US2680086A - Manufacture of insulated electric conductors - Google Patents

Description

" www June 15.1954-, D. fr. HoLLmiGsWQRTl-lv ET A; MANUFACTUREbF'INSULATED ELEGTRCCONDUCTORS' Filed Oct. 29, 1951- M Patented June 1,1!954 f UNITED STATES PATENT OFFICE MANUFACTURE 0F INSULATED ELECTRIC CONDUCTORS Douglas Taft Hollingsworth,v Knutsford, and

James Alexander McCleery, Sale, England, assignors to W. T. Glover & Co. Limited, Manchester, England, a British company Application October 29, 1951, Serial No. 253,686

Claims priority, application Great Britain November 14, 1950 3 Claims.. (Cl. 154-225) l 2 This invention relates to insulated electric conformed axially of amember 4. In its extreme ductors of the kind in which the conductor (01' forward position the front end of the ram I is conductors) is enclosed in a metal tube and insudisposed just inside the corresponding end of the lated from it by powder, for instance,magnesia member 4, as will be seen from the drawing. or talc. The invention provides an improved 'i Themember 4, referred to hereinafter as the manufacture carried out by a process in which inner member, cooperates with an outer member the powder is fed into a tube around the con- 5 to form a shaping die for a metal strip of approductor and compressed there. priate width which is fed in a continuous manner In accordance with the invention the insulated through the apparatus. The outer member of conductor (or conductors) is manufactured by a l that die is relatively short as compared with the Continuous process in which the enclosing tube inner member and between the two members is is formed by the gradual transverse bending of a an appropriatelyshaped passage 6 which extends Strip of metal Which iS Continuously moving forforwards in a direction towards the longitudinal. Ward, the bending bringing the edges together, axis of the apparatus and tapers in. width in thaty after which they are united by welding or by l direction. I'heinner member 4 has a rear por-- soldering (soft or hard solder). In this continution 'I having a wall thickness which is gradually ous process the conductor (or conductors) also reduced in the forward direction, an intermediate travels forward with the strip and becomesenportion 3 of uniform wall thickness and a front.

CIOSed in the tube. AS the bending 0f theStrip portion 9, which gradually tapers in thickness; 'proceeds the odgeS of the Strip are brought closer 20 and then continues as a cylindrical portion of.'

and closer together and at an appropriate place uniform Wall thickness,

in the path of the Strip the powder iS fed through The cylindrical intermediate part Il of the inner the gap between the edges of thecurved strip member 4 is surrounded by and spaced from an t0 a place in front of a reciprocating ram- From outer cylindrical casing ill, the upper part of.' that region the powder is pushed forward into which has an aperture II through which insulat the closed part of the strip and consolidated there ing powder for a conductor i2 can be fed inter-i by the ram. The conductor (or conductors) mittently and in appropriate quantities through passes through a hole in the ram. After the a feed hopper I3. Immediately in front of the edges of the strip have been united to form a` casing I0 which cooperates with the intermeclosed tube, the latter ,proceeds forward to a diatecylindrical part 3 of theinner member 4 to reducing die through which it is drawn, underform an elongated cylindrical die, is a member going in the process a reduction of diameter and I4 which cooperates with the adjacent surface 'a further compression of the powder within it. of thefront portion 9 of theinner member 4 to The invention will be described further with provide a forming die which serves to bring tothe aid of the accompanying drawings illustrating gether in abutting relationship the two edges of one form of construction by way of example and a strip passing through the machine.

wherein The forward end of the passage B is in com- Figure 1 is a longitudinal view, partly in secmunication with the passage provided between tion, the figure being largely diagrammatic and theintermediate portion 8 and the casing ID and not drawn to scale, the latter, at its front end communicates with the Figure 2 is a longitudinal view, partly in secpassage provided between the member I4 and tion, of a part of the apparatus shown in Figure 1 thefront portion 9 of theinner member 4. and drawn to an enlarged scale, Immediately in front of the member !I4 is a Figures 3, 4, 5 and 6 are sectional end elevadevice I5 which solders or otherwise joins totions taken on the lines III-III, IV-IV, V-V, 45 gether the abutting edges of the strip to form VI--VI respectively of Figure 2. a complete tube, the diameter of which is reduced In the following description that end of the by drawing the tube through o die I6 by any apparatus shown to the left of the figure is resuitable means. garded as being the rear end and the opposite The ram I has an axially disposed passage I8 end, as the from; end, through which the conductor I2, drawn oir from The apparatus comprises areciprocating rami o bobbrl i9, paSSoS in a Continuous morir-or,

working in a cylinder 2. The ram at its forward entering the passage at the rear end of the ram. part is of reduced diameter and extends for some The conductor passes over aguide roller 20 and considerable distance beyond the end of its cylthen passes in a straight line through the ram I.

