GB2104583A

GB2104583A - A buckle for safety belt systems

Info

Publication number: GB2104583A
Application number: GB08219048A
Authority: GB
Inventors: Harald Schmelow
Original assignee: SISPA SICHERUNGS SPANGENVERSCH
Current assignee: SISPA SICHERUNGS SPANGENVERSCH
Priority date: 1981-07-07
Filing date: 1982-07-01
Publication date: 1983-03-09
Also published as: GB2104583B; FR2509147A1; DE8119770U1; SE8204158L; SE8204158D0

Abstract

A buckle for safety belts comprises a locking element 1 which is to be connected to one belt end and surrounded by a housing 2 of plastics material, and a lock tongue 4 which is to be connected to the other belt end. The lock tongue 4 is insertable by its end into the locking element 1, in order to be locked therewithin by means of a locking member 6 kept under spring preloading, this locking action being neutralisable by depressing a release key 3 acting on the locking member 6. For structural simplification of the lock, the release key 3 is produced integrally in the form of a tongue with the plastics material housing surrounding the locking element 1 and is resiliently deflectable under application of pressure in the direction towards the locking member 6. <IMAGE>

Description

SPECIFICATION A buckle for safety belt systems The invention relates to buckles for safety belt systems of the kind comprising a locking element which is to be connected to one end of the belt and surrounded by a housing of plastics material, and a lock tongue which is to be connected to another belt and, which lock tongue is insertable by its end into the locking element in order to be locked therewithin by a locking member kept under spring preloading, this locking action being neutralisable by depressing a release key acting on the locking member. Hereinafter such a buckle will be referred to as "of the kind described".

The known plastics material housings for such buckles comprise a recess of larger size for a release key for actuation of the lock locking member. The release key is produced separately and inserted into the recess, in such manner that it cannot drop out. This form of constructions of the housing having a separate release key, has different disadvantages.

On the one hand, production is comparatively costly since separate injection moulding moulds are needed for the housing as well as for the release key. Furthermore, a return spring must be provided for the release key to restore the key into its initial position. An appropriate job time must also be taken into consideration for installing the key and its return spring, which must be associated as being comparatively sizeable, since this is a mass-production article. Since, finally, skewing or jamming of the release key must be prevented for reasons of operational safety, the freedom of movement between the key and the recess therefor must be of sufficiently large dimensions within the housing, which however implies the risk of soiling which for its part may impair the troublefree operation.

It is an object of the invention to provide a belt buckle of the kind described which can be manufactured more simply and inexpensively than hitherto whilst still being reliable in operation.

Accordingly the invention consists in a belt buckle of the kind described, wherein the release key is in the form of a tongue or projection made as a unit with the housing surrounding the locking element, and is resiliently deflectable under application of pressure in the direction towards the locking member.

A substantial reduction in production cost is possible with this construction, since only a single injection mould is required, the configuration of which encompasses the forming of the housing and the simultaneous integral forming of the release key which is thus produced as an integral part. Any plastics material having adequate remanent elasticity can be used for the housing and release key whereby a conventional return spring may be omitted, and its installation cost saved. A simplified assembling operation is also provided by the elimination of the separate release key. The risk of soiling the lock components is lessened, since the release key now formed in unit is installed in a close fit in its housing recess.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings which show one embodiment thereof by way of example only and in which: Figure 1 shows a longitudinal cross-section through the housing, the belt buckle being in the closed position, and Figure 2 shows a plan view of the belt buckle housing, the lock tongue not being illustrated however.

Referring now to the drawings, according to Figure 1, the belt buckle illustrated comprises a locking element 1 which is secured within a housing 2 of plastics material comprising a release key 3, a lock tongue 4 insertable into the locking element from the one narrow side, an ejector plate 5 for the lock tongue which is mounted in the locking element in longitudinally displaceable manner, a pivot bolt 6 oF angularly serpentine form acting as a locking member, one end of which is pivotable close to the belt side narrow side of the locking element around an axis situated in its plane, and the other end of which member engages in the lock tongue 4, and a leaf spring 7 acting as a return spring which for its part bears on the locking element 1 and on the other hand bears in slidable contact against the underside of the pivot bolt 6, so that the latter is normally held in the closed position. The lock tongue 4 is formed by a metal plate and is provided at the belt side with a plastics material covering 8 adapted to the housing 2, to which is joined the conventional belt (not shown). In the closed position according to Figure 1, the front edge 4a of the tongue 4 bears against a confronting edge area 5a of the ejector plate 5, the plate 5 on the other hand bearing against a spring 10 and the bolt 6, and the spring 10 on the other hand also bearing on the bolt 6.

The bolt 6 extends in the longitudinal direction of the lock and is made by bending a suitable metal strip and, for its pivotal mounting, has a bearing lug 11 at each side, the two bearing lugs being situated between mutually spaced lock plates 12, 13 of the locking element 1. The terminal section of the bolt 6, situated at the insertion side, is produced in hook form and engages in an excision 4b of the lock tongue 4.

The release key 3 is in the form of a tongue and is injection moulded in unit with the plastics material housing 2 the upper side of the housing being provided with a narrow U-shaped slot 1 4.

The material of the housing 1 has the required remanent elasticity, so that the tongue-like release key is reset automatically by inherent spring action. When downward pressure is exerted on the release key in the position shown in Figure 1, it is deflected downwards towards the locking member 6 and disengages the same from the lock tongue 4 under continued pressure. The lock tongue is then ejected from the locking element 1 by the ejector spring 1 0. Upon being freed, the integral release key 3 springs back into its initial position.

To avoid the risk of breakage of the tongue-like release key 3, the terminal areas 1 5 at the joined end of the key may be given a rounded form. The plastics material utilised for the housing 2 inclusive of the tongue 3 is advantageously a copolymerisate which may be a low-pressure or a high-pressure polyethylene.

Claims

1. A belt buckle for safety belt systems of the kind described wherein the release key is in the form of a tongue or projection made as a unit with the housing surrounding the locking element, and is resiliently deflectable under application of pressure in the direction towards the locking member.

2. A belt buckle substantially as hereinbefore described with reference to the accompanying drawings.

3. A safety belt system whenever including a belt buckle as claimed in either of the preceding claims.