US224228A

US224228A - Manufacture of sheet-metal tubing

Info

Publication number: US224228A
Authority: US
Publication date: 1880-02-03
Anticipated expiration: 1897-02-03

Description

D," A, RITG H1B'. facturel of Sheet-Metal Tubing..

,228. Patented Feb. 3, 1880 lUNIT-en v DAVID A. RITCHIE, OF lCHELSEA, MASSACHUSETTS;

.MA'NUFACTURE OF SHEE'TJMETAL TUBING.

SPECIFICATION 4,folmllg part OfInetters PateVNO. '(224,228, `dated `Febrtlal'y 3, 1880.

vApplication led June 6, 1879.

To all whom Muay concern Be it known that I, DAVID A. RITCHIE, ofV

Figure 1 is a perspective view representingV apiece of my improved sheet-metal tubing in the processof construction. Fig. 2 isa section taken on the line of the seam, enlarged. Fig. 3 is a transverse section on the linea: vof Fig. 1.

My invention relates tol that class of sheet.- metal tubing formed by Winding astrip spirally around a mandrel; and'it consists in a spirally- Wound sheet-metal tube in Which one edge of the strip is provided With tongues or projections formedl by punching and striking up the metal Vat suitable intervals, the lother edge of the strip having slits or apertures through which the tongues pass as one edge of the strip overlaps the other in the operation of winding it spirally around the mandrel, the ton gues'or projections bein g'afterward clinched or lattened down on the outside of the seam in such a manner as to hold the edges of the strip rmly together and prevent any liability oftheir separation, thus insuring a tight joint.

To enable others skilled in the art to understand and use my invention, I will proceed to describe the manner in which I have carried it out.

In the said drawings, A represents a strip of sheet lnetal of the required width, which, as it is fed through a machine adapted for the purpose, is Wound spirally around a mandrel or former. One edge, 5, of the strip A, as it passes through the machine, and before it is Wound on the mandrel, is punched by suitable mechanism in such a manner asto strike up tongues orprojections b at short'distances apart, these tongues being left at right angles with the surface ot' thestrip, the holes c from which the metal is punched necessarily'corresponding in size and shape to the tongues. In the opposite edge b of the strip A are punched, at the same dista-nce apart as the tongues b, a series of narrow slits or apertures, d, of such size and shape and in such a-position as to allow the tongues b to pass up through them as the edge b is brought down onto and overlaps the edge 5 (see Fig. l) in the operation of Winding the strip A on the mandrel. A pressure-roll or other suitable device now passes over the seam and clinchesor lattens down thel tongues b onto the outside of the edge b, as seen in Fig. 1, which completes the operation, the two edges of the strip being held rmly and immovably together by the clinched tongues or projections, Which thus form a cheap, simple, and

effective fastening, the several operations ot' winding the strip, striking up the tongues, forming the apertures for their reception, and clinching them down being'all performed during a single passage of the strip through a machine, many advantages being thus presented over the ordinary method of uniting j the edges of a strip of metal by means of separate rivets, which are more costly and involve the expenditure of additional time and labor in their application, besides leaving heads or'projections on the inside of the pipe, which, if of small diameter, is liable to be obstructed by the accumulation of dirt on these projections.

The edge b'of the strip A is provided, as

usual, with 'an oi'set, 7, which causes thejoint to be flush on the inside of the pipe, so as to offer no obstruction.

In practice I prefer to exert a very heavy pressure in clinching down the tongues b, so as to embed or force them into the surfaceA ot' the metal on which they are laid, which causes the under surface of the overlapping edge b ofthe strip to be pressed out, as seen in Fig. 2, into the apertures c, which lie directly beneath, and which are thus iilled up flush, causing the under surface of the edge 5 to present a perfectly smooth and even surface, While the joint is rendered additionally secure.

I do not confine myself to the form or size of the tongues, as they may be of any suitable shape and size.

Sheetme'tal lubin g constructed a-s above described is well adapted for water and hot-air conductors, stove-pipes, speaking-tubes, and various other purposes, and may be galvanized or tinned, if desired, to render the seam or joint perfectly tight.

What I claim as my invention, and desire to secure by Letters Patent, is-

IOO

which one edge of the strip A is provided with to force the corresponding portion of its under 15 tongues or projections b, punched or struck up surface into the apertures c in the piece of therefrom, and the other edge with eorrespondmetal beneath7 from which the tongues are ing slits or apertures d, through which the punched, substantially as and for the purpose 1. A spirztlly Wound sheet-metal tube in l bedded in the outer surface of' the metal, so as tongues pass as one edge of the strip overlaps described.

and is laid down upon the other in the opere- Wit-ness my hand this 4th day of June7 A. 2o tion of Winding, the tongues being afterward D. 1879.

clinched or flattened down to secure the over DAVID A RITCHIE lapping edges of the strip together und form the joint, substantially as described.

2. In a joint forsheet-metal tubing made as described, the tongues b, pressed into or em- In presence of- P. E. TESGHEMACHER, W. J CAMBRIDGE.