GB2259880A

GB2259880A - Apparatus and method for press forming of articles

Info

Publication number: GB2259880A
Application number: GB9219093A
Authority: GB
Inventors: David Waterworth; Mark Stone
Original assignee: Decorpart Ltd
Current assignee: Decorpart Ltd
Priority date: 1991-09-11
Filing date: 1992-09-09
Publication date: 1993-03-31
Anticipated expiration: 2012-09-09
Also published as: GB2259880B; GB9119418D0; GB9219093D0

Abstract

In, for example, a transfer press a workpiece A is pressed at a workstation to form a cup and then at a further workstation is both pressed further to form a narrower and deeper cup 18 and is trimmed to remove a peripheral lip 17. A trimming device 24 is mounted on a press member 32 and an ejector 23 removes the finished cup or sheath 18 upwards out of die 21. The trim device 24 may have laterally inner and outer cutting edges 31, 33. <IMAGE>

Description

APPARATUS ANB METHODS FOR PRESS FORR#ING OF ARTIClES This invention relates to apparatus and methods for press forming of articles.

According to one aspect of the invention a method of forming an article by pressing on a workpiece at a work station comprises pressing the workpiece into a die to shape the workpiece and, at the workstation, removing unwanted material from the shaped workpiece.

The shaped workpiece may have an open end and the unwanted material may be a peripheral lip at the open end.

The material may be removed when the shaped workpiece is in the die.

According to another aspect of the invention apparatus for use in shaping a workpiece at a workstation comprises a die, a press member for pressing the workpiece into the die to shape the workpiece, and a trim device for removing at the workstation unwanted material from the shaped workpiece.

The trim device may include laterally inner and outer cutting edges.

The trim device may be slidable on the press member.

The apparatus may îorm part of a press, e.g. a transfer press.

The invent Ion may be performed in various ways and one specific embodiment with possible modifications will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a diagrammatic view of part of a transfer press; Fig. 2 shows a sequence of steps in forming a deep drawn cup or sheath; Fig. 3 shows a sequence of steps in forming a deep drawn cup or sheath according to the invention; Fig. 4 is a diagrammatic showing of steps in forming a cup or sheath according to the invention; and Fig.5 is a section through a die assembly.

A transfer press 10 has a plurality of work stations and a workpiece is sequentially moved through the stations and is operated on at the stations. At the stations typically a press member 11 co-operates with a die 12. The press members 11 move up and down together and an ejector at each station ejects the workpiece at that station into a transfer device indicated schematically at 13 which transfers the workpiece at each station to the next station ready to be operated upon by the press member at that station.

Thus in the example of Fig. 2, a blank 14 is cut at station A from a strip (not shown) e.g. of metal drawn from a supply roll; the cut blank is moved to station B where the blank 14 is partly pressed or drawn by the respective press member into the die to form a cup shape 15 having a closed end 15a and an open end 15b; this cup 15 is moved to station C where the cup is pressed or drawn to final narrower and longer size 16; and this is moved to station D where the unwanted material forming a peripheral lip 17 at the rim is cut or trimmed off to leave the finished cup 18. The cup 18 may receive further treatment at another work station.

It will be understood that when the transfer press is operating, there is a work piece 14,15,16,18 at each of the respective work stations.

In a method of the present invention, see Fig.3, the pressing and trimming occur at the same work station.

Thus as shown in Fig. 4, a die 20 for use at station C has die part 21 defining the outer diameter of the cup 16. A part-formed cup 15 is positioned above the die 21, a press member 52 descends to draw the cup 15 into the desired cross-section shape and length 16, the closed end 22 of the cup 16 engaging the end of an ejector 23 which is pushed downwards by the press member. A trim or clip device 24 which is slidably received on the press member 32, descends, whilst the press member 32 is still in the cup 16, to separate the trim 17 leaving the finished cup 18 in the die.The press member 32 is then raised out of the die with the trim device 24 which carries the trim 17, the now-formed cup member 18 being thus removed from the press member and the ejector 23 is then moved upwards to eject the cup 18 from the die, the cup 18 being removed for example by mechanism 13.

The separated trim 17 is stripped from the device 24 by engagement with a fixed stripper 40 as the device 24 moves upwards to its top position and can then be removed from the work station by for example compressed air.

This method provides the benefits of reduced handling, reduced press setting time and reduced tooling costs as compared with the method of Fig. 2.

Fig.5 shows a die assembly 30 for use at station C, with the ejector 23 in a raised position and the press member 32 in a part-lowered position. It will be noted that the lower cutting end 31 of the trim device 24 is slightly inclined or stepped inwards to form a laterally inner cutting edge 31 with the final trim break being made at axially spaced outer shoulder/edge 33. The axial distance between edges 31, 32 varies with different cups and wall thicknesses but is similar to the axial extent of the radius at the junction between the cup wall and the trim. The downward movement of device 24 forces the cut trim 17 on to the larger diameter part of device 24 adjacent edge 33.

the cups 18 may for example be used as sheaths on perfume bottles.

The invention can be used in other forms of draw press.

Claims

1. A method of forming an article by pressing on a workpiece at a workstation comprising pressing the workpiece into a die to shape the workpiece and, at the workstation, removing unwanted material from the shaped workpiece.

2. A method as claimed in Claim 1, in which the shaped workpiece has an open end and the unwanted material comprises a peripheral lip at the open end.

3. A method as claimed in Claim 1 or Claim 2, in which the material is removed when the shaped workpiece is in the die.

4. A method of forming an article by pressing on a workpiece at a workstation substantially as hereinbefore described with reference to Figs. 3 and 4.

5. An article made by a method as claimed in any preceding claim.

6. Apparatus for use in shaping a workpiece at a workstation comprising a die, a press member for pressing the workpiece into the die to shape the workpiece, and a trim device for removing at the workstation unwanted material from the shaped workpiece.

7. Apparatus as claimed in Claim 6, in which the trim device is slidable on the press member.

8. Apparatus as claimed in Claim 6 or Claim 7, in which the trim device has laterally inner and outer cutting edges.

9. Apparatus for use in shaping a workpiece at a workstation substantially as hereinbefore described with reference to and as shown in Fig. 4, or Fig. 5, of the accompanying drawings.

10. A press including apparatus as claimed in any of Claims 7 - 9.

11. A transfer press as claimed in Claim 10.