GB2089705A

GB2089705A - Embossing die assembly

Info

Publication number: GB2089705A
Application number: GB8134759A
Authority: GB
Original assignee: HINES ENGINEERS EDWARD Ltd
Current assignee: HINES ENGINEERS EDWARD Ltd
Priority date: 1980-12-23
Filing date: 1981-11-18
Publication date: 1982-06-30
Also published as: GB2089705B

Abstract

A die assembly for embossing a series of letters and numerals in metal sheets to form number plates for motor vehicles comprises a frame (15) which holds and locates seven capper dies side by side. Each clapper die comprises a top plate 1 and a bottom plate 2 hinged together by a hinge pin 7 in a slot 8 and the plates have embossing formers 10 and 11 fixed to them by an adhesive, which is preferably an epoxy resin. The plates 1 and 2 are biassed apart by a spring 12. To emboss a number plate 18, the plate is placed in position on the frame (15) under the top plates 1 of the clapper dies and the clapper die assembly with the number plate is placed in a press which presses the capper die plates 1 down to emboss the plates between the embossing formers 10 and 11. <IMAGE>

Description

SPECIFICIATION Embossing die assembly This invention relates to die assemblies for embossing, with the aid of a press having plattens, a series of letters and numerals in metal sheets to form number plates for motor vehicles.

According to this invention, such an assembly comprises a number of clapper dies, for example seven, and a jig having means for holding the dies and locating them side by side in a row, each clapper die comprising upper and lower backing plates which are connected together along one edge of each plate by a hinge, the plates being biassed apart about the hinge and being arranged to receive between them a male embossing former and a female embossing former which, in use, are fixed one to each of the plates, and the hinge being constructed so that it provides a limited freedom of movement of the plates towards and away from each other at the hinge axis, the assembly being arranged to be fitted between the plattens of a press to enable the plattens to press the backing plates together with a metal sheet between the formers, and the freedom of movement provided by the hinge allowing the backing plates to lie parallel to each other during the pressing movement.

This assembly has a number of advantages over prior dies used for forming embossed number plates for vehicles. Firstly, it is common for a series of number plates with successive numbers to be made at one time and, when this is done, it is only necessary to alter one or at the most two numerals between successive operations in the manufacture of up to ninety nine number plates. With the assembly in accordance with the invention, these numerals can be changed very quickly indeed by exchanging one or two of the clapper dies in the jig between successive pressing operations and this enables the series of pressing operations to be carried out much more quickly than has previously been possible.

Secondly, in Great Britain, although there is a statutory minimum heightforthe numerals and letters on a vehicle number plate, the style of the numerals and letters varies from one manufacturer to another and indeed several different styles of letters and numerals are at present commonly used.

By making the male and female embossing formers as separate parts of the clapper dies, instead of forming them integrally with the backing plates as has previously been done, the tooling costs in the manufacture of a large number of clapper dies for producing numerals and letters of different styles is very greatly reduced.

The male and female embossing formers may be fitted to the clapper dies as an entirely separate operation, but they may form part of the assembly in accordance with the invention. The formers are preferably of hard aluminium and this has been found to stand up very satisfactorily to the pressure and wear when the metal number plate is of aluminium or aluminium alloy. The formers preferably have flat faces in contact with the faces of the backing plates and they are then detachably fixed to the faces by means of an adhesive, which may for example be an epoxy resin.

The jig preferably comprises a rectangular frame having two opposite sides between which the hinged ends and the opposite ends of the clapper dies fit to locate the dies in one direction, and two further opposite sides between which an integral number of the dies fit side by side to locate the dies in a second direction at right angles to the one direction.

Preferably the frame also includes means for locating a number plate to be embossed by the dies so that in an embossing operation the various numerals and letters are embossed on the plate in accurate positions.

Further advantages of the provision of separate formers which are detachably fixed to the backing plates by an adhesive are that when the formers wear out, they can easily be replaced without it being necessary to replace the complete clapper die and also, if it desired to alter the style of the numerals or letters, new formers can be substituted for those already fixed to the backing plates.

