US2604742A

US2604742A - Punch element and method of making same

Info

Publication number: US2604742A
Application number: US740917A
Authority: US
Inventors: John F Kopczynski
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-04-11
Filing date: 1947-04-11
Publication date: 1952-07-29
Anticipated expiration: 1969-07-29

Description

July 29, 1952 J; F. KOPCZYNSK] 2,604,742

PUNCH ELEMENT AND METHOD OF MAKING SAME Filed April 11. 1947 2 SHEETSSHEET 1 LAW Offering 5'.

y 29, 1952 J. F. KOPCZYNSKI 2,604,742

PUNCH ELEMENT AND METHOD OF MAKING SAME Filed April 11, 1947 2 SHEETSSHEET 2 22 FIG. 5

24 20 FIG. 4

, xv M 28 9 FIG. 6

' IN VEN TOR.

Patented July 29, 1952 John-F. Kansas, meat; N. Y. application April "11, 1947, sesame. 740.911

This invention relates to tools, andparticular-ly to punches for punching holes or ape-rture's sheets.

In punching apparatus the punch element commonly has a reduced end portion or stem which does the punching, and an intermediate or Junetion part connecting the main body-portion with the reduced end portion or piercing end. This intermediate part usually is tapered or increases progressively in cross sectional area through a plurality of stages from the reduced end to the body portion.

It is highly desirable that the ground grain on the sides of the punch element extend lengthwise in order to provide a clean, punched aperture and lon life for the punch element.

An object of the invention is to'provide an improved punch element with a ground surface on the side of the punching or piercing end, in which the ground grain runs generally parallel to the longitudinal axis of the piercing end; with which the picking up of small particles of stock by the reduced punch element end will be reduced to a minimum; with which the tendency of the punch element to crack and break in use will be 'reduced; with which a more perfect blending be tween the reduced end and tapered portion may be obtained; with which heating of the punch during grinding is reduced; and which will be relatively simple, practical, inexpensive, and of long life. 7

Another object is to provide an improved and simple method of grindingthe sides of a punch element to reduce it accurately to the desired size,

and to form thereon a ground grain running parallel to the longitudinal axis of the punching end of the punch element; and with which one may obtain a more perfect blending or merging of the punching end into the tapered section connecting the punching end to the body of the punch element.

Other objects and advantages will be apparent from the following description of one example of the invention, and the novel features will be particularly pointed out hereinafter in connection with the appended claims.

This invention is a continuation, iln part, of copending application Serial No. "673,713 filed May 31, 1946.

In the accompanying drawing:

Fig. 1 is a side elevation of an apparatus constructed in accordance with this invention-for grinding the sides of the piercing endsbf. punches in a manner to have the ground graineiitending generally lengthwise of the punch j I col-aims. (o1. 51- 2s9) Fig. 2 is a plan of the Same;

Fig. 3 is a diagram illustrating, on an enlarged scale, the principle involved in grinding the punch element; V

Fig. 4 is an end elevation of the apparatus shown in Figs. 1 and 2;

' Fig. 5 is a sectional elevation of apart of the same, the section being taken approximately along the line 5-5 of Fig. 1; and

Fig. 6 is a sectional elevation of another part of the same, the section being taken approximate ly along the line 66 of Fig. 4. v

In the illustrated embodiment of the invention and referring first to Fig. 3, the punch element I is provided with a body part 2 bywhich it may be anchored in a movable member for a punching operation, and at the opposite end is a piercing shank or end 3 or reduced cross-sectional area, and with its side surface a surface of revolution such as a cylindrical shape. Between these two portions 2 and 3 is an intermediate part 4 "which is frusto-conical or tapered, with its larger base merging into the body part 2, and its smaller or convergent end merging into the cylindrical, piercing end 3. The small end of the tapered part '4 merges into the piercing end 3 through a concave, arcuate surface 5 having a small radius of curvature in transverse cross section. The periphery of the grinding or abrasive wheel is shown diagrammatically by the circle 6 in Fig. 3, and the wheel is rotated about an axis 1 such as in a clockwise direction in Fig. 3.

While the grinding wheel 6 is rotated about axis I in this manner, it is brought from the position A in Fig. 3 into contact with the side of the piercing end 3 of the punch element, while the punch element is being rotated about the longitudinal axis of the piercing end 3. The punch element is rotated about this longitudinal axis, shown by the dot and dash line E-E in Fig. 3, and while so rotating at a selected speed, the grinding wheel 6 is moved slowly along and in contact with the side of the piercing end 3 in a direction parallel to axis E-E, such as along the line"G--G, through the position B to the position C; which determines the length of the piercing end.

