US3620064A

US3620064A - Extrusion presses

Info

Publication number: US3620064A
Application number: US838568A
Authority: US
Inventors: Ronald John Elger; Ian Lewis Cameron
Original assignee: Fielding Plant Design Ltd
Current assignee: Fielding Plant Design Ltd
Priority date: 1968-07-05
Filing date: 1969-07-02
Publication date: 1971-11-16
Anticipated expiration: 1988-11-16
Also published as: FR2012401A1; DE1933839A1; GB1263907A

Abstract

AN EXTRUSION PRESS HAVING TWO OR MORE MAIN CYLINDERS IN WHICH THE FREE SPACE BETWEEN THE CYLINDERS IS USED TO ACCOMMODATE GUIDE MEANS FOR THE MOVING CROSSHEAD. INDIVIDUAL SUPPORTING MEANS ARE PROVIDED FOR EACH CYLINDER THROUGH WHICH THE WEIGHT OF HAT CYLINDER IS INDEPENDENTLY TRANSMITTED TO THE PRESS-BED.

Description

NOV, 16, 1971 RJ, ELGER ETAL 3,620,064

EXTRUSION PRESSES Filed July E, 1969 5 Shoots-Shoot 1 V 1h u m w: E Q" e* Hi C) "r N --g/ N l 'Ol j sa y l @s mag lL Nov. 16,1971 RJ. ELGER ErAL 3,620,064

' EXTRUSION PRESSES Filed July 2, 1969 5 Sheets-Sheet 2 Nov. 16, 1971 R, J, ELC-3ER ETAL 3,620,064

EXTRUSION PRESSES Filed July s, 1969 I 5 sheets-sheet EXTRUSION PRESSES 5 Sheets-Shea?I 4 Filed July 2, 1969 Umm. N

Nov. 16, 1971 R 1 ELGER EIAL 3,620,064

ExTRUsIoN PRESSES Filed July a, 1969 5 sheets-sheet s United States Patent O U.S. Cl. 72-272 18 Claims ABSTRACT F THE DISCLOSURE An extrusion press having two or more main cylinders in which the -free space between the cylinders is used to accommodate guide means for the moving crosshead. Individual supporting means are provided for each cylinder through which the weight of that cylinder is independently transmitted to the press-bed.

This invention relates to extrusion presses.

According to the present invention there is provided an extrusion press having two or more substantially parallel main cylinders grouped symmetrically to dene a free space therebetween, the cylinders being arranged, in use, to drive the moving crosshead of the press, the said crosshead carrying an extension disposed in the said free space, the extension being engageable with guide means to ensure true longitudinal movement of the said crosshead relative to the press axis, and the weight of the cylinders being transmitted to the press-bed without the use of conventional cylinder crossheads. The guide means may be arranged so that .guiding of the moving crosshead is effected independently of misalignment of, and/or small differences in force exerted by the main cylinders. In this case, the guide means may comprise one or more longitudinally extending slideways secured to the press-bed. Alternatively, the guide means may comprise one or more longitudinally extending slideways secured on the facing sides of the two or more main cylinders. In both cases the extension may be provided with one or more guide surfaces for engaging the or a corresponding slideway.

The moving crosshead itself may be provided with guide surfaces engageable with corresponding longitudinally extending Aguide members secured to the pressbed. A pair of guide members may be provided which are arranged on opposite sides of the press-bed.

Advantageously, the moving crosshead and the main cylinder rams are connected, the connection being designed with suicient free movement to ensure that guiding of the moving crosshead is effected independently of misalignment of, and/or small differences in force exerted by the main cylinders.

The extension may be constituted by a stalk-like member which can be either integral with or secured to the mowing crosshead.

When the press is used for tube extruding the stalklike member may be constructed to permit throughpassage of a mandrel holder. Further, one or both ends of the stalk-member may be provided with means for limiting the stroke ofthe press mandrel relative to the press stem. The limit means may comprise a longitudinally adjustable, non-rotatable bush surrounding the mandrel holder, said'bush being engageable with a stop member secured to the mandrel holder. The bush may be eX- ternally screw-threaded and held in the stalk-member by a captive nut, the nut being disposed in the stalk-member so that rotation thereof provides axial adjustment of the bush.

