US 3317407 A
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' M y 1967 J. KRATZMEYERY ETAL 3,317,407
METHOD OF MAKING A PUNCH BLOCK ASSEMBLAGE Filed Jan. 14, 1964 IO 2! 2O INVENTORS JOHN J. KRATZMEYER ROBERT J. MIANOWSKI BYIKQ L ATTO .NEY
United States Patent 6 3,317,407 METHOD OF MAKING A PUNCH BLOCK ASSEMBLAGE John J. Kratzmeyer, Des Plaines, and Robert J. Mianowski, Chicago, Ill., assiguors to Teletype Corporation,
Skokie, Ill., a corporation of Delaware Filed Jan. 14, 1964, Ser. No. 337,641 5 Claims. (Cl. 204-6) This invention relates to punch block assemblages for use with selectively-operated punches and to the method of manufacturing such punch block assemblages.
Perforators for use in teletypewriter equipment typi cally employs a punch block assemblage of the type depicted in Patent No. 2,308,543, issued to A.H. Reiber on Jan. 19, 1943, to make intelligence-representing perforations in a tape in permutation code combinations of holes. Since the perforations represent intelligence, the punch pins in such an assemblage must respond quickly and accurately so as faithfully to reproduce a representation of the intelligence fed to the perforator. Such punch pin response necessarily requires that the method of manufacture used to produce the punch pin assemblage meet very exacting manufacturing requirements. The
principal difficulty involved in the manufacture of such,
a punch block assemblage is encountered in the forming and locating of the apertures which guide and retain the punch pins. Since the punch pin is guided by two apertures and enters a third aperture located in a die plate during the punching of a hole, these three apertures must be accurately made and positioned so that no binding of the punch pin will occur during its punching movement and so that the punch pin will enter the aperture in the die plate producing a clean, sharply-sheared hole accurately located on the tape without striking the die plate near the wall of the aperture. Previously, such punch assemblages were manufactured by securing a guide plate above and below a generally inverted, U- shaped casting. Holes were drilled in the upper and lower guide plates and in the die plate. The upper guide plate and die plate were then lapped to size in pairs. After lapping, the upper guide plate and die plate had to be kept in pairs. When the lower guide plate and the paired upper guide plate and die plate were assembled, some hand adjustment was usually necessary to allow free travel of the punch pins. Obviously, such a customized method of manufacture was time consuming, tedious and extremely expensive.
Two methods suggested for improving the manufacture of punch block assemblages are contained in Patent No. 3,083,604 issued to A. L. Ferren on Apr. 2, 1963, wherein punch pins coated with lubricant are inserted into a punch block and die plate; and a casting resin is poured into place to provide a punch pin retaining and guiding means; and in the copending application of E. D. Hennigan, Ser. No. 328,214, filed Dec. 5, 1963, wherein punch pin guide sleeves are custom-positioned and held in place by a casting material.
It is an object of the present invention to reduce the cost of manufacturing punch block assemblages for perforators while retaining a high degree of quality in the assemblage produced.
Another object of this invention is to provide a simple and inexpensive punch block assemblage and a method of manufacturing it that does not require a high degree of skill.
In acordance with the preferred embodiment of the invention, a punch block assemblage is provided wherein the punch pin is slidable in a guiding sleeve that is of a slightly larger inside diameter than the outside diameter 3,317,407 Patented May 2, 1967 ice of the pin. The punch block assemblage is made by forming punch pin guide apertures in a punch block; forming those apertures at the final punch pin guide location in the punch block slightly larger than the diameter of the punch pin to be used with the block, inserting a mandrel through the guide apertures in the punch block and into punch pin receiving apertures in an attached die plate; thus, aligning each mandrel to the ideal location for the punch pins which are later substituted for the mandrels. Thereafter, a coating of metal is electroformed around the mandrels and onto those areas of the punch block which are adjacent the apertures previously formed therein. The mandrels are then removed and the punch pins are substituted in their place, resulting in a finished punch block asemblage.
