US2342867A - Pneumatic punch jig - Google Patents

Description

R. KENNEDY ET AL PNEUMATIC PUNCH JIG Feb. 29, 1944.

Filed June 28, 1943 //v VENTORS EARL. L. HILL Rm KENNEDY AGENT Patented Feb. 29, 1944 UNITED STATES PATENT OFFICE PNEUMATIC PUNCH J IG Roi Kennedy, Los Angcles, and Carl L. Hill, Burbank, Calif., assignors, by mesne assignments, to Lockheed Aircraft Corporation, a corporation of California Application June 28, 1943, Serial No. 492,546 I 14 Claims. (Cl. 164-94) 7 This invention relates to punching apparatus and relate more particularly to punching apparatus for punching openings in tough and resilient material.

This invention finds a specific application in the rapid punching of bolt and rivet holes in the quantity production of metal parts and components of variou forms and contours which must be interchangeably employed in the fabrication of airplane assemblies, the inventionnot being limited to this or any other specific use.

Heretofore, when series of openings were required in objects having complicated shapes and Where a high degree of accuracy and complete interchangeability of such parts was required, it was common practice to drill the openings. In performing this operation in tough resilient materials, such as stainless steel, and where small holes are required, the drill breakage due to toughness of the material and inexperienced or careless handling, is extremely high.. Also, a drill produces a burr on the lower side of the sheet material that must be removed before the part may be assembled, due to the scratching effect of the burr, and to provide a tight fit between the sheet and its adjoining member. In a drill jig adapted to perform this aforesaid operation, chips of the drilled material constantly hamper the operator, thus impeding the successive steps of the operation.

It is a general object of this invention to provide a practical, efiective and efficient means for locating and punching openings in metal sheets and the like.

Another object of this invention is to provide a jig and pneumatic punch means operable to punch openings in tough resilient materials with a minimum possibility of leaving burrs and without the breakage of parts. The device of the invention completely eliminates the drill breakage problem that Was heretofore an incident of the opening-forming operation and there is, little or no punch breakage.

Another object of the invention i to provide a tool of the character mentioned that is strong, tamper-proof and easy to employ.

Another object of the invention is to provide a pneumatic punch and jig combination that expedites the opening-forming operation and makes for greater safety by eliminating the use of the high-speed motor driven drill heretofore employed.

Another object of the invention is to provide a punch jig in which the slugs or scrap or scrap portions. are automatically cleared and cannot interfere With succeeding operations.

Another object of the invention isrto provide a combination of a jig of the character referred to above and an elfective pneumatic punch for use with the same.

Other objects and features of the invention will become apparent from the following detailed description. The typical preferred form of the invention is illustrated in the accompanying drawing in which:

Figure l is a perspective viewof the jig and punch of the invention.

Figure 2 is an enlarged fragmentary sectional view taken a indicated by line 22 on Figure 1.

Figure 3 is an enlarged fragmentary sectional View taken as indicated by line 3-3 on Figure l.

Figure 4 is a view similar to Figure 2 showing the punch in position for operation, and

' Figure 5 is a view similar to Figure lshowing the punch operated.

In the drawing the punch jig is indicated generally at Hi. The jig it comprises a lower plate I I, base block I2 secured to the lower plate and a top plate it. The base block I2 and the top plate I3 may be formed of metal, plastic or combinations of such suitable materials and are shaped so that the work sheet I4 may be engaged between them. In the particular case illustrated, the base block 12 presents a curved, convex upper surface, and the upper plate l3 has a correspondingly shaped under surface.

Bushing supporting members It are cast or otherwise fixed in the corner portions of the top plate l3 and each member has a socket l6 entering its lower end. A reduced vent opening I8 extends upwardly from each socket it to the atmosphere. 7 Locating bushings l9 are provided in the sockets it and are adapted to receive upwardly projecting portions of locating pins 20 carried by the lower plate H. The work sheet It has openings ii for receiving the pins 20 to be accurately locked thereby.