3,620,064 Patented Nov. 16, 1971 Furthermore, means may be provided for locking the mandrel holder against relative axial movement with respect to the die. The locking means may be constituted by a transversely movable locking member mounted on a main cylinder and by a stop member provided on the mandrel holder, the axial position of the stop-member on the holder being arranged so that when, in use, the mandrel is in its extruding position, the locking member may be moved to engage the stop member. The stop member may be mounted on the holder so that it can be moved axially into a number of xed positions thereon. A locking member may be provided on each of the main cylinders.

The invention will now be described with reference to the accompanying drawings, of which:

FIG. 1 is a schematic side elevation, partly in section, of a irst embodiment of the invention;

FIG. 2 is a plan view, partly in section, of the embodiment of FIG. l;

FIG. 3 is a section taken at III-III of FIG. l;

FIG. 4 is a section taken at IV-IV on FIG. 1;

FIG. 5 is a section of one half of a second embodiment of the invention, viewed from above;

FIG. 6 is a vertical section through the second embodiment of the invention, along the line VI-VI of FIG. 5; and

FIG. 7 is a diagrammatic sectional plan view of a press including mandrel-arrest equipment.

The embodiment illustrated in FIGS. 1 to 4 is a tube extrusion press having two main cylinders, and includes piercer gear.

It will be seen from the drawings that the conventional cylinder crosshead has been dispensed with, the pair of main

hydraulic cylinders

2a and 2b being supported on the press-bed 1. Consequently, there will be significant savings in weight and cost of the press. The

cylinders

2a and 2b are disposed in spaced side-by-side relation and the

rams

3a and 3b carry a moving cross-head 4 on which is mounted a hollow extrusion stern 5. The moving cross-head 4 is slidably mounted on the bed 1, by means of vertical and horizontal guide members 6 and 7 respectively, for movement parallel to the longitudinal axis of the press, corresponding guide surfaces 6a, 7a being secured to the bed of the machine.

The rear face of the moving cross-head 4 carries a central rearwardly extending hollow stalk 8, the free end of which is formed with a downwardly extending guide member 9 running on a longitudinal guide track 10 secured to the bed 1 of the machine midway between the

main cylinders

2a and 2b. The presence of this guide member ensures that slewing of the stem -5 will be prevented in the event that uneven operation of the main rams occurs for any reason.

Return of the moving cross-head is effected by four return cylinders 11 mounted on the main cylinders with their rams 12 secured to the cross-head.

As the illustrated machine is a tube extrusion press, piercer gear is provided, and is accommodated partly in the space between the two main cylinders.

The piercer cylinder 13:` is mounted at one end on a iixed cross-head 14 supported on a supplementary machine bed 15, and connected to the

cylinders

2a, 2b by laterally disposed tie rods 16. The other end of cylinder 13 has an extrusion 17 which engages in a support bracket on the bed 115. The iixed cross-head 14 also carries vertically aligned sleeves 1-8 which serve as adjustable stroke limits for a pair of mandrel-arrest rods 19 secured at one end to a piercer cross-head 20 which slides on the guide track 10 under the action of piercer ram 13a and at their other end to a support trolley 21. The mandrel holder 22 of the machine is mounted on the piercer cross-head 20, and extends through the hollow extension 8 and into the rear of cross-head 4 in which it is supported by a bush 23. A mandrel adapter 24 is screwed into the end of holder 22, and extends through the cross-head 4 to support the mandrel in the extrusion stem 5.

It will be seen from the drawings and the foregoing description that the guiding of the moving cross-head 4 by the

surfaces

6a, 7a and 10 is independent of misalignment of, and/or small differences in force exerted by the

main cylinders

2a and 2b. To maintain this independence during operation, the connection between the

rams

3a and 3b and the moving cross-head 4 is designed with suflicient free movement to accommodate the misalignment and/or unequal cylinder forces encountered in practice. Thus, alignment and adjustment of the moving cross-head is substantially unatected by such effects as wear of the main ram bushes, which cause variation in the alignment of the main rams.

