Winding – tensioning – or guiding – Reeling device – With spring motor
Patent
1996-12-10
1998-05-12
Darling, John P.
Winding, tensioning, or guiding
Reeling device
With spring motor
B60R 2246
Patent
active
057495360
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The invention relates to a coupling for torque transfer from a propellant-operated rotary drive to a belt shaft of a seat belt retractor for tensioning a seat belt, including at least one coupling element maintained in the uncoupled condition in the resting status and which, for torque transfer in coupling engagement, is engaged with an engaging part connected to the belt shaft.
The object of the invention is to define such a coupling which ensures a compact configuration.
This object is achieved in accordance with the present invention in that the coupling element is swivably mounted on a component rotatively driven by the propellant and is maintained in the uncoupled condition by a retaining means and in that the coupling element is swivable into coupling engagement by a force generated by the propellant.
The propellant involved may be a drive medium, held in a stored energy operating mechanisms for example a compressed gas or a pyrotechnic propellant by which a compressed gas is generated on ignition. The rotary drive may be configued as a rotational drive as is described in EP 0 648 652 A1 or EP 0 673 811 A1. It may, however, also involve a sheave driven by a linear piston drive via an actuating cable as described for example in EP 0 529 265 A1 or GB 2 180 734 A1.
The coupling element may be swivelled into coupling engagement against a retaining force exerted by the retaining means, particularly a spring force. The effect of the force generated by the propellant is preferably terminated after the engaging action. The coupling element may be retained in the engaging position during torque transfer by a self-retaining force acting thereby between the engaging part and the coupling element. Preferably, the coupling element may be returned, after tensioning of the seat belt, into the uncoupled condition. As a result of which, the belt shaft on rotation, particularly in the webbing withdrawal direction, is released. Returning it into the uncoupled condition may be affected by spring force, particularly by the spring force generated by the retaining means.
For engaging the coupling in the engaging position especially the initial phase of the pressure build-up generated by the propellant is made use of. For example, the force furnished by the propellant may be converted into a movement for engaging the coupling element in the engaging movement indirectly by a relative movement being produced between two components driven by the propellant which affects a force acting on the coupling element in the direction of engagement. Furthermore, it is possible that the pressure generated by the propellant, particularly in the initial phase of pressure build-up, is caused to affect the coupling element directly so that it is pneumatically engaged from the resting position into the engaging position.
Preferably the retaining means comprises a carrier which takes the form of a spring, particularly a leaf spring. The carrier for the swivably mounted coupling element retains the coupling element in the normal condition in its resting position and returns the coupling element on completion of tensioning of the seat belt into its resting position.
In the case of the force generated kinematically by the relative movement of two components driven by the propellant and acting on the coupling element, it is preferably provided for that the two components, by which the coupling element is supported, feature differing angular velocities about an axis which preferably coincides with the belt shaft axis. Due to the differing angular velocities the retaining means or a part thereof, particularly the carrier, is moved so that a force is continuously exerted on the coupling element during the engaging action. The fastening points at which the coupling element is secured via the retaining means to the two components may be arranged at a specific angular spacing from each other about the belt shaft axis, this angular spacing being preferably approx. 180.degree. or slightly more.
A suitable carrier is configured band-shaped and
REFERENCES:
patent: 4423846 (1984-01-01), Fohl
patent: 4455000 (1984-06-01), Nilsson
patent: 5114090 (1992-05-01), Lindblad
patent: 5383623 (1995-01-01), Hiruta et al.
patent: 5451008 (1995-09-01), Hamaue
patent: 5681004 (1997-10-01), Specht
Krauss Walter
Specht Martin
Darling John P.
TRW Occupant Restraint Systems GmbH
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