GB2131335A - Punch assembly - Google Patents

Abstract

A punch assembly comprises a nest 12 of dies (14, Figure 2) in predetermined relationship with a corresponding group of punches (18, Figure 3) carried on a block 16. Drive means 22, e.g. hydraulic ram, manually-operated ratchet means, actuate the punches, and locating means, e.g. a gauging stop (50, Figure 4) position the workpiece, e.g. an electrical earth tape, relative to the dies. A stripper plate 40 is pivotally mounted to allow access to the dies and guide pillars (24, Figure 3) or the punch block engage in holes (26, Figure 2) in the die nest 12. <IMAGE>

Description

SPECIFICATION Punch This invention relates to a punch arrangement and in particular to a punch arrangement for producing a predetermined pattern of holes in a metal strip.

In electrical installations such as electricity sub stations and the like metal parts must be earthed and this is usually accomplished by means of a conducting strip of material known as an 'earth tape'. Earth tapes are metal strips, usually copper, of dimensions appropriate to the maximum current load, for example 50mm x 6mm or 25mm x 3mm. When it is desired to join two lengths of an earth tape, either to increase the length thereof or to T-off, the usual method is to drill a series of holes in each of the tapes to be joined and mechanically affix the tapes to one another by means of rivets, for example 'pop' rivets. The holes are drilled and, in order that they should match up on each of the pieces to be joined, the portions to be drilled may be marked out before drilling.Owing to errors both in the marking and the drilling, the holes are often out of register requiring further adjustment and/or redrilling on behalf of the operator. Thus the current method is both inaccurate and time consuming.

The invention seeks to provide a punching device capable of producing accurately aligned holes which will overcome or reduce the disadvantages of the prior method.

According to the present invention there is provided a punch assembly which comprises a nest of dies in predetermined relationship and a corresponding group of punches carried on a block, means being provided to urge the punches into making engagement with the dies, and locating means being provided for locating an article to be punched with respect to the dies.

The punch assembly of the invention is intended for on site operation and is therefore preferably built self contained and portable. Furthermore, in order to accommodate different sizes of earth tape, the die nest and corresponding punch block are preferably simply removable to enable replacement with different sizes.

The die nest and the punch block may be held within a suitable frame, and the means for urging the punches into engagement with the dies may comprise a manually operated means such as a screw thread and ratchet arrangement that preferably comprises a power operated ram, for example hydraulic ram arrangement. The means for locating the article to be punched with respect to the dies may conveniently comprise one or more stops, which may be adjustable.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which; Figure 1 is an elevational view of an assembly in accordance with the invention; Figure 2 is a plan view of the die nest employed in Figure 1; Figure 3 is a corresponding punch block; Figure 4 is a view taken on line IV - IV in Figure 1; and Figure 5 is a view of the assembly of Figure 1 from beneath.

Referring to the drawings a punch assembly generally designated 10 comprises a die nest 12 within which are fixed five circular dies 14. A punch block 16 is located above the die nest 12 and carries five punches 18 corresponding to each of the dies 14.

The punch block 16 is slidably mounted within a general framework 20 and may be urged into making engagement with the die nest 12 by means of a hydraulic cylinder 22. The punch block 16 is maintained in the correct spatial relationship with the die nest 12 by means of four pillars 24 which locate in corresponding holes 26. The holes 26, and therefore the corresponding pillars 24, may be offset slightly from a square configuration so as to enable the punch block be aligned with the die nest in one position only.

The die nest 12 is retained in a base member 28 which is connected to the remainder of the frame 20 by means of pillars 30 which pass through the base 28 and are retained on the underside thereof by means of a metal spider 32 having channels 34 of sufficient width to locate within grooves 36 adjacent the bottoms of each of the pillars 30.

A lever arm portion 38 is provided to rotate the spider 32 thereby releasing the pillars 30 and enabling the frame 20 to be removed from the base 28 very quickly and easily so that access may be obtained to the die next and punch block.

The article which is to be punched, which will normally be a copper strip, is inserted into the apparatus between the pillars 30 and is retained beneath a stripper member 40 which is pivotally attached to the body at 42 and releasably attached at 46 so that it may be hinged upwardly away from the die nest to allow access to the die nest. The stripper plate 40 has five holes 48 corresponding to the punches 18 and dies 14.

