GB1596307A

GB1596307A - Safety belt fitted with webbing cutter

Info

Publication number: GB1596307A
Application number: GB32932/77A
Authority: GB
Original assignee: Britax Wingard Ltd
Current assignee: SMR Automotive Mirrors UK Ltd
Priority date: 1978-05-31
Filing date: 1978-05-31
Publication date: 1981-08-26
Also published as: IT7849600A0; IT1104699B

Description

(54) SAFETY BELT FITTED WITH WEBBING CUTTER (71) We, BRITAX (WINGARD) LIMITED, a British Company of Chandler Road, Chichester, Sussex, PO19 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 a safety belt which is fitted with a webbing cutter which is used to cut through the safety belt, in an emergency, to release a vehicle occupant.

Nowadays, most vehicles are fitted with safety belts as a sensible precaution in reducing the risk of injury to a seated occupant in accident conditions. Whiist safety belts reduce the risk of injury, there are exceptional circumstances when a seated occupant must be released from a safety belt by another person, for example, in an emergency when the occupant is unconscious and the vehicle is on fire. In some cases, the vehicle body may have been deformed by impact thus adding to the difficulty of releasing the occupant from the fastened safety belt. Therefore, there is a need to provide same means for releasing a safety belt in an emergency. One approach is to provide some form of webbing cutter so that the belt can be severed in an emergency.

However, the severing of a safety belt presents at least the following practical problems: (a) webbing is very tough material to cut as it is composed of very closely woven and strong fibres, (b) the cutting of webbing is made difficult, or impossible if the edge of the webbing curls or bends up against a cutting edge, (c) the webbing cutter must not be capable of ineffective use, for example, it must not just nick the webbing of a safety belt because the belt would then be unsafe and uncapable of further use, (d) accidental operation, or operation by inquisitive children of the webbing cutter for a safety belt must be made unlikely or difficut.

The present invention seeks to overcome these problems by providing a safety belt fitted with a webbing cutting device, the cutting device comprising at least one cutter mounted on a webbing supDort, which is adapted to support a length of webbing forming part of said belt, relative to the or each cutter, which is located in a storage position out of contact with said webbing, and means being provided to cause relative displacement between the the cutter or cutters and the webbing to sever the webbing.

Preferably, the support includes at least one edge which provides a cutting support for the cutter and suitably the edge is defined by an aperture or slot in the support.

Preferably, the or each cutter is displaceable across the webbing with respect to the webbing support. Alternatively, the webbing is displaceable with respect to a fixed cutter or cutters in said support. In one preferred embodiment of the invention, the or each cutter comprises a member which is preloaded in the storage position whereby it automatically traverses the support to sever the webbing when displaced from the storage position. The preloading is suitably effected by the energy stored in a spring. A pair of pre-loaded cutters can be provided which are displaceable so as to penertate the webbing and subsequently move apart due to the spring, to sever the webbing. Preferably, the preloaded cutters are the sharpened end portions of a coil spring mounted on the support, the end portions normally being located in a storage slot and being displaceable into a cutting slot after penetrating the webbing. The end portions spring apart in the cutting slot to sever the webbing.

The or each cutter may be displaceable in directions which are both perpendicular and transverse to the plane of the webbing. This enables the or each cutter to cut the webbing in the usual manner of a knife. However, the or each cutter may also be displaceable in a direction which is just transverse to the plane of the webbing. In the latter case, the or each cutter may have a straight, concave, crescent or arcuately shaped cutting edge. According to another arrangement, at least one of said cutters is displaceable relative to another one of said cutters so as to perform a shearing action.

Leverage may be employed to facilitate displacement of the or each cutter to sever the webbing.

The support may be of channel section having a flat floor extending between opposite sidewalls, the length of webbing being received on the floor and the floor including at least one edge which provides a cutting support for the cutter. Suitably, the floor has an aperture or slot extending transversely of the length of webbing between the sidewalls, the cutter or cutters being displaceable in the aperture or slot to sever the webbing. The cutter or cutters can be mounted on a bridge fitted to, or integral with the channel section support.

