US2533528A - Process of making steel toe boxes - Google Patents

Description

Dec. 12, 1950 w. w. SOMERSALL 2,533,528

PROCESS OF MAKING STEEL TOE BOXES Filed A'oril 1, 1948 j'ezievzior M Patented Dec. 12, 1 950 PROCESS OF MAKING STEEL TOE BOXES William Warren Somersall, Natick, Mass., as-

signor to Beckwith Manufacturing Company, Dover, N. 111., a corporation of New Hampshire Application April 1, 1948, Serial No. 18,455

1 Claim. 1

The present invention consists in a new and improved process of making steel toe boxes by which the boxes may be produced in pairs as separate articles and with less waste of material than heretofore.

In manufacturing steel toe boxes by processes heretofore known, a single sheet steel blank has been die pressed into ellipsoidal form, then trimmed, and then separated into a pair of individual boxes. While this known process has been practised for many years, it has serious limitations and involves cost items that are obviated by the present invention; for example, if the ellipsoidal form is divided in a transverse line, the resulting boxes have straight transverse rear edges, whereas shoemaking requirements now demand steel boxes of wing tip shape or at least boxes in which the rear corners extend substantially behind or beyond the arched rear edge of the box in order to give it increased stability in the shoe and prevent the possibility of rocking under impact. An ellipsoidal blank can be separated to produce steel boxes of this kind only with considerable waste of material and requires a somewhat elaborate cutting operation to be carried out on each individual box.

The process of my invention is characterized by the employment of two separate flat blanks which may be located accurately and independently with respect to a single die cavity and from which two separate steel boxes are formed simultaneously by the operation of a single punch or male die as distinguished from the integral ellipsoidal form produced by the previously practised method.

Going more into detail, my improved process contemplates the employment of steel blanks which are roughly semi-circular or segmental in shape. These blanks are positioned above the opposite ends of a single die cavity with their transverse edges spaced in opposed relation and, if desired, these two transverse edges may be arranged in angular or convergent relation so that the resulting boxes are unsymmetrical and constitute rights and lefts. The process, therefore, has great flexibility and by simple angular adjustment of the two blanks, steel boxes of a wide range of diversity in shape may be produced. The necessity for a trimming operation on the transverse edge of the box is obviated and all waste of material is eliminated from the arched transverse edge portion of the boxes. If it is desired to produce steel boxes of wing tip contour, the transverse edge of the fiat blanks may be given a sinuous curvature and this curvature is brought through into the finished boxes without the necessity of any further trimming.

An important advantage of my novel process is that as the two blanks are forced into the die cavity and drawn, they act jointly to equalize and balance lateral pressure on the punch so that it operates without appreciable tendency to work toward one or other wall of the die. This not only improves the life of the die but contributes largely to uniformity of product.

As further and optional features, I contemplate the employment of a pressure pad to hold the fiat blanks individually and securely in position upon the die cavity preliminarily to the drawing operation on the blanks. Provision is also made for stamping the blanks to indicate size or style during the drawing operation. The latter steps are desirable but optional.

These and other features of the invention will be best understood and appreciated from the following description of one form of apparatus for carrying out the process, together with a detailed description of the preferred manner of practising the process. In the drawings:

Fig. l is a plan view of the female die showing a pair of blanks positioned thereon,

Fig. 2 is a corresponding view in longitudinal section showing the blanks in position in the die cavity after the forming step,

Fig. 3 is a plan view of a partially formed steel box as it appears after the drawing operation, and

Fig. 4 is a view in perspective of a pair of finished steel boxes.

The female die comprises a rectangular steel base I!) to which is secured a solid steel block ll having a single elliptical die cavity I2 formed therein. As will be apparent from Fig. 1, the cavity is not symmetrical but is substantially flatter on one side than on the other in order that the resulting boxes may be rights and lefts. Cooperating with the female die is a pressure pad I3 in the form of a frame having an annular wall 14 corresponding in shape to the die cavity l2. A punch [5 of the same contour works in the opening of the pressure pad. The punch is provided with a lower convex drawing surface. The pressure pad I3 is provided at each end with a hardened stud It held in place by a set screw I1 and projecting slightly below the lower surface of the pad. The projecting end of the stud is flattened to cooperate with a groove or recess N3 of similar shape formed in the upper surface of the female die H. The function of the stud I6 and recess I8 is to firmly engage the flat blanks and 3 hold them securely in position prior to and during the drawing operation.

In Fig. l I have shown a pairof flat segmental sheet steel blanks 2t and 25 lying flat upon the upper surface of the female die with their trans- Verse edges in opposed relation and spaced substantially from each other and from the center line of the die cavity; The dotted. line position indicates how the blanks may be swung to bring their transverse edges into converging relation when it is desired to approach a wing tipshape in the completed boxes The dashlines also indicate how blanks having sinuous transverse edges may be positionede After the blanks 28 and 211 have been properly positioned as in Fig. l, the pressure pad I3 is moved downwardly by power into the position shown in Fig. 2 in which it grips the outer curved margins of the two blanks against th v upper surface of the female die H at the same time pr jecting ends; of, thestuds force a portion of each: blank intothecorresponding groove [8; and. thus positively hold the marginof the bla-nk-against-being drawninwardly. The punch t5dis now moved. downwardly and: the two-blanks are drawn simultaneously; and; with equalized treatment into the shape indicated in Fig l and? Fig 4"; that: is to say, the dome-shaped; bodyof; cach box is formed: with its; archedrear edge 22, rearwardly; extending corner portions and a fiatmareinal flange 23,-.

In the; bottom of the diecavity is provided a pair of; stamping dies as each supported on a hard rubberiblocktland; located in position to: form; an impression-on the dome of; the molded tively: locked by the action of the studs [6-, thus insuring a predetermined; and: uniform; length of eaclr: box or; cap produced. It will be apparent that the size of; the resulting; box: may be con-- trolled. by; locating, the blanks. so as; to overlap more or less the area of the die cavity. For example, smaller boxes may be produced by increasing the spacing between the opposed edges of the blanks 2G and M as shown in Fig. 1.

The steel boxes partially formed as shown in Fig. 3 are now completed by the usual steps of trimming off the fiat marginal flange 23 and wiping in the marginal-amaterial' to; form". the intur-ne'd flange 2%, as shown in Fig. 4; At the conclusion of the forming operation, the domeshaped body of each blank is stamped with identifying. marks, such as RF-7 and L-7 as shown in Fig. 4', by the stamping die 39.

Having thus. disclosed my invention and described in detail an illustrative procedure for carrying it out, I claim as new and desire to secure by LetterstE'atent:

The process of making right and left steel toe boxes in pairs which includes the steps of locating a pair of segmental sheet steel blanks over ofpposit-elends: of a single elliptical die cavity'wi-th the inner; edges of. the: blanks. opposed in spaced relatio'nland disposed at a. predeterminedangle to'= each-1 otheiz g ripping. the outer curved margins: of both blanks, depressing both blanks-simultaneous- 1y into: opposite endsof the same die cavity thus drawing the steel; blanks. by equalized: pressure into rightand left: dome-shaped. bodies with out,- turnedflat; margins, trimming the flat margins;-

; andithenzmo lding the marginsito' provide inturned flanges.

W; \IVARR-ENC SQMERSAIiI-n REFERENGES" GI'TED Phefollowing references are of record in the file of this patent:

UNITED STATES PATENTS

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