US2171062A - Press for the extrusion of lead and other metals - Google Patents

Description

A l l g. '29, 1939. G. 'r w. GRIEVE 2,171,062

PRESS FOR THE EXTRUSION OF LEAD AND OTHER METALS Filed Sept. 28, 1937 a Sheets-Sheet 1 67 //v v/s/v Toe 5 6506265 Tuonns hl/Lson' Gem-v:

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Arman/5K5 Aug. 29, 1939. G. T. w. GRIEVE 2,171,062

PRESS FOR THE EXTRUSION OF LEAD AND OTHER METALS Filed Sept. '28, 1937 s Sheets-Sheet 2 Fig.2. Q 85 2 74 //V Vf/V T02 050K615 TIwrmS Wusau GRIEYE Aug. 29; 1939. G. T. w. GRIEVE 2,171,062

PRESS FOR was EXTRUSION OF'LEAD AND 0mm urmns 1 3 Sheets-Sheet 5 Filed Sept. 28, 1937 Fig. 5.

IN l/E/V Toe GEORGE moms WILSON GRID? mmfmb orrazwsy;

Patented Aug. 29, 1939 PRESS FOR THE EXTRUSION or LEAD AND o'rnna METALS George Thomas Wilson Grieve, London, England,

assignor to Callenders Cable and Construction Company Limited,

British company London, England, 8.

Application September 28, 1937, Serial No. 168,060 1 Great Britain October 30, 1936 25 Claims.

The invention relates to pressesof the reciprocating ram type for extruding lead and other metals, which are fed into the container while molten and cooled in the container and are ex-" 5 truded in the plastic state.

The usual method of operating such presses is to withdraw the ram from the container, to pour in molten metal so as to fill the container, then to apply light pressure by a short forward movement of the ram into the container and at the same time to apply cooling means, or allow the -metal to cool until it is sufliciently solidified. to permit the ram to be forced forward. At this stage the extrusion commences and proceeds until the ram has completed its working stroke; at this point it is withdrawn and the cycle of operations repeated. It will be seen that in this procedure the extrusion takes place by a series of stages alternating with periods offrest during which the container is being filled and the metal cooled. It will also be seen that the opening of the container for the pouring in of the metal permits the entry of gas and exposes the surface of the metal remaining in the container and also exposes the surface of the ram. This gives the possibility of the fouling of these surfaces and the introduction or production within the 'container of .oxide or other impurity. It is possible to arrange that the container is not open to the of molten metal for the ram and by this means the possibility of contamination of the contents of the press may be greatly reduced. Even in such cases, however, the extrusion proceeds in stages with comparatively long periods of'rest for the-refilling of the container.;

In accordance with the present invention.

. surrounding atmosphere when the ram is drawn back for filling. This is done by providing a seal the press comprises a main ram adapted to exert a 40 steady pressure upon the metalto be 'extruded, and an auxiliary ram which is adapted to serve as a pump to' deliver metal in'a molten condition to a container, and the two rams and the container are coaxially disposed. In one form of construction themain and auxiliary rams and the container are concentrically disposed, the main ram entering'one end of the container and the auxiliary ramworking within the main'ram to .draw molten metal into the main ram and deliver 60 it to one end of the container, the etal being extruded from the other end thereof. In another form of construction, the container has a closure memberat one end provided with a bore in which operatesthe auxiliary ram and the other end of construction the main ram forms, in effect, a part of the container and it has an putlet at its opposite end for the metal to be extruded. In another construction a fixed main ram enters one. end of a movable container, the metal being ex- 5 truded from the opposite end of the latter, and 'the auxiliary ram operates within the fixed main ram. It will be understood, therefore, that in some constructions the metal will be extruded from the container and in others, from the main 10 ram and that, in consequence, where appropriate, the term container must 'be regarded as including the main ram.

The metal in the container is always under the extrusion pressure exerted by the main ram. 15 This will generally be actuated hydraulically. The actual extrusion work is performed by the auxiliary ram in its pumping stroke. In this stroke the molten metal is delivered to the container more rapidly than the plastic metal'is be- 20 ing extruded from the container. The main ram provides for the expansion 'of the container volume to-receive the pump charge and for the exertion-of a steady pressure upon the metal in the container. By its outward movement it 25 stores up some of the energy applied by the pump and this energy is used during the interval be tween two deliveries from the pump into the container.

