ANTI-ROPING LATCH PLATE

Abstract: A latch plate (50) for use with a seat belt and seat belt buckle has a metal load-bearing plate (52) including a generally flat tongue (22) for engaging a locking feature (54) of the seat belt buckle. A portion of the bearing plate, rearward of the tongue, has a surface (70) that includes a lateral extending rearward edge (72). A second portion of the bearing plate includes an integrally formed tab (74) having a laterally extending forward edge. The tab is spaced from the first surface defining a thin channel (80) or opening therebetween through which the seat belt is received. The distance is sufficiently narrow to lessen the likelihood of the seat belt becoming twisted in the channel.

Description: A TI-ROPING LATCH PLATE The invention relates to an anti-roping latch plate for use with a seat belt buckle. FIGS. 1 and 2 show a prior art latch plate 20. The latch plate comprises a tongue portion 22 having a first latching feature 24, such as an opening, which s engages a locking mechanism of a seat belt buckle. The latch plate further includes a rear or plate portion 26 having an oblong opening 28 of sufficient size to permit the seat belt 30 to extend therethrough. The rearward end 26a of plate 26 is often bent away from the plane of the tongue as illustrated in FIG. 2. To reduce the wear on the seat belt 30, the latch plate 20 in the vicinity of opening 28 may be covered by a low-friction plastic coating. Over time as the vehicle occupant buckles and unbuckles the seat belt, the seat belt often curls upon itself or otherwise twists in the opening 28. This curling, twisting, or folding of the seat belt is commonly called "roping" and is lessened by the latch plate set forth in appended Claim 1. There is provided in accordance with the present invention a latch plate for use with a seat belt and seat belt buckle, comprising: a metal load-bearing plate including a tongue for engaging a locking feature of the seat belt buckle, the load-bearing plate also defining a belt receiving opening located between first and second generally parallel surfaces, the first and second parallel surfaces defining a channel to guide the seat belt as it exits the belt receiving opening. Brief Description of the Drawings FIGS. 1 and 2 show a prior art latch plate. FIG. 3 is a top plan view of a load-bearing plate. FIG. 4 is a cross-sectional view through section 4-4 of FIG. 3. FIG. 5 is a cross-sectional view of the plate with a tab rotated upwardly taken through section 5-5 of FIG. 6. FIG. 6 is an isometric view of the load-bearing plate of FIG. 5. FIG. 7 is a cross-sectional view through section 7-7 of FIG. 8 and includes a plastic coating on portions of the plate. FIG. 8 is an isometric view of a latch plate according to the present invention. FIG. 8a is a front plan view of a load-bearing plate . FIG. 8b shows a further embodiment of the invention. FIGS. 9 and 9a show an alternate embodiment of the invention. FIGS. 10-13 show another embodiment of the present invention. FIG. 13a is a front plan view of an alternate embodiment of the invention. FIG. 14 diagrammatically shows the latch plate of the present invention secured to a seat belt buckle. FIG. 15 shows a typical three-point seat belt system. Detailed Description of the Invention FIGS. 3 and 4 illustrate a load bearing plate 52 that is the major component of a latch plate 50. The load bearing plate includes a first locking feature 54 such as an opening, which engages a latch mechanism 57 of a buckle 56 shown in FIG. 14. FIG. 14 shows the buckle with a rotatable latch mechanism that engages the latch plate 50 in a locking manner. The opening or locking feature 54 in the load bearing plate 52 is formed within a tongue 58 portion of the load bearing plate. The load-bearing plate, in a rearward, second portion 60 thereof, includes an integrally formed tab 62. The tab is formed by stamping or otherwise forming a narrow U-shaped slot 64 in the load bearing plate. The load bearing plate includes a first surface 70 that is positioned forward of the slot . In the first preferred embodiment of the invention this first surface is flat. Subsequent to forming the opening 54 and the slot 64, the tab 62 is rotated upwardly as illustrated in FIGS. 5 and 6. The rear laterally extending edge 72 of the first surface and the forward edge 74 of the tab are more clearly visible in FIG. 6. With the tab bent as illustrated, the forward edge 74 is positioned apart from edge 72 defining a channel 80 therebetween. Subsequently, the load bearing plate 52 is bent (see FIGS. 7 and 8) about bend line 82 thereby positioning a rear portion 52a of load bearing plate at an angle relative to the tongue 