GB1580956A

GB1580956A - Mobile invalid chair

Info

Publication number: GB1580956A
Application number: GB3046277A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-03-05
Filing date: 1977-07-20
Publication date: 1980-12-10
Also published as: NL7707951A; DE2709618A1

Description

(54) MOBILE INVALID CHAIR (71) I, GAUNTER MEIER, a Citizen of the Federal Republic of Germany, of Bruchstrasse 7, D-4951 Holtrup, Federal Republic of Germany, do hereby declare the invention, for which I pray that a patent may be granted. to me, and the method by which it is to be performed, to be described in and by the following statement; The invention relates to a mobile invalid chair, in the form of a push-chair with four wheels.

Mobile chairs of various types are already known. In this context, one also speaks of invalid wheelchairs. Normally, a distinction is made between a self-propelled chair with manual control, electric- and motoroperated invalid wheelchairs and what are known as push-chairs.

The manually-controlled self-propelled chair may be either of collapsible or of rigid design. Self-propelled chairs are preferred by those lame persons who wish to travel longer distances under their own power.

Due to their practical design, these selfpropelled chairs are suitable for use on the road and also for moving about in largeroomed buildings such as clinics, homes, factory floors, exhibition halls, etc. Movement is effected by means of a lever control, operation of this lever control requiring normal arm strength. The control canefit- ted on the right or on the left or on both sides.

Furthermore, wheelchairs are known which have large rear wheels. These rear wheels are provided with what are known as hand rims, by means of which the lame person can move himself together with the wheelchair.

Invalid wheelchairs driven by an electric motor are also either of a collapsible or rigid design. The controls of these invalid wheelchairs vary very widely, so that even very severely handicapped persons can operate these vehicles.

As far as push-chairs are concerned, this is understood to be a chair provided with wheels, which has to be pushed by an accompanying person. Its two side frames are connected to each other by transverse bars. However, where push-chairs are concerned, its should be borne in mind that they should not only be comfortable for the lame person, but should also be easy to operate by the accompanying person.

In this connection, a push-chair has e.g.

become known in which the two front wheels are mounted so that they can swivel through 360 degrees around a vertical axis.

For this purpose, the two front wheels are considerably smaller than the two rigid rear wheels. These front wheels, which can rotate through 360 , enable the push-chair to be steered relatively easily on smooth ground. On rough ground, these small swivelling wheels prove to be a disadvantage, as the small front wheels are unintentionally deflected whenever they meet an unevenness in the ground. Consequently, the accompanying person is required repeatedly to point the push-chair in the direction of travel. It is obvious that, with an occupied push-chair, this is not always easy.

With another type of push-chair, four wheels of equal size are provided, these wheels being rigidly mounted. For major changes in the direction of travel, this pushchair is steered like a pram, i.e. the chair is tilted slightly upwards from the rear wheels and brought into the desired direction of travel. This design has been found particularly suitable on paths sloping to the side and on rough ground. As the handles in the area of the backrest are of an extended design, light pressure is sufficient to lift the two front wheels off the ground. It has now been found in practice that a push-chair with rigidly suspended wheels of equal size is relatively difficult to steer in the laden condition.

All things considered, push-chairs of known types have a common drawback, in that satisfactory steering of these push chairs in a laden condition is not possible.

Knowing these drawbacks, the inven tor-himself having been involved for years in helping handicapped persons-set himself the task of providing a push-chair which is equipped with four wheels preferably of equal size and which ensures optimum steer ing of one pair of wheels, controlled by the accompanying person.

According to the invention there is provided a mobile invalid chair which is pushed by an accompanying person and which com prises a chair frame which is provided with four wheels on wheel mountings connected to the frame and which supports a seat and a backrest and on which there is arranged a steering means for the front or rear pair of wheels, which steering means is operable by the accompanying person, wherein the steering means comprises a track rod link age connecting the two wheel mountings of the steerable pair of wheels, which mount ings can each be swivelled about a vertical axis, and a control rod linkage comprising a pull and push rod, of which one end is pivot ally connected to a wheel swivel mounting, a bell-crank lever pivotable about a horizontal axis axis and extending in the direction of travel in a chair frame side area beneath the seat and having one arm pivotally connected to the other end of said pull and push rod and a further rod pivotally connected at its lower end to the other arm of said lever and extending behind the backrest in the vertical direction, the upper end of said further rod being pivotally connected to a rotatable handle.

