the known distance between each position sensor of the outer pulley, the rotational speed may be calculated with the difference in time between sensing each position indicator.

[0099] Upon determining an applied torque, the computer may send a signal to a console to provide torque output information to the user. The user may then utilize this information to achieve a desired workout, to work toward a higher peak torque output, and/or to work toward a sustained torque output. In further embodiments, the signal may be recorded by the onboard computer, or an external computer, and the data may be analyzed to provide additional information about a workout.

[0100] In this specification, the terms “comprise”, “comprises”, “comprising” or similar terms are intended to mean a non-exclusive inclusion, such that a system, method or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed.

[0101] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

Claims

WHAT IS CLAIMED IS:

1. A pulley for an exercise machine, the pulley comprising: an inner hub including at least one position indicator; an outer hub including at least one position indicator, the outer hub rotatable relative to the inner hub; at least one biasing element biasing the outer hub to a first angular position relative to the inner hub; and a dampener positioned to dampen oscillatory motion of the outer hub relative to the inner hub.
2. The pulley of claim 1, wherein the dampener comprises damping grease positioned at an interface between the inner hub and the outer hub.
3. The pulley of claim 2, wherein the damping grease has a viscosity greater than 100 Pa· s at STP.
4. The pulley of claim 3, wherein the damping grease comprises silica.
5. The pulley of claim 1, wherein the outer hub comprises a circumferentially extending surface configured to interface with a belt.
6. The pulley of claim 1, further comprising crank arms with foot pedals coupled to the inner hub.
7. The pulley of claim 1, wherein the at least one position indicator of outer hub comprises a plurality of circumferentially spaced position indicators, each positioned at substantially the same radial distance from a center of the outer hub, and wherein the at least one position indicator of the inner hub comprises a plurality of circumferentially spaced position indicators, each positioned at substantially the same radial distance from a center of the inner hub.
8. The pulley of claim 1, wherein the at least one position indicator of the inner hub includes at least one magnet, and wherein the at least one position indicator of the outer hub includes at least one magnet.
9. An exercise machine comprising: a frame; a pulley, the pulley including: an inner hub including at least one position indicator; an outer hub including at least one position indicator, the outer hub rotatable relative to the inner hub; at least one biasing element biasing the outer hub to a first angular position relative to the inner hub; and a dampener positioned to dampen oscillatory motion of the outer hub relative to the inner hub; a first sensor fixed relative to the frame and positioned to detect the at least one position indicator of the inner hub; and a second sensor fixed relative to the frame and positioned to detect the at least one position indicator of the outer hub.
10. The exercise machine of claim 9, wherein the dampener comprises damping grease positioned at an interface between the inner hub and the outer hub.
11. The exercise machine of claim 10, wherein the damping grease has a viscosity greater than 100 Pa· s at STP.
12. The exercise machine of claim 11, wherein the damping grease comprises silica.
13. The exercise machine of claim 9, further comprising a resistance device and a belt, the belt coupling the resistance device and the outer hub of the pulley.
14. The exercise machine of claim 9, further comprising crank arms with foot pedals coupled to the inner hub.
15. The exercise machine of claim 9, wherein the at least one position indicator of outer hub comprises a plurality of circumferentially spaced position indicators, each positioned at substantially the same radial distance from a center of the outer hub, and wherein the at least one position indicator of inner hub includes a plurality of circumferentially spaced position indicators, each positioned at substantially the same radial distance from a center of the inner hub.
16. The exercise machine of claim 9, wherein the at least one position indicator of the inner hub includes at least one magnet, and wherein the at least one position indicator of the outer hub includes at least one magnet.
17. A method of measuring a torque applied to a pulley, the method comprising: providing a pulley including: an inner hub including at least one position indicator; an outer hub including at least one position indicator, the outer hub rotatable relative to the inner hub; at least one biasing element biasing the outer hub to a first angular position relative to the inner hub; a dampener positioned to dampen oscillatory motion of the outer hub relative to the inner hub; detecting the at least one position indicator of the inner hub as it rotates past a first sensor; detecting the at least one position indicator of the outer hub as it rotates past a second sensor; determining a first time interval correlating to a difference in time of a signal form the first sensor and a signal from the second sensor; evaluating the first time interval relative to a rotational speed of the pulley to determine a torque applied to the pulley.
18. The method of claim 17, further comprising: determining a second time interval correlating to a difference in time of a signal from one of the first sensor and the second sensor and a subsequent signal from that same sensor; wherein evaluating the first time interval relative to the rotational speed of the pulley to determine the torque applied to the pulley comprises evaluating a ratio of the first time interval and the second time interval to determine the torque applied to the pulley.