GB1560234A

GB1560234A - Fastening of the push-and twist type

Info

Publication number: GB1560234A
Application number: GB4475/77A
Authority: GB
Original assignee: Gebrueder Happich GmbH
Current assignee: Johnson Controls Interiors GmbH and Co KG
Priority date: 1976-05-26
Filing date: 1977-02-03
Publication date: 1980-01-30
Also published as: FR2361245B2; FR2361245A2

Description

(54) FASTENING OF THE 'PUSH-AND TWIST' TYPE (71) We, GET RUDDER HAPPICH G.M.B.H., a German Body Corporate, of Neuenteich 62/76, 56 Wuppertal-Elberfeld, German Federal Republic, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a fastening of the "push-and-twist" type. Such a fastening is defined in this Specification as a fastening comprising two parts, one such part, called in this Specification a "key part" having a stem formed with a "beard configuration", i.e. one or more barbs, jags, or like projections, and the other such part, called in this specification a "keyhole part", having a non-circular opening, called in this Specification a "keyhole".

The shape and size of the keyhole is such that the beard configuration of the key part can only pass through the keyhole when the or each projection of the beard configuration is aligned with a wide part of the keyhold, such as radial slot. In use of the fastening, the key part is suitably aligned with the keyhole, and the beard configuration is then inserted through the keyhole. The key part is then turned to a fastening position in which the (or each) projection of the beard configuration is aligned with a narrower portion of the keyhole. In this position, the beard configuration extends beyond the periphery of the keyhole and thus prevents the key part from being withdrawn through the keyhole.

It will be understood that the key part and the keyhole part are movable relative to one another, so that where in this Specification mention is made of the position of the key part, or of moving the key part (e.g. "inserting the key part", or turning the key part") the description is intended to cover not only the case where the key part is moved, but also the case where the key part is stationary and the keyhole part moves to effect the fastening.

The invention specifically relates to a push-and-twist fastening of the kind (herein referred to as a fastening of the kind described) in which the key part and the keyhole part each has co-operating means to take up axial play between the key part and the keyhole part as the key part is rotated to fasten it, the co-operating means comprising a ramp structure on one of the two parts of the fastener, and a bearing surface on the other part of the fastener which is to bear against the ramp structure to tighten the fastener as the key part is rotated towards its fastened position. This tends to prevent unintentional rotation of the key part from its fastening position to a releasing position.

Examples of push-and-twist fastenings are described in our co-pending Patent Application No. 6375/75 (Serial No.

1,488,097), where the fastening is used to fasten a vehicle fitting, such as a hand grip or arm rest, to a vehicle body panel. The examples described in our above mentioned Application each have a key part, the beard configuration of which comprises two projections, and a keyhole part which has a keyhole with a central circular part with a pair of radial slots extending outwardly from the central circular part to form a wider part of the keyhole through which the beard configuration is to pass.

In each of the arrangements described in our earlier Application, the ramp structure comprises a pair of ramps formed on the rear face of keyhole part, and the projections of the beard configuration ride up the ramps to tighten the fastening as the key part is turned to its fastening position.

The ramps are disposed immediately adjacent the edge of the keyhole.

During research on fastenings of the construction described in our earlier Application it was found by experiment that some features of the fastening may be unsatisfactory when the stresses are high. For example, during the manufacture of the inner panel of a vehicle door or vehicle body, it is not always easy to cast the ramps during the operation (necessarily a single one) which includes moulding, embossing und perforation. The reason is that the working life of the deformation insert is shorter than that of the other tool inserts. Furthermore, the projections and ramps abut one another only over a small surface area, so that if they are subjected to relatively strong pull-out forces, material may yield and the fastening may become loosened. Furthermore, improvements can be made in the centring, i.e. the manner of preventing radial play. If the stem of the key part has a flat or nonround cross-section where it passes through the keyhole, it is not centred in all directions. Even if the stem has a round shape corresponding to the central circular part of the keyhole, permanent centring is not guarenteed, since the edges owt the keyhole (which may be sharp) may deform or cut the stem of the key part as a result of many stresses on the hand grip or other fastened part, so that after a time it is not firmly secured radially of the stem of the key part.

An aim of the present invention is to provide a fastening for a hand grip, arm rest or other fitting, which fastening is of the push-and-twist type, can be manufactured relatively cheaply and easily, and is robust, so that even if subjected to relatively strong forces during its entire working life, the fastening does not become loose either radially or axially.

