GB1579423A

GB1579423A - Hydraulic presses

Info

Publication number: GB1579423A
Application number: GB2974076A
Authority: GB
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1976-07-16
Filing date: 1976-07-16
Publication date: 1980-11-19
Also published as: FR2358218B1; FR2358218A1; DE7721553U1; IT1083898B; DE2731055A1

Description

(54) IMPROVEMENTS IN OR RELATING TO HYDRAULIC PRESSES (71) We, MANNESMANN AKTIEN- GESELLSCHAFT, a body corporate organised under the laws of Germany (Fed.

Rep.) of Mannesmannufer 2, 4000 Dusseldorf, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to hydraulic presses and especially Ito presses used for thickening the wall of an end portion of a pipe.

In the production of some casing, tubing and drill pipes it is necessary to thicken the wall of the pipe at an end portion, by upsetting, to iprovide end portions suitable for either external or internal threading or for welding.

Known press designs for this operation alre of a 'C' frame type. The pipe end portion to be upset is gripped between circular split dies, which also serve to determine the external shape of the pipe end portion during the upsetting operation. The lower half of the split die is 'mounted. in a fixed die support which ils supported on thle lower arm of the 'C' frame. The upper half of the split die is mounted in a moving die support which may be driven up and down rby a hydraulic clamping 'ram. This hydraulic ram sildes in a cylinder which is fixed to the upper arm of the 'C' frame.

After the upper half die has been lowered onto a pipe situated in the lower half die the force from the clamping ram is applied to the die set by t'he moving die support to clamp the pipe. The end portion of the pipe, which is heated prior to loading in the die, is upset by applying an axial load to the end face of the pipe using a stepped mandrel.

The load for the upsetting operation is provided by a hydraulic ram acting on the end of the 'stepped mandrel. This hydraulic ram slides in a cylinder which is fixed to the back of the 'C' frame.

The present invention provides a hydraulic press folr tubular workpieces and comprising two die supports, a hydraulic cylinder/ram assembly for effecting movement lof one of the supports ,towards the other 'support, and two sets of split dies carried by the supports, one die set being positioned on one side of a plane containing the axis of the cylinder and the other set being positioned on the other side of that plane, wherein two abutment means are provided, one abutment means being arranged on that side of one of the die sets remote from the plane, and the other abutment means being arranged on that side of the other die set remote from the plane, the abutment means being so arranged that when a workpiece is damped in one die set the supports engage through the abutment means which is closer to the other die set.

The press according to the invention can be used to upset the end portion of a pipe in two operaXtions. Thus the pipe can be clamped between one set of the dies and its end portion upset to an intermediate size.

The pipe can then be removed from the said one set and damped in the other set of dies and its end portion upset to another size.

The apparatus is particularly useful, therefore, where the degree of upsetting required would be difficult, if not impossible, to achieve in a single die set.

because the arrangement of the abutment means ensures that the supports engage as aforesaid, eccentric Ireactions, which would otherwise be applied to the said one support and hence to the 'press structure when a tubular workpiece is clamped in a die set arranged to one side of the Isaid plane, can he reduced.

Preferably, the distance between a respective abutment means and the plane is greater than the distance between the plane and the die set which is on 'the other side of the plane from that abutment means. In consequence, the load induced in the said one support by the cylinder/ram assembly to provide a given applied clamping force can be minimized and, as a result, the size of the supporting structure can be reduced.

To 'reduce the clamping force to its minimum value for a given size of support it is of advantage if the two abutment means are arranged at the ends of the supports.

It is preferred if the said one support is attached to the cylinder /ram assembly for pivotal movement about an axis at right angles to the axis of the cylinder, the two axes being contained by the said plane. In this way, the press can handle workpieces of varying diameters, the pivotal connection allowing angular movement of the said one support.

In order to produce a correctly distributed clamping force on the workpiece it is desirable to maintain the supports substantially in parallelism during clamping. In this case it is still preferred to use the aforesaid pivotal connection because in many instances it will then be unnecessary to have adjustable abutment means or if adjustment is provided it will only be necessary to have the abutment means adjustable from an inopara- tive to an operative position prior to clamp ing. This is because the abutment means can be so arranged that for a given range of tolerances in workpiece diameter the supports will be maintained substantially in palralleXl- ism, any slight tilting of the said one support being taken up by the pivotal connection.

Clearly, if the range lof work.piece diameters is increased then the degree of adjustment of the abutment means will have to be increased if substantial parallelism between the supports is to be maintained.

