SHOCK ABSORBER FOR CRUTCHES

Abstract: The device applies to crutches wherein are provided two telescopic tubes (6, 7) which, on the one hand, make possible adjusting the effective height of the crutch and, on the other hand, absorb the impact of the crutch to the ground, the device consisting of a bush (13) which is fitted to the upper extremity of the lower telescopic tube (6) and which has an elongate side hole (15) wherein a pin (11') can play and is secured to the upper external tube (7), precisely through a pair of orifices (12) drilled in said tube so that the length of the elongate orifice (15) of the plug limits the relative motion between the two tubes (6, 7) forming the strut (1), said elements being maintained at a maximum distance from each other by means of a spring (10) positioned between the plug (13) and the second pin (11) of the upper and external tube.

Description: OBJECT OF THE INVENTION This invention relates to a shock absorber for crutches. With it, crutches offer the best conditions regarding user's comfort through a damped support on the ground. The device has been conceived and arranged in order to arrive at a considerable reduction in price of the crutch. BACKGROUND OF THE INVENTION Utility model number ES 1034631Y which was not published before the filing date of the present application and thus does not belong to the state of the art according to Art. 54(2) nor 54(3) EPC, from the same applicant, describes a crutch with which several problems and difficulties are solved. These derive from the framework or basic constitution of traditional crutches, whether they are finished off by a cross-piece made to be adapted to the armpit of the user, or they are those where the upper end is finished off by a semi-clamp to be adapted on its side to the arm, close to the user's elbow. Therefore, in the utility model, the novelty of the crutch is described as being the structure between the traditional cross-piece for the support of the user's hand, and the lower end for the support of the crutch on the ground. The structure is characterized by a telescopic strut, based on two sectors that are axially interconnected. So, the lower sector or span acts as a female element while the upper sector or span acts as a male element, with the particularity that between both sectors or spans and internally, a bumper is placed to absorb the effects of the crutch impact on the ground, when walking, and more precisely, the effects that the impact produce on the member which is holding it down and which is transmitting the corporal weight to it. This solution, avoids the typical "shock" at the upper extremities of people using crutches to walk, which "shock" effect can produce pathological irregularities in the individual such as the so-called "crutch syndrome" and which is characterized by neurological irregularities in the arms, caused by the injury of the brachial plexus when passing through the armpit region. Logically, structural characteristics of the crutch, which is the object of the utility model 9601865, with regard to its telescopic capability and its bumper device incorporated by the lower strut of the crutch itself avoid or solve the troubles we just have explained. Trying to improve the features of this kind of crutch, the applicant himself is the holder of the utility model ES 1036959Y which was also not published before the filing date of the present application and hence also does not belong to the state of the art according to Art. 54(2) nor (3) and in which, starting from a configuration similar to the one of the utility model ES1034631Y previously quoted, it has been foreseen that the damping itself could be controlled as a result of providing a spring capable of being arranged so as to have a larger or smaller degree of extensibility. Also, this damping can be cancelled without needing to pull out the spring but rather by changing the position of a pin, which pin not only serves as a fixing part for connecting the two pipes that constitute the lower strut of the crutch, but also makes possible the damping because this pin is placed in a vertically extended window of the lower, internal pipe, of the two pipes making up the lower strut of the crutch. This solution, which is suitable from a functional point of view, represents in any case, an economical problem due to the costs providing the extended window in the pipe making up the strut. DESCRIPTION OF THE INVENTION The device proposed by the invention, starting from a performing philosophy of the utility model ES 1036959Y solves in a completely satisfactory way, the troubles explained above as it makes unnecessary any kind of machining in the pipe forming the strut. Document GB-A-141109 is a document of the state of the art which is relevant to the present invention. For this and in a more concrete way, taking into consideration that it is necessary to "fit in" the upper end of that strut to a cap provided with an upwardly extending axial rod to guide the spring that supplies the crutch with the bumper effect, this invention is ) characterized by extending the body of the cap to enable establishment of the elongated window or hole therein to absorb the telescopic motion of the strut against the elastic deformation of the spring, as well as a hole necessary to cancel the bumper effect through a position change of the corresponding pin. In this way and as it has been said above, the pipe forming the strut does not require any machining and the part forming the cap, as it has been obtained from plastic material and through injection, has a cost nearly the same, with or without the holes. Therefore, the economic repercussion that the presence of these parts represents, is no more than the necessary material cost for its extension, and this material cost is considerably lower than the former costs of the pipe machining. DESCRIPTION OF THE DRAWINGS In order to complete the description which is being made and with the aim of helping to a better understanding of the characteristics of the invention, according to a preferable example of its practical realization, it is enclosed as an integral part of that description, a set of drawings where, on an illustrative and not restrictive basis, it has been represented what follows: Figure 1 shows an exploded perspective view of a crutch provided with a bumper device according to the present invention. Figure 2 shows an enlarged detail and side elevation of the bumper device of this invention. DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION From these figures it can be observed that this crutch includes a lower strut (1), finished off at its end with a shoe or a non-slipping rubber plug (2), as a support element on the ground. The lower strut (1) is straight and incorporates an upper cross-piece (3) for the support of the user's hand. From the cross-piece (3) is extended a second span or upper strut (4) which is not very long and follows an oblique path with regard to the lower strut This second span is finished off by atypical semi-clamp (5) adapted to receive the user's arm, close to his elbow. The lower strut (1) is formed of two pipe sections (6) and (7) inter-connected in a telescopic way, and the upper strut (4) is formed of two pipe sections (8) and (9), with the pipe (8) being the external one and the pipe (9) being the internal one, but the former remaining in an upper disposition. The two pipe sections (6) and (7) of the lower strut (1) telescopically slide between limit positions against the stress of a spring (10) supported on the top by a pin (11), established in one of the many holes (12) of the pipe (7), and supported on the other end by a cap (13), connected to the upper end of the pipe (6) and provided with a rod or axial extension (14) serving as a guide for that spring (10). A second pin (11') holds together the two pipes (6) and (7) which make up the lower strut (1). Starting from this basic and conventional structure, this invention focuses on how the pipe (6) is related to the pipe (7) by the pin (11'). As best seen in Figure 2, the cap (13) incorporates a transverse, longitudinally elongated hole (15), in which the pin (11') can slide and a circular hole (16) in which the pin (11') can be introduced when it is desired to block relative telescopic movement of the two pipes (6) and (7) that make up the strut (1).In this way the bumper or shock-absorbing effect can be eliminated without eliminating the spring (10). In this way, the holes (15) and (16) which previously had to be machined in the lower pipe (6), can be formed in the injection formation of the cap (13) itself, thereby realizing a reduction in costs. It is not considered as necessary to make this description more extensive in order that any expert in this matter could understand this invention and the advantages derived from it. Materials, shape, size and positions of the elements could be changed when it will not represent an irregularity in the essence of this invention. The terms used in this description should always be taken in a broad and not restrictive sense.