During an extrusion operation the container 30 contains both molten metal and metal in a plastic condition. The metal is pumped into the 'con tainer in. a molten condition, is cooled down to bring it to the plastic state and is extruded in that state. By arranging the main and auxiliary -3-. rams and the container coaxially we provide that the molten metal is delivered by the auxiliary ram into the container at 'ornear to one end thereof while the plastic metal is extruded from the other end of the container. For continuous 40 extrusion it is necessary to ensure that there is always a body of plastic metal ready to be extruded. By delivering the molten metal to the end of the container remote from the outlet it can lie-ensured that a body of plastic metal is maintained in the container ready to be extruded therefrom." The delivery of molten metal to one 'end of the container also facilitates the control of the temperatures of the container and of the metal therein at different-parts thereof so as to ensure that as the molten metal is forced through the container it is changed from the molten to the plastic condition.

The coaxial disposition vof the two rams and container'also has the advantage of permitting the molten metal to be delivered symmetrically with regard to the container, thus providing for a symmetrical flow of heat from the center line of the container radially outwards. This provides for the maintenance of a substantially constant temperature at any one point in the container 'and assists in facilitating the required control of for a satisfactory union of the metal being delivered by the auxiliary ram with the metal already within the container. It also ensures a free entry of the molten metal being delivered and of a free action of the delivery valve which closes the feed'passage when the auxiliary ram is not delivering.

By arranging for the auxiliary ram to deliver a small volume of metal at each pum'pingstroke, it is provided that the movement of the main ram is also small, thus permitting the temperature conditions within the container to be maintained substantially constant. It also enables a relatively small body of molten metal to be localized at one end of the container which facilitates the control of the temperature of the metal in the container and the obtaining of an extruded product of the required dimensions. It also reduces the tendency for the molten metal to escape past the main ram out of the container.

A steep temperature gradient will be provided at different parts thereof, forinstance, by applying heat near the point of entry of the molten metal and taking away heat at a short distance therefrom. In some cases the supplying of heat may be performed entirely bythe entry of molten metal, which is sent in at a temperature sufficiently above the melting point'to maintain the localized body of molten metal within the container between the delivery strokes.

Some forms of construction of apparatus in accordance with the. invention are illustrated as ex-' amples in the accompanying drawings, wherein Figure 1 shows a sectional elevation of one form of apparatus. Figure 2, a sectional elevation of a modified form of construction, and

Figure '3, a similar view of another modified form of construction. I

The various forms of press shownin the accompanying drawings are suitable for the extrusion of lead sheaths around electric cables.

' Referring to Figure 1 of the drawings, the press shown therein, comprises a container 2 for metal, a main ram I5 for exerting a steady pressure upon the metal, and an auxiliary ram I3 provided with a head It, adapted to act as a pump to deliver molten metal from-a feeding vessel 9 to the upper portion'of the container. Metal in a plastic condition is extruded from the lower end of the container 2 through an orifice 4 in a die box 5 carried by the container, the cable around which the metal is extruded in the form of a sheath, being drawn through the die box 4 in a horizontal direction.

The lower portion of the main ram l5 enters the upper portion of. the container 2 and, as will be seen from the figure, the main and auxiliary rams are arranged concentrically, the'auxiliary ram working within the bore of the main ram which latter has the form of a hollow cylindrical.

member provided with an orifice 1| at its lower end. The molten metal is forced through the bore of the main ram l5 and through the orifice H past a ball l which may be made of steel and which serves as a non-return valve. .The ball allows metal to be forced into the container 2 but prevents metal being forced from the container into the bore of the main ram I5. The ball is loosely carried in a cage"! ll fixed to the lower end of the main ram. In the figure the ball 10 is shown in the position in which it closes the orifice H.

Molten metal is supplied to the feeding vessel 9 by way of a pipe 56 which is joined at one end to a melting pot (not shown) and at its other end to thefeeding vessel 9, the pipe 56 having an inlet into the feeding vessel. The metal is drawn into the bore of the main ram 95 by the auxiliary ram l3 from the feeding vessel 9 through passages 58 and 59 the passage 59 being formed in the wall of the main ra'm i5 and the passage 58 in the wall'of the lower portion of a connecting member it having the form of a sleeve- Any metal leaking past the head M during the downward stroke of the auxiliary ram l3 finds its way back into the feeding vessel 9 through passages 60 and 6| formed in the walls of the main ram liand connecting member 16 respectively. The lower end of the connecting member i6 enters the upperend of the feeding vessel 9 which is maintained filled with molten metal.

