GB2326188A

GB2326188A - Locking mechanism for a head restraint

Info

Publication number: GB2326188A
Application number: GB9819636A
Authority: GB
Inventors: Bjoern Albrecht
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 1995-06-28
Filing date: 1996-06-27
Publication date: 1998-12-16
Anticipated expiration: 2016-06-27
Also published as: GB2326188B; GB9819636D0

Abstract

A locking mechanism for a head restraint (7) which can be locked in a frame (8) of a seat, in particular a vehicle seat, via at least one retaining bar (5, 6), comprises an operating element (15) which interacts with at least one interlocking element (21) such that the head restraint can be latched at various heights. The operating element, which may be formed as a push button (15), is at least indirectly retained on a frame (8) of the head restraint. The frame also at least indirectly retains a cushion element (9).

Description

DESCRIPTION LOCKING MECHANISM FOR A HEAD RESTRAINT The present invention relates to a locking mechanism for a head restraint.

The present application is a divisional from GB9613495.2 (publication no. 2302706) in which is claimed a head restraint of the generic type discussed herein, having an operating element which interacts with an interlocking element to latch the head restraint, a force-transmission element being arranged within the retaining bar, being at least indirectly acted upon at one end region by the operating element and at the other end region being at least indirectly operatively connected to a blocking element which penetrates the retaining bar, is configured for latching in a latching socket fixed on the seat, and is effective as an interlocking element.

In modern car manufacturing, in particular, use is made of head restraints which are connected to a vehicle seat in a manner such that they are released for adjustment and positioning purposes or are fixed on the framework by actuating a locking mechanism. Thus, for example, DE-34 36 541-C1 (B60N 1/06) discloses a locking mechanism with an operating element, the sliding guide of which is arranged approximately parallel to the sliding guide of the head-restraint retaining bar to be locked in place. Alternatively to this, designs have also been disclosed in which the operating element can be moved essentially at a right angle with respect to the axis of the head-restraint guide (cf., in this connection, for example, DE-36 36 931-Cl; B60N 1/06). Such concepts have basically been proven in practice. However, ever increasing requirements for operational convenience, on the one hand, and for constructions of the lightest possible weight, on the other hand, necessitate further optimization of such head restraints.

An aim of the present invention is therefore to develop a generic locking mechanism with regard to the abovementioned requirements in a manner such that an improvement is obtained at least in the case of one of the aspects of light weight or convenience without any impairment to the other requirement in each case having to be accepted.

According to the present invention there is provided a locking mechanism for a head restraint which is at least indirectly retained in a framework part of a seat, in particular a vehicle seat, via at least one retaining bar and can be positioned in a latching manner at various heights by means of an operating element which interacts with at least one interlocking element, a force-transmission element arranged within the retaining bar, being at least indirectly acted upon at one end region by the operating element and at the other end region being at least indirectly operatively connected to a blocking element which penetrates the retaining bar, is configured for latching in a latching socket fixed on the seat, and is effective as an interlocking element.

According to a further feature of the present invention there is provided a locking mechanism for a head restraint which is at least indirectly retained in a framework part of a seat, in particular a vehicle seat, via at least one retaining bar and can be positioned in a latching manner at various heights by means of an operating element which interacts with at least one interlocking element, in which the operating element is at least indirectly retained on a frame part of the head restraint, which frame part at least indirectly retains a cushion element.

The locking mechanism according to the present invention has, between a blocking element, which is to be locked in place such that it is fixed on the housing, and an operating element, a force-transmission element which is arranged within the retaining bar. In this manner, it is possible for all of the guide elements for the force-transmission element which were hitherto assigned to the vehicle seat to be dispensed with. On the seat, all that is required is the introduction of recesses in retaining-bar guides which are present in any case. The retaining bars' hollow shape which is necessary for the integration of the force-transmission element also results in it being possible to obtain a greater flexural strength with the same outlay on material for the retaining bar itself. According to a particularly advantageous exemplary embodiment of the invention, the force-transmission element is an adjustment rocker lever which can be pivoted within the retaining bar about an axis of rotation running essentially transversely with respect to the axis of rotation of the retaining bar. The adjustment rocker lever is preferably coupled to the operating element via a retaining rod and moves a blocking element which can be moved into an interlocking or release position depending on the operator's requirements. In the particular interlocking positions, the adjustment rocker lever itself is not subject to any relatively great stresses and can therefore be dimensioned such that it is relatively slight and hence lightweight. Moreover, by direct bearing against the inner wall of the retaining bar itself a supporting effect can be produced which likewise permits dimensions to be slight without any impairment in the reliability of the system having to be expected.

