US2981649A - Coaxial cable splicer - Google Patents

Description

April 25, 1961 G. E. METCALF, JR

COAXIAL CABLE SPLICER Original Filed March 28, 1958 2 Sheets-Sheet 1 INVENTOR. GUY E. METCALF, JR. WW

ATTORNEY Y W 7?- Wm AGENT i -Qa Aprll 25, 1961 G. E. METCALF, JR 2,981,649

COAXIAL CABLE SPLICER Original Filed March 28, 1958 2 Sheets-Sheet 2 E TOR.

2 INV N 33 GUY E. METCA F, JR.

BY WW...

ATTORNEY I AGENT United States Patent COAXIAL CABLE SPLICER Guy E. Metcali, Jr., Cedar Vale, Kans. (193311 AACS Sq., APO 864, New York, N.Y.)

Original application Mar. 28, 1958, Ser. No. 724,789. Divided and this application July 27, 1959, Ser. No. 829,940

g 4 Claims. (Cl. 154-432) (Granted under Title 35, US. Code (1952), see. 266) individual lengths of coaxial cable, andthis application for Letters Patent is a division of my copending application Serial No. 724,780, filed on March 28, 1958, now Patent No. 2,923,806.

In the utilization of coaxial cable for remoting video information, a number of one-thousand foot cable lengths connected together are required. The usual connectors on each end of these cable lengths do not provide a watertight connection, resulting in a poor signal to noise ratio as well as an excessive amount of alternating current hum on the video signals supplied to the remote indicator. Moreover, it was normally found to be practically impossible to dry out collection of moisture in the coaxial cable braid between the outer jacket and the dielectric. The latter resulted in a shorting-out of the wet cable connections effecting an unreliable video signal received at the remote site, as for example, in radar ap proach controls and ground-controlled approach (GCA) aircraft landings. The coaxial cable splicer of the present invention has been developed in order to eliminate the above described problems.

It is an object of the present invention, therefore, to provide a unique means of connecting individual lengths of coaxial cable.

it is a further object of the invention to provide a novel cable splicer device for waterproofingv the connection between individual lengths of coaxial cable.

A still further object of the invention is to utilize a device for joining cable lengths together through the application of constant pressure and heat.

Another object of the invention resides in a mechanism for joining cable lengths by the application thereto of external material.

A still further object of the invention is in a system for joining the ends of cable lengths through constant pressure controlled by a constant weight acting through a piston.

An additional object of the invention resides in a cable splicer device that eliminates the shorting out of wet cable connections at inappropriate moments making for an inoperative signal received at a remote site.

Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawings, in which like reference characters refer to like parts in the several figures. I

Fig. 1 is an isometric view of the cable splicer of the present invention, illustrating the splicing and molding sections in assembled condition.

Fig. 1a is a bottom perspective view of the heater assembly unit utilized with the inventive cable splicer of 2,981,649 Patented Apr. 25, 1961 Fig. 1, illustrating additional details of the combination heater and upper mold assembly.

Fig. 2 is a top view of the cable splicer of Fig. 1, illustrating additional details of the splicing and molding sections with the cable lengths to be spliced and molded in mounted condition.

Fig. 2a is an enlarged somewhat top perspective view of the molding section of the cable splicer of Fig. 1.

Fig. 3 is a cross-sectional view taken about on line 3 3 of Fig. 2 of the cable mold bracket assembly illustrating additional details of the cable mold clamps and bracket utilized with the present invention.

Figs. 4, 4a, 4b and 4c, respectively, are schematic, partly broken away views representing the various conditions of the cable utilized with the cable splicer of the present invention after the molding thereof has been accomplished.

Fig. 5 is a schematic view of the wiring diagram that may be utilized with the cable splicer of the instant inven tion in order to perform the necessary splicing and molding operations.

Before the initial cable splicing operation is accomplished, the cable sections to be spliced must be appropriately prepared in various stages before being mounted L in the cable splicer of the invention. After a selected pair of cable sections are prepared in the manner described in detail in my copending. application Serial No. 724,780, filed March 28, 1958, both of said cable sections are then mounted in the cable splicer assembly and spliced in the manner described in the aforesaid copending application.

