CA2046312A1

CA2046312A1 - Plastic wheel cap

Info

Publication number: CA2046312A1
Application number: CA 2046312
Authority: CA
Inventors: Wilfried Sommer; Ernst A. Matthei
Original assignee: Individual
Current assignee: DEVALIT VAN DEEST & CO KG GmbH
Priority date: 1989-02-22
Filing date: 1990-02-22
Publication date: 1990-08-23
Also published as: AU5267090A; EP0384459A1; DE8902099U1; WO1990009898A1

Abstract

The invention concerns an injection-moulded plastic wheel cap with a disk (1) for covering the rim cavity of an automobile rim or the like and with a fastening device (3) with radially spring-loadable snap-in projections (6) which is arranged centrally on the rear face (2) of the disk (1). To obtain a simpler, more attractive wheel cap, the snap-in projections (6) start from one front face of a sprayed-on annular wall (7) whose other front face is rooted in the disk (1) via a material bridge (8) of smaller cross-section than the annular wall (7) (rotationally symmetrical wall element).

Description

The present invention relates to a plastic wheel cover that is injection-moulded, this incorporating a disk to cover the rim groove of an automobile rim or the like, and having a attachment system that incorporates detent projections that can be sprung radially outwards and which is arranged centrally on the back of the disk.

In a known plastic wheel cover of this kind, the individual detent projections of the attachment system are moulded on so as to be free-standing on the back of the disk. In order to increase the effectiveness of the spring action, the heads of the detent projections rest on a common, exposed annular spring.
This spring is installed in a cage formed from an annular wall that is moulded on and which, at the top, becomes retaining clips that catch in the ring. The use and arrangement of such a ring spring increases production costs and, in the event of inadvertent mismatching, increases the danger that the wheel cover will be lost when the vehicle is being driven. In addition ;to this, there is an appearance problem, insofar as the radial ribs that are moulded onto the back of the disk and support the ring lead to large local accumulations of material, which causes corresponding radial shrinkage marks to show on the visible side of the disk.
. .
It is the task of the present invention to simplify the construction of a plastic wheel cover of this kind and to improve its appearance.

This task has been solved by the invention described in claim 1.

~he sub-claims describe advantageous developments of the plastic wheel cover according to the present invention.
,: .
As a result of such a configuration, it has been possible to -~arrive at a simplified structure. Additional parts, such as, ~or ~ 2 . . .

:- : ~ : .

-example, the spring discussed above, can be eliminated. The associated assembly costs have also been eliminated. Despite this, large detent forces can be applied. Specifically, this was done in that the detent projections extend as one piece from one face side of an annular wall (a rotationally symmetrical wall element), the other face side of which merges into the disk through a material bridge that is of reduced cross-section compared to the annular wall. Suitably configured, the material bridge that is reduced cross section entails the advantage that stresses do not pass into the disk so as to cause deformations, hence because of the special configuration the visi~le surface of the wheel cover is not affected by the deformation of the detent eIement; the above-discussed radial can also be eliminated so that shrinkage marks that result from these are also eliminated.
In addition, it has also been found advantageous that the material bridge is continuous in the peripheral direction.
Especially in the case of large wheel covers, this entails the advantage of a connection of the attachment system to the disk that can itself resist large mechanical forces. If, for example, a higher degree of flexibility or elasticity is to be achieved in other sizes, the measure that is then preferred can be of advantage, in that the material bridge is configured so as to be broken in the peripheral direction. What then remains, for example, are part-circular bridges in the form of ribs or rod-like sections of material. It is also an advantage that the material bridges extend from the inner side o~ the annular wall.
In order to further enhance the springiness of the detent pro~ections that begin in the annular wall, it ls proposed that there be notches with concave openings that face away from the back of the disk between the detent pro;ections. This results in a crown-like or castellated attachment system body. It has also been found to be advantageous that the annular wall diverges in a direction that faces away from the disk to form detent surfaces that are rotationally symmetrical to the normal of the annular wall. This results in a relatively long detent surface by ;: .

- ~ - :. . . .. - :: .

. - .

involving the outer surface of the annular wall. A further means of enhancing the springiness is that in the transition area between the annular wall and each detent projection there is a break in the detent projection wall. Corresponding ~reaks also help dissipate the heat generated when the vehicle is moving. In order to simplify making the snap connection, provision is made that the unattached end of each detent projection forms a detent run-up slope. A further favourable configuration is brought about by depth-limiting stops on the attachment system. These depth-limiting stops prevent the wheel cover being pressed too deeply into the wheel rim. In addition, a defined assembly (plus partial loading in the installed state) is ensured. From the constructional point of view, it is found to be advantageous that the depth-limiting stops are formed from outwardly oriented stop lugs on the detent projections. Alternatively, it has been found advantageous that the stop lugs be arranged in the notches.

