ADAPTIVE EXERCISE DEVICE WITH INDEPENDENT MOTION

An adaptive exercise device provides a foot motion in which horizontal and vertical components thereof are mechanically decoupled and independent. The device includes a primary guide assembly, and a secondary guide assembly, and a first and a second foot link, each having a foot pad portion for receiving and supporting a user's foot. The primary guide assembly directs the foot pad portions along a first path of travel having a horizontal component of motion. The secondary guide assembly directs the foot pad portions along a second path of travel having a vertical component of motion. Further disclosed is a method of exercising through the use of the adaptive exercise device.

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Description
CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of U.S. Provisional Patent Application No. 61/453,751 filed Mar. 17, 2011, entitled “Adaptive Exercise Device with Independent Motion”, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to exercise devices, and more particularly to exercise devices which simulate a running and stepping motion. In particular, the invention relates to an adaptive exercise device configured and operable to mechanically decouple the vertical and horizontal components of the foot and leg motion so as to allow a user to independently control them during the use of the device.

BACKGROUND OF THE INVENTION

There are a variety of exercise devices which attempt to simulate a running and stepping motion in which a user's feet and legs travel along a path having vertical and horizontal components of motion. One group of such devices is termed “adaptive exercise devices”, and they allow a user to vary the degree of foot and leg motion while the device is in use. This invention is directed to a particular type of adaptive exercise device which decouples the vertical and horizontal components of motion so that the horizontal component of foot and leg motion is independent of the vertical component of the motion of the foot and leg.

As will be explained hereinbelow, the present invention allows a user to implement a solely vertical foot and leg motion or a solely horizontal foot and leg motion, or a foot and leg motion which is a blended ratio of the two components. The system of the present invention is of simple mechanical construction, and hence is reliable, easy to maintain, and low in cost. These and other advantages will be apparent from the drawings, discussion, and description which follow.

BRIEF DESCRIPTION OF THE INVENTION

Disclosed is an adaptive exercise device which includes a frame which is configured to be supported on a floor, a primary guide assembly, and a second guide assembly. The device further includes a first and second foot link, each foot link having a foot pad portion configured to receive a user's foot. Each foot link is disposed so as to engage the primary guide assembly which in turn is configured and operable to direct the foot pad portions of the foot links along a first path of travel having a horizontal component of motion. The foot links are further disposed so as to engage the secondary guide assembly which is configured and operable to direct the foot pad portions of each of said foot links along a second path of travel having a vertical component of motion. The device is configured so that the motion of the foot pads along the first path of travel is mechanically independent of the motion of the foot pads along the second path of travel. In one embodiment of the invention, the primary guide assembly includes at least one primary track which is configured and operable to engage and direct the first and second foot links along the first path of travel. The at least one primary track may be inclined relative to a horizontal support surface upon which the device is resting, and the degree of inclination may be made to be adjustable.

In other embodiments, the primary guide assembly includes a first and a second swing arm which are pivotally supported by the frame. Each swing arm is engaged in mechanical communication with a respective one of the foot links so as to at least partially support its respective foot links as it moves along the first path of travel. The swing arms in this embodiment may be pivotally coupled to their respective foot links at a connection point; and when the foot links move along the first path of travel, the connection points define an arc. In this embodiment, the secondary guide assembly may include a first and a second secondary guide track which engage respective foot links; and the secondary track may be curved so that the curvature of those secondary tracks corresponds geometrically to the curvature of the arc defined by the connection points between the swing arms and their respective foot links.

The secondary guide assembly may, in some embodiments, include a first and second track disposed in a parallel relationship with one another, together with a control system which is operative to move said first and second tracks along respective paths of travel having equal and opposite vertical components of motion while maintaining the secondary tracks in a parallel relationship. In this embodiment, the foot links in turn engage respective ones of said first and second secondary tracks so as to be displaceable along the length thereof so that when the secondary control system moves the secondary tracks along their respective paths of travel having the vertical component of motion, that vertical component of motion is communicated to a respective foot link so as to move the foot pad portion of that foot link along a second path of travel having the vertical component of motion.