With particular reference to Figs. 1 and 2 of the drawings, the cable splicer assembly of the present invention preferably includes an aluminum case :1 having a Bakelite or other hard plastic top cover '2 and an aluminum bottom cover plate 3. Positioned on the top cover plate 1 is the rod-mounting bracket 4, right and left- hand splicer clamps 55, 56, brass rods 27a and 27b and microswitch 12 utilized for accomplishing the splicing of two cable sections in the manner previously described in detailin copending patent application Serial No. 724,780, filed March 28, 1958. 7

Referring again to Fig. l and also to Figs. 2 and 2a of the drawings, the coaxial cable mold bracket of the present invention is indicated at 5 as mounted on the top cover plate 2 on the opposite side thereof from the previous mentioned mounting bracket 4 as by means of the screws 25. Said mold bracket 5 may consist of a one-eighth A3) inch flat steel plate having one edge thereof formed with a pair of spaced upright supports 50 adjacent each end thereof for supporting a lower steel or brass cable mold end clamp 44 thereon which lower mold end clamp 44 is silver soldered to said upright supports 5a. in addition, a lower copper cable center mold 20 is silver soldered on an additional pair of spaced upright supports 5b formed on the edge of said mold bracket 5 halfway between upright end supports 5a. Each of said lower mold end clamps 44 is provided with a cable mold clamp yoke assembly 16. As seen clearly in Figs. 1 and 3 of the drawings, said clamp yoke assembly 16 consists of an upper cable mold end clamp 43 comple mentally disposed relative to said lower cable mold clamps 44, a cable mold end clamp yoke 42 silver soldered to said upper cable mold end clamp 43 and a screw 18 and wing nut 19 for retaining or locking said clamp yoke 42 and upper cable mold end clamp 43 soldered thereto in position and clamping the respective ends of the cable lengths 57 to be spliced. As seen clearly in Figs. 2a and 3 of the drawings, coaxial cable mold bracket 5 incorporates a projecting slotted surface indicated generally at Sr: and extending between each respective pair of upright supports 5a and 5b. Each cable mold end clamp yoke 42 tapers downwardly into a portion 42a (note Fig. 3) terminating in a narrowed bottom portion 42b extending at right angles thereto into the open space between respective upright supports 5a. Each screw 18 is affixed at one end as by silver soldering to said narrowed bottom portion 42b and extends through a respective slot of the slotted surface 5c at its other end where it is engaged with wing nut 19 for appropriate adjustment and clamping. A similar projecting slotted surface 5d extends between the upright supports 5b of the lower cable center mold 20 with an identical screw and nut 18, 19 for mounting the center cable mold clamp yoke 17. Said cable mold clamp yoke '17 is seen clearly in Figs. 1 and 3 of the drawings and incorporates a pair of spaced projecting somewhat arcuate fingers 17a on the upper end thereof which fingers 17a are adapted for engagement with the upper center mold 20a which upper center mold 200 is silver soldered to the combination heater and upper mold assembly unit 15. Said combination heater and upper mold assembly unit consists of a heater assembly 15a incorporating a heater cartridge 33, and an upper mold assembly 15b consisting of a cylinder'15c,- piston rod 14 for insertion at its lower end into said cylinder 15c, and a weight 13 which may consist of a tin can filled with lead mounted on the upper end of piston rod 14 for purposes to be hereinafter explained in detail. In addition, an electrical cord 51 is attached at one end to the heater cartridge 33 of heater assembly 15a and extends to an opening (note Fig.1) in top cover plate 1 for connection in circuit with transformer 38, as shown in Fig. 5 of the drawings. Moreover, a push button switch 28 and a toggle switch 29 are mounted on top cover plate 2 (Fig. l) and are utilized, respectively, to energize the welding circuit as set forth in the aforesaid parent copending application Serial No. 724,780 and the heater assembly unit (note Fig. 5).

