US3446105A

US3446105A - Notching unit

Info

Publication number: US3446105A
Application number: US611425A
Authority: US
Inventors: John H Herzog
Original assignee: Houdaille Industries Inc
Current assignee: Strippit Di Acro Houdaille Inc
Priority date: 1967-01-24
Filing date: 1967-01-24
Publication date: 1969-05-27
Anticipated expiration: 1986-05-27

Description

May 7, 1969 J. H. HERZOG 3,446,105

NOTCHING UNIT File d Jan. 24, 1967 INVENTOR. JOA/A/ 1452206 m gm d, 4 ATTORNEYS United States Patent 3,446,105 NOTCHING UNIT John H. Herzog, Clarence, N.Y., assignor to Houdaille Industries, Inc., Bulfalo, N.Y., a corporation of Michigan Filed Jan. 24, 1967, Ser. No. 611,425 Int. Cl. B26d 7/06, /08, 1/12 US. Cl. 83-146 14 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Field of the invention This invention deals with a cutting or notching device which includes means to drive or to guide the reciprocable tool or punch which is constantly urged by spring means in one direction during both the cutting and the non-cutting strokes.

Prior art The prior art device with which I am most familiar is that shown in US. Patent No. 3,213,741, owned by the assignee of the present invention. That device constituted an advance over the then-known art, but commercial experience with it has demonstrated certain limitations. It was conceived as an edge-notching unit primarily, but when users inserted workpieces of steel of substantial thickness utilizing only two adjacent cutting edges, the unbalanced forces thus produced tended to cause the cheek plates thereof to spread, thereby permitting or causing damage to the punch and die. Also, when particularly heavy-duty notching is performed using three cutting edges, on occasion the strength of the springs was inadequate. Further, with this construction, for various thicknesses of material, various punch and die clearances had to be employed, thus necessitating substitution of either the punch or the die. Further, lubrication difiiculties were encountered, particularly on the lateral sides of the punch holder. Further, the structure shown in Patent No. 3,213,741 in certain instances tended to deform the finished blank, thereby requiring added corrective action.

SUMMARY In accordance with the present invention, I have provided a structure which overcomes all of the problems described above. Life tests conducted to date show that the structure of this invention is particularly reliable and enduring, that greatly unbalanced reactive forces have no adverse effect on the device, that stripping forces are always adequate, that a single die clearance may he employed for a wide range of materials, that lubrication is easily accomplished, and that feeding of the workpiece may be either through the device in the conventional lateral manner, or at will at right angles thereto.

A punching or notching unit according to the present invention includes a C-shaped base which is a single element including an upper arm and a lower arm between which there is a throat for passage of the workpiece. A punch holder is provided with a cylindrical body that is 3,446,105 Patented May 27, 1969 slidably guided in a bore in the upper arm, the body diameter being greater than the guided length thereof. A particularly advantageous arrangement of dished circular washer springs is provided which has economic advantages and functional advantages which not only perform as expected but which prevent cocking of the holder body described. A removable snap-on stripper plate is secured to the underside of the upper arm, and the base has a passage at the rear of the throat permitting front-to-read feeding as well as lateral feeding of the workpiece.

Accordingly, it is an object of the present invention to provide a notching unit which may be employed for edge notching, corner notching, and for other punching.

A further object of the present invention is to provide a cutting unit of the type described wherein the workpiece may be fed through the device either laterally or in a front-to-rear manner.

A further object of the present invention is to provide a punching or notching unit wherein the space occupied by the unit above the workpiece has a relatively low vertical extent in relation to that normally necessary for a particular punching area.

A still further object of the present invention is to provide a punching unit which eliminates all of the problems enumerated in the discussion of prior art above.

Many other advantages, features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheet of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.

On the drawings:

FIG. 1 is a side view, drawn in vertical cross section, of a notching unit provided in accordance with the principles of the present invention;

FIG. 2 is a top view thereof in reduced scale; and

FIG. 3 is a view corresponding to FIG. 1 of a somewhat larger embodiment of this invention, drawn in reduced scale.

As shown on the drawings:

The principles of this invention are particularly useful when embodied in a punching unit of the notching type, such as is illustrated in FIG. 1, generally indicated by the numeral 10. The device 10 includes a C-shaped base 11 which is a one-piece member including an upper arm 12, a lower arm 13, and a portion 14 which integrally joins the

arms

12, 13 together, thereby defining a throat 15 which is receptive of a workpiece (not shown).