The-grinding wheel ii rotates at a substantially greater speed than the speed of rotation of the punch element. There should be a very sub stantial excess of speed "of the grinding wheel 6 over that of the punching element I, in order that the ground grain will run lengthwise of the piercingend 3. For example, excellent results have been obtained when the punch element I rotates at about 145 R. P. M. and when at the same time the grinding wheel 6 rotates about its axis 1 at about 55,000 R. P. M. Unless the speed of rotation of the wheel 6 is very substantially greater than the speed of rotation of the punch element, the best results will not .be obtained, and the speed of rotation of the grinding wheel should preferably be above at least ten times the speed of rotation of the punch element.

The movement of the grinding wheel 6 along the side of the punch element I should be relatively slow, so that the piercing end 3 of the punch element may be brought to the desired size, and when the wheel 6 reaches the C position in Fig. 3, its movement endwise of the punch element is stopped momentarily and then given a movement along the line F-F, instead of further along the line GG which it followed when grinding the side of the punch end 3. Thus from the C position the grinding wheel 8 moves with its axis along the line F-F past the position D until it leaves the punch element beyond the large end of the tapered part 4.

One mechanism for performing such a grinding operation, and which has been found to be very satisfactory, is illustrated schematically in Figs. 1, 2, 4, 5 and 6. Referring now to Figs. 1, 2 and 4 the grinder includes a base 8 having an upright standard 9. A moving table In is mounted on the upper end of the post or upright standard 9 and it carries a head stock H which may be shifted endwise on the table through manipulation of a screw mechanism operated by a hand wheel l2. Table I is moved endwise on standard 9 byrotation of wheel Illa. Wheel Illa operates a pinion (not shown) that drives a rack on the bottom of table H]. The head stock ll carries spaced bearings [3 which rotatably mount a spindle I4, and the latter has fixed thereon between the bearings l3, a driving pulley I around which passes a belt I0 that, in turn, is driven by a motor (not shown) or other source of power. The belt It thus rotates the spindle l4 about its longitudinal axis.

One end of the spindle l4 carries a face plate ll, which is similar. to the face plate of a lathe, and this face plate, in turn, carries an adapter l8, which, in turn, carries removable bushings IS. The body part2 of a punch element is removably mounted axially in the adapter l8, so that the longitudinal axis E-E of the punch element is coincident with the axis of rotation of the spindle I4, in the same manner that a rod to be turned is mounted and removably held in the chuck or collet of a turning lathe. Standard 9 has a pair of parallel, rearwardly extending arms 28 (see Figs. 4 and 6) which slidingly mount a platform 29 disposed above the arms 28 and which extends forwardly over the table 10. This mounting is similar to that commonly employed on machine tools, and has V-shaped ways or grooves in which are slidingly mounted V- shaped edges of platform 29. A lug 30 depends from platform 29 between arms 28, and a forwardly and rearwardly extending screw 3 I, which is parallel to the v-shaped ways, is threaded through the lug 30 and rotatably supported on standard 9. A hand wheel 2| fixed on the forward end of screw 3| enables one to rotate the screw in both directions and move the platform forwardly and rearwardly, which is cross wise of the direction of travel of table It]. On platform 29 is fixedly mounted a pedestal 20.

On the pedestal is mounted a supplemental moving table 22 which is set at an acute angle to the longitudinal axis of the spindle M or to the length of the table [0, such as at the desired angle of divergence of the surface of the tapered part 4 of the punch element from the axis EE. This angle is preferably made about 20 but the angle may be varied as desired. This moving table 22 is mounted on opposed V-grooves 32 of pedestal 20 to move lengthwise of itself on the pedestal 20 by a mechanism including a screw 23 rotatably mounted on table 22 and threaded through a lug on the rear end of pedestal 20. The screw 23 is operated by a hand wheel 24, in the same manner that the tool holder of a lathe is mounted for movement across the table of a lathe. The moving table 22 carries an arm 25 which extends toward the axis of rotation of the spindle I4, extended.

Mounted on the free end of the arm 25 is a suitable motor 26 with a depending spindle 2i driven thereby. This spindle 21 carries at its lower end the grinding wheel 6, shown diagrammatically on a large scale in Fig. 3. With the spindle 14 operating, say at a speed of about R. P. M. in a clockwise direction, and the grinding wheel 6 operating, say at about 55,000 R. P. M., the grinding wheel 6 may be relatively shifted lengthwise and slowly along the side of the piercing end 3 of the punch element, at first along the axis GG from the position A to the position 0. This relative movement in the illustrated embodiment is caused by operation of hand wheel l0a or l2 to shift the head stock and punch element past the grinding wheel and then with the head stock ll stopped against further longitudinal movement in a direction along the table [0, which may be determined by a suitable, adjustable stop, the hand wheel 24 may be operated to shift the grinding wheel 6 along a divergent path represented by the line F-F, during which the grinding wheel 6 moves from position C through-position D beyond the end of the tapered part 4. With such an arrangement the convex, arcuate fillet 5 will have a radius of curvature in transverse cross section corresponding to the radius of the grinding wheel 6. It provides a gradual transition between the cylindrical part of the piercing end 3 and the smaller end. of the tapered part 4. Because of the much greater speed of rotation of the grinding wheel 6 about its axis, than the relatively slower speed of rotation of the punch element, the ground grain on the side of the punch element will be largely lengthwise of the piercing end of the punch element.

