US3869893A

US3869893A - Coining press

Info

Publication number: US3869893A
Application number: US380867A
Authority: US
Inventors: John Edward Plaister; Leonard Edward Cole
Original assignee: Taylor and Challen Ltd
Current assignee: Taylor and Challen Ltd
Priority date: 1972-07-21
Filing date: 1973-07-19
Publication date: 1975-03-11
Anticipated expiration: 1992-03-11
Also published as: GB1381675A; DE2336122A1

Abstract

A collar plate assembly of a coining press comprising an annular collar plate in which each blank is received and supported on a lower die for coining, and inlet connection means for a pressurized air supply which communicates with the peripheral region of the collar plate so that in use air escapes upwards around the periphery of the collar plate so as to resist the ingress of metal oxide powder. Ingress of metal oxide powder is also prevented by an annular filter of resilient material which is permanently compressed between the collar plate and die support member beneath it.

Description

United States atent [1 1 Plaister et al.

[4 1 Mar. 11, 1975 COINING PRESS [73] Assignee: Taylor & Challen Limited,

Birmingham, England [22] Filed: July 19, 1973 [21] Appl. No.: 380,867

[30] Foreign Application Priority Data July 21, 1972 Great Britain 34155/72 Novv 4. 1972 Great Britain 50911/72 [52] US. Cl. 72/39, 72/482 [51] Int. Cl. B211) 45/04 [58] Field of Search 72/470, 466, DIG. 3, 38, 72/39, 478, 470, 482; 83/168, 169

[56] References Cited UNITED STATES PATENTS 2.442.901 6/1948 Missbach 83/168 2,679,175 5/1954 Davis 72/39 Primary Examiner-C. W. Lanham Assistant Examiner-Robert M. Rogers Attorney, Agent, or FirmScrivener Parker Scrivener and Clarke ABSTRACT A collar plate assembly of a coining press comprising an annular collar plate in which each blank is received and supported on a lower die for coining, and inlet connection means for a pressurized air supply which communicates with the peripheral region of the collar plate so that in use air escapes upwards around the periphery of the collar plate so as to resist the ingress of metal oxide powder. ingress of metal oxide powder is also prevented by an annular filter of resilient material which is permanently compressed between the collar plate and die support member beneath it.

6 Claims, 2 Drawing Figures COINING PRESS This invention relates to the collar plate assembly of a coming press.

Individual blanks in a coining press are coined in an annular collar plate which is mounted in an assembly surrounding the lower die. The assembly comprises an outer sleeve and a support plate attached to it at its upper end, the collar plate which is received in an aperture in the support plate and is spring urged upwards to seat against the support plate, and a support member for the lower die which is housed within the outer sleeve so that it can move axially therein. The upper end of the support member is adapted to releasably hold the lower die so that the latter engages within the central bore of the collar plate and can support a blank therein during coining and can subsequently be moved upwards by the support member to eject the coined blank from the collar plate.

A difficulty which arises with known collar plate assemblies is that the metal oxide film which is often present on the blanks breaks loose as powder during the coining operation and works down into the assembly and causes moving components such as the die support member or members associated with the spring support means of the collar plate to sieze-up mechanically. The assembly does not then operate correctly during coining and it or other parts of the press may be damaged as a result. The ingress of metal oxide powder is particularly aided by the movement of the lower die and its support member within the assembly, this producing a suction effect which helps to locate each blank in the bore of the collar plate but which also draws the pow der into the assembly.

The object of the present invention is to provide a collar plate assembly which is adapted so as to prevent or reduce the ingress of metal oxide powder which might hinder proper operation of the assembly.

This object is achieved according to the present invention by providing a pressurised air supply to the assembly so that air escapes upwards from it in the peripheral region ofthe collar plate and thereby resist the ingress of metal oxide powder.

According to another feature of the invention an annular filter is provided around the lower die between the underside of the collar plate and the upper end of the lower die support member. Preferably, this filter is an annular pad of a resilient porous material which is permanently compressed between the collar plate and die support member such that downwards movement of the die support member allows the pad to expand and produce a suction effect. This suction effect helps to locate the blanks but the pad prevents any metal oxide powder from being drawn past it further into the assembly.

The invention will now be described by way of example with reference to the accompanying drawings in which;

FIG. 1 is a plan view of a collar plate assembly according to the invention, and

FIG. 2 is a cross-section taken along the line 2-2 in FIG. I.