Preferably, the freedom of movement of the backing plates towards and away from each other at the hinge axis is provided by forming the hinge with a hinge pin which fits in round holes in one backing plate and in slotted holes in the other backing plate, the slotted holes having their lengthwise direction extending at right angles to the face of the backing plate.

Preferably also, the backing plates are biassed away from each other by means of a substantially U-shaped, or hairpin, spring made of flat-sectioned strip, the spring fitting around the hinge pin and having one arm in engagement with each of the backing plates.

An example of an assembly in accordance with the invention is illustrated in the accompanyin drawings in which: Figure 1 is a side elevation of one of the clapper dies of the assembly; Figure 2 is a plan view of the clapper die shown in Figure 1; Figure 3 is an end view of the clapper die as seen in the direction of the arrow Ill in Figure 1; Figure 4 is a plan view of the whole assembly showing a frame forming a jig with seven clapper dies as shown in Figures 1 to 3 fitted into the frame; and Figure 5 is an end view of the frame and clapper dies shown in Figure 4 as seen in the direction of the arrow V in Figure 4.

Referring to Figures 1 to 3 of the drawings, each of the clapper dies, of which there are seven in the present example of the assembly, comprises an upper steel backing plate 1 and a lower steel backing plate 2. The plates 1 and 2 are formed in a pressing and stamping operation and each of the plates is formed at its front and back edges with slots 3 and 4 respectively. Only the slot 3 in the upper plate 1 is shown in Figure 2 of the drawings. The upper plate 1 is provided with two downwardly bent lugs 5 and the plate 2 is provided with two upwardly bent lugs 6 which fit between the lugs 5 as shown most clearly in Figure 3 of the drawings.

The plates 1 and 2 are hinged to each other by a hinge pin 7 which passes through circular holes in the lugs 6 and through slotted holes 8 (see Figure 1) in the lugs 5. The hinge pin 7 is held in position by starlock washers 9 fitted to both ends of the pin 7.

As the holes Bin the lugs 5 are slotted, the lugs 5 and hence the adjacent end of the plate 1 have a limited degree of freedom of vertical movement relative to the lugs 6 and the adjacent end of the plate 2. This enables the plates 1 and 2 to lie parallel to each other when the plate 1 is pressed downwards towards the plate 2 between the plattens of a press.

The plate 2 has a male former 10 fixed to its upper surface by epoxy resin adhesive and the plate 1 has a female former 11 fixed to its underside in the same way. The embossing formers 10 and 11 are engraved to cause them to emboss a figure or number on a metal number plate interposed between them when the plates 1 and 2 are pressed towards each other between the plattens of a press.

The plates 1 and 2 are biassed apart from each other by a U-shaped or hairpin spring 12 which is made of springy metal strip and has a portion which extends around the hinge pin 7 and two arms 13 and 14 which engage with the plates 1 and 2 respectively.

The embossing formers 10 and 11 are made of hard aluminium and are fixed to the plates 1 and 2 by the epoxy resin adhesive before the plates 1 and 2 are connected together by the hinge pin 7. To ensure that the formers 10 and 11 are accurately located on the plates 1 and 2 so that they will mate with each other when the clapper die is closed in a press, the plates 1 and 2 are held in position in a jig by means of the slots 3 and 4 and the embossing formers 10 and 11 are then held in position in the jig and are engraved with the appropriate symbols whilst in the jig.