According to another embodiment of the invention, the support has an opening therethrough receiving the webbing, the support being fitted to the webbing, in the manner of a sliding buckle, the support having a slot which extends transversely of the opening and in which the or each cutter is displaceable to sever the webbing.

The invention may also be embodied as described below.

A cutter is provided in the form of a blade located in a storage slot in said support, the blade has a chamfered edge, and the means for causing relative displacement comprises a member mounted for transverse movement along the storage slot so as to engage the chamfered edge of the blade and cause it to move obliquely towards the webbing.

A cutter is provided in the form of a circular blade located in a storge slot in the support and the means for causing relative displacement is a member for urging the cutting blade across the storage slot to sever the webbing.

A cutter is provided in the form of a blade mounted for movement towards the webbing and the means for causing relative displacement comprises a lever with a cam portion for engaging and urging the blade towards the webbing.

The support defines a recess bounded by shoulder portions on which the webbing is supported, the recess contains a blade on one side of the webbing and the means for causing relative displacement comprises a member on the other side of the webbing and which can be urged towards the blade.

A cutter is provided in the form of a blade mounted for movement towards the webbing and the means for causing relative displacement comprises a lever connected by a toggle link or links to the blade for urging it towards the webbing.

Cutters are provided in the form of a fixed blade and a moveable blade pivotally mounted on the fixed blade, the webbing being received between said blades. The means for causing relative displacement causes the moveable blade to move towards the fixed blade to shear the webbing.

A cutter is provided in the form of a blade located in a slot in the support, the blade normally being located in a storage position at one end of the slot and the means for causing relative displacement is used to urge the blade along the slot to sever the webbing.

Although the invention is generally directed to a safety belt having a webbing cutting device, this specification may provide the basis for divisional applications which independently protect the webbing cutting devices, per se, described herein. In the letter respect, the webbing cutting devices are considered independently of the safety belt.

Embodiments of the invention will now be described with reference to the accompanying drawings in which: Fig. 1 is a perspective view of an experimental rig for investigating the cutting of a length of webbing, Fig. 2 is a schematic elevation for explaining the problem relating to the cutting of a length of webbing, Fig. 3 is a perspective view of a webbing cutter according to a first embodement of the invention, Fig. 4 is a detailed view of a pair of cutting edges used in the first embodiment.

Fig. 5 is a perspective view of a webbing cutter according to a second embodiment, Fig. 6 is a sectional view of the second embodiment, Fig. 7 is a perspective view of a webbing cutter according to a third embodiment, Fig. 8 is a sectional view of the third embodiment, Fig. 9 is a perspective view of a fourth embodiment, Fig. 10 is a sectional view of the fourth embodiment, Fig. 11 is a perspective view of a fifth embodiment, Fig. 12 is a perspective view of a sixth embodiment, Fig. 13 is a sectional view of the sixth embodiment, Fig. 14 is a perspective view of a seventh embodiment, Fig. 15 is a sectional view through the seventh embodiment, Fig. 16 is a perspective view of an eighth embodiment, Fig. 17 is a sectional view of the eighth embodiment, and Figs. 18-21 are views of a ninth embodiment.

Webbing can be cut easily by a sharp blade if the area to be cut is carefully sup ported against a cutting edge to stop the webbing from bending or curling against the direction of cutting. Fig. 1 is provided to illustrate an experiment wherein a length of webbing W is supported on a pair of blocks 1 2 which are spaced by a gap 3 which is just wide enough for the insertion of the cutting edge of a cutting member 4. When the webbing is held taut, it can be cut with a single stroke of member 4. However, the main problem encountered in cutting the webbing is best understood with regard to Fig. 2 wherein the lateral edge portion of the webbing W is shown curled up against the direction of movement of the cutting member 4 making it impossible to start the cut.

Fig. 3 illustrate a preferred embodiment of the invention. A length of webbing W is received in a support 6 having a shallow, U-shaped cross section. Support 6 has a floor 7 extending between upstanding walls 8, 9. A narrow slot 10 is provided in the floor 7, the slot extending between the walls 8, 9. The support 6 may be made of plastics material.

