US3336554A - Tubular covering and method - Google Patents

Description

Aug. 15, 1967 R. L. HATTON TUBULAR COVERING AND METHOD Filed June 17, 1965 INVENTOR;

RICHARD L. HATTON United States Patent 3,336,554 TUBULAR COVERING AND METHOD Richard L. Hatton, Elmhurst, Ill., assignor to Resinite Corporation, Wheeling, 11]., a corporation of Illinois Filed June 17, 1965, Ser. No. 464,708 Claims. (Cl. 336-209) This invention relates to a tubular covering and method and, more particularly, to a covering for electronic elements such as coils.

It is particularly important to protect electronic elements such as coils against dust, moisture, corrosive effects in general, fungus, etc. Therefore, coils have been equipped with protective coverings, and for that matter, so have a variety of difierent tubular elements. The provision of a useful tubular covering-as for the protection outlined above-constitutes an object of this invention and further, the covering is one that is constructed and installed in an unexpectedly facile manner.

The invention is explained in conjunction with an illustrative embodiment in the accompanying drawing, in which:

FIG. 1 is a perspective view of a delay line coil equipped with the inventive protective covering;

FIG. 2 is an exploded perspective view of the structure of FIG. 1, but in a stage of manufacture prior to that shown in FIG. 1;

FIG. 3 is an enlarged sectional view taken along the line 3-3 of FIG. 1; and

FIG. 4 is an enlarged fragmentary sectional view taken along the line 44 of FIG. 3.

In the illustration given and with particular reference to FIG. 1, the numeral designates generally a delay line coil which includes a coil form or rigid tubular support 11 (see also FIG. 4) on which is wound a plurality of convolutions or turns of conductor wire 12. The ends of the form 11 are equipped with lugs 13 for establishing electrical connections with the wire windings 12. Overlaying the winding 12 between the spaced-apart lugs 13 is a tubular covering generally designated 14 and which can be seen in perspective view in FIG. 2. The covering 14 includes an inner layer 15 and an outer layer 16 (see FIG. 4) which are constructed of resilient plastic film adhesively united. As can be appreciated from FIG. 2, both layers are spirally wound, the spiral Winding of the layer 16 being developed by abutting edges as at 17 while the spiral winding of the inner layer 15 develops butted edges as at 18. The edges 17 and 18 are spaced apart, i.e., the convolutions of the winding 16 overlap the convolutions of the wound layer 15.

As seen in FIG. 2, the covering 14 is longitudinally slit as at 19 and I have found that when the layers 15 and 16 are constructed with the layer 16 slightly thicker than the layer 15, the slit covering 14 tends to form a tight cylinder so as to clamp and envelop the coil form 11 as at 20 in FIG. 3.

As an example of the practice of the invention, I spirally wind a 0.00 thick ribbon of cellulose acetate to provide the inner layer 15 and superpose an offset spirally wound condition a layer 16 of 0.003" thick cellulose acetate. A small amount of acetone is introduced between the layers 15 and 16 causing them to adhere. The thickness of the spirally wound double layered tube thus developed is arranged to be slightly larger than the diameter of the delay line coil to be covered. Thereafter, the tubular covering is longitudinally slit and flexed, i.e., manipulated as at 21 and 22 to open the same for enveloping the coil form 11. Thereafter, the flexing pressure at 21 and 22 is released whereupon the edges of the slit 19 snap together in the overlapped fashion indicated at 20 in FIG. 3. In some instances, I find that the covering can be further advantageously stabilized by introducing acetone between the overlapped portions 20a and 20b to effect a union or a fusing of the two overlapped portions.

A variety of materials of construction may be employed for the layers 15 and 16. Cellulose acetate, as illustrated above, is advantageous because of its low cost and ready fusibility using a common solvent, acetone. However, other resilient plastic film such as ethylene terephthalate may also be advantageously employed. It will also be appreciated that the inner and outer layers may be constructed of dilTerent materials, but in such a case the thicknesses must be adjusted to develop a greater resili ency, i.e., a tendency to convolute, in the outer layer.

While in the foregoing specification, a detailed description of the embodiment of the invention has been set down to explain the invention, many variations in the details herein given may be made by those skilled in the art without departing from the spirit and scope of the invention.

I claim:

1. A tube covering comprising inner and outer layers of resilient plastic film, each layer being spirally wound relative to the axis of said tube, the spiral winding in one layer being offset axially from the spiral winding in the other layer, said layers being adhesively united with the outer layer being thicker than the inner layer, said covering being relatively elongated and longitudinally slit.

2. The covering of claim 1 in which said layers are of the order of a few thousandths of an inch in thickness.

3. An electrical element comprising a wire wound tube form, and a covering thereon, said covering comprising resilient inner and outer each layer being spirally wound relative to the axis of said tube, the spiral winding in one layer being offset axially from the spiral winding in the other layer, said layers being adhesively united with the outer layer being thicker than the inner layer.

4. A method of covering a tubular element comprising spirally winding inner and outer layers of flexible plastic film to form a unitary tube wherein the layer spirals are offset and with the outer layer being thicker than the inner layer, longitudinally slitting said tube, flexing the same transversely to position said slit tube in enveloping relation with said element, and releasing said tube to cause the same to contract into contacting relation with said element.

5. The method of claim 4 in which the longitudinal edges of said tube adjacent the slit or overlap are fused subsequent to said releasing.

LEWIS H. MYERS, Primary Examiner. T. J. KOZMA, Assistant Examiner.

layers of resilient plastic film,

Claims (1)

1. 3. AN ELECTRICAL ELEMENT COMPRISING A WIRE WOUND TUBE FORM, AND A COVERING THEREON, SAID COVERING COMPRISING RESILIENT INNER AND OUTER LAYERS OF RESILIENT PLASTIC FILM, EACH LAYER BEING SPIRALLY WOUND RELATIVE TO THE AXIS OF SAID TUBE, THE SPIRAL WINDING IN ONE LAYER BEING OFFSET AXIALLY FROM THE SPIRAL WINDING IN THE OTHER LAYER, SAID LAYERS BEING ADHESIVELY UNITED WITH THE OUTER LAYER BEING THICKER THAN THE INNER LAYER.

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