WO2021117025A1

WO2021117025A1 - A stilt

Info

Publication number: WO2021117025A1
Application number: PCT/IE2020/000007
Authority: WO
Inventors: Paul O'reilly; Michael Foy; Patrick Downey
Original assignee: Pmp Technologies Limited
Priority date: 2019-12-13
Filing date: 2020-12-11
Publication date: 2021-06-17

Abstract

A stilt (1) comprises a ground engaging element (3), a riser (5) extending upwardly from the ground engaging element (3) to a foot engaging element (7), The riser (5) comprises a first riser member (37) extending upwardly from the ground engaging element (3), and a second riser member (38) extending downwardly from the foot engaging element (7) into a bore (40) extending through the first riser member (37). The second riser member (38) is externally threaded with external screw threads (49) which engage an internal screw thread (47) within the bore (40) of the first riser member (37). An electrically powered drive motor (51 ) rigidly mounted in a housing (52) extending downwardly from the foot engaging element (7) rotates the second riser member (38) through a gear train (55) within the internally threaded bore (40) of the first riser member (37) for rising and lowering the foot engaging element (7) relative to the ground engaging element (3). Straps (9) are provided on the foot engaging element (7) for securing a foot of a person onto the foot engaging element (7). A carrier member (10) extending upwardly from the foot engaging element (7) carries a leg engaging strap (14) for securing the corresponding leg of a person to the carrier member (10).

Description

"A stilt"

The present invention relates to a stilt, and the invention also relates to a pair of stilts, for example, though not limited to industrial stilts which typically are used by tradesmen and tradeswomen wishing to extend their height when carrying out their trade, for example, when carrying out internal work in a building, such as painting and plastering a ceiling or an upper part of a wall of a building, or when carrying out external work, for example, painting, rendering, cleaning external parts of a building, for example, walls, gutters, eves and the like, However, the stilt and the pair of stilts according to the invention are not so limited. According to the invention there is provided a stilt comprising a ground engaging element, an elongated load bearing riser extending upwardly from the ground engaging element, a foot engaging element supported on the riser spaced apart above the ground engaging element, and a powered drive means for adjusting the spacing of the foot engaging element above the ground engaging element. In one embodiment of the invention the riser comprises a riser of adjustable length.

In another embodiment of the invention the riser comprises a first member and a second member, at least one of the first member and the second member comprising an elongated member, and one of the first and second members being moveable relative to the other one of the first and second members for adjusting the spacing of the foot engaging element above the ground engaging element.

In another embodiment of the invention both the first and the second members of the riser comprise elongated members. Preferably, one of the first and second members of the riser is located within the other one of the first and second members, and preferably, one of the first and second members of the riser is axially moveable relative to the other one of the first and second members.

In one embodiment of the invention one of the first and second members of the riser comprises a bore for receiving the other one of the first and second members, and preferably, the bore of the one of the first and second members of the riser comprises an internal screw thread along at least a part of the bore, and preferably, the internal screw thread extends the length of the bore. In another embodiment of the invention the other one of the first and second members of the riser comprises an external screw thread cooperable with the internal screw thread of the other one of the first and second members of the riser for urging the first and second members axially relative to each other on rotation of one of the first and second members relative to the other one of the first and second members, and preferably, the external screw thread extends along at least a portion of the one of the first and second members of the riser comprising the external screw thread thereon, and advantageously, the external screw thread extends along the length of the one of the first and second members of the riser comprising the external screw thread. In one embodiment of the invention each screw thread comprises a single start screw thread.

In one embodiment of the invention the first one of the first and second members of the riser comprises the internally threaded bore. In another embodiment of the invention the second one of the first and second members of the riser comprises the external screw thread.

Preferably, the second member of the riser extends into the internally threaded bore of the first member. Advantageously, the first member of the riser extends upwardly from the ground engaging element, and the second member of the riser extends downwardly from the foot engaging element. Advantageously, the second member of the riser is rotatably mounted on the foot engaging element.

Advantageously, the first member of the riser comprises a stationery member.

