LOCK FOR VEHICLE SAFETEY BELTS

Abstract: Lock for vehicle safety belts of the three-point type with a strap loop (27) which forms a hip strap part and a chest strap part. The lock comprises a guide tongue (25) displaceably arranged on the strap loop and having a slot (26) for the passage of the strap (27) around the outer side of a channelled strap guide (28) arranged on the guide tongue, which is located on the inner side of the strap loop. Furthermore, the lock comprises a lock housing (10) which is arranged to receive in a slot guide (29) the guide tongue and for retaining engagement with the strap loop has at least one lock member (11) to be located in the channelled strap guide when the guide tongue is inserted into the lock housing.

Description: LOCK FOR VEHICLE SAFETY BELTS The invention relates to a lock for vehicle safety belts of the three-point type with a strap loop, comprising a lock housing with at least one lock member for retaining engagement with the strap loop- There can be distinguished between two main types of such locks. One type, the most common one, comprises * • a lock tongue which is arranged on the strap running through a slot in the lock tongue, and is inserted into the lock housing through a slot therein to engage one or more lock members tn the housing. The advantage of locks of this type is that the lock is easy to use, because everyone understands at once that the lock tongue should be inserted into the lock housing when it is desired to take on the vehicle safety belt. Moreover, a marked click in the lock indicates that the lock member or members have engaged the lock tongue, which ensures that the vehicle safety belt has been taken on in a correct way to provide the intended security during driving. Since the lock tongue is a load-receiving part of the vehicle safety belt, it must be made of steel sheet and therefore it will be relatively heavy. As a consequence thereof the lock tongue puts a load which is not unessential, on the strap roller for retracting the strap loop, usually provided, when the vehicle safety belt is taken off. It follows that the retraction spring of the strap roller must be relati ye.ly heavy and that the cffest part of the strap loop when in use accordingly will provide a relatively heavy pressure over the chest of the user of the vehicle safety belt, which is felt uncomfortable by many persons. This is avoided in locks of the other type which haye no lock tongue at all . The strap loop is laid instead under a bar of the lock which is termed leaf lock or insert lock. This bar is pivoted and can be locked and thus retains the vehicle safety belt in the operative position by engaging directly the strap loop. The drawback of leaf locks is that many persons do not understand how to do 1n order to lock the vehicle safety belt in the operative position thereof and moreover feel some uncertainty in ascertaining if the vehicle safety belt is taken on correctly and in fact provides the security which is relied on. For the person who is used to the leaf lock it is, however, a ve ry excellent lock which is easy to use and provides exactly the same security as any other helt lock. The purpose of the invention is to increase the comfort of a vehicle safety belt of the type referred to ahove and to provide a lock which combines the best features of the present locks for vehicle safety belts of the two main types mentioned above by elimination of the heavy lock tongue, the lock at the same time being of such dasign that there may be no doubt how to use the lock, and that the lock provides excellent security. This purpose is achieved by the lock of the type referred to above having obtained the characteristics according to claim 1. fn such a lock the guide tongue with the strap guide can be constructed as a light element of plastic material, because the guide tongue has no load-receiving function at all. I ~ n order to explain more clearly the invention a - principle embodiment will be described in more detail below reference Being made to the accompanying drawings in which FIG. 1 is a side view of the lock mechanism in engaged position, FIG. 2 is a cros-s-sectional view along line II- II in FIG. 1 , -4 FIG. 3 is a fragmentary cross-sectional view along line III - III in FIG. 1 , FIG. 4 is a fragmentary cross-sectional view along 5 line IV - IV in FIG. 1 , and ( FIG. 5 is a fragmentary side view of the lock mechanism in disengaged position. Referring to the drawings, the lock according to the invention comprises a lock housing 10 which is shown 10 fragmentarily only in the drawings, with a lock mechanism arranged therein including two lock members formed as two hook-shaped arms 11 which are pivotally mounted at 12 inside the lock housing, preferably