In yet other embodiments, the secondary guide assembly may include a first and second swing arm, each being coupled to a respective one of the foot links. The secondary guide assembly will, in such embodiments, further include a control system which is operative to move the first and second swing arms along respective paths of travel having equal and opposite vertical components of motion so that when the secondary control system moves the swing arms along their respective paths of travel having the vertical component of motion, that vertical component of motion is communicated to a respective foot link so as to move the foot pad portion along a second path of travel. In some of such embodiments, the swing arms of the secondary guide assembly are each pivotally coupled to their respective foot links at a connection point whereby when the foot links move along the first path of travel, the connection point defines an arc. In these embodiments, the primary guide assembly includes at least one curved guide track which engages the foot links. This at least one track is curved so that the curvature thereof corresponds geometrically to the curvature of the arc defined by the connection points.

Also disclosed herein is a method of exercise comprising the use of the device of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a portion of an exercise device in accord with the present invention;

FIG. 2 is a front view of the device of FIG. 1 better illustrating the secondary guide assembly thereof;

FIG. 3 is a side view of a portion of an exercise device as shown in FIGS. 1 and 2 illustrating further components thereof;

FIG. 4A is a side view of a portion of an exercise device in accord with the present invention illustrating an alternative secondary guide assembly;

FIG. 4B is a top plan view of the device of FIG. 4A illustrating the secondary guide assembly;

FIG. 5 is a side view of a portion of another embodiment of exercise device in accord with the present invention;

FIG. 6A is a side view of portions of a further embodiment of exercise device in accord with the present invention;

FIG. 6B is a side view of an inverted embodiment of the exercise device of FIG. 6A;

FIG. 7A is a side view showing a further embodiment of exercise device of the present invention;

FIG. 7B is a front view of the exercise device of FIG. 7A better illustrating the secondary guide assembly thereof; and

FIG. 8 is a schematic illustration showing various paths of foot motion which may be achieved through the use of the adaptive exercise device of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention may be implemented in a number of different configurations and will be explained with regard to some specific embodiments. It is to be understood that other modifications and variations are within the scope of this invention and will be readily apparent to those of skill in the art in view of the teaching of this disclosure.

FIGS. 1 and 2 show portions of one particular embodiment 10 of exercise device of the present invention. It will be noted that for clarity of illustration, certain portions of the exercise device 10 are not illustrated in these figures. Referring now to FIG. 1, there is shown a side view of the device 10. As will be seen, the device includes a frame 12 which is configured to support various of the remaining components of the device on a horizontal support surface such as a floor. The frame 12 is typically fabricated from a relatively durable material such as a metal.

The device 10 of FIG. 1 further includes a primary guide, which, as will be explained hereinbelow, engages and supports a pair of foot links. In this embodiment the primary guide comprises a track assembly 14 defining at least one primary track member, and may comprise a single wide ramp or a pair of separate primary tracks. As shown herein, the primary guide track assembly 14 is inclined relative to the floor upon which it is supported, although in other instances it may be parallel to the floor or in particular instances may even be defined by the surface of the floor. It is to be noted that the primary guide track assembly may be made adjustable so that its angular relationship to a support surface can be varied.

The device 10 includes a secondary guide assembly 16 which in this embodiment includes a pair of secondary tracks 18a and 18b which are disposed in a parallel relationship and are pivotally supported on the frame 12. The secondary track assembly 16 also includes a secondary track control system 20 which operates to move the first and second secondary tracks 18a, 18b along respective paths of travel having equal and opposite vertical components of motion while maintaining them in a parallel relationship.

FIG. 2 is a front view of the device 10 better illustrating the secondary track control system. As will be seen from FIG. 2, the system includes a pair of rocker arms 24a, 24b which engage and support the secondary tracks 18a, 18b. The rocker arms 24a, 24b and associated tracks 18a, 18b are pivotally supported on the frame 12 by a shaft 26. The control system further includes a flywheel 22 and associated crank arm 28; and as will be seen, this system allows the tracks 18a, 18b to reciprocate in a primarily vertical direction of travel. Although the flywheel 22 is not essential to the operation of the device, it has been found that inclusion of a flywheel can smooth and stabilize the motion of the device and enhance its exercise value. Likewise, a variable resistance device such as a friction brake or an electromagnetic brake may be included in the device as is known in the art. It will be understood that the overall path of travel of the tracks will have a very slight curvature owing to the geometry of this particular implementation; however, the vertical component of the motion is predominant and hence this motion is referred to as having a primarily vertical component as is shown by arrow A in FIGS. 1 and 2.

