US 3320843 A
Description (OCR text may contain errors)
May 23, 1967 c. M. scHo'r'r, JR
PUNCHING DEVICE Filed Feb. 19, 1965 United States l atent C l 3320,8415 PUNCHHNG DEVllCl-E Charles M. Schott, .lr., Gioucester, Mass, assignor to Gioucester Engineering (30., Inc., Gloucester, Mass, a corporation of Massachusetts Filed Feb. 15%, 1965, Ser. No. 433,964 12 Claims. (Cl. 83-620) ABSTRAiIT F THE DISCLQSURE This invention relates to hole punching devices for use with web materials.
One object of the present invention is to provide a very simple, inexpensive hole punching device. Another object of the invention is to provide a punching device for which the alignment of the punch and die parts of the device, supported on opposite sides of the web, is not critical. Another object of the invention is to provide a means for inexpensively forming multiple holes in web materials such as plastic film.
Other objects are to provide perforators for plastic film, e.g. for ventilation purposes, that have long life, are quiet in operation, involve low speeds and forces, low power consumption, and are inexpensive to produce.
These and other objects of the invention will be revealed in connection with the drawings wherein FIG. 1 is a side view, partially in cross-section, of a preferred embodiment of the punching device of the present invention; FIGS. 2 and 3 are horizontal cross-sectional views taken on lines 2-2 and 3-4: respectively of FIG. 1; FIG. 4 is a perspective View of the punching device acting upon a web; FIG. 4a is a side view of the punch of FIG. 4 taken on a magnified scale; FIG. 4b is a view similar to FIG. 4a of the punch turned 90"; FIG. 40 is a development, upon a horizontal plane, of a cutting edge of the punch; FIG. 5 is a side view of a multiple hole punching machine; and FIG. 6 is a plan view of the machine of FIG. 5.
Referring to FIGS. 1-4c, a preferred embodiment of the invention comprises an elongated tubular punch member Ill and a die member 12. The die member has an outer annular Wall 13 and a pin member is inside thereof, the two defining an elongated annular cylindrical slot 14.
The punch member It) has its outer diameter d, smaller than the inner diameter d of annular wall 13 and has its inner diameter d larger than the outer diameter d of pin member 15, the respective diameters sized to permit a substantial latitude of misalignment without interferonce, while still the pin member 15 sized to offer a substantial web-supporting top surface 15''; for instance the members are sized with d=.275"; d =.250"; d =.225; and d =.200".
Advantageous-ly, as shown, both the top surface 15 of the pin 15 and top surface 13' of annular wall l3 are flat and aligned substantially in a single plane, for engaging and supporting the web face-wise without distorting it.
3,32%,343 Patented May 23, 1967 ice Advantageously, for rest-raining the web from entering the relatively large slot, the annular web-engaging surface 13' is of a substantial radial extent, preferably at least equal to a major fraction of the outer diameter of the punch member, exposed to frictionally engage and restrain said web.
The cutting end of the punch member if is specially shaped. Referring to FIGS. 4 to 40, the punch member 10 has at least one, and preferably a number of points 16- formed by the wall of the tubular member, and the tubular member is cut away so that the portion 18 of the edge in the vicinity of point 16 lies at a highly acute angle A to the axis X of the punch, e.g. an angle of 20. The edge proceeds at an acute angle though, preferably, of slightly increasing value. Preferably there is a transition region where a portion 20 of the edge joins the two edge portions 18 coming from opposite directions. In the transition region the portion 24) of the edge is preferably generally arcuate of relatively small radius r, and, in development, crosses the axis X, see FIG. 40.
The entire edge is preferably in the general form of a half ellipse when developed on a horizontal plane.
Preferably, as shown, the cutting edge is provided at the inner surface of the punch, in the region of greatest tension, with outer portions of the tubular wall cut back at an angle, as perhaps may best be seen in FIG. 4, and preferably the points in are equally spaced about the periphery of the punch member, to equalize tension.
Advantageously, especially from the point of view of simplicity of manufacture, the edge and cut-back portions are formed as a series of areas ground upon the end portion of the tubular member 10, and extending at acute angles to the axis of the tubular member. In the preferred embodiment employing a pair of diametrically opposed points 16, each section of edge lying between the two points is formed by a flat 20a including the transition portion 20 of the edge, and two curved ground areas 18a adjacent the points 16, each including a respective portion 18 of the edge that lies at a highly acute angle A to the axis X.
Referring to FIGS. 1-4c the punch point 16 is located to lead into the relatively large annular slot 14, though permissibly axially misaligned. As the point 16 engages the web, the web is pressed against the support surfaces 13, 15'. Preferably, as in the case of a pair of diametrically arranged points, the web, in addition, is tensioned, and pulled tautly about the top surface 15 of pin 15.
As movement of punch it towards die 12 occurs, the web is punctured and cutting then commences, first in the immediate vicinity of the point 16 and at a slow rate, due to the acuteness of angle A. After the initial puncture, which offers greatest resistance, tension is still preferably applied to the web by at least two points. The cutting proceeds along the cutting edge, .and with the preferred edge form as shown, the cutting rate increases, taking advantage of the web tension, enabling the stroke length to be reduced.
Accordingly, by virtue of the support surfaces and the acute angled relation of the leading cutting edges, the hole is punched by a slicing action that does not depend upon accurate alignment of the punch member in with the die member 12. This is of great advantage, especially in wide machines where the supporting bar for the punch members is only remotely connected to the supports for the corresponding die members, and therefore diflicult to align.
