Attenuated seatbelt stopper
First Claim
1. A force limiting device for use with a safety belt retractor, the safety belt retractor including a spool, a safety belt webbing attached to and wound around the spool, the spool being rotatable to wind in the webbing and to payout the webbing under the influence of forwardly directed movement of a vehicle occupant, the force limiting device comprising:
- a fixed member;
a shaft connected to the fixed member, at least a portion of the shaft is threaded; and
a coupling received on the shaft and having an internal thread for threadedly engaging the threaded portion of the shaft, the coupling being configured to move along a longitudinal extent of the shaft, the coupling being operatively connected to the spool and moving towards the fixed member during payout of the webbing, engagement of the coupling with the fixed member preventing further payout of the webbing,wherein the threaded portion of the shaft includes a first threaded section having a first thread pitch and a second threaded section having a second thread pitch, each of the first thread pitch and the second thread pitch differs from a thread pitch of the coupling to limit movement of the coupling along the longitudinal extent of the shaft during payout of the webbing by increasing the force required to turn the coupling on the threaded portion of the shaft, the first threaded section providing a generally constant belt force on the vehicle occupant, the second threaded section providing an increasing belt force on the vehicle occupant.
1 Assignment
0 Petitions
Accused Products
Abstract
A force limiting device for use with a safety belt retractor is provided. The safety belt retractor includes a spool and a safety belt webbing attached to and wound around the spool for payout of the webbing under the influence of forwardly directed movement of a vehicle occupant. The force limiting device comprises a fixed member, a shaft connected to the fixed member and a coupling received on the shaft and operatively connected to the spool. The coupling is configured to move along the longitudinal extent of the shaft towards the fixed member during payout of the webbing. Engagement of the coupling with the fixed member prevents further payout of the webbing. The shaft is configured to limit movement of the coupling along the shaft during payout of the webbing to control effective belt force on the vehicle occupant during a crash condition.
19 Citations
18 Claims
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1. A force limiting device for use with a safety belt retractor, the safety belt retractor including a spool, a safety belt webbing attached to and wound around the spool, the spool being rotatable to wind in the webbing and to payout the webbing under the influence of forwardly directed movement of a vehicle occupant, the force limiting device comprising:
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a fixed member; a shaft connected to the fixed member, at least a portion of the shaft is threaded; and a coupling received on the shaft and having an internal thread for threadedly engaging the threaded portion of the shaft, the coupling being configured to move along a longitudinal extent of the shaft, the coupling being operatively connected to the spool and moving towards the fixed member during payout of the webbing, engagement of the coupling with the fixed member preventing further payout of the webbing, wherein the threaded portion of the shaft includes a first threaded section having a first thread pitch and a second threaded section having a second thread pitch, each of the first thread pitch and the second thread pitch differs from a thread pitch of the coupling to limit movement of the coupling along the longitudinal extent of the shaft during payout of the webbing by increasing the force required to turn the coupling on the threaded portion of the shaft, the first threaded section providing a generally constant belt force on the vehicle occupant, the second threaded section providing an increasing belt force on the vehicle occupant. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An attenuated seatbelt stopper operatively connected to a spool of a seatbelt retractor for limiting rotation of the spool during a crash condition, the seatbelt stopper comprising:
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a fixed member; a threaded shaft connected to the fixed member, a section of the shaft having a varying thread pitch along its longitudinal extent for crash performance; and an internally threaded coupling threadedly received on the shaft, the coupling being operatively connected to the spool and moving toward the fixed member during payout of the webbing, engagement of the coupling with the fixed member preventing further payout of the webbing, wherein engagement of the coupling with the varying thread pitch of the shaft increases the force required to turn the coupling on the shaft during payout of the webbing which, in turn, controls effective belt force on the vehicle occupant. - View Dependent Claims (12, 13, 14)
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15. A method of controlling seatbelt force on a vehicle occupant during a crash condition comprising:
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providing a threaded shaft and an internally threaded coupling, the coupling being threadedly engaged on the shaft; operatively connecting the coupling to a spool of a seatbelt retractor such that the coupling moves along the shaft as the spool rotates to payout webbing under the influence of forwardly directed movement of a vehicle occupant; moving the coupling along a longitudinal extent of the shaft; and increasing the force required to move the coupling along the shaft during a crash condition to control a rate of increase of belt force on the vehicle occupant by changing a thread pitch of a portion of the threaded shaft along the longitudinal extent of the shaft. - View Dependent Claims (16, 17, 18)
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Specification