Individual foot-skates for transportation, exercise, and sport

Abstract

A small skate device is described which in the user is supported and transported by two of such skates, one under each foot. Each skate has three or four wheels, one or two per axle of each device. Each wheel is mounted on the axles with at least one bearing. The two axles of the skates are supported on angled pivots so as to cause the skate to turn when the upper surface is angled with respect. to the ground. The upper surface, or deck, has either frictional material applied to the top face, small spring release bindings, or straps to hold the user's foot in place.

Description

REFERENCES CITED

5984328	November 1999	Tipton
6065762	May 2000	Brelvi
6382640	May 2002	Killian
6572120	June 2003	Chang
6913270	July 2005	Wang
20060055137	March 2006	Jiang
7059613	June 2006	Farrelly

FIELD OF THE INVENTION

This invention relates to human-powered wheeled transportation device where each foot is supported by one device, as with in-line skates, roller skates, or heeling shoes (U.S. Pat. No. 6,913,270 and similar). The invention also relates to skateboards and other devices rode sideways.

BACKGOUND OF THE INVENTION

The present invention is a personal transportation device that inherits traits from both the enormously popular sports of in-line skates and skateboarding. Like in-line skates, each foot can move independently; like skateboarding, the skates are steered with axial deck roll. The present invention takes the advantages of both and merges them into a light, small pair of skates that are rode sideways and need only to be secured to the feet with friction.

Like both skateboarding and in-line skating, there exists the possibility that this type of locomotion will become very popular because the unusual structure of the involved motions attracts attention, is good exercise, and is fun. Presently a similar device exists on the market, ‘freeline skates’, U.S. Pat. No. 7,059,613. This invention is dissimilar and improves on the idea embodied therein. While the user's motion with both this invention and previous art is ostensibly similar, this invention is better in four notable ways:

1. It makes used of natural vestibular-spinal reflexes for balance, unlike previous art. When a person is standing normally, tipping forward induces the vestibular channels of the ear to activate the calf muscles to induce a righting force to correct the lean. When a user is riding the stated invention, this natural reflex—ankle extension—causes the deck to tilt in the direction of lean, forcing the board to turn; while moving forward this turn makes the skate and foot closer to the user's center of gravity. Thus, the system is actively stable. Compare this to previous art, where the user must torque the feet to correct for imbalance problems. This motion is less natural, less reflex-based, and therefore harder to learn. However, the presence of the deck-roll turning mechanism does not preclude torque-based turning as in previous art; it only augments it. With this invention, you can do both.

2. The use of four wheels on two axles with elastomeric or spring return enables the novice to stand on the skates more easily than with previous art. The acceptance of a new sport or technology is limited by how easily it can be learned, and this invention improves on this limiting step.

3. The use of axially aligned wheels causes the wheel axis to be parallel to the ground, hence more wheel surface touches the ground at a given time. In previous art two wheels are angled to the ground while turning and pumping. This causes a smaller contact patch with the riding surface, which, due to the elastomeric nature of the wheels, permits slight motion perpendicular to the plane of the wheel. This both adds friction due to wheel flexing and reduces the work done by pumping the devices. The present art is not subject to this mode of give/slight sliding when large, wide wheels are used, therefore improving efficiency. Wide wheels—as used in racecars—also increases the maximum tangential friction of the wheel upon the riding surface, improving cornering, ability to pump the device, and overall feel. However, if the user desires this type slight sliding and give from the skates, one simply has to replace wide wheels with more narrow ones, e.g. from an in-line skate.

4. The axial alignment of the wheels permits them to transition to a vibrational mode of sliding when pushed beyond the maximum sustainable tangential force. This permits large controlled skids as used in street luge and high-speed downhill skateboarding for deceleration and controlled cornering.

Like U.S. Pat. No. 7,059,613, this invention offers notable advantages over in-line skates, namely a smaller, more portable size and the ability to quickly put them on. With the embodiment described in claim 2, the user only needs to place his or her feet on the skates and push off—there is no need to strap a boot or anything else on. Similarly, the device is substantially smaller than most skateboards, making it more portable and possibly more socially acceptable.