Referring to FIGS. 5 and 6, a multiplicity of the punch members 10 are mounted on a supporting bar 21 that extends across the width of web 22 to be punched. Each punch includes a stationary guide and stripper cylinder 24, and a return spring 26 located between cylinder 24 and bar 20. Reciprocating means 30 are arranged to cause downward movement of bar 20 whenever the web 22 is stopped; in the embodiment shown, stopping of the film is achieved by moving shuttle 32 to the right at /2 web speed, and synchronizing reciprocation of punch 16 and shuttle 32 by means of a cam shaft 34.
The die members 12 for the various devices are located on stationary supports relative to the machine, beneath the web path and arranged to receive the axially misaligned punch members 10 when they move downward with bar 21. It will be appreciated that, due to the ability of the punch devices to tolerate misalignment, the die supports and related equipment, hence the entire machine, is less expensive to manufacture and maintain.
Referring to FIGS. 4a and b again, the special formation of the punch member is easily achieved by means of grinding a tubular member. The grinding operation that forms circular edge 20 and fiat 20a is preferably first achieved by a fiat grinding surface that is brought against the end of the tube at an angle to the axis of the tube, and generally aligned with what will be the pair of points 16. The edges 18 and surfaces 18a are then formed by grinding surfaces which also form an angle relative to the axis of the punch member, but are progressively curved, for instance by a hand grinding operation, one to one side and the other to the other side of the plane of the first grinding surface so as to form curved surfaces 18a as shown in FIG. 4b which lie at opposite Sides to the central fiat 20a, the three ground surfaces providing a sharpened blade edge throughout the half ellipse, and sharpened points at ends 16.
Preferably a through hole 40 is provided through the punch 10, enabling removal of waste.
Various modifications of the specific details will occur to those skilled in the art.
What is claimed is:
1. A hole punching device for use with web materials comprising a punch member and a die member, said punch member comprising, at its cutting end, a hollow tubular member having at least one web-piercing point and a blade edge extending substantially throughout the remainder of the periphery of the tubular member, the blade edge, at least in the region of said point, on both sides thereof, extending, as developed, at a substantially acute angle, relative to the axis of said tubular member away from said point, said die member defining an annular wall and a pin member located therewithin, said pin member and said wall defining an annular passage having a substantially larger radial dimension than the Wall thickness of said tubular punch, adapted to permit axial misalignment between said punch member and said die member, the outer surfaces of said wall and said pin providing web-engaging surfaces.
2. The hole punching device of claim 1 in combination with a multiplicity of said devices, the punch members located on one side and the die members located on the other side of said web, the punch members of said devices mounted on a support adapted to reciprocate relative to said die members, said support being an elongated member arranged to extend across a substantial part of the width of said web.
3. The hole punching device of claim 1 wherein a cutting edge portion remote from said point extends at a substantially greater angle to said axis than the cutting edge portions adjacent said point, whereby the cutting rate, relative to punch travel, is increased after the leading part of said punch member enters said die.
4. The hole punching device of claim 1 wherein said outer surfaces of said pin and said annular wall are fiat and aligned on the same plane.
5. The hole punching device of claim 1 wherein there are at least two punch points, the central part of the cutting edge line between adjacent points is defined by a central ground flat aligned with said adjacent punch points.
6. The hole punching device of claim 1 wherein said outer surface of said annular Wall provides a substantial area for face-to-face contact with said web, the radial dimension of said surface being at least equal to a major fraction of the outer diameter of said punch member.
"7. A hole punching device for use with web materials comprising a punch member and a die member, said punch member comprising, at its cutting end, a hollow tubular member having at least one web-piercing point and a blade edge extending substantially throughout the remainder of the periphery of the tubular member, the; blade edge, at least in the region of said point, on both sides thereof, extending, as developed, at a substantially acute angle, relative to the axis of said tubular member away from said point, said die member defining an annular wall and a pin member located therewithin, said pin member and said wall defining an annular passage having a substantially larger radial dimension than the wall thickness of said tubular punch, adapted to permit meial misalignment between said punch member and said die member, the outer surfaces of said wall and said pin providing web-engaging surfaces, there being at least two points spaced about the cutting periphery, said points arranged to draw said web taughtly about the outer surface of said pin to enhance the cutting action.
8. The hole punching device of claim 7 wherein said cutting edges are curved from point to point, in the general form of half-ellipses, with the smallest radius of said curved edges substantially spaced apart from said points.
9. The hole punching device of claim 7 wherein said outer surface of said annular wall provides a substantial area for face-to-face contact with said web, the radial dimension of said surface being at least equal to a major fraction of the outer diameter of said punch member, said cutting edge being located at the inner surface of said tubular member, arranged to shear said web near said pin member about which said Web is taughtly drawn.
10. The hole punching device of claim 9 wherein said points are spaced substantially equally about the periphery of said tubular member, arranged to uniformly tension said web about said pin.
11. The hole punching device of claim 10 wherein there is a pair of diametrically arranged points, each edge lying between said two points.
12. The hole punching device of claim 11 wherein each edge is formed in part by a central fiat extending i a plane generally aligned with said pair of points.
References Cited by the Examiner UNITED STATES PATENTS 247,645 9/1881 Long 83l26 X 2,093,202 9/1937 Maynes 83689 X 2,475,807 7/1949 Smith 83145 3,045,518 7/1962 Kjelgaard 83588 X WILLIAM W. DYER, JR., Primary Examiner.
JAMES M. MEISTER, Examiner.