Means are provided to secure the top plate [3 to the lower plate ll so thatthe work sheet l4 maybe secured or clamped between the toppl te and the base block it. In the form of the invention illustrated, rods 23 are oastin the lower plate It adjacent its opposed ends and project upwardly from the plate to extend through openings 241 in. the top plate 13. -Wing nuts 22 are threaded on the rods iftoflehgage. with the upper surface of the top plate l3 and thus secure the assembly'together.

, Inaccordance .withthe invention, the top plate I3 is provided with one or more punch receiving bushings 25 located as required for the particular punching operation. In the construction illustrated, the bushings 25 are arranged in rows in spaced adjacent relation to the opposite ends of the top plate I3. The exteriors of the bushings 25 are ribbed or flanged and the bushings are received in openings 26 of the top plate I3 with substantial clearance. A low melting point metal 21 is poured or cast in the openings 26 around the bushings 25 to fix the bushings in the openings. It is preferred to employ a metal 21 which expands upon cooling.

The base block I2 is provided with bushings 28 similar to the above described bushings 25. The upper surface portion of the base block I2 is provided with sockets 9 aligned with the sockets or openings 26. The bushings 28 are cast in the sockets 9 by a low melting point metal 8 that expands upon cooling. The bushings 28 are flanged or ribbed to be effectively retained in the metal 8. The bushings 25 and 28 secured in the manner described may be very accurately aligned. The inner ends of the bushings 25 are curved or shaped to conform to the inner surface of the top plate I3 and the upper ends of the bushings 28 are shaped to have the same curvature as the top surface of the base block I2.

The invention provides the top plate I3 with a stripper plate 29 of a selected hard steel or the like. The stripper plate 29 is curved to conform to the lower surface of the top plate I3 and to conform to the work sheet I4. Spaced screws 30 may serve to secure the stripper plate 29 to the top plate I3. Openings 42 are provided in the stripper plate 29 in alignment with the openings 32 of the bushings 25 and the openings 44 of the bushings 28. The openings 42 of the stripper plate I3 are smaller in diameter than the openings 32 and are of substantially the same diameter as the upper portions of the openings 44.

Means is provided for clearing the scrap portions or slugs from the jigs. The under side of the base block I2 is provided with a longitudinal chamber 46 of substantial cross section. The openings 44 in the bushings 28 are counter-bored from their lower ends and communicate with openings 45 in the base block I2. The openings 45 extend downwardly to communicate with the chamber 46. It will be seen that the slugs 46 from the work sheet I4 are free to fall through the openings 44 and 45 into the scrap chamber 46.

The pneumatic punch of the invention includes a conventional pneumatic gun or single shot riveter indicated at 40. The punch further includes a mandrel or adapter 34 carried by the riveter 49 to be actuated thereby. A central opening 3| enters the lower end of the adapter 34 and re ceives a punch 33. The punch 33 may be fixed to the adapter 34 by a pin 35 engaged in openings in the adapter and punch, and having an end portion 35 engaged about the exterior of the adapter. The punch 33 extends downwardly beyond the adapter 34 and is provided at its lower end with a cutting portion M of reduced diameter. The openings 32 of the bushings 25 are adapted to slidably receive the punch 33 and the openings 42 of the stripper plate 29 are proportioned to accurately receive the cutting part 4|.

The punch further includes a stripper spring 36. The spring 36 is a coiled compression spring surrounding the lower portion of the adapter 34 and partially surrounding the punch 33. The upper end of the spring 36 bears against a shoulder 3'! on the adapter 34 and the upper convolu tion of the spring may be attached to the adapter by a ring 53. The lower end of the spring 36 is adapted to engage against the outer ends of the bushings 25 so that the spring is compressed upon actuation of the punch.