inder where it passes into acylindrical passage 3 55 The metal strip which is formed continuously..

into a tube and which encloses the conductor insulated with powder fed in through the hopper I3, is shown at 2l, 22 being a supply bobbin from which the at strip is drawn off, through atension control device 23 and around aguide roller 24. From the latter, the strip 2l passes through a preforming device 25 (see particularly Figure 3) into the front end of thepassage 5. Thede vice 25 has a transversely extending slot 84 through which the strip 2l passes, the slot commencing the shaping of the strip by bending it transversely to its length to facilitate its entry into thepassage 6 where the main part of the transverse bending of the strip is effected and the edges of the strip caused to move towards each other and to provide between those edges a gap which gradually decreases in width in a direction towards the front end of the apparatus. After passing through thedevice 25, the strip passes from below the rear end of the cylinder 2 into the rear end of thepassage 6.

During the passage of the strip through the casing l0, a small quantity of powder is discharged from the feed hopper I3, to the front or workingl end of the ram l which is then positioned (see Figure 2) a short distance to the rear of a port 28 in theintermediate part 8 of theinner member 4. The powder falls from the feed hopper through the aperture l l in the casing ID, through the gap between the edges of the shaped strip (see Figure and through theport 26 into the intermediate part 81. As the ram advances on its working stroke it closes theport 26, and pushes the powder in front of it, the ram continuing to move in the same direction until it enters that part of the tube where the edges of the tube have been joined together by the device I5 which completes the formation of the tube by soldering or otherwise joining the edges together. 'Ihe ram moves with clearance in this part of the tube and presses the powder around the axially disposed conductor and also consolidates the latter. The completed tube 29 and enclosed insulated conductor then pass together through the drawing down die i8 which further compresses the powder insulation. An appropriate form of pulling device indicated by Il may be used for pulling the insulated conductor with its enclosing tube through the die i5.

The reciprocation oi the ram l at an appropriate rate is eilected by a double acting. device 2 comprising a piston working in a cylinder, air under pressure being fed into the cylinder alternately to opposite sides of the piston. The collar 28 on the ram serves as an emergency stop.

The broken line 3B indicates the path of an edge of the strip 2l as the latter passes from thepre-shaping device 25 to the space between the member Hi and thefront portion 9 of the inner member 4l.

The ram l reciprocates in bearings 3l and at its front end, theinner member 4 is formed with a recess 32 which receivespacking material 33 to avoid the risk or" powder reaching the bearings.

What we claim as our invention is:

1. A method of manufacturing a conductor insulated with powder and enclosed in a metal tube, by a continuous process, comprisingl continuously advancing in the direction of its length a metal strip, subjecting the said strip, as it advances, to a transverse bending to eect relative movement of approach of its longitudmai edges and to give to the strip a tubular shape with a gap between its longitudinal edges, continuously advancing a conductor in the direction of its length into the tubular shaped part of the strip, supplying insulating material in the form of powder through the gap between the longitudinal edges of the tubular part of the strip to the interior of that part, joining together the longitudinal edges of the tubular part at a place in advance of that at which the supply of insulating powder takes place thereby forming a complete tube, pushing forward the powder in the tubular part to a place adjacent that at which the longitudinal edges have been joined together and reducing the diameter of the complete tube, thereby compressing the powder therein.

2. An apparatus for the manufacture, as a continuous operation, of a powder-insulated conductor enclosed in a metal tube, comprising a shaping die which transversely bends a metal strip passing therethrough to form an incomplete tube having a gap between its longitudinal edges, a reciprocable ram working in a bore in the shaping die, a device for feeding a powder insulant through the gap in the incomplete tube to the interior of the latter in front of the reciprocable ram, means for closing the gap in the incomplete tube to form a complete tube, the said gap-closing means being mounted in advance of the powder-feeding device, a drawing-down die mounted in advance of the gap-closing means, and means for drawing the complete tube t0- gether with a wire and powder insulant therein through the drawing-down die, reducing the diameter of the tube and compressing the powder therein.