The lower arm 13 has a lower surface which is adapted to be secured directly or indirectly to the bed of a press, and to that end, the lower arm 13 includes conventional fastening and guidance means, as shown. The lower arm 13 detachably supports a notching die 16 which in this embodiment has a U-shaped cutting edge 17 which extends for part of the lateral width of the base 11, and rearwardly to the rear end of the throat 15.

The upper arm 12 has a cylindrical bore 18 extending therethrough, and within this bore there is slidably guided a punch holder or punch holder assembly 19. The punch holder 19 includes a cylindrical body 20' which has a diameter that is slidably guided by the bore 18. The cylindrical body 20 has a guided length which is shorter than its diameter, and in accordance with the present invention, the diameter of the cylindrical body 20 may not only be greater than such guided length, but may be several times greater, as illustrated below in FIG. 3. The punch holder 19 includes a punch tip 21 which may be integral with the body 20 or which may be removably secured thereto as shown in FIG. 3. The punch tip 21 in this disclosure is a notching punch tip having a U-shaped cutting edge corresponding to the die cutting edge 17 for cooperation therewith. The punch holder 19 has a coaxial stem 22 either integral therewith as shown in FIG. 1 or secured thereto as shown in FIG. 3, the stem 22 having a diameter less than that of the body 20. The punch holder assembly 19 further includes a ram plate 23 having an upper surface 24 for being engaged by the ram of the press. The ram plate 23 is secured as by a number of screws 25 to the punch holder body 20. The ram plate 23 has a size in a direction parallel to the diameter of the cylindrical body 20 and parallel to the diameter of the stem 22 which is of greater extent so that the ram plate projects therebeyond to engage the central portion of the uppermost one of a number of dished circular washer springs 26-28. It is desirable that the ram plate 23 have a dimension such as a diameter which is larger than the bore 18 to enable its lower side near the outer periphery to engage the outer periphery of one of the springs 26-28 if they were arranged differently.

The spring means 26-28 act as a single spring between the upper arm 12 and the punch holder 19, and in this instance against the ram plate 23.

The upper arm carries a key 29 which is secured to the upper arm in a slot 30 and which projects into the bore 18 and is received within a vertical groove 31 extending through the guided length of the body 20. A retainer screw 32 shown in FIG. 2 extends into a further slot or groove 33 in the body 20 and is engageable by an upwardly directed shoulder 34 to retain the punch holder assembly 19 within the base 11.

The upper arm 12 includes a lubrication passage 35 which is accessible externally through a grease fitting 36 and which communicates at its inner end with a groove 37 in the cylindrical bore 18, the groove 37 being circular and opening toward the body 20 and encircling it for conducting lubricant to it.

The rear end of the bore 18, indicated by the numeral 38, extends to the rear of the inner end of the throat 15, indicated by the numeral 39, whereby the rear 39 of the throat 15 is closer to the front of the device than is the rear 38 of the bore 18. Thus the guide surface of the cylindrical body 20 extends beyond various cutting edges of the notching die 21.

The lower arm 13 of the base 11 is provided with a chute 40 through which slugs formed by the punch 21 and die 16 may pass. Also, the portion 14 of the base 11 which joins together the upper and

lower arms

12, 13 is provided with a passage in a front-to-rear direction, such passage being indicated by the numeral 41 and extending upwardly to substantially the top of the gap 15. The passage 41 has a" width which is substantial, thereby enabling a workpiece to be fed to or from the front of the device 10, beneath the punch and die, and through the passage portion 41 and to or from the rear side. In the present embodiment, for convenience, the slug chute 40 has been combined with the workpiece passage 41 into a single passage in which both the workpiece and the slugs may simultaneously pass. This arrangement is particularly advantageous in that the device may be used as a cut-01f tool without wasting workpiece material.

