GB2142079A

GB2142079A - Clamping device for the adjustment means of vehicle seats

Info

Publication number: GB2142079A
Application number: GB08414090A
Authority: GB
Inventors: Manfred Rink; Helge Pietsch; Christian Suss
Original assignee: Isringhausen GmbH and Co KG
Current assignee: Isringhausen GmbH and Co KG
Priority date: 1983-06-03
Filing date: 1984-06-01
Publication date: 1985-01-09
Also published as: GB2142079B; YU92084A; JPS6012348A; FR2547078B1; SE8402884L; AU572843B2; BR8402646A; FR2547078A1; AU2879084A; ES288704Y; YU44233B; SE458192B; GB8414090D0; SE8402884D0; ES288704U

Abstract

A clamping device is for the adjustment means of vehicle seats and, in particular, for clamping against the clamping rods of seats. The device clamps by a wedging action and is capable of transmitting large forces but is easily released under load. Wedge surfaces 11, 12 are formed on a movable securing member 5 which moves at right angles to the axis of the rod 7 eg acted on by eccentric 6 on shaft 6a and cooperate with surfaces 13, 14 on a clamping member 8 to cause clamping engagement of the member 8 with the rod 7. A restoring element 17, 18 acts between members 5 and 8. <IMAGE>

Description

SPECIFICATION Clamping device for the adjustment means of vehicle seats This invention relates to a clamping deviceforthe adjustment means of vehicle seats. The invention is applicable to the continuous adjustment of vehicle seats of the kind described in German Patent Specification No. 31 30 444. The locking spring described in this specification is, however, incapable of transmitting sufficiently large forces to the rod and does not, therefore, fulfil the safety requirements for vehicle seats.

Devices for the clamping of rods are known which act by a wedging action. Such devices are capable of transmitting large forces to the rod but have the disadvantage that, after wedging, the clamp is difficult to release and is often impossible to release under load. Release under load is, however, necessary for vehicle seats since the occupant effects adjustment of the height and inclination of the seat when he is seated on it and the part of the seat to be adjusted, fitted with the rod adjustment device, is loaded with the weight of the occupant.

An object of the invention is to provide means for clamping a rod adjustment device for vehicle seats which is able to transmit the high forces necessary on vehicle seats and is also capable of being released without difficulty in the loaded condition of the seat during normal use.

According to the invention a clamping device for the adjustment means of vehicle seats comprises a housing through which a rod of the adjustment means is located, a clamping member movably mounted in the housing and having two clamping faces one of which is arranged for clamping engagement with the rod, a securing member having a surface engageable with the other clamping face of the clamping member to define cooperating wedging surfaces at an acute wedging angle to the axis of the rod, the securing member being movable at a right angle to the axis of the rod, and a restoring element acting in a direction of increase of the wedging angle of the wedging surface.Such a device operates by a wedging action and is therefore able to transmit high clamping forces to the rod which in use is fixed to the vehicle seat or to the seat sub-frame, and secure clamping of the adjustment device of the seat is assured during normal driving conditions and also in an emergency when high braking takes place or when a traffic accident arises.

The device is capable of being released easily, even when under load. For this purpose the securing member is pulled away from the rod by a device at a right angle to the axis of the rod so that the clamping member which engages the rod is released and, by the use of a restoring element acting in the direction of release of the wedging action which is withdrawn automatically into a starting position, the clamping device is ready to function again to clamp the rod.

Further clamping takes place when the securing device is moved towards the rod and the clamping member is engaged with the rod.

Preferably the clamping member is attached to the securing member for movement relative thereto. In this way the clamping member, together with the securing member, are pushed positively towards or away from the rod and a reliable release of the clamping device is ensured.

The clamping device may be single or doubleacting. In a double-acting arrangement the clamping member and the securing member may be symmetrical about an axis of symmetry lying perpendicular to the axis of the rod and the securing member has symmetrical wedging surfaces which are each formed as part spherical surfaces, and the restoring element is arranged as a centering element for the securing member and the clamping member.