58. This rotation of the load bearing plate moves the forward edge 74 forwardly closer to the tongue. Depending upon the location of the fold line and the dimensions of the tab, the forward edge of the tab will be moved in line with the rearward edge 72 or be positioned slightly forward of the rearward edge to overlay the first surface 70. The resulting configuration is shown in FIG. 8. In this configuration, the tab 62 is preferably parallel to the first surface, as can also be seen in FIG. 8a. FIG. 8 shows the seat belt 30 in phantom line extending through the latch plate 50 and more particularly extending through the channel 80. The seat belt 30 is now guided between two parallel walls, the first formed by the first surface 70 and the second formed by the lower surface 62a of the tab 62. The roping, i.e., twisting, curling, etc. of the seat belt is now at a minimum because of the close spacing of the channel to the seat belt and its parallel construction. These walls are preferably parallel but can diverge + or - 10 degrees from parallel . The latch plate 50 of FIG. 8 is fully functional; however, latch plates typically include a low-friction elastomeric coating disposed on various parts of a metal load-bearing plate to protect the seat belt 30. FIG. 7 shows this coating 90 disposed on the first surface and about edge 72 as well as about rearward portion 52a of the load bearing plate 52. FIG. 7 shows the seat belt fitted through channel 80, which in this case is defined by the spacing between the adjacent upper and lower layers of the coating material 90. In certain applications, it might be desirable to limit the extent to which the rear portion 52a extends outwardly from the tongue 58. If this alternate configuration is desirable, the rear portion 52a is again bent about a second bend line 80a, which places the rearmost portion 53 (shown in phantom line in FIG. 8) of the load bearing plate 52 in an orientation generally parallel to that of the tongue. This configuration is also shown in FIG. 8b. FIGS. 9 and 9a and FIGS. 10-12, show two additional preferred embodiments of the invention. The channel 80 in the earlier embodiment is formed by two flat surfaces 62a, 70, that are coated with a thin layer of plastic material. In the following embodiments the channel 80 includes a plurality of separated projections. FIG. 9 is identical to FIG. 7 with the exception that the plastic coating on the surfaces 62a and 70 is molded to provide a plurality of respective projections 100, 102. FIG. 9a is a front view of the latch plate, without the seat belt therein, and shows the relationship between the alternating projections on each of the above surfaces. The projections 102 can for example be circular and/or oblong. As mentioned above, the first surface 70 can be flat. However, in the following embodiment, one or more projections 100 are provided on the first surface. Alternatively, or in combination with the projections, another plurality of projections 102 are also located on the undersurface 62a of the tab. FIG. 10 is a plan view of the load-bearing plate 52 illustrating a plurality of hemispherically- shaped projections 100 on the first surface 70 and, for the purpose of illustration, oblong-shaped projections 102 on the tab 62. These projections can easily be formed during the stamping process during which the latch plate 50 is formed. FIG. 11 is a cross-sectional view taken through section line 11-11 of FIG. 10 and shows the relationship between the projections 100, 102 prior to the bending of the tab 62 upwardly (as in FIG. 12) . In this alternate embodiment, after the tab 62 is bent upwardly, the load bearing plate 52 is bent in the manner as described in relation to FIGS. 6 and 8. The resulting configuration is illustrated in FIG. 13. FIG. 13 also shows the coating material 90, which now also covers the projections 100, 102. FIG. 13a is a front plan view of this alternate latch plate showing the relationship of the projections, as well as the channel 80 through which the seat belt 30 is received. FIG. 15 shows a typical three-point seat belt system 150. The system 150 comprises a seat belt retractor 160 of known variety. Extending from the retractor is the seat belt, which is divided into a shoulder belt portion 30a and a lap belt portion 30b. The latch plate 50 of the present invention essentially divides the seat belt 30 into the shoulder belt and lap belt portions. The remote end of the lap belt is secured, such as to the floor, by an anchor 162. The buckle 56 is similarly secured by another anchor 162. The seat belt is also threaded through a web guide or D-ring 164. When the latch plate 50 is detached from the buckle 56 the retractor 160 