Adjustable strap fastener

Abstract

An adjustable strap fastener comprises a housing defining a guideway slidably receiving a substantially flat slider plate having a single locking bar around which a strap is looped. The slider plate is biased to a strap clamping position and an integral release tab on the slider plate extends through a release tab opening in the housing so that manual force can be applied to the release tab for moving the slider plate away from its strap clamping position. Cooperating integral stop means on the housing and slider plate prevents complete displacement of the slider plate from the guideway through the release tab opening in the absence of a strap looped around the locking bar.

Description

BACKGROUND AND SUMMARY OF THE INVENTION

This application pertains to the art of strap fasteners, and more particularly to adjustable strap fasteners of the slider plate-type. This invention is particularly applicable for use with passenger seatbelts having web belting, although it will be appreciated that the invention may also be used with other types of straps and on other harnesses such as cargo tie-downs or the like.

An adjustable strap fastener of the slider plate-type is disclosed in U.S. Pat. No. 3,414,947 issued Dec. 10, 1968, to Holmberg et al. Such fastener includes a housing defining a guideway which slidably receives a flat slider plate having a clamping bar around which a strap is looped through an access opening in the housing. A spring biases the slider plate to a clamping position wherein the belt is clamped between an edge of the clamping bar and an edge of the housing access opening.

In the aforementioned device, the slider plate is substantially completely enclosed and is not accessible externally of the housing. Therefore, adjustment of the strap length by sliding such strap relative to the clamping bar must take place by pulling on the strap in a certain direction to move the clamping bar to a strap releasing position against the biasing force of the spring. However, the strap always remains clamped somewhat and sliding movement thereof for increasing or decreasing the length of the strap is rather cumbersome and difficult. In addition, adjusting the strap in this manner while the clamping force is still applied thereto causes more rapid abrasion of the strap and can result in early failure.

U.S. Pat. No. 2,938,254 issued May 31, 1960, to Gaylord discloses an adjustable strap fastener having a slidable clamping bar which can be manually grasped for moving it to a strap unclamping position against the biasing force of a spring for easy adjustment of the strap relative to the clamping bar. However, the Gaylord clamping bar is not enclosed within a housing and exposure of the entire mechanism subjects it to damage, either intentional or accidental, and it is unsightly in appearance. Furthermore, the Gaylord fastener requires an additional slide member for acting against the clamping bar, and this makes the structure more complicated and expensive.

The present invention is directed to an adjustable strap fastener of the slider plate-type as generally disclosed by Holmberg, and which includes a release tab on the slider plate accessible externally of the housing so that manual force can be applied thereto for moving the slider plate to a strap unclamping position for easy adjustment of the strap length by sliding the strap relative to the clamping bar.

In a preferred arrangement, integral cooperating stop means are provided on the slider plate and housing for preventing complete displacement of the slider plate through a release tab opening in the housing in the absence of a strap looped around the clamping bar. When a strap is looped around the clamping bar, displacement of the slider plate through the release tab opening is prevented by clamping engagement of the strap between the clamping bar and an edge of an opening in the housing through which the strap extends.

The housing includes a flat base plate having a cover member releasably attached thereto, and such base plate has opposite reversely bent edges providing channels having opposed facing grooves defining the guideway for the slider plate. The grooves have a predetermined groove height and in a preferred arrangement the slider plate has a thickness substantially less than the groove height. The slider plate includes opposite upwardly extending rear guide legs received in the grooves, and such legs have a length greater than the thickness of the slider plate and slightly less than the groove height. The base plate has a locking tongue cooperable with a buckle and must be of relatively heavy gage metal to have adequate strength in the area of its locking tongue and in its reversely bent edges.

The cover member has depending front and rear flanges extending perpendicular to the grooves and spaced apart a distance slightly less than the length of the channels. Such flanges are in resilient gripping engagement with the opposite channel ends for releasably attaching the cover to the base plate. The front flange of the cover member has a terminal end portion spaced from the face of the base plate a distance slightly greater than the thickness of the slider plate to define the release tab access opening and insure free sliding movement of the slider plate. With such an arrangement, the described rear legs on the slider plate can act as the stop means by engaging the front flange of the cover member to prevent complete displacement of the slider plate from the grooves through the release tab opening. In another arrangement, the front flange of the cover member includes extended opposite end portions closing the front ends of the grooves and cooperable with stop shoulders on the slider plate for limiting outward movement of the slider plate.

