US3494033A - Portable panel punch - Google Patents

Description

Feb. 10, 1970' Boscg ETAL 3,494,033

PORTABLE PANEL PUNCH Filed Jan. 26, 1968 2 Sheds-Sheet 1 Fig. l

INVENTORS. Andrew J. Bqwo BY Denny L. Em/g wewmjm THE/R ATTORNEYS Feb; 10, 1970 A. J. Bosco ET AL 3,494,033

PORTABLE PA-NEL PUNCH Filed Jan. 26, 1968 2 Sheets-Sheet z k STEP'CI STEP d 4o F/g 5 1 P C Andrew $2 23? BY Denny L. Emig [/44 0a,, Mia/a THE/R ATTORNEYS United States Patent 3,494,033 PORTABLE PANEL PUNCH Andrew J. Bosco, RED. 4, Meadville, Pa. 16335, and Denny L. Emig, Meadville, Pa.; said Emig assignor to said Bosco Filed Jan. 26, 19 68, Ser. No. 700,964 Int. Cl. B26f N00 US. Cl. 30-360 9 Claims ABSTRACT OF THE DISCLOSURE A tool for punching an opening in a panel by closing a punch member against the panel to be cut, applying sufficient force to pull the punch member through the panel and into a die member having a cutting opening corresponding to a cutting face of the punch member. The punch member is removeably secured in a base member, and the cutting opening of the die member into which the punch member travels during operation of the punch is formed by inserts releaseably secured in the die member.

This invention relates to punching tools and specifically to a portable tool for use in punching a panel to provide an opening therein of desired configuration.

Our invention is useful in forming panel openings for electrical light switches. More particularly, our punch is useful for making rectangular openings in industrial electrical switch boxes for mounting one or a plurality of control switches. It is in the latter application where the advantages of our new punch are most apparent.

Industrial plant electricians carry what is known as a belt which contains a large number of tools including pliers, wire cutters, strippers, etc., all used in the trade. The bulk and weight of the belt (often exceeding 20 pounds) make a physical demand on its wearer; hence, any tool proposed for addition to the belt must not only have strength and utility, but be both light and compact.

Additionally, a useful tool must be suitable for extended periods of time without maintenance, efficient and as safe as possible to operate, and repairable with a minimum expense. Our punch meets all these requirements.

Present panel punches have several drawbacks. Most metal punches are not portable in that they require a separate bed or are useful only with a stationary press. Many are operable by striking the punch with a mallet. Those which can be carried to the job site require the use of an anvil to stabilize the workpiece and absorb the force of a mallet blow. Several types exhaust the punched blank from the punch. These are unsuitable for usev in and around electrical switch boxes which contain exposed electrical current carrying switches, relays and cable leads. Finally, none can be sharpened, repaired or renewed easily, if at all, and most are discarded when the punch member or cutting edges wear, at a high replacement cost.

Basically, our novel punch comprises a die member and a punch member which are adapted to close together against a panel of sheet metal, plastic or other material to be punched. In this connection, the word panel is used to define any workpiece which is thin in at least one dimension such as sheet or strip. The die member carries inserts which form cutting edges with which a punch member, carried by a base member, engages to punch a panel between them. The die member and the base member are aligned by means of pins which extend from the base member, through holes formed in the panel, and into the cutting insert of the die member. A bolt carrying a tension absorbing thrust bearing extends through the die member and a hole in the panel, suitably drilled for the purpose, and is threaded into the punch member.

A feature of the punch is a template, first useful for drilling in the panel the necessary holes for the aligning pins and bolt, and which may be next useful for determining the maximum thickness of metal which can be cut by our punch, as will be explained hereinafter. When the die and base members are properly aligned, one on either side of the panel, the bolt is threaded into the punch member and torqued to close the die and base members to force the punch through the panel, past the cutting edges to form the desired opening.

The blank punched remains on the bolt and within the insert-carrying die member and, in the case of an electrical circuit box, outside the box and away from hot wires. The base member inside the box is retained in the panel by the punch member and the aligning pins until it is physically removed, avoiding contact with any of the electrical circuits in the box.