Referring now to FIG. 3, there is shown further features of the exercise device 10 of FIGS. 1 and 2. The FIG. 3 illustration does not depict the frame or details of the secondary track control system. This is for purposes of clarity, although it is to be understood that these elements will be included in this embodiment. The FIG. 3 device does show a track assembly 14 of the primary guide as well as a secondary track 18 of the secondary guide. Further shown in FIG. 3 is a foot link 30, it being understood that an apparatus of this type will include a pair of such foot links. Foot links are typically fabricated from a durable body of material such as wood or metal and include a foot pad portion 32 configured to support a user's foot thereupon.

In this embodiment, the foot link 30 also includes a first roller 34 and a second roller 36. The first roller 34 engages a bottom surface of the secondary track 18, while the second roller 36 engages a top surface of the primary track 14. Other track and roller configurations may be implemented. As will be appreciated from the figure, the two rollers 34 and 36 cooperate with the tracks 14 and 18 and the frame (not shown) to support the foot link 32 so that when a user's foot is placed on the foot pad 32, the foot link will be stable. As will be seen, the track and roller arrangement allows for the foot link to move back and forth along a reciprocating path of travel having a primarily horizontal component of motion, as shown by arrow B. It will be appreciated from FIG. 3 that as the secondary track 18 moves in the vertical direction shown by arrow A, the component of vertical motion thereof is also transferred to the respective foot link 30 via the first roller 34 so as to pivot the foot link about the second roller 36 thereby vertically displacing the foot pad 32a along a path of travel having a vertical component of motion. In this manner, vertical foot motion will be achieved; and given the fact that the secondary track controller (20 in FIG. 1 and FIG. 2) synchronizes the motion of the secondary tracks, the motion of the foot pads 32a in a vertical direction will likewise be synchronized so as to be equal and opposite. It will be appreciated from the figure that the vertical motion of the foot as shown by arrow A and the fore and aft, horizontal motion of the foot as shown by arrow B are mechanically decoupled and hence independent of one another. Thus, through the use of the device of this invention, a user may independently control the vertical and horizontal components of foot motion.

In keeping with a further feature of the present invention, the fore and aft, generally horizontal, motion of the foot links 30 may be synchronized by a foot link control system which causes the foot links to move in equal and opposite directions along the primary track assembly 14. This may be accomplished through various mechanical arrangements as is known in the art. As is specifically shown in FIG. 3, control of the foot link motion is achieved by the use of a pair of swing arms, and one swing arm 40 is shown herein as being mechanically coupled to the foot link 30. It is to be understood that a second swing arm will likewise couple to a second foot link. In this embodiment the swing arms 40 are pivotally supported by the frame and mechanically coupled together through a geared joint 42 which is of a “differential” configuration and which provides equal and opposite motion of the two swing arms. Coupled swing arms of this type are shown, for example, in U.S. Pat. No. 7,794,362 the disclosure of which is incorporated herein by reference. The FIG. 3 embodiment also includes a handgrip portion 44 which projects from the swing arm and may be gripped by a user so as to provide for upper body exercise. It is to be noted that in this embodiment, the inclusion of swing arms is optional, and synchronization of the foot links may be achieved through other means or dispensed with. Also, as will be apparent to those of skill in the art, the FIG. 3 embodiment, like the other embodiments shown herein, may include a flywheel and/or resistance device in mechanical communication with the foot links.

The present invention may be implemented in yet other embodiments, and one such alternative embodiment is shown in FIGS. 4A and 4B. Specifically shown therein is a partial view of an exercise device 50 showing specific features thereof. FIG. 4A is a side view of portions of the device, and as will be seen, it includes a frame 12 and primary track guide assembly 14 as generally described with regard to the previous embodiment. Further shown in FIG. 4A is a secondary guide assembly 52 as operative to move associated secondary tracks 18a, 18b in a generally vertical direction. In this regard, the tracks 18a, 18b are supported by a pair of crankshafts 54a, 54b which are supported by the frame 12. The crankshaft 54b is also rotatably coupled to a flywheel 56 by a drive wheel 58 operating through a drive belt 60. FIG. 4B is a top plan view of the device 50 showing the secondary guide assembly 52. As will be seen from the figures, rotation of the crankshafts 54a, 54b displaces the guides 18a, 18b along a path of travel having a substantially vertical component of motion as shown by arrow A. As in the previous embodiment, foot links are mechanically engaged with the secondary tracks 18a, 18b so that vertical displacement of the tracks 18a, 18b reciprocates the foot pad portion of the associated foot links in a vertical direction.

