Brakes – Operators – Seat
Reexamination Certificate
1999-08-11
2001-07-17
Oberleitner, Robert J. (Department: 3613)
Brakes
Operators
Seat
C248S422000, C248S419000, C297S344130, C297S344170
Reexamination Certificate
active
06260672
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a vehicle seat with an adjusting mechanism, for example with a height adjustment of the seat area or with a length adjustment of a longitudinal guiding, whereas the adjusting mechanism is provided with an electromotor, a step-down gear and an adjusting device having a first adjusting element as well as a second adjusting element which may be adjusted relative to the first adjusting element.
Vehicle seats with one or several adjusting mechanisms are state of the art. They make it possible to achieve an ergonomic adjustment of the vehicle seat and are thus contributing to safety. Compared to mechanical adjusting mechanisms they may particularly be adjusted in a more comfortable way that requires less effort. This makes them more comfortable to use.
Generally, a problem arises with these adjusting mechanisms. In the normal operating state of the vehicle seat, either in positive or negative accelerations in or across the driving direction or under stress, forces are acting between the two adjusting elements and are trying to disarrange them relative to one another. This entails at least small relative movements between the two adjusting elements. A small jerk is thus occasioned that may more or less be felt by the user. It particularly leads to a sound, for example to a click. The object of the invention is to find a remedy hereto.
Generally, the couples of rails of a length adjusting device used to adjust in length the vehicle seat are arranged diagonally to the horizontal plane. As soon as a vehicle seat is loaded with a passenger, relative forces are occurring between the two adjusting elements, in this case between the seat rails and the bottom rails of the length adjusting device. Yet also while driving, for example when braking or taking a curve, forces are trying to move the two adjusting elements relative to one another.
Similar problems arise also with other adjusting mechanisms of a vehicle seat, for example with a height adjustment of the seat, an angle adjustment of the backrest and so on. Here too, relative forces are already occurring under normal driving conditions, as well as when the seat is loaded with a passenger, when driving on a bad surface, and so on.
By an adjusting device with a first and a second adjusting element the following is meant: the two adjusting elements are guided mechanically relative to one another, they are for example linked to each other or may be longitudinally displaced relative to one another. Additionally, they are provided with driving parts as for example a pinion pertaining to the first adjusting element and a toothed rack pertaining to the second adjusting element, or, in the same way, a spindle and a spindle nut and so on. The adjusting device thus comprises the parts that have to be mechanically adjusted relative to one another as well as the driving parts for this mechanical adjustment.
SUMMARY OF THE INVENTION
On the basis thereof the object of the invention is to develop the adjusting mechanism of the type mentioned above so that the relative forces occurring between the two adjusting elements during normal operation of the vehicle become unnoticeable, in the relative movement between the two adjusting elements as well as acoustically.
By normal operating state of the vehicle are meant all the states below accelerations due to an accident, that is in situations in which the electronics of an air bag and other safety electronics reacting in case of an accident have not yet been triggered.
The solution of the invention is to additionally provide the adjusting mechanism with a constantly engaged brake that is leading to a braking moment in both senses of rotation of the electromotor, the braking moment being calculated so as to be considerably smaller than the active driving moment of the electromotor at its place, but so as to be bigger than the passive torques occurring during normal operation of the vehicle due to all kinds of acceleration and loads.
The brake according to the invention is thus initiating such a high braking moment on one shaft of the adjusting mechanism that all forces occurring between the two adjusting elements during normal operation are leading to torques on the same shaft, said torques being smaller. By this means, undesired and involuntary passive torques are not leading essentially to relative movements between the two adjusting elements. The torque initiated by the electromotor on the shaft is far bigger than the braking moment of the brake. Thus, the adjusting mechanism is always adjusted when the electromotor is actuated.
In a preferred formation, the brake is situated in the range of a small number of revolutions, that is for example between the step-down gear and the adjusting device. Thus, length adjusting devices for example are typically working with a motor-driven pinion being in mesh with a toothed rack. Typically, the brake is then located between pinion and step-down gear.
In a preferred embodiment, the braking moment of the brake is the same in both senses of rotation. On one hand this leads to a simpler design of the brake, on the other hand it may happen that in practice the accelerations and loads are occurring in all possible directions and that they have to be intercepted.
In a preferred embodiment the brake has a dynamometer that is working as a clamping member and that encompasses a cylindrical part of the shaft to be braked by sparing a slot running on an axial plane. The dynamometer is preloaded by means of a flexible means so that the slot is compressed. Between the cylindrical part of the shaft to be braked and the dynamometer two surfaces are in contact and are sitting close to each other with friction. The friction surface preferably has a friction member of its own arranged in the dynamometer, the inner surface of said friction member constituting the friction surface of the dynamometer.
The dynamometer has appropriate fastening means, so that it may be fastened on a gear or on the mechanical part of the adjusting device into which the actuation is triggered. In a preferred embodiment the friction surface is constituted between a steel tube on one side and a particularly duroplastic synthetic on the other or between an aluminium tube on one side and again a synthetic, more particularly a duroplastic on the other side. The friction surface may also be formed by a magnetic slot and constitute a so-called magnetic-particle brake.
Further advantages and characteristics of the invention will become clear in the other claims and in the description of the embodiments of the invention.
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patent: 4966045 (1990-10-01), Harney
patent: 5427345 (1995-06-01), Yamakami et al.
patent: 5762309 (1998-06-01), Zhou et al.
patent: 5871195 (1999-02-01), Gauger
patent: 5876096 (1999-03-01), Yamakami
patent: 5882075 (1999-03-01), Partington et al.
patent: 5899428 (1999-05-01), Gauger
patent: 5909866 (1999-06-01), Vaidyanathan et al.
Becker Burckhard
Frohnhaus Ernst-Reiner
Lingner Michael
Cornaby K. S.
Kramer Devon
Oberleitner Robert J.
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