The dished circular washer springs 26-28 are heavy duty springs, and depending on their size, have a typical relatively high cost. It is therefore highly advantageous to use a minimum number of such springs. The more springs that are used, the less the stripping force will be. The more springs that are used, the greater the punch travel will be. Therefore, the ideal combination can be brought about using a minimum number of springs as described provided that the stem 22 is of reduced diameter so that the hole in the springs 26-28 may be of a minimum size. In the embodiment shown in FIG. 1 using springs that are about 2% inches in diameter, it would take about 1,000 pounds of force to close the notching unit to its shut height. In the embodiment of FIG. 3, it would take about 6,000 pounds of force to close it to shut height, using a travel of about /2 inch. These values are representative of the term heavy duty as used herein, and they are also so great that there is a correspondingly high force between the ram plate 23 and the ram of the punch press (not shown) so that even if an unbalanced force were applied to the punch tip due to corner notching, such spring force would hold the ram plate 23 squarely against the ram, thereby enabling the cylindrical body 20 to move verically without any appreciable tendency to cock or bin The device 10 includes a stripper plate 42 of U-shaped configuration which extends from the rear 39 of the throat 15, in a manner that encircles three sides of the punch tip 21, the inner periphery of the stripper plate 42 having a profile corresponding to the punch tip 21. The stripper plate 42 is readily removable to provide its being replaced by one having a desired clearance, or to provide for its being replaced by one having a configuration to match a different punch tip 21. To this end, a number of spring fingers 43 are carried by the upper arm, one being shown at the front, and there being two others at the sides in an identical manner. The stripper plate 42 underlies and is thus disposed against the lower surface of the upper arm 12, and has a beveled edge against which the spring fingers 43 act to so urge and hold it. The spring fingers 43 are also referred to herein as snap-on retainer means which have a snap fit with the stripper plate 42.

To use the notching unit, it is mounted on the bed of a press beneath the ram and a workpiece is fed through from side to side or from front to rear, and may pass through the base 11 rearwardly if it is in the nature of an elongated strip. The punch tip in FIG. 1 has a dimension of 1 /2 x 1 inch, and a punch holder can be provided which has any punching configuration falling within that area, and with which a corresponding die is utilized. The punching pattern thus may comprise edge-notching, corner-notching, hole punching, cut-off, or the like. The key 29 aligns the punch 21 with the die 16 and also precludes rotation thereof during cut-oil use or during corner notching at one side of center. The structure of FIG. 1 can be provided with .002 die clearance to enable it to handle workpieces as thin as shim stock and as thick as .134 inch. The structure is particularly advantageous in that any set taken by one of the

springs

26, 28 does not disturb alignment, and the Belleville springs are further advantageous in that they provide inherently absolutely uniform reaction to downwardly guided movement before the workpiece is engaged.

According to what one might expect who is not familiar with my teaching, one might believe that the use of a punch holder body diameter which is greater than its guided length is either impossible, impractical or a poor feature. However, my experimentation has shown that the device of this invention operates properly on much less and on much more than the theoretically necessary stripping force, thereby demonstrating an unobvious advantage.

The device of FIG. 3 corresponds in all important aspects to the device of FIG. 1 except that it is larger. It is thus economically advantageous to use only two Belleville springs, to use several screws, and to use a separate stem and punch tip, all as described above. For this reason, similar numerals have been atfixed to the elements of FIG. 3 accompanied by the suflix letter a. The space underlying the punch tip 21a is three inches wide and five inches long.

Although various minor modifications might be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent warranted hereon, all such embodiments as reasonably and properly come within the scope of my contribution to the art.

I claim as my invention:

1. A device for use between the bed and ram of a press, comprising in combination:

(a) a C-shaped base having an upper arm and a lower arm, said lower arm being adapted to be secured to the press bed and adapted to detachably support a die;

(b) a punch holder slidably disposed in a bore in said upper arm, and adapted at one end to support a punch tip and to guide it in registration with the die, and to be engaged by the press ram at the other end; and

(c) spring means acting between said upper arm and said punch holder for biasing said punch holder away from the die;

(d) said arms being spaced to define a throat which permits a workpiece to pass through said base between the punch and die from one lateral side through the other, and said base having a passage through the portion thereof which joins said arms, said passage extending to the height of said throat to permit a workpiece to pass through said base from the front side through the rear side.

2. A device according to claim 1, in which said base has a slug chute through the lower portion of which slugs can pass, and the upper portion of which is said passage through which the workpiece can simultaneously pass.

3. A device according to claim 1, in which said base including both of said arms comprises a one-piece memher.

4. A device for use between the bed and ram of a press, comprising in combination:

(a) a C-shaped base having an upper arm and a lower arm, said lower arm being adapted to be secured to the press bed and adapted to detachably support a notching die;

(b) a punch holder slidably disposed in a bore in said upper arm, and adapted at one end to support a notching punch tip and to guide it in registration with the die, and to be engaged by the press ram at the other end;

(c) spring means acting between said upper arm and said punch holder for biasing said punch holder away from the die; and

(d) a generally U-shaped stripper plate underlying and supported against the lower surface of said upper arm and having an inner edge corresponding to the cutting edges of the punch tip for being spaced slightly therefrom.