Conveniently the restoring element includes a metal spring, and the clamping face of the clamping member engageable with the rod is slip-resistant and preferably toothed. By the use of a metal spring the adjustment movement of the clamping member on the securing member needs only to be small under normal loading of the device, so that it is possible in the normal case to regard the clamping of the device on the rod as being practically free from play. Freedom from play is also assisted if the clamping surface of the clamping member engaging the rod is slip-resistant and, preferably, toothed.

When an emergency, such as emergency braking of the vehicle, takes place, the metal spring is more strongly extended and a greater movement of the clamping member on the securing device takes place. In this case a greater wedging action of the clamping member occurs and high clamping forces are transmitted to clamp the device on the rod and accept the resulting higher load.

The securing member may be displaced by means of an adjustable spindle which is generally selflocking in all adjustment positions. Conveniently the locking means includes eccentric drive means which attains a dead point postion when the securing member is pushed forward against the rod. The locking means should attain its dead point when the securing means has been moved forward to the maximum extent and high loads can be accepted in the dead point position.

The clamping device can be used with any kind of rod but it is preferred that the rod is of rectangular cross-section due to the larger contact surface between the clamping member and the rod.

The device may comprise a spring by which the securing member is retained in a position pushed forward towards the rod, and an actuating device by which the securing member is movable away from the rod against the action of said spring. By this means the device is biased towards a clamping position and is opened against the spring action for a seat adjustment, for example for adjustment of the seat back rest inclination, to take place.

Preferably the spring is a compression spring carried on a guide rod located coaxially of the spring.

This arrangement gives enhanced safety and the spring remains capable of functioning even if the spring breaks, and the device remains in a clamped condition.

To operate the device various kinds of Bowden cables can be employed. Alternatively electro magnetic or hydraulically-operated devices can be used. Moreover pneumatically-operated cylinders supplied by compressed air, available on many vehicles, can be employed and can be operated easily by valves.

Embodiments of the invention will now be described by way of example only and with reference to the drawings, in which: Figure 1 is a cross-section through one embodiment of clamping device, Figure 2 is an external plan view of the device of Figure 1, Figure 3 is an external side elevation of the device of Figure 1, Figure 4 is a cross-section of part of a further embodiment of clamping device, Figure 5 is a plan view of the part shown in Figure 4, Figure 6 is a side elevation of the part shown in Figures 4 and 5, and Figure 7 is a plan view, corresponding to Figure 2, showing an alternative arrangement to that shown in Figure 2.

Referring to the drawings and firstly to Figures 1-3 a clamping device includes a housing 4 having a securing member or slide ring 5. The member 5 is adjusted by an eccentric 6 and a clamping member8 is arranged between the securing member 5 and a rod 7 to be clamped.

The securing member 5 is mounted for movement within the housing in a direction at a right angle to the axis of the rod 7. Such movement is effected by the eccentric 6 mounted on an eccentric shaft 6a which extends out of the housing 4 and carries an externally-located adjustment lever 9 (Figures 2 and 3). The lever 9 is biased by a spring 10 towards a position in which the securing member 5 is urged towards the rod 7.

In Figure 1 the securing member 5 is shown moved forward by its maximum extent and the eccentric 6 is in its dead point position. In this position the device is capable of accepting high loads at a right angle to the axis of the rod 7.

The securing device 5 has two wedging surfaces 11 and 12 which, in the illustrated embodiments, are combined and are in the form of part spherical surfaces. The clamping member 8 has corresponding clamping surfaces 13 and 14formed as a corresponding part of a spherical surface. Clamping faces 15 and 16 of the clamping member 8 are directed against the rod 7 and are formed as toothed surfaces to provide for adequate grip on the rod.

The clamping member 8 is attached to the securing member 5 by a screw 17 and an elastic element 18, together acting as a restoring element. The restoring element ensures that the faces 11, 12 and 13, 14 always remain in contact with one another but adjustment of the surfaces in the direction of the circular arc can take place by reason of the elastic element 18. For this purpose a bore 19 in the clamping member 8 is larger than the shank of the screw 17.