In another embodiment of the invention the drive means is configured to rotate one of the first and second members of the riser relative to the other one of the first and second members for urging one of the first and second members axially relative to the other one of the first and second members. In another embodiment of the invention the drive means is configured for rotating the second member of the riser, and advantageously, the drive means is mounted on the foot engaging element.

Preferably, a drive transmission means is provided for transmitting drive from the drive motor to the rotatably mounted one of the first and second members of the riser. Preferably, the drive transmission means comprises one of a gear train or a drive belt.

In one embodiment of the invention the drive means comprises a drive motor.

In another embodiment of the invention the drive means comprises an electrically powered drive motor, and preferably, the electrically powered drive motor is powered by a battery, and preferably, a rechargeable battery. In another embodiment of the invention the drive means is operated under the control of a control circuit, and preferably, the control circuit is remotely controlled, and preferably, is remotely controlled by a radio signal, which preferably, comprises a Bluetooth signal, Advantageously, the remote signal is transmitted from a remote control module, which preferably, is a portable remote control module. Advantageously, the remote control module is of pocket size.

In one embodiment of the invention an input interface is provided for inputting a control signal to the control circuit for controlling the operation of the drive means, and preferably, the input interface is carried on a mounting bracket extending upwardly from the foot engaging element. Preferably, the input interface is hardwired to the control circuit.

In another embodiment of the invention a foot securing means is provided for securing a foot of a subject to the foot engaging element, and in another embodiment of the invention a leg securing means is provided for securing the stilt to the leg of the subject. In another embodiment of the invention the leg securing means is carried on a carrier element extending upwardly from the foot engaging element.

In another embodiment of the invention the riser is pivotally coupled to the foot engaging element, and preferably, the foot engaging element extends between a toe portion and a heel portion. Preferably, the riser is pivotally coupled adjacent the heel portion about a pivot axis extending transversely relative to a centre line of the foot engaging element extending from the heel portion to the toe portion.

In another embodiment of the invention the riser is resiliently coupled to the ground engaging element for minimising pivotal movement of the riser relative to the ground engaging element. Advantageously, the resilient mounting extends from adjacent the toe portion of the foot engaging element to an anchorage on the riser above the transverse pivot axis about which the riser is pivotally coupled to the ground engaging element.

In another embodiment of the invention the toe portion of the ground engaging element is pivotally coupled to the heel portion thereof, and preferably, the toe portion of the ground engaging element is pivotally coupled to the heel portion thereof about a pivot axis extending transversely of the centre line extending from the heel portion to the toe portion.

Preferably, the pivotal connection of the toe portion to the heel portion of the ground engaging element is located closer to the toe portion than to the heel portion.

The invention also provides a pair of the stilts according to the invention, one of the stilts being configured for attaching to a left foot of a subject, and the other being configured for attaching to a right foot of the subject.

Preferably, the control circuits of the respective stilts are synchronised, and advantageously, the two stilts are controllable synchronously from the single remote control module. Preferably, each stilt is provided with an input interface for independent operation of the respective stilts.

The invention will be more clearly understood from the following description of an embodiment thereof, which is given by way of example only with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of a stilt according to the invention,

Fig. 2 is another perspective view of the stilt of Fig. 1,

Fig. 3 is a side elevational view of the stilt of Fig. 1

Fig. 4 is a front end elevational view of the stilt of Fig. 1 ,

Fig. 5 is a rear end elevational view of the stilt of Fig. 1, Fig. 6 is a top plan view of the stilt of Fig. 1 ,

Fig. 7 is an underneath plan view of the stilt of Fig. 1,

Fig. 8 is a cross-sectional side elevational view of the stilt of Fig. 1 on the line VIII-VIII of Fig.6,

Fig. 9 is a partly cut-away side elevational view of a portion of the stilt of Fig. 1 , and

Fig. 10 is a cross-sectional side elevational view of a stilt according to another embodiment of the invention.