Yet another embodiment of exercise device of the present invention is shown at reference numeral 70 in FIG. 5. This embodiment is generally similar to the embodiment 10 shown in FIG. 3, except that is of an “inverted” structure. In that regard, the relative positions of the primary guide and secondary guide are reversed. Specifically, the device of FIG. 5 includes a frame 12, shown partially cut away herein for purposes of clarity. The device 70 of FIG. 5 includes a primary guide assembly 14 having a track portion thereof suspended from the frame 12 in a spaced apart relationship with the floor. The secondary guide assembly includes vertically displaceable tracks 18a, 18b as previously described, and these tracks may be reciprocated in a substantially vertical path of travel, as shown by arrows A, by a control system which may be similar to that shown with regard to the embodiment 10 of FIGS. 1-3 or the embodiment 50 of FIGS. 4A and 4B.

The device 70 of FIG. 5 further includes a first and a second foot link 30a, 30b, and each foot link includes a foot pad portion 32a, 32b as previously described. As in the FIG. 3 embodiment, the foot links have swing arms associated therewith; and will be seen in FIG. 5, swing arm 40b is associated with foot link 30b. A corresponding swing arm is associated with foot link 30a; however, it is hidden from view behind swing arm 40b. As mentioned with regard to the FIG. 3 embodiment, the swing arms 40 are not essential to this embodiment but their inclusion does provide for upper body exercise and can serve to synchronize the motion of the foot links.

In the FIG. 5 embodiment 70, a first roller 34b is disposed at a front end of the foot link 30b and it engages the first guide track member 14. A corresponding first roller is associated with foot link 30a but is not visible in this drawing. A second roller 36b associated with the foot link 30b engages the secondary track 18b while a corresponding second roller 36a associated with the first foot link 30a engages the secondary track 18a. As in the previous embodiments, this combination of tracks and rollers provides for a fore-aft, generally horizontal path of travel B of the foot links 30 and their associated foot pads 32.

In the various embodiments of FIGS. 1-5, the primary guide includes one or more tracks 14, and the secondary guide includes two tracks 18a and 18b. As will be seen from these figures, the primary tracks 14 are straight tracks and are in a generally parallel relationship with the secondary tracks 18a and 18b which are also generally straight. It has been found that this parallel relationship assures that the fore-aft motion of the foot pads 32, has a primarily horizontal component. An equivalent motion may be achieved through the use of geometrically corresponding curved tracks as will be discussed herinbelow. This parallel and/or geometrically corresponding relationship is not essential to the operation of the devices of the present invention, and may be deviated from in some other embodiments so as to modify the foot action in the for-aft direction by adding some vertical component thereto, while still allowing the user to independently augment, or subtract from the net vertical motion of the foot pads 32.

Referring now to FIG. 6A, there is shown yet another embodiment 80 of exercise device in accord with the present invention. In this embodiment, the primary guide does not include any type of track member but is comprised of a pair of swing arms 40 of which one arm 40b is shown herein, the other arm being disposed there behind. The swing arms 40 support their respective foot links 30a, 30b at a front end thereof, and reciprocation of the swing arms 40 moves these front ends in a reciprocal, slightly curved path of travel as shown by arrow B, which path of travel has a substantially horizontal component of motion. The second ends of each foot link are supported by curved track members 18a, 18b associated with a secondary guide assembly. As in the previous embodiments, these tracks are reciprocated along a substantially vertical path of travel as shown by arrow A by a control system, not shown. It is to be understood that this control system will typically be supported by the frame 12 of the exercise device and may be in accord with secondary control systems previously described or other secondary control systems as may be apparent to those of skill in the art.

