GB2218321A

GB2218321A - Safety belt locking system

Info

Publication number: GB2218321A
Application number: GB8909698A
Authority: GB
Inventors: Klaus Struck
Original assignee: Autoflug GmbH
Current assignee: Autoflug GmbH
Priority date: 1988-04-27
Filing date: 1989-04-27
Publication date: 1989-11-15
Also published as: IT8920287A0; IT1229682B; GB8909698D0; SE8901251L; DE8816575U1; DE3814247A1; FR2630692A1; SE8901251D0

Description

1 11 22 18521 1 54077.02 Belt lockinq device The invention relates to a

belt locking device for safety belts, particularly in motor vehicles, comprising a self-locking belt reeling means and a clamping device, fixed to the vehicle, which causes locking of the belt, said clamping device having one fixed clamping jaw and one movable clamping jaw which enclose the belt between them, the belt reeling means in the locked state as a whole actuating the clamping device and being held by spring force in the rest position.

A belt locking device of this kind is described in DE-OS 35 10 673; the belt reeling means are pivotally mounted in the housing fixed to the vehicle and are coupled to the movable clamping jaw of the clamping device acting on the belt via a transmission member in the form of an angled lever or push rod. After the belt reeling means have been locked by means of the vehiclesensitive or belt-sensitive locking system acting thereon, the increase in the belt withdrawal force acting on the belt results in pivoting of the belt reeling means and this pivoting movement is converted, via the transmission member, into a corresponding movement of closure of the movable clamping jaw of the clamping device.

This known belt locking device has the disadvantage that a considerable number of components are required and the control of the movement conversion by means of the precision components required for this purpose demands a corresponding degree of precision and expense in manufacture; moreover, the plurality of coupling points between the operational parts of the belt locking device must be regarded as possible weak points in terms of the loading action of the belt locking device, and finally the operation of the system, with the interaction of a plurality of components, takes a 2 corresponding amount of time.

The aim of the invention is therefore to simplify the manufacture of a belt locking device of this kind, make it safer in terms of the loading action and at the same time shorten the reaction time from the actuation of the belt locking device until the wearer of the belt is securely restrained.

Thus according to the invention the belt reeling means and the movable clamping jaw are constructed as a structural unit which is pivotable about a spindle fixed to the housing, whilst the lever arm between the rotation spindle of the structural unit and the line of action of the spring which biases the structural unit into its rest position is smaller than the lever arm effective between the rotation spindle and the point of exit of the belt from the belt reeling means. This arrangement has the advantage that, because of the effective lever ratio, even a small increase in the belt withdrawal force will be sufficient to overcome the spring force which biases the structural unit consisting of belt reeling means and movable clamping jaw into its rest position, with the result that the structural unit is pivoted onto the emerging belt and the movable clamping jaw clamps the belt against the fixed clamping jaw. As the belt withdrawal force increases further, the clamping forces are intensified.

A further advantage is that as the clamping action begins no further belt forces build up between the clamping device and the belt reeling means, since the length of belt located on the belt winding spindle of the belt reeling means travels the same distance as the movable clamping jaw when the belt locking device acts.

In order to provide a pivoting path for the structural unit, the point of exit of the belt from the belt reeling means is at a spacing from the clamping plane of the clamping device. The necessary deflection of the belt before it enters the plane of the clamping fl M 3 device is effected by means of a fixed belt guide which, on both sides of the clamping device, ensures that the belt can pass through, without making any contact, when the clamping device is open; the belt guide provided between the clamping device and the belt reeling means is at the same time constructed as an abutment for the structural unit consisting of belt reeling means and movable clamping jaw which is spring loaded into the rest position.

The belt locking device according to the invention can thus be manufactured with only a few individual components of simple construction, whilst the belt reeling means with their vehicle-sensitive and beltsensitive locking system need not themselves be designed to bear any load, since the restraining forces which occur are absorbed by the clamping device. Consequently, the belt reeling means may be made of plastics, for example.

