Seatbelt Buckle

Abstract

A pivotally mounted cover lever for a seatbelt buckle is biased to a closed position and held against rattling by a first leaf of a spring body which also has a second leaf urging a latching dog to its latching position.

Description

This invention relates to a safety belt buckle and more particularly to a safety belt buckle of the lever-operated kind for releasably fastening together the ends of seatbelts used in automobiles, airplanes or the like.

In a lever-operated seatbelt buckle, the lever is usually pivotally mounted at one end on a buckle base and extends longitudinally of the base to serve as a cover for the base. The cover lever is biased to a closed position by a spring or springs which also bias a pivotally mounted latch member having a latching surface, usually in the form of a latch dog, to project into a latch opening in a tongue plate. The tongue plate is fastened to one end of the seatbelt and is latched by the dog to the buckle base, the buckle base being fastened to the other end of the belt. To release the tongue plate for withdrawal, the cover lever is pivoted relative to the base to actuate the latch member to withdraw the latch dog from the latch opening in the tongue plate, releasing the tongue plate for disengagement.

When such seatbelt buckles are manufactured for mass use in automobiles, small reductions in the cost of individual elements constituting the buckle and reductions in assembly costs can result in large money savings. One example of an assembly cost for many of the conventional lever-operated buckles is the cost of assembling springs on pivot pins during a part of the assembly operation for the buckles. The buckle of the present invention eliminates certain complications and costs of assembly with a novel form of a spring body which may be readily formed from a piece of flexible material, such as spring steel, in a low-cost stamping operation. The spring body advantageously performs a number of functions and permits a relatively wide range of tolerances for the dimensional relationships between the cover lever and the latch member, so that they need not be held to close tolerances which would otherwise add significantly to the cost.

Accordingly, a general object of the invention is to provide an improved seatbelt buckle of the foregoing kind.

Other objects and advantages of the invention will become apparent from the detailed description taken in connection with the accompanying drawings in which:

FIG. 1 is a perspective view of a seatbelt buckle embodying the features of the present invention;

FIG. 2 is an enlarged top sectional view taken just under the top of the cover lever;

FIG. 3 is a longitudinal sectional view taken along the line 3-3 of FIG. 2;

FIG. 4 is an exploded perspective view of the seatbelt buckle of FIG. 1; and

FIG. 5 is an enlarged, fragmentary view taken substantially along the line 5-5 of FIG. 4.

As shown in the drawings for purposes of illustration, the invention is embodied, very generally, in a safety belt buckle 11 which is attached to one end of a seatbelt 13 and receives a removable tongue plate 15 fastened to another end of the belt. To fasten these belt ends together, the tongue plate is inserted into a slot 17 between a cover lever 19 and a buckle base 21 and then projected interiorally of the buckle to bring a latch opening 23 in the tongue plate into alignment with a latch dog 25 (FIG. 3) carried on a pivotally mounted latch member 27. The latch member is biased to project the latch dog 25 in the latch opening 23 and, as will be explained in detail, the cover lever 19 is biased to and at a closed position (FIGS. 1 and 3) in which the cover is disposed adjacent to and substantially parallel with the buckle base. To pivot the latch member 27 to release position in which the latch dog 25 is withdrawn from the latch opening 23 of the tongue plate 15, the free end 31 of the cover lever 19 is grasped and pivoted away from the base to abut a rear, narrow portion 33 (FIG. 3) of the cover lever against rear edge portions 34 of the latch member 27 and pivot the latch dog 25 to its release position, as will be explained below in greater detail.

