US2073893A - Apparatus for stamping and punching sheet metal and the like - Google Patents

Description

March 16, 1937. A L, A, wlLKfE 2,073,893

APPARATUS FOR STAMPING AND PUNCHING SHEET METAL AND THE LIKE Filed Sept. 26, 1932 y Patented Mar. 16, 1937 UNITEDl STATES APPARATUS FOR STAMPING ANDPUNCHING i SHEET METAL AND THE LIKE Leighton A. Wilkie, Minneapolis, Minn.

Application September 26, 1932, Serial No. 634,885

2 Claims.

This invention relates to the apparatus for stamping and punching sheet metal and the like.

One of the objects of the invention is the provision of a new and improved device :for making 5 metal stampings that may be employed in connection with the conventional punch press.

A further obj ect of the invention is the provision of a new and improved punch press mechanism having novel means for maintaining the punch element in contact with' the metal during the stamping operation.

Another object of the invention is the provision of a new and improved punch mechanism employing comparatively light inexpensive plates and a cooperating punch for piercing and stamping sheet metal articles of various shapes and deeration and that is not likely to become broken or get out of order.

Other and further objects and advantages of the invention will appear from the following description taken in connection with the accompaying drawing, in which- .Figl 1 is a plan view of ythe device;

Fig. 2 is a section on the line 2-2 of Fig. 1; and

Fig. 3 is a section on the line 3-3 of Fig. 1 showing the parts separated.

It is common practice in the manufacture of punching and stamping presses of the reciprocating type to 'prepare at considerable expense die and punch blocks for making stampings of sheet metal and the like.

In this form of construction, the punch element is rigidly mounted on the punch block and considerable time, labor and expense are required to align the punch with the die opening in the die block and to provide proper guides for accurately guiding the punch block in its reciprocating movements whereby stampings of the desired form may be made from suitable stock fed to the machine.

In the manufacture of stamped articles, it isnot uncommon that only a-limited number are desired and where the conventional press is employed, the cost of the dies is a material. consideration, and, in many cases, not only the principal factor in calculating the cost of the manufacture of the article, but is relatively so' high as to pro- 55 hibit the manufacture of the stamping.

The present invention seeks to eliminate these difliculties by the provision of what, for convenience of description, will be termed a punching or `stamping unit. This unit is made from comparatively thin plates, the die plates usually being not over M1 to l/q" in thickness, while the guide, or stripper, plate is usually much less in thickness. The punch element is carried by and constitutes a part of this unit assembly. The unit is inexpensive to produce and may be operated with the conventional punch press mechanism.

Referring now to the drawing in which is shown one embodiment of the invention, the blanking unit comprises a lower or bed plate 44, a die plate 45 and punch element guiding plate 46. The plates 45 and 46 are rigidly connected together and are spaced apart by spacer members 41 and 48 which are separated a sufficient distance toreceve the stock material I8. The plates 45 and 46 are rigidly connected together as by means of rivets or the like and the plate 45 is positioned on the plate 44 by any suitable means, such` as the dowel pins 4.9 which are adapted to engage corresponding openings in the plate 45.

A suitable punch element is provided for stamping out the blanks. In the form of construction shown, a hollow punch element 5| is employed which is adapted to cooperate with die plate 45 and a die member 52. The die member is adapted to fit in the opening 53 of the hollow punch element 5I. In order to properly position the die element 52 on the bed plate 44, the die member 52 and the plate 44 are provided with positioning means, such as projection 56, on said member which is adapted to engage the corresponding opening 51 in said plate.

The plate 46 is provided with a guide opening 54 for receiving the punch element 5I and the plate 45 is provided with a corresponding opening 55 for forming the marginal edge of the blank. The die member 52 is adapted to cooperate with the punch element 5I to punch outa portion of the blank that is being formed'. When the parts are assembled, the stock material I 8 is placed in position and the upper, or cutting, edge of the member 52 will be in contact with the lower surface of said material, and the lower, or cutting, edges. of theelement 5I will be in contact with the upper surface of said material.

In the operation of the device, the unit is placed between the blocks of a punch press with the element 23 contiguous to or in contact with the stock I8, and upon lowering the movable block of the press the punch element 5I will stamp out the blank from the material I8. This blank may be in the form of an annulus as shown, or other form, depending on the constructions of the com'- pound die and die plates.

The operator will then move the unit from the press punch and on separating the bed plate 44 from the die plate 45, the stamped article, or blank, and the punch element are removed, after which the parts are reassembled, the stock material advancing to the proper position for the next operation, the punch element placed in position within the opening 54 and the unit placed between the blocks of the punch press in position for the next operation.

