US3357226A - Metal extrusion press with die-assembly locking means - Google Patents

Description

Dec. 12, 1967 SNELL ETAL 3,357,226

METAL EXTRUSION PRESS WITH DI EASSEMBLY LOCKING MEANS Filed March 12, 1965 IN V E N TORS DONALD NOEL SNELL ROBERT KENNETH VALKS I m E ATTORNEYS United States Patent 3,357,226 METAL EXTRUSION PRESS WITH DIE-ASSEMBLY LOCG MEANS Donald N. Snell and Robert Kenneth Vallrs, Dorset, England, assignors to The Loewy Engineering Company Limited, Bournemouth, England, a company-of Great Britain Filed Mar. 12, 1965, Ser. No. 439,256 Claims priority, application Great Britain, Mar. 19, 1964, 11,701/64 8 Claims. (Cl. 72-253) ABSTRACT OF THE DISCLOSURE Describes a metal extrusion press with means to hold the die carrier stationary, when the billet container is moved away from the die at the end of an extrusion, for the purpose of severing the discard from the extrusion.

In most metal extrusion presses, the billet-container and the die-assembly can be moved apart from each other in the axis of the press so as to provide a gap between them in which, after the extrusion of a billet, a shear or saw can be entered for the purpose of severing the extruded product from the billet residue.

After an extrusion, this residue remains in the container bore and adheres firmly to it, so that upon separation of the billet-container and die-assembly, the extruded article, while still connected to the residue, seeks to pull the dieassembly along. This pull can be considerable, particularly in the case of presses using port-hole dies.

In modern extrusion presses, the die-assembly is frequently mounted on a carrier in the form of a wheel or arm rotatable about an axis parallel to and spaced at some distance from the press axis. Presses of this type have a high output and other important advantages. In such presses, the die-assembly is supported in the press frame at a point at some distance from the axis of the press. Hence, when a pull is exerted on the die assembly in the direction of this axis, as is the case upon retraction of the container before the separation of the residue, it is inevitable that the die-assembly and the wheel or rotary arm mounting the assembly are subjected to a bending moment. This is undesirable.

It has been proposed to provide in a metal extrusion press in which the die-assembly is mounted on a rotary arm, movable means which, when in position, lock the die-assembly against pull in the direction of the press axis, and thereby eliminate bending moments due to that pull.

According to one proposal, these locking means comprise a slide which can be moved towards and away from the press axis and which, when moved towards this axis, engages the rotary arm of the die-assembly from the side. This proposal leads to a somewhat bulky and heavy design which, especially in view of the somewhat congested con- 'ditions in the region near the die-assembly, is undesirable. Moreover, the locking of the die-assembly can only take place at one side thereof, and may lead, especially in the case of heavy pulls, to canting of the die-assembly, with the result that excessive pressure may occur at the points of engagement between the die-assembly and the slide.

It is therefore an object of the present invention to provide a metal extrusion press with locking means for the die-assembly which is free from these disadvantages, and which, at the same time, provides a positive retaining hold on the die-assembly against any pull transmitted to it by the extruded article from the container upon its retraction before the severance of thebillet residue.

An embodiment of the invention is described by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a transverse section through a metal extrusion press according to the invention along the line I-I of FIG. 2.

FIG. 2 is a longitudinal section of a part of the extrusion press along the line IIII of FIG. 1.

FIG. 3 is a fragmentary view of parts of FIG. 2 on a larger scale.

The press illustrated in the drawings comprises a stationary platen 2 secured to a main cylinder (not shown) by columns 4, and a billet-container 6 in a containercarrier 8. The container is adapted to co-oper-ate, for the extrusion of a billet, with one of two dies 10, the latter being both mounted in a common carrier 12 rotatable about a shaft 14. The axis of this shaft is laterally spacedapart from the main axis of the press, as seen in FIG. 1.

Each of the two dies belongs to a separate die-assembly; such an assembly comprises, in addition to die 10, a back ing ring 16 located immediately behind the die and mounted in the carrier 12, as well as bolsters 18 and 20 which are interposed between the carrier 12 and the platen 2. The bolster 18 may be removably secured to another bolster 20 or may be located in a slide, not shown, guided on the platen 2 or on a rotary arm. The diametrically opposite ends of the carrier 12 are shaped as twopronged forks (FIG. 1) and a die 10, together wit-h backing ring 16 of its assembly, is entered from the side between the prongs 21 of the carrier.

