WO2002059499A2

WO2002059499A2 - Improvements to telescopic props

Info

Publication number: WO2002059499A2
Application number: PCT/GB2002/000327
Authority: WO
Inventors: Barry Levison
Original assignee: Neumann, Benny, William
Priority date: 2001-01-24
Filing date: 2002-01-24
Publication date: 2002-08-01
Also published as: WO2002059499A3; GB0101826D0; GB2371484A; GB2371485A; GB0201591D0

Abstract

The present invention provides an adjustable prop/extensor, which comprises a telescopic member having two or more telescoping sections (3, 4), the prop/extensor further comprising a piston (5) and cylinder means, the cylinder means (3) containing a first pressure fluid, the piston means (5) being associated with one of the telescopic sections (4) and the cylinder means being associated with the other (3) whereby the first pressure fluid acts as a spring between the telescopic sections, the cylinder means being selectively in fluid communication with a reservoir means (14) for storing a second pressure fluid that is less compressible than said first pressure fluid.

Description

IMPROVEMENTS TO TELESCOPIC PROPS

Field of the Invention

The present invention concerns improvements in and relating to telescopic props and extensors which may be as used in a wide range of different technical applications including supports for vehicles such as telescopic suspensions of aircraft undercarriages and specifically further including walking sticks and the like props/supportive aids for assisting an individual to rise to or lower from a standing position and/or to walk or ski and is intended to encompass not simply canes and crutches, but also frames such as Zimmer frames or other such aids, as well as ski poles for ski-ing. Background to the Invention

Aids for rising and walking that lack some means for adjusting their length and which lack means for cushioning the user from the forces of the ground impact of the leg(s) of the aid are impractical for most users and over recent years there has been growth in the number of proposed designs of walking sticks/crutches/frames which incorporate such length adjusting means and/or cushioning means. For example, a shock-absorbing walking stick having an elastic tubular element for cushioning is described in US 6, 131 , 592. A stick to help a user to sit and to rise and which incorporates a shock absorber having a spring-loaded piston is described in JP 11309007A. A collapsible crutch that is pumped up by a motorised pneumatic pump is described in AU 199664474.

Most modern crutches are length-adjustable and comprise legs of telescopic tubular sections but adjustment is generally basic, using simple catches to lock the leg at a chosen length. This adjustment must be done manually while the crutch is not in use. A length-adjustable crutch having telescopic tubular sections with a piston inter-connecting them and which is thereby pneumatically or hydraulically length adjusted is disclosed in GB 2, 012,591 A . Length adjustment is achieved by opening a valve in a conduit linking opposing chambers on either side of the piston to allow ducting of compressed pneumatic, hydro-pneumatic or hydraulic fluid from one side of the piston to the other. This arrangement is designed to make it substantially easier for the user to adjust the length of the crutches, even while using them, but it is not only relatively complex in construction and therefore costly and weighty but also has no means for independently adjusting the cushioning spring tension provided by the compressed pneumatic/hydraulic fluid.

It is one general objective of the present invention to provide an improved adjustable walking stick that addresses these problems of the prior art.

It is a broader general objective of the present invention to provide an improved adjustable prop/extensor that can be used in a wide range of technologies/technical applications including not only suspension systems but also, for example, robotic arms/extensors that may have a gripper or other tool/effector mounted to one end of the extensor.

Summary of the Invention According to a first aspect of the present invention there is provided an adjustable prop/extensor, which comprises a telescopic member having two or more telescoping sections, the prop/extensor further comprising a piston and cylinder means, the cylinder means containing a first pressure fluid, the piston means being associated with one of the telescopic sections and the cylinder means being associated with the other whereby the first pressure fluid acts as a spring between the telescopic sections, the cylinder means being selectively in fluid communication with a reservoir means for storing a second pressure fluid that is less compressible than said first pressure fluid.

Preferably the first pressure fluid is air and the second pressure fluid is a liquid. Advantageously the cylinder means is in selective fluid communication with atmosphere to vent or replenish air in the cylinder means.

Suitably the means for placing the cylinder in fluid communication with the reservoir also places the cylinder in fluid communication with atmosphere.

Preferably the reservoir has an air vent to allow free passage of air between the reservoir and atmosphere but not of the liquid second pressure fluid.

Advantageously the air vent comprises a semi permeable membrane.

Preferably the air vent is so shaped and positioned and the reservoir is only partially filled with a liquid second pressure fluid at its maximum operational level of fill so that the vent remains at all times substantially clear of the level of the liquid second pressure fluid irrespective of the orientation of the member.