- The auxiliary ram l3 has the form of a cylindrical rod and is screwed at its upperend into the lower end of a hydraulic ram 3 and the latter works in the bore of a hydraulic plunger I. The plunger works in a hydraulic cylinder 6 'and is joined to the main ram i5 by the connecting member 16 which is a hollow member flanged at its upper end and secured at that end to the lower .end of the plunger l by bolts Ill. The connecting member l6 surrounds the upper portion of the main ram 15 and is fixed to it and th internal dimensions and shape of the upper portion of the connectingmember are such as to form a continuation of thebore of the plunger l and to provide for a reciprocating movement of the auxiliary ram l3 and hydraulic ram 3. Y

The feeding vessel 9'is screwed at its upper end to the lower end of' an extension 8" of the hydraulic cylinder 6, the extension 8 being secured to the lower end of the hydraulic cylinder by bolts 1.

The upper end of the hydraulic cylinder 6 has a plate l8 secured to it by bolts l9 and water tight joints are provided forbetween the upper portion .of the plunger I and the plate I8 by a gland, and between the upper portion of the plunger I and the hydraulic cylinder 6, by packing rings 2| and 22 and glands 23, 24 and 2.5. Between the lower portions of the hydraulic ram '3 and of the plunger l are provided packing rings 26 to provide water tight joints at those parts, and to avoid entry of air to the molten metal in the feeding vessel 9 there are provided at the upper end of the feeding vessel, a gland 21 se- 5 cured to the feeding vessel by bolts 28, and a packing ring 29.

A'steady pressure is maintained upon metal in the container 2 during an extrusion operation by pressure water which entersan annular space 38 provided for by giving two different diameters to the plunger I. The water enters the space 38 through a pipe-3l and bears upon an annular urface 32. The water also exerts pressure upon?the upper end 33 of the hydraulic ram 3 and upon an annular surface 34 provided by reducing the diameter of the hydraulic ram 3 for an appropriate length to forman annular passagev35. Water entering the pipe 3| passes into the annular' space 38 through a passage 36 to exert pressure upon the annular surface 32, and passes from the annular space 30 into a passage 31 with which communicate a passage 38 and the annular passage 35. The passage 38 communicates with a; pipe 39 and the latter through a valve 42 5 with a pipe 48 which atone end is screwed into the valve andat its other end into a plug 43 which is screwed into the upper end of the plunger I. The plug 43 has a passage M which terminates in a space 44 provided between the lower a side of the plug and the upper end 33 of the hydraulic ram 3.

Pressure water entering the pipe 3| thus exerts a steady pressure upon the plunger I and upon the main ram I5 and the water also exerts'pressure on the upper end 33 and upon the annular surface 34 of the hydraulic ram 3. Since the hydraulic ram 3 and auxiliary ram I3 are joined together, pressure exerted by the water on the hydraulic ram is communicated to the auxiliary ram. The pressure exerted upon the auxiliary ram 13 causes it to reciprocate within the main ram I5, the pressure exerted upon the annular surface 34 moving the auxiliary ram upwards to draw molten metal from the feeding vessel 9 into i the bore of the main ram I5. The pressure exerted upon the upper end 33 of the hydraulic ram 3 causes downward movement of the auxiliary ram I3. and the'expulsion of molten metal from the'main ram I5 past the ball I8 into the upper portion of the container 2.

When the auxiliary ram I3 is moving upwards to draw molten metal from the feeding vessel 9, the space 44 is cutoff from, communication with the pipe 39 so that pressure is not then ex erted upon the end of the hydraulic ram 3. 'The space 44; however, is then, placed in communication with a waste pipe 45 which allows water to be discharged freely from above the hydraulic 'ram 3.. This cutting off of the pressure water and the flow of water to waste is efl ected by the valve 42 which is operated by an electric motor .46. Although during its downward stroke. the hydraulicramdhas pressure exerted upon it simultaneously at its upper end 33 and upon the annular surface34, this will not present any difliculty as the area of the end 33 is considerably greater than that of the annular surface 34 so that the total pressure exerted upon the end 33 will be correspondingly greater than that exerted upon the annular surface 34.

The valve 42 comprises a cylinder 41 to which,

the pipes 39, 48 and 45 are fixed, and a piston rod 48 provided with pistons 49 and 58. When the piston 58 places the pipes 39 and 48 out of communication with each other, the piston 49 is in the position in which the pipe 48 is in communication with the waste pipe 45. a In the position shown in the figure, the piston 58 allows communication between the pipes 39 and 48 so that pressure is now being exerted upon the upper end of the hydraulic ram which is ready to commence its downward stroke to cause the auxiliary ram I3 to expel molten metal from the main ram I5 into the upper end of the container 2. The other piston 49 places the pipe 48 out of communication with the waste pipe 45. The piston rod 48 is acted upon by a cam 5| of an appropriate shape to reciprocate the rod and pistons in the cylinder 41 against the action of a spring 55. The cam is mounted on the shaft 52 of the motor 46 and the motor. is mounted on an extension 53 of a bracket 54. The latter supports the valve 42 and is carried by the plunger.

