WO1993008940A1

WO1993008940A1 - Repairing damaged light-metal rims

Info

Publication number: WO1993008940A1
Application number: PCT/NL1992/000192
Authority: WO
Inventors: Johan Van Eeken
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-10-28
Filing date: 1992-10-27
Publication date: 1993-05-13
Anticipated expiration: 1994-04-28
Also published as: NL190866B; AU2957492A; NL190866C; NL9101805A

Abstract

Method for restoring a plastically deformed light-metal rim to the original shape, which method comprises the steps of: (1) providing a plastically deformed light-metal rim; (2) heating the rim to a first temperature in the range of 80-140 °C; (3) subsequently heating the rim locally in the zone of a deformation for repair to a second temperature in the range of 200-300 °C; (4) exerting a pressure force on the rim in the zone of the deformation for repair counter to the direction of the plastic deformation present such that the zone of the deformation is subjected to an oppositely oriented deformation which is an amount the size of the elastic deformation greater than the plastic deformation for repair.

Description

Repairing damaged light-metal rims

The invention relates to repairing of damaged light-metal rims, in particular aluminium rims for cars and motor-bikes. Such rims consist of cast aluminium.

The object of the invention is to provide a method and a device which makes it possible to restore damaged, that is plastically deformed, rims to their former shape and thus make them suitable for re-use.

To this end the invention provides a method for restoring a plastically deformed light-metal rim to the original shape, which method comprises the steps of:

(1) providing a plastically deformed light-metal rim;

(2) heating the rim to a first temperature in the range of 80-140°C;

(3) subsequently heating the rim locally in the zone of a deformation for repair to a second temperature in the range of 200-300°C;

(4) exerting a pressure force on the rim in the zone of the deformation for repair counter to the direction of the plastic deformation present such that the zone of the deformation is subjected to an oppositely oriented deformation which is an amount the size of the elastic deformation greater than the plastic deformation for repair.

Due to the pre-heating a better distribution of the additional internal stresses takes place and crack formation is prevented.

The first temperature preferably lies in the range of roughly 100-120°C. The second temperature preferably lies in the range of roughly 230-260°C.

The invention also provides a device for performing the above specified method. This device comprises first heating means for heating the rim to a temperature in the range of 80-140°C; second heating means for locally heating the rim to a temperature in the range of 200-300°C; pressure means for applying a local pressure force on a zone of a rim for treating.

The manner in which the method according to the invention has to be performed , and therewith the configuration of the pressure means and their position in relation to the rim are strongly dependent on the nature of the deformation for repair. The pressure means can for instance be adapted for pressing outward the more or less cylindrical peripheral wall that has been pressed inward. In this case the device preferably has the feature that the pressure means comprise a pressure cylinder bearing on its one end a pressure distribution plate, whereof the radius of curvature corresponds with the radius of curvature of the relevant portion of the inner surface of the rim, and bearing on its other end a pressure plate whereof the radius of curvature is smaller than the radius of curvature of the original shape of the zone for treating, this such that in the operating situation the pressure means extend in the diagonal direction of the rim and can push off against this rim.

For the sake of safety this embodiment is preferably characterized by locking means blocking the axial movement of the pressure means.

To correct other deformations which cannot be treated with the above described embodiment of the invention, the device may be characterized by a frame with positioning means for fixedly positioning a rim relative to that frame, which frame also bears the pressure means; such that the pressure means can press between the frame and the rim. The pressure means can for instance exert a more or less axially directed pressure force on the rim edge or a force extending in a direction intermediate the radial direction and axial direction.

Many types of rims are commercially available, but they can be divided into a number of diameter categories. The device according to the invention can in principle accommodate for repair any desired type provided the device has the feature that the positioning means comprise a supporting member _r the inner surface of which has at least two arcuate steps with different radii of curvature for supporting rims with correspondingly differing diameters. The supporting member may for instance consist of two supporting elements, each with the form of a part of a ring, the mutual position of which can be varied. In this manner a rim can be placed easily on the supporting member.

In a practical embodiment the device has the feature that the first heating means comprise an oven.

A very practical embodiment of the required local temperature increase is obtained with an embodiment in which the second heating means comprise a burner.

It will be apparent that an oven suitable for the pre-heating step can comprise a thermostatic control.

The invention will now be elucidated with reference to the annexed drawing. In the drawing: figures 1A, B, C, D show highly schematically an embodiment of the method according to the invention; figure 2 shows a partly broken away perspective view of a_^device according to the invention in the first phase of mechanical treatment in accordance with figure ID; figure 3 is a perspective partly broken away view of a second phase; figure 4 shows a detail in partly broken away perspective view of a third phase; figure 5 shows a detail in perspective view of a fourth phase; and figure 6 shows a device according to the invention which is suitable for correcting axial deformations of the edge of a rim. Figure 1 shows in very schematic manner a rim 1 which, for instance due to an accident, has a deformed zone 2 that has been pressed inward.