A mounting 11, which may be made of metal, forms a lid for part of the U-shaped section of support 6. The mounting 11 may be located by slotted shoulder portions 12 and 13, which are pressed in the edges of the metal mounting 11 and which receive outwardly directed edge portions 14 15 of the respective walls 8, 9 of the support 6. A downturned edge portion 16 of the mounting 11 includes a slot 17. A boss 18 projects upwardly from the upper surface of mounting 11.

The mounting 11 is provided for supporting a coil spring 19. The coils of the spring are located by boss 18. The end portions of the spring form respective arms 20, 21 which are normally received in slot 17 and which have downturned parts 22, 23 which are sharpened to form cutting edges. Fig. 4 illustrates the end parts 22, 23 in greater detail, these parts being flattened or ground flat in the plane of the paper to form cutting edges 24, 25 which extend in opposite directions with respect to the longitudinal axis of slot 10.

An emergency release button 26 is joined to a shank 27 passing through an aperture in the upper surface of mounting 11. Shank 27 is joined to an abutment member 28 which extends transversely across the arms 20, 21 when received in the slot 17. As illustarted in Fig. 3, the arms 20, 21 are normally held in tightly abutting relationship in, and by the edges of slot 17. In this position, the shank 27 extends through its aperture so that the push button 26 is clear of the upper surface of mounting 11.

The device shown in Fig. 3 may be mounted on a length of webbing W forming a safety belt and at a position wherein its operation will not injure the vehicle occupant. In an emergency, to release the vehicle occupant from the safety belt, the button 26 is forcibly struck to drive the arms 20, 21 out of their storage slot 17 so that the cutting edges 24, 25 pierce the webbing W and then spring apart in the slot 10 to sever the webbing.

As the cutting edges must remain sharp even after several years from installation, they may be made of stainless material, or lightly greased or varnished at the time of manufacture, to reduce or eliminate corrosion.

Figs. 5 and 6 show a further embodiment of the invention wherein the webbing cutter comprises a body 30 having an aperture 31 therethrough for receiving webbing 32. A cutting blade 33 is normally maintained in the storage position, for example, by frictional engagement with a corresponding slot or slit (not shown) in the body 30, with its cutting edge 35 clear of the webbing 32. A corner 36 of the blade 33 is chamfered as shown in Fig. 6 to provide a storage position, at the end of a slot 37, for the end 38 of a wire handle 39. The handle 39 is pulled in the direction of arrow 40 whereby the end 38 rides over the chamfer 36 thereby forcing the cutting edge 35 towards the webbing 32.

The webbing is severed after the handle 40 has been drawn across most of the width of slot 37.

The embodiment of Figs. 7 and 8 has a similar action with the main exception of using a cutting wheel 42 instead of a blade 33. The wheel 42 is rotatably mounted at one end 43 of a wire handle 44. The wheel is supported in a continuous slot 45 extending about the periphery of a slot 46 through a webbing support 47. A length of webbing 48 extends through slot 46 and is severed when the wire handle 44 is drawn in the direction of arrow 49.

Figs. 9 and 10 show a further embodiment having the action of a guillotine. In this case, a handle 51 has a cam-shaped end 52 supported on pivots 53, 54 mounted between spaced arms 55, 56. The arms 55, 56 extend from a support 57. A cutting blade 58 is mounted in a holder 59 which is supported, at each end, in a pair of spaced guides 60 (only one of which is shown in Fig. 9) for movement in a vertical direction towards the width of a length of webbing 61. The cutting edge 58 may, in this case, be urged towards the flat surface of the support 57, (as shown in Fig. 10). However, the support 57 may be modified by defining an edge, slot or aperture to provide a cutting support for the blade 58 when it is urged towards the webbing 61. The handle 51 is lifted in the direction of arrow 62 (Fig. 10) whereby the cam 52 urges the blade 58 towards the web bing 61.

In the simplified embodiment of Fig. 11, a pressure plate 64 is supported (by means not shown) above a shallow depression 65 and a cutting edge 66 in a support 67. A length of webbing 68 is entrained between the pressure plate 64 and the support 67.

The pressure plate includes a push button 69 which is depressed to urge the webbing 68 against the cutting edge of blade 66. As in the previous embodiment, the pressure plate 64 may have a plain surface or include an edge, slot or aperture to facilitate cutting.