Claims: A shock absorber for a crutch, having a lower strut (1) formed of an upper pipe (7) and a lower pipe (6) which are telescopically connected, the upper pipe (7) having diametrical holes (12) a pin (11) disposed in a selected one of the diametrical holes (12) of the upper pipe (7) and a spring (10) operatively supported between the lower strut (1) and the pin (11) to provide shock absorbing during telescopic movement of the lower pipe (6) relative to the upper pipe (7) said shock absorber comprising a cap (13) attachable to a top end of the lower pipe (6) said cap (13) having an upwardly extending axial guide rod for receiving the spring (10) thereon, the cap (13) having formed therein an axially elongated hole (15) and a circular hole (16) and a lower pin (11') selectively engageable in a shock absorbing position in which said lower pin (11') is fixed relative to the upper pipe (6) and extends into said axially elongated hole (15) of said cap (13) to allow play between said cap (13) and the upper pipe (7), and in a non-shock absorbing position in which said lower pin (11') is fixed relative to the upper pipe (6) and extends into said circular hole (16) of said cap (13) to prevent play between said cap (13) and the upper pipe (7). A shock absorber according to claim 1 characterized in that said lower pin (11') is selectively engageable in the diametrical holes (12) of the upper pipe (7), such that, in said shock absorbing position, said lower pin (11') is engaged in one of the diametrical holes (12) of the upper pipe (7) and extends into said axially elongated hole (15) of said cap (13), and in said non-shock absorbing position, said lower pin (11') is engaged in one of the diametrical holes (12) of the upper pipe (7) and extends into said circular hole (16) of said cap (13).

Inventors: REHBERGER OLIVERA JORGE, REHBERGER OLIVERA, JORGE
Applicants: REHBERGER OLIVERA JORGE, REHBERGER OLIVERA, JORGE
Application year: 1997
Main classification: A61H3
IPC codes: A61H3