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.
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.
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
The invention and is embodiments will become more clearly understood when referencing the detailed description against the figures, as follows:
A preferred embodiment of the invention is illustrated in
A top view of the preferred embodiment of the device is depicted in
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
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
As before, a side view of this embodiment is shown in
Because the method of propulsion is nonobvious/unintuitive, and yet fundamental to the invention,
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