US 3777334 A
Plastic strapping generally rectangular in section of the type used to tie bundles of electrical conductors as in my patented strapping apparatus, U.S. Pat. No. 3,633,633 granted Jan. 11, 1972, is extruded with a plurality of parallel, pointed longitudinal ribs, short in height, which prevent the tape from slipping during reverse feed by the gun.
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Description (OCR text may contain errors)
United States Patent 191 Countryman RIBBED STRAPPING  Inventor: Albert J. Countryman, Utica, NY.
 Assignee: Ty-Lok Assembly Systems, Inc.,
 Filed: Sept. 29, 1972  Appl. No.2 293,736
 0.8. CI .L 24/16 PB  Int. Cl 365d 63/00  Field of Search 140/932; 24/16 PB,
24/30.5 P, 17 AP, 305 R  References Cited UNITED STATES PATENTS 3,014,506 12/1961 Crimmins et a1. 140/932 Dec. 11, 1973 3,022,557 2/1962 Logan 24/17 AP 3,141,221 7/1964 Faulls 24/30.5 R 3,371,390 3/1968 Sieglitz i 24/16 PB UX 3,633,633 l/l972 Countryman 140/932 Primary Examiner-D0nald A. Griffin Attorney-Richard C. Sughrue et a1.
3 Claims, 3 Drawing Figures 1 RIBBED STRAPPING,
BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to improvements in the construction of plastic strapping of indeterminate length of the type used to tie electrical conductors in bundles.
2. Prior Art Plastic strapping is in common usage to tie bundles of electrical conductors. There are generally two different types of such strapping. First there are the individual straps with molded heads which require special molds, are wasteful of strapping material, and are commonly applied by hand. Then there is the indeterminate or indefinite lengthnylon strapping having plain flat surfaces as used with strapping guns and locking devices and as disclosed by my prior US. Pat No. 3,633,633granted Jan. 1 l, 1972. This strapping is provided. in rolls and is used asfrequired by the semiautomatic gun.
Problems have arisen in the use of such plain flat sur- One surface .of the strapping, the bottom surface 14 as shown and as used in the patented gun, hasthree identical parallel longitudinal ribs 16. These ribs are spaced about one-fourth, one-half and three-fourths the distance across the width W of the strapping face as shown. The height of each rib Hr is about one-fifth to one-sixth the thickness T so the ribs do not interfere with the function of the apparatus. The configuration of each rib is also identical, it includes a pointed tip 18 between two inclined sides at an included angle of about 60.
In a typical configuration, the tape or strapping is about 0.086 inch wide W, 0.026 to 0.029 inch thick T, the corners are rounded ona 0.008 radius, the ribs are I 0.005 inch high HR, thecenter rib is centered with reface strapping, namely slipping in the reverse feed of the strapping by the gun to tighten or cinch the strap around the bundle of conductors when the lead end of strapping is held in the locking device. Side slipping of the strapping once it is wrapped around the conductors is also'a problem, but a lesser one than that of reverse feed slipping.
SUMMARY OFTI- IE INVENTION Thisinvention resides in providing longitudinal ribs of a desired size and shape on one surface of the strapping to solve the above mentioned problems-Specifically, a plurality of parallel spaced apart ribs are provided. The ribs are spaced apart across the width of the bottom surface of the tape; they are of a height small in relation to the thickness of the tape; and they have. a sharp point.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation of the tape of this invention. FIG. 2 is an end elevation of such'tape. FIG. 3 is a bottom plan view.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Plastic strapping 10 is formed of DYMETROL virgin nylon, a product of E. I. duPont de Nemours Co. of Wilmington, Del. by extrusion of indeterminate lengths, e. g., in rolls to be used as required. The strapping has a tensile strength of about 30,000 psi. The strapping has rounded edges or corners l2 and is approximately three times as wide W as it is thick T. Such strapping would be used, in combination with locking devices to tie bundles of electrical conductors as disclosed in my prior US. Pat. 3,633,633 granted Jan. 11,
gard to the width W and the outer ribs are spaced about 0.02 inch from the edges.
Such tape markedly improves the functional performance of the tie and the gun by the ribs operated upon by the reverse feed mechanism of the gun to provide a uniform tension in the tape during the reverse feed mode. Without the ribs the tape drive would slip on the slippery finish or surface of the tape and it was not'always possible to apply the uniform tension or back feed needed to properly cinch the tape around the bundle or conductors. Moreover, when properly tight ened, the tape ribs will dig into theconductor insulation to prevent the tie from slipping in a direction along the axis of they conductors bound.
I claim: g
1. Plastic strapping for passing around electrical conductors and the like and tying such conductors in a bundle using a separate locking device, such strapping consisting of; an elongated extruded plastic tape substantially longer than that portion thereof used for tying the bundle of conductors, the tape being of electrically insulating material generally rectangular in section having a width about three times the thickness and with rounded corners, and a plurality of parallel longitudinally extending ribs on one surface of the width of the tape and extending'throughout the entire length of the tape, the ribs having a height small in relation to the thickness of the tape, a pointed edge on each of the ribs defined by rib sides, the ribs positioned to lie parallel to one another and approximately equally spaced across the width of the tape.
2. Plastic strapping as in claim 1 wherein there at three identical ribs lying parallel to one another at about one-fourth, one-half and three-fourths the width of the tape.
3. Plastic strapping as in claim 2 wherein the height of the ribs is about one-fifth to one-sixth the thickness of the tape and the pointed edge is defined by the sides of the ribs merging at an included angle of about