Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS840766 A
Publication typeGrant
Publication dateJan 8, 1907
Filing dateOct 30, 1905
Priority dateOct 30, 1905
Publication numberUS 840766 A, US 840766A, US-A-840766, US840766 A, US840766A
InventorsEdwin T Greenfield
Original AssigneeEdwin T Greenfield
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
US 840766 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

No. 840,766. PATENTED JAN. a, 1907. E. T. GREENFIELD.





Specification of Letters Patent.

Patented an. s, 1907.

To all whom it may concern.-

Be it known that I, EDWIN T. GREENFIELD, of Kiamesha, in the county of Sullivan and State of New York, have invented certain new and useful Improvements in Tubing, of which the following is a specification.

The invention concerns flexible spirallywound interlocking tubing (preferably metallic) of the character employed as conduit containing an electrical conductor or conductors and as armoringfor electric cables, hose, and the like.

' One of the objects of the invention is to provide an improved article of this character having maximum strength without, however, sacrificing the desirable feature of flexibility.

A further object is to provide a structure which may be manufactured with greater ease and at higher speed than is now possible.

The invention may be expressed in tubing formed of one or more strips bent into successive spirals having interlocking edges, tubing so constructed having been disclosed in several patents heretofore granted to me as, for example, No. 630,503, Figures 1 and 3. The material (usually steel) of which such tubing is constructed is required to be of such thickness as to adapt the same for practical use for the purpose desired. Naturally as the thickness is increased greater difliculty is experienced in the forming operation and more power and slower speed are required. Under the present invention these objections are overcome by employing instead of a strip of the full thickness required two strips each of substantially one-half such thickness, these being formed, as the single strip of full thickness is formed, by bending or winding and lying in spiral form arallel with and adj acent to each other.

I ave found that such parallel and adjacent strips can be given the proper-lateral curvature and also spirally formed tocomplete the tube by the use of less power and at greater speed than are required in the production of tubing from a single integral strip of the full thickness necessary.

Within the scope of this invention the tubing may be formed of a single pair of such half-thickness strips or of two pairs of such strips, as will be understoodupon reference to the patent above named. For the purpose of this disclosure 1 have illustrated the former construction in the drawings, in which Fig. 1 is a side elevation, and Fig. 2 a longitudinal section. I

In the production of this tubing, two (preferably metallic) strips a a, each of approximately one-half the thickness required for the walls of the tube, are laid together, one on the other, and passed simultaneously through a suitable die or dies, whereby they are laterally curved, so that the successive spirals shall interlock while remaining movable relatively to each other to assure flexibility.

After being given this lateral curvature the strips are formed into such successive interlocking spirals in any suitable manner-as,

-' overlying the pair first named being ivena laterally-convex sha e, all as will rea 'ly be understood by one s illed in the art.-

What I claim is 1. A tube consisting of a series ofspiral formed of a plurality of thicknesses of mate rial of equal width and one directly overlying another, the adjacent edges of said splrals,

being interlocked, substantially as set forth. 2. A tube consisting of a series of spirals formed of a plurality of thicknesses of material of equal width and one directly overlying another, said thicknesses being similarly curved transversely and said spirals being interlocked at their adjacent edges, substantial] as set forth.

T is specification signed and witnessed I this 26th day of October, 1905. 1



Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2582797 *Jul 8, 1946Jan 15, 1952Peterson Thomas FMethod of installing helically preformed elements on cables
US5350885 *Apr 8, 1992Sep 27, 1994Monogram Industries, Inc.Armored cable
US5468914 *Oct 19, 1993Nov 21, 1995Monogram Industries Inc.Armored cable
US5557071 *Jun 2, 1995Sep 17, 1996Wpfy, Inc.Armored cable
US5708235 *Sep 11, 1996Jan 13, 1998Wpfy, Inc.Armored cable
US6825418May 16, 2000Nov 30, 2004Wpfy, Inc.Indicia-coded electrical cable
US6906264Jun 17, 2004Jun 14, 2005Southwire CompanyColor-coded armored cable
US7465878Aug 18, 2004Dec 16, 2008Wpfy, Inc.Indicia-marked electrical cable
US7954530Jun 15, 2009Jun 7, 2011Encore Wire CorporationMethod and apparatus for applying labels to cable or conduit
US7977574 *Nov 5, 2008Jul 12, 2011International Business Machines CorporationCable for high speed data communications
US8278554Dec 10, 2008Oct 2, 2012Wpfy, Inc.Indicia-coded electrical cable
US8454785Apr 22, 2011Jun 4, 2013Encore Wire CorporationMethod for applying labels to cable or conduit
US8826960Apr 21, 2011Sep 9, 2014Encore Wire CorporationSystem and apparatus for applying labels to cable or conduit
USRE38345 *Jan 13, 2000Dec 16, 2003Wpfy, Inc.Coded for visual identification by colored patterns; sheath formed of helically interlocked continuous strip of metal or smooth or corrugated continuous tubing
Cooperative ClassificationF16L11/16