This invention relates to conversion of energy resulting from foot movement. Foot movement, in particular, movement resulting from walking, running, skating, or cardiovascular exercise in general, usually involves alternately lifting and moving one foot relative to the other. It is an object of this invention to utilise the potential energy from such lifting movement.

In accordance with the present invention there is provided a device for producing rotational energy from foot movement, comprising a first member forming a support for a user's foot and arranged for pivotal movement relative to the second member, and a crank mechanism operatively coupled to the first member and including a drive wheel having an axis of rotation in fixed relation to the second member, the crank mechanism being such that a driving stroke of the foot of the user, resulting in pivotal movement of the first member relative to the second member is translated into rotational motion of the drive wheel.

In another aspect there is provided a device for producing rotational energy from foot movement, comprising a first member forming a support for a user's foot, with the exception of toes and at least a portion of a ball of the foot, and arranged for pivotal movement relative to a second member that forms a support for the user's toes and the other portion of the ball of the foot, the first member at the ball end being coupled to the second member at the ball portion, a crank mechanism operatively coupled to the first member and including a drive wheel having an axis of rotation in fixed relation to the second member, the crank mechanism being such that a driving stroke of the foot of the user resulting in pivotal movement of the first member relative to the second member is translated into rotational motion of the drive wheel, and a restoration means arranged to bias the first member away from the second member and thereby assist in restoring the first member to a remote position relative to the second member after a driving stroke of the foot and thereby assist the drive wheel to turn a full circle after a full driving stroke of the foot.

Preferably the device forms part of an-line skate, roller skate or the like whereby the drive wheel is coupled to a shaft of a wheel of the skate such that potential energy of the user's heel being lifted during skating is converted into rotational movement of the

drive wheel, and thereby the skate wheel, upon subsequent lowering of the heel for a driving stroke of the foot. Preferably, the drive wheel is coupled to the shaft of the wheel of the skate via a gear or a freewheel assembly, whereby rotational movement of the drive wheel is transmitted to the skate wheel only during rotation of the drive wheel in a first direction so as to effect rotation of the skate wheel in a second direction, and whereby the skate wheel freely rotates in the second direction.

Preferably the pivotal angle of the first member relative to the second member is less than 90°. In another aspect, there is provided a skate comprising the above described device.

Alternatively, the device can instead be applied to an electric generator or the like, wherein the rotational motion of the drive wheel is used to drive the generator via a gear or freewheel assembly, and the device can instead be applied to an exercise machine, wherein the rotational motion of the drive wheel is used to drive the electric generator or the like via a gear or freewheel assembly.

Preferably the first member is integrally formed with a boot for receipt of the user's foot and the drive wheel is located laterally and externally of the boot.

Preferably, the drive wheel is carried by a mount secured to a lateral part of the second member. Preferably the device includes restoration means arranged to bias the first member away from the second member and thereby assist in restoring the first member to a remote position relative to the second member after a driving stoke of the foot.

Preferably the restoration means includes a crank arm and a spring fixed between the second member and the drive wheel . Preferably the crank arm and the spring are fixed between the second member and an outward facing side of the drive wheel on which the fixing point of the spring is rotatable to the drive wheel.

Preferably the axial direction of the spring extends to the centre of the drive wheel when the device is in a rest state and the crank is up in a position between a dead angle position in which the first member can't turn or move the crank and a 12 o'clock position.

Alternatively, the spring is fixed between the second member and the crank mechanism, and a stopper is provided to prevent the crank in use passing through a right angle to the first member when the first member is in a remote position relative to the second member.

Preferably the crank mechanism further includes a crank for transmitting movement of the first member to the drive wheel, the crank having one end thereof axially fixed to the drive wheel and the other end thereof supporting the first member.

Preferably the crank supports the first member on a rotatable sleeve mounted to the end thereof, the rotatable sleeve being adapted to roll along the first member during pivotal motion of the first member relative to the second member.

Alternatively, the rotatable sleeve may instead be in the form of at least one bearing or a shaft, adapted to roll or slide along the first member during pivotal motion of the first member relative to the second member. Preferably a shoe comprises a device and the rotational motion of the drive wheel is used to drive a freewheel of an electric generator arranged in a heel of the shoe.

The invention will now be more fully described, by way of non-limiting example only, with reference to the accompanying drawings in which:-

Figure 1 is a side view of a skate comprising a device in accordance with the present invention;

Figure 2 is a side view of the skate of Figure 1 , showing a drive wheel of the device rotated by a driving stroke of a foot;

Figure 3 is a diagrammatic exploded perspective view of the device of Figure 1;

Figure 4 is a side view of a shoe comprising the device in accordance with the present invention; and

Figure 5 is a side view of the skate of Figure 1, showing an alternative arrangement for a restoration means.

The device 1 comprises a first member 2 in the form of a foot plate 3, pivotally connected at hinge 51 to a second member 4 forming a base plate 5, and a crank mechanism 6 for converting pivotal movement of foot plate 3 relative to base plate 5 into rotational movement of a wheel 7 that forms part of the crank mechanism 6. The

connection of the foot plate 3 to the base plate 5 is such that a toe 26 and possibly a portion of a ball of a foot of a user can rest on a toe platform 20 of the base plate 5 during use of the device. The arrangement of the platform 20 is also such as to provide a stop to prevent the foot plate 3 pivoting past a predetermined angle, say 80°, with respect to the base plate 5.