3. An apparatus for the manufacture, as a continuous operation, of a powder-insulated conductor enclosed in a metal tube, comprising a shaping die comprising spaced inner and outer members having their adjacent surfaces shaped to bend a metal strip passing therebetween into tubular form with a gap between its longitudinal edges, thereby forming an incomplete tube, the inner member of the shaping die having a bore therein, a reciprocable rain workingin the bore and having a longitudinally extending passage, a feed device for discharging powder through the gap in the incomplete tube in front of the ram, means for closing the said gap to form a complete tube, the ram having a workingstroke which extends to a point adjacent the gap-closing means, a drawing-down die mounted in front of the latter and means for drawing a metal strip through the shaping die and a wire through the passage in the ram and the completed tube together with the wire and powder insulant within the tube, through the drawing-down die to reduce the diameter of the tube and compress the powder.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 289,725 Tainter Dec. 4, 1883 1,233,807 Read July 17, 1917 2,088,446 Specht July 27, 1937 2,123,778 Heilmann July 12, 1938 2,389,705 Wetzel Nov. 27, 1945

Claims (2)

1. A METHOD OF MANUFACTURING A CONDUCTOR INSULATED WITH POWDER AND ENCLOSED IN A METAL TUBE, BY A CONTINUOUS PROCESS, COMPRISING CONTINUOUSLY ADVANCING IN THE DIRECTION OF ITS LENGTH A METAL STRIP, SUBJECTING THE SAID STRIP, AS IT ADVANCES, TO A TRANSVERSE BENDING TO EFFECT RELATIVE MOVEMENT OF APPROACH OF ITS LONGITUDINAL EDGES AND TO GIVE TO THE STRIP A TUBULAR SHAPE WITH A GAP BETWEEN ITS LONGITUDINAL EDGES, CONTINUOUSLY ADVANCING A CONDUCTOR IN THE DIRECTION OF ITS LENGTH INTO THE TUBULAR SHAPED PART OF THE STRIP, SUPPLYING INSULATING MATERIAL IN THE FORM OF POWDER THROUGH THE GAP BETWEEN THE LONGITUDINAL EDGES OF THE TUBULAR PART OF THE STRIP TO THE INTERIOR OF THAT PART, JOINING TOGETHER THE LONGITUDINAL EDGES OF THE TUBULAR PART AT A PLACE IN ADVANCE OF THAT AT WHICH THE SUPPLY OF INSULATING POWDER TAKES PLACE THEREBY FORMING A COMPLETE TUBE, PUSHING FORWARD THE POWDER IN THE TUBULAR PART TO A PLACE ADJACENT THAT AT WHICH THE LONGITUDINAL EDGES HAVE BEEN JOINED TOGETHER AND REDUCING THE DIAMETER OF THE COMPLETE TUBE, THEREBY COMPRESSING THE POWDER THEREIN.

2. AN APPARATUS FOR THE MANUFACTURE, AS A CONTINUOUS OPERATION, OF A POWDER-INSULATED CONDUCTOR ENCLOSED IN A METAL TUBE, COMPRISING A SHAPING DIE WHICH TRANSVERSELY BENDS A METAL STRIP PASSING THERETHROUGH TO FORM AN INCOMPLETE TUBE HAVING A GAP BETWEEN ITS LONGITUDINAL EDGES, A RECIPROCABLE RAM WORKING IN A BORE IN THE SHAPING DIE, A DEVICE FOR FEEDING A POWDER INSULANT THROUGH THE GAP IN THE INCOMPLETE TUBE TO THE INTERIOR OF THE LATTER IN FRONT OF THE RECIPROCABLE RAM, MEANS FOR CLOSING THE GAP IN THE INCOMPLETE TUBE TO FORM A COMPLETE TUBE, THE SAID GAP-CLOSING MEANS BEING MOUNTED IN ADVANCE OF THE POWDER-FEEDING DEVICE, A DRAWING-DOWN DIE MOUNTED IN ADVANCE OF THE GAP-CLOSING MEANS, AND MEANS FOR DRAWING THE COMPLETE TUBE TOGETHER WITH A WIRE AND POWDER INSULANT THEREIN THROUGH THE DRAWING-DOWN DIE, REDUCING THE DIAMETER OF THE TUBE AND COMPRESSING THE POWDER THEREIN.

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