EP0043239B1

EP0043239B1 - A tongue and buckle fastener for a safety belt

Info

Publication number: EP0043239B1
Application number: EP19810302860
Authority: EP
Inventors: Douglas James Cunningham; John Edward Mack
Original assignee: Britax Wingard Ltd
Current assignee: SMR Automotive Mirrors UK Ltd
Priority date: 1980-06-28
Filing date: 1981-06-25
Publication date: 1986-02-05
Also published as: EP0043239A1; DE3173708D1

Description

This invention relates to a tongue and buckle fastener for a safety belt comprising a tongue having a latching formation thereon, a buckle in which a passageway is provided for receiving the tongue, a spring-loaded tongue ejector which is slidable in the passageway, a latch member movable transversely of the passageway between a latching position in which it engages with the latching formation to retain the tongue in the passageway and a release position in which the tongue is displaceable by the ejector outwardly along the passageway from its retained position, the latch member being spring-biased into its latching position, a push button displaceable longitudinally of the passageway and operative when depressed to move the latch member to its release position, catch means for retaining the push button in its depressed position and release means on the ejector for releasing the catch means when the tongue has been inserted into the passageway to such an extent that the latching formation thereon has passed the latch member. A fastener of this type is disclosed in FR-A-2385350.
It is an object of the present invention to provide a tongue and buckle fastener of the foregoing type in which, during release of the fastener, the catch means is held out of engagement until the tongue has been ejected to a sufficient extent to prevent the latch member returning to its latched position.
The present invention provides a tongue and buckle fastener of this type in which the release means comprises a release member which is capable of limited longitudinal movement relative to the ejector so that the position of the ejector at which the release member frees the push button during insertion of the tongue is further from the end of the buckle from which the tongue is inserted than the position in which the release member allows the detent to enter the recess during ejection of the tongue.
Thus, during insertion, release of the push button is delayed until the latching formation of the tongue has passed the latch member. During release, the push button is not retained in its depressed position until the tongue has been ejected. sufficiently for the latch member to be unable to re-engage therewith.
Embodiments of the invention will now be described by way of example, with reference to the accompanying drawings, in which:

Figures 1 and 2 are longitudinal sectional views of a buckle in accordance with the invention, prior to insertion of the tongue, and at the intermediate stage during insertion respectively;
Figure 3 is a front elevation of the latch member of the buckle shown in Figures 1 and 2;
Figure 4 is a scrap plan view of the head of the tongue for use with the buckle shown in Figures 1 to 3;
Figure 5 is a longitudinal sectional view of the buckle shown in Figure 1 after insertion has been completed;
Figure 6 is a front elevation of the release member of the buckle shown in Figures 1 and 2; and
Figure 7 is a plan view of a wall member or plate of the buckle shown in Figures 1 and 2.