Suitably the reservoir has a capacity that is at least equal to and preferably substantially greater than the volume of second pressure fluid.

Advantageously the means for placing the cylinder in fluid communication with the reservoir comprises a valve mounted in a channel between the cylinder and the reservoir, which valve is resiliently biased to a closed position and moveable to an open position by a manually operable actuating means.

Preferably the prop is a crutch, walking stick or the like supportive aid and having a handle means at the upper in use end thereof.

Suitably the reservoir for the second pressure fluid is formed in the handle means.

According to a further aspect of the present invention there is provided an adjustable walking stick, crutch or the like prop/supportive aid, which comprises a telescopic leg having two or more telescoping sections and a handle means at its upper in use end, the walking stick or the like further comprising a piston and cylinder means, the cylinder means containing a first pressure fluid, the piston means being associated with one of the telescopic sections and the cylinder means being associated with the other whereby the first pressure fluid acts as a spring between the telescopic sections, the cylinder means being selectively in fluid communication with a reservoir means for storing a second pressure fluid that is less compressible than said first pressure fluid.

According to a first aspect of the present invention there is provided an adjustable prop/extensor, which comprises a telescopic member having two or more telescoping sections, the prop/extensor further comprising a piston and cylinder means, the cylinder means containing a first pressure fluid, the piston means being associated with one of the telescopic sections and the cylinder means being associated with the other whereby the first pressure fluid acts as a spring between the telescopic sections, the cylinder means being selectively in fluid communication with a reservoir means for storing the first pressure fluid in a pressure-tight manner whereby the first pressure fluid may be accumulated in the reservoir means from the cylinder and selectively released back to the cylinder when required. This accumulated pressurised fluid when selectively released back into the cylinder may be used to force the piston bearing telescopic section away from the cylinder bearing section. In the context of a telescopic walking stick or prop this would give a selectively operated boost to, for example, enable a seated person to selectively propel him/herself upwardly to a standing position. This mechanism may, of course, have numerous further uses in telescopic props and extensors. Suitably the fluid is air and the piston has a non-return valve to allow air to be drawn into the cylinder. Preferably the adjustable prop/extensor's reservoir has a first non-return valve to allow air to pass from the cylinder into the reservoir.

Advantageously, where the device is a prop, the piston-bearing telescopic section is positioned toward the lower, in use, end of the prop and the reservoir is positioned toward the upper in use end of the prop above the cylinder.

Brief Description of the Drawings

A preferred embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, wherein:

Figure 1 is a side elevation view of a walking stick embodying the invention;

Figure 2 is a schematic sectional view of the upper part of the walking stick;

Figure 3 is a sectional view of the shaft of the walking stick - in the insets to the right of Figure 3 the respective upper and lower end stoppers and piston head are illustrated in section from an elevation perpendicular to Figure 3;

Figure 4 is a set of diagrams illustrating an alternative suitable shape of handle for the walking stick firstly as viewed from the side and then sectional views of that handle along the lines A and B in the side view; and

Figure 5 is a schematic longitudinal sectional view of an alternative telescoping walking stick having a "gas spring" and mechanism for providing adjustability of the gas spring.

Description of the Preferred Embodiment

Referring to the illustrations, the walking stick comprises a leg/shaft 2 that is formed of upper and lower telescoping sections 3, 4, the upper section 3, at least, being tubular and having an internal bore so that the lower section 4 may telescopically slide therewithin (see Figure 3). The lower telescoping section 4 need not be tubular but this is preferred for lightness of construction.

At its upper end the walking stick has a handle fitment 1 that, as can be seen from Figure 2, is a hollow item serving as a reservoir 14 for fluid. This handle 1 is suitably a rigid plastics moulding and is preferably detachable from the shaft 2 to facilitate any necessary maintenance.

As can be seen from Figure 3, the lower telescopic section 4 of the shaft 2, despite being tubular, is plugged at each end by stoppers 5, 6. The lower stopper 6 is fixed in place by a pin 20. This has a terminal socket 21 which is suitably adapted to receive any of a variety of terminal attachments such as a rubber knob, spike or stud.

The upper stopper 5 at the upper, in use, end of the lower telescopic section 4 functions as a piston head in use and will hereinafter be referred to as piston head 5. It too is secured to the tubular section 4 by a pin 20. This piston head 5 and the lower tubular section 4 are a close sliding fit within the upper tubular section 3 of the shaft 2 and the piston head 5 is formed with an annular channel 13 around its circumference that accommodates an O ring 18 rendering the piston head 5 a gas tight fit within the upper tubular section 3 of the shaft 2.

