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Publication numberUS2887222 A
Publication typeGrant
Publication dateMay 19, 1959
Filing dateMar 23, 1956
Priority dateMar 23, 1956
Publication numberUS 2887222 A, US 2887222A, US-A-2887222, US2887222 A, US2887222A
InventorsAubrey Latin, James Conning, Wilson Grieve George Thomas
Original AssigneeOkonite Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Extrusion apparatus for sheathing electric cables
US 2887222 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

y 9 1959 A. LATIN ET AL 2,887,222

sxwausxou APPARATUS FOR snmmmc mzcmc CABLES Filed March 23, 19 56 2 Sheets-Sheet 1 a INVENTORS. AUBREY LATIN, GEORGE moms WILSON GRIEVE;

amt JAMES CONNING 4 ATTO RN E V.

y 1959 A. LATIN ,ET AL 7, EXTRUSION APPARATUS FOR SHEATHING ELECTRIC CABLES Filed March 23, 1956 2 Sheets-Sheet Q I m Q N w :2 Q m w "3 r I 3 a]: I 'II 3; v I

E: N 3 v INVENTORS. AUBREY LATIN, GEORGE THOMAS wusou emzv:

mmL JAMES cow m N6 A T'T'ORNEK United States Patent F EXTRUSION APPARATUS FOR SHEATHING ELECTRIC CABLES Aubrey Latin, Bayswater, London, George Thomas Wilson Grieve, Woolwich, London, and James Canning,

Bexley, England, assignors to The Okonite Company,

This invention relates to the sheathing of electric cables by extrusion, namely, by converting a mass of metal in a plastic state into an elongated body of the required crosssectional shape by forcing the plastic metal through an appropriately shaped orifice.

In producing sheaths by conventional equipment it has been found difficult to maintain the wall thickness of the sheath constant within very close limits at all points around the sheath circumference and at all points along its length. Accordingly, the practice has been to produce a sheath whose average wall thickness is considerably above that of the minimum permissible wall thickness. This practice is safe but is extravagant of material.

The present invention enables a cable sheath to be produced by extrusion and having a wall thickness which is constant within fine limits, thereby enabling economies in material to be effected.

. By the present invention we provide for extruding a metal cable sheath in the form of a metal tube, and then simultaneously operating upon the internal and external surfaces of each elemental length of the advancing tube, to displace metal, in a direction having a substantial circumferential component, from elemental areas of wall the thickness of which is materially greater than the desired thickness to elemental areas of wall of a thickness materially less than the desired thickness. In this way inequalities in the wall thickness of the elemental length are substantially reduced, and the wall of the sheath is caused to assume a thickness which is, within close limits, constant throughout the circumference.

When desired, the circumferential displacement of the metal may be followed by a reducing process, to reduce the sheath to the size required for the finished sheath.

In general, our improved apparatus comprises metal extrusion apparatus having a circular inner die and a circular outer die, which cooperate to form an annular extrusion orifice for the formation of a metal tube. The inner die projects beyond the outer die to provide an internal gauging member, and cooperating with this internal gauging member is an external gauge, comprising a plurality of shoes carried by a rotatable disc mounted in the front end of the extrusion press. As the disc is rotated, the shoes will displace metal from elemental areas of wall of which the thickness is materially greater than the desired thickness to elemental areas of sheath wall of a thickness materially less than the desired thickness.

In the accompanying drawings,

Fig. 1 is an end elevational view of an embodiment of our invention; and

Fig. 2 is a section on the line 2-2 of Fig. 1.

Referring to the drawings in detail, the die box 2 comprises upper and lower parts 4 and 6, making joint in a horizontal plane. The contiguous faces of these parts are recessed, and the recesses cooperate to form an axial or through-bore 3. Within this bore, toward the rear or left-hand end of the bore as viewed in Fig. 2, is positioned a tubular mandrel or point holder 8, held in place by a tubular nut or tubular, externally threaded plug 10. 1

At the front end of the mandrel 8, viz., the right-hand end as viewed in Fig. 2, the through-bore is enlarged to form between the mandrel and the wall of the throughbore 3 an annular forming chamber 12, into which a passage 14 leads from an opening 16 in the upper face of the die box.

Threaded into the inner end of the mandrel 8 is a tubular inner die 18. Thisdie 18 is externally conical. C0- operating with the inner die 18 is a tubular outer die 20, pressed into the front end of the through-bore 3. Set into the die box parts 4 and 6 immediately behind the outer die 20 is a masking ring 22, the rear or inner face of this ring being conical. The two die members and the masking ring 22 form an annular extrusion orifice, the area 21 of which between the masking ring 22 and the inner die 18 has a converging cross-section.