Referring to the drawings, and initially to Figs. 1 to 9 thereof, there is illustrated a stilt according to the invention indicated generally by the reference numeral 1. The stilt 1 in this embodiment of the invention is suitable for a right foot of a subject. In practice, a pair of the stilts will be provided, one stilt being configured for fitting to the right foot of a subject, and the other being configured for fitting to the left foot of a subject. The only difference between the right hand and left hand stilts is the handing of the stilts. Accordingly, apart from the handing of the stilts, the right and left hand stilts are similar to each other, and accordingly, only the right hand stilt will be described.

The stilt 1 comprises a ground engaging element 3 which is provided by a ground engaging base 4 described in more detail below. A riser 5 extends upwardly from the ground engaging element 3 and supports a foot engaging element 7 for engaging and securing to the right foot of a subject. A foot securing means comprising a pair of straps 9, which terminate in buckles 8, are secured to the foot engaging element 7 for securing the right foot of a subject to the foot engaging element 7. A carrier member 10 extending upwardly from the foot engaging element 7 carries a leg engaging element 12. A leg securing means comprising a leg engaging strap 14, having a buckle 13 located thereon, is carried on the leg engaging element for securing the right leg of the subject to the stilt 1. Typically, around the calf of the leg of the subject.

Turning initially to the ground engaging base 4 of the ground engaging element 3, the ground engaging base 4 is of steel plate material, and extends from a heel end 15 to a toe end 16 and comprises a rearward base part 18 and a forward base part 19. The forward base part 19 is pivotally coupled to the rearward base part 18 about a forward pivot shaft 20 which extends transversely of a central line 22 of the ground engaging base part 4 extending centrally from the heel end 15 to the toe end 16. The forward pivot shaft 20 defines a forward pivot axis 24 extending transversely of the centre line 22 about which the forward base part 19 is pivotal relative to the rearward base part 18. In this embodiment of the invention the forward pivot shaft 20 is located towards the toe end 16 of the ground engaging base 4, and essentially the forward base part 19 defines a toe portion 25. The pivoting of the toe portion 25 relative to the rearward base part 18 permits rocking of the stilt 1 on the ground engaging base part 4.

Grip pads 27 of a suitable rubber or synthetic rubber material are provided on the underside of the ground engaging base 4 for providing grip of the ground engaging base part 4 on the floor or ground on which the person wearing the stilt is standing.

Turning now to the riser 5, the riser 5 extends upwardly from a mounting base block 29, which is pivotally coupled to the rearward base part 18 by a rearward pivot shaft 30, which in turn is carried on a pair of spaced apart mounting brackets 32 extending upwardly from the rearward base part 18, and which pivotally engages the mounting base block 29. The rearward pivot shaft 30 defines a transversely extending rearward pivot axis 34 which extends transversely relative to the centre line 22 for facilitating pivoting of the riser 5 forwardly and rearwardly relative to the ground engaging base as will be described below. A resilient anchorage 35 extending between the toe portion 25 and the mounting base block 29 resiliently retains the riser 5 extending substantially perpendicularly above and from the rearward base part 18 as will be described in more detail below.

The riser 5 comprises a first elongated riser member 37 extending upwardly from the mounting base block 29, and a second elongated riser member 38 extending downwardly from the foot engaging element 7. The first riser member 37 comprises an elongated tubular member having an elongated bore 40 extending therethrough from an upper end 42 of the first riser member 37 to a location 43 adjacent a lower end 44 of the first riser member 37, An end cap 45 closes the lower end 44 of the bore 40. In this embodiment of the invention the bore 40 is provided with an internal screw thread 47 extending the length of the bore 40. The second riser member 38 is provided with an external screw thread 49 which extends the length of the second riser member 38, and the second riser member 38 extends into the threaded bore 40 of the first riser member 37 with the external threads 49 of the second riser member 38 in threading engagement with the first riser member 37, so that by rotating the second riser member 38 in the bore 40 of the first riser member 37, the length of the riser 5 between the ground engaging base 4 and the foot engaging element 7 is adjustable for in turn adjusting the spacing of the foot engaging element 7 above the ground engaging element 3. In this embodiment of the invention the second riser member 38 is rotatably mounted in the foot engaging element 7 and supports the foot engaging element 7 on the riser 5.

