FORM 2
THE PATENT ACT 197 0 (39 of 1970)
The Patents Rules, 2003 COMPLETE SPECIFICATION See Section 10, and rule 13)
TITLE OF INVENTION PLASTIC PENDULUM SUPPORT

APPLICANT(S)
a) Name
b) Nationality
c) Address

ZF FRIEDRICHSHAFEN AG
GERMAN Company
88038 FRIEDRICHSHAFEN
GERMANY

3.

PREAMBLE TO THE DESCRIPTION

The following specification particularly describes the invention and the manner in which it is to be performed : -


The invention relates to a plastic pendulum support with a rod-shaped base body and receiving elements arranged at the free ends of the base body for the ball heads of ball pins.
Plastic pendulum supports of this kind are used, inter alia, in motor vehicle manufacture, where it has generally proved successful to form the pendulum supports from plastics material. The material which is used offers significant advantages, in particular with regard to the connection between the receiving elements and the ball heads, as the ball heads can be snapped directly into the receiving elements, which are formed as corresponding ball sockets, on account of the elastic properties of the plastics material. The process of assembling the components which are to be connected together is as a result significantly simplified while keeping assembly costs comparatively low.
However the use of the plastics material has the disadvantage of the elasticity which on the one hand is necessary for the assembly process described above on the other hand requiring an E modulus which is substantially lower when compared with other materials, in particular metal, so that the absorption of forces and, here in particular, of buckling loads is considerably reduced when compared with metal materials. The low load limit can within certain limits in the first place be compensated by increasing the cross-sectional dimensions, while there is additionally the possibility of increasing the areal moment of inertia and therefore the load-bearing capacity of the overall construction through a special cross-sectional form.
Special cross-sectional forms for the pendulum supports described according to the preamble are known in this connection from DE 25 39 698 Al, for example. A construction called a torsion bar linkage is described in this publication, this consisting of a connecting rod of plastics material with ball sockets of the same plastics material integrally formed on at its two ends, and wherein ball pins are locked into the ball sockets in a sealed manner. The torsion bar linkage consists as a

whole of polyurethane, the connecting rod having an H-shaped cross section with a relatively thin web and thin flanges.
In addition, US 5,352,059 discloses that the base body according to the preamble can have a plurality of webs which are arranged side by side and are connected together by means of a connecting web which is arranged approximately centrally. When compared with the embodiment which is known from the first-mentioned publication, an arrangement of this kind has an areal moment of inertia which is increased by approximately 30%, with the same construction space boundary (outer circle of the cross sections as reference magnitude) in each case being used for the calculation.
The cross sections known until now are entirely sufficient for numerous applications and the resultant loads, however the technical solutions which are known from the prior art have limitations where special requirements with increased load values and limited construction space dimensions are concerned.
The object of the invention is therefore to form a plastic pendulum support of the type according to the preamble so that, in contrast to known solutions, it has an areal moment of inertia which is increased once more, so that the pendulum supports of a novel formation can also be used in areas where metallic materials were previously employed as pendulum support material. Furthermore, the form of the pendulum support is to make a simple production process possible, as particularly the tube cross sections predetermined for an optimal areal moment of inertia in the case of plastics materials can only be produced by means of complex methods, such as extrusion blow moulding, a fusible core, gas injection or water injection technique.
This object is achieved according to the invention in that the cross section of the base body of the plastic pendulum support has a substantially S-shaped cross section with at least three transverse webs arranged at a parallel spacing from one another

and connecting webs in each case coupling two adjacent transverse webs, the connecting webs being arranged at opposite end regions of the transverse webs.
The described feature combination enables the areal moment of inertia to be increased once more by more than one third with respect to the form known from the above-mentioned US publication US 5,352,059, with the same outer circle diameter being taken as a basis for the calculation. Moreover, the S-shaped cross section of the plastic pendulum support can be shaped with simple tools, so that the subject matter of the invention has low production costs and only takes up a small construction space in relation to the loads which are to be absorbed.
Special forms of the subject matter of the invention are additionally comprised in the subclaims referring back to the main claim.
It has proved particularly advantageous to round the edges of the outer transverse webs of the S-shaped cross section which point towards the outside. In this respect the edge roundings reduce the necessary construction space, although do not have a significant negative influence on the calculated areal moment of inertia.
It may in addition be expedient for the thickness of the transverse webs and the spacing dimension of two adjacent transverse webs to have substantially equal values. This feature leads to a corresponding optimisation of the load values which are to be absorbed. In this connection it is additionally to be emphasised that a uniform wall thickness of the cross section is accompanied by uniform shrinkage of the component which is produced in the injection moulding process, so that stresses in the component are prevented.
Furthermore, according to one appropriate development of the subject matter of the invention, the connecting webs are arranged in at least two sub-regions at opposite lateral surfaces in the axial longitudinal direction of the rod-shaped base body. Any