Heretofore where the ground grain has run peripherally of the piercing end, such transverse grain has acted somewhat as a file and tended to pick up small pieces of stock out from the blank being pierced, and to bind in the blank and female die. This causes an unsatisfactory aperture in the blank that is pierced, and it causes an undue wear on the piercing end of the punch. The transversely ground grain also weakens the piercing end so that it is more apt to fracture along such grain than when the ground grain runs lengthwise.

It is believed that the operation of the device, and the manner of grinding, will be clear from the foregoing description. It will be understood that various changes in the details, materials and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled inthe art within the principle andscope of the invention, as expressed in the appended claims.

I claim:

1. The method of grinding the punching stem and adjoining tapered portion of a punch element of a punch and die unit to form, on the peripheral wall of said stem, a ground grain running in directions approximately parallel to the axis of said stem, which comprises mounting said element for rotation on the axis of said stem, mounting a grinding wheel with its axis of rotation crosswise of and ofiset from said stem axis of rotation with its periphery engaging said element, causing relative movement of said grinding Wheel, while it is rotating on its axis, bodily in a direction parallel to said stem axis, with the periphery of the wheel in contact with said stem and at the contact zone moving in a direction lengthwise of the stem, until said wheel reaches said tapered portion, and then parallel to and in contact with said tapered section along that section and rotating said grinding wheel at not less than about 30 times the speed of rotation of said element.

2. A punch element for a punch and die unit of the type having a body part, a piercing end of reduced and circular cross section, and an intermediate tapered part connecting said body part and piercing end, said connection to said end being through a concave, arcuate surface, said element having a ground grain on the side face of its piercing end running in a direction approximately parallel to the longitudinal axis of said end from the end face of the piercing end to the intermediate tapered part, and then lengthwise along the concave surface.

3. The method of grinding the piercing end of a punching element of a punch and die unit to form on the side of said end, a ground grain running in directions approximately lengthwise of said element, which comprises mounting said element for rotation about the longitudinal axis of said end, mounting a grinding wheel for rotation about an axis crosswise of and offset from said piercing end axis, with its periphery engaging the element rotating said element about said longitudinal axis at a selected speed, rotating said wheel about its said axis at a speed in excess of ten times greater than said selected speed, bringing said rotating wheel into contact with the side of said end, and then causing relative movement between said rotating wheel and said element in a direction lengthwise of said rotating end.

4. The method of grinding the piercing end of a punching element of cooperative punch and die parts to form on the side of said end a ground grain running in directions approximately lengthof at least about thirty times greater than said selected speed, bringing said rotating wheel into contact with the side of said end, then causing relative movement between said rotating wheel and said element in a direction'lengthwise of said rotating end, for a substantial distance while maintaining grinding contact of said wheel and element, and then progressively along lengthwise said element but diverging progressively from said longitudinal axis of said end, while maintaining grinding contact between said wheel and element.

5. A piercing punch element of a punch and die unit for punching a disc from a sheet blank, which comprises a metal body having at one end a cylindrical punching stem, a larger diameter shank portion at the other end by which said body can be mounted for endwise reciprocation, and an intermediate, tapered, frustoconical portion connecting said shank portion and said punching stem, said tapered portion merging into said punching stem through a concave, arcuate surface, the side surface of said punching stem and of said arcuate surface having a ground surface, with the ground grain of said surface extending in a direction generally lengthwise of said body.

6. A tool comprising a body portion, a convergingly tapered portion on one end of the body portion, and a punching end portion of uniform cross sectional area along its length, forming an extension of the smaller end of said tapered portion, said end portion and said tapered portion joining in a concave curve, said punching end portion having a ground peripheral surface with the ground grain of that surface running in a direction lengthwise of said punching end and tapered portions and up the smaller end of the tapered portion.

JOHN F. KOPCZYNSKI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 97,664 Marsh Dec. 7, 1869 744,340 Heald Nov. 17, 1903 800,443 Horton Sept. 26, 1905 1,273,016 Ward July 16, 1918 1,377,481 Hodgson May 10, 1921 1,511,842 Schmidt Oct. 16, 1924 1,667,231 Wood Apr. 24, 1928 1,864,584 Cowdery June 28, 1932 1,968,550 Barnes July 31, 1934 1,974,365 Oliver Sept. 18, 1934 2,115,908 Fox May 3, 1938 2,318,837 Connor May 11, 1943 2,356,272 Reynolds Aug. 22, 1944 2,373,459 Colwell Apr. 10, 1945 2,425,543 Landgraf Aug. 12, 1947 FOREIGN PATENTS Number Country Date 110,869 Great Britain Nov. 8, 1917