GB1601104A

GB1601104A - Safety restraint apparatus

Info

Publication number: GB1601104A
Application number: GB1135777A
Authority: GB
Original assignee: Britax Wingard Ltd
Current assignee: SMR Automotive Mirrors UK Ltd
Priority date: 1977-03-17
Filing date: 1977-03-17
Publication date: 1981-10-28
Also published as: FR2383677B3; FR2383677A1

Description

(54) SAFETY RESTRAINT APPARATUS (71) We, BRITAX (WINGARD) LIMITED formerly WINGARD LIMITED a British Company of Chandler Road, Chichester, Sussex, Pro 19 2UG, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to safety restraint apparatus and more particularly, to a device which reduces excess pay out of a safety belt in accident conditions.

The invention may be applied, for example, to the type of safety apparatus wherein a safety belt is stored on a reel which is locked by an inertia or belt acceleration responsive device under accident conditions. In such apparatus, the belt is usually paid out from the reel against the bias of a rewinding spring. The torque exerted by the spring must not be too high as this would cause discomfort when the belt is tensioned across the user's torso. However, if the spring torque is reduced to improve comfort, it may mean that the end of the belt is not tightly stored on the reel when retracted by the spring. Even when the belt is pulled off the reel to be fastened about the wearer's torso, a certain length is retracted after the major portion has been fastened. Moreover, there is usually a length of belt stored on the reel for accommodating large body sizes. If the belt, when worn, has an end portion which is not tightly stored on the reel, then when the reel is locked, under accident conditions, the sudden tension exerted on the belt may cause a certain length (for example, 5 centimetres) to be extracted from the reel as the turns of the end portion are tightened. Moreover, the belt, which is typically made of webbing, may stretch when such tension is applied. In both cases, this leads to an excess pay out of belt which enables the belt user to move forward, under accident conditions, even when the reel is locked, and this is particularly disadvantageous in small vehicles.

The disadvantage of excess belt pay out under accident conditions may be more apparent in reel locking devices which include a mechanism for reducing the torque when the belt is worn. Moreover, the same disadvantage could apply in other forms of safety restraint apparatus which may, or may not employ locking reels.

Safety restraint apparatus, such as the socalled 'inertial locking reel' are expensive to manufacture at least, in part, because they are designed to withstand the loads imposed by a restrained passenger under accident conditions.

It would therefore be advantageous to employ a device which relieves the load imposed on the reel locking mechanism so that the mechanism may be of a less expensive design.

The present invention seeks to mitigate these problems by providing a device for reducing excess pay out of a safety belt under accident conditions, the device comprising entrainment means through which the belt can be looped and a blocking member which is displaceable into a blocking position in which the belt is secured in the entrainment means, the blocking member being held out of its blocking position by deformable means which deforms to allow the blocking member to move into its blocking position, under a predetermined belt tension, and thereafter inhibits movement of the blocking member out of its blocking position.

The invention also provides safety restraint apparatus comprising a safety belt, means for paying out the safety belt, means for preventing pay out of the safety belt under accident conditions, means for releasably securing the belt to an anchorage point and a device interposed between said belt pay out means and said belt securing means for reducing excess belt pay out under accident conditions, said device comprising entrainment means through which the belt can be looped and a blocking member which is displaceable into a blocking position in which the belt is secured in the entrainment means, the blocking member being held out of its blocking position by deformable means which deforms to allow the blocking member to move into its blocking position, under a predetermined belt tension, and thereafter inhibits movement of the blocking member out of its blocking position.

When the device for reducing excess pay out of a safety belt is interposed between, on the one hand a belt retractor such as an inertia locking reel, and on the other hand a belt fastener such as a tongue and buckle in a loop of a lap and diagonal harness, it reduces the excess belt pay out, when the reel is locked, due to tightening of the turns of the belt on the reel and stretching of the belt material. In a conventional arrangement, the inertia reel is normally mounted at, or close to the floor level of a vehicle and a length of said belt is led from the reel to a running loop, usually on the door pillar and then down to form the diagonal portion of the harness. The running loop may be modified, according to the invention, conveniently to provide the device for reducing excess belt pay out. The device therefore acts as a load sensitive belt or webbing lock at the loop wherein (a) upon sudden deceleration, the inertia reel locks, (b) the occupant starts to move forwards, (c) the combination of the locked reel and occupant movement causes tension to be exerted in the belt or webbing, and (d) the webbing tension actuates the lock at the pillar loop.