' In use the base block I2, the top plate I3 and the stripper plate 29 are formed to the contour of the work sheets I4 and the bushings 25 and 23 are secured in the base block and top plate I3 at the required locations. When a sheet I4 is to be punched it is engaged on the base block I2 so that it is located by the pins 29 and the top plate I3 is engaged over the sheet so that the stripper plate 29 bears against the sheet. The assembly is clamped together by means of the wing nuts 32. The sheet I4 is then ready for punching. The punching operation is carried out by entering the punch 33 in the several bushings 25 and operating the pneumatic gun 40. Upon actuation of the gun 49 the cutting portion M of the punch, punches an opening in the sheet I4. The stripper plate 29 prevents the sheet I4 from being deformed at the punching point and allows the cutting portion 4| to pass through without forming a burr on the work The spring 36 assures an effective stripping of the punch. The slugs 43 drop away from the bushings 25 and 28 leaving the jig clean, and the slugs cannot remain to cause mis-alignment of the parts.

It is to be understood that the base block I2, the top plate I3 and the stripper plate 29 may be formed to the contour of any given work piece and that the bushings 25 and 28 may be located as required.

Having described only a typical form of the invention We do not wish to be limited to the specific details herein set forth, but wish to reserve to ourselves any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

We claim:

1. A jig for use in forming openings in work sheets or a given contour comprising a base having a surface for conforming to a work sheet, an outer part, a stripper plate on the outer part shaped to conform to the opposite surface of the work sheet, sets of bushings in the base and outer part, the bushings of each set having aligned openings, the stripper plate having openings aligned with the openings of the bushings, the openings being adapted to receive a tool for forming openings in the work sheet, and means securing the outer part to the base so that the work sheet is held between the base and stripper plate.

2. A jig for use in forming openings in work sheets of a given contour comprising two ele-- ments having opposing surfaces shaped to conform to the contour of the work sheets, spaced pairs of aligned openings in the elements, bushings, material cast in said openings to secure the bushings therein, a stripper plate on said surface having openings aligned with the bushings, the bushings and openings of the stripper plate being adapted to receive a punch for punching openings in the work sheet, and means for clamping the elements together to secure the work sheet therebetw-een.

3. Punching apparatus comprising two elements between which the work is to be engaged, the elements having aligned openings, a stripper plate on one element having an opening aligned with and of smaller cross sectional dimensions than the first named opening in that element,

and apunch adapted to be passed into said first named opening ,and operated; through the opening in the plate to punch an opening in the work. 4.,Apparatus for punching openings in work sheets including a pair of opposing parts, a stripper plate on the inner side of one of said parts, said opposing parts and stripper plate being shaped to conform to a work sheet so that the sheet may be engaged between one of said opposing parts and the plate, said opposing parts and plate having one or more sets of aligned openings, the openings in the plate being of smaller cross sectional dimensions than the openings in said part which carries the stripper plate and a pneumatic punch having a punch element operable in said openings for punching openings in the work sheet.

5. Apparatus for punching openings in work sheets including a pair of opposing parts, a stripper plate on the inner side of one of said parts, said opposing parts and stripper plate being shaped to conform to a work sheet so that the sheet may be engaged between one of said opposing parts and the plate, said opposing parts and plate having one or more sets of aligned openings, the openings in the plate being smaller than the openings in said opposing parts, and a pneumatically operated punch adapted to be entered into the openings in one of said opposing parts and operated through the openings in the plate to punch openings in the work sheet.

6. Apparatus for punching openings in contoured work sheets including a base plate, an outer plate and a stripper plate on the inner side of the outer plate, said plates being contoured to conform to the work sheet so that the work sheet may be arranged between the base plate and the stripper plate, said plates having aligned openings, the openings in the stripper plate being smaller than the openings in the other plates, and a punch operable in the aligned openings to punch openings in the work sheet.

7. Apparatus for punching openings in contoured work sheets including a base plate, an outer plate and a stripper plate on the inner side of the outer plate, said plates being contoured to conform to the work sheet so that the work sheet may be arranged between the base plate and the stripper plate, means for locating the work sheet in a given position, said plates having aligned openings, the openings in the stripper plate being smaller than the openings in the other plates, and a punch operable in the aligned openings to punch openings in the work sheet.