The plate 64 may be mounted for some slidable movement transversely of the length of webbing 68 to assist cutting.

The embodiment of Figs. 12 and 13 is similar to that described with reference to Figs. 9 and 10 except that the camming action is effected mainly by toggle links 71, 72. A handle 73 is mounted on pivots 74, 75 supported on spaced arms 76, 77. The toggle links 71, 72 are mounted on the handle by respective pivots 78, 79. The toggle links are also pivotally attached (as shown at 80) to each end of an elongate support 81 for a cutting blade 82. The arms 6. 77 extend from a support 83 which includes a slot 84 providing an edge adjacent the blade 82 to facilitate cutting. The handle 73 is raised in the direction of arrow 85 (Fig. 13) whereby the toggle links 71, 72 urge the blade 82 against a length of webbing 86 and into the slot 84.

The embodiment of Fig. 14 and 15 and illustrates a webbing cutter including a body 90 having a slot 91 therethrough to receive a length of webbing 92. A blade 93 is pivoted at one end 94 within the body 90 and has a push button 95 attached to its other end.

The push button 95 is depressed as shown by arrow 96 to urge the blade 93 towards the webbing 92. In this case the webbing is sheared. The floor of the support 90, which supports the webbing 92, may include an edge aperture or slot to facilitate cutting.

In the embodiment of Figs. 16 and 17, a body 98 includes a slot 99 therethrough for receiving a length of webbing 100. The internal surfaces of the slot 99 are bounded by a transverse slot 101. Slot 101 supports the upper and lower portions of a sliding blade 102 having a crescent shaped cutting edge.

The blade 102 is fixed at one end to a push member 103 which is urged in the direction of arrow 104 to sever the webbing. In an alternative embodiment, not shown, the blade 102 is spring driven and is released by a catch to traverse and thereby sever the webbing 100. The spring is loaded with the blade mounted in a storage position as shown, for example, in Fig. 17. Spring assistance may also be employed in the embodiments described with reference to Figs. 5 15.

In the embodiment of Figs 18-21. which is similar in principle to the latter embodiment, a two-part housing comprises an open-sided box 110 and a lid 111 (Figs. 19 and 20). Opposite longitudinal side walls 152, 153 of the box 110 contain aligned slots 112 and 113 to receive a length of webbing (not shown) which is supported by a convexly shaped inner surface 114 of the lid 111. The surface may alternatively be straight, i.e. so that it extends in the same plane beneath the level of the lower edges of the slots 112 and 113. The lid 111 contains a groove 115 to guide a sliding blade 116 which is supported in a sliding holder 117.

The blade has a straight cutting edge 118 inclined away from the direction of slidable movement as shown in Fig. 19.

A tray-shaped member 119 is inserted into the box 110, the tray having end walls 120, 121. A hole 122, in an end wall 123 of the box 110, is aligned with a hole 123 in the end wall 120 of the tray 119. This provides access for a loading tool or ram rod (not shown) to urge the slidable holder 117 back to a loaded position (shown in Figs. 18, 19) against the bias of a pair of springs 124, 125, The springs and the holder 117 are both supported on a pair of guide rods 126, 127 fixed between the end walls 120, 121 of tray 119. The holder has a pair of lugs 128, 129, and a central stem 130 which extends rearwardly of the direction of sliding movement and which define recesses 131, 132 to receive corresponding ends of the springs 124, 125. The other ends of the springs abut the end wall 121 of the tray. The holder may be a two part construction as indicated by the dividing line 133 and the opposite cross-hatching. The end of the blade 116 may have an aperture 134 to receive a central plug 136, which assists in securing together the two parts of the holder. The end of the stem 130 terminates in a latch portion 137 defined by recess 138,139 (Fig.

19). This latch portion is secured (with the holder in its loaded position) by the forked end 140 of a release member 141 (Fig. 21).

The release member 141 includes a pair of pins 142, 143 which are normally located in recesses 144 (only one being visible in Fig.