The rim 1 is placed in accordance with figure IB in an oven 3 with a heating element 4, whereafter the temperature inside oven 3 is brought to a value Tl. In this embodiment the relevant temperature is approximately 120°. After a time the rim has assumed the temperature of 120°C. It is then removed from the oven, placed on positioning means to be described^"hereinafter on a frame and, as shown schematically in figure lC, heated locally by a burner 5. The flame of this burner is directed onto the deformation 2 until at this location the rim reaches the desired temperature of for instance roughly 240° (T2) . Use is made for this purpose of a suitable temperature meter. After these temperature treatments the heated rim 1 is subjected to a treatment by a pressure cylinder 6. This comprises a plate 7 distributing pressure forces and on the other side a pressure plate 8. The pressure force-distributing plate 7 has the same radius of curvature as the inner side of the rim 1. The plate 8 has a slightly smaller radius of curvature. By energizing the pressure cylinder 6 from a pressure source (not drawn) with a pressure P a pressure force designated with 9 is exerted between the plates 7 and 8 whereby the deformation 2 is pressed outward to the original shape as designated with 2* .

Figure 2 shows this treatment according to figure ID in more detail. The pressure cylinder 6 is supported by the rim 1 through cross beams 10, 11. In order to prevent the pressure cylinder 6 with accessories unintentionally springing loose, use is made for safety purposes of two locking beams 12, 13 which are connected to a work-table 14 by means of bolts 15. By tightening the nuts 16 the- rim is clamped fixedly onto work-table 14. Pressure cylinder 6 is situated beneath locking beams 12, 13 and there is therefore no danger of the pressure cylinder 6 springing loose when under pressure.

Figure 3 shows a device 17 with a frame 18 pivotally supporting a pressure cylinder 19. This can push off on one side against the frame 18 and on the other side against the inside of the rim 1 via a pressure member 20. Otherwise than with the pressure cylinder 6 according to figure 2, the angle at which the pressure force is exerted on the rim 1 can be varied by varying the vertical position of a bearing arm 21. The arm 21 is guided vertically up and downward for this purpose around a column 22 forming part of frame 8 by means of a carriage 23. This can be locked in any desired position by locking means 24.

The rim is supported on the side of the column 22 by a correspondingly shaped support block 25. Figure 4 shows a pressure member 26. Highly localized pressure forces can be exerted herewith on the extreme edges in order to correct the shape thereof.

As shown in figure 5, a pressure force that is for instance substantially axial can be exerted on the lower edge of the rim by making use of yet another pressure member 27.

The different pressure members (see figures 3 (20) , 4 (26) , 5 (27) , are easily exchangeable and can all be coupled to the pressure cylinder 19. Which of the pressure members is used and in which sequence the diverse treatments take place depends greatly on the nature and extent of deformation.

Figure 6 shows a device 28 comprising a frame 29 on which a rim 1 can be placed. Use is made of a centering attachment having in this embodiment a disposition of four positioning pins which fit into the bolt holes in the hub 31 of the rim for positioning a rim on the basis of a pin/hole connection. Depending on the pitch of the rim for treating the number of pins can also amount to three or five.

The frame 29 bears a supporting member 32 with three arcuate steps 33, 34, 35 for accommodating rims of different diameters. It will be apparent that the steps 33, 34, 35 have differing radii of curvature, each corresponding with the radius of curvature of a rim for treating.

The frame slidably supports a pressure cylinder 36 with a pressure member 37 in the form of a curved profile. A deformed zone 38 is designated schematically. Here this is an axial deformation oriented inward which has to be corrected by the pressure force 9. it will be apparent that in all the cases described use is made of a mild pre-heating and a strong, local post-heating prior to the correcting mechanical deformation treatment being performed.

The foregoing relates only to examples of the invention. Different corrections may be necessary subject to the wishes of users and the nature and extent of the deformations for correcting.

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Claims

X Sch/EN/1-pctClaims

1. Method for restoring a plastically deformed light-metal rim to the original shape, which method comprises the steps of:

(1) providing a plastically deformed light-metal rim; (2) heating the rim to a first temperature i the range of 80-140°C;

(3) subsequently heating the rim locally in the zone of a deformation for repair to a second temperature in the range of 200-300°C; (4) exerting a pressure force on the rim in the zone of the deformation for repair counter to the direction of the plastic deformation present such that the zone of the deformation is subjected to an oppositely oriented deformation which is an amount the size of the elastic deformation greater than the plastic deformation for repair.

2. Method for performing the method as claimed in claim 1, comprising: first heating means for heating the rim to a temperature in the range of 80-140"C; second heating means for locally heating the rim to a temperature in the range of 200-300°C; pressure means for applying a local pressure force on a zone of the rim for treating.

3. Device as claimed in claim 2 , characterized in that the pressure means comprise a pressure cylinder bearing on its one end a pressure distribution plate, whereof the radius of curvature corresponds with the radius of curvature of the relevant portion of the inner surface of the rim, and bearing on its other end a pressure plate whereof the radius of curvature is smaller than the radius of curvature of the original shape of the zone for treating, this such that in the operating situation the pressure means extend in the diagonal direction of the rim and can push off against this rim.

4. Device as claimed in claim 3, characterized by locking means blocking the axial movement of the pressure means.

5. Device as claimed in claim 2, characterized by a frame with positioning means for fixedly positioning a rim relative to that frame, which frame also bears the pressure means such that the pressure means can support between the frame and the rim.

6. Device as claimed in claim 5, characterized in that the positioning means comprise a supporting member, the inner surface of which has at least two arcuate steps with different radii of curvature for supporting rims with correspondingly differing diameters.

7. Device as claimed in claim 2, characterized in that the first heating means comprise an oven.

8. Device as claimed in claim 2, characterized in that the _'second heating means comprise a burner.

9. Device as claimed in claim 2, characterized by a centering attachment provided with a number of centering pins for placing and holding a rim for treating in a desired treating position by means of pin/hole connections with the screw apertures present in a rim.

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