Free falling locking tongue

A locking tongue seat belt assembly includes a tongue plate with a pair of side portions, an end flange that extends along the rear of the tongue plate, a pair of spaced apart side flanges that extend from the tongue plate along respective side portions of the tongue plate, and a lock bar that extends between the two side flanges. The ends of the lock bar are guided in respective slots of the side flanges such that the lock bar is movable between a locked position and an unlocked position. The lock bar and the end flange are configured to receive seat belt webbing between the lock bar and the end flange. The seat belt webbing is cinched between the lock bar and the end flange when the lock bar is in the locked position.

BACKGROUND

The present invention relates generally to a free falling locking tongue for a seat belt.

In many types of tongues for seat belt systems, belt slippage from the shoulder portion to the lap portion occurs during occupant excursion, which leads to an increase in the force on the shoulder portion of the belt and therefore an increase in occupant chest deflection. Locking tongues have been employed in certain seat belt systems. These tongues prevent the translation of the webbing from the shoulder portion to the lap portion and therefore reduces loading on the occupant's chest. In particular, the locking tongues are able to slide on the seat belt webbing to provide a proper fit over the occupant but are also able to lock or cinch the webbing during sudden deceleration of the vehicle to prevent loosening of the seat belt to properly protect the occupant.

Such locking tongues, however, have been used mostly in two point applications, since when used in three point applications, these locking tongues often result in a long piece of hanging webbing getting caught in the vehicle's door when it is closed because of poor free sliding performance of the tongue. Further, in these tongues, the seat belt webbing typically passes through an aperture in the tongue body and then wraps around a lock bar, which generates uneven load distribution across the webbing when the webbing is cinched or pinched between the lock bar and the edge of the aperture.

BRIEF SUMMARY

To overcome the enumerated drawbacks and other limitations of the related art, the present invention provides a free falling locking tongue for seat belt systems. The locking tongue includes a tongue plate with a pair of side portions, an end flange that extends along the rear of the tongue plate, a pair of spaced apart side flanges that extend from the tongue plate along respective side portions of the tongue plate, and a lock bar that extends between the two side flanges. The ends of the lock bar are guided in respective slots of the side flanges such that the lock bar is movable between a locked position and an unlocked position. The lock bar and the end flange are configured to receive seat belt webbing between the lock bar and the end flange. The seat belt webbing is cinched between the lock bar and the end flange when the lock bar is in the locked position.

In some arrangements, the locking tongue includes a sleeve that encapsulates the lock bar. The sleeve may have an outer contour that matches the profile of the contour of the end flange.

Some embodiments of the invention may have one or more of the following advantages. Since the seat belt webbing simply passes through the locking tongue body between the lock bar and the end flange rather than through an aperture in the body of the tongue plate, the configuration of the locking tongue may minimize the complexity of the seat belt webbing through the locking tongue assembly. As such, the potential for tearing the webbing is reduced when a load is applied to the webbing. By matching the contour of the sleeve with the contour of the end flange, the tension in the webbing is distributed across the width of the webbing.

Further features and advantages will become apparent from the following description and from the claims.

DETAILED DESCRIPTION OF THE INVENTION

Referring now toFIGS. 1 through 5, a free falling locking tongue for a seat belt assembly embodying the principles of the present invention is illustrated therein and designated at10. The locking tongue10includes a tongue plate12with a tongue portion14and a pair of side portions16and18connected to the tongue portion14with a pair of connectors20and22, respectively. A generally curved end flange24is connected to the side portions16and18and extends along the rear of the tongue plate12. The outer edge of the end flange24typically has a contour as shown clearly inFIG. 2.

The tongue portion14is provided with a latch aperture26, and the rear of the tongue portion14, the connectors20and22, the side portions16and18, and the end flange24surround a second aperture28. The primary purpose of the second aperture28is for weight reduction of the locking tongue10. A flange30with a slot32extends generally along the length of the side portion16, and a flange34with a slot36is located on the other side of the tongue plate12and extends generally along the length of the side portion18. The flanges30and34extend away from the side portions16and18so that they are generally positioned at right angles relative to the plane of the side portions16and18.

The locking tongue10further includes an elongated lock bar38. One end of the lock bar38resides in the slot32, and the other end resides in the slot36. A sleeve40encompasses most of the lock bar38and is typically a molded component that encapsulates the lock bar38. The contour of the sleeve40generally matches the contour of edge the end flange24so that tension in a seat belt webbing is distributed across the width of the webbing when it is cinched between the sleeve40and the end flange24as described below in more detail.

As shown more clearly inFIGS. 4 and 5, the slot36includes an enlarged section42and a narrow section44. The slot32on the other side of the tongue plate12has similar enlarged and narrow sections46and48(FIGS. 6 and 7), respectively, such that the ends of the lock bar38are able to slide along the slots32and36between the enlarged and narrow sections of each slot32and36depending on the load applied to the seat belt webbing.

Referring in particular toFIG. 4, the lock bar38is shown situated in the narrow portion44in a locked position, whereas inFIG. 5, the lock bar38is shown situated in the enlarged section42in an unlocked position. Note that as the ends of the lock bar38slide along the slots32and36from the locked position (FIG. 4) to the unlocked position (FIG. 5), the lock bar38slightly rotates (counterclockwise in these views) about its longitudinal axis, and, of course, the lock bar38rotates in the opposite direction when it moves from the unlocked position to the locked position.

The locking tongue10is suitable for use in both two point and three point seat belt systems.FIGS. 6 and 7show the locking tongue10in use with a seat belt webbing50with a leading section54and a trailing section52situated between the sleeve40and the end flange24. When the locking tongue10is in use, the occupant typically grabs the locking tongue10and inserts the tongue portion14into a buckle to secure the locking tongue10and the buckle together. While this occurs, the leading section54loops underneath the sleeve40and hence the lock bar38as shown inFIG. 6.

After the locking tongue10and the buckle are secured together, a sudden deceleration of the vehicle will result in the lock bar38to move to the locked position. In such a situation, the ends of the lock bar38slide along the slots32and36from the enlarged sections46and42to the narrow sections48and44. During the sliding movement of the lock bar38into the locked position, the lock bar38slightly rotates as illustrated by the position of the lock bar38inFIGS. 6 and 7.

When the lock bar38is in the locked position (FIG. 6), the seat belt webbing50is cinched between the sleeve40and the outer edge of the curved end flange24. As stated previously, the region of the sleeve40that cinches the webbing50against the edge of the end flange24has a contour that generally matches the profile of the contour of the edge of the end flange24to distribute the tension in the seat belt webbing50across the width of the webbing to reduce the potential for web tearing.

After use of the locking tongue10is no longer required, for example, when the occupant is ready to disembark from the vehicle, the occupant releases the tongue portion14from the buckle. In particular arrangements, a retractor retrieves the trailing section52of the seat belt webbing50. As this occurs, the leading section54of the webbing50unwraps from underneath the sleeve40and hence the lock bar38(FIG. 7) so that the seat belt webbing50is oriented generally vertically, for example, in a three point seat belt system. Further, the lock bar38moves into the unlocked position, that is, the ends of the lock bar38move from the narrow sections44and48of the respective slots36and32to the enlarged sections42and46so that the seat belt webbing50is no longer cinched between the sleeve40and the end flange24. The locking tongue10is then able to slide freely along the seat belt webbing50toward the leading section54when the seat belt webbing50has a general vertical orientation. In some implementations, a spring element is used to bias the lock bar38in the unlocked position.