The molten metal is forced by the auxiliary ram I3 through the lower end of the main ram I5 past the ball I8 into the upper end of the container 2 and it is necessary, therefore, to ensure that the metal in these parts is always maintained in a molten state to provide for free entry of the. metal into the container 2. For this purpose the feeding vessel 9 and the upper portion of the container 2 are surrounded by a furnace 62 containing burners 63 disposed adjacent to the place of entry of the metal from the main ram I5 into the container 2. To ensure that the metal in the pipe 56 is maintained in a molten state the Before the metal is extruded through the die 5 it requires to be cooled to a plastic condition and for this purpose the lower portion of the container 2 is surrounded by a water jacket 66 provided with an inlet pipe 61 at its lower end. The other pipes 68 provide an outlet for the water from the jacket 66 and may be used to control the amount of cooling required, the amount'of water in the jacket being indicated by the flow of water from a particular outlet pipe, the valves'69 being all open. .For example, if water is flowing from the uppermost of the pipes 68, this will indicate that the maximum'amount of cooling is taking place.

'An annular projecting portion I8 provides for close the orifice 'II at the lowerend of the sleeve- I5.' As the auxiliary ram I3 descends it. pumps molten metal from the main ram- I5 through orifice II into the container 2, pressing the ball I8 downwards, the steady pressure applied to the annular surface 32 of the plunger I causing extrusion of plastic metal through the diebox 5. Y

The molten'metal is pumped into the container 2 muchmore rapidly than the plastic metal isv being extruded therefrom and the pumping in of the molten metal produces a rising of the main-ram I5 and plunger I against the steady extrusion pressure maintained thereon. The upward movement of the main ram I5 thus provides for the expansion of the volume of the container 2 to receive the charge delivered by the auxiliary ram I3. The main ram I5 by its upward movement stores up some of the energy applied by the auxiliary ram and this energy is usedduring the in- 7., p

terval between two deliveries from the auxiliary nated with the rate of extrusion therefrom. The

rate of feed is determined by the speed-of the motor lifiwhich controls the rate of operation of the valve 32. The speed of the motor may be controlled by a hand operated controller II8 of any suitable type. A device is also provided for temporarily stopping the operation of the auxiliary ram I3 should the rate of feed exceed that of extrusion by such an amount as to cause abnormal upward movement of the main ram I5. The valve 42 carries an arm 92 through which passes a rod 33 carrying a slidable collar II9 adjacent to its upper end, and a helical spring I20 placed be-' tween the arm 92 and the collar H3. The lower end of the rod has an oblique surface 94 which cooperates with a correspondingly shaped surface on the piston rod 48 to push the latter into such a position that the piston 50 is brought opposite to the inlet for the pipe 33 and the pressure water cut off from the upper end of the hydraulic ram '3. This occurs when the rod 93 is pushed downwards by contact of its upper end with a fixed stop 95 carried by the frame 73. When the rod 93 is pushed down in this manner, the spring I126 is compressed and the end of the piston rod 48 brought out of contact with the cam 5i so that the valve 42 is no longer operated by the motor 33 and the hydraulic ram 3 is placed out of action until the rod 93 can allow the spring to push the piston rod 48 again into the path of the cam 5i. This occurs when the steady pressure applied to the annular surface 32 of the plunger l pushes the latter downwards and the hydraulic ram 3 is again brought into operation.

- It, will be understood that when the machine is in operation, the plunger i, main ram i5, valve 42 and the motor 36 and the rod 33 all make small upward and downward movements to-' gether, the frame I3 and stop 35 however, remaining stationary.

As pressure is continuously maintained upon the annular surface 33 of the hydraulic ram 3, it follows that if the water exertingpressure upon the upper end of the hydraulic ram 3 be cut off,

' the water acting upon the annular surface 33 of that ram will raise the latter and bring it into itsuppermost position, that is to say, into the position shown in Figure 1.

In the construction shown in Figure 1 the fixed parts comprising the hydraulic cylinder 6, its extension 8, feeding vessel!) and container 2 are in tension and the whole apparatus may be supported from above.