An outer protective telescoping member 50 rigidly secured to the foot engaging element 7 extends downwardly from the foot engaging element 7 and slideably accommodates the first riser member 37 therein, so that as the second riser member 38 is rotated for raising and lowering the foot engagement element 7 relative to the ground engaging element 3, the outer telescoping member 50 slides upwardly and downwardly along the first riser 37. The telescoping member 50 is a relatively tight sliding fit on the first riser member 37 and as well as acting as a protective member also acts to strengthen and reinforce the riser 5 as the second riser member 38 is being raised and lower within the first riser member 37, and the telescoping member 50 also acts to guide the movement of the first and second riser members 37 and 38 as the second riser member moves upwardly and downwardly relative to the first riser member 37.

A drive means, in this embodiment of the invention an electrically powered drive motor 51 is rigidly mounted in a housing 52 extending downwardly from the foot engaging element 7. A drive shaft 54 of the motor 51 drives the second riser member 38 through a drive transmission means, in this embodiment of the invention a gear train 55 for rotating the second riser member 38 in the first riser member 37 for in turn rising and lowering the foot engaging element 7. In this embodiment of the invention the drive motor may comprise a stepper motor or any other suitable drive motor. The control of the drive motor is described below.

Turning now to the foot engaging element 7, the foot engaging element 7 comprises a platform 57 of moulded hard plastics material or any other suitable material. A mounting block 59 is rigidly mounted to the platform 57 of the foot engaging element 7 beneath the platform 57, and a suitable bearing (not shown) is located in the mounting block 59 for rotatably mounting the second riser member 38 in the upper mounting block 59. The housing 52 within which the drive motor 51 is mounted extends rigidly downwardly from the mounting block 59. The telescoping member 50 is also rigidly coupled to the mounting block 59 by a coupling housing 60. A casing 62 releasably secured to the platform 57 and to the outer telescoping member 50 encases the upper mounting block 59, the stepper motor 51 and the gear train 55. A heel engaging member 61 is adjustable mounted on the platform 57 of the foot engaging element 7 for adjusting the useable length of the platform 57 to accommodate the size of the foot of the subject.

Returning now to the resilient anchorage 35, the resilient anchorage 35 comprises a pair of telescoping members, namely, an inner telescoping member 64 which is slideable within an outer telescoping member 65. The inner telescoping member 64 is pivotally coupled to the mounting base block 29, while the outer telescoping member 65 is pivotally coupled to the toe portion 25. A compression spring 66 acting between a flange 67 on the inner telescoping member 64 and a flange 68 on the outer telescoping member 65 resiliently retains the riser 5 extending substantially perpendicularly relative to the rearward base part 18 of the ground engaging base 4. The inner telescoping member 64 is retaining within the outer telescoping member 65 by an engagement ring (not shown) located on the end of the inner telescoping member 64 within the outer telescoping member 65 which engages an inwardly directed flange adjacent an end 69 of the outer telescoping member 65, When the inner telescoping member 64 is fully extended from the outer telescoping member 65 and the rearward and forward base parts 18 and 19 are lying substantially in a common plane, the riser 5 extends substantially perpendicularly upwardly from the rearward base plate 18.

The action of the compression spring 66 between the flanges 67 and 68 urges the inner telescoping member 64 into its fully extending state from the outer telescoping member 65. However, the compression spring 66 permits limited movement of the inner telescoping member 64 into the outer telescoping member 65 to allow either the riser 5 to pivot about the rearward pivot axis 34 forwardly in the direction of the arrow A relative to the rearward base plate 18, or alternatively, permits the forward base part 19 of the ground engaging base 4 to pivot upwardly in the direction of the arrow B about the forward pivot axis 24 relative to the rearward base part 18. This permits ease of walking of a subject on the stilt 1.