The track rod linkage of the swivelling pair of wheels may be formed of two parts and consists of one short lever arm fixed to each wheel mounting, between which a track rod, adjustable for length, is flexibly fitted.

The rod running behind the backrest may be flexibly connected to one of the handles of the chair frame, this handle being designed to rotate or swivel. The two tie rods which move during the steering opera tion may be adjustable for length and have a ball socket at each end.

Preferably, the crank lever located bet ween the two rods has a long horizontal arm and a short vertical arm, these two arms each having a ball head to accommodate the ball sockets of the two rods. Furthermore, a short arm may be attached to the wheel mounting and also has a ball head and retains the front ball socket of the pull and push rod.

Finally, it should be mentioned that the chair frame may be provided with a stop dog for limiting the extent of tilt of this crank lever.

The following description serves as an explanation of the subject of the invention, one embodiment of which is represented in the drawings, wherein: Figure 1 shows a side elevation without the wheels on the right-hand side of the chair, and Figure 2 shows a view from the rear.

As can be seen from Figure 1, the mobile invalid chair is fitted with four wheels of equal size 1, 2 having pneumatic tyres. The wheel pairs 1 and 2 are mounted on the chair frame 3 in such a way that one wheel pair can swivel while the other wheel pair has a rigid mounting. In the embodiment, the wheels of front wheel pair 1, with the corresponding wheel suspensions 10, are mounted so that they can swivel.

The two swivelling wheels 1 are connected with each other via a steering linkage consisting of two short lever arms 4 with a track rod 5 positioned in between. The two lever arms 4 are welded to the wheel suspensions 10. The connections between lever arms 4 and the ends of the track rod 5 are pivotable.

One of the wheel suspensions 10 is fitted with an arm-like projection 13 positioned at right angles and extending into the chair frame 3, this projection 13 having a ball head 14 engaging a the front ball socket 12 of the rod 7 in a retaining manner. The rear ball socket 12 of the rod 7 is carried by a bell crank lever 11 with ball head 14. The crank lever 11 itself is fitted in the lower sector of the chair frame so that it can pivot around a fulcrum and, by means of a second ball head 14, retains the lower ball socket 12 of the rod 8, which runs parallel to the backrest 6 of the chair. The upper ball socket 12 of the rod 8 is connected to one of the handles 9 via a ball head 14 or similar, the respective handle 9 being formed so that it can rotate or swivel.

In the embodiment, the handle 9 on the right is in the form of what is known as a twist grip. This twist grip handle 9 has a horizontal projection 9 with ball head 14.

On the push-chair, steering of the two swivelling wheels 1 takes place as described in more detail below: If the accompanying person turns the twist grip 9 to the right, the rod 8 coupled to the grip 9 moves upwards, pulling the long arm of the crank lever 11 with it, while the short arm of the latter 11 moves around the pivotal point in the direction of travel and the front wheels 1 are subjected to a deflection to the right via the rod 7 and arm 13, whereby, of course, the swivelling movement of the steered right-hand wheel 1 is transmitted to the left-hand wheel 1 via the rods4,5.

If the twist grip 9 is turned to the left, the rod 8 moves downwards via the projection 9, on the handle 9, whereby the long arm of the crank lever 11 is also moved downwards and the short arm of the latter 11 is moved to the rear. During this operation, the rod 7 forcibly pulls the arm 14 against the direction of travel and the steered wheels 1 are deflected to the left. In each of the aforementioned cases, satisfactory turning through bends is achieved with relatively little effort on the part of the accompanying person. A stop dog 15 on the chair frame 3 limits the tilting movement of the crank lever 11. Thus, the steering deflection of the front wheels 1 can also be adjusted and limited.

In order to ensure perfect movement between the individual elements participating in the steering process, i.e. lever arms 4, track rod 5, rods 7, 8, crank lever 11 and handle projection 9', ball sockets 12 and ball heads 14 passing into these sockets are provided at the respective points of contact.