In the construction shown in Figuire 2, an auxiliary ram I3 having ahead Il is adapted to draw molten metal from a feeding vessel 3. through a passage 3I in a block I8 and to deliver the metal to the space within a short conpipe 85.

annular surface 34 during the downward stroke In the construction shown in Figure 2, the main ram I5 and the auxiliary ram I3 are disposed opposite to each other and not concentrically as in Figure 1, the auxiliary ram being arranged to pump molten metal past a ball I0 into 5 the container 2, the lower end of which is closed by the upper endof the main ram I5. Asteady extrusion pressure is'maintained upon the metal in the container 2 by the main ram l5 and plastic metal is extruded from the lower end of the main 1 ram, which is hollow, through a die box 5 which is carried at the lower end of the main ram. The container 2 and the bore in the main ram I5 are maintained filled with metal and when the auxiliary ram I3 pumps molten metal into 14 the container 2, the main ram I5 moves downwards against the steady extrusion pressure, the latter being supplied by a water ram 14.. The latter exerts pressure upon the main ram I5 through a short sleeve 15 which is screwed to The water jacket 66 has an inlet passage 16 and 2 an outlet passage Ii.

The upper end of the container 2 is closed by a block I8 which is screwed into the container and has a central passage for the auxiliary ram I3. Theblock 78 is screwed into the lower end 3 of a hollow block 19 having a bore 83 for the sliding movement of the hydraulic ram 3. The latter works in a cylinder BI disposed partly within the bore 82 of a fixed head 83. The upper end of the cylinder is closed by a plug 83 pro- 3 vided with a passage 35 to which pressure Water can be admitted through a pipe 86. The lower end of the cylinder 8i extends into the bore of a hollow block 31, the lower end of the cylinder being flanged and secured in place by'the 4 block 311 which is held against the head 83. As the fixed parts of the apparatus are in compression, the block l3 may be located by dowel pins 38.

The hydraulic ram 3 has an annular surface 4 38 as in Figure 1 and pressure water is admitted to that surface through passages 83 and 9!) in the cylinder BI and block 33 respectively. Water acting upon the annular surface moves the hydraulic ram 3 and auxiliary ram I3 upwards, 5

the pressure water then being cut ofi from the The pressure is maintained upon the of the hydraulic'ram 3 as in the construction of Figure 1.

The waterjacket 66 takes the thrust exerted v by the water ram 14 and is 'made sufiiciently strong for this purpose. The water jacket supports the furnace 62 and the feeding vessel 9 to which is connected the pipe 56 for the supply of molten metal. The block 18, the bore of which serves as a cylinder for the auxiliary ram I3 and its head It, has a passage III which communicates with v the interior of the. feeding vessel 9.

The auxiliary ram I3 draws molten metal from the feeding vessel through passage 9| and forces it through the lower portion of the bore in the block 18 past the ball I0 into the container 2.

When the-auxiliary ram I3 is pumping metal into the container 2 the parts that move downward are the feeding vessel 9, furnace 62, Water jacket 33, the main ram I5, sleeve 15 .and water ram l3.

Packing rings are provided between the. hy-. draulic ram 3 and the cylinder 8| and air is .which are fixed at their upper ends to the head 83 and to the fixed cylinder for the ram 14 in the manner shown in Figure 3;

The pipe 86 for the inlet of pressure water to the top of the. hydraulic ram 3 will have a valve in it for cutting ofithe supply when the auxiliary ram has reached-the end of its pumping stroke and a pipe will also-be provided for discharging water to waste during the upward stroke of the hydraulic ram 3 and auxiliary ram l3. The valveshown in Figure 1 and arranged as in'Figure 3 may be used. Y

In the construction just described it'will'be understood that the main ram l5 forms a part of the container 2 and that the plastic metal is extruded at the lower end of the-main ram. The container 2 serves'to enclose-the molten metal and a sufllcient lengthof the main ram IE to provide an eifective closing of the lower end of the container. The container can therefore, be made of-short length. The upper end of the container 2 is closed by the block 19 and auxiliary ram l3. Y

In the construction shown in Figure 3, the main ram l5 and the'auxiliary ram ii are arranged concentrically as in Figure 1, but the main ram does not move but is fixed to the head 83 of the press. The container 2 and feeding vessel 9 are formed integrally with each other and make a small downward movement "when molten metal is pumped into: the upper end of the container by the auxiliary ram l3; The lower end of the container 2 carriesa die box 5 and is supported bya hydraulic ram ll. 1 The hydraulic ram 8 works in.a cylinder 8| I which is located in the head 83Jand has a flanged extension IOTwhichsupportsthe main ram l5. The flanged extension is fixed to the head 88 by bolts I03 having -T heads l2l the bolts engaging in slots lfllformed in the head 83. The auxiliary ram l3 has ahead H which works in the bore of the lower portion of the main ram l5 and a bail I is provided at' the lower end of the main ram. The movements-of the container 2, which forms a cylinder for the lower end of the main ram, are small, thevolume of the metal pumped into the container 2 being small compared with the volume of the container; The downward movement of the latter is such that it does not leave the lower end of the main ram l5.- The molten metal is drawn bythe auxiliary ram from the feeding vessel 9 which forms'an extension'of the container 2 intothe lower portion vof -'the main ram l'lthrough a passage I in the main ram, molten metalleaking past the head M on the downward stroke of the auxiliary ram passing back into the feeding vessel 9 through a passage I86 inthe main ram.