The second embodiment of the invention, illustrated in FIGS. 5 and 6, is also a tube extrusion press, but has a guide stem integral with the moving cross-head and shows mandrel stroke limiting arrangements. (Reference numerals, where possible, correspond to those used in FIGS. l to 4.)

The general layout of the press is similar to that of the rst embodiment, and in particular the cylinders are again supported on the press-bed instead of by a conventional cylinder crosshead. Two main rams, of which one is shown at 3a, carry a moving cross-head 4 which supports an extrusion stem 5. The cross-head moves on a pair of spaced guides (not shown, but similar to 6, 7 in the first embodiment), while the third set of guides is provided at the end of an integral rearward extrusion 8 of the moving cross-head. This extension is of open trough-like form, and has its free end closed by a vertical wall 26 bored at 27 and provided with a bush 28 to serve as a bearing for the mandrel holder 22. The forward end of the mandrel holder is carried in bushing 23 in the cross-head 4, and supports a piercer adaptor and mandrel as in the case of the tirst embodiment,

The rear end of the extension 8 is provided with vertical and

horizontal guide members

29 and 30 respectively, engaging

corresponding guide surfaces

31, 32 mounted on the facing wall of the two

main cylinders

2a, 2b, -giving guidance which is independent of the misalignment of, and/or small differences in force exerted by the main rams as in the case of the first embodiment.

In extrusion of tubes, it is necessary to limit the stroke of the mandrel relative to the stem. In this ernbodiment of the invention, this can be achieved within the space between the main rams.

At each end of the trough-like cavity within the moving cross-head extension there is a

captive nut

33a, 33b retained by a Collar 34a, 34h. Each nut is provided with sprocket teeth 35 for rotation by a chain having access through the open trough, and engages with external screw threading on a corresponding bush 36a, 361) surrounding the piercer holder. Thus, rotation of either

nut

33a or 33b causes axial adjustment of the corresponding bush. Rotation of the bushes is prevented by keys engaging keyways in the extension 8. It will be seen from FIG. 5 that the mandrel holder has a central integral collar 3'7 which, by its abutment with the bushes 36a, 36]), limits the stroke of the piercer assembly relative to the stem. This arrangement obviates the need to provide space for such limit adjustments at a position axially beyond the main ram cylinders. Another item of equipment located within the axial extent of the main cylinder assembly is the worm and pinion drive 38 used to rotate the piercer holder. It is of course possible to provide either forward or rearward stroke limitation alone.

Means have been described above for limiting the stroke ot' the mandrel relative to the moving cross-head 4 and the stem. FIG. 7 illustrates mechanical means for arresting the mandrel relative to the die, when extrusion is caried out using a stationary mandrel. Such means are essential when a stepped-mandrel 38 is employed, as shown, since a backward force is exerted by the material being extruded on the annular surface of the stepped portion of the mandrel. Between the stroke-limiting collar 39 and the piercer cylinder 40 the piercer holder 41 is formed with a screw-threaded portion 42. Screwed onto this portion is a stop-nut 43 the axial position of which is set so that when the mandrel 38 is in its extruding position it abuts flanges 44 formed on a pair of laterally disposed housings 45. Mounted in the housings 45 are two hydraulic cylinders 46 which operate a pair of locking members 47 to engage the stop-nut 42, as shown in FIG. 7, when the mandrel is in its extruding position. Consequently, the backward force exerted on the mandrel, which becomes acute towards the end of extrusion when the forward frictional drag of the billet on the mandrel is reduced, will be effectively resisted by locking the mandrel holder as described.

It will be understood that because the two press constructions described above are very similar, parts of one can be readily replaced or interchanged with parts of the other. Thus, for example, the rear end of the extension 8 could be provided with a guide member similar to the member 9 instead of the

guide members

29 and 30. Again the extension 8 could be replaced by an extension similar in form to 8 in which case the mandrel stroke limiting means could also be interchanged` These are only examples of what can be done and other interchanges or replacements will be readily apparent to one skilled in the art.