The mounting of the die-assemblies on a common rotary carrier makes it possible to place one die-assembly in the main axis of the press and between platen 2 and container 6, and the other assembly at the same time at an outside or parking station for exchange or reconditioning of its components. The die-assemblies exchange their respective positions by rotation of the carrier 12 about shaft 14.

A plate 22 is secured by strong bolts 24 to the platen 2, the plate having lugs 26- projecting from it towards the container 6. The bolts 24 are shown in FIG. 2 as passing through the entire length of the platen and being secured at the outside of the platen by nuts. Two pairs of lugs are provided on the plate 22 in the embodiment shown and these pairs are arranged as shown in FIG. 1 diametrically opposite each other and symmetrically with respect to the main press axis. Secured in holes in the lugs 26 of each pair is a pin 28 on which latches 30 are rockably mounted. The pins extend at right-angles to a plane passing through the press axis, so that the latches 30 move in that plane when rocked about the pins 28. Pivot-ably mounted on the platen 2 at 31 are piston-and-cylinder units 32, one for each lug 30, the piston rods being attached at 34 to the latches.

The ends of the latches are formed as hooks 36 which are adapted, as shown in FIG. 2 and more particularly in FIG. 3, to enter into recesses at the container side of the carrier 12 and thus engage from behind shoulders 38 on that carrier. As shown in FIG. 1, the shoulders 38 are formed on the prongs 21.

If an extrusion operation is to be carried out, a billet is placed in the bore of the container 6, and a die-assem-bly with its die 10 is positioned in the press axis, as shown in FIG. 1. Pressure is then applied to the billet by a pressing stem, not shown, whereupon the billet is extruded through the die 11 as is well-known, and thus forms a product which leaves the press through a tunnel it? in the platen 2. After extrusion of the billet has been completed, the pressing stem is withdrawn from the container 6. As well-known in extrusion practice, a certain residual amount of the billet cannot be extruded and remains in the container bore adhering firmly to the wall of that bore. This residue must be severed from the extruded product before the latter can be withdrawn from the press. To this end, the container 6 is retracted from the die-assembly, by means not shown, in, order to make it possible for a cutting device to pass through the extruded article at a point between the container and the die. During the retraction of the container at this stage, the extruded product is anchored to the container by the residue adhering to the wall of the container bore. On the other hand, the product also fitstightly in the dieaperture, so that upon retraction of the container, at strong pull in the direction ofthe container movement is exerted on the die-assembly through the extruded product. In presses fitted with port-hole dies, the area of contact between die and extruded product is considerably greater than with open dies, and therefore the tendency of the die-assembly to follow the container during the latters movement is the more pronounced. The pull exerted by the product acts in the press axis and produces therefore a bending moment on the die-assembly and the carrier 12, since the latter is supported on shaft 14 whose axis is spaced-apart from the press axis.

In the press according to the invention, this pull is counteracted by the latches 30 which, when in their effective position, engage with their books 36 the shoulders 38 of the carrier 12 from behind. The pull on the carrier 12 is thus resisted through the latches 30 which, as described before, are anchored to the platen 2 through the bolts 24, the plate 22 and the lugs 26.

. After retraction of the container 6 from the die-assembly, a length of the extruded product extending between container and die is laid open and a gap is also formed between container and die through which a saw 59 can move and sever the extruded product from the residue in the container bore. The extruded product can then be removed from the press through the tunnel 40.

In some cases, it is desired to sever the residue from the extruded product at a point between the die 19 and the bolster 18. In this event, the latches 30 are locked about their pivots 28 into the positions shown in chain lines in FIG. 3, so that the hooks 36 are disengaged from the shoulder 38. Carrier 12, together with the die-assemblies, can now be moved, by means not shown, in the same axial direction as the container, so that a gap will be formed between the die 10 and the bolster 18 for the entry thereinto of the saw 50 which, of course, must be axially movable.

