LOCK FOR SAFETY BELT, PARTICULARLY FOR CHILDREN

Abstract: Buckle for a safety belt, particularly a children's belt, comprising a buckle housing (10) and a lock tongue (13) constructet to be connected each to one strap part. The lock tongue is insertable into a guide (15) in the buckle housing which has a latch member (19) spring biased to lockingly engage the inserted lock tongue, and an operating member (20) to be operated manually for switching the latch member from an engaged position to a disengaged position against the spring bias, said two members consisting of one and the other, respectively, limb of a U-shaped element (17) which is pivotally mounted in the buckle housing (10) to swing about a transverse axis (21) with the limbs extending along the guide (15) towards the insertion opening (12) for the lock tongue (13) which at the insertion into the buckle housing can be pushed in between the limbs. The spring bias consists of a pressure spring (26) mounted between the limbs one end of said spring abutting the web of the U-shaped element, the lock tongue at the insertion between the limbs being engageable with the other end of the spring to tension the pressure spring which is provided also as ejector for the lock tongue.

Description: LOCK FOR SAFETY BELT, PARTICULARLY FOR CHILDREN The invention relates to a buckle for a safety belt, particularly a child's belt of the type used in combination with a child's chair which is located on a seat and is anchored to the car. The buckle according to the invention comprises a buckle housing and a lock tongue constructed to be connected each to one strap part, the lock tongue being insertable into a guide in the buckle housing which has a latch member spring biased to lockingly engage the inserted lock tongue, and an operating member to be operated manually for switching the latch member from an engaged position to a disengaged position against the spring bias. It is the intention to provide by the invention a buckle of this kind which combines an extremely uncomplicated construction with high safety and reliability and wherein the uncomplicated construction is achieved by the buckle consisting of very few elements which are of a simple construction and are mounted together in a simple manner. As a consequence thereof the buckle can be made small and light, which is desired as far as buckles for a child's belt is concerned. For said purpose the buckle according to the invention has obtained the characterizing features of claim 1. An embodiment of the buckle according to the invention will be described below reference being made to the accompanying drawings in which FIG 1 is an exploded perspective view of a child's buckle for a belt having a crotch strap and two shoulder straps, FIG 2 is a vertical cross sectional view of the buckle in FIG 1, and FIG 3 is a vertical cross sectional view similar to FIG 2 of a buckle of a slightly modified embodiment. The buckle comprises a buckle housing 10 which can be injection moulded of a suitable plastic material and has at one end thereof a cross bar 11 to be connected at said cross bar to a crotch strap forming part of a child's belt, said part extending downwards between the child's legs and is fixedly anchored below. The buckle housing forms at the other end thereof a slot opening 12 for insertion of two lock tongues 13 and 14 which shall be connected each to one shoulder strap. Inside the buckle housing there is provided along each of the opposite sides of the housing a linear guide groove 15 for guiding the lock tongues when they are inserted into the buckle housing through the opening 12. In one of the flat sides of the buckle housing an opening 16 is provided. A U-shaped element 17 stiffened by means of a flange 18 extending between the two limbs 19 and 20 of the element and along said limbs, is inserted into the buckle housing through the opening 16 and is pivotally mounted in the buckle housing by means of a pin 21 which is inserted transversely of the buckle housing into apertures 22 therein and extends through an aperture 22A in the element 17, said latter aperture being located in the transition between the web of the element and the limb 19. The limbs 19 and 20 extend along the guides 15 towards the opening 12. The U-shaped element 17 forms a latch member as well as an operating member of the buckle. The limb 19 forms the latch member and for this purpose has a slightly undercut latch dog 23 forming a bevelled surface 24, and the limb 20 forms the operating member and is available for manual operation through the opening 16. This limb has a dimple forming a pressure point 20A on the outside thereof. On one side of the flange 18 the element 17 has a hook 25 extending along said flange, for fixedly positioning one end of a helical spring 26 which extends along the flange 18 at one side thereof and functions as a spring for biasing the latch dog 19 to the engaged position as well as an ejection spring. The lock tongue 13 has a lug 27 with a slot 28 therein for connection of the related shoulder strap which shall extend upwards over the shoulder of the person to be belted and shall be fixedly anchored behind the