The invention may be embodied in various ways as broadly described below and more specifically described with reference to the accompanying drawings.

In one embodiment, the belt is entrained about a member in the form of a sliding loop, the sliding action causing the belt to be clamped between the loop and a base frame.

The loop may be substantially U-shaped and sprung into corresponding arms or recesses in the base frame, the arrangement being such that the loop is displaced from its location in the recesses or arms so as to move towards an abutment portion of the base frame. The abutment portion is preferably in the form of a divided wall having portions attached to respective arms on the base frame. This enables the belt to be slipped between the division and entrained about the U-shaped loop which is then located by recesses and projections in the arms of said frame.

The embodiments of the invention are more specifically described with reference to the accompanying drawings in which: Figures 1 and 2 illustrate a first embodiment with a displaceable loop member.

In the embodiment of Figures 1 and 2, a base frame 1 made of sheet metal has a pair of arms 1' which are folded across the front of the frame and which terminate in abutment faces or walls 5 separated by a space 5'. A U-shaped member in the form of a wire loop 3 has its ends turned down and each end has a raised portion 4 which projects into a hole 2 in the respective arm 1' of the frame 1. The faces 5 support a length of webbing 6 which is entrained about the wire loop 3. A pair of plastics shoulders 3' serve to guide the webbing 6 to prevent lateral movement towards the sides of the loop 3. When a predetermined tension is exceeded in the webbing 6, for example, when an inertia reel locks in an accident condition and the occupant moves forwardly off his seat due to momentum, the loop 3 is urged downwardly so that the projections 4 are cammed out of the locating holes 2. The legs of the loop 3, on which projections 4 are formed, flex inwardly (to permit deformation of the loop) to enable the projections 4 to be cammed out of holes 2. The loop 3 then moves rapidly to a blocking position where it clamps or jams the webbing between the loop and the faces 5. In this position, the loop 3 is still deformed, due to the inward flexure of its legs, and thus it acts to inhibit movement of the loop out of its blocking position. Thus, the loop 3 cannot easily be returned to its initial position and this indicates that the belt has been used in a severe accident condition. After the belt has been wedged or jammed between the loop 3 and the faces 5, the increase in the applied load is not applied to the remote end of the webbing, for example, to a storage reel, but only to the locked loop 3. Therefore, an inertia reel, or its equivalent at the remote end portion of the webbing, may be more lightly constructed than is conventionally the case.

WHAT WE CLAIM IS: 1. A device for reducing excess pay out of a safety belt under accident conditions, the device comprising entrainment means through which the belt can be looped and a blocking member which is displaceable into a blocking position in which the belt is secured in the entrainment means, the blocking member being held out of its blocking position by deformable means which deforms to allow the blocking member to move into its blocking position, under a predetermined belt tension, and thereafter inhibits movement of the blocking member out of its blocking position.

2. Safety restraint apparatus comprising a safety belt, means for paying out the safety belt, means for preventing pay out of the safety belt under accident conditions, means for releasably securing the belt to an anchorage point and a device interposed between said belt pay out means and said belt securing means for reducing excess belt pay out under accident conditions, said device comprising entrainment means through which the belt can be looped and a blocking member which is displaceable into a blocking position in which the belt is secured in the entrainment means, the blocking member being held out of its blocking position by deformable means which deforms to allow the blocking member to move into its blocking position, under a predetermined belt tension, and thereafter inhibits movement of the blocking member out of its blocking position.

3. Apparatus according to claim 2 wherein said means for paying out the belt comprises a belt retractor including an inertia locking reel mechanism, and wherein said means for releasably securing the belt comprises a tongue and buckle in a loop of a lap and diagonal portion of the belt.