The upper, in use, end of the upper telescopic section 3 of the shaft 2 is plugged by a channelled stopper 7. This channel stopper 7 is, again, secured in place by a pin 20. It too has an annular groove 13 around its circumference accommodating an O ring 18. Unlike the stoppers 5, 6 of the lower telescopic section 4, however, the channelled stopper 7 of the upper section 3 has a channel 8 extending longitudinally and centrally therethrough and which is occluded by a valve element 10 that is displaceable for opening of the channel 8 by movement of an actuating pin 12 in the handle 1. The valve 10 is normally closed - suitably being a spring loaded valve such as a schroeder valve - and serves to form an air tight seal so that the pressure fluid chamber 30 defined within the upper telescopic section 3 between the piston head 5 and the channelled stopper 7 is capable of holding fluids therewithin, such as air, under substantial compression. The upper tubular telescopic section 3 of the shaft 1 functions as a piston cylinder in which the lower section 4 with its piston head 5 slides as a piston.

In assembling the walking stick, the piston head 5 end of the lower telescopic section 4 of the shaft 2 is simply inserted into the tubular upper telescopic section 3. With the valve 10 in its normal closed position, the piston head 5 of the lower telescopic section 4 will move up the upper telescopic section 3 against the resistance of the air column retained in the upper section 3, moving only as far as the applied force compressing the air column in the chamber 30 will allow. If the actuating pin 12 is operated by its push button head 11 to thereby open the valve 10, the air within the upper telescopic section 3 will be able to escape through the channel 8 - thereby allowing the lower telescopic section 4 to be fully collapsed into the upper telescopic section 3.

Air passing from the upper telescopic section 3 into the reservoir 14 suitably vents through a venting aperture 25 in the handle 1. This venting aperture 25 is adapted to allow free passage of air but is suitably a barrier to passage of liquid for reasons as will become apparent shortly.

Whereas progressive collapse of the lower telescopic section 4 into the upper section 3 is enabled/facilitated whilst the valve 10 is held open, the valve 10 may be closed at any selected stage of relative telescopic movement of the upper 3 and lower 4 shaft sections, enabling the length of the air column within the chamber 30 of the upper telescopic section 3 to be selected by the user closing the valve 10. The air column that remains within the chamber 30 of the cyclinder acts as an air spring which will not only cushion the user against any jarring impacts of the walking stick with the ground but also may be used to assist in propelling the user upwardly and/or forwardly by the energy stored in the compressed air spring.

The spring tension/energy stored in the gas (air) spring can be adjusted by varying the length of the retained air column within the chamber 30 of the cylinder defined by the upper telescopic section 3.

The hollow handle 1 of the walking stick stores a volume of liquid such as water within the reservoir 14 of the handle 1. This liquid sits over the entrance to the channel when the walking stick is in its normal upright orientation and may drain into the cylinder via the channel 8 when the valve 10 is moved from its closed position to its open position by the actuating pin 12. The water or other liquid is relatively incompressible in comparison to the air in the air column and reduces the length of the air column, thereby increasing the compression of the air column.

The capacity of the reservoir 14 is suitably at least equal to the maximum volume of liquid that is intended to be introduced into the upper section 3 of the shaft 2 and is preferably substantially larger than this. When fully collapsed, the liquid content of the chamber 30 of the shaft 1 upper tubular section 3 is pumped by the piston head 5 back into the reservoir 14 of the hollow handle 1. Conversely, when the walking stick shaft 2 is fully extended, the liquid is substantially completely transferred into the chamber 30 of the shaft upper tubular section 3. At any intermediate stage between these two extreme positions the extent of transfer of the liquid is directly proportional so that, for example, at half way extension half of the liquid in the reservoir 14 of the handle 1 will have been transferred to the chamber 30 of the shaft 2. This ensures that the "spring tension" of the air column in the chamber 30 remains approximately uniform irrespective of the length of extension of the shaft 2 that is set by the user. This general configuration of the walking stick to operate with the transfer of the liquid proportional to extension giving uniform spring tension provides a first generally usable mode of operation.

However, the user (or possibly the supplier of the walking stick) needs also to have the facility to adjust the spring tension independently of the extent of extension of the walking stick shaft 2. This may be done straightforwardly by the user tilting the walking stick to allow some air, rather than just the water, to enter the chamber 30.