Turning now to the carrier member 10 which carries the leg engaging element 12, the carrier member 10 is secured to and extends upwardly from the mounting block 59 of the foot engaging element 7. As well as the leg engaging element 12 being carried on the carrier member 10, an input interface, namely, a control panel 70 is also carried on the carrier member 10. The control panel comprises a battery compartment 72 within which a rechargeable battery (not shown) for powering the electric motor 51 is located. An on/off switch 73 selectively provides power to the control panel 70 and the motor 51 from the battery in the battery compartment 72. First and second button switches 74 and 75 are located in the control panel 70 for operating the motor 51 for in turn raising and lowering the foot engaging platform 7. The first button switch 74 operates the motor 51 for rising the foot engaging platform 7, while the second button switch 75 operates the motor 51 for lowering the foot engaging element 7. An indicator light 79 in the control panel 70 indicates that the control panel 70 has been activated by the switch 73, and a battery level indicator 80 indicates the status of the battery.

The control panel 70 also includes a radio receiver (not shown) configured to communicate with a pocket size remote control module 71. The radio receiver and the remote control module 71 are configured to communicate in a Bluetooth protocol. The remote control module 71 is configured to synchronously control the operation of the motors 51 in the right and left stilts so that the foot engaging elements 7 are raised and lowered synchronously with each other. The remote control module 71 is releasably secured to the carrier member 10 of one of the stilts 1, so that in use a person strapped onto the two stilts can if desired remove the remote control module 71 from the carrier member 10 and place the remote control module 71 in his or her pocket for easy access for raising and lowering the stilts. In this embodiment of the invention the stilt 1 also comprises an FM radio receiver (not shown) for receiving radio channels, which typically would be located within the casing 62. A speaker 85 is provided in the casing 62 through which music and speech from radio programmes received by the radio receiver is outputted. Volume and tuning controls (not shown) are provided for tuning the FM radio receiver to a desired radio channel. Typically, the volume and tuning controls would be located in an easily accessible location on the control panel 70, the casing 62 and/or on the remote control module 71. However, it will be appreciated that in other embodiments of the invention the FM radio receiver and the speaker may be omitted. It will also be appreciated that instead of or as well as a radio receiver suitable for receiving FM radio signals, the radio receiver may also receive signals on medium, long and short wave radio channels. However, while the stilts will be provided in pairs, one for the left hand foot, and one for the right hand foot, in general, it is envisaged that an FM radio receiver and the speaker 85 typically would be provided in one of the stilts only, although, in some cases, it is envisaged that the radio receiver and the speaker 85 may be provided in both stilts.

In use, a pair of the stilts, namely, a right stilt and a left stilt are secured to the respective feet of a subject, the right stilt being secured to the right foot of the subject and the left stilt being secured to the left foot of the subject. Initially the heel engaging members 61 are adjusted on the platforms 57 of the foot engaging elements 7 for adjusting the useable area of the platforms 57 to suit the size of the feet of the subject.

The straps 9 are then secured around the shoes of the subject for securing the shoes of the subject to the foot engaging elements 7. The leg engaging straps 14 of the stilt 1 are secured to the corresponding legs of the subject. With the stilts 1 so secured to the subject, the subject then stands on the stilts. In order to set the platforms 57 of the foot engaging elements 7 at the desired height above the ground engaging elements 3, if the stilts 1 are to be adjusted independently of each other, the appropriate one of the first and second switches 74 and 75 of the respective stilts is operated for in turn operating the drive motors 51 for in turn raising or lowering the foot engaging elements 7. Alternatively, if the stilts are to be synchronously adjusted the adjustment is carried out from the remote control module 71.