Air is excluded from the metal in the feedingvessel by a plate l0! screwed to the upper end of the feeding vessel, "a gland I08 and a packing I89.

The lower part of the container 2 is surrounded bya water jacket 66 having an inlet pipe H0 and anoutlet pipe I. 4 a I 1 The furnace 62 is supported by the container 2 and moves 'with it. The heating and cooling arrangements and'thesupply of molten metal to I in connection with the previous figures, and in eachconstruction the molten metal flows through the pipe 56 under the action of gravity.

-A steady pressure is maintained upon the metal in the container 2 by the fixed main ram I5 in co-operation with the hydraulic ram 14.

Pressure water is supplied to the upper end of the hydraulic ram 3 through the pipe 86 and to the annular surface 34 of the hydraulic ram through a passage H2 in the flanged extension of. the cylinder 8|. Pressure is maintained on the end of the auxiliary ram 3 and on the annular surface 34 simultaneously as in the construction shown in Figure 1. Packing members H3 are provided between the hydraulic ram 3 and the flanged extension I02, water leaking past this packing flowing through a waste pipe- H4.

The operation of the hydraulic ram 3 and auxiliary ram I 3 is controlled by valve apparatus similar to that shown in Figure 1, the stop 95, however, being mounted on a bracket H6 which moves with the container 2, whilst the valve apsparatus itself is mounted on a fixed bracket In each of the constructions described above extrusion of plastic metal can be carried on continuously and air is excluded from contact with all of the metal during the whole of an extmsion operation. The apparatus also avoids the necessity for removing the rains from the container 'for charging and the interruptions in the extrusion operation necessitated thereby. The metal in the press is always maintained under pressure and this pressure can 'be readily maintained while the press is temporarily out of use between two extrusion operations. By maintaining this pressurethe possibility of air leaking into the press is reduced to a minimum. Further, in each of the constructions described the sliding surfaces between the main .ram and the container .are maintained immersed in'molte'n metal and the latter is delivered to the container away from the walls thereof and to such a position that a symmetrical flow. of ,heat and of metal can be obtained; Y

The provision of a'relatively long and narrow tubular container is also of advantage as it facilitates a comparatively rapid transition of the metal from the molten to the plastic condition and accurate control of the temperature conditions required to bring'about this transition.

It will be understood that variations, as regards constructional details, may be made within a the scope of the invention.

What I claim' as my invention is:

1.. An extrusion press for metals comprising a container having an outlet from which metal is extruded, a main ram for exerting a steady pressure upon metal in the container, a; feeding vessel outside the main ram, and an auxiliary ram disposed within the main ram for drawing molten metal from the feeding vessel and delivering it into the container through the main ram and at a place remote from the outlet of the conv tainer, the container and mainand auxiliary rams being co-axially disposed.

'2. An extrusion press for metals com sing a container, a hollow main ram at one nd of the container for exerting a steady pressure upon metal in the container and forming, in effect, a part of the container, a feeding vessel outside the container and anauxiliary ram at the opposite end of the container for delivering molten metalfromthe feeding vessel to thecontainer, the container and main and auxiliary rams being coaxially disposed. Y

3. An extrusion press for metals comprising a container having an outlet from which metal is' extruded, a main ram for exerting a steady pressure upon metal in the container, afeeding vessel enclosing the relative sliding surfaces of the main ram entering one end of the container for exerting a steady pressure upon metal in the container, a sealed feeding vessel enclosing that end of the container, a movable auxiliary ram adapted to work in the main ram, the container and main and auxiliary rams being coaxially disposed,

a hydraulic plunger connected to the main ram, a hydraulic ram connected to the auxiliary ram and adapted to work in the hydraulic plunger and means for reciprocating the hydraulic ram and the auxiliary ram connected thereto for drawing molten metal from the feeding vessel and delivering it to the container through the main ram.

5. An extrusion press for metals comprising a fixed container, a closure member having a bore, at one end of the container, a slidable hollow main ram entering the opposite end of the container, a hydraulic ram connected to the hollow main ram, a feeding vessel surrounding the container, an auxiliary, ram adapted to reciprocate in the bore of the closure member for drawing molten metal from the feeding vessel and delivering it to the container the container and main and auxiliary rams being co-axially disposed, and a hydraulic ram connected tothe.

auxiliary ram. I

6. An extrusion press for metals comprising a movable tubular container, a hydraulic ram disposed at one-end of the container, a fixed hollow main ram entering the other end of the container, a feeding vessel surrounding the main ram, an auxiliary ram adapted to reciprocate within the hollow ram for drawing molten 'metal from the feeding vessel and delivering it to the container through the main ram, the container and main and auxiliary rams-being co-axially disposed and a hydraulic ram connected to the auxiliary ram.

