US2085977A

US2085977A - Apparatus for the continuous extrusion of metals

Info

Publication number: US2085977A
Application number: US93260A
Authority: US
Inventors: Hill Harry; Beckinsale Sydney; Wood Abbey; Slater Walter French
Original assignee: HENLEY EXTRUSION MACHINE COMPA
Current assignee: HENLEY EXTRUSION MACHINE COMPA; HENLEY EXTRUSION MACHINE COMPANY Ltd
Priority date: 1935-08-07
Filing date: 1936-07-29
Publication date: 1937-07-06
Anticipated expiration: 1954-07-06

Description

July 6, 1 937. H HILL ET 2,085,977

APPARATUS FOR THE CONTINUOUS EXTRUSION OF METALS Filed July 29, 1936 '5 A v A 21 L 20 24 1k 4 23 l 2 I4 23 Patented July 6, 1937 i'i'E star APPARATUS FQR THE CGNTINUOUS EX- -TRUSION OF METALS a British company Application July 29, 1936, Serial No. 93,260 in Great Britain August 7, 1935 4 Claims.

This invention deals with the extrusion of metal by a method dependent upon the relative rotation of two concentric members (usually cyllndrical) into the space between which metal is fed and is there moved forward in the plastic state by a. screwing action. The metal is usually fed in at one end of the two members while it is in the molten state and is then cooled so as to become plastic, s forced forward into an extrusion chamber at the other end and there passes through a die or between a pair of dies. the two concentric members is provided with a series of helical projections forming or equivalent to a screw thread and the other is also provided with projections which may run parallel with the axis or may have some other form, being, for instance, screw threads of the opposite hand to those on the first mentioned member.

The present invention applies to the type of machine in which the outer concentric member is stationary and the inner rotates. In this type of apparatus, it is usual to apply the drive to the rotary member at the rear end. In accordance with the present invention, the drive is applied at the front end. This may be the sole drive for the rotary member or may be combined with a second drive applied at the rear end.

By applying the drive to the front end, the result is obtained that the driving torque acts directly upon the rotary member at the place where the resistance to rotation is greatest. Owing to the fact that the metal near the delivery end is at a lower temperature than that nearer the rear end and is also at the maximum pressure, the metal near the delivery end exerts the maximum frictional resistance and the maximum resistance to deformation or shearing.

The drive is applied at the front end by forming a lateral extension on the driving member (that is, the inner member) or by attaching a driving part to the member. In either case, passages will be provided through the lateral extension or through the attached part for the passage of the metal from the driving member to the extrusion chamber and the outlet at the die.

The invention will be further described by the aid of the accompanying drawing, which illustrates by way of example a form of construction of a machine in which the invention is embodied. Figure 1 is a longitudinal section of the upper part of the front end (delivery end) of the ma.- chine. Figure 2 is an end view of the rotary member of the machine looking from the plane A-A marked on Figure 1 in the direction of the arrows. Figure 3 is a developed section through One of a part of the rotary member taken on the line B-B of Figure'2. In the parts with which the present invention is concerned the machine is symmetrical about the centre line ill-4E9 Figure 1, so that it is unnecessary to show the lower half of the figure. The two concentric members are the outer part H, which also forms the casing of the machine, and the inner part it which at the front end has the laterally outward extending disc 53 formed integrally with it. The adjacent surfaces of these two parts are cylindrical and work with slight clearance between them. In the cylindrical wall of the casing l i is out a helical thread M which extends from the rear end, not

shown, to the front end in the neighbourhood of the disc 53. In the cylindrical face of the inner part i2 are cut a, number of longitudinal grooves iii.

At the rear end of the machine, not shown, the space between the two concentric parts H and i2 is in connection with a.- feeding chamber which is kept full of molten metal, such as lead or lead alloy, so that the threads in the casing l l and the longitudinal grooves in the inner part l2 are maintained full of metal. By the applica- 1 tion of appropriate cooling means the metal within these spaces is rendered plastic, that is to say, it approaches near to the solid state. The relative motion between the parts i2 and i I and the configuration of the adjacent surfaces of these parts causes the metal to be fed forward towards the delivery end by a screwing action. In this way it reaches the extrusion chamber l6 and passes out between the dies H and i8. In the arrangement illustrated, the dies are circular so as to produce a thin solid tube. This may, for instance, be the sheath of an electric cable, the core of which passes through the tube I9 so as to be drawn forward by the sheath extruded on to it between the dies. The tube I9 is fixed, being anchored by the rear part of the machine' The disc I3 is provided on its periphery with a ring of teeth 20 through which it is driven by a suitable pinion or worm. This disc, except at the part where the drive is applied, is enclosed between two fixed side walls 2| and 22, which are bolted together near their outer periphery. The wall 2| is a continuation of the casing I I. The wall 22 forms the end plate of the machine and supports the outer die I8. The disc I3 is supported in position by ball-thrust bearings 23 and by journal bearings 24. As-previously indicated, the part i 2 is also supported on the fixed cylinder l9. The adjacent surfaces of the parts l2 and I9 are preferably lubricated by oil under pressure TENT OFFICE and a similar system of lubrication may also be employed for the journal bearings 24.