With the foot engaging elements 7 at the desired height above the ground engaging elements 7, the subject can then walk on the stilts, and as the subject walks, the risers 5 and the toe portions 25 pivot relative to the rearward base parts 18 of the ground engaging elements 3 for facilitating walking of the subject. In general, further raising and lowering of the foot engaging elements 7 is carried out by the remote control module 71. Referring now to Fig. 10, there is illustrated a stilt according to another embodiment of the invention indicated generally by the reference numeral 90. The stilt 90 is substantially similar to the stilt 1 , and similar components are identified by the same reference numerals. In this embodiment of the invention the stilt 90 comprises a light 92, for example, an LED light to illuminate the area, and in particular, the ground along which a person wearing each stilt 90 of a pair of the stilts 90 may be walking, so that the person to which the stilts 90 are secured will be able to see where that person is walking, in the event that the area in which the person is working is dark. The light 92 is secured beneath the foot engaging element 70, and extends forwardly from the foot engaging element 7 in a generally forwardly downwardly direction for illuminating the path being followed by the person wearing the stilts 90, It is also envisaged that a light similar to the light 92 may be provided to the rear of the foot engaging element which would also be directed in a generally downwardly but rearwardly direction in order to light the area to the rear of the person wearing the stilt. Indeed, it is envisaged that in some embodiments of the invention lights similar to the light 92 may be located to one or both sides of the stilt, which would also be mounted beneath the foot engaging element 7 and would be directed outwardly downwardly for lighting the area to the sides of the stilt. Further, it is envisaged that a light or lights similar to the light 92 may be mounted on the control panel 70 and would be directed in a generally upwardly or a generally upwardly outwardly, rearwardly or forwardly direction for illuminating the area in a building in which the person wearing the stilt would be working. It is envisaged that such light or lights on the control panel 70 may be adjustable so that the direction of the beam from the light would be adjustable to illuminate the area on which the person wearing the stilt would be working.

While the riser of the stilt has been described as comprising a pair of elongated elements, one located within the other, and one internally threaded and the other externally threaded, while this is desirable in some embodiments of the invention, in other embodiments of the invention, other suitable risers may be used. For example, it is envisaged that the riser may comprise a pair of slideable telescoping members which could be operated pneumatically or hydraulically, and in some cases by an air spring. It is also envisaged that when one of the riser members is threadingly engageable with the other one of the riser members, the externally threaded riser member may be mounted on the ground engaging element, while the internally threaded riser member would be mounted on the foot engaging element. It is also envisaged that in some embodiments of the invention one of the riser members may comprise an internally threaded nut, which would be secured to the foot engaging element for raising and lowering the foot engaging element on an externally threaded elongated rod extending upwardly from the ground engaging element. Alternatively, the internally threaded nut could be provided on a mounting member extending upwardly from the ground engaging element, and would threadingly engage an elongated externally threaded rod extending downwardly from the foot engaging element. It is also envisaged that instead of rotating the externally threaded element, the internally threaded element could be rotated, and the externally threaded element would be stationary. Additionally, while both of the riser members have been described as being threaded along their entire length, it is envisaged that in some cases only a portion of one of the riser members may be threaded, while the other one of the riser members would be threaded over its entire length. The riser member which would be threaded over only a portion of its length would be threaded along a sufficient length to carry the relevant weight required to be carried by it between the foot engaging element and the ground engaging element, and it is envisaged that the threaded portion may extend over a length of approximately 50% to 70% of the length of the riser member threaded over its entire length.

While the stilt has been described as comprising the riser pivotally connected to the ground engaging element, while this is desirable it is not essential, and in certain cases, it is envisaged that the riser may be rigidly secured to the ground engaging element. It is also envisaged that in some embodiments of the invention the riser may be rigidly secured to the ground engaging element but the ground engaging element would be provided with a toe portion pivotally coupled to a rearward part of the ground engaging element, and the toe portion would be resiliently anchored to the riser extending rigidly upwardly from the ground engaging element. While the drive motor has been described as comprising a stepper motor or other suitable motor, any other drive means may be provided. It will also be appreciated that any other suitable drive transmission means besides a gear train may be provided for transmitting drive from the drive motor to the second riser member, for example, the drive transmission means may comprise a pulley drive transmission.

