CRUTCH, WALKING STICK AND THE LIKE WITH STEPLESSLY VARIABLE LENGTH

Abstract: A crutch, walking stick or the like with steplessly adjustable length, and comprising an outer tube (1) with at least one inner tube (2) which can be displaced outwards and inwards telescopically by means of a gas spring in the lower end. To counteract resilience during the use of the crutch as a consequence of a gas compressibility, the inner tube (2) is divided into two chambers (25, 26) with a sliding piston (8) and filled with a liquid. The piston (8) is influenced by a gas spring (10) disposed in the bottom of the inner tube (2). The piston (8) is secured to a hollow piston rod (3) in which there is disposed a valve spindle (17). The end of the valve spindle (17) carries a valve cone (18) for the closing of a passage through the piston (8) from the one chamber to the other in the outer tube (2). The valve is spring-loaded (21) for closing, and can be influenced by a release mechanism (23). By opening the valve, the length of the crutch can be adjusted in a stepless manner.

Description: CRUTCH, WALKING STICK AND THE LIKE WITH STEPLESSLY VARIABLE LENGTH. The invention relates to a crutch or walking stick which is steplessly variable in length, comprising an outer tube with at least one inner tube which can be displaced outwards and inwards telescopically by means of a gas spring or other springs, and where the outer tube at the upper end is provided with a handle suitable for the application. Under various conditions, such crutches with adjust¬ able length are of great help to those who have dif¬ ficulty in walking in the non-upright position or when forcing obstacles such as stairs, slopes and under many other circumstances, in that such people ' would be helped by crutches which were shorter in length, and which would help the user to sit down in a chair and get up again without assistance. A crutch of this kind is known from Danish presenta¬ tion document no. 146 917, where the inner tube is slid out by means of a spring which is divided into two chambers by means of a piston, and where a gas or a gas/liquid mixture is led through a connection from the one chamber to the other, depending on whether the crutch is slid out in its fully extended position, or whether it is pressed together. Since a gas is com¬ pressible, and there are limits to how great a pres- sure the gas can have, the crutch will more or less yield when it is loaded. The crutch will thus work in a flexible manner during use, as a consequence of the compressibility of the gas. The object of the invention is to provide a crutch or walking stick of the kind stated, but which is not resilient during use. This is achieved according to the invention by constructing the crutch in such a manner that it comprises a piston rod secured in the upper end of the outer tube, and which extends down¬ wards in the inner tube, where the piston rod is con¬ nected to a sliding piston which divides the inner tube into two chambers, in that the inner tube is closed at both ends and the piston rod is introduced sealingly through the one end, and where the inner tube is filled with a liquid, preferably oil, and comprises a throughgoing valve spindle disposed in a central bore in the piston rod and in the valve plun- ger and provided with a valve cone for the closing of a passage for the liquid through the valve plunger from the one chamber to the other, and at the other end is spring-loaded for closing, and where the gas spring is disposed in the lower end of the inner tube to cooperate with the piston, and also has a release mechanism which influences the valve spindle for the opening of the valve cone. Since the valve piston is secured in the inner tube with liquid on both sides, which is incompressible, during normal use the stick will have a quite fixed length and will not be resil¬ ient. Moreover, when the inner tube is slid out, or respectively when the crutch is pressed together, the liquid will afford a damping effect by passage thro¬ ugh the bore in the piston. The sudden jolt which can arise when one utilizes gas alone or a gas/liquid mixture is hereby avoided. The construction is also better from the technical point of view, the reason being that it is easier to seal completely for liquid than for gas. When the construction of the crutch or stick is in accordance with claim 2, the individual adjustment to that length which suits the person's general way of walking is effected by a known length-adjusting fer¬ rule or other setting arrangement. When the crutch is extended to its full length, it hereby automatically suits the user's general way of walking. This basic setting needs only to be carried out once when the user is supplied with the crutch. The invention will now be described in closer detail with reference to the accompanying drawing, which in a purely schematic manner shows an embodiment of a crutch according to the invention, and where fig. 1 is a longitudinal section through the crutch, in that the handle which would otherwise sit to the right of the fig¬ ure is not shown, just as a ferrule on the lower end of the crutch to the left is not shown, the reason being that these do not serve towards an under¬ standing of the invention, and fig. 2 is a 'longitudinal section on a larger scale of the upper end of the inner tube and the outer tube in shortened form. The crutch according to the invention comprises an outer tube 1 in which there is a telescopically slid- able inner tube 2. To the right of the drawing, the outer tube 1 extends into a not-shown handle, and the inner tube 2 to the left of the drawing extends into a not-shown ferrule. As mentioned in the introduc¬ tion above, the basic adjustment of the crutch can be effected in different ways, e.g. by making the not -shown ferrule adjustable or by providing the crutch with handles and crooks of different lengths. Centrally in the outer tube 1 there is disposed a hollow piston rod 3, the upper end of which is screw¬ ed firmly into a fixing block 4 placed in the upper end of the outer tube 1 and secured between two lock¬ ing rings 5, 6. To prevent the piston rod from work¬ ing loose, it is provided with a counternut 7. The piston rod 3 extends lengthwise in the crutch and down into the inner tube 2, where it is provided with a threaded piston 8 which is sealed against the outer walls of the inner tube by means of hydraulic gaskets 9. The inner tube is closed at both ends. At the outer end it is closed because it is here that a gas cylin¬ der 10 is placed, and at the other end by a cylinder cover 11 which lies against a locking ring 12 and is tightened against the outer wall with an 0-ring 13. The piston rod 3 extends through a central bore in the cylinder cover 11 and is sealed with an O-ring 14. The piston 8 is biased towards the right of the draw¬ ing by the gas spring 10, in that the end of the gas spring's piston rod 15 has a thrust pad 16 which pres¬ ses against the underside of the piston. In the piston rod 3 and the piston 8 there is a through-going bore in which there is a valve spindle 17, on the end of which there is a valve cone 18 with an embedded O-ring 19 for sealing against the under¬ side of the piston. The valve cone 18 is housed in a recess 20 in the gas spring's, thrust pad 16. The val- ve is spring-loaded for closing by means of a coil spring 21 disposed at the opposite end around the valve spindle, and which compresses between the upper end of the piston rod and a stop-ring 22 secured on the valve spindle. The valve can be opened by means of a release device, shown here as a lever 23, which can be turned around an axis 24, and which applies a pressure to the end of the valve spindle 17. The piston 8 divides the inner tube 2 into two cham- bers 25, 26, there being passage for the liquid from the one to the other through the recesses 27 in .the top edge of the thrust pad 16, further through the • bore 28 in the piston 8, and from here further thro¬ ugh a channel 29. For sealing purposes, an O-ring 30 is provided in the upper end of the piston rod. It should be noted that the piston rod 3 and the gas spring's piston rod are of the same dimensions, so that the amount of liquid displaced from the one cha¬ mber corresponds to the empty space arising in the other chamber. The following is a description of the crutch's mode of operation. When a person is supplied with the crutch, the basic setting discussed earlier is car- ried out with the gas spring in its fully-extended condition. The release lever 23 is thus influenced for the opening of the valve, so that there is a pas¬ sage from the chamber 25 through the passage 27,28,29 to the chamber 26, and the gas spring's pressure will slide the crutch out into its fully extended position. If, during use, the crutch is to be made shorter, the crutch is compressed, whereby the liquid will flow from the chamber 25 through the open valve to the chamber 26. If, on the other hand, the crutch is to be made longer after having been pressed together, the pressure is relieved until the pressure of the gas spring overcomes the earlier-mentioned axial force, whereby the gas spring will slide the inner tube 2 outwards, in that liquid will now flow from chamber 26 to chamber 25. When the lever 23 is relea¬ sed, the piston is locked in the liquid so that the crutch has a fixed length. If the user is standing in the upright position, and leans against the crutch thus loading it relatively heavily, and then the re¬ lease lever is operated unintentionally, the crutch is not immediately pressed together, the reason being that the liquid pressure in the lower chamber 25 will press the valve cone 18 for closing. When the user wishes to sit down, the release lever 23 is operated and the crutch is loaded lightly, whereby liquid will flow from the chamber 25 and through the open valve to the upper chamber 26 at the same time that the gas spring is compressed, and the crutch becomes smaller. This helps the handicapped to be eased down into the sitting position rather than dumping down-in the last part of the movement, which is just as irritating as not being able to rise. When the handicapped wishes to stand up again, the release lever 23 is operated once more and the accumulated pressure energy in the gas spring 10 will influence the piston 8. Liquid will now flow from the upper chamber 26 to the lower chamber 25, and thus help the handicapped up into the standing position. The crutch is thus advantageous with regard to use in that it can be steplessly regulated in length, and also in that it is helpful to the handicapped in sit¬ ting down and getting up again. On stairways and sim- ilar places, it can be adjusted to the correct length quickly and easily. Moreover, the crutch is compar¬ able with an ordinary crutch by not being resilient during use, in that the piston 8 is locked in a li¬ quid which per definition is incompressible. In prin- ciple, this corresponds to the crutch being locked mechanically in its individual positions. Purely from the handling point of view, the crutch is made com¬ fortable by a suitable weight distribution by virtue of the gas spring 10 being disposed in the end of the outer tube 2. Another thing is that the crutch does not take up more room than a quite ordinary crutch.