Referring to Figures 1 to 5, the fastener comprises a tongue 10 and a buckle 110. As can be seen in Figure 4, the tongue 10 has a head portion 14 with shoulders 16 and 18.
The buckle 110 comprises a housing 20 in which a push button 22 is slidably mounted for movement between the position shown in Figure 1 and the position shown in Figure 5, a spring 24 biasing it into the latter position. The housing 20 also contains a pair of spaced parallel plates 26 and 118 which define a passageway 30 for receiving the tongue 10. One or both of the plates 26 and 118 may have turned-down edge formations (not shown) to hold the two plates spaced apart at the required distance, as described in GB-A--2030205. The two plates 26 and 118 are attached by a rivet 32 to a member 34 by which the buckle 110 is secured to the vehicle in which the safety belt is to be used.
An ejector 112 has a transversely extending slot 113 in which is mounted a release member in the form of a rocker 114. Referring particularly to Figure 6, the rocker 114 is generally cruciform shape with a long limb projecting through a slot 44 in the plate 118. Opposite to the limb 116, the rocker 114 has a limb 120 which projects into a slot 42 in the plate 26 opposite to the slot 44. Side limbs 122 and 124 of the rocker 114 engage between the two plates 26 and 118 to retain the rocker in position. The width of the slot 113 is substantially greater than the thickness of the rocker 114 so as to permit pivotal movement of the latter on its limbs 122 and 124. The ejector 112 also has a formation at the end opposite to the end engaged by the tongue 10 which serves to locate the end of a coil spring 46 for biasing the ejector 112 towards the left, as viewed in Figures 1, 2 and 5, so as to tend to eject the tongue 10.
Referring to Figure 7, in addition to the longitudinal slot 44, the plate 118 has two transverse slots 128 and 129 and two further longitudinal slots 130 and 131, one on each side of the slot 44. Mounted on a transverse member 132, which forms an integral part of the push button 22, is a leaf spring 134 having an end portion 136 aligned to form a cam surface to cooperate with the limb 116 of the rocker 114, and two detents 138 aligned to be received in the slots 130 and 131 so as to retain the push button 22 in its depressed position, as shown in Fig. 1. A latch plate 48 is movable transversely of the passageway through the slots 128 and 129 and corresponding slots in the plate 26. Turning to Figure 3, the latch plate 48 is a bridge-like member having a pair of oppositely directed lateral shoulders 50 and 52 and a pair of downwardly directed feet 54 and 56. Each of the feet 54 and 56 is provided with a respective inwardly directed shoulder 58 and 60. The distance between the shoulders 58 and 60 is less than the width of the head 14 while the distance between the lower ends of the feet 54 and 56 is greater than the width. Thus, when the latch plate 48 is positioned so that the shoulders 58 and 60 are clear of the passageway 30, the tongue 10 can be freely inserted and removed while, when the latch plate 48 is moved into a position such that the shoulders 58 and 60 are aligned at the passageway 30, the tongue 10, if previously inserted, is retained in the buckle 110.
The push button 22 has a respective pair of ramps 62 and 140 for engagement with the lateral shoulders 50 and 52 on the latch plate 48. Thus, depression of the push button causes the ramps 62 to engage under the shoulders 50 and 52 to lift the latch plate 48 while the ramps 140 force the latch plate 48 into its latching position when the push button 22 is released. The upper ramps 140 are curved so as to allow a limited amount of lost motion between the push button 22 and the latch plate 48 when the push button 22 is in an intermediate position, while minimising this lost motion when the push button 22 is in its fully released position with the latch plate 48 engaged.
The operation of the buckle 110 is as follows. When the tongue 10 has been ejected, the buckle is as shown in Figure 1 with the detents 138 received in the slots 130 and 131 so as to hold the push button 22 in its depressed position. The latch plate 48 is held clear of the passageway 30 by the ramps 62 of the push button 22. The leaf spring 134 causes the rocker 114 to tilt as illustrated. When the tongue 10 is inserted, the head thereof engages with the ejector 112, displacing the latter against the spring 46 so that it moves into the position shown in Figure 2, the limb 116 of the rocker 114 having passed between the two detents 138 to engage with the end portion 136 of the leaf spring 134. The shoulders 16 and 18 of the tongue are now past the line of action of the latch plate 48 but the push button 22 is still held in its depressed position as the tilted orientation of the rocker 114 has not quite lifted the detents 138 out of the slots 130 and 131. Slight further insertion of the tongue 10 causes corresponding further movement of the ejector 112, the result of which is the complete disengagement of the detents 138 from the slots 130 and 131 to release the push button 22 whereupon it is urged by the spring 24 into the position shown in Figure 5, the detents 138 resting on the outer surface of the plate 118.
When the buckle is to be released, the push button 22 is depressed. When the end portion 136 engages with the rocker 114, it pushes the latter in the opposite direction to that illustrated in Figure 2. The effect of this is that the detents 138 are prevented from engaging in the slots 130 and 131 until after the shoulders 16 and 18 of the tongue 10 have moved to the left of the right-hand edge of the latch plate 48, as viewed in Figure 2, thereby preventing partial re-engagement of the latch plate with the push button in its depressed position.

Claims

1. A tongue and buckle fastener for a safety belt comprising a tongue (10) having a latching formation (16, 18) thereon and a buckle (110) in which a passageway (30) is provided for receiving the tongue (10), the buckle (110) having a spring-loaded tongue ejector (112) which is slidable in the passageway (30), a latch member (48) movable transversely of the passageway (30) between a latching position in which it engages with the latching formation (16, 18) to retain the tongue (10) in the passageway (30) and a release position in which the tongue (10) is displaceable by the ejector (112) outwardly along the passageway (30) from its retained position, the latch member (48) being spring-biased into its latching position, and a push button (22) displaceable longitudinally of the passageway (30) and operative when depressed to move the latch member (48) to its release position, catch means (134) for retaining the push button (22) in its depressed position and release means (114) movable by the ejector (112) for releasing the catch means (134) when the tongue (10) has been inserted in the passageway (30) to such an extent that the latching formation (16,18) thereon has passed the latch member (48) characterised in that the release means (114) has a release formation (116) which is capable of limited longitudinal movement relative to the ejector (112) so that the position of the ejector (112) at which the release means (114) frees the push button (22) during insertion of the tongue (10) is further from the. end of the buckle from which the tongue (10) is inserted than the position in which the release means (114) allows the detent (138) to enter the recess (130, 131) during ejection of the tongue (10).

2. A fastener according to claim 1, characterised in that the catch means comprises a spring-loaded catch member (134) attached to the push button (22) so that a detent (138) thereon is urged into engagement with a wall member (118) bounding one side of the passageway (30) so as to be received in a recess (130, 131) in the wall member (118) when the push button is in its depressed position, the release means comprises a release member (114) mounted on the ejector (112) and the release formation comprises an end (116) of the release member (114) which projects through a slot (44) in said wall member (118) into the path of said catch member (134) so as to cooperate therewith to move the detent (138) out of the recess (130, 131).

3. A fastener according to claim 1, characterised in that the release member (114) is pivotable relative to the ejector (112).