Buckles – buttons – clasps – etc. – Separable-fastener or required component thereof – Including member having distinct formations and mating...
Reexamination Certificate
1999-02-04
2001-01-09
Brittain, James R. (Department: 3626)
Buckles, buttons, clasps, etc.
Separable-fastener or required component thereof
Including member having distinct formations and mating...
C024S633000
Reexamination Certificate
active
06170134
ABSTRACT:
DESCRIPTION
The present invention relates to a seat belt buckle and in particular to a buckle which is resistant to spurious disengagement under high g-forces such as are experienced when a pretensioner which is fitted to the anchorage of a buckle fires under crash conditions.
A seat belt buckle is known from EP 0 384 703 in which a locking element pivots into and out of a position in which a locking projection of the locking element engages an aperture in a tongue to be fastened into the buckle. The locking element is pivoted out of engagement by a translational motion of a buckle release button. In the locking position it is held in place by an overlocking pin guided in slots in the buckle frame and by a spring loaded rocking member which is pivotally mounted on the locking element. The rocking member is inertially balanced to block the overlocking pin in the buckle locked portion under certain inertial conditions.
However this known buckle is not immune to the very high g-forces caused by modern pretensioners acting on a buckle anchorage in a crash.
Improvements to the buckle have thus been suggested to the buckle of EP 0 384 703 in which a further member is used to constrain the overlocking member in its locking position.
Further improvements are disclosed in EP 0 559 403 in which an overlocking plate is slidably held in slots in the release button. Under the high g-forces generated by firing of a pretensioner and specifically by the deceleration forces at the end of the pretensioning stroke, the inertial of the overlocking plate causes it to slide into a position in which it blocks release of the locking element. Once the pretensioning operation is complete the high g-forces subside, and the release button returns under spring pressure to its normal position, releasing the overlocking plate from the locking element and thus buckle release is again enabled on depression of the release button.
The present invention aims to further improve the above mentioned buckle making it faster and more reliable.
According to the present invention there is provided a buckle for a vehicle safety restraint mechanism, the buckle comprising:
a housing having a rectilinear channel for receiving a fastening member;
a locking member mounted within the housing and moveable between a first position in which it engages the fastening member and a second position in which the fastening member is released;
a release button operatively connected to the locking member for effecting movement thereof between the first and second positions;
a blocking member such as a sliding plate for engaging the latching element under predetermined conditions to prevent movement of the locking member towards the release position; and
an inertial mass pivotally mounted to, and contained within side walls of, the release button, the mass being arranged to act on the blocking member under said predetermined conditions to move the blocking member to a position in which the locking member is retained in the first position.
The predetermined conditions are preferably those experienced when an acceleration force is present of greater than a predetermined value, for example the acceleration force experienced by the buckle at the onset of a pretensioning operation.
Thus it will be seen that the improved buckle of the invention causes the pretensioner-proof blocking member to move into its blocking position during the acceleration phase of the pretensioning operation, thus securing the buckle against spurious release before the deceleration phase. This is earlier than in the known systems described above in which the blocking action only becomes operative during the deceleration phase and in which there is the danger of the button inertia opening the buckle before the blocking action has become fully operative.
According to a preferred embodiment the buckle further comprises resilient means such as a spring for resetting the mass and the overlocking member when the predetermined conditions are no longer present, for example when the forces associated with the pretensioning operation are dissipated.
REFERENCES:
patent: 5280669 (1994-01-01), Nanbu et al.
patent: 0679348 (1995-02-01), None
patent: 0507266 (1992-07-01), None
patent: 0680705 (1995-08-01), None
patent: 680705 (1995-11-01), None
patent: 2223265 (1990-04-01), None
Burke David
Downie Andrew John
Breed Automotive Technology Inc.
Brittain James R.
Seitzman Markell
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