The inner die 18 extends forwardly or outwardly of the die box beyond the outer die 20, as ShOWIll at 24. The surface of this extension is conical, and the extension constitutes an internal gauging member.

Rotatably mounted at the front end of die box 2 in bearings 25 in the front face of the outer die or matrix 20 is a centrally apertured, shoe-carrying disc 26, having a toothed rim and driven by a pinion 28.

In the front face of the disc 26 are three radially,

extending grooves 30, spaced. apart, each groove receiving a radially extending shank 32 of a shoe or external gauging member 34, these shoes overlying and cooperating with the conical surface of the internal gauging member 24, as illustrated in Fig. 2. l

The shoe shanks 32 are held slidably in the grooves 30 by a cover plate 36, which is clamped to the disc 26 by stud bolts 38, which pass through circumferentially extending slots 40 in the cover plate, so that the cover plate is capable of being angularly adjusted relative to the disc to an extent determined by the length of the slots.

Each shoe shank 32 carries a stud 42, which projects through an arcuate slot 44 in the cover plate. These slots 44 do not extend circumferentially with respect to the disc 26 and its cover plate 36 but lie at a small angle to the circumferential, so that, as the cover plate is rotated relatively to the disc, the radial positions of the three shoes are adjusted simultaneously and, to the same extent, in inward or outward directions, depending upon the direction of rotation of the cover plate relative to the disc.

It will be apparent from all of the foregoing that, as a sheath, such as 46, is being extruded upon a cable body 48, we operate upon the internal and external surfaces of the same simultaneously through the medium of the internal gauging member and the external gauging mem-- bers provided by the shoes 34, to displace metal, in a direction having a substantial circumferential component, from elemental areas of sheath wall of which the thickness is materially greater than the desired thickness to elemental areas of sheath wall the thickness of which is materially less than the desired thickness.

This application is a continuation-in-part of our copending application Serial No. 289,618, filed May 23, 1952, now Patent No. 2,751,077, dated June 19, 1956.

What we claim is:

l. Extrusion apparatus for sheathing electric cables, said apparatus comprising, in combination, a metal extrusion die box provided with an axial through-bore; a tubular mandrel mounted in said through-bore; a tubular nut threaded in the rear end of said bore for holding said mandrel in place; an inner tubular die threaded into the inner end of said mandrel; an outer tubular die member pressed into the forward end of said through-bore, where-t Patented May 19, 1959 asaagaaa by the two die members provide an annular extrusion orifice concentric-with said through-bore for the formation of a sheath about a cable core passing through the throughbore, the said inner die projecting forwardly beyond said outerdie member, the projecting portion of the inner die having a conical exterior and constituting an inner gauge; a: disc at the front end of the die box provided with a central aperture coaxial with the die box through-bore; a plurality of radial slots in the outer face of said disc; a plurality of work engaging shoes, each provided with a radially extending shank which lies in the said disc slots; a cover plate for said disc having a central aperture coaxial with said disc-aperture, said plate overlying the shoe shanks and being bolted to the disc; a stud carried by each shoe shank, said cover plate being provided with slots each of'which receives a shank stud, said shoes providing outer gauging means cooperating with the inner gauge, and'the shank studs and their receiving slots holding the shoes against radial movement in their shank-receiving slots; and means for rotating said disc, shoes, and cover plate as a unit about the axis of the die box through-bore.

2. Extrusion apparatus for sheathing electric cables, said apparatus comprising, in combination, a metal extrusion die box provided with an axial through-bore; a tubular mandrel mounted in said through-bore; a tubular nut threaded in the rear end of said bore for holding said mandrel in place; an inner tubular die threaded into the inner end of said mandrel; an outer tubular die member pressed into the forward end of said through-bore, whereby the two die members provide an annular extrusion orifice concentric with said through-bore for the formation of a sheath about a cable core passing through the throughbore, the said innerdie projecting forwardly beyond said outer die member, the projecting portion of the inner die having a conical exterior and constituting an inner gauge; a disc at the front end of the die box provided with a central aperture coaxial with the die box through-bore; a plurality of radial slots in the outer face of said disc; a plurality of work-engaging shoes, each provided with a radially extending shank which lies in the said disc slots; a cover plate for said disc overlying the shoe shanks and having a central aperture coaxial with said disc aperture; a plurality of arcuate slots through said cover plate, said slots being concentric with the said cover plate aperture; bolts extending through said slots for bolting the cover plate and disc to each other, said cover-plate slots being elongated whereby, upon loosening of said bolts, the cover plate may be. adjusted angularly relatively to said disc; a stud carried by each shoe shank; elongated arcuate slots through said cover plate, each slot receiving a shank stud, and said slots extending at an angle to the circumference of said disc and cover plate whereby, upon angular adjustment of the cover plate, the said shoes will be shifted radially of the disc and cover plate; and means for rotating the disc, shoes, and cover plate as a unit about the.

axis of the die box through-bore.