A stop member 50 is provided on the die nest 12 against which the strip to be punched is butted in use so as to predetermine the distance from the butted edge at which the holes will be punched.

Certain embodiments of the abuttment 50 may be spring loaded so that the device can accommodate wider strips of material with the abuttment 50 recessed into the die nest 12 underneath the strip which is then located by a fixed abuttment set further back from the die nest.

In use, an earth tape is inserted between the strip 14 and the die nest 12 until it butts against the abuttment 50. At this stage the hydraulic cylinder 22 is actuated causing the punch block 16 to move downwardly and the punches 18 to punch holes in the earth tape in conjunction with the dies 14. Once the holes have been punched the cylinder 22 may be reversed causing the block 16 to lift upwardly. Any tendency for the earth tape to be retained on the punches 18 and therefore rise with them, will be overcome by the stripper plate 40 which will effectively strip the punched earth tape from the punches 18 and allow it to be withdrawn from the punch assembly.

Should it be necessary to gain access to the assembly for any reason, for example to change the punch block 16 and die nest 12 for a different size, or to release a jammed article, then the lever 38 is operated to release the pillars 30 thereby disassembling the device and allowing access to the punch block 16 and the die nest 12 which can thereby be quickly replaced if desired.

The assembly of the invention is compact enough to be used on site and produces punched holes in an earth tape extremely quickly and very accurately, enabling accurate joins to be made quickly by a technician rivetting in the normal way.

CLAIMS (Filed on 28.11.83.) 1. A punch assembly which comprises a nest of dies in predetermined relationship a corresponding group of punches carried on a block, means being provided to urge the punches to mating engagement with the dies, and locating means being provided for locating an article to be punched with respect to the dies.

2. An assembly as claimed in claim 1 in which the die nest and corresponding punch block are removable to enable replacement with different sizes.

3. An assembly as claimed in either of claims 1 or 2 in which the die nest and punch block are held within a suitable frame and the means for urging the punches into engagement with the dies are either manually operated or power operated.

4. An assembly as claimed in any one of claims 1 to 3 in which the driving means comprises a manually operated screw thread and ratchet engagement.

5. An assembly as claimed in any one of claims 1 to 3 in which the driving means comprises a power operated ram.

6. An assembly as claimed in claim 5 in which the ram is a hydraulic ram arrangement.

7. An assembly as claimed in any one of claims 1 to 6 in which the means for locating the article to be punched with respect to the dies comprises one or more adjustable stops.

8. A punch assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. assembly for any reason, for example to change the punch block 16 and die nest 12 for a different size, or to release a jammed article, then the lever 38 is operated to release the pillars 30 thereby disassembling the device and allowing access to the punch block 16 and the die nest 12 which can thereby be quickly replaced if desired. The assembly of the invention is compact enough to be used on site and produces punched holes in an earth tape extremely quickly and very accurately, enabling accurate joins to be made quickly by a technician rivetting in the normal way. CLAIMS (Filed on 28.11.83.)

1. A punch assembly which comprises a nest of dies in predetermined relationship a corresponding group of punches carried on a block, means being provided to urge the punches to mating engagement with the dies, and locating means being provided for locating an article to be punched with respect to the dies.

2. An assembly as claimed in claim 1 in which the die nest and corresponding punch block are removable to enable replacement with different sizes.

3. An assembly as claimed in either of claims 1 or 2 in which the die nest and punch block are held within a suitable frame and the means for urging the punches into engagement with the dies are either manually operated or power operated.

4. An assembly as claimed in any one of claims 1 to 3 in which the driving means comprises a manually operated screw thread and ratchet engagement.

5. An assembly as claimed in any one of claims 1 to 3 in which the driving means comprises a power operated ram.

6. An assembly as claimed in claim 5 in which the ram is a hydraulic ram arrangement.

7. An assembly as claimed in any one of claims 1 to 6 in which the means for locating the article to be punched with respect to the dies comprises one or more adjustable stops.

8. A punch assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.