As an additional safety measure, according to one embodiment of the invention the belt winding spindle of the belt reeling means may be designed as a load-bearing component and an abutment may be formed in the housing which holds the belt locking device, the belt reeling means being arrestable on said abutment when they are pivoted into the clamping position; this ensures that if the clamping jaws should fail the support of the belt winding spindle in the housing which is fixed to the vehicle will ensure that the force is absorbed and carried away. 30 The drawings show an embodiment by way of example of the invention which will be described hereinafter. In the drawings: Fig. 1 shows a belt locking device in a partly cutaway side view, in the operational state with the clamping device open, Fig. 2 shows the belt locking device of Fig. 1 in the locked position with the clamping device closed.

4 The belt locking device has belt reeling means 10 with a belt winding spindle 11 on which the belt 12 is wound. The belt reeling means 10 have a vehicle sensitive locking system with a locking wheel 13 with external teeth, into which a locking lever 15 can engage, under the control of a ball sensor 14. The belt reeling means 10 also have a belt-sensitive locking system with an internally toothed ratchet wheel 16 fixed to the housing and a locking lever 18 which is controlled by a spring 17 in response to the speed of withdrawal of the belt 12 from the belt winding spindle 11.

The clamping device arranged in a housing 20 which can be secured to a structural part of the vehicle by means of securing means 19 comprises a clamping jaw 21 fixed to the housing and a movable clamping jaw 22, pivotally mounted in the housing 20 so as to be rotatable about a pivot spindle 23. The movable clamping jaw 22 and the belt reeling means 10 form a structural unit which is pivotable in its entirety about the spindle 23.

Lateral plates 29 are mounted as projections on the movable clamping jaw 22, on both sides thereof, the belt winding spindle 11 being supported in said plates 29.

Since the plates 29 do not have to bear any load, they may be made of plastics, for example.

The movable clamping jaw 22 respectively the entire structural unit with belt reeling means 10 is biased by a spring 24 against an abutment 25 fixed to the housing, in the operating position when the clamping device is open, and this abutment 25 simultaneously serves as a fixed belt guide to introduce the belt 12 leaving the belt reeling means 10 at an exit point 27 into the plane of the clamping device 21, 22.

Since the point of exit 27 is at a spacing from the clamping plane defined by the surface of the fixed clamping jaw 21, in order to provide a pivoting path for si 1 1 the structural unit consisting of belt reeling means 10 and movable clamping jaw 22, the belt 12 which, in the open position of the belt locking device, approaches the clamping device 21, 22 at an angle has to be deflected into the clamping plane so as to be able to pass through between the clamping jaws 21, 22 in the open position without making any contact. For this purpose, the belt guide 25 is arranged opposite the lower end of the clamping jaw 21 and spaced therefrom and is supplemented by an associated belt guide 26 above the clamping jaw 21.

The operational parts 10 and 24 of the belt locking device are arranged in a specific leverage ratio relative to the rotation spindle 23 of the structural unit 10, 22: the spring 24 in a line of action extending parallel to the plane of exit of the belt 12, at a spacing a, defining a lever arm, from the rotation spindle 23, and the belt reeling means 10 as regards the point of exit 27 with an effective lever arm b from the rotation spindle 23.

If the point of exit 27 of the belt 12 from the belt reeling means 10 changes slightly depending on the thickness of the length of belt left on the belt winding spindle 11, this has no appreciable effect on the basic realisation of the invention.

