Light alloy rim with a front covering element in stainless steel

Abstract: This invention concerns a light alloy rim for car wheels, consisting of a hub with a centre hole and an external border or ring, which ends in a boundary edge. The rim is furnished with a covering element (6, 14) in stainless steel on at least one part of the front surface of the rim, this covering element (6, 14) being fixed in place by mechanically upsetting or chamfering it to at least one part of the rim.

Description: Field of the invention This invention concerns the field of light alloy rims for car wheels as defined by the features of the preamble of claim 1. . State of the art There already exist covering elements for light alloy rims for car wheels in a different material, such as stainless steel. These elements are generally limited to the outer area of a rim and are fastened to the rim by means of additional fixtures, which are awkward and liable to work loose, with the risk that the cover will become detached as a result of contact with a pavement or similar, as may easily happen during a parking manoeuvre. For example, the generic document US 4 530 542 discloses a wheel center having an outboard side to which a steel cover is attached. The cover has outer and inner axial flanges which are a press fit onto corresponding shoulders of the wheel center. However, in order to secure the cover in place even during some vehicle operating conditions, additional locking means, such as adhesive and/or screw-threaded nuts, securing the wheel assembly to the vehicle axle hub and bearing against the outboard surface of the cover, are necessarily used. Purpose and explanation of the invention One of the aims of this invention is to propose and produce a light alloy rim equipped with a covering front element in stainless steel, fixed in place with an innovative mechanical means, without the use of glue or other additional means, but, nevertheless, held there permanently and securely. Another purpose of this invention is to supply a light alloy rim with a covering element that covers the whole front part, from the outer edge to the centre hub. A further aim of the invention is to supply a light alloy rim with a circular covering element that covers an outer ring of the rim itself. These aims are achieved by the features of claim 1. The covering element may extend from the outer edge as far as the centre hub of the rim, or be restricted to the most external border or ring of the front of the wheel. In any case, the external seaming line of the element is hidden, invisible from the front of the rim. Brief description of the drawings The enclosed drawings illustrate examples of the light alloy rim with a covering element applied, in accordance with the invention. In said drawings: Fig. 1 shows a cross-section of a light alloy rim with a complete front covering; Fig. 2 shows a similar section of a light alloy rim with a covering only on the external border or ring; Fig. 3 shows, in cross-section, an enlarged detail of the covering in Fig. 2, in correspondence with the centre hole in the rim hub; Fig. 4 also shows a cross-section of an enlarged detail of the part of the rim border circled in Figs 1 and 2; and Fig. 5 shows an example of the equipment for applying the covering element to the rim border. Detailed description of the invention Generally speaking, the light alloy rim 1 to which this invention can be applied is of the conventional type, with spokes and holes of any aesthetic shape around a central hub 2 and with an external border or ring 3 which projects frontally and ends in an outer edge 4. The hub will have a centre hole 5 and holes 5' for the fixing screws that hold the rim on the car wheel support. The rim may be completely covered in the front part - Figs 1 - 3. In this case, a sheet of stainless steel 6 will be needed, suitably shaped in such a way as to match the visible front surface of the rim, covering it completely. The sheet will also have folded-back parts which will interact with the corresponding parts on the rim. In detail and referring to Fig. 3, the centre hole 5 in the hub has a circular protuberance 7 that defines an undercut 7' which interlocks with a turn-up 8 on the internal edge of the steel sheet 6. Similarly, with reference to Fig. 4, the outer external edge 4 of the rim has an undercut 4' to which is hooked an external turn-up 9 of the steel sheet 6. In this way, the stainless steel sheet 5 is completely and securely fastened to the rim 1, totally covering it. In accordance with the invention, the rim 11 may also be only partially covered in front with a stainless steel element, as shown in Fig. 2, at the level of the visible surface of the edge or ring 12. In such a case, this edge or ring surface 12 is finished and covered with a circular strip 14 in stainless steel, extending over the outer edge 13 and fastened to it. The external margin 15 of the strip 14 is folded behind an undercut 16, made around the edge 13. Said undercut 16 may consist of a rim gutter, as shown in the drawing - Figs 2 and 4 - or by a shoulder or step, turned over towards the rear of the edge. The covering strip 14 may be applied to the rim with a piece of equipment 17, such as that shown in Fig. 5, for example. This equipment consists of various functional devices 17, 18, designed to hold the circular strip 14 to the internal surface of the edge or ring 12 of the rim, to turn up an outer part of the strip so that it grips the outer edge 13 and to fold over, by either the mechanical means of upsetting or chamfering, the external margin of the strip 14 behind the undercut 16, that is, into the rim gutter around the edge. As a result, the covering strip in stainless steel will be tightly and securely fastened to the rim, covering the surfaces in question. The upset or chamfered margin 15, acting with the undercut or rim gutter, guarantees the solidity and stability required for the covering strip, producing the desired effect.

Claims: Light alloy rim (1) for car wheels, consisting of a hub (2) with centre hole (5) and external border or ring (3; 12) that ends in an outer edge (4; 13), and a covering element (6, 14) in stainless steel on at least one part of the front surface of the rim, characterised in that said rim is provided with at least a circular undercut (4'; 16) made around said outer edge and in that said covering element has at least an external margin (9; 15) folded back behind said undercut by means of upsetting or chamfering so that said covering element is mechanically fixed to the rim. Light alloy rim according to claim 1, wherein said undercut consists of either a rim gutter, a shoulder or step turned back towards the rear. Light alloy rim according to any one of the previous claims, wherein said covering element (6) in stainless steel consists of a sheet that extends all over the front surface of the rim, from the hole in the hub to the edge of the external ring, said covering element having, at one side, a turn-up (8) for gripping an undercut (7, 7') located in the centre hole of the hub and, at the other, a peripheral turn-up (9) that interacts with the circular undercut (4') located around the edge (4) of the boundary ring of the rim. Light alloy rim according to any one of the previous claims, wherein said covering element (14) in stainless steel consists of a circular strip which adheres to and covers just the visible surface of the border or ring (12), and which is turned up over said outer edge (13) in such a way that the outer margin (15) is folded behind the circular undercut (16) located around the edge itself. Light alloy rim according to any one of the previous claims, wherein said covering element covers at least one part of the front surface and the outer front edge without interruption and with a seaming line at the outer undercut which is invisible from the front of the rim.

Inventors: TANGHETTI PAOLO, TANGHETTI, PAOLO
Applicants: TECNOFORMING S P A, TECNOFORMING S.P.A.
Application year: 2000
Main classification: B60B7
IPC codes: B60B7