7. An extrusion press for metals comprising a. movable tubular container, a hydraulic ram for exerting pressure upon one end of the container, a fixed hollow main ram entering the other end of thecontainer, a feeding vessel forming a continuation of. the tubular container and surround ing the main ram, an auxiliary ram adapted to reciprocate within the'hollow ram for drawing molten metal from the feeding vessel and delivering it to the container through the main ram, the container and main and auxiliary rams being coaxially disposed, and a. hydraulic ram connected to the auxiliary ram,

8. An extrusion press for metals comprising a fixed cylinder, a hydraulic plunger in the cylinder,-

a hydraulic ram in the plunger, a hollow main ram carried by the hydraulic plunger, an auxiliary ram carried by the hydraulic ram and entering the main ram, 2. non-return valve carried by the main ram; a tubular container entered by the main ram, the container and main and auxiliary rams being co-axially disposed and afeeding vessel carried by the fixed cylinderand fixed tothe container.

9. *An extrusion press for metals comprising a fixed cylinder, a hydraulic plunger in the cylinder, a hydraulic ram in the plunger, a. hollow main ram carried by the hydraulic plunger, an auxiliary ram'carried by the hydraulic ram and entering the main ram; a non-return valve carried by the main ram, a tubular container entered by the main ram, the container and main and auxiliary rams being co-axially disposed, a feeding vessel carried by the fixed cylinder and fixed to the container, means for heating the feeding vessel and means for cooling the container.

10. An extrusion press for metals comprising a fixed cylinder, a hydraulic plunger in the cylinder, a hydraulic ram in the plunger, an extension to the hydraulic plunger, a tubular member on the hydraulic plunger, an auxiliary ram carried by the hydraulic ram and disposed within the tubular member, a non-return valve carried by the tubular member, a fixed tubular main ram entering the extension, a feeding vessel carried by the cylinder and fixed, to the main ram, means for heating the feeding vessel and means for cooling the main ram, the tubular extension and connected to the auxiliary ram, a non-return valve carried by the closure member and disposed within the container, a casing surrounding the main ram and a hydraulic ram acting upon the casing and main ram.

12. An extrusion press for metals comprising a tubular container, a feeding vessel forming a continuation of the container,- a fixed hollow main ram passing through the feeding vessel and entering'the' container, an auxiliary ram in the main ram, the container and mainand auxiliary rams being co-axially dispos'eia non-return valve carried by the main ram, a fixed press head carrying the main ram, a hydraulic ram in the press head connected to the auxiliary ram, a hydraulic i ram acting upon the container, means for heating the feeding vessel and for cooling the-container. 13. An extrusion press for metals, comprising an auxiliary ram, two cooperating tubular members, the ram and the members being coaxially disposed, one of said tubular members serving as a. container for molten metal and having an outlet from which metal is extruded, the other of said tubular members serving as a main ram for exerting a steady pressure upon metal in the tubular member having the outlet, the auxiliary ram serving to deliver molten metal to one of the tubular members. 7

14. An extrusion press for metals, comprising an auxiliary ram, two cooperating tubular members, the ram and the members being coaxially disposed, one of said tubular members serving as a container for molten metal and having an tubular member having the outlet, the auxiliary ram serving to deliver molten metal to one of the tubular members, the volume delivered at each stroke being small compared with the volume of one-of the tubular members.

15. An extrusion press for metals comprising an auxiliary ram, two cooperating tubular members, the ram and the members being coaxially disposed, one of said tubular members serving as a container for molten metal and having an outlet from which metal is extruded, the other of said tubular members serving as a main ram for exerting a steady pressure upon metal in the tubular member having the outlet, a feeding vessel for the auxiliary ram, means for reciproeating the latter for delivering molten metal from the feeding vessel to one of the tubular members, the auxiliary ram having two surfaces of different areas and means for exerting pressure upon both surfaces simultaneously and means for cutting offv the pressure from the surface of larger area while pressure is maintained upon the surface of smaller area.

16. An extrusion press for metals, comprising anauxiliary ram, two tubular members, the ram and the members being coaxially disposed, one of said tubular members serving as a container for molten metal and having an outlet from which metal is extruded, the other of said tubular members serving as a main ram for exerting a steady pressure upon metal in thetubular member having the outlet, a feeding vessel, means for reciprocating the auxiliary ram for drawing molten metal from the feeding vessel and delivering it to one of the tubular members, a valve for controlling the reciprocating'means and a variable speed motor for operating the valve.