4. Safety restraint apparatus according to claim 3 wherein said retractor is mounted at, or

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. excess belt pay out, when the reel is locked, due to tightening of the turns of the belt on the reel and stretching of the belt material. In a conventional arrangement, the inertia reel is normally mounted at, or close to the floor level of a vehicle and a length of said belt is led from the reel to a running loop, usually on the door pillar and then down to form the diagonal portion of the harness. The running loop may be modified, according to the invention, conveniently to provide the device for reducing excess belt pay out. The device therefore acts as a load sensitive belt or webbing lock at the loop wherein (a) upon sudden deceleration, the inertia reel locks, (b) the occupant starts to move forwards, (c) the combination of the locked reel and occupant movement causes tension to be exerted in the belt or webbing, and (d) the webbing tension actuates the lock at the pillar loop. The invention may be embodied in various ways as broadly described below and more specifically described with reference to the accompanying drawings. In one embodiment, the belt is entrained about a member in the form of a sliding loop, the sliding action causing the belt to be clamped between the loop and a base frame. The loop may be substantially U-shaped and sprung into corresponding arms or recesses in the base frame, the arrangement being such that the loop is displaced from its location in the recesses or arms so as to move towards an abutment portion of the base frame. The abutment portion is preferably in the form of a divided wall having portions attached to respective arms on the base frame. This enables the belt to be slipped between the division and entrained about the U-shaped loop which is then located by recesses and projections in the arms of said frame. The embodiments of the invention are more specifically described with reference to the accompanying drawings in which: Figures 1 and 2 illustrate a first embodiment with a displaceable loop member. In the embodiment of Figures 1 and 2, a base frame 1 made of sheet metal has a pair of arms 1' which are folded across the front of the frame and which terminate in abutment faces or walls 5 separated by a space 5'. A U-shaped member in the form of a wire loop 3 has its ends turned down and each end has a raised portion 4 which projects into a hole 2 in the respective arm 1' of the frame 1. The faces 5 support a length of webbing 6 which is entrained about the wire loop 3. A pair of plastics shoulders 3' serve to guide the webbing 6 to prevent lateral movement towards the sides of the loop 3. When a predetermined tension is exceeded in the webbing 6, for example, when an inertia reel locks in an accident condition and the occupant moves forwardly off his seat due to momentum, the loop 3 is urged downwardly so that the projections 4 are cammed out of the locating holes 2. The legs of the loop 3, on which projections 4 are formed, flex inwardly (to permit deformation of the loop) to enable the projections 4 to be cammed out of holes 2. The loop 3 then moves rapidly to a blocking position where it clamps or jams the webbing between the loop and the faces 5. In this position, the loop 3 is still deformed, due to the inward flexure of its legs, and thus it acts to inhibit movement of the loop out of its blocking position. Thus, the loop 3 cannot easily be returned to its initial position and this indicates that the belt has been used in a severe accident condition. After the belt has been wedged or jammed between the loop 3 and the faces 5, the increase in the applied load is not applied to the remote end of the webbing, for example, to a storage reel, but only to the locked loop 3. Therefore, an inertia reel, or its equivalent at the remote end portion of the webbing, may be more lightly constructed than is conventionally the case. WHAT WE CLAIM IS:

1. A device for reducing excess pay out of a safety belt under accident conditions, the device comprising entrainment means through which the belt can be looped and a blocking member which is displaceable into a blocking position in which the belt is secured in the entrainment means, the blocking member being held out of its blocking position by deformable means which deforms to allow the blocking member to move into its blocking position, under a predetermined belt tension, and thereafter inhibits movement of the blocking member out of its blocking position.

close to the floor level of a vehicle and a length of said belt is led from the reel to said device, which is fitted to the door pillar of the vehicle, and then down to form the diagonal portion of the harness.

5. A device according to claim 1 or apparatus according to any one of claims 2-4 wherein said blocking member comprises a sliding loop mounted on a base frame, the sliding action causing the belt to be clamped between the loop and a base frame.

6. A device or apparatus according to claim 5 wherein the loop is substantially U-shaped and is sprung into corresponding arms or recesses in the base frame, the arrangement being such that the loop is displaced from its location in the recesses or arms so as to move towards an abutment portion of the base frame.

7. A device according to claim 1, or apparatus according to any one of claims 2-6, wherein said device is substantially as herein described with reference to the accompanying drawings.