Seat belt buckle

Information

  • Patent Grant
  • 5210915
  • Patent Number
    5,210,915
  • Date Filed
    Tuesday, September 29, 1992
    32 years ago
  • Date Issued
    Tuesday, May 18, 1993
    31 years ago
Abstract
A seat belt buckle adapted to releasably engage a latch plate 42 having an aperture 40 therein, the 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 the side walls, the 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, the locking member carrying a downwardly projecting locking element 38 engageable in the aperture 40 in the latch plate 42 to retain the latch plate in place and passing into the opening, a slider 44 slidable longitudinally of the locking member between a first position in which it is located under the 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 the locking member and engaging in the side walls to pivotally and resiliently mount the locking member for movement between its upper and lower positions and a pair of arms 34 extending laterally along the member, the pair of arms engaging abutments on the rigid frame to prevent flexing of the wings beyond their elastic limit.
Description
Claims
  • 1. In 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, upper edges of said side walls, 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, a downwardly projecting locking element on said locking member engageable in said opening in the latch plate effective to retain the latch plate in place and passing into said opening, the locking element, in the lower latching position of the locking member, having its forward edge spaced from the rearward edge of said opening by a given distance under normal conditions, a slider 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 is resiliently engaged against the rear of the bar to retain the locking member in its upper unlatched position, a push button positioned to push the slider from its first position to its second position, a slider spring positioned to urge the slider towards its first position and, 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 said wings being capable of elastic flexing, upon axial loading of said locking member by said latch plate, the improvement consisting of abutments on said rigid frame, and a pair of arms extending laterally from said member, said a pair of arms engaging, at least in the lower position of the latching member, said abutments on said rigid frame to prevent flexing of said wings beyond their elastic limit, and said pair of arms having their forward edges spaced from their associated abutment by a spacing less than said given distance, whereby the load bearing capacity of said pair of arms and their associated abutment are enhanced by engagement of the forward edge of the locking element with the rearward edge of the opening.
  • 2. A buckle according to claim 1, wherein said pair of arms extend laterally from said latching member at a location between said wings and said opening.
  • 3. A buckle according to claim 1, wherein said laterally extending arms are shorter than said laterally extending wings.
  • 4. A buckle according to claim 3, wherein said abutments are in a form of notches in the upper edges of said side walls.
  • 5. A buckle according to claim 1, wherein 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.
Priority Claims (2)
Number Date Country Kind
8925036 Nov 1989 GBX
PCT/GB90/01681 Nov 1990 WOX
BACKGROUND TO THE INVENTION

The present invention is a continuation-in-part of prior U.S. patent application Ser. No. 07/687890 filed Sep, 3, 1991, abandoned as filed under the Patent Cooperation Treaty with an effective filing date of Nov. 2, 1990 and entitled "Seat Belt Buckle". The present invention relates to an improved seat buckle for seat belts in motor vehicles. Prior art seat belt buckle assemblies involve a latch plate having an aperture therein, said latch plate being attached to one part of the seat belt itself 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. A releasable locking member engages in the aperture in the latch plate and in the opening in the frame to releasably retain the latch plate. U.S. Pat. No. 4,899,424 discloses a particular form of such a buckle assembly having 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, a downwardly projecting locking element on said locking member engageable in said aperture in the latch plate effective to retain the latch plate in place and passing into said opening, the locking element, in the lower latching position of the locking member, having its forward edge spaced from the rearward edge of said opening by a given distance under normal conditions, a slider 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 is resiliently engaged against the rear of the bar to retain the locking member in its upper unlatched position, a push button positioned to push the slider from its first position to its second position, a slider spring positioned to urge the slider towards its first position, 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, said wings being capable of elastic flexing, upon axial loading of said locking member by said latch plate. The latch plate can be inserted against the action of the spring loaded ejector and when in the fully inserted position the locking member is pivoted to a lower latching position in which the 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. For a seat belt buckle to operate satisfactorily, it must be capable of being comfortably worn in a latched condition and readily be releasible when the user wishes to leave the vehicle. The user must be protected from vehicle accidents and from secondary accidents by the seat belt. The buckle therefore must not be capable of releasing the latch plate during an accident or as a result of an impact of an accident. For a seat belt to operate satisfactorily, it must be capable of releasing the latch plate from the buckle easily in order that the driver or passenger may get out of the vehicle immediately. This is the purpose of the structure of U.S. Pat. No. 4,899,424. In that patent the condition in which the latch plate latches to the locking bar of the locking element, that is to say the normal wearing condition of the seat belt, is the condition in which the belt can take the load of the driver moving forwardly during an accident situation. The latch plate takes large loads in a forward direction and the buckle itself takes large loads in the rearward direction, so that the lock bar of the locking member takes the loads in the forward direction imparted by the latch plate and the latch plate is prevented from releasing from the buckle by the forward edge of the lock bar and the forward edge of the base plate aperture contacting and withstanding the large loads. Now, after an accident has occurred, when the loads are no longer applied, the forward edge of the lock bar remains in contact with the forward edge of the aperture in the base plate. Therefore, the locking member cannot rotate and the latch plate cannot be released readily from the buckle by the occupant or a rescuer. The pair of wings extend laterally from the locking member and engage in the side walls of the frame to pivotally and resiliently mount the locking member from movement between its upper and lower positions, the wings being capable of flexing. To operate satisfactorily within its own limitations, the buckle of U.S. Pat. No. 4,899,424 makes possible pivoting of the locking member using the flexibility of the wings. However, with this structure the applied loads are taken, not only by both the forward edge, but also by the locking member which tends to rotate downwardly, and in this case the wing portions deform not elastically but plastically and eventually the lock bar of the locking member is then unable to return to the initial position and this can cause a problem of release of the buckle after an accident. It is an object of the present invention to overcome such problems. According to the invention, these problems are overcome by providing a pair of arms extending laterally from the locking member, the pair of arms engaging at least in the lower position of the latching member, the abutments on the rigid frame to prevent flexing of the wings beyond their elastic limit and by said pair of arms having their forward edges spaced from their associated abutment by spacing less than the distance by which the forward edge of the locking member is spaced from the rearward edge of the opening under normal conditions, whereby the load bearing capacity of said pair of arms and their associated abutment are enhanced by engagement of the forward edge of the locking member with the rearward edge of the opening. With such a structure, the clearance between the upper arms and the base plate is designed in order to keep the deformation of the wings within their elastic limit, thereby to enable, even after an accident situation, the buckle to be released. In a preferred construction, the pair of arms extend laterally from the latching member at a location between the wings and said opening and, advantageously, said laterally extending arms are shorter than said laterally extending wings so that the wings can deform elastically more readily than the arms which therefore act as stop members.

US Referenced Citations (6)
Number Name Date Kind
4064603 Romanzi, Jr. Dec 1977
4388746 Krantz et al. Jun 1983
4451958 Robben et al. Jun 1984
4550474 Doty et al. Nov 1985
4899424 Barnes et al. Feb 1990
4928366 Ballet May 1990
Foreign Referenced Citations (3)
Number Date Country
114332 Aug 1984 EPX
2010955 Jul 1979 GBX
1580726 Dec 1980 GBX
Continuation in Parts (1)
Number Date Country
Parent 687890 Sep 1991