17. An extrusion press for metals; comprising an auxiliary ram, two tubular members, the ram and the members being coaxially disposed, one of said tubular members serving as a container for molten metal and having an outlet from which metal is extruded, the other of said tubular members serving as a main ram for exerting a steady pressure upon metal in the said tubular member having the outlet, a feeding vessel,

means .for reciprocating the auxiliary ram to draw molten metal from the feeding vessel and delivering. it to one of the tubular members, a valve for controlling the reciprocating means, a variable speed motor for operating the valve and means controlled by the relative movement of the tubular members for stopping the auxiliary ram if the said relative movement exceedsapredetermined amount and for bringing the auxiliary ram again into operation after metal has been extruded from the tubular member having the outlet.

18. An'extrusion press for metals comprising a fixed cylinder, a first plunger in the said cylinder, means .for exerting a steady pressure upon the first plunger, a second plunger in the first plunger, means for reciprocating the second plunger, a main ram carried by the first plunger,

an auxiliary ram carried by the'second plunger and entering the main ram,.a fixedcontainer entered at one end by the main ram-and having an outlet at its opposite end, and a feeding vessel for the auxiliary ram surrounding that end of the fixed container entered by the main ram, and carried by the fixed cylinder. the auxiliary ram drawing molten metal from the feeding vessel through the main ram and delivering it to the container, the main and auxiliary rams and the container being coaxially disposed.

19. An extrusion press for metals comprising a fixed cylinder, a plunger in the fixed cylinder, means for reciprocating the plunger, a fixed container, a closure member having, a bore atone end of the container and carried by the fixed cylinder, an auxiliary ram carried by the plunger and entering the bore of the closure member, a slidable hollow main ram entering the opposite end of the container, means for exerting a steady pressure upon the main ram, a feeding vessel for the auxiliary ram, surrounding the container, the auxiliary ram drawing molten metal from the feeding vessel through the closure member anddelivering it to the conta ner, the main and auxiliary rams and container being coaxially dispose 20. An extrusion press for metals, comprising the main ram, the main and auxiliary rams and container being coaxially disposed.

21. In an extrusion press for metals, an auxiliary ram and two tubular members, the ram and the members being coaxially disposed, one of said tubular members serving as a container for molten metal to be extruded, one of said members having an outlet fromwhich metal is extruded, and one of'said tubular members serving as a main ram for exerting a steady pressure upon metal in the said tubular .member having the outlet, the auxiliary ram serving to deliver molten metal to one of the tubular members.

22. In an extrusion press for metals, an auxiliary ram and two tubular members, the ram and outlet, the auxiliary ram serving to deliver molten metal to one of the tubular members, the volume delivered at each stroke being small compared with the volume of one of the tubular members.

23. In an extrusion press for metals, an auxiliary ram and two tubular members, the ram and the members being coaxiallydisposed'one ,of said tubular members serving as a container for molten metal to be extruded, one of said members having an outlet from which metal is extruded, and one of saidtubular members serving asa main ram for exerting a steady pressure upon.

metal in the saidtubular member having the outlet, a feeding vessel for the auidliary ram, means for reciprocating the latter for delivering molten metal from the feeding vessel to one of the tubular members, the'auxiliary-ram having two surfaces of different areas and means for exerting pressure upon both surfaces simultaneousiyand means for cutting oif'the pressure from the surface of larger area while pressure is main- .tained upon the surface of smaller area.

24. In an extrusion-press for metals, an auxiliary ram and two tubular members, the ram and the members being coaxially disposed, one of said tubular members serving as a container for molten metal'to he extruded, one of said members the auxiliary ram for drawing molten metal from the feeding vessel and delivering it to one of the tubular members, 'a valve for controlling the reciprocating means and a variable speed motor for operating the valve. I

s 25. In an extrusion press for metals, an auxiliary ram and two tubular members, the ram and the members being coaxially disposed. one of said tubular members serving as a Container for molten metal to be extruded, one of said members having an outlet from which metal is extruded, and one of said tubular members serving as a main ram for exerting a steady pressure upon metal in the said tubular member having the outlet, a feeding vessel, means for reciprocating the auxiliary ram for drawing molten metal from the feeding vessel and delivering it to one of the tubular members; a valve for controlling the reciprocating means, a variable speed motor for operating the valve, and means controlled by relative movement of the two members for stopping the auxiliary ram if the said relative movement exceeds a predetermined amount and for bringing the auxiliary ram again into operation after metal has been extruded from the tubular member having the outlet.

GEORGE THOMAS WILSON GRIEVE.

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