US2031014A - Machine for making electrical cables - Google Patents

Description

ATTORNEYS I INVE m H. A. STAPLES MACHINE FOR MAKING ELECTRICAL CABLES Orlglnal Flled Aprll 23, 1952 Feb. 18, 1936.

Patented Feb. 18, 1936 PNT" FFlCE.

MACHINE roa MAKING memos!- CABLES Horace A. Staples, PlainfleliL N. J.,.assignor to Habirshaw Cable and Wire Corporation, New York, N. Y., a corporation oi New York Original application April 23, 1932, Serial No.

607,063. Divided and this application October '6, 1932, Serial No- 636394 3 Claims. (Cl. 207-9) vision was made for minimizing the possibility of 15 the introduction of undesired oxide into the sheath of a metal cable as the same is formed from successive metal charges in an extrusion press.

The present invention has for its object the 20 provision of an improved machine for making a metal sheathed cable wherein provision is made for introducing a special atmosphere such as a reducing or inert gas into the extrusion press below the ram as the ram is withdrawn, which special gas atmosphere prevents the formation of undesirable oxide upon the top surface of the preceding metal charge and which special gas atmosphere is also maintained in the metal press during the recharging of the press with a new 30 metal charge so that oxide formation'upon the surfaceof or in the new lead charge is also precluded.

A further object of the present invention resides in the provision of an improved machine for making electrical cables wherein provision is made for introducing an inert or reducing gas into the press chamber when the'ram is being withjrawn and for maintaining such gas atmosphere in the chamber during the recharging of the press.

A further object of the present invention resides in the provision ofan improved machine with provisions for lubricating a lead press prior to a charging operation whereby subsequent extrusion operations are facilitated.

A futher object of the present invention resides in the provision of an improved machine for making lead sheath cable wherein a reducing or inert gas atmosphere together with a quantity of a lubricating medium may be introduced into the lead press cylinder prior to the introduction of a new charge of lead therein, which atmosphere and lubricating medium cooperate to prevent the formation of undesired oxide upon 55 the lead in the cylinder and which lubricating medium also serves to lubricate the walls of the cylinder to facilitate the subsequent extruding operation.

Further and other objects of the present incompanying specification and claims and shown in the drawing, which by way of illustration shows what I now consider to be a preferred embodiment of the invention.

The drawing shows in- Figure 1 the improved machine by which the present improved method of making a lead sheath cable is carried out; and 4 Fig. 2 shows a slightly modified construction Of ram.

The customary process of applying a lead sheath to a cable comprises the passing of the cable 10 through a closely fitting die H which almost abuts, another die I2 of a diameter slightly greater than that of the cable. Lead in a hot but solid form is pressed into the'space 'M between the two dies and thence into the cylindrical space I dbetween'the cable and the inside of the larger diameter die. The pressure for extruding the lead sheath is obtained by a hydraulic rain Id which presses upon a lead charge l! in the cylinder or lead press chamber l8.

Due to the large amount of lead which has to be used, particularly for a cable of even normal length, it is generally impracticable to perform the extruding operation continuously. It is necessary to stop and recharge the cylinder l8 from time to time and during these recharging operaperfect cables are produced.

In order to prevent the formation of the undesirable oxide, which subsequently becomes introduced into the lead sheath of the cable during the extruding operations, the previous procedure ismodified as will now be described.

The ram it is provided with a dummy head 22 carried on a stud 23 slidably fitting'the head of the ram it. The stud 23 is interiorly hollowed out as indicated at, 2t and from this hollowed out passage in the stud ports or passages 25 extend laterally as shown. The interior of the ram is also provided with a hollowed portion or conduit 28. Connected to the upper portion of the ram and in communication with the conduit portion 25 is a flexible connection 21 which eirtends to a three-way valve generally designated 28. Beyond the three-way valve 28 is an atomizing device 29 for atomizing a lubricating medium 5 such as oil which is taken into the atomizing device 29 from a reservoir-.30. 3! is a pipe or conduit throughwhich a reducing or other inert gas such as illuminating gas, carbon dioxide, steam or the like is supplied. under pressure. Such gas 613% surface is substantially at the bottom of the cylinder l8. With the rain in lower position, the three-way valve 28 is thrown to a position to admit a mist of lubricating oil and the reducing or other inert gas through the flexible. conduit 21 into the interior of the ram. The ram is then raised and the mist of oil and reducing gas is sprayed on the walls of the chamber or lead press cylinder as the ram is withdrawn upwardly. It will be understood that the dummy head 22 on the ram drops and allows the mist to flow laterally to the walls between the upper part of the ,dummy head and the lower part of the plunger arm. The gas and lubricating medium passes around the dummy head and down into the space between the top of the previous lead charge and the ram, as the ram is withdrawn upwardly. In this way a reducing atmosphere or inert gas atmosphere is maintained inthe chamber or space above the old lead charge between the upper surface thereof and the ram as the ram is being withdrawn. The lubricating medium sprays the bore of the lead press with oil, preventing sticking of the ram and facilitating the subsequent extruding operation.