By varying the proportion of liquid relative to air transferred from the reservoir

14 to the chamber 30 and by limiting the maximum extended length of the shaft 2 of the walking stick it is possible to tailor the walking stick to the precise needs of the user. For example, the walking stick may be adapted for use by a tall relatively light individual, a tall heavy individual, a short light individual or a short heavy individual. In contrast to a conventional walking stick, the walking stick of the present invention is extremely versatile and useful. It can be precision set to the needs of the user and adjusted between a wide range of different lengths and spring tensions. The resilient lengthening or shortening movements of the shaft 1 serve to automatically adjust the effective length of the walking stick in use. This feature saves the user from having to vary their arm position throughout a given stroking movement of the walking stick - since normal use of a walking stick involves movement of the walking stick in an arcuate motion with the stick free end being at its farthest extent when at its forward most position.

The walking stick may be extended or collapsed for easy transport and storage and its long travel spring action eliminates jarring. The gas spring mechanism of the walking stick has a fail-safe configuration in which the valve release will not be accidentally activated by the stored pressure. In further contrast to conventional walking sticks, there is no need for locking pins or clamps. Turning to Figure 5 of the accompanying drawings, this illustrates an alternative or supplementary design of gas spring mechanism that may be used in the walking stick. As will be seen, the walking stick shaft 100 has an upper handle end 101 and a lower end/tip 102, the shaft 100 being telescopic and having an upper telescopic section 103 and a lower telescopic section 104 with the lower section 104 telescopically sliding within the upper section 103.

The lower section 104 has an upper end stopper 105 and a lower end stopper 106.

The upper telescopic section 103 has an upper end stopper 107 and an intermediate stopper 108.

Between each adjacent stopper the tubular walking stick shaft 100 defines a respective chamber - lower air chamber 109 between the upper 105 and lower 106 end stoppers of the lower telescopic section 104, and an intermediate air chamber 110 between the upper end stopper 105 of the lower telescopic section 104 and the intermediate stopper 108 of the upper telescopic section 103, and finally an upper air chamber 111 between the intermediate stopper 108 and the upper stopper 107 of the upper telescopic section 103.

The lower chamber 109 is in direct gas communication with atmosphere via an inlet/vent 122. The intermediate chamber 110 may be placed into gas communication with the lower chamber 109 via a channel 121 through the upper end stopper 105 of the lower telescopic section 104 subject to displacement of a gravity valve 119 that blocks the upper end of the channel 121.

The intermediate chamber 110 is, in turn, selectively in gas communication with the upper chamber 111 by either of a pair of channels through the intermediate stopper 108. A first of these channels 114 is provided with a valve that seats in the lower face of the intermediate stopper 108 and which may be actuated by an actuating pin 112 that is shown as being mounted in the upper end stopper 107 and extending down through the upper chamber 111 to contact the valve 13.

The actuating pin 112 is spring loaded by resilient biasing means 116 and when pushed against the resistance of the spring 1 16 will displace the valve 113 to open the channel 114.

The second channel and associated valve 115 in the intermediate stopper 108 seats against the upper face of the intermediate stopper 108 and, therefore, opens in the opposite direction to the actuator pin 112 actuated valve 113.

The operation of this gas spring mechanism will now be described. Firstly, when charging the gas spring, the objective is to fill the upper chamber 111 with highly compressed air, compressed to a level to give the desired degree of resilience and suitably to a level which provides a powerful uplift to assist the user in lifting or lowering him/herself.

The upper chamber 111 is charged with pressurised air by repeated upward and downward pumping movement of the upper telescopic section 103 relative to the lower section 104. This reciprocating motion in its upstroke draws air in through the air inlet 122 in the lower tubular section 104. This air will be sucked upwardly through the channel 121 in the upper end stopper 105 of the lower telescopic section 104, passing the gravity valve 119 and entering the intermediate chamber 110. In the downstroke as the upper telescopic section 103 is pushed down over the lower section 104 the gravity valve 119 will be shut preventing exhaust of the air from the intermediate chamber 110 back down through the channel 121. Instead, the compressed air in the intermediate chamber 110 will unseat the valve 115 in the intermediate stopper 108 so that the air in the intermediate chamber 110 will pass up into the upper chamber 111. The next upstroke of the upper telescopic section 103 will draw yet further air into the intermediate chamber 110 and which on the next downstroke will be forced again into the upper chamber 111. In this way the upper chamber 111 becomes increasingly pressurised and will store a substantial amount of gas spring energy which may be passed back into the intermediate chamber 110 by depressing the actuating pin 112. The reintroduction of the compressed air into the intermediate chamber 110 allows the gas spring to expand pushing the upper telescopic section 103 upwardly relative to the lower telescopic section 104.