In accordance with the present invention, the safety belt buckle includes a novel spring body 29 (FIG. 4) which is readily formed and assembled in the buckle and which permits a wide range of dimensional tolerances for the cover lever 19 and latch dog 27. Preferably, the spring body 29 is formed from a single sheet of spring steel with at least one leaf spring 35 for biasing the latching member 27 to its latching position and a second leaf spring 37 for holding the cover lever 19 against rattling or loose movement in its closed position. As will be explained in greater detail, the cover lever 19 and latch member 27 are separated from each other by a gap the size of which may vary considerably with variations from the nominal dimension for the parts, and the separate leaf springs 35 and 37 function independently of one another to assure that each moves to its respective latching and closed positions despite any variations from nominal dimensions. Also, as will be explained in greater detail, the spring body 29 functions as a stop to limit pivoting of the latch member 27 at its release position and the cover lever 19 at its open position.

Proceeding now with a more detailed description of the individual elements of the seatbelt buckle 11, the buckle base 21 is in the form of a channel defined by a pair of upstanding flanges 39 extending longitudinally along and generally perpendicular to a central baseplate 41 disposed between the flanges. At one end of the buckle base, the flanges define a portion of the tongue entry slot 17 and are spaced relatively close together as compared to the spacing between the flanges at the opposite end of the base. From the narrow end, the flanges 39 diverge outwardly along inclined sections 43 (FIG. 4) to parallel end sections 45. This construction of the buckle base permits a reduction in size and weight for the buckle, tongue plate 15 and cover lever 19. Also, the making of the ends of the buckle base of significantly different widths facilitates an understanding by the wearer that the tongue plate 15 should fit into the narrower end of the buckle base rather than into the wide end of the buckle base. With some prior art buckles, the wearer has inserted the tongue plate into the wrong end of the buckle and then has assumed that the buckle was fastened when, in fact, it was not.

To facilitate attachment of the belt 13 to the buckle base 21, a belt opening 47 (FIGS. 3 and 4) is formed in the baseplate 41 to admit a loop 49 of the belt which is disposed about a knurled rod 51 extending transversely between the side flanges 39. A portion of the baseplate 41 at the belt opening 47 is bent upwardly at an acute angle to form an upstanding lip 53 adjacent the knurled rod 51. From the side flanges inwardly directed tabs 55 (FIGS. 2 and 3) are struck towards one another to abut the ends of the lip 53 and serve as stops for holding the lip against bending with a force exerted thereon from the knurled rod. Elongated slots 57 are formed in the side flanges and are inclined downwardly and toward the lip and receive flattened ends 59 (FIG. 4) on the knurled rod, these flattened ends being freely slideable in the slots. Exertion of tension force on the belt loop 49 slides the rod 51 towards the lip 53 and grasps the belt in the nip between them. When it is desired to adjust the size of the belt, the belt tension is relaxed, and the rod is removed away from the lip, whereupon the belt can be slid about the rod to an adjusted position.

The cover lever 19 is preferably formed by molding a plastic material to provide a cover which is light in weight, as compared to a metal cover, and inexpensive to manufacture. The cover is formed with a top wall 61 which spans the side flanges 39 of the buckle base 21 and has integral depending sidewalls 63 which are disposed outwardly of and generally parallel to the respective sections of the side flanges 39. The free end 31 of the cover lever defines an opening 65 (FIG. 3) with the buckle base 21 into which the finger tips of the wearer may be inserted to grasp and then pivot the free end 31 away, i.e., upwardly, from the buckle base. In this instance, finger tips may be inserted about 0.4 inch and then they will abut a blocking wall 67 (FIG. 3) which depends from the inner side of the top cover wall 61 to adjacent the baseplate 41. This blocking wall extends transversely of the side flanges 39 of the buckle base and precludes an insertion of the tongue plate 15 into the wide end of the buckle to the extent that the wearer would think that the tongue plate was in position for latching. Also, because of the considerable difference between the width of the tongue plate 15 and the spacing between the side flange sections 45 of the buckle base 41, the wearer will not normally attempt a tongue plate insertion at this wider end of the buckle.