seat or chair or in the back thereof. Moreover, the lock tongue forms a hook 29 which is undercut in a corresponding manner as the latch dog 23 and is constructed to engage with said latch dog. In a corresponding manner the lock tongue 14 has a lug 30 with a slot 31 for the connection of the related shoulder strap, and it forms also a hook 32 which is also undercut. When the lock tongue 14 is disposed on top of the lock tongue 13 the hook 32 shall engage an edge surface 33 on the lock tongue 13, which is formed in a corresponding way, as shown in FIG 2. The two lugs are angled in opposite directions as can be seen in FIG 1 in order not to interfere with each other when the two lock tongues are put together with one lock tongue disposed on top of the other. Both lock tongues have a slot 34 and 35 respectively, to receive therein the flange 18 of the element 17 when they are pushed into the buckle housing. When the two lock tongues put together in the manner described are pushed into the buckle housing 10 through the opening 12 they will be guided linearly by the guides 15 in the lock housing between the limbs 19 and 20. The end edge of the lock tongue 14 will abut the free end of the spring 26 such that the spring will be compressed and put under tension when the lock tongues are being inserted, which means that the element 17 will be biased to swing counter¬ clockwise as seen in FIG 2 about the pivot axis defined by the pin 21. The limb 19 thus will be swung towards the lock tongues under the spring bias but will be pushed aside by cam action of the lock tongue 13 against the spring bias by said lock tongue sliding against the bevelled surface 24. When the lock tongues are completely inserted, which is indicated by shoulders 36 formed by the lugs engaging the end wall of the buckle housing, the element 17 will be swung counter-clockwise as seen in FIG 2 under the influence of the tensioned spring 26, the latch dog 23 at the same time engaging the hook 29 of the lock tongue 13. Now, the lock tongues are lockingly engaged with the buckle housing. The tension load to which the lock tongues and the buckle housing may be exposed when the belt is being used, will be taken up by the buckle housing not only via the pin 21 but also at the free end of the limb 19, said end engaging at 37 the end wall of the buckle housing wherein the opening 12 is provided. It should also be noted that the position of the element 17 is defined by a projection 38 on said element engaging the other end wall of the buckle housing, the limb 20 of the element 17 being substantially flush with the flat side of the buckle housing in the opening 16. In order to disengage the lock tongues from the buckle housing when the belt is to be taken off pressure is applied to the element 17 at the pressure point 20A on the limb/operating member 20 in order that the element 17 will be swung clockwise as seen in FIG 2 against the bias of the tensioned spring 26 so that the latch dog will disengage the hook 29 on the lock tongue 13. When this happens the spring 26 functioning as an ejection spring can push the lock tongues out of the buckle housing. Thus, it will be seen that the buckle according to the invention has one moveable element only, namely the element 17 which forms the latch member as well as the operating member, and one spring only, namely the spring 26 which is a spring biasing the latch member and an ejection spring. Totally the buckle comprises (excluding the lock tongues) four elements only: the buckle housing 10, the element 17, the pin 21, and the spring 26, an extremely low number of elements of a lock of the type referred to herein. It has been possible to obtain this simplification of the lock without renouncing the safety and reliability. If it is desired to increase the pressure required in order to disengage the buckle when pressure is exerted on the element 17 at the pressure point 20A, a spring blade 39 can be provided according to FIG 3 between the buckle housing 10 and the limb 19 of the U-shaped element 17, the ends of the spring blade being displaceably received by a shallow groove 40 in the buckle housing and the spring blade being bow-shaped to engage between the ends thereof the limb 19. The spring blade can be replaced by a helical spring provided as a pressure spring between the buckle housing and the limb 19. The buckle described is a children's buckle, i.e. a buckle for such belts as are used in combination with a child's chair, but it is realized that the lock can be used also with other car belts, the buckle housing and one lock tongue being connected with a hip strap, and the other lock tongue being connected with a shoulder strap when the lock is used in combination with a common car belt of the three point type. It is, of course, not necessary that two lock tongues can be inserted into the buckle housing. The buckle can be constructed also for one lock tongue only as when the shoulder strap of a three point belt passes through a slot in the single lock tongue and is integral with a hip strap part, or in case of a hip belt wherein the lock tongue and the buckle housing are connected each with one hip strap part.

