GB2119005A - Belt length adjustment device - Google Patents

Abstract

The device consists of a frame 8, having spaced parallel bars 14, 16 around which a belt 4 is entrained, and a member 2 having a slot 6. The frame 8 is receivable in the slot 26 by virtue of its side brackets 12 being resiliently deformable and is retained in the slot by lugs 22. The frame 8 is pivotable in the slot 6 about a line of contact between a plate portion 10 of the frame and the surface of the member 2. A pull on the belt 4 at an angle to a plane perpendicular to the plane of the slot of less than o results in the belt moving freely through the device. However, when the angle o is exceeded the frame 8 pivots in the slot 6 and the belt 4 is snubbed at 28 and 29 (see figure 3) between the bars 14, 16 and the edges of the slot 6. The member 2 may be a part of a child's vehicle safety seat, a part of a releasable buckle, or a part of a belt- length adjuster. <IMAGE>

Description

SPECIFICATION Belt length adjustment device The invention relates to a belt length adjustment device.

Belt length adjustment devices are used for example in safety systems for vehicle occupants to permit selective adjustment of the length of a belt extending between, say, a fixed anchorage position and another element of the system for example a childs seat or one part of a two-part buckle.

It is desirable that such adjustment devices be simple, inexpensive to manufacture, that they afford smooth and easy adjustment in either direction of the belt, and that they lock the belt securely under a load in a predetermined direction.

The invention accordingly provides a belt length adjustment device comprising a first member having a slot through which the belt extends, a second member capable of pivotation relative to the first member and engaged by the belt, the belt being freely movable through the slot in response to pulls thereon in a first direction, but being snubbed between the second member and an edge of the slot by the pivotation of the second member in response to a load on the belt in a second direction.

The second member can comprise a frame mounting two spaced parallel bars round which the belt is entrained, the frame being pivotally mounted in the slot in the first member. Preferably the arrangement is such that the belt is snubbed between each of the bars and a respective edge of the slot. The frame carrying the two bars can have a plate portion extending transversely of the plane in which lie the arcs of the two bars and normally lying adjacent one side of the first member, the position at which the edge of the plate portion engages the first member defining the axis about which the frame pivots.

The invention is further described below, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a belt length adjustment device embodying the invention, incorporated in a childs seat for use in a vehicle, with various portions thereof shown spaced apart and broken away; Figure 2 is a sectional side view of the device of Figure 1 in a position in which the belt length is freely adjustable; Figure 3 is a view similar to that of Figure 2, but showing the device in a position in which the belt is snubbed against extension; Figures 4 and 5 resemble Figures 1 and 2, but show the device in a different context of use; and Figures 6A and 6B show in perspective respective modifications of the device of Figures 4 and 5.

In Figures 1, 2 and 3, the illustrated belt length adjustment device is shown incorporated in a child's seat for use in a vehicle, the seat comprising a moulded plastics shell 2. The shell 2 is secured in place in a vehicle seat by an appropriate system of straps and has secured to it a harness by which an occupant is releasably held seated in the shell. The harness comprises a plurality of straps 4 and the way in which one of these is connected to the shell appears from Figures 1 to 3.

The belt 4 extends through an aperture 6 in a generally upright portion of the shell. In this aperture is received a frame 8, conveniently of plastics material, which comprises a generally rectangular centrally apertured plate-like portion 10 having a pair of brackets 12 extending parallel to each other from the shorter sides. Parallel first and second bars 14, 1 6 in the form of rods of circular cross-section extend respectively between the shorter sides of the portion 10 and between the free ends of the brackets 12.

The aperture 6 in the shell 2 is generally Hshaped, with a parallel sided central portion defined by edges 18, and of sufficient breadth to accommodate the belt 4, and end portions 20 of greater extent in the direction at right angles to the belt. The brackets 12 of the frame are received in the end portions 20 as shown in Figures 2 and 3, with the bars 1 4, 1 6 on opposed sides of the shell 2. The frame 8 is held assembled with the shell by means of external projections 22 at the free ends of the brackets 12. The projections 22 have an abutment face towards the portion 10 which is parallel to the plane of this portion and are smoothly tapered to this face from the free ends of the brackets, so that the frame can be readily assembled with the shell, because of the resilience of both the frame 8 and the shell 2.The spacing of the projections 22 and the plate like portion 10 is greater than the thickness of the shell 2 so that, as shown in Figure 3, the frame 8 is free to pivot in the aperture 6 relative to the shell.

In use the belt 4 is required to resist loads applied in any direction having an angle greater than (Figure 3) to the horizontal plane 24 through the device. The belt is however required to be freely adjustable in length in response to pulls below the plane 24 on the same side of the shell, as indicated by arrows 25 in Figure 1, and pulls on from the other side of the shell indicated by arrows 26 in Figure 1. The belt accordingly extends from its unloaded end aperture in the plate-like portion 10 of the frame and then through the aperture 6 over the bars 14, 1 6 to the other side of the shell, around the bar 1 6, back around the bar 14 and then underneath the bars to its loaded end. The belt 4 thus extends three times through the adjustment device.

