WHEELCHAIRS

DESCRIPTION Technical field

The present invention relates to the technical field comprising wheelchairs for disabled and systems connected thereto to increase the using modes of these aid devices.

In particular, the present invention relates to a universal coupling for an additional wheel for wheelchairs for disabled.

The present invention aims at developing a coupling system for an additional wheel, or other transporting device, for example of parcel grid type, couplable to the wheelchair, in order to increase the using modes.

State of the art

At the state of the art, there are known electric propulsion units for wheelchairs, consisting of electrically motorized wheels which, once connected to a manual wheelchair, convert it into an electric propulsion wheelchair.

Various embodiments of this kind of systems are known, each one being different for the coupling to the frame of a manual wheelchair. For example, electric propulsion units are known, made up of a fork provided with steer, to which an electric motorized wheel is keyed, comprising a battery. The coupling system to the wheelchair is made up of U-shaped tubes, in turn connected to the wheelchair steer tube by means of a pivoting system.

The U-shaped tubes are introduced in holes provided on the clamps connected to the wheelchair frontal portion. By screwing manually actuated screws provided laterally on the clamps it is possible to tighten the tubes inside the holes and by pulling to oneself the wheelchair steer the pivoting system is blocked in a stable position, thus determining the wheelchair frontal wheels to be lifted. The system is thus ready to move the wheelchair electrically .

Devices of this kind are described for example in the Italian Patent 0001417628, in the document US 9,326,901 and in the Italian utility model n° 0000279363 .

Disadvantageously, the just described devices and other similar ones known at the state of the art are difficult to be coupled to the wheelchair.

A first technical problem arises from the fact that the presence of manually actuated tightening screws mounted on the wheelchair frame increases remarkably its lateral dimension, thus making it difficult to enter particularly narrow places with the wheelchair, as for example a lift.

Other producers have solved this problem by arranging gripping couplings only on the electric propulsion unit. But such system results little reliable since each time it is desired to couple the electric propulsion unit to the wheelchair, the disabled user has to come closer to the electric propulsion unit and has to try to actuate it always keeping the same coupling point to the frame. Moreover, such system is not apt to all wheelchair models since the frames are different for dimensions and horizontal or vertical position of their tubes.

There exist also systems provided with a single central coupling. However, such systems are not preferred by the users, since a coupling element is between the legs of the user while sitting in the wheelchair, and this fact results uncomfortable and annoying for the user.

Finally, a common problem to all the embodiments known at the state of the art is the adaptability to the dimensions of the wheelchair frame, which can vary from a wheelchair model to another one for dimension (wheelchair width), for shape (oval, circular or rectangular tube cross-section) and for inclination (the arrangement of the tubes of the wheelchair to which the additional wheel is coupled can be vertical or inclined according to an arbitrary angle).

Aim

Aim of the present invention is to provide a device for coupling an additional wheel to a wheelchair, which can be adapted to any geometry of the wheelchair frame, irrespective of the shape and arrangement of the tubes making up the frame.

More in particular, the present invention provides an adjustable clamp, which can be adapted to the shape and geometry of any wheelchair frame.

Yet, the present invention provides a coupling system of an additional wheel to a manual wheelchair, which is simply couplable both by the user while sitting in the wheelchair and by his assistant .

According to another aim, the present invention provides a coupling system which does not increase the side dimensions of the wheelchair when the additional wheel is decoupled from the wheelchair.

Brief description The present invention realizes the prefixed aims since it is a fastening means of an additional wheel to a wheelchair (26) for disabled, said additional wheel (19) comprising a fork fastened to a steer tube, said fastening means comprising at least a clamp (3) comprising two specular half clamps, each one provided with an inner half housing (25) to house a tube of the wheelchair frame and with a fastening system to said additional wheel, said half-housing (25) comprising a groove with the inclined side surfaces, so that when the two half-housings (25) are faced to each other they can scarf a tube positioned therein, said clamp comprising a first through hole (1) and a plurality of through holes (2), whose centres are arranged along an arc of circle having centre on said first through hole (1).

Detailed description

In a preferred embodiment shown in the appended figures, the coupling for coupling an additional wheel to a wheelchair comprises a shaft (18), hinged transversely in a suitable housing provided on the steer tube of the additional wheel (19) to be fastened to the wheelchair. Once the shaft (18) is in position, it is in horizontal position, at a defined height from the length of the steer tube of the additional wheel.

