United States Patent Inventor Appl. No.
Filed Patented Assignee Frederic C. Doughty Valley Forge, Pa.
Oct. I2, 1970 Nov. 23, 1971 Burroughs Corporation Detroit, Mich.
MULTICONDUCTOR COMPOSITE BELT AND METHOD OF FABRICATING IT 5 Claims, 5 Drawing Figs.
51 lnt.Cl noun/04 so FieldofSearch 174/70c,
97,117 R, l 17F, ll7 FF; 339/17 F, 176 MF,61 R; 29/624; 156/52; l/55 References Cited UNITED STATES PATENTS 3,339,010 8/1967 Brentrup Primary Examiner-E. A, Goldberg Attorney-Carl Fissell, Jr.
ABSTRACT: A composite electrical cable in the form of a belt, constructed by interlocking two half belts.
PATENTEDNUV 23 ISII INVENTOR. FREDERIC C. DOUGHTY ATTORNEY BACKGROUND OF THE INVENTION This invention relates generally to electrical conductors and particularly to a multiconductor cable or belt and to the method of fabricating it. While not limited thereto, the invention finds special application for making electrical connections in the cabinets and between the cabinets of computing systems.
Multiconductor cables for computing systems, for example, generally contain a large number of densely packed wire conductors which must be separated at their end regions and routed to their connecting points. However, an inexpensive method of separating the conductors in a desired order and terminating them to some form of connector is not presently known. In many cases, the cost of stripping the conductor ends of the multiconductor belts and terminating them to connectors is greater than the initial cost of the multiconductor belt itself.
Stripping of the insulation from the belt conductors is accomplished in various ways. In one method, a pair of knife blade edges are caused to approach one another through the insulation through the thin dimension of the belt until the level of the bare conductor wire is reached by each knife blade edge. Then, with the belt held in place, the knife blades are moved together in the appropriate direction to strip the required amount of insulation from the conductor ends. In another method, the insulation is melted by the application of heat so as to expose the bare conductors. In either of these stripping methods, the numerous miniature hairlike wires are released from the restraint of the insulation and sometimes become crossed or tangled. This necessitates considerable handwork to separate and unravel the conductor wires in the process of preparing them for soldering. Also, because of the small diameter and delicate nature of the conductors, they are not adaptable to mass soldering techniques and must be soldered in place individually.
SUMMARY OF THE INVENTION An object of the invention is to provide a multiconductor belt which avoids the above-mentioned difficulties.
Another object of the invention is to provide a multiconductor belt whose conductors can be exposed for connection purposes without the application of heat or cutting operations.
A further object of the invention is to provide a multiconductor belt whose conductors can be exposed for making connections, and with each conductor fixed in position relative to adjacent conductors so as to afford ease in identification, handling and soldering.
Another object of the invention is to provide a multiconduc tor belt which is simple to use and inexpensive to manufacture.
Still a further object of the invention is to provide a novel method of fabricating a multiconductor belt.
In accordance with the above objects and considered first in one of its broader aspects, a multiconductor composite belt according to the invention may comprise two interlocked half belts. Each half belt may comprisean elongate base of electrical insulating material, a plurality of spaced elongate ridges of electrical insulating material projecting from the base, and a plurality of elongate conductors each carried by one of the ridges. In the composite belt, each ridge of each half belt interlocks with at least one ridge in the other half belt.
In one of its broader aspects, the method of the invention may comprise the steps of fonning two elongate half belts of electrical insulating material with each half belt having interlocking elastic portions along the inner side of the half belt, positioning a group of conductors along the inner side of at least one of the half belts, and pressing the two half belts together until their interlocking portions interlock.
The invention will be more clearly understood when the following detailed description of the preferred embodiment thereof is read in conjunction with the accompanying drawing which is described below.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary isometric exploded view of a multiconductor composite belt constructed in accordance with the invention.
FIG. 2 is a fragmentary isometric view showing the composite belt in the assembled condition.
FIG. 3 is a fragmentary front view illustrating the composite belt connected to a printed circuit board.
FIG. 4 is a plan view, with part broken away, paratus shown in FIG. 3.
FIG. 5 is a sectional view taken along line 5-5 of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to the details of the drawing, a multiconductor composite belt 10 consists of two half belts I2 and I4. The half belts l2 and 14 are similarly constructed, therefore, a detailed description will be given of only one of them.