SUMMARY OF THE INVENTION

The invention describes a number of designs for skates which are rode in tandem with one on each foot. That is, the user's shoulders and hips are on average approximately parallel to the direction of motion and the user's feet are approximately perpendicular to the long axis of each skate and hence parallel to the wheel axles. In all embodiments of the invention, the device is steered by either axial (that is, perpendicular to the length of the foot) rotation of the deck, as by ankle flexion and extension, or by torquing the individual skates about the leg.

In one embodiment of the invention, the skate comprises four wheels, two per axle, on opposite sides of an angled pivot. The angled pivot permits axial deck roll to be transferred to wheel deflection, permitting the devices to be steered. This rotation can be restrained by springs or elastomers. In this embodiment, as in the following two, the users foot can be attached to the skate with simple frictional tape, straps, or spring-loaded bindings used in bicycles or snowboards.

In a second embodiment of the invention, one of the axles (and hence two wheels) are replaced with a single wheel axle combination mounted rigidly to the frame, so the axle is parallel to the deck. Hence, as the deck rotates with respect to the ground, so does the rear wheel.

In a third embodiment, the front axle is not mounted on an angled pivot, and instead turning is accomplished through cable-coupled steering of the back wheel. Here the back wheel is mounted on an axle, which is in turn mounted to a frame that is allowed to rotate about a vertical pivot. Rotation about this vertical pivot is coupled to deck axial roll, and hence steering, through a pulley on the front pivot.

The skates, in all embodiments, are propelled by moving the legs and ankles with a scissor kick. With adequate practice the dynamics of the skates are readily internalized, and the user can quickly accelerate and climb hills on the devices without ever touching the ground (see FIG. 8 and associated description). Propulsion can be remarkably efficient, as the applied forces, though roughly perpendicular to the direction of motion, are parallel to the natural kicking motion of the legs; compare this to in-line skates, where the direction of propulsive force is parallel the shoulders, and the user has to pick up the boot on every stroke. While the propulsive force while using this invention is not as high as that with in-line skates or while pumping a normal skateboard, the overall motion is much smoother with little associated impact stress, thus providing utility to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and is embodiments will become more clearly understood when referencing the detailed description against the figures, as follows:

FIG. 1 illustrates a person using the skates;

FIG. 2 shows the skate described in claims 1, 2 & 3, as viewed from the top;

FIG. 3 shows a side view of the skate in FIG. 2;

FIG. 4 shows the skate described in claim 5, as viewed from the top;

FIG. 5 shows a side view of the skate in FIG. 4;

FIG. 6 shows the skate described in claim 6, as viewed from the top;

FIG. 7 shows a side view of the skate in FIG. 6;

FIG. 8 illustrates a preferred method for propelling the devices.

DETAILED DESCRIPTION

A preferred embodiment of the invention is illustrated in FIG. 1 with a user propelling himself with the devices 1. In this illustration, the foot platforms 2 have side rails 3′ to keep the users foot from hitting the wheels 4. The user is practicing the preferred method of movement depicted in FIG. 8.

A top view of the preferred embodiment of the device is depicted in FIG. 2. As the device depicted is symmetric about the vertical and horizontal axis, for clarity only one of a pair or set of four elements will be annotated. Foot surface, or deck, 2 is preferably covered in a frictional tape as used in skateboards and should be wide enough so the side rails 3 can accommodate a users shoe 5. The deck and side rails are shown here attached to the base with screws, though the entire assembly can be cast or molded as one piece. As before, there are four wheels 4 represented here in cutout to show the ball bearings 6 etc. The wheels are mounted on axles 7 lathed or otherwise shaped to provide a flat inner surface for the bearing 8 as present in skateboard trucks. The bearings are tightly secured to the axle with a spacer 15 and nut 16; rigid fixation of the wheel-bearing system decreases vibration, increases predictability, and increases the wheel's tangential friction. The wheels can be standard skateboard wheels, preferably high-rebound urethane 9 on a rigid plastic or metal core 10, though in-line skate wheels or similar also work well.