One or a number of punches can be manufactured easily and economically since all closely toleranced openings in the punch are formed by drilling or milling and none need be hand filed or broached.

Having described our invention broadly, details of its structure, operation, and utility will become apparent from the following description and the accompanying drawings in which:

FIG. 1 is an exploded view showing the elements of our preferred portable punch;

FIG. 2 is a plan view of our improved portable punch;

FIG. 3 is an elevational view of our punch showing the relationship of the punch elements to one another;

FIG. 4 is a side elevational view of the punch shown in FIG. 3; and

FIG. 5 illustrates the sequential steps a through d followed in applying our punch to form an electrical switch opening in a panel.

Referring to FIGS. l-4, we have shown the elements of our novel portable panel punch and their relative position to one another. The punch comprises a die member 10, preferably made of steel. An opening 11 is located centrally in the die member 10. The opening 11 is shown as a rectangular opening, but may be of any desired configuration. As shown, the size of the opening 11 approximates the size of the opening in a standard electrical wall switch panel, with respect to which our punch will be described. At either end of the central opening 11 and extending through die member 10 is a pair of holes 12, which correspond to screw holes in a standard electrical switch panel (FIG. 5d).

The die member 10 includes sidewalls 13- which run the length of the die member and are spaced from one another to provide a longitudinal slot 14 in the surface of the die member 10. A pair of substantially similar insert sections 16 and 17, preferably made of tool steel, are adapted to be inserted in opposed relationship within the longitudinal slot 14 in the die member 10. A slot 18 is provided in each insert section 16 and 17 along an edge thereof. These may be milled in the insert sections.

At either end of the slot =18 along the same edge is a seim-circular groove 19 which comprises half a hole formed when the insert sections 16 and 17 are mated in opposed relation within the longitudinal slot 14 of the die member 10. Similarly, the slots 18 of the insert sections 16 and 17, when opposed within the slot 14 in the die member 10, provide a central opening which is aligned with the opening 11 in the die member.

It is to be understood that the opening 11 in the die member may be formed by one of a number of conventional methods. The opening 11 may be made 'by drilling a series of holes and hand filing to rough dimensions to a size at least as large as the opening formed by the opposed slots 18. The opening 11 may also be broached in the die member 10 according to well-known methods.

When positioned within the longitudinal slot 14, the insert sections 16 and 17, which may be made of magnetic steel, are secured within the die member by a plurality of fastening means, such as Allen head screws 20, three of which are shown in FIG. 1. The Allen screws are inserted through bores 21 in a sidewall 13 of the die member and are threaded into abutting relationship with a face 22 of one of the insert sections 16 and 17.

A base member 23 comprises two base elements 24 and 25. When joined together, face 26 of the base element 24 and 27 of base element are substantially planer and provide a continuous working surface for the base member 23 (FIG. 4). A slot 28 is provided in element 24. When the elements 24 and 25 are joined together, the slot 28 is substantially closed to form an opening which extends through the base member and is substantially aligned with the opening formed by the opposed slots 18 of the insert sections and the opening 11 in the die member 10. The base element 25 is secured to the base element 24 by Allen cap screws, two of which are shown at 25a, which extend through bores 25b in the element 25 and are threaded into and engage threaded holes 29 in element 24.

A punch member 34) having a cutting face 31 each corner of which comprises a cutting point is secured in the base member 23. Body 32 of the punch member 30 is inserted in slot 28 and held in place by the base elements 24 and 25 which are tightened by Allen cap screws 25a. When the punch member is properly inserted in the base member, a continuous fiat planer surface is formed comprising the lower face of base element 25, the bottom of the punch member 30, and the lower face of the base element 24.

Preferably, cutting corners of the cutting face 31 of the punch member are cut at 15 degree angles (FIGS. 3, 4). When the punch is assembled and the die and base members are closed, the walls of the body 32 closely complement the opening formed in the mated insert sections 16 and 17 by the opposed slots 18. The punch member and the insert formed by insert sections '16 and 17, being comprised of tool steel, may be closely toleranced by conventional milling or grinding techniques.