will rewind the seat belt 30 onto a spool (not shown) of the retractor. In this configuration, the lap belt portion 30b will be vertically oriented and extend downwardly from the web guide . In the stowed configuration, the web guide is also vertical and is shown in this configuration in phantom line. Depending on the relative size of the height of the channel 80 and relation to the thickness of the seat belt 30, the latch plate 50 will fall into one of two categories of latch plates, that is a free-sliding latch plate or a free-falling latch plate. If the channel 80 is narrow, as in the free-sliding latch plate, the seat belt will generate a low level of friction on the latch plate such that upon retraction of the seat belt into the retractor the unbuckled latch plate will be carried with the seat belt to its stowed position (shown in phantom line in FIG. 15) . Quite often the latch plate will be carried up to the web guide and as the retractor continues to retract, the seat belt will be pulled through the latch plate which has come to rest at the location of the web guide. The free-sliding latch plate may slide down the vertically stowed seat belt when it is not in use. In the case of the free-falling latch plate, the size of the channel 80 is slightly oversized so that when the latch plate is unbuckled from the buckle, the latch plate may initially be carried upwardly with the retracting seat belt but, due to the lower level of friction, the latch plate will fall down to the position of a stop with the seat belt in its vertically stowed orientation. The stop is usually achieved by adding a small button 166 or the like to the seat belt.

Claims: Cl aims : 1. A latch plate (50) for use with a seat belt and seat belt buckle, the latch plate comprising: a metal load bearing plate (52) including a tongue for engaging a locking feature (54) of the seat belt buckle, a first portion of the bearing plate, rearward of the tongue (58), having a first surface, the first surface (70) including a lateral extending rearward edge (72) ; the bearing plate, in a second portion thereof, including an integrally formed tab (62) having a laterally extending forward edge (74), the forward edge of the tab (74) overlaying the rearward edge (72) of the first surface, the tab being spaced a determinable distance from the first surface defining a thin channel or opening (80) therebetween through which the seat belt is received, the distance being sufficiently narrow to lessen the likelihood of the seat belt becoming twisted in the channel . 2. The latch plate (50) for use with a seat belt and seat belt buckle defined in Claim 1 wherein the first surface is flat. 3. The latch plate (50) for use with a seat belt and seat belt buckle defined in Claim 1 wherein one of the first surface and the tab is generally flat and includes a plurality of upraised projections thereon. 4. The latch plate (50) for use with a seat belt and seat belt buckle defined in Claim 1 wherein the tab is generally parallel to the first surface. 5. The latch plate (50) for use with a seat belt and seat belt buckle defined in Claim 1 wherein the at least facing portions of the tab and the flat surface, in the vicinity of the channel, are covered by a low friction, elastomeric coating to permit the latch to easily slide upon the seat belt. 6. The latch plate (50) for use with a seat belt and seat belt buckle defined in Claim 1 wherein the first surface of the bearing plate and the tongue lie in the same plane. 7. The latch plate (50) for use with a seat belt and seat belt buckle defined in Claim 1 wherein a third portion of the bearing plate, rearward of the second portion, is elevated relative to the tongue. 8. The latch plate (50) for use with a seat belt and seat belt buckle defined in Claim 1 wherein the bearing plate includes a thin U-shaped slot immediately rearward of the first surface, the U- shaped slot forming the tab, the rearward edge of the first surface and the forward edge of the tab. 9. The latch plate (50) for use with a seat belt and seat belt buckle defined in Claim 8 wherein the tab is initially bent at an angle away from the plane of the tongue, and wherein the bearing plate is bent in the vicinity of the slot to position the forward edge of the tab to overlay the rearward edge of the first surface. 10. The latch plate (50) for use with a seat belt and seat belt buckle defined in Claim 5 wherein the coating, with the channel, includes a plurality of projections projecting into the channel.

Inventors: BELL STEVEN C, BELL, STEVEN, C.
Applicants: BREED AUTOMOTIVE TECH, BREED AUTOMOTIVE TECHNOLOGY, INC.
Application year: 2000
Main classification: B60R22
IPC codes: A44B11, B60R22