Referring now to FIG. 6B, there is shown another embodiment 90 of exercise device of the present invention. This embodiment corresponds generally to the embodiment of FIG. 6A insofar as the primary guide assembly is constituted by swing arms, such as swing arm 40b; however, the structure of the FIG. 6B device 90 is “inverted” with respect to that of FIG. 6A. Specifically, the secondary guide assembly is moved to the front of the device so that the curved tracks 18a, 18b thereof are engaged by first rollers 34a, 34b associated with corresponding foot links 30a, 30b. The geometry of the FIG. 6B embodiment 90, like that of the FIG. 6A embodiment 80, provides for independent horizontal and vertical motion of the user's feet.

In embodiments of the type, shown in FIGS. 6A and 6B, the secondary tracks 18a, 18b are preferably curved and in the depicted embodiments, the curvature of these tracks 18a, 18b corresponds, geometrically, to the curved path of travel B of the front ends of the foot links 30a, 30b. The geometrically corresponding paths of travel need not be congruent; but, they will have the same overall shape and curvature even though their sizes may differ. By maintaining such corresponding curvatures, the fore-aft motion of the foot pads 32a, 32b and a user's foot associated therewith is generally horizontal as is the case when a system of guides based wholly on tracks is utilized as discussed with regard to FIGS. 1-5 above. And, it should be noted that in view of the teaching of FIGS. 1-5, it will be apparent to one of skill in the art that the tracks of the FIGS. 6A and 6B embodiments need not correspond geometrically and/or be curved.

Referring now to FIGS. 7A and 7B, there is shown yet another embodiment 100 of exercise device in accord with the present invention. In this embodiment, the primary guide assembly includes a track member 14 which as previously described may be a single or a double track. In this embodiment, the secondary guide assembly provides vertical motion to the foot links 30a, 30b by means of associated swing arms 40a, 40b coupled thereto.

FIG. 7B shows a front view of a portion of the device 100 illustrating swing arms 40a, 40b which are coupled to a rocker arm 102 by ball-and-socket connectors 104a, 104b, although it is to be understood that other types of universal joint couplings may be similarly employed. The rocker arm 102 is pivotally supported on the frame 12, and is reciprocated by a flywheel 20/crank arm 28 arrangement coupled thereto. As will be seen, reciprocation of the rocker arm 102 will cause the associated swing arms in to reciprocate along a path of travel having a significant vertical component of motion as shown by arrow A.

Referring back to FIG. 7A, it will be seen that reciprocation of the swing arms 40 in the vertical direction of arrow A raises and lowers the front end of the foot link 30. The foot link 30 is in turn supported on the track 14 by a roller 32 so that the vertical reciprocation of the front end of the foot link 30 causes the associated foot pad 32 to likewise move in a reciprocal, vertical path A. It will be further seen from FIG. 7A that the foot link 30 is also capable of moving along the track 14 so as to provide substantially horizontal motion to the user's foot.

In the embodiment of FIGS. 7A and 7B, the track 14 is curved, and in specific embodiments, the curvature of the track may correspond geometrically to an arc defined by the pivotal connection of the swing arm 40 to the foot link 30. And, as with regard to the previous embodiments, other arrangements, such as the use of a straight track, or a non-geometrically corresponding track may be alternatively employed.

In all of the embodiments of the present invention, vertical and horizontal components of foot motion are mechanically decoupled, and FIG. 8 illustrates some paths of foor travel which can be achieved as a result of that decoupling. For example, a user may employ an exercise device of the present invention so as to move his or her foot in a path of travel which is substantially vertical, as is shown by arrow A in FIG. 8, without necessarily moving his or her foot in a substantially horizontal path of travel, as is shown by arrow B in FIG. 8. Likewise, horizontal motion may be implemented without utilizing any vertical motion. Through the use of the devices of the present invention, it is also possible to generate a foot action which is a blend of the horizontal and vertical components as further shown in FIG. 8 by arrows C, D, E and F.

The fact that the vertical and horizontal components of foot motion are mechanically decoupled also allows for a user to make changes to the foot path while the device is in use. For example, in a typical exercise regimen, a user may initially elect to employ a strictly vertical, up and down foot motion akin to that achieved by the use of a stair stepper device. Subsequently the user may add a horizontal component of motion so as to elongate the stride, eventually achieving an elliptical path. The user may then decrease the vertical component so as to implement a strictly horizontal motion akin to that achieved through a cross country skiing simulator.

