# US 4,393,554 A · Locking device for safety belts

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- Number: US 4,393,554 A
- Document ID: US4393554A
- Status: Granted
- Kind: A
- Application number: 06/237,922
- Filed: 1981-02-25
- Granted: 1983-07-19
- Earliest claimed: 1980-02-25
- Assignees: Repa Feinstanzwerk GmbH
- Inventors: Franz Wier
- Web page: https://patentgrep.com/patent/US4393554A

## CPC

- A44B 11/2523: {acting parallel to the main plane of the buckle and in the same direction as the fastening action}
- Y10T 24/45723: having slidably connected, nonself-biasing interlocking component
- A44B: BUTTONS, PINS, BUCKLES, SLIDE FASTENERS, OR THE LIKE (fastenings specially adapted for footwear A43C)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Locking device for a safety belt with a belt lock and a plug-in tongue fastened to the belt end. The tongue can be engaged with an engagement edge by at least one latch which is movable transversely to the plug-in direction of the plug-in tongue. The latch in the region of the engagement edge of the plug-in tongue has a profile which comes close to complementing the shape of the engagement edge as it changes under load.

## Claims

### Claim 1

Locking device for a safety belt comprising a belt lock having two spaced plates defining an insertion path, a plug-in tongue attached to a belt for insertion in the insertion path, a latching bolt having an engagement surface movable transversely to the plug-in direction of the plug-in tongue to block withdrawal of the tongue by contact of said engagement surface with a straight edge surface of said plug-in tongue, said straight edge surface changing its shape upon the belt being subjected to a load and said engagement surface of said latch contoured to complement the shape of said edge surface under load to thereby provide increased contact area between said latching bolt and said plug-in tongue under load conditions.

### Claim 2 (depends on 1)

Locking device according to claim 1, wherein the tongue has a detention opening with a single, straight engagement edge, and wherein the latch has an arched profile as the surface in contact with the edge surface of the plug-in tongue.

### Claim 3 (depends on 1)

Locking device according to claim 1, wherein the tongue has a T-shape, and wherein the latch has two wedge-shaped profiles arranged at both sides of the tongues as the surfaces in contact with the edge surfaces of the plug-in tongue.