US 5,964,442 AGranted

Vehicle seat adjuster with self compensating cross wire length

AssigneeLear Corporation

InventorsGlen Daniel Wingblad, Gary Paul Parko, Robert Paul Adams

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Abstract

A cross wire linked between master and slave lock bars of a vehicle seat adjuster assembly has a normally fixed length, but can lengthen when needed to accommodate a wide build condition of the parallel seat tracks. The fixed length of the cross wire is set so as to accommodate every condition but for master lock bar opening at wide build, when the slave lock bar will fully open before the master lock bar has fully opened. At that point, and only at that point, a central, integral coil spring in the cross bar, which is preloaded to match the fully open return spring force of the slave lock bar, stretches and allows the whole cross wire to effectively lengthen. The master lock bar can then be fully opened without overstressing the wire.

Claims3

Dependent claims

A seat adjuster assembly for a vehicle seat having a pair of substantially parallel seat tracks having a spacing that varies within a known manufacturing tolerance range from a nominal, least value to a greatest value, and in which a master lock bar associated with one track is operated directly by an adjuster mechanism that rotates said master lock bar between closed and open positions while a slave lock bar associated with the other track rotates simultaneously between closed and open positions in tandem with the master lock bar, and in which the slave lock bar has a resilient return spring that produces a predetermined return force when fully opened, and a means for connecting said master and slave lock bars that compensates for the tolerance variation in said track spacing, comprising,

a cross wire having solid end portions connecting to respective ones of said lock bars and a central, fixed length preload means interconnecting said cross wire ends, said preload means being pretensioned sufficiently so as to maintain its fixed length until a threshold level of tension is applied thereto substantially equal to said predetermined slave lock bar return force, said cross wire having an initial, end to end length sufficiently long to allow both of said lock bars to remain substantially fully closed when said tracks are spaced at the high end of said tolerance range but short enough to pull said slave lock bar fully open when said tracks are spaced at the low end of said tolerance range, and, therefore, also short enough, when said tracks are spaced at the high end of said tolerance range, to pull said slave lock bar fully open when said adjuster mechanism has only partially opened the master lock bar,
whereby, when said tracks are spaced at or near the low end of said tolerance range, said cross wire will open said slave lock bar without lengthening, and when said tracks are spaced at or near the high end of said tolerance range, said threshold level of tension will be exceeded when said slave lock bar is fully opened, allowing said central preload means to lengthen and thereby allowing said adjuster mechanism to rotate the master lock bar fully without overstressing said cross wire.

a cross wire having solid end portions connecting to respective ones of said lock bars and a central coil spring interconnecting said cross wire ends, said coil spring being pretensioned sufficiently so as to maintain its coils in a solid, unstretched condition until a threshold level of tension is applied thereto substantially equal to said predetermined slave lock bar return force, said cross wire having an unstretched, end to end length sufficiently long to allow both of said lock bars to remain substantially fully closed when said tracks are spaced at the high end of said tolerance range but short enough to pull said slave lock bar fully open when said tracks are spaced at the low end of said tolerance range, and, therefore, also short enough, when said tracks are spaced at the high end of said tolerance range, to pull said slave lock bar fully open when said adjuster mechanism has only partially opened the master lock bar,
whereby, when said tracks are spaced at or near the low end of said tolerance range, said cross wire will open said slave lock bar without stretching, and when said tracks are spaced at or near the high end of said tolerance range, said threshold level of tension will be exceeded when said slave lock bar is fully opened, allowing said coil spring to stretch and thereby allowing said adjuster mechanism to rotate the master lock bar fully without overstressing said cross wire.

Dependencies are inferred from the claim text.