US154760A - Improvement in pipe-elbows - Google Patents

Description

UNITED STATES PATENT OFFICE.

GEORGE LUPTON, OF INDIANAPOLIS, INDIANA.

IMPRovEMENT IN PIPE-ELBows.

Specication forming part of Letters Patent No. 154,760, dated September 8,1874; application filed l January 6, 1874.

To all whom it may concern:

Be it known that I, GEORGE LUPToN, of Indianapolis, in the county of Marion and State of Indiana, have invented certain Improvements in th e Construction of Pipe-Elbows from Sheet Metal, of which the following is a specication The nature of my invention consists in providing a smooth curved pipe of uniform thickness throughout, and composed of a single uncrimped and uncut piece of sheet-iron. I have contemplated various processes by which such a curved pipe may be produced from such a single piece of sheet-iron, and I do not propose to restrict myself to the particular mode hereinafter described, for my invention includes every curved pipe possessing` the abovestated peculiarities, no matter how produced.

A, Figure l, is a plan of a sheet of variable thickness for one elbow. vA1 is a transverse section of the same sheet, showing double thickness in the center, and tapering gradually to the ordinary thickness at the edges. A2, Fig. 2, shows the same sheetformed into a straight trough, of U shape, preparatory forl the stretching and curving process. YThis straight trough is now passed between pressure-rollers, one ofwhich is concave and theV other convex at the periphery. These rollers stretch the trough lengthwise in the middle, gradually reducing the thickness of themetal from the center to the edge to a uniform gage, and thereby curving it into the shape shown at B, Fig. 3. This curved trough is now placed upon a curved mandrel, whose diameter corresponds with the interior of the desired elbow, and by means of curved dies its edges are swaged or pressed into the concave radius of the mandrel, where these edges are securely united by rivets or seam, in the usual manner.

I am aware that in the manufacture of spouts for coffee-pots made of sheet metal the practice has been to first make a complete straight pipe, and give to it the requisite slight curve at one end by bending it over a flexible mandrel. must necessarily be stretched and thinned out along the convex side of the bend, and, as the pipe was originally made .of metal of even thickness, the curve will, when finished, be of variable thickness. Besides, in practice, the concave side of the bend always becomes solnewhat crimped. Persons skilled in the art of metal-working will at once recognize the impossibility of making a curved-pipe such as I have described by such a process. I am also aware that cast pipes of soft metal have been made in straight sections with thickened portions, by thinning out which the pipe was curved, and its walls left of uniform thickness throughout.

By the employment of this known process and the machinery used to practice it, it is also impossible to make an elbow of sheetiron such as I have described. Thus, in the state of the art before my invention, there was neither any known means by using which a curved pipe of sheet iron of the character stated might have been made, norwas ever such a pipe made, in fact.

I claim- A stove-pipe elbow made from a blank of sheet-iron having a single longitudinal seam, and formed Without crimping or cutting, thus presenting a smooth surface of uniform thickness throughout when inished, substantially as specied.

GEORGE LUPTON.

Witnesses:

WILLTAM J. McCULLoUGH, LEWIs SHIRELY.

By this rprocess the metal'

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