The half belt 12, for example, comprises an elongate base 16 of electrical insulating material which is provided with a number of spaced elongate conductor-carrying ridges I8 and end ridges 18c on its inner side. In the present embodiment of the invention, the ridges l8 and 18c are parallel. The ridges 18 and l8e of the half belt 12 are constructed so as to interlock with the ridges 18 of the half belt 14 when the two half belts l2 and I4 are pressed together. The ridges I8 and I8e may be given various forms for interlocking purposes, however, it is preferable that each ridge l8 and 18c be shaped in the form of a dovetail or partial dovetail, respectively, as shown.
Each ridge 18 is provided with an elongate groove 20 in which is secured an elongate conductor 22. The grooves 20 are so located that almost, but not quite half of the circular surface of each conductor 22 is exposed. Elongate grooves 24 formed in the base 16 between adjacent ridges I8 and mate with the exposed portions of the conductors 22 in the half belt 14.
The half belts l2 and 14 may each be constructed as a molded unit in which the conductors 22 are set in the grooves 20 in the molding process or, alternatively, the half belts I2 and 14 may be constructed by first forming the bases I6 and 26 and then pressing the conductors 22 into the grooves 20. The'composite belt 10 is then formed by aligning the two half belts l2 and .14 so that the ridges 18 of the half belt 14 are up posite the spaces between the ridges 18 and l8e of the half belt 12 and then pressing the two half belts l2 and 14 together until their ridges l8 and 18c interlock. For this purpose, it is required that the ridges l8 and I8e be sufficiently elastic so as to facilitate their interlocking. Considering, as an example, a composite belt 10 having a thickness of 0.035 inch and conductors 22 of 0.012 inch diameter spaced on 0.025 inch centers, Teflon is one example of an electrical insulating mate rial which is suitable for constructing the bases 16 and 26, and which is sufficiently elastic to allow the interlocking ridges l8 and 18 to interlock.
To electrically connect the composite belt 10 to an associated circuit member, such as a printed circuit board 28, the half belts 12 and 14 are separated for the required length, as shown in FIG. 3, and then held to the opposite sides of the printed circuit board 28 with a heat clamp or other suitable device, not shown, so that the conductors 22 of the half belts I2 and 14 may be mass-soldered to pretinned conductors 30 of the printed circuit board 28. For purposes of simplicity, the solder has been omitted from the drawing. The ability of the Teflon bases 16 and 26 to withstand high temperatures facilitates the soldering operation. Heat for soldering may be applied from heating elements in the heat clamp or through the use of infrared beams, or other suitable source of heat.
l. A multiconductor composite belt comprising two interlocked half belts, each half belt comprising an elongate base of of the apelectrical insulating material, a plurality of spaced elongate ridges of electrical insulating material projecting from said base, and a plurality of elongate conductors each carried by one of said ridges, each ridge of each half belt interlocking, in the composite belt, with at least one ridge in the other half belt.
2. A multiconductor composite belt according to claim 1 wherein the major portion of each conductor is embedded in the associated ridge so that the remaining minor portion of said conductor is exposed, in the half belt, along the length of the conductor.
3. A multiconductor composite belt according to claim 2 wherein each ridge carrying a conductor has a dovetail cross section and each space between adjacent ridges on each half belt has a mating dovetailed form to interlockingly receive a conductor-carrying ridge on the other half belt.
4. The method of fabricating a multiconductor belt comprising the steps of forming two elongate half belts of electrical insulating material with each half belt having interlocking elastic portions along the inner side of the half belt, positioning a group of conductors along the inner side of at least one of said half belts, and pressing the two half belts together until their interlocking portions interlock.
5. The method of fabricating a multiconductor belt comprising the steps of fonning two elongate half belts of electrical insulating material with each half belt having elongate spaced parallel interlocking elastic ridges along the inner side of the half belt, applying a group of wire conductors to each half belt by embedding the major portion of each wire conductor in a separate one of said ridges so that its remaining minor portion is exposed along the length of the conductor, positioning the half belts so that the ridges of one half belt are opposite the spaces between the ridges of the other half belt, and
pressing the two half belts together until their ridges interlock.
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