As already stated initially, the description given above refers to only one embodiment.

t may, however, be stated that the subject of the invention permits variations without departing from the scope of the invention defined by the claims.

WHAT I CLAIM IS: 1. A mobile invalid chair which is pushed by an accompanying person and which comprises a chair frame which is provided with four wheels on wheel mountings connected to the frame and which supports a seat and a backrest and on which there is arranged a steering means for the front or rear pair of wheels, which steering means is operable by the accompanying person, wherein the steering means comprises a track rod linkage connecting the two wheel mountings of the steerable pair of wheels, which mountings can each be swivelled about a vertical axis, and a control rod linkage comprising a pull and push rod, of which one end is pivotally connected to a wheel swivel mounting, a bell-crank lever pivotable about a horizontal axis and extending in the direction of travel in a chair frame side area beneath the seat and having one arm pivotally connected to the other end of said pull and push rod, and a further rod pivotally connected at its lower end to the other arm of said lever and extending behind the backrest in the vertical direction, the upper end of said further rod being pivotally connected to a rotatable handle.

2. A mobile invalid chair as claimed in claim 1, wherein the bell crank lever is provided with arms of unequal length and in that said further rod is pivotally connected to the distal end of the longer arm, which extends approximately horizontally, and the pull and push rod is connected to the shorter leg, which is approximately vertical.

3. A mobile invalid chair as claimed in claim 1 or 2, wherein the pull and push rod is connected, with the end that is directed away from the bell crank lever, to an arm attached to the wheel mounting.

4. A mobile invalid chair as claimed in claim 1, 2 or 3, wherein a stop for limiting the swivel movement of the crank lever is mounted on the chair frame.

5. A mobile invalid chair as claimed in any one of claims 1 to 4, wherein the two rods are so designed that they can be adjusted within themselves in length.

6. A mobile invalid chair as claimed in any one of claims 1 to 5, wherein the track rod linkage is formed by a track rod and two lever arms which are arranged on the two wheel mountings and are pivotally connected to the track rod.

7. A mobile invalid chair as claimed in any one of claims 3 to 6, wherein the pivotal connections between the rods and the lever arms and the crank lever respectively and the arm attached to the wheel mounting respectively and the handle respectively are each formed by ball-and-socket joints.

8. A mobile invalid chair substantially as described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. 9, on the handle 9, whereby the long arm of the crank lever 11 is also moved downwards and the short arm of the latter 11 is moved to the rear. During this operation, the rod 7 forcibly pulls the arm 14 against the direction of travel and the steered wheels 1 are deflected to the left. In each of the aforementioned cases, satisfactory turning through bends is achieved with relatively little effort on the part of the accompanying person. A stop dog 15 on the chair frame 3 limits the tilting movement of the crank lever 11. Thus, the steering deflection of the front wheels 1 can also be adjusted and limited. In order to ensure perfect movement between the individual elements participating in the steering process, i.e. lever arms 4, track rod 5, rods 7, 8, crank lever 11 and handle projection 9', ball sockets 12 and ball heads 14 passing into these sockets are provided at the respective points of contact. As already stated initially, the description given above refers to only one embodiment. t may, however, be stated that the subject of the invention permits variations without departing from the scope of the invention defined by the claims. WHAT I CLAIM IS:

1. A mobile invalid chair which is pushed by an accompanying person and which comprises a chair frame which is provided with four wheels on wheel mountings connected to the frame and which supports a seat and a backrest and on which there is arranged a steering means for the front or rear pair of wheels, which steering means is operable by the accompanying person, wherein the steering means comprises a track rod linkage connecting the two wheel mountings of the steerable pair of wheels, which mountings can each be swivelled about a vertical axis, and a control rod linkage comprising a pull and push rod, of which one end is pivotally connected to a wheel swivel mounting, a bell-crank lever pivotable about a horizontal axis and extending in the direction of travel in a chair frame side area beneath the seat and having one arm pivotally connected to the other end of said pull and push rod, and a further rod pivotally connected at its lower end to the other arm of said lever and extending behind the backrest in the vertical direction, the upper end of said further rod being pivotally connected to a rotatable handle.