Abstract:
A foldable crutch having an upper portion and a lower portion of substantially equal lengths, connecting means adapted for pivotally connecting the adjacent ends of the upper and lower portions, and a locking mechanism adapted to hold the upper and lower portions in the linearly stretched state against the pivotal movement.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a crutch. 
     For those who are handicapped in their lower limbs, the crutch is a vital and indispensable instrument which they cannot leave even for a moment in their daily lives. 
     The most serious problem common to all crutched persons resides in the trouble concerning the disposal or storage of the crutch when it is not used, rather than the difficulty in the handling of the same for the walking or the like purposes. 
     Unfortunately, the modern society is leaning to exclude the crutches in its all aspects. Thus, the crutches are becoming hardly accepted. 
     SUMMARY OF THE INVENTION 
     It is therefore a major object of the invention to provide a crutch which can conveniently be folded into a short length when not used. 
     It is another object of the invention to provide a crutch having an upper and a lower portions which are pivotally secured to each other for a 180° rotation. 
     It is still another object of the invention to provide a crutch having a mechanism for locking the upper and lower portions against the relative pivotal movement when the crutch is to be presented for use. 
     It is a further object of the invention to provide a crutch having a locking mechanism which can be handled without difficulty. 
     These and other objects, as well as advantageous features of the invention, will become more clear from the following description of preferred embodiments taken in conjunction with the accompanying drawings in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevational view of a crutch in accordance with the invention, 
     FIG. 2 is a side elevational view of the crutch as shown in FIG. 1, 
     FIG. 3 is a side elevational view of the crutch in the folded state, 
     FIG. 4 is a front elevational view of the crutch in the folded state, 
     FIG. 5 is an enlarged perspective view of the crutch in the locked state, specifically showing the connecting portion of the upper and lower parts of the crutch, 
     FIG. 6 is an enlarged perspective view of the crutch in the unlocked and slightly folded state, specifically showing the same portion as that shown in FIG. 5, 
     FIG. 7 is an enlarged perspective view of the connecting portion with the constituents of the locking mechanism removed, 
     FIG. 8 is an exploded perspective view of the locking mechanism, showing the constituents of the same, and 
     FIG. 9 is a sectional view taken along the line IX--IX of FIG. 5. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings, a crutch embodying the present invention has an upper portion 1 and a lower portion 2 of substantially equal lengths. The upper portion 1 is provided with a handle or a hand-retaining bar 3. The lower end of the upper portion 1 has a pair of forked or U-shaped portions 1a. Each U-shaped portion 1a has a groove 1b extending in the longitudinal direction of the upper portion 1 and at a right angle to the breadthwise direction of the latter. 
     On the other hand, the lower portion 2 is provided with a pair of projections 2a formed on its upper end. These projections 2a are received by the grooves 1b of corresponding U-shaped portions 1a. 
     As will be seen most clearly from FIG. 7, the U-shaped portion 1a and the projection 2 have lateral extensions which are shown, in FIG. 7, to project downwardly from the upper and lower portions 1, 2. Mutually aligned through bores 4 are formed in these lateral extensions of the U-shaped portions 1a and the projections 2a. 
     The common axis X--X of the through bores 4 extends in the breadthwise direction of the crutch and at a right angle to the longitudinal axis of the crutch. 
     As will be seen from FIG. 2, the center X of the through bore 4 is slightly deviated outwardly from the side edges 1c, 2c of the upper and lower portions 1, 2 of the crutch. 
     The upper portion 1 and the lower portion 2 are pivotally connected to each other through a rod 5 which is inserted into the through bores 4. Thus, the lower portion 2 can be swung by 180° around the axis of the rod 5, from the folded position as shown in FIGS. 3, 4 in which it extends in parallel with the upper portion 1 to the stretched position as shown in FIGS. 1, 2 in which it is linearly extended from the upper portion 1. 
     The arrangement is such that the ends 1d of each U-shaped portion 1a abut shoulders 2d formed at both sides of each projection 2a, when the lower portion 2 is rotated by 180° into the stretched position, thereby to prevent the lower portion 2 from being further rotated beyond 180°. It is also possible to prevent the rotation of the lower portion 2 beyond 180° by the abutment of the end surface of each projection 2a and the bottom surface of the corresponding groove 1b. 
     A locking mechanism generally designated at a reference numeral 6 includes a locking bore 7 formed in the U-shaped portion 1a and another locking bore 8 formed in the projection 2a. These locking bores 7, 8 are so arranged that they are brought into alignment with each other when the lower portion 2 is in the stretched position. 
     Guide pipes 9 are fixed to the opposing surfaces of two U-shaped portions 1a, 1a, in axial alignment with respective locking bores 7. Each guide pipe 9 slidably holds a locking pin 10. Each locking pin 10 is fixed to an operation plate 11. These operation plates 11 are fixed to respective pipes 12 which are slidable along the rod 5. A collar 13 is fixed by suitable means to the center of the rod 5. A coiled spring 14 is disposed on each side of the collar 13. These coiled springs 14 are adapted to bias respective operation plates toward the corresponding U-shaped portions 1a, so as to drive the locking pins into the locking bores 7, 8. Two operation plates 11, 11 are spaced apart from each other by such a distance that these operation plates can easily be brought together by fingers of single hand. 
     In use, the lower portion 2 of the crutch in accordance with the invention is locked at the stretched position as shown in FIGS. 1 and 2, with the locking pins 10 received by corresponding locking bores as shown in FIG. 5. 
     For folding the crutch, two operation plates 11, 11 are brought together by fingers as shown in FIG. 6, so that the locking pins 10, 10 may be disengaged at least from the locking bores 8, 8. Then, the lower portion 2 is simply pivoted with respect to the upper portion 1 to the folded position as shown in FIGS. 3, 4. 
     Since the length of the crutch is reduced to half by the folding, the crutch in the folded state can be handled quite easily and can conveniently be stored even in an extremely limited space. 
     Further, the folded crutch can support itself and, therefore, can conveniently be used as a temporary stool, by flattening the lower end of the crutch in the folded state as shown in FIG. 3. 
     Various modifications in structure and/or function may be made to the disclosed embodiments by one skilled in the art without departing from the scope of the invention as defined by the claims.