After the two cable ends to be spliced have been prepared, the center conductors 61 thereof are than mounted and welded in the cable splicer assembly as previously noted with reference to the aforesaid copending application Serial No. 724,780. After welding is completed, the wires are removed from the fixed and movable clamps 55, 56 (Fig. 2) and the welded area is scraped lightly with a knife. At this time, the wire braid 59a that has been previously fanned out is checked to ensure that it is still perpendicular to the cable 57. Next, the spliced cable 57 is placed in the molding section of the inventive splicer with the exposed center conductor 61 in the center cable mold and adjacent end portions 58 in oppositely disposed lower cable mold end clamps 44. One upper cable mold end clamp 43 and the cable mold clamp yoke 42 soldered thereto is complementally engaged over the top of one end portion 58 of the spliced cable and tightened securely in place. The oppositely disposed uppercable mold end clamp 43 and cable mold clamp yoke 42 is loosely complemental'ly engaged over the top of the other end portion 58 of the spliced cable and this end of said cable pulled with a pressure of approximately pounds to ensure proper centering of the exposed center conductor 61 in the lower center cable mold 20 at which point, upper cable mold end clamp 43 and cable mold clamp yoke 42 on the latter end are securely tightened in place. It is noted that it is most important that correct centering of the exposed wire or center conductor 61 be ensured, since any deviation of the conductor from the correct center position changes the characteristic impedance at that point and results in reflections of the primary signals on the line and degeneration of the display on the remote indicator. After the spliced wire or center conductor 61 has been correctly fastened in the molding section as described above, the upper cable center mold 20a of the combination heater and upper mold assembly unit 15 is placed over said exposed wire of center conductor 61 in the lower center cable mold 20 and securely fastened in place by means of the center mold clamp yoke 17. The upper mold assembly indicated at 15b in Fig. 1 consists of a cylinder 15c containing a supply of prepared polyethylene that extends approximately one half inch below the top of said cylinder 15c. Piston rod 14 is inserted into cylinder 15c and applies continuous pressure on the prepared polyethylene therein by means of the weight 13. Thereafter, when heater toggle switch 29 is actuated to energize heater assembly 15a and thereby heat the cylinder 150, the prepared polyethylene material therein is forced out through the extrusion hole 15d (note Fig. la) into the lower cable center mold 20 to cover the center conductor 61. The weighted upper mold assembly 15b is not removed until a slight amount of polyethylene has extruded out both ends of said cable center mold 20 and allowed to cool. It is noted that it is necessary to cut off the heater switch 29 after a few seconds only if the molding operation is started at room temperature. If cooler temperatures prevail, however, switch 29 is left on for a longer period. After the extruded polyethylene material has cooled, the weighted piston rod 14 is removed from the cylinder 15c by twisting the weight 13 in a circular motion and pulling upwardly. The combined heater and upper mold assembly unit 15 and cable mold end clamps 43 and yokes 42 are removed. The cable 57 is then removed from the mold section and the spliced section, center condoctor 61, examined for air bubbles, poor seal or misalignment of the center conductor and, if so, the entire spliced area is cut out and the above described procedure is repeated.

Referring particularly to Figs. 4, 4a, 4b and 4c of the drawings, a spliced cable is shown generally at 57 and consists of two cable sections each having an outer cable jacket 58, an exposed cable shield 59 with a fanned section 59a, a polyethylene dielectric 60 and a center conductor 61, the latter having been molded together as a single unit in the manner previous described. In addition, excess polyethylene material indicated at 61a has been formed on the surface of dielectric 60 during the molding process described above. This excess is neatly trimmed 01f by a sharp knife. Next, one of the loose cable shields 59 is slid back in its proper position over exposed dielectric 60. Said cable shield 59, which should be as snug as possible against dielectric 60 with fanned out section 59a still braided, is held in place by wrapping with approximately twenty turns of No. 30 wire indicated at 62 in Fig. 6a on the drawings. The other loose cable shield 59 is likewise slid back into its proper position over the remaining portion of exposed dielectric 61 in overlapping and tight relation to said first cable shield and then securely fastened with approximately twenty turns of No. 30 wire as seen at 62 in Fig. 6b. A slight amount of soldering paste is applied to the overlapped portion of said shields. Finally, after preheating a substantial amount of solder is applied'to the overlapped portions of cable shield 59 with said overlapped portions being twirled very rapidly. Precaution should be taken not to attempt a perfect solder connection on the entire overlapped portions since excessive heat will melt the polyethylene and thus destroy the impedance characteristics of cable 57. The spliced area of cable 57 is then wrapped with a one-third overlap layer of vinyl tape with the tape overlapping outer cable jacket 58 one inch on each end as illustrated at 63 in Fig. 4c of the drawings. This taped area is then dipped in liquid vinyl, allowed to dry for at least one hour, and then redipped. It is noted that should the liquid vinyl thicken because of exposure to air, it may be thinned with any appropriate paint thinner.