The wheel 7 is supported by mount 8 that is itself arranged laterally of the base plate 5 so as not to obstruct pivotal movement of the foot plate 3. The axis of the wheel 7 is, therefore, in fixed relation to the base plate 5. Rotation of the wheel is effected by crank 9, which has one end 10 axially mounted and keyed to wheel 7. In particular, the end 10 of crank 9 receives an end of an axially extending boss 22 of wheel 7, the boss 21 itself being supported in support 8 via a bearing 11. The second end 12 of the crank 9 carries a shaft 13 upon which is mounted to a rotatable sleeve 14. The sleeve 14 is adapted to rotate relative to shaft 13 whereby to provide for relative movement between the end 12 of the crank and the foot plate 3. Alternatively the shaft itself may be rotatably mounted in the crank 9, whereby to dispense with the need for sleeve 14, or formed of a suitable material having a frictional co-efficient sufficient to allow sliding movement relative to the foot plate 3 . Any other suitable bearing may also be used for this purpose. A downward force on the foot plate 3 will therefore, result in the end 12 of the crank 9, and thereby wheel 7, moving in a clockwise direction, as viewed in Figure 1 to render the device in the condition shown in Figure 2. In order to facilitate initial rotation of wheel 7 in the required direction, the crank 9 should be angled to the foot plate 3 at an angle Θ where Θ is less than 90°.

A restoration means 15 is also provided and includes a spring 16 coupled between one end 17 of a crank arm 18 which itself is secured to the base plate 5, and a fixed location 19 on the outward facing side of the wheel 7 on which the fixing end of the spring is rotatable to the wheel 7. The arrangement of the restoration means 15 is such that spring 16 biases the foot plate away from the base plate after a driving stroke and helps restore the crank 9 to a position where Θ is less than 90° for optimal rotational displacement upon subsequent pivotal movement of the foot plate towards the base plate. For this purpose, the axial direction of the spring preferably extends to the centre of wheel 7 when the device is in a rest state, and the crank arm is up in a position between a dead angle position in which the first member can't turn or move the crank

and a 12 o'clock position. The arrangement is also such that the restoration means assists the drive wheel in turning a full circle after a driving stroke of the foot. In use of the device, potential energy resulting from foot movement such as by lifting a heel 25 relative to a toe 26 during skating, can be converted into rotational energy of the wheel 7 upon lowering of the heel. Such rotational energy can be used to drive a wheel 27 of a skate 28 via a gear or freewheel assembly 30 which is mounted to engage the wheel 7 and drive axle 31 of wheel 27 . The engagement between the wheel 7 and gear 29 can be frictional or by virtue of intermeshing teeth formed on the wheel 7 and gear 30. The engagement of the gear or freewheel assembly is preferably such that rotational movement of the drive wheel is transmitted to wheel 27 only during rotation of the drive wheel 7 in a first direction (clockwise as viewed in the Figures ) so as to effect rotation of the skated wheel 27 in a second direction (anticlockwise as viewed in the Figures), and is such that the skate wheel 27 is free to rotate in the second direction.

Alternatively, the rotational energy of the wheel of the device 1 may be used to drive a generator 32 via a gear or a freewheel assembly 30 as shown in Figure 4. As a further alternative, the device 1 and the generator 32 may both be carried in a shoe or the like with the generator 32 being arranged in a heel of the shoe, whereby potential energy of a user's heel being lifted during walking movement is converted into rotational movement of the drive wheel, to thereby drive the generator, upon subsequent lowering of the heel.

The device, as shown in Figure 1 and 4, has a boot 50 formed integrally with the foot plate 3 but a user's foot can instead be secured to the device 1 by any suitable securing means or may simply rest on the plate 3 without the provision of such securing means.

It will also be appreciated that the specific arrangement of the above described restoration means need not be employed. For example, the restoration means may be in the form of a spring attached directly to the base plate at any suitable location. Alternatively the arrangement may be such as is shown in Figure 5.

The device as shown in Figure 5 functions similarly to the device of Figure 1 and like reference numerals are used to denote like parts. However, the device is modified in that the restoration means 15 is in the form of a spring extending from the base plate 5 to

a position on the crank 9 such that the downward stroke of the foot rotates the wheel 7 clockwise as shown and the restoration force of the spring causes the wheel 7 to rotate anticlockwise to its original position when the foot plate 3 and base plate 5 are moved apart from one another. A stopper 52 is also provided on the support 8 to prevent the crank 9 from rotating anticlockwise, as shown, past the position where Θ is equal to 90°..

In yet another alternative, the above-described device may form part of an exercise machine whereby the rotational motion of the drive wheel is used to drive an electric generator or the like forming part of the exercise machine. It will also be appreciated that many modifications and variations may be made to the above described device without departing from the spirit and scope of the invention as defined in the following claims.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word 'comprise', or variation such as 'comprises' or 'comprising', will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.