EP0452464B1

EP0452464B1 - Seat belt buckle

Info

Publication number: EP0452464B1
Application number: EP19900916769
Authority: EP
Inventors: Ron Clarke
Original assignee: European Components Co Ltd
Current assignee: European Components Co Ltd
Priority date: 1989-11-06
Filing date: 1990-11-02
Publication date: 1994-02-16
Anticipated expiration: 2010-11-02
Also published as: ES2051523T3; DE69006720D1; JPH04506922A; EP0452464A1; GB8925036D0; JPH07112443B2; DE69006720T2; GB2238074A; WO1991006231A1

Abstract

A seat belt buckle adapted to releasably engage a latch plate (42) having an aperture (40) therein, said buckle comprising a rigid frame (10) including a base (12) having an opening therein, upstanding side walls (14) adapted to guide the latch plate longitudinally of the frame, a bar (16) extending transversely of the frame between said side walls, said bar being spaced above the base, a locking member (24) pivotally mounted on the frame and pivotal between a lower latched position and an upper unlatched position, said locking member carrying a downwardly projecting locking element (38) engageable in said aperture (40) in the latch plate (42) to retain the latch plate in place and passing into said opening, a slider (44) slidable longitudinally of the locking member between a first position in which it is located under said bar (16), to retain the locking member in the lower latched position and a second position in which it is resiliently engaged against the rear of the bar to retain the locking member in its upper unlatched position, a push button (52) to push the slider from its first position to its second position, a slider spring (48) to urge the slider towards its first position, a pair of wings (30) extending laterally from said locking member and engaging in said side walls to pivotally and resiliently mount the locking member for movement between its upper and lower positions and at least one stop member (34) extending laterally along said member, said at least one stop member engaging abutments on said rigid frame to prevent flexing of said wings beyond their elastic limit.

Description

The present invention relates to seat belt buckles for seat belts in motor vehicles. One form of such seat belt buckle involves a latch plate having an aperture therein, engageable on one part of the seat belt, and a buckle having a rigid frame including a base having an opening therein and upstanding side walls adapted to guide the latch plate longitudinally of the frame.
The latch plate can be inserted against the action of a spring loaded ejector and when in the fully inserted position a locking member is pivoted to a lower latching position in which a locking element engages in the aperture in the latch plate. A push button is used to release the locking member which pivots back to an unlatched position.
GB-2010955 discloses a seat belt buckle adapted to releasably engage a latch plate having an aperture therein, said buckle comprising a rigid frame including a base having an opening therein, upstanding side walls adapted to guide the latch plate longitudinally of the frame, a bar extending transversely of the frame between said side walls, said bar being spaced above the base, a locking member pivotally mounted on the frame and pivotal between a lower latched position and an upper unlatched position, said locking member carrying a downwardly projecting locking element engageable in said aperture in the latch plate to retain the latch plate in place and passing into said opening, a pair of wings extending laterally from said locking member and engaging in said side walls to pivotally and resiliently mount the locking member for movement between its upper and lower positions.
It is important that such seat belt buckles should have an easy and effective latching of the latch plate and should easily release the latch plate by operation of the push button. It is most important to retain the latch plate in a latch position in the buckle even when the latch plate and buckle are subject to a very heavy impact load.
The present invention is characterised in that a slider is slidable longitudinally of the locking member between a first position in which it is located under said bar, to retain the locking member in the lower latched position and a second position in which it allows said locking member to pivot to its upper unlatched position, in that a slider spring urges the slider towards its first position; in that a push button is provided to push the slider to its second position, in that said slider is resiliently engaged by said slider spring against the rear of said bar to retain the locking member in its upper unlatched position, in that said wings are capable of elastic flexing, upon axial loading of said locking member by said latch plate, and in that at least one stop member extends laterally from said member, said at least one stop member engaging abutments on said rigid frame to prevent flexing of said wings beyond their elastic limit.
The provision of the bar extending over the slider assists in the withstanding of heavy loads and prevents inadvertent release of the buckle. More importantly, however, the provision of the stop member or members prevents excessive flexing of the wings, which acts as the pivot for the locking member, so that the wings never are distorted beyond their elastic limit.
The stop member may take a number of forms but advantageously each stop member extends laterally from the locking member forwardly from the wings and may comprise a pair of arms engaging, at least in the lower latching position of the locking member, against abutments in the side walls. In a simple construction these abutments are in the form of open-topped notches in the upper edges of the side walls into which the arms move in the lower latching position.
Preferably the locking element in the lower latching position of the locking member, has its forward edge spaced from the forward edge of said opening by a given distance under normal conditions. Desirably said at least one stop member has its forward edge spaced from its associated abutment by a spacing less than said given distance, whereby the load bearing capacity of the or each stop member and its associated abutment are enhanced by engagement of the forward edge of the locking element with the rearward edge of the opening. Advantageously the rearward edge of said bar and the forward edge of said slider are cooperatingly chamfered to retain the locking member in its upper unlatched position when said forward and rearward edges are inter-engaged by said slider spring.
In order that the present invention may more readily be understood, the following description is given, merely by way of example, reference being made to the accompanying drawings in which:-

Figure 1 is a side elevation of one embodiment of buckle according to the invention shown in the latched position;
Figure 2 is a similar view in section in the unlatched position; and
Figure 3 is a plan view, half in section, of the buckle illustrated in Figures 1 and 2.