The die-assembly locking means provided in accordance with the invention may have means for resisting downward thrust on the carrier 12. Such a thrust is, for instance, exerted by a shear 41 (FIG. 2) which is usedinstead of a saw-for cutting the billet residue from the extruded product at the face of the die. The means for resisting downward thrust consist here of tongues 42 formed on the lugs 26, which tongues enter into recesses 44 in carrier 12. (FIG. 3). In this case, the carrier 12 has to be moved axially away from the platen 2 so as to disengage the tongues 42 before the carrier can be rotated.

Prior to the use of the shear 41, the container 6 is retracted from the die-assembly as described before, but the pressing stem is left in the advanced position so that the billet residue is forced out of the container bore upon retraction of the container. The shear 41 is then lowered from the position in FIG. 2 and cuts along the face of die 10, thus severing the residue adhering to that face from the extruded product.

The invention is capable of embodiments other than those shown and described with reference to the accompanying drawings. The number of latches 30 and their distribution around the press axis may be altered, but the latches should preferably be spaced at equal distances from each other and symmetrically around and with respect to a plane passing through the press axis. Instead of pivotally mounting the piston-and-cylinder units 32 on the platen 2, these units may be fixed on the platen and articulated links be provided between the units and the pivots 34. The latches 34, instead of being pivoted to the platen 2 may be pivoted to the carrier 12. and co-operate with their hooked ends with shoulders on the platen or a partsecured to it.

The main feature of the invention is seen in the provision of a plurality of latches symmetrically disposed around and with respect to a plane passing through the press axis and adapted to anchor to the platen of an extrusion press a carrier for die-assemblies, which carrier is supported on an axis spaced-apart from the press axis.

We claim:

1. A metal extrusion press, having a stationary platen, a billet container, movable along the press axis, and a carrier for a die-assembly, said carrier being arranged between platen and container and supported for rotation about an axis parallel to the press axis, and in which retractable :means are provided for holding said carrier against movement along the press axis in the direction of said container, said means comprising a plurality of retractable latches mounted on pivots and symmetrically disposed around and with respect to a plane passing through the press axis and engaging said carrier at points on the container side of said carrier.

2. A metal extrusion press according to claim 1, in which said latches are formed at their ends with hooks disposed between said platen and said carrier, said hooks being pivoted to one of the two last-mentioned parts and adapted to be moved in locking engagement with the other part.

3. A metal extrusion press according to claim 1, in which the latches are pivoted to lugs projecting from the platen.

4-. A metal extrusion press according to claim 3, in which the lugs are arranged on a separate plate secured to the platen by bolts passing through the platen.

5. A metal extrusion press according to claim 2 in which the hooks on the latches are adapted to enter behind shoulders formed on the carrier.

6. A metal extrusion pres-s according to claim 1, in which cylinder units are mounted on the platen for rock ingthe latches about their pivots.

7. A metal extrusion press according to claim 1, in which the latches have means for resisting downward thrust on the die-assembly carrier.

8. A metal extrusion press according to claim 7, in which the means provided on the latches for resisting downward thrust consist of tongues formed on the lugs in which the latches are pivotally mounted.

References Cited UNITED STATES PATENTS 2,757,794 8/1956 Walgren 72-263 X 3,147,863 9/1964- Rosenthal 72-255 FOREIGN PATENTS 944,251 12/1963 Great Britain. CHARLES W. LANHAM, Primary Examiner,

K. C. DECKER, Examiner.

Claims (1)

1. A METAL EXTRUSION PRESS, HAVING A STATIONARY PLATEN, A BILLET CONTAINER, MOVABLE ALONG THE PRESS AXIS, AND A CARRIER FOR A DIE-ASSEMBLY, SAID CARRIER BEING ARRANGED BETWEEN PLATEN AND CONTAINER AND SUPPORTED FOR ROTATION ABOUT AN AXIS PARALLEL TO THE PRESS AXIS, AND IN WHICH RETRACTABLE MEANS ARE PROVIDED FOR HOLDING SAID CARRIER AGAINST MOVEMENT ALONG THE PRESS AXIS IN THE DIRECTION OF SAID CONTAINER, SAID MEANS COMPRISING A PLURALITY OF RETRACTABLE LATCHES MOUNTED ON PIVOTS AND SYMMETRICALLY DISPOSED AROUND AND WITH RESPECT TO A PLANE PASSING

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