As shown in Figures 4 and 5, seven of the clapper dies as shown in Figures 1 to 3, which are the same as each other exceptforthe letters or numbers engraved on the embossing formers 10 and 11 are fitted into a jig which comprises a rigid rectangular steel frame 15. The plates 2 of the clapper dies are a close fit between two opposite side members 16 and 17 of the frame 15 so that the clapper dies are all located relative to each other in one direction and the frame 16 is provided with a movable spacer piece 18 which enables four of the clapper dies to fit side by side between one side of the spacer piece 18 and a side 19 of the frame 15. Three further clapper dies fit between the other side of the spacer 18 and a side 20 of the frame 15.The four clapper dies fit closely side by side between one side of the spacer 18 and the side 19 of the frame and the three clapper dies fit closely side by side between the other side of the spacer 18 and the side 20 of the frame. In this way all of the clapper dies are accurately located in a direction at right angles to the direction in which they are located between the sides 16 and 17 of the frame 15.

Channel shaped guide pieces 21 and 22 are fixed to the top faces of the sides 19 and 20 respectively and these channel shaped pieces receive and locate the ends of a blank number plate 23 when this is placed in position under the top plates 1 of the row of dies held in the frame 15. The blank number plate is thus held accurately in position in relation to the dies and in particular in relation to the male and female embossing members 10 and 11 for embossing the various letters and digits or numbers on the number plate. The die assembly with the number plate in position is then placed on the lower platten of a press and the press is then operated to bring the upper platten down and close all seven of the clapper dies simultanteously onto the blank number plate to emboss it with the required letters and numerals.

After a number plate has been pressed, the top platten of the press is raised again so that all of the clapper dies are opened by their springs 12 and the embossed number plate can then be removed. One or more clapper dies are then replaced by other clapper dies with different letters or numerals engraved on their embossing members and the new blank number plate is then placed in position between the members 21 and 22. The operation can then be repeated. The change-over of one or more clapper dies to change one or more letters of numerals takes only a moment.

Claims

1. A die assembly for embossing, with the aid of a press having plattens, a series of letters and numerals in metal sheets to form number plates for motor vehicles, the assembly comprising a number, for example seven, of clapper dies, and a jig having means for holding the dies and locating them side by side in a row, each clapper die comprising upper and lower backing plates which are connected together, along one edge of each plate by a hinge, the plates being biassed apart about the hinge and being arranged to receive between them a male embossing former and a female embossing former which, in use, are fixed one to each of the plates, and the hinge being constructed so that it provides a limited freedom of movement of the plates towards and away from each other at the hinge axis, the assembly being arranged to be fitted between the plattens of a press to enable the plattens to press the backing plates together with a metal sheet between the formers, and the freedom of movement provided by the hinge allowing the backing plates to lie parallel to each other during the pressing movement.

2. An assembly according to Claim 1, in which the male and female embossing formers form part of the assembly, the formers having flat faces in contact with the faces of the clapper die and being detachably fixed to the faces by an adhesive.

3. An assembly according to Claim 2, in which the formers are of hard aluminium and the adhesive is a epoxy resin.

4. An assembly according to any one of the preceding Claims, in which the jig comprises a rectangular frame having two opposite sides between which the hinged ends and the opposite ends of the clapper dies fit to locate the dies in one direction and two further opposite sides between which an integral number of the dies fit side by side to locate the dies in a second direction at right angles to the one direction.

5. An assembly according to Claim 4, in which seven dies fit side by side between the two further opposite sides.

6. An assembly according to Claim 5, in which a spacer divides the die into a group of four dies fitting side by side in contact with each other and a second group of three dies fitting side by side in contact with each other.

7. An assembly according to any one of Claims 4 to 6, in which the frame includes means for locating a number plate to be embossed by the dies.

8. An assembly according to any one of the preceding Claims, in which the freedom of movement of the backing plates towards and away from each other at the hinge axis is provided by forming the hinge with a hinge pin which fits in slotted holes in one of the backing plates, the slotted holes having their lengthwise direction lying at right angles to the faces of the backing plates.

9. An assembly according to Claim 8, in which the backing plates are biassed away from each other by means of a substantially U-shaped spring made of flat-section strip, the spring fitting around the hinge pin and having one arm in engagement with each of the backing plates.

10. An assembly according to Claim 1, substantially as described with reference to the accompanying drawings.