At the narrow rear end 33 of the cover lever 19, a depending end wall 69 extends toward the base but is spaced therefrom to define the upper wall of the entry slot 17 for the tongue plate 15. This end wall 69 prevents an insertion of the tongue upwardly into the spring body 29 over or over the latching member 27 and thereby prevents a false latching condition. As will be explained in detail, this end wall 69 has on its inner side an internal groove 71 (FIGS. 3 and 5) in the top cover wall 61 into which projects a free end 73 of the leaf spring 37 which biases the cover lever to its closed position and exerts a force holding the cover and the web supporting rod 51 against rattling. Adjacent the spring receiving groove 71 is formed a pair of abutments or pads 75 on the interior of the cover end wall 69 for swinging into engagement with the edge portions 34 of the latching member 27 and pivoting the latter to its release position.

The cover lever 19 is provided with means to abut the belt loop 49 on the rod 51 and to hold its flattened rod ends 59 against the lower edges of the elongated slots thereby holding the rod ends against rattling. More specifically, the spring body 29 biases the cover lever 19 to its closed position at which abutments or bosses 77 (FIGS. 3 and 4) integrally formed on the inner side of the top cover wall 61 abut the top of the belt loop 49 and bias its supporting rod 51 to engage its flat ends 59 against the lower wall of the elongated slots 57. Since the cover lever is biased against the belt 49, it is likewise held against its rattling on the top of the base flanges 39.

For this purpose of pivotally mounting the cover lever 19 on the buckle base 21, there is provided a pivot pin 79 which extends transversely of and projects through aligned openings 81 (FIG. 4) in the base side flanges 39 and into aligned openings 83 in the cover sidewalls 63. The pivot pin is disposed substantially parallel to the buckle base 41 and is spaced above the base to allow insertion of the tongue plate 15 between it and the buckle base. In this instance, the pivot pin is formed with an enlarged head 85 at one end which fits in a circular recess about the opening 83 in the sidewall 63 of the cover lever. At its other end, the pivot pin has a central, axially extending bore 87 to receive a shaft 89 (FIG. 4) of a locking pin 91 which also has an enlarged head fitted into a recess about the other circular opening 83 in the opposite sidewall of the cover lever. The locking pin shaft 89 is driven into the bore and has a tight, forced fit therewith, preventing its separation under normal usage.

For the purpose of pivotally mounting the latching member 27 on the pivot pin 79 for movement toward or from its release and latching positions, the latching member is formed with a pair of trunnion arms 93 (FIGS. 2 and 4) disposed on opposite sides of a central plate 95 and extending laterally from the plate. Openings 97 in the trunnion arms receive the pivot pin 79 and, in this manner, the latching member 27 is pivotally mounted to swing about the axis of the pivot pin 79.

The central plate 95 of the latching member 27 extends inwardly from its pivot axis to an edge 99 from which is depressed the latching dog 25. The dog is formed, in this instance, by a stamping operation which strikes a centrally located, downwardly inclined wall 101 to project beneath the plane defined by the underside of the central plate 95. When the latch dog 25 is in its latching position (FIG. 3), the dog 25 is positioned to project into the latch opening 23 with a leading edge 103 (FIG. 3) on the dog 25 abutting an abutment wall 105 (FIG. 1) defining a side of the latch opening 23 in the tongue plate 15. With the dog 25 in latch opening 23, the underside of the free edge 99 of the latch member 27 abuts the top of the tongue plate on opposite sides of the dog 25 and holds the tongue plate against the base plate 41 to prevent the tongue plate from rattling on the baseplate.