The insert sections 16 and 17 and the cutting face 31 of the punch member 30 are easily removable merely by disassembly of the punching tool. The cutting face can be re-ground and the sections filed, ground or milled to sharpen them. If wear of the punch member or insert sections is too advanced for repair, any or all of these elements can be replaced inexpensively and the remaining punch components salvaged instead of being discarded.

Templates 36 comprises a fiat plate having a central circular aperture 37 and a pair of spaced transverse holes 38. The template is used to establish the location of the panel where the punch is to be made and may then be used in the punching operation as an element of the punch by positioning it on the upper surface of the die member 10.

A bolt 39 having a head 40 and a threaded shank 41 is adapted to be inserted through the aperture 37 in the template to extend through the opening 11 in the die member and through the hole formed by the opposed slots 18 when insert sections 16 and =17 are mated in the slot 18 of the die member 10. The shank 41 of the bolt 39 is threaded to engage a threaded hole 42 which extends through the punch member 30.

A thrust bearing 43 may be placed on the bolt with a face of the thrust bearing being against the lower part of the head 40 of the bolt 39. It is retained in such position either by a resilient fastener or ring 44 pressed onto the shank of the bolt above the threads and adjacent the thrust bearing 43 or by a simple O-ring tightly fitted around the shank of the bolt.

Pins 45 maintains the die member 10 in alignment with the base member 23. The pins are secured in the base member 23. A pair of pins are shown extending perpendicularly from the upper surface of the base element 24. The cross section of each pin 45 is such that it will slide through the hole formed by the semi-circular grooves 19 when the insert sections 16 and 17 are opposed, through the holes 12 in the die member 10 and through the holes 38 in the template 36.

In working near hot conduit boxes, it is important from a safety viewpoint that both the punch member and pins extend from the same member, leaving only the base member within the box and forcing the punched blank outside the box. If such were not the case, the extending pins and a dropped blank could touch a hot connection and short circuit it through the punch to the operator or complete undesirable circuits.

In FIG. 5, we have outlined the sequence of steps to be followed in using our punch to forman opening in a panel, such as usually covers an electrical switch. Step a shows the template 36 laid over a panel P. Holes corresponding to the template aperture 37 and holes 38 are first drilled in the panel.

The punch is then positioned on the panel P, as shown in step b. The base member holding the punch member 30 is mounted on one face of the panel by inserting the pins 45 through the smaller holes formed in the panel. Die member 10 including the insert sections 16 and 17 is next mounted on the pins in the opposite face of the panel by aligning the holes formed by the oppositely disposed insert grooves 19 with the pins and pushing the die member 10 toward the panel to engage the pins 45 with the holes 12 in the member 10. Finally, template 36 is placed over the pins 45.

Our punch may be so designed such that maximum metal thickness which can be punched is determinable at a glance merely by noting the position of the pins 45. In this connection, when a panel to be punched is placed between the die and base members and the template placed over the pins, the head of each pin must be flush with or extend above the upper face of the template .(FIGS. 3, 4). If the pins do not so extend, the panel is too thick and either the panel may be damaged in attempting to punch it and/ or the punch may be damaged in operation.

In FIG. 5b, the pins protrude through the template a short distance indicating that the panel P can be punched.

In step c, bolt 39 has been tightened and the base member 23 has been drawn toward the head 40 of the bolt. The punch member 30 has been forced through the panel P into the insert opening formed by slots 18 and into the die member 10, and the panel punched. Panel blank 46 has been punched and is retained above the punch member 30 in the opening =11 in the die member 10.

When the punching operation is completed, our tool is removed and the finish punched panel P appears as shown in step d of FIG. 5.

Our tool is useful on metal, plastic or composition materials provided they are thin enough to be accommodated between the punch and die members and can be shared cleanly without cracking or deteriorating under loading.

Having described a preferred embodiment of our invention, it will be understood that it may otherwise 'be included within the scope of the appended claims.