The axles, in turn, are mounted on angled pivots 11. Vibration about this pivot is restricted with compression springs, 12 e.g. Belleville springs or similar. These angled pivots are mounted to the frame and deck 18, as shown by bolts 13 or in a similar manner. This mounting includes a nut and threaded block, 19, to permit a variable amount of tension to be applied to the compression springs hence effecting variable frictional damping of rotation about this point. The axles rotate on the angled pivots via hardened collets, 21, which are welded or cast on. Rotation about the angled pivots is also restricted via torsional springs 14 which restores the deck to a horizontal position—and hence returns the skate to linear motion (no turn)—when no axial torque is applied by the user's foot. The torsional springs are oriented so as to generally assist the users calf and arch muscles, as these must support the riders weight while skating.

There are several ways of mounting the user's foot to the deck. The simplest is to just use frictional tape as in skateboards, thus allowing the user to jump off the skates at any time. It has been found that the space between the siderails, 3, should be set to tightly match the width of the users foot, 17. To jump with the skates on, holes are provided for bicycle or snowboard style bindings, 20. Holes are also provided in the siderails, 22, for attaching straps to hold the skate to the foot.

A side view of this skate is depicted in FIG. 3. All numbers are as in FIG. 2. This figure is symmetric about the vertical axis (except for the foot). The wheels 4 and bearings 6 are not rendered in cutout here as FIG. 2. Note the side-view allows a clear look at the angled pivot mounting 13. To increase the friction applied by the Belleville spring 12, the angled pivot is screwed further into the threaded block 19, and the set-point is locked with the associated nut. The deck 2 may be curved concave up like a skateboard via spacing elements 23 between it and the siderails, 3.

FIG. 4 depicts a skate where one axle-wheel and angled pivot set have been replaced by a fixed wheel 24 on a fixed axle 25. Note most of the redundant components will not be annotated on this figure. The axle is secured to the frame 18 via an extension 26 or similar. A small curved bumper 27 may be included for convenience (if the wheels of the two skates hit together hard during riding, the user may fall). A side view of this embodiment is shown in FIG. 5 with the same numbering scheme.

FIG. 6 shows a third embodiment of the invention. In this skate, axial deck roll is translated to varying turning radius via a cable and a set of pulleys. Here the rear pivot 28 is parallel to the ground and deck 2, while the front pivot 29 is perpendicular to the deck. The rear pivot is attached to both the axle 7, which holds the two rear wheels as described in FIG. 2, and to a pulley 30. On the front of the device, a wide wheel with a hemispherical cross section 31 is mounted on an axle 32 with bearings. The axle is mounted to a frame 33, which allows it to rotate about the front pivot 29. A closed cable loop 34, preferably of steel, is wound around the rear pulley 30, two idler pulleys 35, and a groove cut in the front wheel frame 33. This cable translates axial deck roll to varying turning radius. The cable is held under tension by a extension spring 36 mounted as shown. Cylinders of aluminum 37 are crimped onto the cable to keep the tension spring from slipping.

This also allows the spring to effect a torque restoring the deck to parallel to the ground, as rotation (in either direction) of the rear pulley will cause the spring to extend. Rear pulley 30 need not be circular; and ellipsoidal pulley will allow a nonlinear relationship between deck roll and turn, to provide stability at speed when the deck is nearly horizontal. The front pivot 29, rear pivot 28, siderails 3, deck 2, and idler pulleys are all mounted to a frame 38 as shown. The interface to the user's shoe, including frictional surface, holes for straps, and holes for bindings, is identical to that described in FIG. 2; this mechanism differs in the way that it transduces the deck roll to a change in direction while effecting an approximately identical mechanical interface to the user.

As before, a side view of this embodiment is shown in FIG. 7 with the same numbering scheme.

Because the method of propulsion is nonobvious/unintuitive, and yet fundamental to the invention, FIG. 8 provides a graphical description of the skates' use and the forces involved in propulsion.