With this aim in view, the invention is directed to a fastening of the "push-andtwist" type (as defined herein) and of the kind described, in which the means to take up axial play which is formed on the "key part" (as defined herein) is formed on a flange or like solid member carried by the stem of the key part and axially spaced from the "beard configuration" (as defined herein), and in which the said means is so positioned that its surface which engages the co-operating means to take up axial play on the "keyhole part" is disposed at a region or regions spaced from the edge of the "keyhole" of the "keyhole part" (as defined herein), one of the co-operating means to take up axial play comprising projections which are positioned so as to fit into corresponding arcuate recesses which form the other co-operating means, the arcuate recesses being shallower at one region than at another region so that the bases of the recesses form ramps of the ramp structure along which the projections ride towards the shallower region during turning of the key part to its fastening position.

As a result of the engaging regions being moved away from the edge of the keyhole, the fastening is easier to manufacture. In particular, the machine tool is of simpler construction than the prior art tool, and therefore lasts longer. In contrast to the prior art, the play take-up means on the keyhole part does not merge into the free edge of the keyhole, but is instead carried on a flange face or the like.

Thus, the mutually abutting bearing surfaces of the two co-operating means can have a relatively large area, so as to provide high bearing forces without any difficulty. A further advantage is that the arrangement provides for automatic centring, and no other centring means are essential.

In cases where tolerances or differences in the thickness of structural elements have to be allowed for, the ramp structure can be resilient and can be arranged to be compressed in a direction parallel to the axial direction of the stem of the key part.

Several exemplary embodiments of a fastening according to the invention are shown in simplified form in the accompanying drawings, in which: Figure 1 shows an end part of a hand grip, arm rest, or like vehicle fitting, such fitting carrying the key part of a fastening according to the invention Figure 2 shows a body wall with a keyhole forming a keyhole part of the fastening; Figure 3 shows in longitudinal section, the fastening of Figures 1 and 2, with the key part inserted in the keyhole, but not turned; Figure 4 shows the fastening of Figure 3 after the key part has been turned, and Figures 5 and 6 are views similar to Figures 1 and 2 but showing another embodiment of a fastening according to the invention.

Figures 1--4 show a fastening 2, which comprises a key part 3 and a keyhole part 9.

The key part 3 is formed on the projecting end of a rigid reinforcing insert 14 which can form a frame for a hand grip or arm rest.

The key part 3 has a frusto-conical stem formed with projections forming a beard configuration 6.

At the end region of insert 14 is formed a moulded structural member 15. This member 15 includes a bearing flange 16 axially spaced from the beard configuration 6 and formed with recesses 17, as shown more clearly in Figures 3 and 4. The central conical stem 18 is integral with the flange 16, and projects beyond the beard configuration 6.

The keyhole part 9, shown in Figure 2, comprises a keyhole 7 formed in a body wall 5 and having substantially the same shape as a cross-section of the stem 18 taken through beard configuration. Since, in this example, flange 16 has arcuate recesses 17, body wall 5 has corresponding projections 19, which are positioned so as to fit into corresponding recesses 17 after the key member has been inserted in the keyhole and turned.

One end region of each arcuate recess 17, i.e. the end region which will be adjacent a projection 19 when the key part is first inserted through the keyhole is deeper than the other end region of the recess in which the projection 19 will lie after turning of the key part. Thus, each recess forms a ramp extending almost to the main face of flange 16, resulting in a tightening effect during the turning of the key part as explained below.

Since recesses 17 and projections 19 not only fit together but are spaced at the same distance (radius) from the centre of the keyhole, the fastening part 3 is very effectively centred with respect to the fastening part 9. Consequently, it is not necessary for the conical stem 18 to have dimensions exactly corresponding to the keyhole 7. In this example, stem 18 serves to stabilize the beard configuration, and also provides for rapid position-finding, i.e., prepositioning, for lining up the key part 3 at the beginning of assembly, thus advantageously speeding up the process of assembling a hand grip or arm rest.

The manner in which the fastening is made secure is clear from Figures 3 and 4.

Figure 3 shows the position in which the key part has been inserted, but not turned, so that the projections 19 lie in the deepest part of recesses 17. Rotation (i.e., turning of the key part through approximately 450 in the example) gives the position represented in Figure 4, where the projections 19 are in a less deep part of recesses 17, so that the operative edges of the beard configuration 6 abut the rear surface of the body wall 5.

In the embodiment in Figures 5 and 6, the flange on the key part carries spring bridges 1 9a pressed out of the flange. This feature may be advantageous in compensating tolerances or differences between the thickness of structural elements. The spring bridges 1 9a are projections serving the same purpose as projections 19 (Figure 2).