Claims: C L A I M S 1. Crutch or walking stick with steplessly adjustable length, comprising an outer tube (1) with at least one inner tube (2) which can be displaced outwards and inwards telescopically by means of a gas spring or other spring (10) in the lower end, and where the upper end of the outer tube (1 ) is provided with a handle which is suitable for the use, c h a r a c t - e r i z e d in that it comprises a piston rod (3) secured in the upper end of the outer tube (2) , and which extends down into the inner tube (2) where the piston rod (3) is connected to a sliding piston (8) which divides the inner tube (2) into two chambers (25,26), in that the inner tube (2) is closed at both ends and the piston rod (3) is introduced sealingly through the one end, and where the inner tube (2) is filled with a liquid, preferably oil, and contains a through-going valve spindle (17) disposed in a cen- tral bore in the piston rod (3) and in the valve pis¬ ton (8), and is provided with a valve cone (18) for the closing of a passage (27,28,29) for the liquid through the valve piston (8) from the one chamber to the other (25,26), and the other end is spring-loaded for closing, and in that the gas spring (10) is dis¬ posed in the lower end of the inner tube (2) for co¬ operation with with the piston (8) , and also in that it has a release mechanism (23) for influencing the valve spindle (17) for the opening of the valve cone (18) . 2. Crutch or stick according to claim 1, c h a r ¬ a c t e r i z e d in that it comprises an in itself known adjustable ferrule or other setting arrangement for the individual adjustment of the longest length which is suitable for the person's general way of walking.

Inventors: ALLESOEE KURT, ALLESOEE, KURT
Applicants: ALLESOEE KURT, ALLESOEE, KURT
Application year: 1985
Main classification: A61H3
IPC codes: A47B9, A61H3, F16B7