192 clutches and power-stop control – Clutch and brake – Automatic check and release
Reexamination Certificate
1999-12-13
2001-07-03
Estremsky, Sherry (Department: 3681)
192 clutches and power-stop control
Clutch and brake
Automatic check and release
C297S36700R
Reexamination Certificate
active
06253894
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an adjustment drive acting on both sides. A drive of this kind is suitable in particular for use in a manual height or incline adjustment device for a vehicle seat.
BACKGROUND OF THE INVENTION
From DE 195 27 912 A1 a drive acting on both sides is known wherein the drive lever is mounted on a drive axle and supports swivel locking elements whose free ends are provided with toothed elements that can be brought into engagement with the gearing mounted on the circumference of a drive wheel. A slide guide is associated with the swivel locking elements and lifts the relevant unloaded locking element away from the gearing of the drive wheel depending on the swivel direction of the drive lever. Spring areas are thereby provided both sides and outside the slide guide to exert on the locking elements a force which is directed against the engagement direction of the teeth whereby so-called ratchet noises are avoided.
In one embodiment the gearing provided on the circumference of the drive wheel has internal teeth and the locking elements are mounted on an axis of the drive lever inside the circumference formed by the internal teeth.
One disadvantage with the adjustment drives known from DE 195 27 912 A1 is, on the one hand, the relatively large number of parts. More particularly two independent locking elements are required for an adjustment acting on both sides. This also entails a correspondingly large structural space for the adjustment drive. On the other hand a relatively expensive construction is required in order to provide a defined guide for the locking elements and to avoid the teeth of the locking elements catching on the teeth of the drive wheel as the drive lever is returned to the neutral position. JP A 05176819 describes an adjustment mechanism for adjusting the incline of the seat back of a vehicle seat wherein on operating an operating lever an unlocking action occurs and free adjustment of the incline of the seat back can then be carried out. On releasing the operating lever renewed locking occurs. For locking, two locking parts coupled to the operating lever and mounted rotatable on a spindle are provided with toothed areas which can be brought into engagement with counter teeth and can be brought out of and into engagement with the counter teeth by operating and releasing the operating lever accordingly.
SUMMARY OF THE INVENTION
The object of the invention is to provide a drive operating on both sides to produce a rotary movement which has a low number of individual parts, which is easy to fit and which is characterized by a compact structure.
The solution according to the invention proposes using, as the locking means, a one-piece tilt element which can be tilted to and fro between two end positions and which in each end position according to the existing drive direction transfers a torque to the drive wheel. The use of two separate locking elements is hereby unnecessary and the structural space required is minimized.
At the same time, compared with the use of two separate locking elements, the fitting expense is reduced since riveting the locking elements to the drive lever is eliminated.
As a result of the forces engaging on the tilt element tilting the tilt element can only take place when the swivel movement of the drive lever is out of the neutral position. During a resetting movement of the drive lever, the tilt element automatically comes out of engagement with the teeth of the drive wheel so that it is ensured that the drive wheel is not entrained during the resetting movement.
In a preferred embodiment of the invention, the tilt element is mounted to tilt on two radially spaced bearing points of the drive. The two bearing points are formed on two drive parts which can swivel independently of each other about the drive axis. The one bearing point is thereby formed, in a preferred design, on the drive lever and the other bearing point is formed on a holding plate. The holding plate, on the driven side, adjoins the drive lever wherein the drive lever and holding plate are coupled together by the tilt element.
As a result of the radial spacing between the two bearing points, during operation of the drive lever from the neutral position, a torque is exerted on the tilt element so that the latter tilts in dependence on the drive direction into one or the other end position and comes into engagement with the teeth of the drive wheel. A tilt movement of the tilt element is thereby caused in that during a swivel movement of the drive lever from the neutral position, the bearing point formed on the drive lever is likewise swivelled while the bearing point formed on the holding plate first jams in its position and thereby produces a counter moment.
The holding plate jams as a result of the inertia as well as through the friction forces in its starting or neutral position whereby the tilt element tilts. After the tilt element has tilted into the corresponding end position and has passed into engagement with the teeth of the drive wheel, as a result of the coupling between the drive lever and holding plate, a rotary movement of the holding plate takes place.
In an advantageous development of the invention, the tilt element represents a rocker arm which has two spaced toothed areas arranged on the circular circumference. In each end position of the rocker arm one of the toothed areas thereby comes into engagement with the teeth of the drive wheel. The rocker arm is preferably constructed axially symmetrical whereby the two bearing points of the rocker arm lie on the axis of symmetry. It is hereby guaranteed that the drive functions in the same way in both drive directions.
Alternatively the rocker arm is designed asymmetrically so that a different play between the rocker arm and drive wheel and different lift angles exist in the two drive directions. This design is advisable if a different lift is to be produced depending on the drive direction.
In one embodiment of the invention it is proposed that the toothed areas of the rocker arm as well as the teeth of the drive wheel are not actually formed as cogs but are formed flat. The relevant surfaces have, however, a high coefficient of friction so that a locking of the rocker arm with the drive wheel takes place through friction engagement. The advantage with this design is that no teeth have to be formed on the rocker arm and drive wheel.
In a first variation of the invention, means are provided which, during swivel movement of the drive lever out from the neutral position, counteract a corresponding rotation of the holding plate out from its neutral position. A jamming or brake action of the holding plate of this kind is advantageous since the counter moment is thereby provided on the tilt element or rocker arm for a secure engagement of the toothed areas of the tilt element with the teeth of the drive wheel. Different embodiments are provided for producing such an action of the holding plate.
In a first embodiment, a rotary spring is provided which is fixed on the holding plate. During rotation of the holding plate, the rotary spring is tensioned so that a resetting moment acts on the holding plate in the direction of the neutral position. The rotary spring thus tries to hold the holding plate constantly in the neutral position. With a deflection of the drive lever and a torque exerted on the holding plate as a result of the coupling between the drive lever/tilt element/holding plate, the rotary spring, as a result of its torque acting in the opposite direction on the holding plate, produces a counter moment which leads to a secure tilt and engagement of the tilt element.
In a second embodiment, a counter moment is only produced in the neutral position of the holding plate. To this end a detent element is provided in which the holding plate catches detachably in the neutral position. The detent element is preferably a detent spring which exerts an axial force on the holding plate and through a friction or brake moment connected therewith counteracts the holding plate turn
Forkel Michael
Schumann Peter
Brose Fahrzeugteile GmbH & Co. KG Coburg
Christie Parker & Hale LLP
Estremsky Sherry
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