WO2000064725A1

WO2000064725A1 - A brake system in wheeled walking frames

Info

Publication number: WO2000064725A1
Application number: PCT/SE2000/000745
Authority: WO
Inventors: Ulf Peter SJÖSTRAND; Hubert Erick MALMSTRÖM
Original assignee: Etac AB
Current assignee: Etac AB
Priority date: 1999-04-26
Filing date: 2000-04-19
Publication date: 2000-11-02
Anticipated expiration: 2001-10-26
Also published as: SE9901474L; SE9901474D0; SE514269C2; AU4633300A

Abstract

A brake system in wheeled walking frames or the like comprises a braking device and a handle (10) with a brake lever (20). The braking device acts against a wheel, and the brake lever has a braking position and a locking position. In use, the brake lever actuates the braking device via one end (50) of a connection (40). The other end (43) of the connection (40) abuts against a pressure surface (25, 26) adjacent the brake lever. The brake lever is rotary about two separate rotation centres (23, 24). The one rotation centre (24) functions in the braking position and the other (23) in the locking position.

Description

A BRAKE SYSTEM IN WHEELED WALKING FRAMES

TECHNICAL FIELD

The present invention relates to a brake system in wheeled walking frames, customer trolleys, perambulators or the like, comprising a braking device acting against a wheel and a handle provided with a brake lever which has a braking position and a locking position, and which, in use, actuates the braking device via the one end of a connection whose other end abuts with a certain pressure against a pressure surface disposed adjacent the brake lever, the brake lever being rotary about two separate rotation centres.

BACKGROUND ART

Pursuant to the regulations of most European countries, a wheeled Zimmer frame or walking frame must satisfy certain requirements to be used within public medical care. Among other things, it must be fitted with a brake which is efficient when there is a temporary need to reduce speed, i.e. to impede rolling of the wheels, for example in a downhill position, or in cases where the user risks losing control over the wheeled walking frame. The brake must also be capable of being actuated stationary in order to prevent lurch-rolling, for example when the user needs to take a brief rest and perhaps wishes to use the walking frame as a seat. In this case, the brake must have a stable locking position. There are various types of brakes on the market with this function.

A few examples are those brake systems which are described in WO 93/ 18946 and WO 96/31389.

WO 93/ 18946 discloses an operating device for, for example, a brake in which an operating member is connected to the brake via a connection arrangement which includes a linkage with a first rotation centre and a wire. The operating member is rotatably connected in a second rotation centre with the linkage which in turn is connected to the wire. On temporary braking, the operating member acts on the Unkage without any mutual rotation. The Unkage is rotated only around the first rotation centre. In order to achieve the stable locking position, the operating member is rotated around the second rotation centre, at the same time as a heel on the operating member is appUed against a fixed point. This will have as a result that the second rotation centre is displaced in a rotation movement around the first, which also implies that the linkage is rotated around the first rotation centre and the brake is actuated. To sum up, it may be said that this construction is compUcated and that it requires meticulous maintenance for the rotation of the various component elements to function smoothly.

WO 96/ 31389 also shows an operating device which includes an operating member, a Unkage and a wire which are interconnected to one another in a manner which substantially corresponds to the above-described. The Unkage has two rotation centres as in the foregoing. In a temporary braking, the operating member on the other hand executes a movement around the rotation centre which constitutes its connection with the linkage and lifts the linkage upwards so that this is rotated around the second rotation centre and actuates the brake. In the stable locking position, the operating member is rotated in the other direction around its connection point with the Unkage. A part of the operating member lifts the Unkage upwards so that a movement takes place around the second rotation centre and the brake is actuated also in this case. The drawbacks inherent in this construction are substantially the same as those inherent in the preceding construction.

The present invention is thus applicable to that type of brake which comprises a braking device acting on a wheel, a handle with a rotary brake lever which on adjustment actuates the braking device via one end of a connection whose other end abuts with a certain pressure against a pressure surface disposed adjacent the brake lever. This implies that the brake lever, on rotation from a neutral position, e.g. upwards, temporarily brakes the wheeled frame as long as it is pressed upwards towards the handle and automatically returns to the neutral position when the pressure ceases. On downward rotation, the brake lever falls into a locking position until the user releases it, whereupon it returns to the neutral position.

In such brakes, the connection is subjected to either pressure or drawing. The actual mechanism for transferring the action of the brake lever on the connection takes place as described above with different types of Unkages or eccentric movements.

PROBLEM STRUCTURE

The object of the present invention is to realise a simplification of the mechanism for achieving the rotational movements which in turn give the desired braking function.

SOLUTION

This object is attained by means of the present invention in that the brake lever is made rotational about two separate rotation centres, which, in the neutral position of the brake lever, are both active in order, on rotation in either direction, to lose its function as a rotation centre, while the rotation takes place about the other rotation centre.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

With a view to more closely explaining the present invention, a representative embodiment thereof will now be described in greater detail hereinbelow, with reference to the accompanying Drawings, Figs. 1-3, which show a cross section taken through a braking mechanism in different action phases. In the accompanying Drawings:

Fig. 1 shows the mechanism in neutral position;

Fig. 2 shows the mechanism in normal braking; and

Fig. 3 shows the mechanism in the locking position.