18). Recesses 144 contain springs 146 (only one being visible in Fig. 18) which bear against the forked end 140 of the release member 141. Member 141 is made of flexible material so that its forked end and the adjacent part 148 can be inserted in a recess 149 and the remaining major part 150 bent through 90C to be received in a retaining recess 151 in the outer surface of the longitudinal side wall 152 of the box 110 (Fig.

20). The part 150 then lies flush with the outer side surface of the assembly. Recess 151, over a section 153 (see Fig. 21), has the same shape as the part 150 (part of the lon gitudinal side wall 152 being shown by the broken line 154). The part 150. including a portion of increased width 155, is a force fit in recess 151 so as to prevent accidental displacement of the member 141 to a prerelease position. Member 141 terminates in a knob 156, which may be red in colour, and the part 150 is normally and additionally retained by a strip of adhesive material 157 (Fig. 18).

The holder is loaded as mentioned above, by forcing it back to the illustrated position (Fig. 18) with a tool or rod pushed through holes 122, 123. The forked end 140 of the release member is then inserted in recess 149 so that the pins enter the recesses 144, thereby compressing springs 146, and so that the forked end secures the latch portion 137. The part 150 is then folded back along the side wall 152 and forced into the recess 151 The adhesive strip 157 is then applied to the side wall 152. An apertured flange 158 is fixed to the lid 111 for fixing the assembly to the body of a vehicle.

In an emergency, the strip 157 is peeled back, the knob 156 is grasped and pulled away from the side wall 152 so that the forked end 140 can be pulled out of the recess 149, assisted by the springs 146. The holder is then released so that it is urged by springs 124, 125 towards the end wall 120 of the tray 119 to sever the webbing (not shown) which extends through the slots 112, 113.

An advantage of the cutter assembly shown in Figs. 18-21 is that the webbing slot may be made wider, whereby the webbing slides more freely through the latter slot and hence the assembly can be fixed to the body of the vehicle possibly out of reach of young children.

WHAT WE CLAIM IS: 1. A safety belt fitted with a webbing cuting device, the cutting device comprising at least one cutter mounted on a webbing support, which is adapted to support a length of webbing forming part of said belt, relative to the or each cutter, which is located in a storage position out of contact with said webbing, and means being provided to cause relative displacement between the cutter or cutters and the webbing to sever the webbing.

2. A safety belt according to claim 1 wherein the support includes at least one edge which provides a cutting support for the cutter.

3. A safety belt according to claim 2 wherein the edge is defined by an aperture or slot.

4. A safety belt according to any one of the preceding claims in which the or each cutter is displaceable across the webbing with respect to the webbing support.

5. A safety belt according to any one of claims 1-4 in which the webbing is displaceable with respect to a fixed cutter or cutters in said support.

6. A safety belt according to claim 4 wherein the or each cutter comprises a member which is preloaded in said storage position whereby it automatically traverses the support to sever the webbing when displaced from the storage position.

7. A safety belt according to claim 6 wherein the preloading is effected by the energy stored in a spring.

8. A safety belt according to claim 6 or 7 wherein said cutters are a pair of preloaded cutters which are displaceable so as to penetrate the webbing and subsequently move apart to sever the webbing.

9. A safety belt according to claim 4 wherein the or each cutter is displaceable in directions which are both perpendicular and transverse to the plane of the webbing.

10. A safety belt according to claim 4 wherein the or each cutter is displaceable in a direction which is transverse to the plane of the webbing.

11. A safety belt according to claim 4 wherein at least one of said cutters is displaceable relative to another one of said cutters so as to perform a shearing action.

12. A safety belt according to claim 4 wherein leverage is employed to facilitate displacement of the or each cutter to sever the webbing.

13. A safety belt according to any one of claims 4, or 6-12 wherein the support is of channel section having a flat floor extending between opposite sidewalls, the length of webbing being received on said floor and said floor including at least one edge which provides a cutting support for the cutter.

14. A safety belt according to claim 13 wherein the floor has an aperture or slot extending transversely of said length of webbing between said sidewalls, the cutter or cutters being displaceable in said aperture or slot to sever the webbing.

15. A safety belt according to claim 14 wherein the cutter or cutters are mounted on a bridge fitted to, or integral with the channel section support.