Referring first to Figure 1 the buckle includes a rigid frame 10 having a base plate 12 having two upstanding side walls 14 extending from each side edge thereof. A bar 16 extends between the side walls 14 and is spaced from and parallel to the base plate 12. An opening 20 is formed in the base plate 12 and is provided with a front edge 22 (Figure 2).
Pivotally mounted between the side walls 14 is a locking member 24, which includes a forwardly extending body 26 and downwardly extending legs 28. The body is provided with two laterally extending wings 30 engaging in rear notches 32 in the side walls 14. Extending parallel to these wings 30 are arms 34 which can, in the lower latched position as illustrated in Figure 1, engage in forward notches 36 in the side wall.
At the forward end of the body 26 of the locking member is a locking element 38 which, in the latched position, passes through an aperture 40 in a latch plate 42 to retain the latch plate in place. It will be noted that longitudinally slidable on the locking member 24 is a slider 44 having a chamfered leading edge 46. The slider is urged towards the front (the left in the Figures) by a slider spring 48 engaged over a projection 50 on the body 26 of the locking member 24.
Longitudinally slidable on the side walls 14 is a push button 52 which has rearward projections 54 engaging forward projections 56 on an ejector 58 longitudinally slidable in the opening 20 in the base plate 12, and urged to the forward position by an ejector spring 60.
In use, starting from the position illustrated in Figure 2, a latch plate 42 is inserted in the guide channel formed by the base plate 12 and the side walls 14, it causes the ejector 58 to move rearwardly, that is to the right, against the action of its spring 60. This movement continues until the ejector is moved so far rearwards that it engages on the bottom of the leg 28 of the locking member 24. The resulting couple rotates the locking member/slider system causing the slider 44 to move down and return under the bar 16 to the position illustrated in Figure 1. When the plate 42 is unloaded, the aperture 40 therein abuts the locking element 38 which retains the latch plate 42 in place so that the buckle cannot unlatch.
In this condition, if an accident or the like occurs, and a very great strain is put on the buckle, then the latch plate 42 will be urged forward and will move with it the locking element 38, thereby closing the gap 64 illustrated in Figure 2, so that the front face of the locking element 38 abuts the front face 22 of the aperture 20. During this movement, the wings 30 will flex rearwards but the arms 34 engaging the front of the notches 36 will prevent anything more than a limited flexing so that the wings are not stressed beyond their elastic limit.
With the reduction of load (after impact) both the wings and the main body of the locking member recover elastically to restore the clearances 64, 66 (Figure 3) between the locking member 34 and the frame sufficient to allow the front face 70 of the locking element 38 to sweep past the frame edge 22, when the locking member is released to the unlatched position and in particular with the release preformed whilst specific test loads are being applied longitudinally through the latch plate.

Claims

A seat belt buckle adapted to releasably engage a latch plate (42) having an aperture (40) therein, said buckle comprising a rigid frame (10) including a base (12) having an opening (20) therein, upstanding side walls (14) adapted to guide the latch plate longitudinally of the frame, a bar (16) extending transversely of the frame between said side walls, said bar being spaced above the base, a locking member (24) pivotally mounted on the frame and pivotal between a lower latched position and an upper unlatched position, said locking member (24) carrying a downwardly projecting locking element (38) engageable in said aperture (40) in the latch plate (42) to retain the latch plate in place and passing into said opening (20), a pair of wings (30) extending laterally from said locking member and engaging in said side walls to pivotally and resiliently mount the locking member for movement between its upper and lower positions, characterised in that a slider (44) is slidable longitudinally of the locking member between a first position in which it is located under said bar (16), to retain the locking member in the lower latched position and a second position in which it allows said locking member to pivot to its upper unlatched position, in that a slider spring 48 urges the slider towards its first position, in that a push button (52) is provided to push the slider to its second position, in that said slider is resiliently engaged by said slider spring against the rear of said bar to retain the locking member in its upper unlatched position, in that said wings (30) are capable of elastic flexing, upon axial loading of said locking member by said latch plate (42), and in that at least one stop member (34) extends laterally from said member, said at least one stop member engaging abutments (36) on said rigid frame to prevent flexing of said wings beyond their elastic limit.
A seat belt buckle according to claim 1, characterised in that at least one stop member (34) extends laterally from said latching member forwardly of said wings (30).
A seat belt buckle according to claim 2, characterised in that at least one stop member (34) comprises a pair of arms engaging, at least in the lower position of the latching member, against said abutments (36) which are provided in said side wall.
A seat belt buckle according to claim 3, characterised in that abutments (36) are in a form of notches in the upper edges of said side walls.
A seat belt buckle according to any preceding claim, wherein the locking element (38), in the lower latching position of the locking member, has its forward edge spaced from the forward edge of said opening (20) by a given distance under normal conditions.
A seat belt buckle according to claim 5, characterised in that at least one stop member (34) has its forward edge spaced from its associated abutment (36) by a spacing less than said given distance, whereby the load bearing capacity of the or each stop member (34) and its associated abutment (36) are enhanced by engagement of the forward edge of the locking element (38) with the rearward edge of the opening (20).
A seat belt buckle according to any preceding claim, wherein the rearward edge (18) of said bar (16) and the forward edge (46) of said slider (44) are co-operatingly chamfered to retain the locking member in its upper unlatched position when said forward and rearward edges are inter-engaged by said slider spring.