We claim: a

1. A tool for punching an opening in a panel in alignment with a central aperture therein between a pair of holes, one on either side of the aperture comprising:

(A) base and die members,

(a) each of said base and die members having a working surface and adapted to close toward and separate from the other and from a surface of a panel disposed therebetween;

(b) said die member having a pair of spaced holes corresponding to the pair of holes in the panel and in its working surface an opening larger than the opening to be punched by the tool and adapted for alignment with the central panel aperture;

(c) said base member having a pair of pins extending substantially normal to the working surfaces of the die member and slideably engageable with said spaced holes in the panel and said die member to maintain alignment between said base and die members during the punching of the panel;

(B) an insert removeably secured in the working surface of said die member and having,

(a) a pair of spaced holes corresponding to and adapted for alignment with the spaced holes in said panel;

(b) said holes being of sufficient size to slideably engage said pins;

(c) a central opening corresponding substantially to the opening to be punched in the panel and adapted for alignment with the opening in said die member and the central aperture in said panel;

(C) a punch member having a body and a cutting face carried by said base member and extending substantially parallel to said pins,

(a) the body of said punch member being removeably secured in said base member between said pins and adapted for alignment with said openings in said insert and said die member;

(b) the cutting face of said punch member adapted to be forced through said panel into said insert opening and said opening in said die member;

(c) the punch member having a threaded bore extending from its cutting face through its body and adapted for substantial alignment with the insert and said die member openings;

(D) a bolt means having a head and a threaded shank for closing against and separating the working surfaces of the die and base members from the panel,

(a) the bolt adapted to be extended through the openings in said die member and in the panel; and

(b) threaded into the bore of the punch member whereby when the bolt is tightened the die and base members are drawn together forcing the cutting face of the punch member into cutting engagement with the opening in the insert.

2. A tool as set forth in claim 1 wherein said insert comprises a pair of flat sections which are substantially identical, each of said sections having an edge characterized by:

(A) a spaced pair of semi-circular grooves extending transversely through said insert; and

(B) a central slot cut in the edge between said grooves, said insert being formed by joining the sections along said edge, the opposed slots forming an opening through said insert and the opposed grooves forming the holes through said insert with which the pins are adapted to slideably engage.

3. A tool as set forth in claim 1 wherein said base member comprises a pair of elements:

(A) at least one of said elements being a pin-carrying element and having an edge adapted for joining to the other element;

(B) the edge of said one element having a transverse slot formed therein; and

(C) the other element being adapted to close the slot to provide the opening in said base member.

4. A tool as set forth in claim 1 and wherein a thrust bearing is disposed on said bolt means adjacent and between said head and said die member for preventing fatigue of the bolt upon tightening of the punch member against the panel.

5. A toolas set forth in claim 4 wherein the bearing is held on the bolt with one face of the bearing adjacent the bolt head by a ring surrounding the bolt shank, a groove cut in the circumference of the shank adjacent the face of the bearing whereby the ring is held on the bolt and the thrust bearing positioned against the head of the bolt by snapping the ring in the groove.

6. A tool as set forth in claim 1 wherein the working surface of said die member includes a longitudinal slot in which the insert is disposed, the depth of the slot being substantially the width of the insert.

7. A tool as set forth in claim 1 wherein said base and die members are steel material and said punch member and insert are tool steel.

8. A tool as set forth in claim 1 wherein the cutting face of said punch member is rectangular and each edge is substantially of V-shaped configuration with the four corners of the rectangular face being the highest points on the face.

9. A tool as set forth in claim 8 wherein the lowest point of the longer parallel edges of the cutting face is deeper than the lowest point of the shorter edges of the face and the legs of each of the V-shaped edges extend at an angle of approximately 15 degrees outwardly from said lowest points.

References Cited UNITED STATES PATENTS 3,074,165 1/1963 Davis 30-358 3,255,526 6/1966 Molitor 30-360 3,269,011 8/1966 Herrstrum 30360 FOREIGN PATENTS 851,760 10/1939 France.

ROBERT C. RIORDON, Primary Examiner I. C. PETERS, Assistant Examiner

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