The latch member 27 pivots in response to an opening movement of the cover lever 19, as abutment pads 75 on the latch member move into engagement with the portions 34 of the latch member 27 which are disposed on the other side of the pivot pin 79 from the latch dog 25. In this instance, latch member has a pair of upwardly turned fingers or portions 107 which (FIGS. 3 and 4) are formed integrally with the central plate 95 on the end of the plate opposite the latching dog 25. The edge portions 34 are at the ends of the fingers 107. Between the fingers 107 and the trunnion arms 93 are formed slots 109 (FIG. 2) with large radius fillets 111 to afford strain relief during the formation of the latching member by an inexpensive punching and stamping operation. The fingers 107 are spaced from one another by a central slot 112 which is aligned with the leaf spring 37 to allow clearance between the leaf spring and the latching member 27, as will be explained in greater detail. With the latching dog 25 abutting the buckle base 41 (as in FIG. 3), the central plate 95 of the latching member 27 is disposed in a plane substantially parallel to the buckle base 41. The fingers 107 curve upwardly from this plane to the rear edge portions 34 located adjacent but spaced from the cover abutments 75, which are disposed slightly above a horizontal plane through the axis of the pivot pin 79.

The abutment pads 75 are aligned with but spaced from the ends 34 of the fingers 107 by a gap 113 (FIG. 3) which may be narrowed or enlarged, within a fairly wide range, as determined by the tolerances for the respective cover lever 19 and latch member 27 without noticeably affecting the assembly or operation of the buckle.

For the purpose of biasing the latching member 27 to its latching position, the leaf springs 35 are attached to the spring body 29 at and extend downwardly from a central web 115 which is disposed generally parallel to the top cover lever wall 61 when the latter is in the closed position. The springs 35 are bent arcuately from this web 115 with downwardly opening arcs to their lower free ends 117 which are curled and abutted against the top of the central plate 95 of the latching member 27 and bias it toward its latching position. To prevent their breaking, the leaf springs 35 have an increasing width from their free ends to the central web 115 in a manner to distribute the flexing load relatively uniformly throughout the spring. Also, large radius, strain relieving fillets 119 are provided at the junction of the leaves 35 with the central web. A downturned flange 121 (FIGS. 2 and 3) on an edge of the web 115 adds rigidity to the spring body.

For the purpose of holding the cover lever 19 against rattling while in its closed position, the leaf 37 of the spring body 29 extends from said web 115 at one side of the pivot axis to engage said cover lever 19 at a point on the other side of the pivot axis. More specifically, the leaf 37 is formed with a first downwardly opening, arcuate bend 125 to extend beneath the pivot pin 79 and with an upwardly extending bend 127 to fit about the pivot pin. The free end 73 of the spring 37 projects upwardly into groove or slot 71 formed in the cover lever 19 intermediate the abutment pads 75. To prevent the free end 73 of the spring from digging into the plastic cover, the free end is bent into a curl to provide a curved surface at the point of engagement with the cover lever. The spring 37 is flexed when it is forced down by the cover lever as it is mounted on the pivot pin 79 during assembly of the buckle, and is further flexed as the cover is opened and forces the spring end 73 downwardly and outwardly into the slot 112 between the fingers 107 on the latch member 27.

The spring body 29 is conveniently mounted in the buckle by a pair of downwardly turned flanges 129 which are apertured at openings 131 to receive the pivot pin 79. The flanges 129 are disposed between the trunnion arms 93 of the latch member 27 and the side flanges 39 of the buckle base. For the purpose of anchoring the spring body against pivoting upwardly about the pivot pin 79, the spring body has stop tabs 133 bent outwardly from the flanges 129 to fit beneath lugs 135 on the sections 43 of the side flanges 39 of the buckle base 21. The lugs 135 are formed by striking portions of these flanges inwardly to positions parallel to the straight portions of the side flanges. The openings formed by striking the lugs from the flange sections 43 remain covered by the depending sidewalls 63 of the cover lever 19.

As an aid to understanding the invention, a brief description of the operation of the safety seatbelt buckle will be given. To latch the tongue plate 15 to the buckle base 21, the tongue plate is inserted into the slot 17 and slid along the buckle baseplate 41 to abut the underside of the latch dog 25 to pivot it away from the baseplate 41. As the latching dog 25 and member 27 pivot, they further flex the leaf springs 35 on the top of the central plate 95 of the latching member. When the latch opening 23 in the tongue plate is aligned with the latching dog 25, the dog snaps into the latch opening to bring its abutment wall 103 against an abutment wall 105 defining the forward edge of the latch opening. In this position, the latching member is in its latching position and the tongue plate 15 is latched against removal from the buckle base. During this insertion of the tongue plate, the cover lever 19 remains stationary as the fingers 107 are rotated away from the abutment pads 75 on the cover lever.