The object of the present invention will be described in greater detail ~elow on the basis of the embodiment shown in the drawings appended hereto. ~hese drawings show the following:

Figure 1: a plastic wheel cap formed according to the present invention, in side view;
Figure 2: a plan view corresponding to figure 1;
Figure 3: a back view of the wheel cover;
Figure 4: a cross section on the line IV-IY in figure 3;
Figure 5: a cross section on the line V-V in figure 3, both cross sections being considerably enlarged, Figure 6: a vlew corresponding to figure 3 although with the depth-limiting stops arranged within the notches.
, A plastiç wheel cover that conceals the rim edge of an automobile wheel or the like (not shown herein) consists of a disk 1 which, on its back 2, continues to become an attachment system 3. The latter is moulded i~ place from the same materials.

.. ... ... . .
- . : . : ~
.
- .

~ , ~ , - :
: ~; . : . : ::

:~ :
.

The visible side 4 of the disk 1 slop~s down gradually to the periphery; the edge 5 is chamfered or rounded off.

The attachment system 3 is located centralIy. It forms four detent projections 6 that are spaced equidistantly apart. These projections extend from an annular wall 7 concentrically to the longitudinal mid-line axis x-x, from the face side 7' of the annular wall 7 that is remote from the back 2 of the disk 1. The annular wall 7 (rotatary wall element) can also be formed as a spherical wall element or as a paraboloid of revolution of a similar shape which leads to an almost point connection on the wheel cover disk 1, and entails the advantage that almost no bending stresses are introduced into the visible surfaces, thereby keeping the appearance of these surfaces free from any disfiguring deformations.

The other face side, which is to say, that which faces the back 2, blends into the disk 1 while leaving a material bridge 8 that is clearly of reduced cross-section. -The thickness Y of the material bridge, measured radially, is approximately equal to one-fifth to one-third of the thickness of the annular wall 7 measured in this direction, or the thickness Z
of the adjacent projections 6. The height H is essentially equal to the thickness Y. In order to avoid any shearing effects, each of these transitions is rounded so as to be concave.

In certain cases, instead of the continuous material bridge 8 discussed heretofore, it is also possible to use a configuration in which the material bridge 8 is interrupted or broken in the peripheral direction, so that the face side 7 " is connected to the disk 1 through one or a plurality of long cross-pieces or ~'points," respectively.

-:, i ~ . . : -- '-' ' ~ ~ .

As can be seen particularly plainly from figures 4 and 5, the material bridge 8 lies in the area of the inner side 7 "' of the annular wall 7. The inner wall 7'" lines up in the same plane as the corresponding inner side of the material bridge 8. The thickness of the annular wall 7 itself decreases towards the disk 1.

The annular recess that leads to the material bridge 8 that is of reduced cross-section is wedge-shaped. Its angle a is approximately 30'. The angle point is broken.

Notches that have concave openings and face away from the back 2 of the disk 1 extend between the individual detent projections 6.
The bottom of the notch defines the above-discussed face side 7' of the annular wall 7. At the unattached ends of the detent projections 6, the shape that forms the notches becomes, in each instance, a flatter curve and is comparable to a cone section.
The maximum width of the notches 9,at their openings is greater than the head width B of the detent projections 6 as measured in the peripheral directlon. This ratio is approximately 3:1.

The detent pro~ections 6 are inclined such that their feet are closer to the longitudinal midline axis x-x of the attachment system 3 than their unattached head ends. In one configuration of the attachment system 3 in the form o~ a sphere or ball, the outer side 6' is curved. In this case, the ball would be formed as a hollow ball open on the side that is remote from the d$sk and would have an indented structure similar to that in figure 1.
The same applies to a paraboloid-like form.
.
The corresponding angle [Ausstellungswinkel, for which no workable equivalent could be found. Tr.] is approximately 18- to the normal line of the annular wall.
: . ~
; ' 6 : `
.. ..... .. ,~
, ~

, ., , .-:

.: , , - -The outer side 6' of the individual detent projections 6 combined with the outer side 7 " " of the annular wall 7 that are on the same plane together form a correspondingly inclined and rotationally symmetrical detent surface for the mating detent means (not shown herein).