If, during actuation either of the vehicle sensitive locking means 13, 14, 15 or of the belt sensitive locking means 16, 17, 18 in the belt reeling means 10, in known manner which needs no further explanation, there is locking of the belt winding spindle 11 against further withdrawal of the belt, a belt withdrawal force Fb.1t arises accordingly in the belt 12 which, with the effective lever arm b relating thereto, must be seen in comparison with the force of the spring 24 counter to the belt withdrawal force = Papring and the effective lever arm a thereof. Because the lever arm b is greater than the lever arm a even a 6 minimal increase in the belt withdrawal f orce Fbelt effective in the belt 12 will be sufficient to overcome the force Fspring and pivot the structural unit consisting of belt reeling means 10 and movable clamping jaw 22 about the rotation spindle 23 onto the belt and by engagement of the clamping jaws 21, 22 bring about clamping of the belt 12.

Since the clamping jaws 21, 22 are provided with a friction-increasing lining 28 or alternatively constructed with teeth, in known manner, the force acts reliably at the start of the clamping action, so that the force effective in the belt increases further And increases the contact pressure of the clamping device still more as a result of the leverage conditions described above. This ensures that the restraining forces are safely transmitted to the housing 20 which secures the clamping device 21, 22 fixedly to the vehicle, so that the belt reeling means 10 do not have to absorb any forces.

Although this is not shown in detail, as an additional safety measure an abutment for the belt winding spindle 11 of the belt reeling means 10 may be formed in the housing 20 which is secured to the vehicle, in this case the belt winding spindle 11 of the belt reeling means being designed to be load-bearing. In such an embodiment, should the clamping action of the clamping device fail the belt winding spindle 11 is guaranteed to absorb the restraining forces occurring and transmit them via the associated abutment fixed to the housing into said housing fixed to the vehicle and hence into the vehicle body.

The features of the object of this application as disclosed in the foregoing specification and claims and in the abstract and drawings may be essential to the realisation of the invention in its various embodiments either individually or in any desired combination.

i 1wp 1 1 7

Claims

1. Belt locking device for safety belts, more particularly in motor vehicles, comprising a self" locking belt reeling means and a clamping device, to be fixed to the vehicle, which causes locking of the belt, said clamping device having one fixed clamping jaw and one movable clamping jaw which enclose the belt between them, the belt reeling means in the locked position as a whole actuating the clamping device and being held in the rest position by a spring, wherein the belt reeling means and movable clamping jaw form a structural unit pivotable about a spindle fixed to a housing, and the effective lever arm (a) between the rotation spindle of the structural unit and the line of action of the spring which biases the structural unit into its rest position is smaller than the lever arm (b) effective between the rotation spindle and the point of exit of the belt from the belt reeling means.

2. Belt locking device as claimed in claim 1, wherein the point of exit of the belt from the belt reeling means is at a spacing from the clamping plane of the clamping device.

3. Belt locking device as claimed in claim 1 or 2, wherein the line of action of the spring runs parallel to the plane of the belt emerging from the structural unit.

4. Belt locking device as claimed in any of claims 1 to 3, wherein at both ends of the clamping jaws defined by the passage of the belt there is a fixed belt guide.

5. Belt locking device as claimed in claim 4, wherein the lower belt guide is constructed as an abutment for the structural unit in its springloaded rest position.

8

6. Belt locking device as claimed in any of claims 1 to 5, wherein in the clamping position of the structural unit the belt winding spindle of the belt reeling means can be arrested by means of an abutment in a housing fixable to the vehicle in the event of failure of the clamping action of the clamping means.

7. Belt locking device as claimed in any of claims 1 to 6, wherein the movable clamping jaw and/or the fixed clamping jaw has or have a lining and/or structure which increases friction.

8. Belt locking device as claimed in any of claims 1 to 7, wherein the belt winding spindle is supported in lateral plates which are attached to the sides of the movable clamping jaw as projections thereon.

9. Belt locking device substantially as hereinbefore described with reference to the accompanying drawings.

a Published 1989 at ThePatent Office, State House, 66,171 High Holborn, LondonWCIR4TP. Further copies maybe obtainedfrom The Patent Office. Sales Branch, St Mary Cray, Orpington, Kent BR-5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent, Con. 1187 v 1 0