When the clamping member 8 is not applied against the rod 7 the elastic element 18 generally centers the surfaces of the clamping member 8 and the securing member 5. Such centering of the surfaces can be achieved by other means such as a spiral our a leaf spring.

Referring now to Figures 4-6 another embodiment of clamping device is shown which, in most aspects, is similartothat of Figures 13, and in Figures 4-6 the housing 4 and rod 7 are not shown. The restoring element of the embodiment of Figures 4-6 is in the form of a metal spring 28. A clamping member 24 is movably supported by a securing member 25 by the provision of side flanges 26 on the clamping member 24 which engage with a side flange 27 of the securing member 25. The spring 28 is U-shaped and double-acting and is located in a recess in the side flanges 26 and 27, the arms 29 and 30 of the spring 28 centering the clamping member 24 on the securing member 25.

When the clamping device is in a closed or rest position the clamping member 8 (Figures 1-3) of the clamping member 24 (Figures 4-6) is applied against the rod 7 and the device is retained in this position by a tension spring 10 (Figures 2 and 3). In Figure 7 is shown an alternative arrangement in which the tension spring is replaced by a compression spring 31 which is located on a coaxial guide rod 32. The rod 32 is pivotally attached to an adjustment lever 33 at one end and at the other end the rod 32 is movably mounted on a plate 34 against which the spring 31 engages. In this way, even in the event of the spring 31 breaking, it remains capable of urging the device towards a closed position.

The clamping device is released from the rod by moving the eccentric 6 away from its dead point position by operation of a Bowden cable 23 (Figures 2 and 3) to rotate the shaft 6a. The sleeve 20 of the Bowden cable 23 is supported on a pin 21 mounted on the housing 4 and the traction cable 22 is attached to the adjustment lever 9 (Figure 2) or the adjustment lever 33 (Figure 7).

Claims

1. A clamping device for the adjustment means of vehicle seats comprises a housing through which a rod of the adjustment means is located, a clamping member movably mounted in the housing and having two clamping faces one of which is arranged for clamping engagement with the rod, a securing member having a surface engageable with the other clamping face of the clamping member to define cooperating wedging surfaces at an acute wedging angle to the axis of the rod, the securing member being movable at a right angle to the axis of the rod, and a restoring element acting in a direction of increase of the wedging angle of the wedging surfaces.

2. A device according to claim 1 wherein the clamping member is attached to the securing membey for movement relative thereto.

3. A device according to claim 1 or 2 wherein the clamping member and the securing member are symmetrical about an axis of symmetry lying per pendicularto the axis of the rod and the securing member has symmetrical wedging surfaces which are each formed as part spherical surfaces, and the restoring element is arranged as a centering element for the securing member and the clamping member.

4. A device according to claim 1, 2 or 3 wherein the restoring element includes a metal spring, and the clamping face of the clamping member engageable with the rod is slip-resistant and preferably toothed.

5. A device according to claim 3 or 4 wherein the restoring element is formed as a U-shaped resilient metal element the arms of which center the clamping member relative to the securing member.

6. A device according to any one of the preceding ciaims wherein the securing member is movable within the housing at a right angle to the axis of the rod by locking means which is self-locking at least in a position in which the securing means is urged towards the rod.

7. A device according to claim 6 wherein the locking means includes eccentric drive means which attains a dead point position when the securing member is pushed forward against the rod.

8. A device according to any one of the preceding claims comprising a spring by which the securing member is retained in a position pushed forward towards the rod, and an actuating device by which the securing member is movable away from the rod against the action of said spring.

9. A device according to claim 8 wherein the spring is a compression spring carried on a guide rod located coaxially of the spring.

10. A device according to claim 8 or 9 wherein the actuating device includes a Bowden cable.

11. A device according to claim 8 or 9 wherein the actuating device includes a pneumaticallyoperated cylinder.

12. A clamping device for the adjustment means of vehicle seats substantially as described with reference to Figures 1,2 and 3 or Figures 4, and 6, or as modified according to Figure 7 of the drawings.