An outer support assembly 1 is formed by a member 2 with an axial bore 3, and upper and lower end plates 4 and 5 which are connected to the member 2 by screws 6. The collar plate 7 is connected to a cylindrical sleeve 8 via a clamping ring 9 which is connected to the sleeve 8 by screws 10, and these assembled

members

7, 8, 9 are mounted within the outer support assembly so that the collar plate 7 and ring 9 are received within an aperture 11 in the upper end plate 4, and the sleeve 8 is a slide fit within the member 2 and is axially confined between portions of the end plates 4 and 5. Small spring assemblies 12 are provided within blind holes in the lower face of the sleeve 8 so as to act between the sleeve and the lower end plate 5 and urge the sleeve and collar plate upwards. The lower die 13 is mounted at the upper end ofa die support member 14 which is a slide fit within the sleeve 8. A plastic bearing liner 15 is provided between the support member 14 and sleeve 8 and spring loaded plungers 16 are provided in the support member 14 so as to act upwards against the collar plate and thereby urge the support member 14 downwards into engagement with actuating means (not shown) separate from the collar plate assembly.

ln use fine metal oxide powder from the coined blanks will collect on the upper surface of the collar plate 7, ring 9 and end plate 4, and unless precautions are taken this will penetrate between the periphery of the ring 9 and the bore 11 in the end plate 4 to the cylindrical bearing surface between the outer member 2 and sleeve 8. There would then be a high risk of these members seizing solid, whereupon the sleeve 8 and collar plate 7 would not be free to move axially to absorb coining forces and the dies or die assemblies could be damaged. The chance of this occuring is reduced according to the invention by providing an upwardly flowing curtain of air between the ring 9 and upper end plate 4.

The air is supplied to the assembly from a pressurised supply through an inlet connection 17 and a passage 18 in the member 2 to an annular channel 19 in the upper face of the member 2. This channel 19 communicates with further radially directed channels 20 in the lower face of the upper end plate 4, and these channels 20 communicate at their inner ends with an annular groove 21 in the outer circumferential face of the ring 9. Air supplied to the groove 21 escapes upwards between the ring 9 and the bore 11 in the end plate 4 to produce said curtain of air which resists the ingress of the metal oxide powder.

Preferably, the outer cylindrical surface of the sleeve 8 is dimpled so that any small amount of metal oxide powder which might penetrate between the sleeve and outer member 2 will accumulate in the dimples and not cause seizure. These dimples can be easily formed by knurling the outer surface of the sleeve before hardening and subsequently removing the tops of the knurled formation by grinding to leave a dimpled pattern.

The metal oxide powder will also penetrate into the collar plate assembly through the central bore in the collar plate around the edge of the lower die 13. In fact, such ingress of powder is positively aided by the periodic downward movements of the lower die 13 and its support member 14 which produce a suction effect. However, according to a further feature of the invention an annular filter 22 is provided between the collar plate 7 and upper end of the die support member 14 which prevents the powder from penetrating to the bearing liner l5 and possibly causing the die support pressed therebetween. Downward movement of the die support member from the illustrated position allows the pad to expand slightly and the increased space of the pores within the pad help produce the suction effect to draw the next blank into the bore of the collar plate. The pad is still compressed, however, even at the bottom of the stroke of the die support member and no powder can pass through or past the pad. The pad 22 can be replaced or cleaned periodically, for instance at each die change, to maintain the suction effect.

We claim:

1. A collar plate assembly for a coining press comprising an outer support assembly and a die support member enclosed within said support assembly so as to be movable relative to the latter along an axis which is substantially vertical in use, said support assembly comprising a support plate at its upper end with an aperture through it, a collar plate which is received in said aperture in the support plate, means which spring urges the collar plate upwards, and inlet connection means for a pressurized air supply which communicates with the peripheral region of the collar plate so that in use the air from the pressurized supply escapes upwards around the whole periphery of the collar plate so as to resist the ingress of powder into the collar plate assembly.

2. An assembly as claimed in claim 1 in which said outer support assembly comprises an outer member which has a bore therethrough that receives said die support member and which is connected to said support plate at its upper end, and in which a channel is defined by mating surfaces of the outer member and support plate around the collar plate and said inlet connection means is mounted on said outer member and communicates with said channel.

3. An assembly as claimed in claim 2 in which said channel communicates with said aperture in the support plate through a plurality of inwardly directed channels spaced around the aperture.

4. An assembly as claimed in claim 3 in which a clamping ring surrounding the collar plate clamps the latter to a sleeve which is a slide fit in said bore of the outer member, and in which an annular groove is formed around the outer edge of said clamping ring so as to be closed by the face of the aperture in the support plate and to communicate with said inwardly directed channels.

5. An assembly as claimed in claim 1 in which an annular filter is provided between said collar plate and the upper end of said die support member so as to prevent the passage of powder from the central bore of the collar plate to the die support member below the filter.

6. An assembly as claimed in claim 5 in which the filter is made of a resilient material and is permanently compressed between the collar plate and die support member.