Thus, a new and unique cable splicing and molding device has been developed by the present invention wherein the previously spliced center conductor ends of two preselected cable sections are inserted in a mold section and molding material applied thereto.

I claim: v

1. In a. cable splicer machine for splicing cable seetions comprising an outer case having a top cover insulated plate, a bottom cover plate and a power transformer positioned within said outer case in depending mounted condition relative to the inside of said cover plate, a cable mold bracket mounted on said top cover plate, said cable mold bracket having a pair of upright lower mold end clamps adapted to receive the opposite ends of previously welded cable sections and a lower center mold adapted to loosely receive the welded area of said cable sections, each of said lower mold end clamps having a cable mold clamp yoke assembly adapted to clamp said opposite ends of said cable sections in each of said lower mold end clamps, and a combination upper mold and heater assembly unit in complemental engagement with said lower center mold retaining therein the welded area of said cable sections, said upper mold and heater assembly unit comprising an upper mold assembly consisting of a relatively elongated cylinder open at the bottom end thereof and adapted to contain a supply of polyethylene material and incorporating an upper center i mold integrally formed in transverse relation with the bottom end of said cylinder and in complemental engagement with said lower center mold and having a relatively small bottom extrusion hole communicating with the interior of said cylinder, a heater assembly integrally aflixed adjacent said cylinder and containing a heater cartridge in circuit with said power transformer adapted to heat said supply of polyethylene within said cylinder, and a slidably mounted, relatively elongated weighted piston closing the upper end of and positioned within said cylinder applying continuous pressure on said supply of polyethylene material forcing said polyethylene material through said relatively small bottom extrusion hole outwardly in opposite directionsthroughout said lower center mold to coat the welded area of said cable sections therewith on energization of said heater cartridge by said transformer.

2. In a cable splicer device for splicing the exposed ends of a pair of cables, means for molding the spliced ends of said cable comprising a lower cable mold unit having a pair of spaced oppositely disposed and longitudinally aligned, lower cable mold end clamps for receiving the unexposed end portions of said cables and a center cable mold intermediately disposed between said pair of lower cable mold end clamps for receiving the exposed spliced ends of said cables disposed inwardly of said end portions, means for securely fastening said spliced cable ends within said lower cable mold comprising an upper mold unit in complemental engagement with said lower cable mold and means for retaining said upper mold unit in complemental engagement with said lower cable mold comprising a cable mold clamp yoke having a pair of spaced projecting fingers on the upper end thereof in engagement with said upper mold unit, and a combination heater and upper mold assembly including an upright cylinder integrally formed with said upper mold unit and incorporating a supply of plastic material integrally formed adjacent to said heater assembly as a single unit, said cylinder having a weighted piston rod for insertion therein in continual contact with the upper surface of said plastic material and closing the upper end of said cylinder, said upper mold unit having an extrusion opening in the bottom surface thereof in communication between the interior of said cylinder and said lower cable mold unit for receiving said plastic material under action of said weighted piston rod and depositing the same in said lower cable mold unit outwardly in opposite directions over the exposed spliced ends of said cables.

3. In a cable splicer device for splicing the exposed ends of a pair of cables as in claim 2, said lower cable mold unit comprising a coaxial mold bracket consisting of a flat plate having one edge thereof including a first and a second pair of'spaced upright elements formed adjacent opposite sides thereof, each supporting one end of a lower metallic mold end clamp integrally formed therewith, a third pair of spaced upright elements formed along one edge of said mold bracket intermediate said first and second spaced upright elements, a lower cable center mold integrally formed on said third pair of spaced upright elements and extending in alignment with said pair of lower cable mold end clamps and a cable mold clamp yoke assembly provided for each of a pair of lower mold end clamps and each consisting of an upper cable mold end clamp complementally disposed relative to said lower mold end clamp and a cable mold end clamp integrally formed relative to said upper cable mold end clamp, and adjustable locking means for positively looking said clamps relative to said coaxial mold bracket and the respective ends of said spliced cable comprising a cable mold end clamp yoke for each of said clamps, each of said cable mold end clamp yokes having a portion tapering downwardly and terminating in a narrowed bottom portion extending transverse thereto into the space between a respective pair of said spaced upright elements and adjustably positioned locking means rigid-1y attached at one end to said narrowed bottom portion and means releasably holding the other end thereof to said bracket.