In accordance with a preferred arrangement, the cover member is of plastic material and includes an integral spring support depending therefrom in spaced relationship to the rear flange. Such spring support is closely received through a hole in the base plate for imparting stiffness thereto, and an arcuate leaf spring member is positioned under stress between the spring support and rear end of the slider plate for biasing each slider plate toward its strap clamping position.

Other objects and advantages of the present invention will be apparent to those skilled in the art as the description proceeds when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross-sectional view of an adjustable strap fastener constructed in accordance with the present invention;

FIG. 2 is a cross-sectional plan view looking generally in the direction of arrows 2--2 of FIG. 1; and

FIG. 3 is a front elevational view looking generally in the direction of arrows 3--3 of FIG. 1.

DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now to the drawings, wherein the showings are for purposes of illustrating a preferred embodiment of the invention only and not for purposes of limiting same, FIG. 1 shows a flat metal base plate A having a plastic cover member B releasably secured thereto and cooperating therewith to define a fastener housing which substantially encloses a cavity having a guideway in which flat slider plate C is slidably mounted.

Base plate A has an extending locking tongue 12 including at least one hole 14 and such tongue is receivable in a buckle on another strap in a known manner. The opposite longitudinal edges of base plate A are bent upwardly and inwardly in such a manner that the inwaredly bent portions extend over the surface of such plate in outwardly spaced relationship thereto for defining grooves 18 (best shown in FIG. 3) which provide the guideway for slider plate C.

Flat slider plate C has a width slighty less than the distances between grooves 18 and includes a pair of upwardly extending rear legs 20 having a length slightly less than the height of grooves 18. A rectangular opening 22 in slider plate C is spaced from the rear edge of such slider plate and defines a clamping bar portion 24 located at the rear edge of the slider plate. A strap D extends through a rectangular opening 26 in a base plate A and into the cavity defined between the base plate A and cover member B. The strap D also extends around clamping bar 24 through opening 22 and back through opening 26 in the base plate A. The belt is releasably clamped in such position and may be adjusted, as will be described hereinbelow.

The forward corner portions of slider bar C are notched to provide shoulders 28 and also includes an integral centrally located outwardly extending release tab 30 which extends outwardly from the cavity defined between base plate A and cover member B through a release tab opening which will be more particularly described hereafter.

Cover member B is molded in one piece of any suitable synthetic plastic material such as a polyamide or polyvinylchloride compounded so that cover member B is slightly resilient. Cover member B has depending front and rear flanges 32 and 34 which are internally spaced apart a distance slightly less than the length of channels 16 so that such flanges resiliently grip the ends of channels 16 when cover member B is forced over such channels. Terminal end 36 of front flange 32 is spaced from the facing surface of base plate A a distance slightly greater than the thickness of slider plate C to define the release tab opening through which the release tab 30 projects in free sliding relationship.

In one arrangement, front flange 32 may be dimensioned so that the undersurface of cover B will abut against the top of flanges 16 for properly spacing terminal end 36 of front flange 32 from the facing surface of base plate A so that the release tab opening will be slightly greater than the thickness of slider plate C. In another arrangement, front flange 32 has extended opposite end portions 40 (see FIG. 3) which close the front ends of grooves 18 and contact the facing surface of base plate A to function as abutments for properly spacing terminal end 36 relative to the facing surface of base plate A instead of using the undersurface of cover B for such spacing purpose as aforementioned. Extended opposite end portions 40 may function as stop means in cooperation with shoulders 28 for preventing complete displacement of slider plate C from its position between cover B and base plate A in the absence of a belt D looped around clamping bar 24.