5. A device according to claim 4, in which means are carried by the front and lateral sides of said upper arm for removably supporting said stripper plate thereon with a snap fit.

6. A device according to claim 1, in which there is a generally U-shaped stripper plate underlying and supported against the lower surface of said upper arm, which plate has an inner edge corresponding to the cutting edges of a punch tip for being spaced slightly therefrom.

7. A device for use between the bed and ram of a press, comprising in combination:

(b) a punch holder having a cylindrical body slidably disposed in and directly guided by a cylindrical bore in said upper arm, and adapted at its lower end to support a punch tip and to guide it in registration with the die, said cylindrical body having a diameter greater than its guided length;

() a stem rigidly secured to the upper end of said punch holder and disposed coaxially therewith, said stem having a dimension parallel to and somewhat smaller than said body diameter;

(d) a ram plate, having a dimension parallel to and somewhat greater than said dimension of said stem, for being engaged by the press ram, and being rigidly secured to said stem; and

(e) a plurality of dished circular washer springs with a hole diameter smaller than said body diameter and encircling said stem and acting between said upper arm and said ram plate, and biasing said ram plate against the ram during punching with such biasing force as to hold the upper surface of said ram plate flatly against the ram, thereby to preclude any cocking of said punch holder body in said bore when an unbalanced reactive force is applied to the punch tip by the workpiece.

8. A device according to claim 7, in which said arms are spaced to define a throat through which a workpiece can pass between the punch and die from one lateral side of said base through the other, said base having a passage through the portion which joins said arms communicating with said throat and enabling a workpiece to pass from the front side through the rear side of said base.

9. A device according to claim 7, in which there is a generally U-shaped stripper plate underlying and supported against the lower surface of said upper arm, which plate has an inner edge corresponding to the cutting edges of a punch tip for being spaced slightly therefrom.

10. A device for use between the bed and ram of a press comprising in combination:

(b) a punch holder having a cylindrical body slidably disposed in and directly guided by a cylindrical bore in said upper arm, and adapted at its lower end to support a punch tip and to guide it in registration with the die, said cylindrical body having a diameter greater than its guided length, the rear surface of said cylindrical body and said cylindrical bore being farther from the front of said base than is the rear end of the throat between said arms, the upper end of said punch holder being disposed to be engaged by the press ram; and

(c) heavy duty spring means acting between said upper arm and said punch holder, and biasing said holder against the ram during punching with such biasing force as to hold the upper surface of said punch holder flatly against the ram, thereby to preclude any cocking of said punch holder body in said bore when an unbalanced reactive force is applied to the punch tip by the workpiece.

11. A device according to claim 7,

(a) said base, including both of said arms, being a onepiece member, said arms being spaced to define a throat through which -a workpiece can pass between the punch and die from one lateral side of said base through the other, said base having a chute in said lower arm and extending through the portion which joins said arms and extending upwardly to the top of said throat, whereby slugs can pass through the lower part of the chute and a workpiece can simultaneously pass through the base from the front side through the upper part of said chute and through the rear side;

(b) the rear end of said throat being closer to the front of said base than is the rear end of said cylindrical bore;

(c) there being a generally U-shaped stripper plate underlying and supported against the lower surface of said upper arm, which plate has an inner edge corresponding to the cutting edges of a notching punch tip for being spaced slightly therefrom; and

7 8 (d) there being means carried by the front and lateral References Cited sides of said upper arm for removably supporting said UNITED STATES PATENTS stripper plate thereon with a snap fit.

12. A device according to claim 7, said cylindrical body 2,338,093 1/1944 Caldwell 3085 X having a diameter more than twice as great a its guided 5 2,555,458 6/1951 Saxton 308 5 length and providing the sole sliding guidance for the 2,757,735 8/1956 Taylor 83 588 X punchtin 3,079,824 3/1963 Schott s3 5ss X 13. A device according to claim 9, in which means are 3,230,806 1/1966 Rovoldt 83 146 3,345,896 10/1967 Bennett 83-685 X carried by the front and lateral sides and said upper arm aosrngzmfptva 1y supportin said 5 Upper plate thereon W1 10 JAMES M. MEISTER Primary Examiner.

14. A device according to claim 7, in which the rear end US. Cl. X.R.

of the throat between said arms is closer to the front of said base than is the rear end of said cylindrical bore. 917