To prevent the plastic metal from being forced out between the disc I3 and the side walls 2i and 22, appropriate packing means are provided. These are shown as rings 25 which are housed in recesses in the adjacent faces of the disc l3 and side walls 2| and 22. These packing rings comprise an inner split ring of steel carrying a facing of softer metal, for instance copper, which works against faces on the two members (driving disc and stationary wall) and bridges the gap between them. These rings are pressed outward by the plastic metal behind them. The soft metal facing is deformed by pressure and rubbing so that it takes up a shape which fits the faces on the driving disc and side wall. A similar packing arrangement 26 is employed to prevent the entry of plastic metal between the parts l2 and H3.

The ports 21 for the passage of the plastic metal through the disc 13 to the extrusion chamber 16 can be shaped so as to cause a reduction of the pressure exerted by the plastic metal on the delivery side of the disc. This shaping can be carried out by taking account of the flowing motion and the high viscosity of the metal so that the streams passing through and issuing from the ports will either flow clear of the surface of the disc or exert a comparatively low backward pressure thereon, thatis, a pressure materially less than would be the case if the forward motion of the metal were not taking place. This shaping is illustrated in Figures 2 and 3. In these figures the numerals I and 8 have been used to indicate points on the walls of the ports. The arrow 28 indicates the direction of rotation of the disc. The arrow 29 indicates the general direction of movement of the plastic metal in passing from one side of the disc is to the other. It will be seen that the stream of metal passing through the central port shown in Figure 3, will press more strongly against the surface 3-5 than against the surface 68. This effect will tend to produce a resultant pressure in the direction of the arrow 29 which will in part balance the pressure in the opposite direction which is exerted by the metal in the extrusion chamber IS on the end surface of the rotating cylinder l2.

What we claim as our invention is:-

1. Apparatus for the continuous extrusion of metal by a screwing action, comprising two concentric members, receiving the metal between them and operating thereon by their adjacent surfaces, the outer member being stationary and the inner rotatable, an extrusion chamber at the delivery end of the machine, said chamber having a shaped outlet for the metal and means for applying the drive for rotating the inner member at the front (that is, the delivery) end thereof.

2. Apparatus for the continuous extrusion of metal by a screwing action, comprising two concentric members, receiving the metal between them and operating thereon by their adjacent surfaces, the outer member being stationary and the inner rotatable, an extrusion chamber at the delivery end of the machine, said chamber having a shaped outlet for the metal, a laterally outward extending part on the inner member near the front end thereof, said part having a passage through it for the feeding of metal to the extrusion chamber, and rotary driving means operating upon said part.

3. Apparatus for the continuous extrusion of metal by a screwing action, comprising two concentric members, receiving the metal between them and operating thereon by their adjacent surfaces, the outer member being stationary and the inner rotatable, an extrusion chamber at the delivery end of the machine, said chamber having a shaped outlet for the metal, a disc on the inner member near the front end thereof and extending outward therefrom, stationary side walls enclosing said disc and connected with the outer concentric member, packing means between said disc and side walls and driving means acting on the periphery of said disc.

4. Apparatus for the continuous extrusion of metal by a screwing action, comprising two concentric members, receiving the metal between them and operating thereon by their adjacent surfaces, the outer member being stationary and the inner rotatable, an extrusion chamber at the delivery end of the machine, said chamber having a shaped outlet for the metal, a laterally outward extending part on the inner member near the front end thereof, said part having a passage through it for the feeding of metal to the extrusion chamber, and rotary driving means operating upon said part, the walls of the passage through the said part being shaped and disposed to reduce the end thrust exerted by the metal on the rotatable member when it is rotating.

HARRY HILL. SYDNEY BECIQINSALE. WALTER FRENCH SLATER.