This invention relates to an exercise device, and more particularly to a magnetic resistance arrangement for an exercise device.
An exercise device, such as a stationary bicycle trainer, incorporates a resistance unit for applying resistance during operation of the device. The resistance unit typically includes a rotatable member, such as a shaft or roller, that rotates in response to work performed by the user. Resistance to rotation of the shaft or roller is accomplished several different ways, including wind resistance, fluid resistance, and resistance established by one or more magnetic members that interact with an electrically conductive member which rotates along with the shaft or roller, to establish eddy current resistance to rotation of the shaft or roller. Examples of magnetic resistance mechanisms are shown and described in Wei. et. al. U.S. Pat. No. 5,879,273 as well as copending U.S. patent application Ser. No. 10/054,781 filed Jan. 23, 2002, the disclosures of which are hereby incorporated by reference. The '781 patent application discloses a magnetic resistance arrangement in which one or more magnets are located adjacent a rotating electrically conductive member. The magnets are moved outwardly under the influence of centrifugal forces resulting from rotation of the rotatable member to which the magnets are mounted. Such outward movement of the magnets increases the distance of the magnets from the axis of rotation of the rotatable shaft or roller, to increase the resistance to rotation of the shaft or roller in proportion to increased speed of operation. The '273 patent discloses a system in which one or more magnets are mounted to a plate. The plate is interconnected with an adjustment mechanism by which the spacing between the magnets and the rotatable electrically conductive member can be adjusted, to vary the eddy current force that applies resistance during operation of the device.
It is an object of the present invention to provide an adjustable magnetic resistance arrangement for a resistance unit for use in an exercise device such as a bicycle trainer. It is a further object of the invention to provide such an adjustable magnetic resistance arrangement in which the resistance is adjusted by the user independent of the speed of operation of the device. It is a further object of the invention to provide such an adjustable magnetic resistance arrangement which involves a relatively small number of parts, to facilitate assembly and to provide a relatively low cost of manufacture. Yet another object of the invention is to provide such an adjustable magnetic resistance arrangement in which resistance is adjusted by varying the space between a magnetic member and a rotatable electrically conductive member interconnected with a rotatable shaft or roller forming a part of the exercise device.
In accordance with the present invention, a resistance unit, such as for use in an exercise device, includes a body or housing and a rotatable member, such as a shaft or roller, that is rotatably mounted to the body or housing. In one application, the exercise device may be in the form of a stationary bicycle trainer in which the driven wheel of a bicycle is engaged with the shaft or roller, to impart rotation to the shaft or roller.
An electrically conductive member, such as a plate, is interconnected with the rotatable member. In one embodiment, the rotatable member is interconnected with a flywheel that rotates along with the rotatable member, and the electrically conductive member is secured to the flywheel so as to rotate along with the rotatable member and the flywheel. A magnetic member is mounted to the housing, and interacts with the electrically conductive member to establish eddy current resistance to rotation of the electrically conductive member, which is transferred to the rotatable member through the flywheel.
An adjustment mechanism is interposed between the magnetic member and the body or housing, for adjusting the space between the magnetic member and the electrically conductive member to vary the strength of the eddy current resistance. In one embodiment, the magnetic member is received within a passage formed in the body or housing, and the adjustment mechanism is operable to vary the position of the magnetic member within the passage so as to move the magnetic member toward and away from the electrically conductive member. The body or housing may define a pair of oppositely facing surfaces between which the passage is located. The electrically conductive member is located adjacent one of the oppositely facing surfaces, and the adjustment mechanism includes an actuator that is located adjacent the other of the oppositely facing surfaces. The actuator is preferably rotatable, and the adjustment mechanism is configured so as to vary the position of the magnetic member in response to rotation of the actuator.
A vane arrangement may be interposed between the electrically conductive member and the flywheel, for providing air movement upon rotation of the rotatable member and the flywheel, to cool bearings that provide rotatable mounting of the rotatable member to the body or housing.
The invention contemplates a resistance unit as summarized above, as well as an improvement in a resistance unit and a method of adjusting the resistance of a resistance unit, substantially in accordance with the foregoing summary.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.
The drawings illustrate the best mode presently contemplated of carrying out the invention.
In the drawings:
Referring to
Frame 22 has a pair of generally forwardly extending legs 38 attached to opposite ends of a generally U-shaped support member 40. Legs 38 also preferably extend outwardly with respect to support member 40, to provide stability for bicycle training device 20. Legs 38 and support member 40 are formed of a generally rigid material, such as metal tubing, and may have a circular cross section. Each of legs 38 is connected to support member 40 by a brace 42 that is secured to support member 40. A bolt 44 extends through the leg 38 and brace 42, and a nut is engaged with the threads of bolt 44 such that leg 38 is pivotable about bolt 44 between an extended position as shown, and a folded position for storage. Opposite the brace 42, each leg 38 also includes a foot 46 formed of a resilient high friction material, such as rubber, that serves to prevent the leg 38 from slipping with respect to the surface 26 on which the frame 22 is positioned. The support member 40 also includes a pair of feet 48 attached to opposite ends of a horizontal cross member 50 secured to the lower end of support member 40 opposite legs 38. Cross member 50 provides stability to the rear of bicycle training device 20, and assists legs 38 in holding bicycle training device 20 stable and stationary on the support surface 26.
