US1025318A - Mandrel for sheet-metal working. - Google Patents

Description

L. O. SHARP.

MANDREL FOR SHEET METAL WORKING.

APPLICATION FILED MAR.8, 1907. RENEWED OUT. 2, 1911.

Patented May 7, 1912.

COLUMBIA PLANOGRAPM, uu., WASHINGTON, v4 :4

UNITED STATES PATENT OFFICE.

LEE 0. SHARP, OF PLATTSMOUTH, NEBRASKA, ASSIGNOR T0 FRANZ BRITCKMANN, JR., OF BRUNSWICK, GERMANY.

MAN'DREL FOR SHEET-METAL WORKING.

Specification of Letters Patent.

Patented May '7, 1912.

Application filed March 8, 1907, Serial No. 361,310. Renewed October 2, 1911. Serial No. 652,414.

To all whom it may concern:

Be it known that I, LEE C. SHARP, of the city of Plattsmouth, in the county of Cass and State of Nebraska, have invented certain new and useful Improvements in Mandrels for Sheet-Metal orking, of which the following is a full, clear, and exact specification, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates particularly to a mandrel for forming and holding can body blanks in position for seaming them.

It is especially adapted to the formation of lap seams, that is to say, in which one edge of the blank is lapped over the other to form the seam which is subsequently soldered to render it permanent. Heretofore devices of this sort have been composed of a horn or mandrel around which the blank tin is folded and held by wings or other devices engaging the tin.

The object of my invention is to dispense with these devices for engaging the tin to hold it on the horn.

A further object of my invention is to provide means for holding the lap parts of the body at the seam firmly together so that the engagement of the edges during the soldering operation will not depend upon the pressure of the soldering tool, thus enabling me to join together the two edges of the body blank and secure them by the fusing of the tin with which the metal plate is coated.

I attain these objects by magnetic action which may be through the mandrel itself, or a part in connection therewith. The magnet is preferably of the electromagnetic type, although my invention is not so limited.

My invention involves various other features of major or minor importance, and all will be fully set forth hereinafter and particularly described in the claims.

Reference is had to the accompanying drawings which illustrate, as examples various types of the invention, in which drawin s Tigure 1 is a sectional view of one form of the mandrel; Fig. 2 is a sectional view of a second form; and Fig. 3 is a sectional View of a third form.

In Fig. 1, the mandrel is composed of two approximately semi-cylindrical sections a which form the poles of the magnet and are joined by a magnet core 6 around whichthe winding 0 is placed. The can body blank indicated at (Z is folded either manually or by machinery over the mandrel or horn, and its edges lapped as indicated at d to form the lap seam. Upon energizing the coil 0 the blank will be attracted to the mandrel at the points indicated by the arrows in Fig. 1, and the magnetic force may be made sufliciently great to hold the sheet metal plate in position as firmly as will be desired under any condition. It will be observed that the force holding the blank is exerted from the interior of the mandrel as contradistinguished from the exterior thereof, thus leaving the outer side of the can body entirely free and unobstructed particularly at the seam, without, however, in any way affecting the force which may be exerted to hold the edges of the blank firmly lapped against each other. This allows the soldering operation to be carried on without restraint and when the can is to be removed from the mandrel the coil 0 may be deenergized and the can withdrawn easily. In sealing the seam by fusing the tin with which the metal plate is coated, my invention becomes peculiarly useful. It is a. fact that commercial tin plate composed of sheet steel coated with tin furnishes sufficient tin to solder the lap seam. However, it has been heretofore impossible to solder the scam in this manner owing to the fact that great pressure must be applied to the overlapped parts during the fusing operation, otherwise the parts will warp and the hermetic joint be prevented. By means of my magnetic mandrel, however, the lapped parts of the seam are held firmly against each other by pressure which may be as great as necessary and the heating operation necessary to fuse the tin and form the joint may be carried on unrestrained. The magnetic force may be continued on the seam until the tin cools 100 and sets, and the seam is then complete.

Fig. 2 shows a modification in which the mandrel is adapted to be provided with a number of longitudinally disposed windings of which one is indicated at c. windings are arranged in all of the cavities around the entire circumference of the mandrel with the result that upon energization of the windings the blank cl is held firmly at all points.

Similar Fig. 3 shows a form which is rectangular in cross section, adapted for the formation of square cans in which the parts a, Z), and 0 correspond to the parts a, b and c of Fig. 1, and perform precisely the same functions.

It is also pointed out in connection With this invention that the mandrel may be made of any length desired, thus enabling a can of any length to be constructed and indeed adapting the invention. to the formation of various other tubular sheet metal articles of indefinite length.

Having thus described the preferred embodiment of my invention, what I claim as new and desire to secure by Letters Patent of the United States is:-

1. A horn or mandrel adapted to support the blanks of sheet metal cans and having cross-sectional shape corresponding to that of the can, said horn or mandrel being provided with electromagnetic means acting upon the inner surface of the blank to hold the blank in position around the mandrel leaving the outer surface of the blank un obstructed.

2. A horn or mandrel adapted to have the blanks of sheet metal cans formed around it,

the horn or mandrel having a cross-sectional shape corresponding to that of the can and an electromagnetic means embodied within the horn or mandrel as a part thereof, whereby said blank may be held around the mandrel in position for soldering, leaving the outer part of the blank unobstructed during the soldering operation.

3. A horn o mandrel for forming the sheet metal cans comprising two sections forming the poles of a magnet and spaced from each other, said sections forming to the cross-sectional shape of the can, a mag net core joining the said sections together and an electric magnet Winding around the core, whereby the blank of the sheet metal can is held around the mandrel by electromagnetic force exerted from the interior thereof and the outer portion of the blank is left unobstructed during the soldering operation.

In testimony whereof I have hereto pu my hand this 15th day of February, 1907.

LEE C. SHARP Witnesses IsAAo B. OWENS, ETHEL MOLAUGHLIN.

C(pies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, I). O.

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