A more complete understanding of the invention may be obtained from the following detailed description when considered in conjunction with the accompanying drawings wherein:
FIG. 1 is a perspective view of the completed punch block assemblage;
FIG. 2 is a fragmentary perspective view of the punch block with a die plate attached to it, the mandrels and punch pin guiding sleeves being omitted from this view;
FIG. 3 is an enlarged cross-sectional view taken along line 33 in FIG. 1 in the direction of the arrows showing a mandrel in place with the guiding sleeve formed around the exposed portion of the mandrel and fixed to those portions of the block adjacent the apertures in the block; and
FIG. 4 is an exaggerated enlarged, fragmentary, crosssectional view of the punch block assemblage taken along line 44 in FIG. 3 in the direction of the arrows showing the finished plating but without the mandrels or punch pins in place.
Referring now to the drawings wherein like reference numbers designate the same parts throughout the several views particular reference being had to FIG. 1 wherein there is shown a punch block assemblage consisting of a punch block comprising a right side 6, a left side 7, a top 8, and a bottom 9; and a die plate 10 attached to the punch block with screws 16. Punch pins 17 are inserted through guide apertures in the bottom 9 of the punch block and up through guiding sleeves 19 into die apertures 20 in the die plate 10.
The positioning of the guide means for the punch pinis very critical in the manufacture of a block; and the punch pin guiding sleeves 19 which are tubes of any suit able material formed integrally with the top 8 and bottom 9 of the punch block, are located by die apertures 20 in the die plate 10. The actual movement of the punch pin during the punching operation is within the punch pin guiding sleeve 19. To provide adequate clearance, the guiding sleeve must have an inside diameter slightly larger than the punch pin; but too large an inside diameter, that is, too much clearance, would allow too much lateral movement of the pin and result in a poorly constructed punch assemblage.
The punch pins 17 are slidable along their axes within the punch block assemblage, and die plate 10 has a recess 21 in its bottom surface, adjacent the top 8 of the punch block, which is deep enough to provide a gap therein between the die plate and top 8 of the punch block to provide room for insertion of paper tape to be perforated. The punch pins in their normal mode of operation are moved from a position below the upper surface 27 of the top 8 of the punch block upwardly through the tape in recess 21 and into die apertures 20, shearing holes in the paper tape in the shape of the punch pins 17 and their mating die apertures 20. The punch pins 17 are then retracted downwardly and the tape is advanced a predetermined increment for punching another group of holes.
The inside diameter of the punch pin guiding sleeve 19 is preferably .OOOZ-inch larger than the normal diameter of the punch pin plus maximum tolerance. This provides a nominal radial clearance for the punch pin of at least .0001-inch. These punch pin guiding sleeves 19 are formed in place by a method called electroforrning.
In the preferred, electroforming, method of constructing a punch block assemblage containing sleeves for guiding the punch pins, guide apertures 18 (FIG. 2), of a suitable dimension to guide the punch pins 17, are formed in the bottom 9 of a cast iron punch block, and clearance apertures 22 are formed in the top 8 of the punch block which apertures 22 are larger in diameter than the outside diameter of the punch pin 17. In the preferred electroforming process, silver-coated, steel mandrels 28 are inserted through apertures 18, 22, and 20. These mandrels are .0002-inch larger in diameter than the diameter of the punch pins 17. This is the desired inside diameter of the punch pin guiding sleeve 19. The punch block, the die plate, and the mandrels are all masked except the exposed portions 29 of the punch block sides 6 and 7, the punch block top and bottom 8 and 9, and those portions of the mandrels 28 extending between apertures 18 and apertures 22. A casing of hard nickel, approximately .OIS-inch thick, is then electroplated onto the unmasked portions of the cast iron block and the silver-coated mandrels in an electroplating bath which has been treated in a well-known manner to deposit a plating that contains an initial compressive stress. This causes the plating to tend to expand away from the external surfaces of the silver-coated mandrels and expand into tighter contact with the internal surfaces of the exposed portions 29 of sides 6 and 7 and top and bottom 8 and 9 of the punch block. The silver-coating of the mandrels facilitates removal of the mandrel from the formed tube, whereas the plated casing forms a mechanical bond to the rough unsilvered, exposed portions 2 9 of the cast iron punch block.
Clearance apertures 22 are sufficiently larger than the mandrels or punch pins to provide no guiding for the punch pin but merely to prevent significant migration of ions in the plating bath into recess 21. Guiding of the punch pin occurs in aperture 18 and all along the length of the inside of guiding sleeve 19.