particular stresses of the overall component can be better absorbed through this feature combination.
Provided that sufficient construction space is available, it may in addition be of advantage to arrange reinforcement ribs extending in the direction of the longitudinal axis of the base body at the outer boundary surfaces of the outer transverse webs at least in the central region of the base body, which additionally increases the load limit of the overall construction.
The material PA 6.6 GF 30, inter alia, has proved to be a particularly advantageous material for forming the plastic pendulum support, as this provides an optimal compromise between the necessary elasticity values for clipping the ball heads into the ball sockets of the receiving elements and at the same time an adequate E modulus for the load values which are to be absorbed. Plastics materials without glass fibre reinforcement can of course also be used.
An embodiment of the subject matter of the invention is illustrated in detail in the following on the basis of the accompanying drawings, in which:
Figure 1 is a side view of the plastic pendulum support according to the
invention,
Figure 2 is a representation of the cross section A-A from Figure 1 and
Figure 3 is a representation of the cross section B-B from Figure 1.
The plastic pendulum support represented in its totality consists of a base body 1 as well as two receiving elements 2 and 3 fixed integrally to the free ends of the base body 1. The receiving elements are provided for the introduction of the ball heads of ball pins, which are not represented at this point. Recesses 4 in the form of ball

sockets are formed inside the receiving elements 2 and 3 for receiving the ball heads. The entire pendulum support is made of PA 6.6 GF 30.
It is obvious from Figures 2 and 3 that the base body 1 of the plastic pendulum support has a substantially S-shaped cross section. The S-shaped cross section is composed of three transverse webs 5, 6, 7 which are arranged at a parallel spacing from one another, with two adjacent transverse webs in each case being coupled together by a connecting web 8 and 9, respectively. Here the connecting webs 8 and 9 are disposed at opposite end regions of the transverse webs. The form of the cross sections in Figures 2 and 3 is substantially identical, the difference consisting solely in the fact that in Figure 3 the cross section is turned through 180°, so that, viewed from the side, the interspace 10 originally present in Figure 2 and the interspace 11 are arranged on the opposite side with respect to Figure 2.
The distribution of the cross-sectional formations of Figure 2 and Figure 3 is represented by way of example in Figure 1, where a cross-sectional form according to Figure 2 was in each case selected in the outer end regions, whereas a cross-sectional form according to Figure 3 was selected in the inner region of the base body.
It is additionally obvious from Figures 2 and 3 that the edges of the outer transverse webs 5 and 7 of the overall S-shaped cross section which are directed towards the outside have roundings 12.
It can in addition be seen from the figures that reinforcement ribs 13 are arranged at the outer surfaces of the outer webs 5 and 7 in the centre of the base body 1.
Due to the form, which overall is novel, of the cross section of the described plastic pendulum support, apart from the low production costs, the areal moment of inertia, once more increased with respect to the solutions known from the prior art, is in particular to be considered as positive. In this respect the invention is not restricted

to the selected size of the form, with respect to which it is to be noted that the thickness of the transverse webs and the spacing dimension of two adjacent transverse webs have equal values in the represented embodiment.
These additional features of form can of course be varied in other constructional variants.

List of reference numbers

1 base body
2 receiving element
3 receiving element
4 recess
5 transverse web
6 transverse web
7 transverse web
8 connecting web
9 connecting web
10 interspace
11 interspace
12 rounding
13 reinforcement rib
14 sub-region

CLAIM:
1. Plastic pendulum support with a rod-shaped base body (1) and receiving
elements (2, 3) arranged at the free ends of the base body (1) for the ball heads
of ball pins,
characterised in that
the cross section of the base body (1) has a substantially S-shaped form with at least three transverse webs (5, 6, 7) arranged at a parallel spacing from one another and connecting webs (8, 9) in each case coupling two adjacent transverse webs (5, 6, 7), wherein the connecting webs (8, 9) are arranged at opposite end regions of the transverse webs (5,6, 7).
2. Plastic pendulum support according to Claim 1,
characterised in that
the edges of the outer transverse webs (5, 7) of the S-shaped cross section which are directed towards the outside have roundings (12).
3. Plastic pendulum support according to either of Claims 1 and 2,
characterised in that
the thickness of the transverse webs (5, 6, 7) and the spacing dimension of two adjacent transverse webs (5, 6,7) have substantially equal values.
4. Plastic pendulum support according to any one of Claims 1 to 3,
characterised in that

the arrangement of the connecting webs (8, 9) is arranged in at least two sub-regions (14) at opposite lateral surfaces in the axial longitudinal direction of the rod-shaped base body (1).
5. Plastic pendulum support according to Claim 4,
characterised in that
two sub-regions (14) are in each case disposed in a different connecting web arrangement at the lateral surfaces of the base body (1).
6. Plastic pendulum support according to any one of Qaims 1 to 5,
characterised in that
reinforcement ribs (13) extending in the direction of the longitudinal axis of the base body (1) are arranged at the outer boundary surfaces of the outer transverse webs (5, 7) at least in the central region of the base body (1).
7. Plastic pendulum support according to any one of Claims 1 to 6,
characterised in that
the base body (1) and the receiving elements (2,3) are made of PA 6.6.