US2337373A - Collapsible tubing and method of producing the same - Google Patents

Description

Dec. 21, 1943. CHERNACK 2,337,373

COLLAPSIBLE TUBING AND METHOD OF PRODUCING THE SAME Filed Jan. 29, 1945 Even/ 50:"

ABEL E. CHERNACK V a his aiiiarneya Patented Dec. 21, 1943 COLLAPSIBLE TUBING AND METHOD OF PRODUCING THE SAME Abel E. Chernack, Elmwood, Conn.

Application January 29, 1943, Serial No. 473,999

6 Claims. (01. 138-53) This invention relates to tubing and more particularly to flexible, collapsible tubing for conducting large volumes of heated air under low pressures.

With the development of the airplane to its present large dimensions there has arisen need for flexible lightweight tubing for use in heating the engines, wings and windows. The large volume of heated air required necessitates a tubing of large diameter, which is preferably collapsible for convenient handling, while the temperature range to which such tubing is subjected prevents the use of materials which tend to become hard or brittle and crack at low temperatures, or the use of adhesives which deteriorate with age or soften under heat. However, the tubing is of a construction which is not limited to use with tubing for heating purposes but may be used with tubing for other purposes where usual temperatures are met and the usual materials can be used.

It is an object of this invention to provide a flexible, collapsible tubing constructed of materials which remain unaffected by temperature changes throughout the entire temperature range to which the tubing is subjected in use; which is with a substantially circular cross-section and having the side edges of the strip bent outwardly to form narrow flanges II and I2 at opposite sides of the opening l3. The metal spiral I0 is covered with a spirally wound strip 20 of a fiber glass, textile or other suitable material which is of slightly greater width than the pitch of the spiral l0 and has its opposite edges folded inwardly, as at 2| and 22, adjacent the opposite faces of the strip. In wrapping the strip 20 on the spiral Hi, the inwardly folded edge portions are interlocked as shown in Fig. 3, the width of the strip 20, when applied, being such that the interlocked edge portions of the strip 20 lie on the spiral ID, as shown in Fig. 1.

A binding means 30, of wire, cord or other suitable material, is then applied, being wrapped about the covering strip 20 on the interlocked edge portions in line with the opening l3 in the metal spiral I0 and under suflicient tension to enlarge the opening l3 and draw the interlocked edges of the strip 20 into the trough of the spiral l0. As the interlocked edges of the strip 20 are drawn through the opening l3 they are folded so constructed that the use of adhesives is unnecessary and the tubing remains sealed at all times; which is so constructed that there is no danger of contacting heated metal in the handling of the tubing; which can be manufactured of the diameters and in the continuous lengths desired; and which can be manufactured by a method suitable for rapid and economical production in commercial sizes and lengths. I It is also an object of this invention to provide an improved method of manufacturing tubing of the class described.

In the drawing in which a tubing of preferred construction is illustrated,

Figure l is a perspective view of a short section of tubing constructed in accordance with this invention, a part of the tubing being broken away in order to show more clearly various stages in the manufacture of the tubing;

Figure 2 is a sectional view, drawn to a larger scale, through the seam of the finished tubing; and

Figure 3 is a sectional view, drawn to a larger scale, of the interlocking joint formed in the covering material before the application of the binding wire cord.

As shown in the drawing, tubing in accordance with this invention comprises an inner spiral Hi consisting of a metal strip of a trough-shape about the binding means 30 and then the partial closing of the opening l3, by the resilience of the metal of the spiral l0, serves to cover the binding means with the interlocked portions of the strip 20 and conceal the binding means 30 and cause the spiral Hi to cooperate with the binding means 30 in locking the interlocked edges of the strip 20 in the trough of the spiral Ill.

The binding of the interlocked edges of the strip 20 in the spiral It! prevents the opening of the tubing at the joint in the covering strip 20, and the covering of the metal of the binding means or wire 30 and spiral In by the covering strip 20 insures against contact with heated metal in handling. Tubing thus constructed is of light Weight, even for large sizes, and collapsible so I that long lengths of large size tubing can be conveniently handled or packed for shipment.

What is claimed is:

1. Tubing comprising a, spiral having a troughshaped cross section, a spirally wound covering strip on said spiral, said covering strip having adjacent overlapping edges interlocked, and binding means securing the interlocked edges of said covering strip in said spiral.

2. Tubing comprising a spiral of trough-shaped cross section, a spirally wound covering strip on said spiral, said covering .strip having its edges overlapping along said spiral, and an outer binding means securing the overlapping edges of said strip in the trough of said spiral.

3. Tubing comprising a spiral of trough-algal ins cross section, a spirally wound covering stri on said spiral, said covering strip having overla interlocked edges, and an outer binding means securing said interlocked edges in the trough of means about the overlapping edges of said cover- 7 ing strip under sumcient tension to .rorce the edges of the covering strip into the trough of the spiral.

5. In a method of forming a tubing, the steps 01' forming a continuous spiral from a troughshaped strip, wrapping a covering'strip about said spiral with the edges oi. said covering strip overlapping along said spiral, wrapping a binding means about said covering strip along said spiral, and forcing the overlapping strip edges into the trough of said spiral by said binding means.

8. In a method of forming a tubing, the steps of forming a continuous spiral from a troughshaped strip, wrapping a covering strip about said spiral, interlocking the adjacent edges of said covering strip along said spiral, wrapping a binding means about said covering strip along said spiral and under suiiicient tension to force the interlocked strip edges into the trough oi. said spiral and securing the interlocked strip edges in the trough or said spiral by the joint action of said spiral and binding means.

ABEL E CHERNACK.

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