Further it is also possible, as an altema itive, to dispense with the pivotal connection and to rely solely on adjustment of the abutment means. In this case, however, it is essential that the adjustment of the abutment means is accurately sent prior to clamp inS'to achieve strict parallelism of the supports during clamping because otherwise eccentric reactions will be applied to the said one support.

The split dies in each set are arranged in facing surfaces of the supports and advantageously each of the abutment means projects from a respective one of the surfaces.

'Preferably, the degree to which each abutment means projects from the surface is adjustable.

Advantageously, the abutment means comprises four members, two for each support, each member projecting from the surface of its support and being engageable with a respective abutment member on the other support.

In this case the degree to which at least one of each pair of engageable abutment members Iprojects from the surface of its support may be adjustable.

Each of the Isaid one abutment members may, with advantage be of elongate wedges like form and longitudinally movable to increase or decrease the degree to which the member projects from the surface.

The present invention also provides a hydraulic press for tubular workpieces and comprising two die-supports, a hydraulic cylinder/ram assembly for effecting movement of one of the supports towards the other support the said one support being attached to the cylinder/ram assembly for pivotal movement about an axis at right angles to the axis of the cylinder, and two sets of split dies carried by the supports, one die set being positioned on one side of a plane containing, the 'said axes and the other set being positioned on the other side of that plane, wherein two abutment means are provided, one abutment means being arranged on that side of one of the die sets remote from the plane, and. the other abutment means being arranged on that side of the other die set remote from the plane, the abutment means being equispaced from the plane, and the die sets being equispaced from the plane, and the abutment means being so arranged that when a workpiece is clamped in one die set the supports engage through the abutment means which is closer to the other die set.

The present invention further provides la method of upsetting an end portion of a tubular workpiece using a press constructed in accordance with the invention, the method comprising clamping the workpiece in one of the die sets, performing an upsetting operation on an end portion of the work piece, removing the workpiece from the said.

one die inset, clamping it in the other die set, and performing a further upsetting operation on the end portion of the workpiece.

A pipe upsetting press constructed in accordance with the invention will now be described, by way of example onlv, with reference to the accompanying drawings of which: Fig. 1 is a front elevation of the press; Fig. 2 is a section of the press taken along the line A-A in Fig. 1; Fig. 3 is an enlarged view of parts of the press shown in Fig. 1; Fig. 4 is a view similar to Fig. 3 but with the parts in a different position; Fig. 5 is an enlarged view similar to Fig.

3 but with modifications; and Fig. 6 is a view along the line B-B of Fig. 5.

Referring to the accompanying drawings, a press frame 1 comprises two 'C' shaped plates 2 held in fixed spatial relationship by bolts 3 and diaphragms 4.

Mounted within the opening in the 'C' frame is a lower fixed die support 5 and an upper moving die ,suppo'rt in the form of a clamping crosshead 6. Two pairs of split dies 7 and 8 are mounted in the supports 5 and 6. A clamping Iram 9 is connected to the moving dies support 6 by a spherical joint 9' and is housed. within cylinder 10 which is connected to the press frame 1 by bolts (not shown). Stroke limit pads 11 and 12, and 13 and 14 are provided at the ex tremities of the fixed and moving die supports.

Two upsetting mandrels 15 are provided, one in line with each lower half die. Each upsetting mandrel 15 is fixed to a respective one of two moving crossheads 16 each of which is connected to a respective one of two upsetting rams 17. The rams 17 slide within cylinders 18 which are connected to the press frame by bolts (not shown). Alternatively, the upsetting mandrels 15 may be mounted on a common moving crosshead with a single upsetting ram and cylinder.

In operation, conveying means (not shown) transport a pipe 19 (Fig. 3) into one lower die half 7. The moving die support 6 is lowered until the upper die half 8 comes into contact with the pipe (Fig. 4).

Oil under Ipsressulre from a pressure source (not shown) is supplied via pipe 20 to the clamping cylinder 10, and the moving die support 6 descends until further movement is prevented by the pipe 19 and the stroke limit pads 11 and 12 (see Fig. 4). The pipe 19 is thus clamped within the die orifice as the stroke limit pads 13 and 14 are not in mutual contact. With the pipe 18 clamped the die support 6 may assume a ve;ry small angle to the horizontal plane. However, because the ram 9 is connected to the die support assembly by the spherical joint 9', which accepts slight angular movement of the crosshead 6, transmission of any bending forces to the clamping cylinder ram 9 is prevented.

The press is so arranged that the dies 7, 8 are closer to the centreline of the clamping ram 9 than the stroke limit pads 11, 12 and 13, 14, the dies and the pads being symmetrically disposed relative to that centreline. The load from the clamping ram 9 will therefore be resisted by the pipe 19 and the stroke limit pads furthest from the die in use (in :the present case the pads 11 and 12) in inverse proportion to their respective distances from the clamping ram centreline.

