GB2216833A

GB2216833A - Method of manufacturing a roller chain

Info

Publication number: GB2216833A
Application number: GB8906205A
Authority: GB
Inventors: Dieter Krause
Original assignee: Arnold and Stolzenberg GmbH
Current assignee: Arnold and Stolzenberg GmbH
Priority date: 1988-03-21
Filing date: 1989-03-17
Publication date: 1989-10-18
Anticipated expiration: 2009-03-17
Also published as: FR2628662A1; GB2216833B; GB8906205D0; FR2628662B1; IT1228807B; DE3809841C1; IT8919853A0; ES2014059A6

Description

2216833 Z.

Method of Manufacturing a Roller Chain The invention concerns a method of manufacturing a roller chain.

Roller chains consist of inner and outer links. The inner links consist of bushes, the inner plates joining these, and rollers borne on the bushes. Held in the bushes are bolts which form the outer link with the outer plates.

For the manufacture of such roller chains, bushes wound from sheet'and also wound or deep-drawn rollers have hitherto been used. Wound bushes and rollers possess a longitudinal seam which reduces the stability and in particular the impact load-bearing capacity of these parts and also entails uneven wear, with the result that the satisfactory function of these chains is no longer guaranteed after a certain operating period. The manufacturing process of bushes and rollers too is relatively expensive.

The problem to which this present invention is addressed, therefore, is to specifyia method, enabling savings in terms of time and material, for the production of a link chain in the form of a roller chain, in which the load-bearing capacity is considerably increased and the wear considerably reduced.

1 This problem is resolved according to the invention by the element indicated in the characterising part of claim 1. Advantageous developments of the method according to the invention derive from the sub- claims.

Because of the fact that the rollers and bushes are manufactured by cold extrusion in each case, they are formed without a seam and also possess a more homogeneous and compact structure than corresponding wound or deepdrawn parts, so that their load-bearing capacity and also their stability can be considerably increased. As a process, cold extrusion is also relatively simple in terms of the method used, and the proportion of scrap accumulated is very low.

For preference, a roller and a bush are manufactured from a common blank. In this way, the cold extrusion stages of roller and bush are linked with one another so that these processes are simplified by comparison with separate production, and also the machine throughput time is reduced. In addition, the scrap proportion is further reduced. Since only one initial material is used, stockkeeping too is less costly.

i i i i i t v- t J Cold extrusion of roller and bush is advantageously carried out in opposite directions, with the blank ideally being upset beforehand on the roller side and reduced in its diameter on the bush side.

The invention is described more closely in the following with the aid of a constructional example shown in Figures 1 to 6. These show the individual process stages of the conversion of a blank into a bush and a roller.

The blank 1 shown in Figure 1 is a solid cylinder with an axis extending in the longitudinal direction, ie horizontally.- The blank 1 is separated by a wire with a corresponding diameter and preferably consists of a coldupsetting case-hardening steel.

Cold extrusion and the machines necessary for this are fundamentally known in the art. This present invention requires a special 5-stage cold extrusion unit. On the basis of conversion of the blank into a bush and a roller, as illustrated in Figure 1 to 6. it is possible for the expert to construct a corresponding cold extrusion unit so that for the purposes of explaining the invention it is not necessary to provide details of the press itself.

--4- In the Figures, the left-hand side represents the press slide side and the right-hand side the matrix side of the die. As Figure 2 shows, the blank 1 is first reduced in its diameter in a matrix and subsequently upset, so as to produce two sections 2 and 3, which are adapted in their diameters to the external diameters of the roller and bush to be formed.

Section 3 of the blank, reduced in diameter, is subsequently coldextruded on the matrix side in a forward direction, so that the bush blank 4 is formed according to Figure 3. Then cold extrusion of the upset section 2 is carried out in a backward direction in the matrix, as a result of which the roller blank 5 according to Figure 3 is produced. In the course of this, the slug 6 left inside the blank at the transition between the bush blank 4 and the roller blank 5 is also pushed slightly into the bush blank 4 and this latter is phased at both ends.

In the subsequent process stage illustrated in Figure 4, the slug 6 is stamped out through the roller blank 5 and simultaneously the bush blank 4 is calibrated on the inside and outside to the particular diameter desired. This is carried out in a matrix with a stamping and calibrating punch.

j 9 In the subsequent process stage according to Figure 5, the bush blank 4 is separated from the roller blank 5, thereby obtaining the finished bush 7. To this end, a stamping sleeve is provided on the matrix side and a stamping punch on the press slide side. The separated bush 7 is ejected on the matrix side. In the last process stage shown in Figure 6, finally, the internal and external diameters of the roller blank 5 are calibrated so as to obtain the finished roller 8, which is ejected on the press slide side.

The bushes and rollers, after an appropriate heat treatment, are conveyed to the respective assigned stations of an assembly system for the roller chains. They are of top quality with regard to material composition and dimensional accuracy.

Claims

1. Method of manufacturing a roller chain in which the inner links are formed at least from bushes, inner plates connecting these and rollers borne on the bushes, characterised in that the rollers and bushes used have in each case been manufactured by cold extrusion.

2. Method according to claim 1, characterised in that a roller and a bush are manufactured from one common blank by cold extrusion in each case.

3. Method according to claim 2, characterised in that the blank possesses a cylindrical shape.

4. Method according to claims 2 or 3, characterised in that the cold extrusion-of roller and bush is effected in opposite directions.

5. Method according to claims 2 to 4, characterised in that the blank is upset on the roller side before cold extrusion and is reduced in its diameter on the bush side.

6. Method according to claims 2 to 5, characterised in that cold extrusion of bush and roller takes place in immediately successive operations.

1 j

7. Method according to claims 2 to 6, characterised in that after cold extrusion of bush and roller, the common slug remaining in these is stamped out.

8. Method according to claim 7, characterised in that calibration of the bush on the inside and outside is carried out at the same time as the stamping out process.

1

9. Method according to claim 8, characterised in that after stamping-out of the slug and calibration of the bush, the latter is separated from the roller.

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10. Method according to claim 9, characterised in that the roller is calibrated on the inside and outside after separation of the bush.

Published 1989 atThe Patent Office. State House, 66,71 High Ho1born, LondonWC1R4TP. Further copies maybe obtained from The PatentOffIce. Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mw7 Cray, Kent, Com 1/87