Bicycle training device 20 includes a releasable engagement mechanism located at the upper end of support member 40, which includes a stationary engagement section 52 mounted to one of the legs of support member 40, and a movable engagement member 54 interconnected with a manually operated lever 56, which is mounted to the other leg of support member 40. In a known manner, one end of the axle of hub 30 is engaged with stationary engagement member 52, and lever 56 is operated so as to move within an angled cam slot 58 formed in a cylinder within which engagement member 54 is received, so as to bring movable engagement member 54 into engagement with the opposite end of the axle of hub 30. In this manner, the rear of bicycle 24 is engaged with and supported by frame 22, such that the rear wheel 32 of bicycle 24 is located above the support surface 26 and can thus be rotated by operation of the pedals of bicycle 24.
A resistance unit 60 is movably mounted to frame 22 adjacent cross member 50. Resistance unit 60 includes a housing or body 62 that is pivotably attached to support member 40 between a pair of mounting members 64, in a known manner. Each mounting member 64 is fixed to support member 40, and functions to hold resistance unit 60 on support member 40. Each mounting member 64 includes an opening 66, and a pivot shaft 68 extends through the aligned openings 66 and through aligned passages 70 defined by body 62, for pivotably mounting the lower end of body 62 to and between mounting members 64. A plate 72 extends between and interconnects mounting members 64, and defines a sleeve 74, at its upper end. One end of an adjustment rod 76 is engaged within sleeve 74, and the opposite end of adjustment rod 76 is threaded and engaged with a knob 78 which bears against body 62. In a known manner, knob 78 and adjustment rod 76 are used to move resistance unit 60 into engagement with bicycle wheel 32.
Resistance unit 60 includes a pair of outer ears 80, which define aligned passages 82. A roller 84 is located between ears 80, and is carried by a shaft 86 that extends through an axial passage defined by roller 84. A bearing 88 is pressed into each passage 82 and engaged with a step defined by the passage 82, and shaft 86 extends through and is engaged with bearings 88 for providing rotation of shaft 86 and roller 84 relative to body 62.
Shaft 86 includes an extension 90 that extends outwardly of one of bearings 88, and a flywheel 92 that is secured to shaft extension 90. Shaft extension 90 includes a tapered section 94, which is received within a tapered passage 96 formed in flywheel 92. The end of shaft extension 90 is threaded, and a nut 98 is engaged with the threaded end of shaft extension 90 for retaining flywheel 92 on shaft extension 90. Nut 98 is received within a recess 99 defined by flywheel 92, and a cover 100 is received within flywheel recess 99 for enclosing nut 98 and providing a continuous outer surface of flywheel 92.
A magnetic resistance arrangement functions to provide resistance to rotation of flywheel 92, which is transferred through shaft 90 and roller 84 to resist rotation of bicycle wheel 32, to thereby provide resistance to a user during exercise using bicycle 24. The resistance arrangement is of the magnetic type, wherein a magnet and a rotating electrically conductive member function to establish eddy current resistance upon operation of bicycle training device 20.
In accordance with the present invention, a passage 102 is formed in body 62, and a magnet 104 is received within passage 102. In the illustrated embodiment, magnet 104 is mounted to a magnet carrier 106, which has a cross section corresponding to that of passage 102 such that magnet carrier 106 is slidably received in passage 102. Passage 102 opens onto a side surface 108 defined by body 62, such that the face of magnet 104 is exposed to the exterior of body 62.
An adjustment mechanism is interposed between body 62 and magnet carrier 106, for varying the position of magnet 104 within passage 102. The adjustment mechanism includes a shaft 110 that is engaged at one end with magnet carrier 106, and engaged at its opposite end with an actuator 112 which is located outwardly of a side surface 114 defined by body 62. Side surface 114 faces in a direction opposite that of side surface 108. The end of shaft 110 opposite magnet carrier 106 includes threads 116. Actuator 112 includes an external head portion 118 and a collar portion 120 that is received within a recess 122 extending inwardly from side surface 114 of body 62. Collar portion 120 includes an internally threaded passage 124, and threads 116 at the end of shaft 10 are engaged with threaded passage 124. A wall 126 is located between the inner end of passage 102 and the inner end of recess 122. The end of actuator collar portion 120, shown at 128 (
Resistance unit 60 further includes an electrically conductive member, in the form of a conductive plate 132, which is interconnected with flywheel 92. Conductive plate 132 defines a central opening 134 through which shaft extension 90 extends. Conductive plate 132 is oriented so as to be in alignment with the end of passage 102 that opens onto side surface 108 of body 62. A vane member 136 is mounted to flywheel 92, and conductive plate 132 is secured to vane member 136. Conductive plate 132 may be formed of any satisfactory metallic or non-metallic material that is electrically conductive, such as aluminum or copper.