It is to be specified that the additional wheel (19) for wheelchair (26), known per se at the state of the art, comprises a wheel (20) hinged to a fork, said fork being in turn fastened to a steer tube.

The shaft (18) is hinged to the steer tube, and so it can rotate around its own axis.

Therefore, the device according to the invention comprises blocking means (23) to block the rotation of the shaft (18).

In a preferred but not limiting embodiment, said blocking means (23) comprise screws screwed in a hole provided in the housing of the steer shell in which the shaft (18) rotates, and configured to generate interference, when tightened, with the shaft (18).

At the opposite ends of said shaft (18), two L- shaped side arms (17) are fastened slidingly.

A first end of each arm is introduced on a respective side of said shaft (18), and the sliding movement can be blocked by means of fixing means

(24), such for example interference dowel. The second end of each arm (17) has circular cross section.

The device comprises also a couple of clamps (3), configured to allow the arms (17) to be fastened to the wheelchair frame.

Each clamp (3) comprises two specular half-clamps, each provided with an inner half-housing (25) to house a tube of the wheelchair frame and with a fastening system to the arms (17).

Preferably, the half-housing (25) comprises a groove with the inclined side surfaces, so that when the two half-housings (25) are faced to each other, as it is shown in figure 1, they can scarf a tube positioned therein.

Each clamp (3) is fastened to the tube (17) instead by means of a respective rapid blocking pin (4), described in detail in the following, which can be fastened according to various clamp directions.

To such aim, the pin (4) is provided with a couple of through holes (14, 15) provided on a rod (13), while the clamp is provided with a first through hole (1) and a plurality of circular through holes (2), whose centres are arranged along an arc of circle having centre on the first through hole (1). The clamp is fastened to the rapid blocking pin (4) by means of a couple of screws (16), the first one being introduced in said first through hole, and the second one being introduced in a hole selected between said plurality of circular through holes (2) whose centres are arranged along an arc of circle.

The selection of the hole for the application of the second screw determines clearly the relative inclination of the rapid blocking pin (5) with respect to the housing (25) for the wheelchair frame tube.

In other words, the clamp (3) allows to vary the relative angle between said arms (17) and the tube of the wheelchair, to which the same are fastened. The pin (4), in addition to the rod (13), comprises coupling means configured to fasten removably said pin (5) coaxially to the second end of a respective side arm {11).

To such aim, the pin (4) comprises a terminal thickening (5) next to a groove (6) and an abutment disc (8) provided with a frustum of cone abutment surface (7).

Each side arm (17) comprises a coupling (9) configured to fasten and release easily said rapid coupling pin, so that the same is arranged coaxially to the second end of the respective arm

(17). Preferably, said couplings (9) are introduced in the side arms and fastened by mans of blocking dowels (10), but other fastening means are allowed. The side couplings are provided with an end provided with a beveled inner edge (12), with bevel angle equal to the one of said frustum of cone abutment surface (7), so that the abutment surface can rest on said beveled edge, as it is shown in figure 2.

Each tubular coupling (9) is also provided with a through hole orthogonal to its own axis, inside which a tightening screw (22) with frustum of cone bit is screwed, configured to be introduced inside the groove (6) and to block the pin (4) inside the tubular coupling (9), with the conical portion in abutment on the beveled inner edge.

As yet said, the fact that each one of the clamps (3) comprises two halves, each provided with a first side through hole (1) and on the opposite side a series of through holes (2) arranged along an arc trajectory which as centre has the centre of the first through hole (1), serves to determine the inclination of the pins (4) by adapting to the inclination of the tubes which make up the wheelchair frame. Moreover, preferably, said thickening (5) of each one of said pins (4) is provided with a rounded bit (5), configured to facilitate the introduction of the pins (4) in the tubular couplings (9).

Moreover, being the tightening screws (22) integral to the additional wheel and not to the wheelchair, the dimensions of this latter one is reduced once the portions are decoupled from each other.

It is to be specified, without departing from the aims of the invention, that the additional wheel (19) for wheelchairs can be of electric propulsion type and comprise actuation and control means.

In another embodiment of the invention, the tightening screws (22) with frustum of cone bit, which block the pin (4) inside the tubular coupling (9) can be actuated by an electric motor.

Moreover, the coupling for coupling an additional wheel can be also carried out by using only one clamp (3), only one pin (4) and only one tubular coupling (9).

In order to widen the usage of the invention, the coupling can be used for coupling a transport device, for example of parcel grid type, coupled to the wheelchair.