Although in the above description of the preferred embodiment of the invention the telescopic adjustable prop is a walking stick, the present invention also encompasses in its broadest aspect not only props for humans and for machines but also telescopically extendible devices (extensors) irrespective of function.

Claims

CLAIMS 1. An adjustable prop/extensor, which comprises a telescopic member having two or more telescoping sections, the prop/extensor further comprising a piston and cylinder means, the cylinder means containing a first pressure fluid, the piston means being associated with one of the telescopic sections and the cylinder means being associated with the other whereby the first pressure fluid acts as a spring between the telescopic sections, the cylinder means being selectively in fluid communication with a reservoir means for storing a second pressure fluid that is less compressible than said first pressure fluid.

2. An adjustable prop/extensor as claimed in claim 1 , wherein the first pressure fluid is air and the second pressure fluid is a liquid.

3. An adjustable prop/extensor as claimed in claim 2 wherein the cylinder means is in selective fluid communication with atmosphere to vent or replenish air in the cylinder means.

4, An adjustable prop/extensor as claimed in claim 3, wherein the means for placing the cylinder in fluid communication with the reservoir also places the cylinder in fluid communication with atmosphere.

5. A prop/extensor as claimed in claim 4, wherein the reservoir has an air vent to allow free passage of air between the reservoir and atmosphere but not of the liquid second pressure fluid.

6. A prop/extensor as claimed in claim 5, wherein the air vent comprises a semi permeable membrane.

7. A prop/extensor as claimed in claim 5 or claim 6 wherein the air vent is so shaped and positioned and the reservoir is only partially filled with a liquid second pressure fluid at its maximum operational level of fill so that the vent remains at all times substantially clear of the level of the liquid second pressure fluid irrespective of the orientation of the walking sticks or the like.

8. A prop/extensor as claimed in any preceding claim, wherein the reservoir has a capacity that is at least equal to and preferably substantially greater than the volume of second pressure fluid.

9. A prop/extensor as claimed in any preceding claim, wherein the means for placing the cylinder in fluid communication with the reservoir comprises a valve mounted in a channel between the cylinder and the reservoir, which valve is resiliently biased to a closed position and moveable to an open position by a manually operable actuating means.

10. A prop/extensor as claimed in claim 9, the prop being a crutch, walking stick or the like supportive aid and having a handle means at the upper in use end thereof.

11. A prop/extensor as claimed in claim 10 wherein the reservoir for the second pressure fluid is formed in the handle means.

12. An adjustable walking stick or the like prop/supportive aid, which comprises a telescopic leg having two or more telescoping sections and a handle means at its upper in use end, the walking stick or the like further comprising a piston and cylinder means, the cylinder means containing a first pressure fluid, the piston means being associated with one of the telescopic sections and the cylinder means being associated with the other whereby the first pressure fluid acts as a spring between the telescopic sections, the cylinder means being selectively in fluid communication with a reservoir means for storing a second pressure fluid that is less compressible than said first pressure fluid.

13. An adjustable prop/extensor, which comprises a telescopic member having two or more telescoping sections, the prop/extensor further comprising a piston and cylinder means, the cylinder means containing a first pressure fluid, the piston means being associated with one of the telescopic sections and the cylinder means being associated with the other whereby the first pressure fluid acts as a spring between the telescopic sections, the cylinder means being selectively in fluid communication with a reservoir means for storing the first pressure fluid in a pressure-tight manner whereby the first pressure fluid may be accumulated in the reservoir means from the cylinder and selectively released back to the cylinder when required.

14. An adjustable prop/extensor as claimed in claim 13, wherein the fluid is air and the piston has a non-return valve to allow air to be drawn into the cylinder.

15. An adjustable prop/extensor as claimed in claim 13 or claim 14, wherein the reservoir has a first non-return valve to allow air to pass from the cylinder into the reservoir.

16. An adjustable prop as claimed in claim 13, 14 or 15 wherein the piston-bearing telescopic section is positioned toward the lower, in use, end of the prop and the reservoir is positioned toward the upper in use end of the prop above the cylinder.