Particularly lightweight locking mechanisms can alternatively also be achieved if the forcetransmission element is formed, for example, as a so called Bowden cable or as a combination of operatively connected slave and master pistons.

An improvement in convenience, is obtained according to a further feature of the present invention by virtue of the fact that the operating element is no longer arranged closely above the backrest edge but in the head restraint itself. It is thus possible for convenient single-handed operation to be realized for adjusting the head restraint. By attaching the operating element to a side of the head restraint, the aesthetic effect of the head restraint on passengers within the vehicle is not impaired. Only slight constructional changes are necessary to the headrestraint frame itself in order for it to be possible to adapt head-restraint concepts already in series production to the invention.

Head restraints which are configured according to a combination of the present invention and said further feature of the present invention are particularly advantageous. As a result of this synthesis, the requirements mentioned at the beginning are simultaneously fulfilled.

It should also be emphasized that head restraints configured according to the present invention result in a substantial simplification of the seat construction and also the seat assembly.

The present invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a partial fragmentary view of one embodiment of a locking mechanism according to the present invention; Fig. la is a partial fragmentary view of another embodiment of the present invention; Fig. lb is a partial fragmentary view of a still further embodiment of the present invention; Fig. 2 shows a side view of the locking mechanism illustrated in Fig. 1; Fig. 3 shows a view according to the section III III in Fig. 1; and Fig. 4 shows an overall view of a particularly advantageous exemplary embodiment.

In all the figures of the accompanying drawings, identical components or component segments are identified by the same reference number.

Fig. 1 shows a symbolically represented seat framework frame 1 which is part of a backrest 2 illustrated only in a fragmentary way here. Connected in a positionally fixed manner to the seat framework frame 1 are guides 3 and 4 in which retaining bars 5 and 6 of a head restraint 7, only part of which is illustrated here, can be displaced longitudinally. In a manner known per se, the essential components of the head restraint 7 are a head-restraint frame 8, which holds the retaining bars 5 and 6, and a foam cushion 9 used as a headrest. The parallel arrangement of the retaining bars 5 and 6 is stabilized by a carrier element 10 which is fastened to the respective upper ends of the retaining bars 5 and 6 by means of a retaining link 11 (cf. Figure 3), to be precise, for example, by welding, soldering, tacking or the like.

A dimensionally stable trough body 13 is introduced, in a manner such that it penetrates the foam cushion 9, at one side 12 of the head restraint 7, which trough body engages, via a moulded-on flange 14, behind a specific recess, not numbered here, in the head-restraint frame 8. Within the trough body 13 there is situated, as operating element for a locking mechanism, an actuating knob 15 which is coupled via an actuating or retaining rod 16 to an adjustment rocker lever 17 which, for its part, is mounted pivotably within the retaining bar 6. The pivot mounting takes place via a pivot pin 18 which, for its part, is placed in the retaining bar 6, or in a bearing sleeve 18a fixed therein (cf. Figure 4), either by screwing, pressing or a joining technique comparable therewith.

In the exemplary embodiment illustrated in Figure 1, the retaining rod 16 is attached in a rotationally fixed manner on the adjustment rocker lever 17, with the result that at the same time as the adjustment rocker lever 17 moves into the position indicated by dashed lines, the actuating knob 15 has to pivot. This pivotal motion of the actuating knob 15 is catered for by virtue of the fact that recesses 19 and 20 in the upper end of the retaining bar 3 and in the trough body 13, respectively, are configured such that they are of an appropriately large enough size. As an alternative to this, in the exemplary embodiment illustrated in Figure 4,the recesses 19 and 20 are designed as guide sleeves for the actuating rod 16. The latter acts in the manner of a tipping lever loaded and also retained by a spring 13a, against the upper end of the adjustment rocker lever 17 in a rotating and sliding manner, with the result that the actuating knob 15 acts as a sliding knob. It is also conceivable for the actuating rod 16 to be articulated on the upper end of the adjustment rocker lever 17.

The retaining bar 6 is locked with respect to the seat framework frame 1 via a blocking element 21 which here is fixedly connected to the lower end of the adjustment rocker lever 17 and can be latched into a latching profile of the guide 3, the latching profile being designated as a whole by 22. The blocking position is maintained by means of a compression spring 23 which acts on the lower end of the adjustment rocker lever 17. A helical spring is illustrated here only symbolically but in the same manner leaf springs directly articulated on the adjustment rocker lever 17 or on the retaining bar 6 (cf. Figure 4), or elastic clamping bodies, are also conceivable as spring elements. Instead of a blocking element 21 connected fixedly to the adjustment rocker lever 17 it is also possible for the blocking element 21 to be displaceable against spring force in a longitudinal guide oriented transversely with respect to the axis of rotation of the retaining bar 6. In this case, the lower end of the adjustment rocker lever 17 would then be shaped like a fork or claw and would be able to move the blocking piece, which is configured for displacement, to and fro for the purpose of interlocking or release, respectively.