In operation, rotation of bicycle wheel 32 is transferred to roller 84, which in turn imparts rotation to shaft 86 and flywheel 92, and conductive plate 132 and vane member 136 rotate along with flywheel 92. In a manner as is known, magnet 104 and conductive plate 132 interact to establish eddy current resistance to rotation of conductive plate 132 upon rotation of conductive plate 132. Such resistance to rotation of conductive plate 132 also resists rotation of flywheel 92, shaft 86 and roller 84, to thereby resist rotation of bicycle wheel 32.
The degree of resistance provided by magnet 104 and conductive plate 132 (i.e. the eddy current resistance established upon rotation of conductive plate 132 relative to magnet 104) is adjusted by varying the position of magnet 104 within passage 102, to vary the spacing between magnet 104 and conductive plate 132. To accomplish this, head portion 118 of actuator 112 is rotated, which functions to cause axial movement of shaft 110 within passage 102, to move magnet 104 inwardly or outwardly within passage 102 toward and away from conductive plate 132. Spring 130 functions to apply a constant outward bias on magnet carrier 106, to maintain end 128 of actuator collar portion 120 in engagement with the outwardly facing surface of wall 126. Magnet carrier 106 and passage 102 are preferably formed with a mating non-circular cross section, which resists rotation of shaft 110 when actuator head portion 118 is rotated, to cause such axial movement of shaft 110 due to the treaded engagement between shaft threaded end 116 and threaded passage 124 of actuator collar portion 120. Alternatively, the area of shaft 110 that extends through wall 126 may have a non-circular cross section, and the passage in wall 126 through which shaft 110 extends may be provided with a mating non-circular cross section, to prevent rotation of shaft 110 when actuator head 118 is rotated.
As shown in
Recess 122 in body 62 includes a side wall 142 having spaced apart grooves 144. Each groove 144 is configured to receive rib 140. As shown in
Actuator collar portion 120′ defines a recess 152 in its end that faces wall 126′, and a pair of wedge-shaped locating members 154 extend outwardly from sleeve 150 through recess 152. Collar portion 120′ defines a pair of arcuate side walls 156 that extend between locating members 154, which terminate in end edges 158.
As shown in
In operation, the adjustment mechanism of
In operation, vane member 136 functions to draw air inwardly upon rotation of flywheel 92, due to the orientation of vanes 176. The air is “scooped” by each of vanes 176 upon rotation, and is directed inwardly toward opening 170. This functions to move air against the inner surface of flywheel 92 within the spaces between spokes 174 and in the area exposed through opening 170. The air impinges on shaft extension 99, as well as the adjacent areas of body 62, and provides overall air flow in the vicinity of flywheel 92 during operation of resistance unit 60. This functions to provide an overall cooling effect on resistance unit 60.
While the invention has been shown and described with respect to certain embodiments, it is understood that various alternatives and modifications are possible and are contemplated as being within the scope of the present invention. For example, and without limitation, the present invention has been described with respect to movement of magnet 104 within passage 102 toward and away from conductive member 132, to vary the strength of the eddy current resistance to rotation of roller 84. It is also contemplated that magnet 104 may be stationarily mounted to body 62 in a fixed position, and that the position of conductive plate 132 on shaft 86 may be adjusted relative to the stationary magnet, to vary the strength of the eddy current resistance. It is also understood that a single magnet such as 104 may be employed as shown and described, or that resistance unit 60 may include any number of magnets. Further, it is understood that the illustrated adjustment mechanisms are representative of any number of mechanisms that may be employed to vary the position of magnet 104 within passage 102. While the illustrated adjustment mechanisms involve manual adjustment of the position of the magnetic member, it is also understood that the position of the magnet within the passage of the body may also be accomplished via a cable and actuator, or by an electrically operated adjustment mechanism. It is also understood that adjustment of the position of magnet 104 may be accomplished with a spring that biases in an opposite direction than spring 130, or that the spring may be eliminated entirely. In addition, it is also understood that the vane members, such as 136, 180, may be eliminated and that conductive plate 132 may be mounted directly to flywheel 92. While this arrangement does not provide the cooling effect that is accomplished when a vane member is used, it nonetheless provides a satisfactorily eddy current resistance mechanism for resisting rotation of shaft 86. It is also contemplated that flywheel 92 may be eliminated or may be located in a different location other than adjacent conductive member 132, e.g. interconnected with the opposite end of shaft 86. The presence of the rotating conductive member 132 adjacent magnet 104 functions to establish the eddy current resistance with or without flywheel 92.
In addition, it is understood that the rotating vane member, which provides a cooling function upon operation of the device, may be used in any type of resistance unit and is not limited to use in connection with a magnetic unit as shown and described. For example, a rotating vane member such as that shown in the drawings may be used in a fluid-type resistance unit or in an electronic resistance unit. In addition, while the rotating vane member is shown as being mounted to the flywheel, it is understood that the vane member may be mounted in any location for rotation with the shaft.
Various alternatives and embodiments are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter regarded as the invention.
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