To unlatch the tongue plate 15, the operator grasps the free end 31 of the cover lever 19 and pivots the same about the pivot pin 79 to bring abutment pads 75 into engagement with the edges 34 of the latching member fingers 107. The amount of initial pivotal movement of the cover lever to take up the gap 113 without an accompanying pivoting of the latching member will vary as a result of manufacturing tolerances for the individual elements comprising the buckle. During this initial pivotal movement, the leaf spring 37 is flexed into the clearance slot 112 in the latching member.

With the abutment pads 75 engaging the edges 34 of the fingers 107 of the latching member, continued opening of the cover lever 19 pivots the latching member upwardly until the top forward edges of its trunnion arms 93 abut against the central web 115 of the spring body 29. As the spring body 29 is held against pivotal movement in this direction by the tabs 133 engaging the lugs 135 of the buckle base, the latching member is also held and limited against further upward swinging. This, in turn, limits the upward swinging movement of the cover lever 19 in a most beneficial manner because the stopping is against a resilient body.

As the latching dog 25 is now removed from the latch opening 23 in the tongue plate 15, the tongue may be withdrawn from the buckle base. The latching member 27 pivots under the urging of the flexed leaf springs 35 to engage the latching dog 25 against the buckle base 41. At the same time, the leaf springs 35 act through the latching member 27 to close the cover lever 19, the fingers 107 of the latching member pushing against the abutment pads 75 of the cover lever. To assure no rattling even with loose tolerances, the leaf spring 37 urges the abutment surfaces 77 on the cover lever wall 61 against the belt loop 49 and at the same time forces the flat ends 59 of the knurled rod 51 downwardly against the bottom walls of the elongated slots 57 to prevent any rattling of the rod.

When assembling the buckle, the latch member 27 is disposed on the base with the openings 97 on the trunnion arms 93 aligned with the openings 81 in the buckle base flanges 39. The spring body 29 is then disposed over the latch member with its apertures 131 generally aligned with the openings 81 and 97 and with its flanges 129 intermediate the latch member trunnion arms 93 and the buckle side flanges 39. The leaf springs 35 and 37 are depressed and flexed as the cover lever 19 is disposed over the side flanges of the buckle base, and the shaft of the pivot pin 79 is inserted through the openings in the sidewall of the cover lever and aligned openings in the buckle base, the spring body and the latch member. From the opposite side of the buckle base, the locking pin 91 is inserted to bring its shaft into alignment with the bore 87 in the pivot pin, and the locking pin is driven axially inwardly to achieve a tight-locking fit. Thus, the enlarged heads on the pivot and locking pins hold the pivot pin against axially sliding from the cover lever.

From the foregoing, it will be seen that the seatbelt buckle employs inexpensive elements which need not be precisely controlled as to their dimensions. A unique spring body is of a construction which is low cost, facilitates assembly of the buckle and performs a number of functions.

While a preferred embodiment has been shown and described, it will be understood that there is no intent to limit the invention by such disclosure but, rather, it is intended to cover all modifications and alternate constructions falling within the spirit and scope of the invention as defined in the appended claims.