In order to simplify the snap-in procedure, the unattached end of each detent projection 6 forms a detent run-up slope 10. The angle of inclination is approximately 45-.

In order to increase the flexibility of the actual detent projection 6 there is a break 11 in the transition area between the annular wall 7 and each detent projection 6. This break 11 that is located in the detent projection wall is oriented radially and is circular, which is to say it is comparable to a drilled hole. In addition to increasing flexibility, combined with the notches 9 that are left between the individual detent projections 6, this provides a good path for ventilation if, with reference to the breaks 11, the surface is not covered by the mating detent means.
:
The depression 14 that extends radially and reaches as far as the centre and which can be seen on the visible side 4 (see, for example, figure 2) can display lettering, for example, indicating the nàme o~ the manufacturer. The shape, which extends through to the back can be seen from figures 3 and 6. It i5 not very high, as is shown on the left-hand side of figure 1. The shape bears the reference number 15 and extends into the cup-shape of the attachment system 3.

Depth-limiting stops 12 are arranged on the attachment system 3 used in both embodiments. These depth-limiting stops are used to prevent the wheel cover from being pressed too far into the wheel rim. In addition, they result in a defined assembly.

: ~ :

-These depth-limiting stops 12 are formed from stop lugs 13. In the first embodiment (figures 1 to 5) these extend from the outer side 6' of the detent projections 6. They extend beyond this in a radial direction by a clearly defined amount. They are moulded on such that, in each instance, on both sides of the breaks 11 there is a tab ~see figure 3). These tabs extend parallel to the plane of the disk l.

In the second embodiment (figure 6), the depth-limiting stops 12 are formed from stop lugs 13 that extend into the notches 9, i.e., extend from the bottom 7' of the notch, where they are .
moulded on; from there they extend radially outwards in a similar way and extend by the necessary amount beyond the outer side 6' of the individual detent pro;ections 6 in the same way as the stop lugs 13.

The features of the present invention disclosed in the above description, drawings, and claims can be important either singly or in combination for realizing the present invention.

, - .

~ 8 : ~ ~
~' ' . .
': ~ . : ' . .,, .' ~ . . " ' : ' '' ' , ' . .. .' ,, .. ' .' ' .. '. ' .' :

Claims

PATENT CLAIMS

1. A plastic wheel cap produced by injection moulding with a disk (1) to cover the rim edge of an automobile rim or the like, and with an attachment system (3), that incorporates detent projections (6) that can be sprung radially outwards and which is arranged centrally on the back (2) of the disk (1), characterized in that the detent projections (6) extend from one face side (7') of an annular wall (7) that is moulded in place, of which the other face side (7'') merges into the disk (1) through a material bridge (8) of reduced cross section of the annular wall (7) (rotationally symmetrical wall element).

2. A plastic wheel cover, in particular as defined in claim 1, characterized in that the material bridge (8) is configured so as to be continuous in the peripheral direction.

3. A plastic wheel cover, in particular as defined in one or more of the preceding claims, characterized in that the material bridge (8) is broken in the peripheral direction.

4. A plastic wheel cover, in particular as defined in one or more of the preceding claims, characterized in that the material bridge (8) extends from the inner side (7''') of the annular wall (7).

5. A plastic wheel cover, in particular as defined in one or more of the preceding claims, characterized in that between the detent projections (6) there are notches (9) with concave openings that are remote from the back (2) of the disk (1).

6. A plastic wheel cover, in particular as defined in one or more of the preceding claims, characterized in that the annular wall (7) diverges in the direction that faces away from the disk (1) to form detent surfaces that are rotationally symmetrical with the normal line of the annular wall (longitudinal midline axis x-x).

7. A plastic wheel cover, in particular as defined in one or more of the preceding claims, characterized in that within the transition area between the annular wall (7) and each detent projection (6) there is a break (11) in the detent projection wall.

8. A plastic wheel cover, in particular as defined in one or more of the preceding claims, characterized in that the unattached end of each detent projection (6) forms a detent run-up slope (10).

9. A plastic wheel cover, in particular as defined in one or more of the preceding claims, characterized by depth-limiting stops (12) on the attachment system (3).

10. A plastic wheel cover, in particular as defined in one or more of the preceding claims, characterized in that the depth-limiting stops (12) are formed from outwardly oriented stop lugs (13) on the detent projections (6).

11. A plastic wheel cover, in particular as defined in one or more of the preceding claims, characterized in that the stop lugs (13) are arranged in the notches (9).