While the stilt has been described as comprising a single riser, it is envisaged in some embodiments of the invention that the riser may be provided with two, or even three risers. In general, it is envisaged that where more than one riser is provided, either all of the risers may be provided with inner and outer riser members 37 and 38 with internal and external screw threads, or alternatively, only one of the risers would be provided with inner and outer riser elements provided with external and internal screw threads, and the other risers while they would be provided with inner and outer telescoping members, they may be provided without inner and outer riser members with external and internal screw threads. In such cases, those risers which are provided with only inner and outer telescoping members, would be provided as guide elements for guiding the foot engaging element upwardly and downwardly relative to the ground engaging element.

While the various components of the stilt have been described as being of specific materials, any suitable materials may be used.

It is also envisaged that the stilts according to the invention may be provided with a GPS tracking system, in order to allow tracking of the stilts, in the event of them being lost or stolen.

The invention is not limited to the embodiment hereinbefore described which may be varied in construction and detail.

Claims

1. A stilt comprising a ground engaging element, an elongated load bearing riser extending upwardly from the ground engaging element, a foot engaging element supported on the riser spaced apart above the ground engaging element, and a powered drive means for adjusting the spacing of the foot engaging element above the ground engaging element.

2. A stilt as claimed in Claim 1 in which the riser comprises a riser of adjustable length.

3. A stilt as claimed in Claim 1 or 2 in which the riser comprises a first member and a second member, at least one of the first member and the second member comprising an elongated member, and one of the first and second members being moveable relative to the other one of the first and second members for adjusting the spacing of the foot engaging element above the ground engaging element.

4. A stilt as claimed in Claim 3 in which both the first and the second members of the riser comprise elongated members.

5. A stilt as claimed in Claim 3 or 4 in which one of the first and second members of the riser is located within the other one of the first and second members thereof.

6, A stilt as claimed in any of Claims 3 to 5 in which one of the first and second members of the riser is axially moveable relative to the other one of the first and second members.

7. A stilt as claimed in any of Claims 3 to 6 in which one of the first and second members of the riser comprises a bore for receiving the other one of the first and second members.

8. A stilt as claimed in Claim 7 in which the bore of the one of the first and second members of the riser comprises an internal screw thread along at least a part of the bore.

9. A stilt as claimed in Claim 8 in which the internal screw thread extends the length of the bore.

10. A stilt as claimed in any of Claims 7 to 9 in which the other one of the first and second members of the riser comprises an external screw thread cooperable with the internal screw thread of the other one of the first and second members of the riser for urging the first and second members axially relative to each other on rotation of one of the first and second members relative to the other one of the first and second members.

11. A stilt as claimed in Claim 10 in which the external screw thread extends along at least a portion of the one of the first and second members of the riser comprising the external screw thread thereon.

12. A stilt as claimed in Claim 10 or 11 in which the external screw thread extends along the length of the one of the first and second members of the riser comprising the external screw thread.

13. A stilt as claimed in any of Claims 8 to 12 in which each screw thread comprises a single start screw thread.

14. A stilt as claimed in any of Claims 8 to 13 in which the first one of the first and second members of the riser comprises the internally threaded bore.

15. A stilt as claimed in any of Claims 8 to 14 in which the second one of the first and second members of the riser comprises the external screw thread.

16. A stilt as claimed in any of Claims 7 to 15 in which the second member of the riser extends into the internally threaded bore of the first member,

17. A stilt as claimed in any of Claims 3 to 16 in which the first member of the riser extends upwardly from the ground engaging element, and the second member of the riser extends downwardly from the foot engaging element.

18. A stilt as claimed in any of Claims 3 to 17 in which the second member of the riser is rotatably mounted on the foot engaging element.

19. A stilt as claimed in any of Claims 3 to 18 in which the first member of the riser comprises a stationery member.

20. A stilt as claimed in any of Claims 3 to 19 in which the drive means is configured to rotate one of the first and second members of the riser relative to the other one of the first and second members for urging one of the first and second members axially relative to the other one of the first and second members.

21. A stilt as claimed in any of Claims 3 to 20 in which the drive means is configured for rotating the second member of the riser.

22. A stilt as claimed in any of Claims 3 to 21 in which the drive means is mounted on the foot engaging element.

23. A stilt as claimed in any of Claims 3 to 22 in which a drive transmission means is provided for transmitting drive from the drive motor to the rotatably mounted one of the first and second members of the riser.