References Cited in the file of this patent UNITED STATES PATENTS 327,835 Tatham Oct. 6, 1885 2,142,526 Norris Jan. 3, 1939" 2,233,106 McGuire Feb. 25, 1941 2,234,340 Gillies Mar. 11', 1941 2,262,716 Wolfer Nov. 11, 1941 2,359,453 Waldron Oct. 3, 1944 FOREIGN PATENTS 12,139 Great Britain Mar. 4, 1915 681,217 France -Jan. 28, 1930 410,624 Great Britain May 24, 1934' 544,386 Great Britain Apr. 10, 1942

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US327835 *Feb 9, 1885Oct 6, 1885 Attachment for lead-pipe presses
US2142526 *Jun 21, 1938Jan 3, 1939Gleave Norris RichardExtrusion machine
US2233106 *Aug 30, 1937Feb 25, 1941Western Electric CoCable sheathing machine
US2234340 *Dec 7, 1939Mar 11, 1941Western Electric CoMethod of and apparatus for forming metal
US2262716 *Nov 30, 1937Nov 11, 1941Gen Cable CorpMethod and apparatus for producing cable sheaths
US2359453 *Jun 24, 1941Oct 3, 1944Barnes Waldron FredericManufacture of solid-drawn iron and steel tubes
FR681217A * Title not available
GB410624A * Title not available
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US6769161 *Sep 22, 1999Aug 3, 2004Scimed Life Systems, Inc.Radial stent crimper
US6823576 *Oct 1, 2001Nov 30, 2004Scimed Life Systems, Inc.Method and apparatus for contracting, loading or crimping self-expanding and balloon expandable stent devices
US6915560 *May 23, 2003Jul 12, 2005Boston Scientific Scimed, Inc.Apparatus for contracting, loading or crimping self-expanding and balloon expandable stent devices
US6968607Jul 21, 2003Nov 29, 2005Tom MotsenbockerStent crimping method
US6988881Mar 26, 2002Jan 24, 2006Machine Solutions, Inc.Balloon folding technology
US7021114Apr 16, 2004Apr 4, 2006Boston Scientific Scimed, Inc.Stent crimper
US7143625Apr 16, 2004Dec 5, 2006Boston Scientific Scimed, Inc.Stent crimper
US7407377Jul 13, 2005Aug 5, 2008Machine Solutions, Inc.Balloon folding technology
US7587801 *Jun 23, 2005Sep 15, 2009Boston Scientific Scimed, Inc.Stent crimper
US7992273Aug 9, 2011Boston Scientific Scimed, Inc.Crimping apparatus for reducing size of a stent
US8128860Jul 13, 2005Mar 6, 2012Machine Solutions, Inc.Balloon folding technology
US8533925Jul 11, 2011Sep 17, 2013Boston Scientific Scimed, Inc.Method for contracting or crimping stents
US8679398Mar 1, 2012Mar 25, 2014Machine Solutions, Inc.Balloon folding technology
US20020163104 *Mar 26, 2002Nov 7, 2002Tom MotsenbockerBalloon folding technology
US20040093720 *Jul 21, 2003May 20, 2004Tom MotsenbockerStent crimping method
US20050229670 *Apr 16, 2004Oct 20, 2005Scimed Life Systems, Inc.Stent crimper
US20050234537 *Apr 16, 2004Oct 20, 2005Scimed Life Systems, Inc.Stent crimper
US20050244533 *Jul 13, 2005Nov 3, 2005Tom MotsenbockerBalloon folding technology
US20050275140 *Jul 13, 2005Dec 15, 2005Tom MotsenbockerBalloon folding technology
US20050277877 *Aug 17, 2005Dec 15, 2005Tom MotsenbockerBalloon technology
US20100154195 *Aug 6, 2009Jun 24, 2010Boston Scientific Scimed, Inc.Method and apparatus for contracting, or crimping stents
Classifications
U.S. Classification72/68, 72/268, 72/256, 72/121
International ClassificationB21C25/06, B21C25/00
Cooperative ClassificationB21C25/06
European ClassificationB21C25/06