16. A safety belt according to any one of claims 4 or 6-12 wherein the support has an opening therethrough receiving the webbing, the support being fitted to the webbing in the manner of a sliding buckle, the support having slot which extends transversely of the opening and in which the or each cutter is displaceable to sever the webbing.

17. A safety belt according to any one of claims 14-16 wherein the or each cutter has an arcuate cutting edge.

18. A safety belt according to claim 4 wherein the support is of channel section with a flat floor extending between wall portions, said floor having a cutting slot extend

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

Claims

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

gitudinal side wall 152 being shown by the broken line 154). The part 150. including a portion of increased width 155, is a force fit in recess 151 so as to prevent accidental displacement of the member 141 to a prerelease position. Member 141 terminates in a knob 156, which may be red in colour, and the part 150 is normally and additionally retained by a strip of adhesive material 157 (Fig. 18).

The holder is loaded as mentioned above, by forcing it back to the illustrated position (Fig. 18) with a tool or rod pushed through holes 122, 123. The forked end 140 of the release member is then inserted in recess

149 so that the pins enter the recesses 144, thereby compressing springs 146, and so that the forked end secures the latch portion 137. The part 150 is then folded back along the side wall 152 and forced into the recess 151 The adhesive strip 157 is then applied to the side wall 152. An apertured flange

158 is fixed to the lid 111 for fixing the assembly to the body of a vehicle.

In an emergency, the strip 157 is peeled back, the knob 156 is grasped and pulled away from the side wall 152 so that the forked end 140 can be pulled out of the recess 149, assisted by the springs 146. The holder is then released so that it is urged by springs 124, 125 towards the end wall 120 of the tray 119 to sever the webbing (not shown) which extends through the slots 112, 113.

An advantage of the cutter assembly shown in Figs. 18-21 is that the webbing slot may be made wider, whereby the webbing slides more freely through the latter slot and hence the assembly can be fixed to the body of the vehicle possibly out of reach of young children.

WHAT WE CLAIM IS: 1. A safety belt fitted with a webbing cuting device, the cutting device comprising at least one cutter mounted on a webbing support, which is adapted to support a length of webbing forming part of said belt, relative to the or each cutter, which is located in a storage position out of contact with said webbing, and means being provided to cause relative displacement between the cutter or cutters and the webbing to sever the webbing.
2. A safety belt according to claim 1 wherein the support includes at least one edge which provides a cutting support for the cutter.
3. A safety belt according to claim 2 wherein the edge is defined by an aperture or slot.
4. A safety belt according to any one of the preceding claims in which the or each cutter is displaceable across the webbing with respect to the webbing support.
5. A safety belt according to any one of claims 1-4 in which the webbing is displaceable with respect to a fixed cutter or cutters in said support.
6. A safety belt according to claim 4 wherein the or each cutter comprises a member which is preloaded in said storage position whereby it automatically traverses the support to sever the webbing when displaced from the storage position.
7. A safety belt according to claim 6 wherein the preloading is effected by the energy stored in a spring.
8. A safety belt according to claim 6 or 7 wherein said cutters are a pair of preloaded cutters which are displaceable so as to penetrate the webbing and subsequently move apart to sever the webbing.
9. A safety belt according to claim 4 wherein the or each cutter is displaceable in directions which are both perpendicular and transverse to the plane of the webbing.
10. A safety belt according to claim 4 wherein the or each cutter is displaceable in a direction which is transverse to the plane of the webbing.
11. A safety belt according to claim 4 wherein at least one of said cutters is displaceable relative to another one of said cutters so as to perform a shearing action.
12. A safety belt according to claim 4 wherein leverage is employed to facilitate displacement of the or each cutter to sever the webbing.
13. A safety belt according to any one of claims 4, or 6-12 wherein the support is of channel section having a flat floor extending between opposite sidewalls, the length of webbing being received on said floor and said floor including at least one edge which provides a cutting support for the cutter.
14. A safety belt according to claim 13 wherein the floor has an aperture or slot extending transversely of said length of webbing between said sidewalls, the cutter or cutters being displaceable in said aperture or slot to sever the webbing.
15. A safety belt according to claim 14 wherein the cutter or cutters are mounted on a bridge fitted to, or integral with the channel section support.
16. A safety belt according to any one of claims 4 or 6-12 wherein the support has an opening therethrough receiving the webbing, the support being fitted to the webbing in the manner of a sliding buckle, the support having slot which extends transversely of the opening and in which the or each cutter is displaceable to sever the webbing.
17. A safety belt according to any one of claims 14-16 wherein the or each cutter has an arcuate cutting edge.
18. A safety belt according to claim 4 wherein the support is of channel section with a flat floor extending between wall portions, said floor having a cutting slot extend