However, the load transmitted to the two sides of the press frame at 21 and 22 (Fig.

4) will be equal.

With the pipe 19 clamped the appropriate upsetting crosshead 16 is advanced and the end portion of the pipe is partially upset by one of the stepped mandrels '15.

After the partial upsetting operation in the first die the pipe 19 is released by raising the moving die support 6. The pipe 19 is transported to the other die by conveying means (not shown).

The moving die support is again lowered to clamp the pipe 19 but this time the die support assumes a very small angle in the opposite direction as the stroke limit pads 13 and 14 come into contact and the ppe is clamped within the second pair of split dies.

The end portion of the pipe 19 is then completely upset using the other stepped mandrel 15.

Figs. 5 and 6 illustrate modified stroke limit pads 23 and 24 which can be raised and lowered by a small amount. For the sake of example, the stroke limit pads 23 and 24 are shown as wedges which can be moved horizontally by the hydraulic cylinders 25 and 26. By moving the wedges horizontally a small vertical movement of their top faces is achieved, thus bringing the appropriate stroke limit into operation.

'With this design the stroke limit pad remote from the die set in use can be raised so that it is possible for the desired loading on the pipe to be achieved without the moving die support 6 taking up an angular position. However, because of the tolerances involved it is preferred, if the moving die support 6 is connected to the clamping ram 9, for example by a spherical joint, to allow for angular movement of that die support.

WAT WE CLAIM IS: 1. A hydraulic press for tubular workpieces and comprising two die supports, a hydraulic cylinder/ram assembly for effecting movement of one of the supports towards the other support, and two sets of split dies carried by the supports, one die set being positioned on one side of a plane containing the axis of the cylinder and the other set being positioned on the other side of that plane, wherein two abutment means are provided, one abutment means being arranged on that side of one of the die sets remote from the plane, and the other abutment means being arranged on that side of the other die set remote from the plane, the abutment means being so arranged that when a workpiece is clamped in one d.ie set the supports engage through the abutment means which is closer to the other die set.

2. A press as claimed in claim 1, in which the distance between a respective abutment means and the plane is greater than the distance between the plane and the die set which is one the other side of the plane from that abutment means.

3. IA press as claimed in claim 1 or claim 2, in which the two abutment means are arranged at the end of the supports.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

a press frame 1 comprises two 'C' shaped plates 2 held in fixed spatial relationship by bolts 3 and diaphragms 4.

Mounted within the opening in the 'C' frame is a lower fixed die support 5 and an upper moving die ,suppo'rt in the form of a clamping crosshead 6. Two pairs of split dies 7 and 8 are mounted in the supports 5 and 6. A clamping Iram 9 is connected to the moving dies support 6 by a spherical joint 9' and is housed. within cylinder 10 which is connected to the press frame 1 by bolts (not shown). Stroke limit pads 11 and 12, and 13 and 14 are provided at the ex tremities of the fixed and moving die supports.

Two upsetting mandrels 15 are provided, one in line with each lower half die. Each upsetting mandrel 15 is fixed to a respective one of two moving crossheads 16 each of which is connected to a respective one of two upsetting rams 17. The rams 17 slide within cylinders 18 which are connected to the press frame by bolts (not shown). Alternatively, the upsetting mandrels 15 may be mounted on a common moving crosshead with a single upsetting ram and cylinder.

In operation, conveying means (not shown) transport a pipe 19 (Fig. 3) into one lower die half 7. The moving die support 6 is lowered until the upper die half 8 comes into contact with the pipe (Fig. 4).

Oil under Ipsressulre from a pressure source (not shown) is supplied via pipe 20 to the clamping cylinder 10, and the moving die support 6 descends until further movement is prevented by the pipe 19 and the stroke limit pads 11 and 12 (see Fig. 4). The pipe 19 is thus clamped within the die orifice as the stroke limit pads 13 and 14 are not in mutual contact. With the pipe 18 clamped the die support 6 may assume a ve;ry small angle to the horizontal plane. However, because the ram 9 is connected to the die support assembly by the spherical joint 9', which accepts slight angular movement of the crosshead 6, transmission of any bending forces to the clamping cylinder ram 9 is prevented.

The press is so arranged that the dies 7, 8 are closer to the centreline of the clamping ram 9 than the stroke limit pads 11, 12 and 13, 14, the dies and the pads being symmetrically disposed relative to that centreline. The load from the clamping ram 9 will therefore be resisted by the pipe 19 and the stroke limit pads furthest from the die in use (in :the present case the pads 11 and 12) in inverse proportion to their respective distances from the clamping ram centreline.

