Chairs and seats – Movable back – Tiltable
Reexamination Certificate
1999-11-15
2001-07-31
Brown, Peter R. (Department: 3636)
Chairs and seats
Movable back
Tiltable
C192S223000
Reexamination Certificate
active
06267444
ABSTRACT:
DESCRIPTION
The invention relates to a two-way drive according to the introductory clause of claim
1
. A drive of this nature is particularly suitable for use in a manual adjustment device for raising or inclining a vehicle seat.
DE 43 09 334 A1 disclosed a two-way drive whereby force is transferred from a drive lever to a shaft which is to be driven, whereby this force transfer takes place through friction locked components positioned on the shaft. Upon entering the drive phase, the friction locked components have friction-dependent self-locking with the upper surface of the shaft which is to be driven. It is thereby ensured that the friction torque increases dependent upon the drive torque, whereby great forces can also be transferred. Upon reverse movement of the drive lever in the direction of its zero position, however, the self-locking is released and the friction torque is kept as low as possible.
The conditions for self-locking are controlled by an elastic switching component. If the drive lever swings over its zero position, this leads to expansion of the elastic switching component which is formed in particular as a wire-form spring. The tangentially working force thereby produced gives rise to tilting and tensioning processes within the clearance area of the drive mechanism, in such a way that self-locking can come into effect and be increased.
When the drive lever returns to the zero position, one spring end of the elastic switching component exerts a tangential force on the friction locked components by means of a bolt, whereby this tangential force works in the swing direction of the drive lever and releases the self-locking properties in such a way that the shaft is prevented from clamping or turning backwards.
Two-way drives of the nature described in DE 43 09 334 A1 generally have—in addition to the components described there—a return spring for returning the drive lever to its zero position. The return spring is thereby supported on the one hand on a fixed casing catch and on the other hand it is coupled with a return catch which is directly secured to the drive lever. A return spring of this nature is for example described in DE 195 27 912 A1.
Existing two-way drives of the afore-mentioned nature thus have two spring components—a spring component for returning the drive lever to its zero position and a spring component (elastic switching component) for engaging the friction locked components with the shaft.
On the basis of this existing technology, it is an object of the present invention to create a two-way drive for producing a rotation movement, whereby this drive is flat and compact and is characterised by few components.
The solution according to the invention provides that the return catch which is coupled with the return spring is secured to one of the friction locked components. The return spring thereby serves as an elastic switching component. In other words, when the drive lever moves away from the zero position, the return spring causes the friction locked components to engage with the shaft. At the same time, the return spring is used for returning the drive lever to its zero position, whereby the friction locked component connected to the return catch itself has a friction locked and/or a shape locked connection with the drive lever, in such a way that a restoring force is transferred through the friction locked component to the drive lever.
According to the invention, the return catch is secured to one of the friction locked components, which means that the return spring performs a dual function. Besides the restoring function, it also performs the function which in the current state of technology has been performed by a specially provided elastic switching component. This function consists in bringing about self-locking of the friction locked components with the upper surface of the shaft which is to be driven, when the drive lever moves away from the zero position. There is thus no need for a separate elastic switching component to perform the latter function.
The omission of a separate elastic switching component means that all in all the drive can be flatter and more compact. The space requirement is reduced. By reducing the components, the tolerance chain, i.e. the sum of the maximum tolerances between the individual components, is also reduced. This means that the clearance area of the drive lever is reduced.
Reference is made to the fact that the use of the clamping principle disclosed in DE 43 09 334 A1 is unchanged in the present invention. With regard to the corresponding configuration of the individual friction locked components and the way in which they are linked together, reference is made to this document in this respect.
In a preferred embodiment of the invention, the return spring is positioned on the output side on a brake box. The brake box contains a brake mechanism, which is connected to the shaft in such a way that a torque transfer on the output side is blocked, whereas a torque transfer on the drive side releases the blocking effect. A blocking mechanism of this nature is for example described in DE 41 20 617 A1.
Between the friction locked components positioned on the shaft axis and the brake box there is preferably a mounting support, by means of which the two-way drive can be secured to a support component, for example a vehicle seat. The fixed casing catch which is connected to the return spring is thereby preferably secured to/formed on the brake box or the mounting support. The casing catch thereby forms a fixed position upon which the spring supports itself.
The return spring is preferably constituted by a coil-like torsion spring or a wire-form spring with two free ends which are connected to the casing catch/the return catch. Springs of this nature allow a tangentially working force to be simply produced. In addition, the components are relatively easy to manufacture and cost-effective.
The return catch is advantageously formed as a plate, which is formed on the corresponding friction locked component, extends from this friction locked component to the restoring spring and is connected to one free end of the restoring spring. The friction locked component equipped with the return catch is thereby preferably formed as a component which is stamped and bent. This facilitates cost-effective manufacture of the friction locked component, whereby the return catch is manufactured in a straightforward way by stamping and bending.
In a preferred embodiment of the invention, a total of three friction locked components are provided. They are positioned on the shaft axis and for the purpose of engaging with the shaft they are linked to one another, as for example described in DE 43 09 334 A1.
In a preferred configuration of this embodiment of the invention, the middle friction locked component is formed as a sinter component and the two side-positioned friction locked components are formed as sheet metal components. The sinter component is thereby equipped with bolts which engage corresponding bores of the two side-positioned friction locked components, and provide a link between the middle friction locked component and the respective side-positioned friction locked components. When the drive lever is activated from its zero position, the side-positioned friction locked components tilt in relation to the middle friction locked component, whereby they clamp the shaft which is to be driven.
The respective friction locked components are preferably in ring form and have inner force application areas, which can engage with the cylindrical contour of the shaft. Reference is again made to DE 43 09 334 A1 in this respect.
If the friction locked components are manufactured from sheet metal, for the purpose of linking the individual friction locked components together, the latter are preferably equipped with components which are put through, plates and/or embossed components. Friction locked components of this nature can be manufactured simply and cost-effectively and they allow the individual friction locked components to be linke
Brose Fahrzeugteile GmbH & Co. KG Coburg
Brown Peter R.
Christie Parker & Hale LLP
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