ing between said wall portions; mounting means being fixed to said support, said mounting means having a storage slot; a coil spring being supported by said mounting means, the coil spring having sharpened end portions which are normally located in said storage slot adjacent but spaced from said cutting slot; the means for displacing said cutter or cutters being such as to displace the end portions of the spring from the storage slot so that they penetrate the webbing, enter the cutting slot and subsequently spring apart to sever the webbing.
19. A safety belt according to claim 4 wherein the cutter is in the form of a blade located in a storage slot in said support, the blade having a chamfered edge, and said means for causing relative dispacement comprising a member mounted for transverse movement along the storage slot so as to engage the chamfered edge of the blade and cause it to move obliquely towards the webbing.
20. A safety belt according to claim 4 wherein the cutter is in the form of a circular blade located in a storage slot in said support and said means for causing relative displacement is a member for urging the cutting blade across the storage slot to sever the webbing.
21. A safety belt according to claim 4 wherein the cutter is in the form of a blade mounted for movement towards the webbing and the means for causing relative displacement comprises a lever witha cam portion for engaging and urging said blade towards the webbing.
22. A safety belt according to claim 5 wherein the support defines a recess bounded by shoulder portions on which the webbing is supported, the recess containing a blade on one side of the webbing and the means for causing relative displacement comprising a member on the other side of the webbing and which can be urged towards said blade.
23. A safety belt according to claim 4 wherein the cutter is in the form of a blade mounted for movement towards the webbing and the means for causing relative displacement comprises a lever connected by a toggle link or links to the blade for urging it towards the webbing.
24. A safety belt according to claim 4 wherein cutters are provided in the form of a fixed blade and a moveable blade pivotally mounted thereon, the webbing being received between said blades; the means for causing relative displacement being provided to cause the moveable blade to move towards the fixed blade.
25. A safety blade according to claim 4 wherein the cutter is in the form of a blade located in a slot in said support, the blade normally being located in a storage position at one end of said slot and the means for causing relative displacement being provided for urging said blade along the slot to sever the webbing.
26. A safety belt according to claim 25 wherein the support is in the form of a housing having an opening therethrough to receive the length of webbing, said slot being transverse to said opening, the blade being mounted in a holder slidably mounted in the housing, the housing containing a spring or springs to urge the holder, and hence the blade, along the slot to sever the webbing and the holder being secured in said storage position by a release member supported by the housing.
27. A safety belt according to claim 26 wherein the release member is secured in a recess in the housing and has a forked end to latch a stem portion of the holder in said storage position; the release member being withdrawn from the housing to release the holder.
28. A safety belt fitted with a webbing cutting device substantially as herein described with reference to Figs. 3 and 4 of the accompanying drawings.
29. A safety belt fitted with a webbing cutting device substantially as herein described with reference to Figs. 5 and 6 of the accompanying drawings.
30. A safety belt fitted with a webbing cutting device substantially as herein described with reference to Figs. 7 and 8 of the accompanying drawings.
31. A safety belt fitted with a webbing cutting device substantially as herein described with reference to Figs. 9 and 10 of the accompanying drawings.
32. A safety belt fitted with a webbing cutting device substantially as herein described with reference to Fig. 11 of the accompanying drawings.
33. A safety belt fitted with a webbing cutting device substantially as herein described with reference to Figs. 12 and 13.
34. A safety belt fitted with a webbing cutting device substantially as herein described with reference to Figs. 14 and 15.
35. A safety belt fitted with a webbing cutting device substantially as herein described with reference to Figs. 16 and 17.