Claims: CLAIMS 1. Buckle for a safety belt, particularly a children's belt, comprising a buckle housing (10) and a lock tongue (13) constructed to be connected each to one strap part, the lock tongue being insertable into a guide (15) in the buckle housing which has a latch member (19) spring biased to lockingly engage the inserted lock tongue, and an operating member (20) to be operated manually for switching the latch member from an engaged position to a disengaged position against the spring bias, c h a r a c t e r i z e d in that the latch member (19) and the operating member (20) consist of one and the other, respectively, limb of a U- shaped element (17) which is pivotally mounted in the buckle housing (10) to swing about a transverse axis (21) with the limbs extending along the guide (15) towards the insertion opening (12) for the lock tongue (13) which at the insertion into the buckle housing can be pushed in between the limbs, and that the spring bias consists of a pressure spring (26) mounted between the limbs one end of said spring abutting the web of the U-shaped element, the lock tongue at the insertion between the limbs being engageable with the other end of the spring to tension the pressure spring which is provided also as ejector for the lock tongue. 2. Buckle as in claim 1, c h a r a c t e r i z e d in that a stiffening flange (18) is provided between the limbs (19,20) said flange extending along the limbs, the lock tongue (13) being slotted to receive in the slot (34) the stiffening flange at insertion of the lock tongue into the buckle housing. 3. Buckle as in claim 1 or 2, c h a r a c t e r¬ i z e d in that the guide (15) for the lock tongue (13) comprises guide grooves in the side walls of the lock housing (10) . 4. Lock as in any of claims 1 - 3, c h a r a c¬ t e r i z e d in that the transverse axis (21) for the pivotal mounting of the U-shaped element (17) in the buckle housing (10) is located in the region of the corner between the limb (19) forming the latch member, and the web of the U-shaped element. 5. Buckle as in any of claims 1 - 4, c h a r a c¬ t e r i z e d in that the limb (19) forming the latch member when engaged abuts at the free end thereof an end wall of the buckle housing (10). 6. Lock as in claim 5, c h a r a c t e r i z e d in that the U-shaped element (17) when engaged abuts at the web thereof the opposite end wall of the buckle housing. 7. Buckle as in any of claims l - 6, c h a r a c- t e r i z e d in that the limb (20) forming the operating member is available through an opening (16) in the flat side of the buckle housing (10). 8. Buckle as in any of claims 1 - 7, c h a r a c¬ t e r i z e d in that a second lock tongue (14) can be disposed on said lock tongue (13) engaging the latch member (19), in a plane parallel therewith and is constructed to positively engage with the first mentioned lock tongue at a hook-shaped flange (32) at the free end thereof. 9. Buckle as in any of claims l - 7, c h a r a c- t e r i z e d in that a pressure spring (39) is provided between the buckle housing (10) and the limb (19) of the U- shaped element (17) forming the latch member. 10. Buckle as in claim 9, c h a r a c t e r i z e d in that the pressure spring comprises a curved spring blade (39) the ends of which are displaceably received in a shallow groove (40) in the buckle housing (10) and engages said one limb (19) between the ends thereof.

Inventors: OLSON ULF, OLSON, ULF
Applicants: HOLMBERGS FAB AB BRDR, BROEDERNA HOLMBERGS FABRIKS AB
Application year: 1992
Main classification: A44B11
IPC codes: A44B11