It will also be evident that the invention is not limited to tube-extruding presses and is equally applicable to rod-extrusion where no piercer gear will be required. In the case of a tube press, however, an additional advantage is achieved since the free space between the main cylinders can be used for accommodating the piercer gear, thus keeping the overall length of the press to an absolute minimum.

We claim:

ll. An extrusion press having two or more substantially parallel main cylinders grouped symmetrically to define a free space therebetween, the cylinders being arranged, in use, to drive the moving crosshead of the press, the said crosshead carrying an extension disposed in the said free space, the extension being engageable with guide means to ensure true longitudinal movement of the said crosshead relative to the press axis, and said press comprising individual supporting means for each cylinder through which the weight of that cylinder is independently transmitted to the press-bed.

2. An extrusion press according to claim 1, in which the guide means are arranged so that guiding of the moving crosshead is effected independently of misalignment of, and/or small diiferences in force exerted by the main cylinders.

3. A press as claimed in claim 1. in which the guide means comprise one or more longitudinally extending slideways secured to the press-bed.

4. A press as claimed in claim 3, in which the extension is provided with one or more guide surfaces for engaging the or a corresponding slideway.

5. A press as claimed in claim 1, in which the guide means comprise one or more longitudinally extending slideways secured on the facing sides of the two or more main cylinders.

6. A press as claimed in claim 5, in which the extension is provided with one or more guide surfaces for engaging the or a corresponding slideway.

7. A press as claimed in claim 6, in which a pair of said guide members are provided and are arranged on opposite sides ofthe press-bed.

8. A press as claimed in claim 1, in which the moving crosshead itself is provided with guide surfaces engageable with corresponding longitudinally extending guide members secured to the press-bed.

9. A press as claimed in claim 1, in which the moving crosshead and the main cylinder rams are connected, the connection being designed with sufficient free movement to ensure that guiding of the moving crosshead is effected independently of misalignment of, and/or small differences in force exerted by, the main cylinders.

10. A press as claimed in claim 1, in which the extension is constituted by a stalk-like member which can be either integral with or secured to the moving crosshead.

11. A press as claimed in claim 10, in which the stalklike member is constructed to permit through-passage of a mandrel holder when the press is used for tube extruding.

12. A press as claimed in claim 11, in which one or both ends of the stalk member are provided with means for limiting the stroke of the press mandrel relative to the press stem.

13. A press as claimed in claim 12, in which said limit means comprise a longitudinally adjustable, non-rotatable bush surrounding the mandrel holder, said bush being engageable with a stop member secured to the mandrel holder.

14. A press as claimed in claim 13, in which the bush is externally screw-threaded and is held in the stalk member by a captive nut, the nut being disposed in the stalk member so that rotation thereof provides axial adjustment of the bush.

15. A press as claimed in claim 11, in which means are provided for locking the mandrel holder against relative axial movement with respect to the die.

16. A press as claimed in claim 15, in which the locking means are constituted by a transversely movable locking member mounted on a main cylinder and by a stop member provided on the mandrel holder, the axial position of the stop member on the holder being arranged so that when, in use, the mandrel is in its extending position, the locking member may be moved to engage the stop member.

17. A press as claimed in claim 16, in which the stop member is mounted on the holder so that it can be moved axially into a number of fixed positions thereon.

18. A press as claimed in claim 17, in which a locking member is provided on each of the main cylinders.

References Cited UNITED STATES PATENTS 638,808 12/1899 Holinger 72-272 1,548,457 8/ 1925 Greayer. 2,075,803 4/1937 Dingl et al. 72-272 2,778,495 l/1957 Krause 72--272 3,334,507 8/l967 Green et al 72-272 3,350,911 ll/l967 Groos 72-272 GERALD A. DOST, Primary Examiner.

.'U.S. Cl. XR. 72-25 3