The present invention may be implemented in a number of other embodiments which will be apparent to those of skill in the art in view of the teaching presented herein. The foregoing drawings, discussion, and description are illustrative of specific embodiments of the invention but are not meant to be limitations upon the practice thereof. It is the following claims, including all equivalents, which define the scope of the invention.

Claims

1. An adaptive exercise device comprising:

a frame configured to be supported on a floor;
a primary guide assembly;
a secondary guide assembly;
a first and second foot link, each foot link having a foot pad portion configured to receive a user's foot, each of said foot links being disposed so as to engage said primary guide assembly, which is configured and operable to direct the foot pad portions of said foot links along a first path of travel having a horizontal component of motion, each of said foot links being further disposed so as to engage said secondary guide assembly, which is configured and operable to direct the foot pad portions of said foot links along a second path of travel having a vertical component of motion, wherein the motion of said foot pads along said first path of travel is mechanically independent of the motion of said foot pads along said second path of travel.

2. The exercise device of claim 1, wherein said primary guide assembly includes at least one primary track which is configured and operative to engage and direct said first and second foot links along said first path of travel.

3. The exercise device of claim 2, wherein said primary guide assembly includes two primary tracks, each primary track being configured to engage a respective one of said foot links.

4. The exercise device of claim 2, wherein when said device is supported on a horizontal surface, said at least one primary track is inclined relative to said horizontal surface.

5. The exercise device of claim 1, wherein said primary guide assembly includes a first and a second swing arm which are pivotally supported by said frame, each swing arm being engaged in mechanical communication with a respective one of said foot links, wherein said swing arms at least partially support their respective foot links as they move along said first path of travel.

6. The exercise device of claim 5, wherein each swing arm is pivotally coupled to its respective foot link at a connection point, whereby when said foot links move along said first path of travel, said connection points define an arc; and wherein said secondary guide assembly includes first and second secondary guide tracks which each engage a respective one of said foot links, and wherein said secondary tracks are curved so that the curvature of said secondary tracks corresponds geometrically to the curvature of the arc defined by said connection points.

7. The exercise device of claim 5, wherein said swing arms are pivotally supported on said frame so that a first end of said pivot arms can travel in a reciprocal path relative to said frame, said first and second pivot arms being mechanically coupled together so that the reciprocal path of travel of said first swing arm is equal and opposite to the reciprocal path of travel of said second swing arm.

8. The exercise device of claim 1, wherein said foot links engage the primary guide assembly and/or the secondary guide assembly via a roller.

9. The exercise device of claim 1, further including a flywheel and/or a variable resistance device in mechanical communication with said foot links.

10. The exercise device of claim 9, wherein said flywheel and/or variable resistance device is in mechanical communication with said foot links via said primary guide assembly.

11. The exercise device of claim 9, wherein said flywheel and/or variable resistance device is in mechanical communication with said foot links via said secondary guide assembly.

12. The exercise device of claim 1, wherein said secondary guide assembly includes a first and a second secondary track disposed in a parallel relationship with one another, and a control system operative to move said first and second secondary tracks along respective paths of travel having equal and opposite vertical components of motion while maintaining said secondary tracks in a parallel relationship; wherein said foot links each engage a respective one of said first and second secondary tracks so as to be displaceable along the length thereof wherein when said secondary control system moves said secondary tracks along their respective paths of travel having said vertical component of motion, said vertical component of motion is communicated to a respective foot link so as to move said foot pad portion along said second path of travel having said vertical component of motion.

13. The exercise device of claim 1, wherein said secondary guide assembly includes a first and a second swing arm, said swing arms each being coupled to a respective one of said foot links, said secondary guide assembly further including a control system which is operative to move said first and second swing arms along respective paths of travel having equal and opposite vertical components of motion wherein when said secondary control system moves said swing arms along their respective paths of travel having said vertical component of motion, said vertical component of motion is communicated to a respective foot link so as to move said foot pad portion along said second path of travel.

14. A method of exercising comprising the use of the exercise device of claim 1.

Patent History
Publication number: 20120238408
Type: Application
Filed: Oct 14, 2011
Publication Date: Sep 20, 2012
Inventor: Larry D. Miller (Rochester, MI)
Application Number: 13/273,524
Classifications
Current U.S. Class: Stair Climbing (482/52)
International Classification: A63B 22/04 (20060101);