From Figure 2 it will be seen that pulls on the belt 4 in any of the directions indicated by the arrows 25, 26 will encounter no substantial resistance, beyond the frictional resistance experienced in movement of the belt around the bars 14, 1 6. The belt acts on neither of the bars but on either the upper or the lower edge 1 8 of the slot 6. The frame 8 moves slightly with the belt between the limits set by engagement with the shell 2 of the projections 22 and the frame portion 10. The length of the belt can thus be readily adjusted, and the frame experiences no force tending to tilt it.

However, if the belt 4 is now pulled in any of the directions indicated by the arrows in Figure 3, the belt acts immediately on the bar 16 to tend to cause the frame to tilt in the clockwise direction, as illustrated. The lower longer edge of the plate like portion 10 abuts against the shell 2, and both bars 14 and 1 6 translate about the axis defined by this abutment line to clamp the portions of the belt entrained about them against the edges 1 8 at respective positions 28, 29. The belt 4 is thus securely held against movement by a double snubbing action. On release of the load represented by the arrows in Figure 3, the frame 8 is immediately freed to return to the position of Figure 2 in which belt length adjustment can be readily effected.

The belt length adjustment device of the invention is shown embodied a conventional belt length adjuster in Figures 4 and 5, in which figures parts similar to those of Figures 1 to 3 are given the reference numerals used in those figures. The frame 8 is received in an aperture 6, not in a plastics moulded shell, but in a flat, generally rectangular, metal plate 102 which is apertured also at 104 to receive a second belt 105 by which the plate is connected to an anchorage.

The operation of the device of Figures 4 and 5 is precisely the same as that of Figures 1 to 3.

Note however that the situation is not that of the device as shown in Figure 2 turned anticlockwise through 900; the belt 4 is received through the frame portion 10 on the other side of the bar 14.

The device is consequently able to resist loading in the direction indicated at 107 and it can be shortened by a pull in the direction indicated at 108, and lengthened by a pull in the direction indicated at 109.

The plate 102 can be modified to constitute one part of a two-part buckle, as shown in Figures 6A and 6B, by replacing the end with the aperture 104 by a tongue 110 having either a pair of latching edges 111, as shown in Figure 6A, or a single latching edge 112, as shown in Figure 6B.

The plate 102 can then co-operate with buckle socket parts such as are described in Patent Publication GB 2 027 790 (Case KL 83/4) for I example.

It will be evident from the foregoing that devices embodying the invention can be used in a variety of different situations, and not only in vehicle safety systems, but wherever a belt or other flexible elongate element has to be adjustably held against a load. Moreover, the particular embodiments illustrated and described can be modified in a variety of ways, for example, as regards the belt configuration through the device and the way in which the pivotation to affect snubbing is provided for.

Claims (12)

1. A device for length adjustment of an elongate element, the device comprising a first member having an aperture through which the element extends from one side of the device to the other, and a second member capable of pivotation relative to the first member and through which the elongate element is entrained in a manner such that the elongate element is freely movable through the aperture in response to a pull thereon in a first direction from one side of the first member but is snubbed between the second member and an edge of the aperture by pivotation of the second member in response to a pull thereon in a second direction from the said one side of the first member.

2. A device according to claim 1, in which the elongate element is snubbed between first and second snubbing surfaces of the second member and respective diagonally-opposed edges of the aperture.

3. A device according to claim 2, in which the- second member has two spaced parallel bars around which the elongate element is entrained and the aperture is a slot extending in the direction of the bars, the first and second snubbing surfaces being portions of the surfaces of the respective bars.

4. A device according to claim 3, in which the direction of the elongate element is reversed around each of the bars.

5. A device for length adjustment of an elongate element, the device comprising a first member having a slot therethrough, and a second member having first and second bars about each of which the elongate element reverses its direction, the second member being pivotable relative to the first member in response to a pull in a predetermined direction to snub the elongate element between one of the bars and an edge of the slot.

6. A device according to any one of the claims 3 to 5; in which the bars are mounted on a frame portion of the second member and the frame portion is receivable in the slot for pivotation of the second member relative to the first member.

7. A device according to claim 6, in which the frame portion comprises respective brackets supporting the ends of the bars and the slot has respective transverse end portions for receiving the brackets of the frame portion.

8. A device according to claims 6 or 7, in which the frame portion of the second member includes a plate portion which extends transversely of the plane of the axis of the two bars and, when the second member is received in the slot, lies adjacent one face of the first member, the position at which the edge of the plate portion engages the first member defining the axis of pivotation of the second member

9. A device according to any preceding claim, in which a least part of the second member is resiliently deformable to allow its reception in and demounting from the slot or aperture.

10. A device according to any preceding claim, in which the first member is one part of a releasable buckle.

11. A device according to any one of claims 1 to 9, in which the first member is a portion of a vehicle safety seat for a child.

12. A belt length adjustment device substantially as hereinbefore described with reference to any figure of the drawings.