Projections 1 9a fit into recesses (not shown which are like recesses 17 and are formed in wall 5 of keyhole 7a.

When the key part is rotated to its fastening position ramp surfaces formed on the bases of the recesses co-operate with spring bridges 19a to progressively tighten the fastening.

WHAT WE CLAIM IS: 1. A fastening of the "push-and-twist" type (as defined herein) and of the kind described, in which the means to take up axial play which is formed on the "key part" (as defined herein) is formed on a flange or like solid member carried by the stem of the key part and axially spaced from the "beard configuration" (as defined herein), and in which the said means is so positioned that its surface which engages the co-operating means to take up axial play on the "keyhole part" is disposed at a region or regions spaced from the edge of the "keyhole" of the "keyhole part" (as defined herein), one of the co-operating means to take up axial play comprising projections which are positioned so as to fit into corresponding arcuate recesses which form the other cooperating means, the arcuate recesses being shallower at one region than at another 1 =gion so that the bases of the recesses form ramps of the ramp structure along the projections ride towards Ihe shallower region during turning of the key part to its fastening position.

2. A fastening according to claim 1, in which the recesses are formed in the flange or like solid member, and in which the projections which ride along said recesses during turning of the key part are formed on the keyhole part of the fastening.

3. A fastening according to claim 1, in which the projections are resilient and are arranged to be compressed in a direction parallel to the axial direction of the stem of the key part.

4. A fastening according to claim 3, in which the projections comprise a plurality of spring bridges formed on the flange.

5. A fastening according to any preceding claim, in which the stem portion of the key part which projects from the flange or like solid member is frusto-conical, and in which the free and of the stem projects beyond the "beard configuration" (as defined herein).

6. A fastening substantially as described herein with reference to Figures 1 to 4, or Figures 5 and 6 of the accompanying drawings.

7. A vehicle fitting fastened to a vehicle door panel or body panel by a fastening according to any preceding claim.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. One end region of each arcuate recess 17, i.e. the end region which will be adjacent a projection 19 when the key part is first inserted through the keyhole is deeper than the other end region of the recess in which the projection 19 will lie after turning of the key part. Thus, each recess forms a ramp extending almost to the main face of flange 16, resulting in a tightening effect during the turning of the key part as explained below. Since recesses 17 and projections 19 not only fit together but are spaced at the same distance (radius) from the centre of the keyhole, the fastening part 3 is very effectively centred with respect to the fastening part 9. Consequently, it is not necessary for the conical stem 18 to have dimensions exactly corresponding to the keyhole 7. In this example, stem 18 serves to stabilize the beard configuration, and also provides for rapid position-finding, i.e., prepositioning, for lining up the key part 3 at the beginning of assembly, thus advantageously speeding up the process of assembling a hand grip or arm rest. The manner in which the fastening is made secure is clear from Figures 3 and 4. Figure 3 shows the position in which the key part has been inserted, but not turned, so that the projections 19 lie in the deepest part of recesses 17. Rotation (i.e., turning of the key part through approximately 450 in the example) gives the position represented in Figure 4, where the projections 19 are in a less deep part of recesses 17, so that the operative edges of the beard configuration 6 abut the rear surface of the body wall 5. In the embodiment in Figures 5 and 6, the flange on the key part carries spring bridges 1 9a pressed out of the flange. This feature may be advantageous in compensating tolerances or differences between the thickness of structural elements. The spring bridges 1 9a are projections serving the same purpose as projections 19 (Figure 2). Projections 1 9a fit into recesses (not shown which are like recesses 17 and are formed in wall 5 of keyhole 7a. When the key part is rotated to its fastening position ramp surfaces formed on the bases of the recesses co-operate with spring bridges 19a to progressively tighten the fastening. WHAT WE CLAIM IS:

1. A fastening of the "push-and-twist" type (as defined herein) and of the kind described, in which the means to take up axial play which is formed on the "key part" (as defined herein) is formed on a flange or like solid member carried by the stem of the key part and axially spaced from the "beard configuration" (as defined herein), and in which the said means is so positioned that its surface which engages the co-operating means to take up axial play on the "keyhole part" is disposed at a region or regions spaced from the edge of the "keyhole" of the "keyhole part" (as defined herein), one of the co-operating means to take up axial play comprising projections which are positioned so as to fit into corresponding arcuate recesses which form the other cooperating means, the arcuate recesses being shallower at one region than at another 1 =gion so that the bases of the recesses form ramps of the ramp structure along the projections ride towards Ihe shallower region during turning of the key part to its fastening position.