It will be noted that in the form of construction disclosed, an inexpensive unit for operating on the metal is provided which is adapted to be operated by the mechanism of a conventional punch press.

The making of one of these units is a simple matter. For instance, a plate of cold rolled steel, say 1A thick, wide enough for the required blank, is cut off to the desired length. Another plate of the same width and length, but thinner, say 1/8" thick, is cut off from like material, and the two riveted together in vertical alignment by a rivet adjacent each corner. The proposed blank is then laid out on the outer surface of the thinner plate, using blue vitrol or similar composition as is usual in the die-making art.

The hole for the blank is drilled through both plates and filed out in the conventional manner, after which the rivets are removed and the plates hardened. This hardening process is important, but a simple one. The die is immersed in a cyanide bath at almost 1400 F. from 45 minutes to 11/2 hours, depending upon the thickness of the stock. The following composition has been found to give satisfactory results:

Formula for cyanide bath,

Per cent by volume (approx.)

Sodium cyanide 75 Carbonate of magnesia 5 Sodium carbonate Common salt 10 If the die and punch are to blank stock thicker than .095 andthe die plate is over thick, the die after being heat treated may be quenched in water, but if less than that it may be quenched in oil.

For light gauge metal blanking, quenching in oil gives excellent results.

The punch is made and hardened in like manner.

The two plates are then assembled with the spacers between the same and the whole riveted together by rivets tted in the corner holes. The stock to be blanked is inserted in the unit and the punch inserted in the guide opening in the upper or guide plate, and the unit is then ready to be placed between the blocks of the punch or stamp Dress.

If a very large number of stampings are to be made, the punch and die plates may be made, if desired, from tool steel, but ordinarily the units outlined above will produce from 2,000 to 10,000 stampings. Since this system is designed primarily to meet the requirements of the manufacturer desiring stampings in limited numbers, as on experimental jobs in large manufacturing plants and the like where it is desired to limit the costs, dies and punches from cold rolled steel, heat treated, as above, may be employed for making stampings in larger numbers.

Stampings that would ordinarily require dies, the material of which alone would cost from $15.00 to $20.00 and require 60 to 65 hours of time to make, can be made by the present system from dies, the material of which would not cost over 40 to 45e and require only 7 or 8 hours to complete. l

While only one embodiment of my invention is disclosed, it is understood that the idea of separate and independent units assembled as disclosed above and capable of being used with punch and like press operating mechanisms may be employed in like manner for perforating compound punching operations to produce blanksI of various types and designs.

What I claim, therefore, is:

1. A portable die block adapted to be operated by a conventional power press without attaching the same to said press, comprising a die plate having a die opening therethrough, a guide plate having a guide opening therethrough, said guide plate having an unobstructed plain outer face, and the intermediate portions of the adjacent faces of said plates being spaced apart a sufiicient distance to form a guideway for a metal blank while being operated upon by said unit, a supporting plate beneath said die plate and in contact therewith, said supporting plate having an unobstructed plain lower surface and provided with an opening therethrough of less diameter than said rst-named openings and in axial alinement therewith, a die element having a holding shank engaging in the opening in said supporting plate for positioning said element, said element being of materially less diameter than the opening through said die plate and having its upper surface in the horizontal plane of the upper surface of said die plate, and an annular punch element of a height less than the distance between the upper face of said guide plate and the lower face of said die plate, whereby articles may be stamped from stock material and openings stamped therein simultaneously by said unit in one operation.

2. A stamping unit adapted for compound blanking, comprising a bed plate, a die element supported thereon, a die plate having a die opening therethrough, a punch element positioning plate, spacer elements between said die plate and positioning plate and spaced apart for forming a slot for receiving stock material to be operated upon, means for rigidly securing said die plate, spacer elements and positioning plate together, means for removably positioning said die plate and die element in the same plane on said bed plate with said die element within said die opening, and a hollow punch element engaging an opening in said positioning plate for positioning said punch element relatively to said die plate and die element whereby when said punch element is forced downward, a blank will be simultaneously stamped from said stock material.

LEIGHTON A. WILKIE.

CERTIFICAT-E oF fcoRREcTioN.

Patent No. 2,073,893. 1 March 16, 1957.

LEIGHTON A. WILKIE.

v It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second oo1`umn, line 19, for4 the word "perfor-ating" read performing; and that the said Letters Patent should be read with this correction therein thatv the I1s-ame may conform to the record of the case in the Patent Office.

Signed and sealed this 27th day of April, A. D. 1937.

Lesli'e Frazer n (Seal) Acting Commissioner of Patents.

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