Cover member B has an integral spring support 42 extending downwardly therefrom in spaced relationship to rear flange 34. Spring support 42 may have any cross-sectional configuration but is shown as having a generally rectangular cross-sectional configuration. The support has a length sufficient for extending through a generally correspondingly shaped hole 44 in base plate A. An arcuate leaf spring 46 has its central portion bearing against spring support 42 and inwardly curved opposite end portions 48 bearing against the legs 20 on slider plate C. Leaf spring 46 is stressed between spring support 42 and legs 20 for biasing slider plate C to the right in FIGS. 1 and 2.

The advantageous arrangements described makes it possible to stamp slider plate C from relatively light gauge metal while maintaining a close sliding fit thereof in grooves 18 by providing upwardly extending legs 20 which also provide adequate bearing for end portions 48 of spring 46.

To assemble the fastener, slider plate C and leaf spring 46 are positioned in grooves 18. Spring support 42 is then guided through opening 44 with spring 46 positioned between such support and upstanding legs 20. Continued pressure on cover member B will then cause front and rear flanges 32 and 34 to resiliently deform outwardly for resiliently gripping the opposite ends of channels 16. Where terminal end 36 of front flange 32 extends the full length of cover member B, upstanding legs 20 and front flange 32 provide cooperating stop means for preventing complete displacement of slider C from the cavity defined between base plate A and cover member B. Where front flange 32 is provided with opposite extended portions 40, spring support 42 is first positioned behind leaf spring 46 and partially into opening 44 so that manual force can be applied to release tab 30 for moving slider plate C to a position wherein shoulders 28 are inside of extended portions 40. Continued pressure on cover member B will then cause front and rear flanges 32 and 34 to resiliently grip the opposite ends of channels 16, and shoulders 28 will be trapped behind opposite extended portions 40 to cooperate therewith in defining the cooperating stop means which prevents complete displacement of slider plate C through the release tab access opening.

Where the fastener is shipped without being attached to a belt D, cover member B is simply snapped off from channels 16 so that free end 50 of belt D can be extended upwardly through base plate opening 26, and then looped around clamping bar 24 and back out through base plate opening 26. Cover member B is then replaced in the manner previously described.

Once the belt D is looped around clamping bar 24, portion 52 of belt D is clamped between the forward edge of clamping bar 24 and the forward edge of opening 26 due to leaf spring 46 biasing slider plate C forwardly. For adjusting the length of belt portion 52, the fastener is simply grapsed with one hand and fingers are used for applying force to the end of release tab 30 for moving slider plate C inwardly against the biasing force of spring 46 for freeing tensioned portion 52 of belt D from clamping engagement between clamping bar 24 and an edge of opening 26 so that the entire assembly can be slid or moved along the belt D to a new position which would either decrease or increase the length of the portion 52 of the belt.

Although the invention has been shown and described with respect to a preferred embodiment, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification. The present invention includes all such equivalent alterations and modifications, and is limited only by the scope of the claims.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An adjustable strap fastener comprising; a housing defining a cavity having a belt access opening thereto, said housing including a base plate and a cover member, said base plate having opposite reversely bent edges providing channels having opposed facing grooves defining a guideway in said housing, said cover member being of plastic material and having front and rear depending flanges extending perpendicular to said grooves and spaced apart a distance slightly less than the length of said channels, said flanges being in resilient gripping engagement with the opposite ends of said channels, said cover member having an integral plastic spring support extending downwardly therefrom in spaced relationship to said rear flange through a hole in said base plate, a substantially flat slider plate slidably received in said guideway and having a single clamping bar, a strap extending through said access opening in said housing and around said clamping bar, biasing means for biasing said slider plate to a strap clamping position wherein the strap is clamped between opposed edges of said clamping bar and said access opening, said biasing means comprising an arcuate leaf spring stressed between said spring support and the rear end of said slider plate, said housing further defining a release tab opening, said front flange having a terminal end spaced from said base plate a distance slightly greater than the thickness of said slider plate to define said release tab opening, and an integral release tab on said slider plate projecting outwardly of said cavity through said release tab opening, said release tab being positioned for application of manual force thereto for sliding said slider plate away from said clamping position against the force of said biasing means.