Claims

I claim:

1. A safety seatbelt buckle comprising a buckle base having a central baseplate and a pair of upstanding flanges extending along a pair of said opposite sides of said baseplate, a pivot pin spanning said flanges and spaced from said baseplate, a cover lever pivotally mounted on said pivot pin for movement between open and closed positions, a latch member pivotally mounted on said pivot pin, a tongue plate insertable into an opening between said cover lever and said plate and slideable longitudinally relative to said baseplate and including an abutment wall defining a latch opening in said tongue plate, a latch dog carried by said latch member and movable upon pivoting of said latch member between a release position in which said tongue plate can be retracted from said buckle and a latching position in which said dog projects into said latch opening and engages said abutment wall on said tongue plate, actuating means on said cover lever separated by a gap from said latch member when said cover lever is in its closed position and movable to engage and pivot the latch member to release position as said cover lever is pivoted to its open position, and a spring body disposed between said cover lever and said buckle base, said spring body having a portion thereof connected to said buckle base and having a first leaf spring biasing said latch member and said latch dog toward said latching position and a second leaf spring biasing said cover toward its closed position.

2. A safety belt buckle in accordance with claim 1 in which said spring body is secured to said base and has a portion which limits the pivotal movement of said latch member at its release position thereby limiting the opening movement of said cover lever.

3. A safety belt buckle in accordance with claim 1 in which said spring body is mounted on said pivot pin.

4. A safety belt buckle in accordance with claim 3 in which portions of said base are interlocked with said spring body to hold the same against rotating about said pivot pin when said latch member strikes said spring body.

5. A safety belt buckle in accordance with claim 1 in which said first spring leaf engages said latching member on one side of said pivot pin and biases the same downwardly toward said central baseplate and in which said second leaf spring curves about said pivot pin to engage said cover member on the other side of said pivot pin and exerts an upward force on one end of said cover and biases it toward its closed position.

6. A safety belt buckle in accordance with claim 5 in which said latch member is provided with an opening and in which said second leaf spring projects into said opening when flexed by said cover lever.

7. A safety belt buckle in accordance with claim 6 in which said actuating means on said cover lever includes abutment surfaces disposed on the interior side of said cover lever spaced from an adjacent portion of said latching member when said cover is closed, pivoting of said cover lever toward its release position causing said abutments to engage and pivot said latching member to its release position.

8. A safety belt buckle in accordance with claim 1 in which said side flanges of said base have elongated slots, and which includes a bar for a belt webbing slideably mounted in said slots, and means on said cover biasing said belt webbing and bar against the walls of said slots to hold the bar against rattling when said cover is in its closed position.

9. A safety belt buckle in accordance with claim 8 in which a blocking wall projects from the interior surface of said cover toward said base and extends laterally between said side flanges of said base to block a false insertion of said tongue plate, said blocking wall being disposed inwardly of the free end of said cover lever to permit insertion of the finger tips of the operator for a predetermined distance to permit grasping of the free end of the cover lever.

10. A safety seatbelt buckle comprising a buckle base having a central baseplate and a pair of upstanding flanges extending along a pair of said opposite sides of said baseplate, a cover lever pivotally mounted at one end of said buckle base for movement between open and closed positions, a latch member pivotally mounted on said base, a tongue plate insertable into an opening between said cover lever and said baseplate and slideable longitudinally relative to said baseplate and including an abutment wall defining a latch opening in said tongue plate, a latch dog on said latch member movable between a release position in which said tongue plate can be retracted from said buckle and a latching position in which said dog projects into said latch opening and engages said abutment wall on said tongue plate, an abutment surface on said cover lever spaced from and movable to engage and pivot the latch member to its release position as said cover lever is pivoted to its open position whereby said tongue plate may be withdrawn from said buckle, and a spring body having a central web overlying said latch member extending laterally of said buckle base to adjacent said upstanding flanges of said buckle base, a portion of said spring body being interlocked with said buckle base, said spring body web serving as a stop for said latch member at its release position, a first leaf spring on said spring body extending downwardly from said web to engage said latch member on one side of said pivotal axis and exerting a downward force to pivot said latch member against said central baseplate, and a second leaf spring on said spring body extending to the opposite side of said pivotal axis and exerting an upward force on the rearward end of said cover lever biasing the same toward a closed position.