DESCRIPTION OF PREFERRED EMBODIMENT

The major parts included in the brake system are a handle 10, a brake lever 20, a bearing housing 30, a connection 40 and a braking device 50. Further, there is a strap 60 which connects the handle 10 and the brake lever 20. The bearing housing 30 is disposed on or immediately adjacent the handle 10. The brake lever 20 is disposed to extend partly into the bearing housing 30 and partly to project out beyond it.

The brake lever 20 in principle consists of two mutuaUy rigidly connected portions, a gripping portion 21 and a functional portion 22, which in turn include two rotation centres, an outer 23 and an inner 24. Both of the rotation centres 23, 24 include parts of the bearing housing 30 and the functional portion 22 which cooperate with one another. The rotation centre 23, which is the front centre in the normal direction of travel, comprises, in the preferred embodiment, a concave surface in the bearing housing 30 and a convex portion on the functional portion 22. The rear rotation centre 24 includes a convex surface in the bearing housing 30 and a concave portion on the functional portion 22.

The functional portion 22 further has two convex contact portions 25 and 26 which, under pressure from a helical spring 44, sUde against two surfaces 41 and 42 disposed on the upper end 43 of the connection 40. The upper surface 41 is concave and sUdes against the convex contact portion 25. The lower surface 42 is convex and sUdes against the convex contact portion 26 which has a recess 27 whose form permits accommodating the surface 42 which, in the preferred embodiment, is a pin.

On temporary braking, as iUustrated in Fig. 2, the gripping portion 21 of the brake lever 20 is pressed in a direction towards the handle 10 under compression of the helical spring 44. The brake lever 20 wiU, in this instance, be rotated about its inner or rear rotation centre 24 and the contact surface 25 will then slide against the surface 41 on the end 43 of the connection 40 as shown in Fig. 2. During the compression of the spring 44, the connection 40 will be pressed downwards and the braking device 50 will enter into function (not shown in the Figures). After the braking operation, the brake lever 20 automatically returns to the neutral position according to Fig. 1 under the action of the force from the helical spring 44. In the temporary braking, the rotation takes place entirely about the rear rotation centre 24, while the front rotation centre 23 is inactive, since its convex and concave surfaces, respectively, are no longer in contact with each other. In order to bring the brake to the fixed locking position as Ulustrated in Fig. 3, the brake lever 20 is pressed downwards, also now under the compression of the heUcal spring 44, but with the difference that the rotation centre 23 is now different. On this rotation, the sliding surface 26 which, as was mentioned previously, is provided with a recess 27, will come into contact with a pin 42 on the upper end 43 of the connection. When the recess 27 passes the pin 42, the latter falls into this recess 27 and locks the brake lever

20 in this position with a certain force. At the same time, the parts included in the rotation centre 24 are not in contact with each other and the centre 24 can thereby be said to be inactive.

The force which is subsequently needed for releasing the brake from the fixed locking position is, granted, not particularly large, but may entail certain problems for a weak hand if the user must, at the same time, support against the handle. In order to facilitate this release action, the brake system is therefore provided with a strap 60, preferably of textile, whose ends are connected to the handle 10 and the brake lever 20, respectively. A Ught pressure from one finger against the strap in this position as shown in Fig. 3 (with the hand stiU remaining on the handle), gives sufficient force to release the brake. On actuation of the strap 60, the upper end of the gripping portion

21 is lifted upwards, and the functional portion 22, which is rigidly connected to the gripping portion 21, is given an upward movement, around the rotation centre 23. In such instance, the recess 27 moves away from the pin 42. When the pin 42 is no longer located in its locking position in the recess 27, it is actuated upwards by the spring 44 until it comes into contact with the convex surface 26. During the continued rotation of the functional portion 22, the pin 42 will slide along the convex surface 26, and the connection 40 will move upwards. This entails that the braking device 50 is no longer appUed.

Claims

WHAT IS CLAIMED IS:

1. A brake system in wheeled walking frames, or the like, comprising a braking device acting against a wheel and a handle (10) provided with a brake lever (20) which has a braking position and a locking position, and which, in use, actuates the braking device via the one end (50) of a connection (40) whose other end (43) abuts with a certain pressure against a pressure surface (25, 26) disposed adjacent the brake lever, the brake lever (20) being rotary about two separate rotation centres (23, 24), characterized in that the rotation centres, in the neutral position of the brake lever, are both active in order, on rotation in either direction, to lose its function as a rotation centre, while the rotation takes place about the other rotation centre.

2. The brake system as claimed in Claim 1, characterized in that both rotation centres (23, 24) are disposed in a bearing housing (30) secured to the handle or integrated therewith.

3. The brake system as claimed in Claim 1 or 2, characterized in that a flexible strap is secured between the handle (10) and the brake lever (21) of a length which is at least equal to the distance between the anchorage points of the strap when the brake is in the locking position.