2. The fastener of claim 1 wherein said grooves have a predetermined groove height and said slider plate has a thickness substantially less than said groove height, said slider plate including opposite upwardly extending rear legs having a length greater than the thickness of said slider plate and slighty less than said groove height.

3. The fastener of claim 2 wherein said legs and said front flange define said integral stop means for preventing displacement of said slider plate from said cavity through said release tab opening.

4. An adjustable strap fastener comprising; a housing defining a cavity having a belt access opening thereto, there being a guideway in said housing, a substantially flat slider plate slidably received in said guideway and having a single clamping bar, said housing including a base plate and a cover member, said base plate having opposite reversely bent edges providing channels having opposed facing grooves defining said guideway, said grooves have a predetermined groove height and said slider plate has a thickness substantially less than said groove height, said slider plate including opposite rear legs extending transversely to a major side surface of said slider plate and having a length greater than the thickness of said slider plate and slightly less than said groove height, said cover member being of plastic material and having front and rear depending flanges extending perpendicular to said grooves and spaced apart a distance slightly less than the length of said channels, said flanges being in resilient gripping engagement with the opposite ends of said channels, a strap extending through said access opening in said housing and around said clamping bar, biasing means for biasing said slider plate to a strap clamping position wherein the strap is clamped between opposed edges of said clamping bar and said access opening, said housing further defining a release tab opening, said front flange having a terminal end spaced from said base plate a distance slightly greater than the thickness of said slider plate to define said release tab opening, and an integral release tab on said slider plate projecting outwardly of said cavity through said release tab opening, said release tab being positioned for application of manual force thereto for sliding said slider plate away from said clamping position against the force of said biasing means.

5. The fastener of claim 4 wherein said legs and said front flange define stop means for preventing displacement of said slider plate from said cavity through said release tab opening.

6. The fastener of claim 4 wherein said cover member has a spring support extending downwardly therefrom in spaced relationship to said rear flange through a hole in said base plate, said biasing means comprising an arcuate leaf spring stressed between said spring support and the rear end of said slider plate.

7. The fastener of claim 4 further including cooperating stop means on said housing and slider plate for preventing displacement of said slider plate from said cavity through said release tab opening in the absence of a strap looped around said clamp bar.

8. The fastener of claim 4 wherein said biasing means comprises an arcuate leaf spring having opposite curved ends bearing against said legs.

9. An adjustable strap fastener comprising; a base plate defining a longitudinally extending strap access opening, said base plate having a pair of major side surfaces and a plurality of minor side surfaces extending between said major side surfaces, means for defining a pair of channels extending perpendicular to a central axis of said strap access opening, each of said channels being disposed adjacent to an associated end portion of said strap access opening, a slide plate having major side surface disposed in flat abutting engagement with one of the major side surfaces of said base plate, said slide plate having opposite side portions disposed in said channels, said slide plate having a single clamp bar which extends perpendicular to said channels and is defined by opposite major side surfaces of said slide plate and a plurality of minor side surfaces of said slide plate and a plurality of minor side surfaces which extend between the major side surfaces of said slide plate, a strap extending through said strap access opening, around said single clamp bar and back through said strap access opening, a cover member cooperating with said one major side surface of said base plate to at least partially define a cavity in which said channels and single clamp bar are disposed, said cover having a pair of end walls which extend perpendicular to said channels, one of said end walls having a minor side surface which is spaced apart from and extends parallel to said one of the major side surfaces of said base plate, said minor side surface of said cover end wall and said one major side surface of said base plate cooperating to at least partially define a release tab opening which extends perpendicular to said channels, a release tab extending through said release tab opening and being formed by a portion of said slide plate, said release tab having a major side surface at least a portion of which is disposed in flat abutting engagement with said one major side surface of said base plate, said release tab being movable along a path extending parallel to said channels from a first position in which said single clamp bar is effective to press said strap against a minor side surface of said base plate and a second position in which said single clamp bar is ineffective to press said strap against a minor side surface of said base plate, and a leaf spring disposed within said cavity between said cover member and said one major side surface of said base plate, said leaf spring being effective to urge said release tab toward said first position.