The next step in the operation is to fill the chamber of the metal press cylinder or container with a new charge of metal such as lead. Such metal, for example molten lead, is introducedinto the chamber or container of the extrusion press through a removable pipe 32 which leads to a-lead pot or lead pump or other source of metal supply. The pipe 32 during the filling operation, is extended down into the special at mosphere in the container. After filling such pipe 32 is removed. During this filling operationthe three-way valve 28 is shifted to a position to shut off further supply .of gas and lubricating medium and to establish communication between conduit 21 and a pipe 33 so that upon subsequent lowering of the ram, gas can escape from the press chamber through the ram to the atmosphere. Pipe 33 may extend directly to atmosphere or it can extend into a water seal indicated by dotted lines at 34. The lead is then introducedinto the press chamber within press cylinder I8 and the reducing gas atmosphere is gradually displaced and discharged through pipe 33. During. the filling operation it will be appreciated that the reducing gas or other inert atmosphere within the chamber l8 prevents oxidation of the lead either in the new lead charge, which is introduced in a molten state, or upon the top surface of the old lead charge I I.

The machine is then ready for the subsequent extruding operation. During the extruding operation the three-way valve is shifted to closed position and extrusion proceeds in the usual manner.

By the above procedure oxygen is prevented from reaching the surface of the old lead charge or the molten lead while such lead is being introduced into chamber l8. The reducing gas or inert gas which was introduced in the chamber or cylinder of the lead press upon upward withdrawal of the ram prevents oxygen from the air from entering the chamber and precludes oxide formation.

Furthermore the lubricating medium supplements the reducing or inert gas upon being highly heated since such lubricating medium under heat itself becomes converted into hydro-carbon gas which has reducing characteristics.

Figure 2 shows a modified form of ram. With this form the supplemental or dummy head 22 is dispensed with and in lieu thereof the ram lea is so shaped that its lower integral portion constitutes the head. An interior conduit 26a is provided as before and openings or passages 25a extend to the periphery of the ram. Preferably a closing plug 40 is provided in the lower face of the ram I6a. With this construction the gas which is supplied under pressure to conduit 26a escapes into the space below the ram upon withdrawal of the ram by passing from passages Na around the edges of the lower end of the ram. The diameter of the lower end of the ram permits such gas flow. With the construction shown in Fig. 1 the diameter of the supplemental or dummy head is such as to provide for such gas flow upon upward withdrawal of the ram.

The present application constitutes a division of my copending application Serial No. 607,063, filed April 23, 1932, for Methods and machines for making lead sheathed cable." The method herein set forth is claimed in the aforesaid parent application, Serial No. 607,063.

What I claim is:

l. A machine for making a metal sheathed cable and comprising in combination, a chamber for receiving heated metal and from which the sheath is adapted to be extruded, a ram cooperable with said chamber for exerting pressure on metal therein, the said ram having an interior passage, a source of gas, and means for conducting a special gas atmosphere from said source and through said passage into said chamber during the withdrawal of said ramwhereby air is excluded from said chamber during extruding operations.

v 2. An extrusion press comprising in combination, a cylinder adapted to receive heated metal and provided with outlet means for forming a tubular sheath, a ram cooperable with said cylinder for forcing metal therefrom through said outlet means, the said ram having an interior passage communicating with outlets at that portion of the ram which enters the cylinder first, means comprising an extension head movably mounted on said ram for closing said last mentioned outlets when the ram is moving into the cylinder and through said passage into said chamber during the withdrawal of said ram whereby air is excluded from said chamber during extruding operations, and means for supplying lubricant to said special gas atmosphere and thereby causing the latter to carry the lubricant into said chamber. HORACEA. STAPLES.

for opening-said last mentioned outlets when the

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