Buckles – buttons – clasps – etc. – Separable-fastener or required component thereof – Including member having distinct formations and mating...
Patent
1997-04-14
1998-07-28
Sakran, Victor N.
Buckles, buttons, clasps, etc.
Separable-fastener or required component thereof
Including member having distinct formations and mating...
24643, 24644, A44B 1100
Patent
active
057847665
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The present invention relates to a buckle mechanism, particularly to a buckle mechanism for use in vehicle safety restraint systems.
Government safety regulations and strict standards laid down by vehicle manufacturers require such buckles to engage easily, securely, reliably and without error, to restrain a vehicle occupant throughout a variety of crash situations and to be easily and positively releasable when required.
There are a variety of known buckle mechanisms. For example in which a pivoting locking member engages a slot in a cooperating tongue attached to a safety restraint belt, and is disengaged by means of a button on the buckle housing.
Springs are provided to bias parts of the buckle in appropriate directions, e.g. to avoid spurious release and to retain the tongue securely.
Such buckle has a good latching and release mechanism but requires many parts in its construction making it expensive to manufacture and introducing more potential for unreliability.
A recent requirement of some vehicle manufacturers is that a buckle be shock proof. This is particularly important when pretensioners are used in cars to take up excess slack in a restraining belt when a crash situation is detected. The pretensioner may be arranged to take up the slack either at the retractor end of the belt or at the buckle end. When it is fitted to the buckle end, the buckle mechanism is typically pulled back to take up the slack at a force of up to 6000 g and such a force has been known to release the buckle mechanism due to the inertia of the buckle button.
To avoid this situation, it is known to counterbalance the mass of the button. However, this has not been found to produce the reliable results required in safety restraint systems.
According to a first aspect of the present invention, there is provided a buckle mechanism comprising a movable button member, and locking means movable transversely to the plans of movement of the button to engage or disengage a locking surface of a cooperating tongue wherein mutually cooperating abutments are provided respectively on the button member and on the locking means to lock the button against forces tending to move the locking means to a position of disengagement.
The locking means is preferably resiliently biased, for example by means of a leaf spring, into locking engagement with the tongue. It may comprise a locking member guided by a rocking support member on which one of the abutments is provided.
Preferably an overlocking member is provided resiliently biased in the tongue withdrawal direction but slidably mounted to overcome the resilient bias in the event of crash inertia forces and having at least one overlocking surface to block movement of the locking member out of engagement with the tongue in a crash situation.
It will be seen that the provision of the cooperating abutments serves to avoid disengagement of the buckle mechanism of the invention during pretensioning while the overlocking member prevents disengagement at the end of the pretensioning operation, i.e. prevents the negative g forces from having an effect.
Additionally, the buckle of the present invention avoids spurious release in the event of shock from side impacts since the cooperating abutments even then hold the button in place, and the overlocking surface further prevents sideways movement of the locking member in the event of a shock.
Previously known buckle mechanisms, including compensating mass systems cannot prevent spurious release in such a variety of directions.
Preferably the button member has a ramp surface to effect disengagement of the buckle and it comprises three parts of different gradients. The part closest to the locking member has a gradient of between 40.degree. and 60.degree. relative to the plane of the tongue, more preferably between 45.degree. and 55.degree. and most preferably of about 50.degree.. It is found that this angle best resists spurious release of the buckle yet provides for an easy enough unbuckling operation for example for women and children to accom
REFERENCES:
patent: 4393557 (1983-07-01), Schmidt
patent: 5014401 (1991-05-01), Kitazawa
Burke David
Downie Andrew John
Allied-Signal Inc.
Sakran Victor N.
Seitzman Markell
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