24, A stilt as claimed in Claim 23 in which the drive transmission means comprises one of a gear train or a drive belt.

25. A stilt as claimed in any preceding claim in which the drive means comprises a drive motor.

26. A stilt as claimed in any preceding claim in which the drive means comprises an electrically powered drive motor.

27. A stilt as claimed in Claim 26 in which the electrically powered drive motor is powered by a battery.

28. A stilt as claimed in Claim 26 or 27 in which the electrically powered drive motor is powered by a rechargeable battery.

29. A stilt as claimed in any preceding claim in which the drive means is operated under the control of a control circuit.

30. A stilt as claimed in Claim 29 in which the control circuit is remotely controlled.

31. A stilt as claimed in Claim 29 or 30 in which the control circuit is remotely controlled by a radio signal.

32. A stilt as claimed in any of Claim 29 to 31 in which the control circuit is remotely controlled by a Bluetooth signal,

33. A stilt as claimed in any of Claims 29 to 32 in which the control circuit is controlled by a remote signal transmitted from a remote control module.

34. A stilt as claimed in Claim 33 in which the remote control module comprises a portable remote control module.

35. A stilt as claimed in Claim 34 in which the portable remote control module comprises a pocket sized remote control module.

36. A stilt as claimed in any of Claims 29 to 35 in which an input interface is provided for inputting a control signal to the control circuit for controlling the operation of the drive means.

37. A stilt as claimed in Claim 36 in which the input interface is carried on a mounting bracket extending upwardly from the foot engaging element.

38. A stilt as claimed in Claim 36 or 37 in which the input interface is hardwired to the control circuit.

39. A stilt as claimed in any of Claims 36 to 38 in which the remote control module is configured to communicate with the input interface

40. A stilt as claimed in any preceding claim in which a foot securing means is provided for securing a foot of a subject to the foot engaging element.

41. A stilt as claimed in any preceding claim in which a leg securing means is provided for securing the stilt to the leg of the subject.

42. A stilt as claimed in Claim 41 in which the leg securing means is carried on a carrier element extending upwardly from the foot engaging element.

43. A stilt as claimed in any preceding claim in which the riser is pivotally coupled to the foot engaging element.

44. A stilt as claimed in any preceding claim in which the foot engaging element extends between a toe portion and a heel portion.

45. A stilt as claimed in any preceding claim in which the riser is pivotally coupled adjacent the heel portion about a pivot axis extending transversely reiative to a centre line of the foot engaging element extending from the heel portion to the toe portion.

46. A stilt as claimed in any preceding claim in which the riser is resiliently coupled to the ground engaging element for minimising pivotal movement of the riser relative to the ground engaging element.

47. A stilt as claimed in Claim 46 in which the resilient mounting extends from adjacent the toe portion of the foot engaging element to an anchorage on the riser above the transverse pivot axis about which the riser is pivotally coupled to the ground engaging element.

48. A stilt as claimed in any preceding claim in which the toe portion of the ground engaging element is pivotally coupled to the heel portion thereof.

49. A stilt as claimed in any preceding claim in which the toe portion of the ground engaging element is pivotally coupled to the heel portion thereof about a pivot axis extending transversely of the centre line extending from the heel portion to the toe portion.

50. A stilt as claimed in Claim 48 or 49 in which the pivotal connection of the toe portion to the heel portion of the ground engaging element is located closer to the toe portion than to the heel portion.

51. A pair of stilts, each stilt of the pair thereof comprising a stilt as claimed in any preceding claim, one of the stilts being configured for attaching to a left foot of a subject, and the other being configured for attaching to a right foot of the subject.

52. A pair of stilts as claimed in Claim 51 in which the control circuits of the respective stilts are synchronised,

53. A pair of stilts as claimed in Claim 51 or 52 in which the two stilts are controllable synchronously from the single remote control module.

54. A pair of stilts as claimed in any of Claims 51 to 53 in which each stilt is provided with an input interface for independent operation of the respective stilts.