Machine element or mechanism – Mechanical movements – Oscillation or reciprocation to intermittent unidirectional...
Reexamination Certificate
1999-05-26
2001-01-30
Footland, Lenard A. (Department: 3682)
Machine element or mechanism
Mechanical movements
Oscillation or reciprocation to intermittent unidirectional...
C192S043100
Reexamination Certificate
active
06178838
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to an adjusting mechanism, in particular a seat adjusting mechanism for automotive vehicles, comprising a drive member having a toothing and being movable in each of two mutually opposite directions, an actuating member having a neutral position, a guide contour, and two claws movably mounted on said actuating member such that, when the actuating member is moved out of said neutral position in one of said two directions along the toothing of the drive member, one of the two claws meshes with the toothing and the other one is lifted away from the toothing by said guide contour.
An adjusting mechanism of this type is disclosed in Fischer et al. U.S. Pat. No. 5,865,285, wherein the drive member is a gear which is coupled to a seat part to be adjusted through a freewheel brake. When a lever serving as an actuating member is pivoted in any direction out of the neutral position, the one of the claws which then forms the leading claw meshes with the toothing of the gear, so that the gear is rotated and the force is transmitted to the seat part to be adjusted via the freewheel brake. The freewheel brake holds the gear in the position it has reached, when the lever is returned to the neutral position. Thus, the seat part can be adjusted in any desired direction in a step-wise manner by repeatedly rocking the lever. During the return stroke of the lever, the latter is disengaged from the gear because the claw which is then the leading claw is lifted away from the toothing by the guide contour. The claw which at first has been in mesh with the gear could slip over the toothing during the return movement. Then, it would however produce a noise like a ratchet, and this may be disagreeable for the user. For this reason, the known adjusting mechanism provides a spring system which biases the trailing claw away from the toothing during the return stroke of the lever.
However, this construction is relatively cumbersome and further has the drawback that the coupling between the actuating lever and the gear is cancelled as soon as the user interrupts the adjusting movement. Then, the user must at first return the lever to the neutral position in order to re-establish the coupling.
It is an object of the invention to provide an adjusting mechanism of the type indicated above which has simple construction, is easy to operate and the actuating member of which can be returned to the neutral position without producing substantial noise.
SUMMARY OF THE INVENTION
According to the invention, this object is achieved by providing a switching member movable along said toothing and being arranged to be entrained by the movement of said actuating member and to cancel the meshing engagement between said one claw and the toothing when the actuating member returns towards the neutral position.
Thus, during the return stroke of the actuating member, one of the claws is held disengaged from the toothing by the switching member and the other claw is held disengaged from the toothing by the guide contour, so that both claws can move relative to the toothing with low resistance and low noise production. Since the switching member follows the movement of the claws when the actuating member is moved out of the neutral position, it can cancel the engagement between the claw and the toothing irrespective of the position of said claw, as soon as the direction of movement of the actuating member is reversed. When the direction of movement is reversed again, the switching member admits again the engagement between the claw and the toothing, and it is not required that the actuating member is at first returned to the neutral position.
Preferably, the switching member has ramp surfaces which co-operate with the claws or, more precisely, with cams provided on these claws, in a similar way as the stationary guide contour. The path of movement of the switching member is preferably determined by stationary guide means which extend in parallel with the toothing of the drive member and may be provided on the same component member as the stationary guide contour. Advantageously, the switching member is biased to be in frictional engagement with the guide means. Thanks to this frictional engagement, a relative movement between the claws and the switching member can be caused when the direction of movement of the actuating member is reversed, so that the claw or the cam thereof slides onto the ramp surface of the switching member and is thereby lifted off from the toothing. If the claws are elastically biased towards the toothing, as is common practice in the art of such actuating mechanisms, then this bias can at the same time be used for clampingly holding the switching member against the guide means.
The drive member may be an externally toothed gear. It may however also be formed by an internally toothed ring rear or by a straight tooth rack. In case of an internally or externally toothed gear, the switching member may optionally be mounted to be pivotable about the axis of this gear.
REFERENCES:
patent: 5248017 (1993-09-01), Schwarzbich
patent: 5794479 (1998-08-01), Schwarzbich
patent: 5865285 (1999-02-01), Minkenberg et al.
patent: 298 02 055 (1998-02-01), None
Burns Doane , Swecker, Mathis LLP
Footland Lenard A.
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