in a metal frame arranged in the lock housing, which is not shown here 15 in order not to mak.e the drawing too complicated. A helical tension spring 13 is engaged between the arms and tends to move the arms apart to the disengaged position shown in FIG. 5. However, a rejector 15 biased by means of a helical compression spring 14 is dis- 20 placeably guided in the lock housing and can be depressed in order to co-operate with cams 16 formed by the arms 11 so as to bring the arms to the engaged position of FIG. 1 against the bias of the spring 13. The rejector 15 forms two shoulders 17 for engage- 25 ment with two rails 18 which are arranged in the lock housing and can be moved apart against the bias of springs 19. This can be done by -means of a wedge member 20 at one end of a bar 21 which is guided for axial displ cement in the lock housing and at the other end 3Q thereof is provided with a push button 22 for axial dis¬ placement of the bar and thus the wedge member against the bias of a helical compression spring 24 in the lock housing. The wedge member 20 then is moved downwards between the rails 18 such that these rails are forced 35 apa.rt against the spring bias and as a consequence thereof are disengaged from the shoulders 17. The lock also comprises a guide tongue 25 form¬ ing a slot 26 for the passage of the belt strap 27 which in a known manner forms a chest strap part and 5 a hip strap part which join each other at the guide ■ tongue. The guide tongue is integral with a channelled strap guide 28 which should be located at the inner side of the strap loop formed by the strap. The strap guide is substantially V-shaped with a gently curved ■ JO apex in order that the strap shall slide easily against the outer side of the strap guide without being exposed to heavy wear. The guide tongue and the strap guide can be formed as a light injection moulded element of plastic material, because the guide tongue has no load- 15 -receiving function in the lock of the invention. The lock housing is provided with a guide 29 formed as a slot to receive therein the guide tongue 25 with the strap guide 28 located outside the lock housing as shown in FIG, 2. 2Q When the vehicle safety belt is being used, the strap loop 27 is pulled out by gripping the lock tongue 25, the strap sliding through the slot 26 around the strap guide 28. The guide tongue is inserted into the slot guide 29. under depression of the rejector 15 25 against the bias of the compression spring 16, the arms 11 being swung towards each other against the bias of the tension spring 13 by co-operation of the rejector with the cams 16 of the arms. Then, these arms are swung towards' each other and into the channelled strap guide 30 28 arranged on the guide tongue, to the position accord¬ ing to FIG. 1 and thereafter will be maintained in this position by engagement of the rejector with the rails 18 at the shoulders 17 under the bias of the springs 19. When the strap is to be released in order to take 35 off the vehicle safety belt, the push button 22 is depressed manually, the rails 18 being moved apart and thus being disengaged from the rejector 15 which will be pressed upwards under the bias of the spring 16 to allow movement of the arms 10 to the disengaged posi¬ tion according to FIG. 5 under the bias of the tension spring 13 which at the same time pushes the guide tongue out of the lock housing. The embodiment of the invention, which has been shown, serves the purpose of illustrating the principles of the invention only. As far as the practical design of the lock of the invention is con¬ cerned the constructive details may be modified within the scope of the inventive concept defined in the claims

Claims: CLAIMS 1. Lock for vehicle safety belts of the three- -point type with a strap loop (27), comprising a lock housing (10) with at least one lock member for retain¬ ing engagement with the strap loop, c h a r a c t e r ¬ z e d in that there is displaceably arranged on the strap loop (27) a guide tongue (25) having a slot (26) for the passage of the strap (27) around the outer side of a channelled strap guide (28) arranged on the guide 10. tongue and located on the inner side of the strap loop, and that the lock housing (10) is arranged to receive in a slot guide (29) the guide tongue with the lock memher (11) located in the channelled strap guide. 2, Lock according to claim 1 , c h a r a c t e r ¬ 15 i z e d in that two hook-shaped arms (11) which can be swung towards and away from each other, are arranged in the lock housing as lock members for retaining engagement with the strap loop (27). 20

Inventors: SYLVEN HANS, SYLVEN, HANS
Applicants: STIL IND AB, AB STIL-INDUSTRI
Application year: 1983
Main classification: A44B11
IPC codes: A44B11