US1563234A - Flexible nonmetallic electric conduit - Google Patents

Description

H. M. SHORT FLEXIBLE NONMETALLIC ELECTRIC C ONDUIT Nov. 24 1925.

Filed Jan. 30, 1922 Fig". 2..

R C T N E V m Patented Nov. 24, 1925.

PATENT HENRY M. SHORT, OF PENN YAN, NEVJ YORK.

FLEXIBLE NONMETALLIC ELECTRIC CONDUIT.

Application filed January 30, 1922.

To all whom it may concern:

Be it known that I, HENRY M. SHORT, a citizen of the United States of America, residing at Penn Yan, Yates County, New

York, have invented a new and useful Flexible Nonmetallic Electric Conduit, of

which the following is a specification.

The main object is to provide at a reasonable cost, a substantial tube which will meet all of the requirements of the fire underwriters. I have also sought to provide a construction which can be made on simple and relatively inexpensive machines. Incidently, I have sought to make a single wall tube which although very flexible is substantially non-extensible and noncollapsible, and yet, may be readily fished.

Figure l is a side view of a fragment of a conduit embodying improvements of my invention showing one end uncoated, split and spread out.

Fig. 2 is a fragmentary transverse section on an exaggerated scale on the plane of the line 22 of Fig. 3.

is a longitudinal sectional view on an enlarged scale.

The fabric of the tube is made up of a series of longitudinal cords 5 surrounded by cii'cuintcrentiuliv extending ribs 6, and a tie 1 1 member which is knitted about the cords and ribs. These'members are assembled in a special form of knitting machine so that the knitted loops draw the tension cords into close contact with the ribs.

Preferably all of the members are of t *isted fibre which can be readily handled in a knitting machine. These members When the tension is properly adjusted sink into each other at the points of crossing so as to produce a con'irmratively smooth interior surface which will not interfere With fishing the electric wires.

The ribs may conveniently be in the form of a continuous coil surrounding the tension Serial No. 532,659.

members which are also preferably continuous. The ribs may be somewhat larger and stiffer or more resilient than the tension members so as to give a maximum rigidity against collapse.

By having the tension members arranged all on one side of the ribs (as distinguished from being interwoven with the ribs), I secure a maximum degree of flexibility. Although it is desirable to use longitudinal tension members such as 5, it should be understood that the knitted fabric itself affords substantial longitudinal tensional strength, particularly when the fireproof and waterproof coating 8 has been applied. This coating is preferably applied in the form of a hot liquid which impregnates the outer Wall and fills up all the outer spaces between the members of the tube. The tube is preferably knitted tightly enough so as to prevent the liquid composition from passing through to the interior.

I claim:

A sin le wall, flexible, non-metallic electric conduit comprising longitudinal tension cord members of fibrous fleizible material, a

stiffer continuous helical coil member formed of fibrous material, a tie member tightly knitted about said coil and cord members and formed of soft fibre and having loops tightly holding portions of said tension cord members between the adjacent turns of said coil member, said members being embedded in each other at the points of contact, parts of said loops and said tension cord members and said coil member forming a smooth inner surface of said conduit, and a fireproof and waterproof composition covering the outside of said conduit and impregnating and stiffening the outer parts of said members and securing said tension cord members to said helical. coil member.

HENRY M. SHORT.

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