In manufacturing a punch block according to the prior art methods, the exact alignment of the three apertures to permit rapid movement of a punch pin from the two apertures in the punch block into the die apertures was a major expense. It can be seen that in the method de scribed herein, the inner surface of guiding sleeve 19 adjacent oversize aperture 22 consists of the hard nickel plating which is located in its optimum guiding position by forming the guiding sleeve 19 around the mandrel 28 While it is correctly located by apertures 18 and 20. Each guiding sleeve 19 is thus custom-positioned by its mandrel 28 to guide its associated punch pin 17 into its associated die aperture 20. This obviates the time consuming and expensive requirement of lapping punch pin guide apertures 22 and die apertures 20 by pairs so that the critical apertures will be aligned. After the mandrel has been withdrawn, the punch pins, which will be a permanent part of the punch block assemblage, are inserted in their place.
Although only one embodiment of the invention is shown in the drawings and described in the foregoing specification, it will be understood that invention is not limited to the specific embodiment described, but is capable of modification and rearrangement and substitution of parts and elements without departing from the spirit of the invention.
What is claimed is:
1. The method of making a punch block assemblage 4 including a punch block and attached die plate having punch-receiving aperture which comprises the steps of:
forming an aperture of predetermined size in the punch block;
attaching the die plate to the punch block with its aperture in alignment with the punch-receiving aperture in the die plate;
inserting a mandrel into the aperture in the punch block and through the aperture in the die plate; masking all areas of the punch block, die plate, and
mandrel except areas of the punch block and mandrel between the portion of the punch block in which the aperture is formed and the die plate;
electroplating metal onto the unmasked areas of the punch block and around the mandrel;
removing the mandrel; and
inserting a punch pin in place of the mandrel.
2. The method of making a punch block assemblage including a die plate and a punch block, which comprises the steps of:
forming a punch pin receiving aperture in the die plate;
forming an aperture in the punch block;
securing the die plate to the punch block with the apertures therein aligned;
inserting a mandrel through the punch block aperture and into the die block aperture;
electroplating metal around the mandrel and onto the punch block in areas between the portion of the punch block in which the aperture is formed and the die plate;
removing the mandrel; and
inserting a punch pin in place of the mandrel.
3. The method of making a punch block assemblage including a punch block and a die plate having a punchreceiving aperture, which comprises the steps of:
forming an aperture of predetermined size in the punch block;
attaching the die plate to the punch block with its aperture in alignment with the punch-receiving aperture in the die plate; inserting a mandrel into the aperture in the punch block and through the aperture in the die plate; electroplating metal around the mandrel and onto the punch block in areas between the portion of the punch block in which the aperture is formed and the die plate which electroplated metal will adhere to the punch block but not to the mandrel; and replacing the mandrel with a punch pin. 4. The method of making a punch block assemblage having two punch pin guiding areas for guiding a punch pin toward a punch aperture in an associated die plate comprising:
forming a punch pin guiding aperture in the one of said areas which is remote from the die plate, of a size to accept a punch pin in sliding relation thereto;
forming a clearance aperture in the area of the punch block which aperture is closely adjacent the die plate, which aperture is of a diameter substantially larger than the outside diameter of a punch pin to be used in the assemblage;
attaching the die plate to the punch block with its punch aperture in alignment with the punch pin guiding aperture in the punch block;
inserting a mandrel of substantially the same outside diameter as the punch pin to be used in the assemblage through the remote aperture, the closely adjacent aperture, and the die aperture in the die plate; and
electroplating metal around the mandrel and onto the punch block in areas between the portion of the punch block in which the aperture is formed and the die plate.
5. A method of making a punch block assemblage including a punch block having an aperture therein and with an attached die plate having a punch-receiving aperture approximately aligned with the aperture in the punch block which comprises the steps of:
inserting a mandrel which may be a punch pin into the aperture in the punch block and into the punchreceiving aperture in the die plate; masking all areas of the punch block, die plate, and
mandrel except areas of the punch block and mandrel between the portion of the punch block in which the aperture is formed and the die plate; and
References Cited by the Examiner UNITED STATES PATENTS 2,893,489 7/1959 Thompson 83685 3,137,193 6/1964 Whistler 83-685 3,141,357 7/1964 Schultink 76-107 3,145,586 8/1964 Brearley 76-107 JOHN H. MACK, Primary Examiner.
electroplating metal onto the unmasked areas of the 10 WILLIAM DYER Examiner punch block and'around the mandrel.
J. L. SEITCHIK, Assistant Examiner.