4. In a splicer device for splicing the exposed ends of a pair of cables, means for molding and waterproofing the spliced ends of said cables comprising a coaxial cable mold bracket having a pair of projecting slotted end surfaces extending outward-1y from and along one edge thereof on opposite sides of said bracket and a projecting slotted central surface extending outwardly of said one edge intermediate of, and parallel to, said pair of slotted end surfaces, a pair of spaced upright end supports extending transverse to said slotted surfaces on each side of said central projecting surface, a relatively elongated, lower cable mold end clamp silver soldered on each of said pair of upright end supports supporting opposite ends of said pair of spliced cables and a relatively short, lower cable center mold silver soldered on said pair of upright central supports in longitudinal alignment with said pair of end supports and supporting the exposed ends of said pair of spliced cables in cradled relation therein, an upper cable mold end clamp yoke mounted on and integrally formed with each of said cable mold end clamps, each of said lower cable mold end clamps incorporating means for clamping said upper end clamp yokes and the upper cable mold end clamps integrally formed therewith in complemental, engaging position on said lower end clamps comprising a lower portion tapered downwardly into a bottom, narrowed yoke portion extending downwardly between said spaced upright end supports on each end of said cable mold bracket to a portion extending at right angles thereto into the open space between said pair of spaced upright end supports and parallel to said pair of projecting slotted end surfaces, an elongated clamp screw aflixed at one end thereof to each of said bottom, narrowed yoke portions and extending downwardly at the other end thereof through said projecting slotted end surfaces into clamping engagement with a wing nut, and a combination heater and upper mold assembly unit comprising a heater assembly electrically interconnected with and under control of a power transformer and a main heater switch and an upper mold assembly including a main housing mounted adjacent to and in continuous contact with said heater assembly and containing a supply of plastic ma terial, an upper cable center mold integrally afiixed to said main supply housing in transverse relation thereto in complemental clamping engagement with said lower cable center mold and having a relatively reduced extrusion opening incorporated in the bottom surface thereof and in communication with the interior of said integrally formed main supply housing and a weighted 7 plunger rod slidably engaged within said main supply subsequently to heating and liquefying said plastic mahousing in contact with the plastic material contained terial by means of said heater assembly. 6.111 a l p c9ntmuus pressure Q P forcmg sald References Cited in the file of this patent plastlc matenal m a downward dlreotlon outwardly 7 through said communicating extrusion opening into said 5 t V UNITED STATES PATENTS lower cable center mold and in surrounding, adhering re- 1,583,815 Trebes May 11, 1926 lation to the exposed ends of said pair of spliced cables 2,312,652 Komives et a1. Mar. 2, 1943

Claims (1)

1. 2. IN A CABLE SPLICER DEVICE FOR SPLICING THE EXPOSEDD ENDS OF A PAIR OF CABLES, MEANS FOR MOLDING THE SPLICED ENDS OF SAID CABLE COMPRISING A LOWER CABLE MOLD UNIT HAVING A PAIR OF SPACED OPPOSITELY DISPOSED AND LONGITUDINALLY ALIGNED, LOWER CABLE MOLD ENDS CLAMPS FOR RECEIVING THE UNEXPOSED END PORTIONS OF SAID CABLES AND A CENTER CABLE MOLD INTERMEDIATELY DISPOSED BETWEEN SAID PAIR OF LOWER CABLE MOLD END CLAMPS FOR RECEIVING THE EXPOSED SPLICED ENDS OF SAID CABLES DISPOSED INWARDLY OF SAID END PORTIONS, MEANS FOR SECURELY FASTENING SAID SPLICED CABLE ENDS WITHIN SAID LOWER CABLE MOLD COMPRISING AN UPPER MOLD UNIT IN COMPLEMENTAL ENGAGEMENT WITH SAID LOWER CABLE MOLD AND MEANS FOR RETAINING SAID UPPER MOLD UNIT IN COMPLEMENTAL ENGAGEMENT WITH SAID LOWER CABLE MOLD COMPRISING A CABLE MOLD CLAMP YOKE HAVING A PAIR OF SPACED PROJECTTIN FINGERS ON THE UPPER

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