8. Apparatus for punching openings in contoured work sheets including a base plate, an outer plate and a stripper plate on the inner side of the outer plate, said plates being contoured to conform to the work sheet so that the work sheet may be arranged between the base plate and the stripper plate, bushings set in the base plate and outer plate, the bushings and stripper plate having aligned openings, and a punch adapted to be moved from one set of aligned openings to the other and having a punch element operable in the aligned openings to punch openings in the work sheet.

9. Apparatus for punching openings in contoured work sheets including a base plate, an outer plate and a stripper plate on the inner side of the outer plate, said plates being contoured to conform to the work sheet so that the work sheet may be arranged between the base plate and the stripper plate, bushings fixed in the base plate and outer plate, the bushings and stripper face, a stripper plate plate having aligned openings, and a punch adapted to be moved from one set of aligned openings to the other and including a punch element adapted to be inserted in the alignedopenings and operated therein to punch openings in the work sheet, ,the base plate having openings for receiving the material punched from the work sheet.

10. In punching apparatus, a jig comprising a base block having an outer surface, an outer plate having a correspondingly shaped inner surface, a stripper plate secured to and conforming to said inner surface, bushings secured in the base block and the outer plate, the bushings and stripper plate having aligned openings, means for 10- eating a work sheet in a definite position between the base block and the stripper plate, and a punch device operable in said openings to punch openings in the work sheet including a power operated mandrel, a punch member on the mandrel insertable into said aligned openings and a resilient stripper around the mandrel adapted to be compressed against the bushings on the outer plate.

11. In punching apparatus, a jig comprising a base block having an outer surface, an outer plate having a correspondingly shaped inner sursecured to and conforming to said inner surface, bushings secured in the base block and the outer plate, the bushings and stripper plate having aligned openings, the openings in the bushings of the outer plate being larger in diameter than the other openings, means for locating a work sheet between base block and the stripper plate, the base block surface and the stripper plate being shaped to the contour of the work sheet, means for clamping the work sheet between the base block and the stripper plate, and a punch device successively insertable into the bushings of the outer plate and operable in said openings to punch openings in the work sheet.

12. A jig for use in punching openings in contoured sheets including a base, an outer part to be arranged over the base, a stripper plate on the under side of said part, the plate and upper side of the base being shaped to conform to a sheet so that a sheet may be engaged between them, spaced pairs of aligned bushings fixed in the base and outer part, openings in the stripper plate aligned with the bushings, the bushings and openings being adapted to receive a punch for forming openings in the sheet, and means for clamping the sheet between the base and stripper plate, the base having openings leading from its bushings to receive the slugs punched from the sheet.

13. A jig for use in punching openings in contoured sheets including a base, an outer part to be arranged over the base, a stripper plate on the under side of said part, the plate and upper side of the base being shaped to conform to a sheet so that a sheet may be engaged between them, spaced pairs of aligned bushings fixed in the base and outer part, openings in the stripper plate aligned with the bushings, the bushings and openings being adapted to receive a punch for forming openings in the sheet, and means for clamping the sheet between the base and stripper plate, the base having openings leading from its bushings to receive the slugs punched from the sheet, and a receiver chamber communicating with the last named openings.

14. Apparatus for punching openings in work sheets including a pair of opposing parts, a stripper plate on the inner side of one of said parts, said opposing parts and stripper plate being shaped to conform to a work sheet so that the sheet may be engaged between one of said opposing parts and the plate, said opposing parts and plate having one or more sets of aligned openings, and a pneumatic punch operable in said openings for punching openings in the work sheet,

the punch including a pneumatically operated mandrel, a punch member carried by the mandrel and insertable in said aligned openings, and a stripper spring means on the mandrel compressed against one of said parts upon actuation of the mandrel.

ROI KENNEDY.

CARL L. HILL.

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