It is clear from Figures 1 and 4 that only single-handed operation is necessary for adjusting the head restraint 7. By means of the arrangement of the actuating knob 15, which arrangement is provided in the lower region of the head restraint 7, the head restraint 7 itself can, on the one hand, be grasped on its lower side for the adjustment movement by a vehicle passenger and, at the same time, acted on via an actuation with the thumb on the locking mechanism. By means of simple pivoting of the actuating knob 15 into the position illustrated by broken lines, via the simultaneous movement of the adjustment rocker lever 17 according to rotational arrow A about the pivot pin 18, the blocking piece 21 is moved out of the latching profile 22. The spring rate of the spring element 23 is selected in a manner such that, on the one hand, secure locking of the blocking piece 21 in the latching profile 22 is maintained even when the backrest 22 vibrates and, on the other hand, the actuating force to be applied to the actuating knob 15 is not uncomfortably great. After the head restraint 7 has been positioned at the desired height, locking takes place by simple release of the actuating knob 15. The blocking piece 21 then snaps into the latching profile 22 as soon as a corresponding latching recess is opposite it.

It is also of particular significance in this connection that the actuating knob 15 is set back behind the contour of the head restraint 7 within the trough body 13. This measure ensures that the aesthetic overall impression of the head restraint 7 is not adversely affected and, moreover, also that no risk of injury or unintentional manipulation is provoked by protruding parts.

In the view in Figure 3 it can be seen, moreover, that only slight constructional changes have to be undertaken in order to match head-restraint concepts already in series production to the invention. For example, a dashed line 24 shows the contour profile of previous head-restraint frames. Diverging therefrom, with little outlay on tool modification the profile of the head-restraint frame 8 can be set back in accordance with the curved projection 25.

Figures 2 and 3 show that the cavity in the retaining bar 6 has a polygonal cross-section, here to be precise a quadrilateral with rounded edges. A circular or oval cross-section is, however, also conceivable. The retaining bar 6 itself may be configured as a construction of one or two shells.

Figure la shows diagrammatically, as the forcetransmission element,an arrangement comprising a master piston 17a and a slave piston 17b, which are operatively connected via a fluid line 17c. The compression spring 23 bears against a piston plate, not given a number here, in the slave piston 17b and presses the blocking element 21 outwards. By displacing the actuating rod according to arrow A the pressure in the master piston 17a is raised so considerably that the piston plate is moved to the right, pulling, as it does so, the blocking element 21 out of the latching profile 22. In this release position, the head restraint 7 can be adjusted.

As a further variant, Figure lb shows a forcetransmission element in the form of a Bowden cable 17d with a sliding core 17e which acts on a pulling wedge 17f. The latter secures the blocking element 21 in the latching profile 22 via a wedge surface. By moving the pulling wedge 17f in the arrow direction B, after the actuating knob 15 is actuated, the blocking element 21 is pulled into a release position by the tension spring 23'.

It is clear from the view in Figure 1 that the components required for the locking mechanism are of very small configuration and accordingly are scarcely of great significance in terms of their inherent weight. By virtue of the integration of the latching profile 22 into the guide 3, the guide 3 itself is lightened by the introduction of a hole profile and, moreover, weight is saved because an additional latching profile does not need to be attached to the guide 3 or to the seat framework frame 1.

Claims

1. A locking mechanism for a head restraint which is at least indirectly coupled to a framework part of a seat via at least one retaining bar and can be positioned in a latching manner at various heights by means of an operating element which interacts with at least one interlocking element, in which the operating element is at least indirectly retained on a frame part of the head restraint, which frame part at least indirectly retains a cushion element.

2. A locking mechanism as claimed in claim 1, in which the operating element is formed in the manner of a push-button.

3. A locking mechanism as claimed in claim 2, in which the operating element is arranged within a trough-like hollow in the cushion element with a contour set back behind an open edge of the trough.

4. A locking mechanism as claimed in claim 2, in which the push-button is fitted onto an actuating rod which is fixedly connected to the forcetransmission element.

5. A locking mechanism as claimed in claim 2, in which the push-button is fitted on an actuating rod which is guided displaceably in the frame part and by means of which the force-transmission element can be acted upon by means of an end region opposite the pushbutton.