The user preferably pushes off and starts moving on the skates by putting the rear toe to the ground. Once moving, the skates are propelled by moving each foot in an oppositely phased sinusoidal motion, as illustrated in FIG. 8. This mechanism of propulsion is similar to that employed for U.S. Pat. Nos. 5,984,328, 7,059,613. and U.S. published patent 20060055137. Since the turning of each skate is independently controlled by the flexing and extending each ankle, driving the skates in horizontal sinusoids while moving forward requires complementary flexion and extension of ankles. This motion is loosely related to that employed in walking, therefore is hypothetically already embedded in the central pattern generators of the spinal cord and hence is natural. By forcing the sinusoids that each foot is moving in—that is, pushing out while the foot is moving away from the body and pulling in while it is moving in—it is possible to do work and accelerate. Similarly, it is possible to slow down by exerting force on the opposite phase of the sinusoidal motion of the feet on the skates. This is only the first order description of what is possible with the skates, and by no means bounds all what is possible, but should be considered an outline of the primary mode of operation of the device: by applying force that is either approximately parallel (for acceleration) or anti-parallel (deceleration) to the tangential velocity of each skate. In FIG. 8 the black arrows 1, 2 emminating from the center of the feet indicate the force applied by the feet. During the sections of the cycle 3 and 4 the user applies net rightward force in such a way that friction accelerates him to the left. This force, less the force required from keeping the legs from doing a split, must be parallel to the axles otherwise the distance between the feet will change. During section 5 of the cycle, the user is decelerating by pushing outward on the skates, as indicated by 6 and 7, as they move inward. Note also that the sinusoids need not be 180 deg out of phase in order to accelerate or decelerate in this way—in practice it has been found ˜120 deg delay of the rear foot with respect to the front foot gives the most power. Also note that when starting, the user may torque the skates about the axis of the tibia/fibula to decrease turning radius and improve power at low speeds. Similarly, the skates may be torqued to control motion during sliding.

Claims

1. A small skate comprising:

four wheels, with two of each attached to the two axles of the skate;

a flat or slightly concave surface for resting the user's foot upon, or ‘deck’;

a set of angled pivots for supporting the axles and allowing them to rotate both with respect to the deck and with respect to the direction of motion for the purpose of steering;

a means of optionally damping rotation about these axle-pivots, and optionally providing elastomeric, spring, or cam-based return-to-center torque;

a means of optionally adjusting the angle of these pivots to change the turning characteristics of the devices;

finally, a frame which is fixed with respect to the deck for supporting these pivots.

2. A small skate as in claim 1 where frictional tape, as used in skateboards, or any other frictional treatment is applied to the top surface of the deck of the device. The friction between this and the user's normal shoe allows the foot to remain fixed to the skate while maneuvering. In this embodiment it is necessary to include vertical rails on either side of the shoe to prevent the shoe from hitting the wheels on the front and back of the skate.

3. A small skate as in claim 1 where the user's foot is secured to the deck with one or more straps placed over the top and/or back and/or front of the users shoe to limit movement of the skate during maneuvers, and to permit jumping with the skates.

4. A small skate as in claim 1 where the user's foot is secured to the skate with one or more spring-loaded bindings, for example those presently employed in bicycles or snowboards.

5. A small skate, similar to claim 1, but having three wheels, where the back wheel is allowed to rotate on an axle fixed with respect to the frame of the skate, this axle being approximately parallel to deck and parallel to the user's foot. The front two wheels, in turn, are mounted on an axle, as in claim 1, that is free to turn about an angled pivot. The pivot may be spring-loaded and dampened as in claim one. In effect, this is similar to the embodiment of claim 1 with the rear axle and associated two wheels replaced by a single wheel affixed to the frame.

6. A small skate, similar to claim 1, but having three wheels. Two of the wheels are mounted with ball bearings on an axle, and this axle is mounted on a free, spring-loaded, or dampened pivot as in claim 1. However, the axle here is not angled, so that rotation of the deck surface with respect to the ground does not effect a rotation of the axles with respect to the direction of motion. The third wheel freely turns on an axle which is in turn mounted on an approximately vertical pivot to allow the wheel to turn with respect to the direction of motion. The rotation of the rear axle about the horizontal pivot is translated to rotation of the front wheel about the vertical pivot through a belt running around pulleys on each pivot and at least two auxiliary pulleys.