However, the load transmitted to the two sides of the press frame at 21 and 22 (Fig.

4) will be equal.

With the pipe 19 clamped the appropriate upsetting crosshead 16 is advanced and the end portion of the pipe is partially upset by one of the stepped mandrels '15.

After the partial upsetting operation in the first die the pipe 19 is released by raising the moving die support 6. The pipe 19 is transported to the other die by conveying means (not shown).

The moving die support is again lowered to clamp the pipe 19 but this time the die support assumes a very small angle in the opposite direction as the stroke limit pads 13 and 14 come into contact and the ppe is clamped within the second pair of split dies.

The end portion of the pipe 19 is then completely upset using the other stepped mandrel 15.

Figs. 5 and 6 illustrate modified stroke limit pads 23 and 24 which can be raised and lowered by a small amount. For the sake of example, the stroke limit pads 23 and 24 are shown as wedges which can be moved horizontally by the hydraulic cylinders 25 and 26. By moving the wedges horizontally a small vertical movement of their top faces is achieved, thus bringing the appropriate stroke limit into operation.

'With this design the stroke limit pad remote from the die set in use can be raised so that it is possible for the desired loading on the pipe to be achieved without the moving die support 6 taking up an angular position. However, because of the tolerances involved it is preferred, if the moving die support 6 is connected to the clamping ram 9, for example by a spherical joint, to allow for angular movement of that die support.

WAT WE CLAIM IS: 1. A hydraulic press for tubular workpieces and comprising two die supports, a hydraulic cylinder/ram assembly for effecting movement of one of the supports towards the other support, and two sets of split dies carried by the supports, one die set being positioned on one side of a plane containing the axis of the cylinder and the other set being positioned on the other side of that plane, wherein two abutment means are provided, one abutment means being arranged on that side of one of the die sets remote from the plane, and the other abutment means being arranged on that side of the other die set remote from the plane, the abutment means being so arranged that when a workpiece is clamped in one d.ie set the supports engage through the abutment means which is closer to the other die set.
2. A press as claimed in claim 1, in which the distance between a respective abutment means and the plane is greater than the distance between the plane and the die set which is one the other side of the plane from that abutment means.
3. IA press as claimed in claim 1 or claim 2, in which the two abutment means are arranged at the end of the supports.
4. A press as claimed in any one of

claims 1 to 3, in which the said one support is attached to the cylinder/ram assembly for pivotal movement about an axis at right angles to the axis of the cylinder, the two axes being contained by the said plane.
5. A press as claimed in any one of claims 1 to 4, in which the split dies of each set are arranged in facing surfaces of the supports and each of the abutment means projects from a respective one of the surfaces.
6. A press as claimed in claim 5, in which the degree to which each abutment means projects from the surface is adjustable.
7. A press as claimed in claim 5 or claim 6, in which the abutment means comprises four members, two for each support, each member projecting from the surface of its support and being engageable with a respective abutment member on the other support.
8. A press as claimed in claim 7, in which the degree to which at least one of each pair of engageable abutment members projects from the surface of its support may be adjustable.
9. A press as claimed in claim 8, in which each of the said one abutment members is of elongate wedge-like form and is longitudinally moveable to increase or decrease the degree to which the member projects from the surface.
10. A hydraulic press for tubular work 'pieces and comprising two die supports, a hydraulic cylinder/ram assembly for effecting movement of one of the supports to wards the other support the said one support being attached to the cylinder/ram assembly for pivotal movement about an axis at right angles to the axis of the cylinder, and two sets of split dies carried by the supports one die set being positioned on one side of a plane containing the said axes and the other set being positioned on the other side of that plane, wherein two abutment means are.provided, one abutment means being arranged on that side of one of the die sets remote from the plane, and the other abutment means being arranged on that side of the other die set remote from the plane, the abutment means being equispaced from the plane and the die sets being equispaced from withe plane, and the abutment means being so arrange that when a workpiece is clamped in one die set the supports engage through the abutment means which is closer to the other die set.
11. A hyraulic press substantially as helre inbefore described, with reference to and as illustrated by the accompanying drawings.
12. A method of upsetting an end portion of a tubular workpiece using a press as claimed in any one of claims 1 to 11, the method comprising clamping the workpiece in one of the die sets, performing an upsetting operation on an end portion of the workpiece, removing the workpiece from the said one die set, clamping it in the other die set, and performing a further upsetting operation on the end portion of the workpiece.
13. A method of upsetting an end portion of a tubular workpiece, the method being 'substantially as hereinbefore described, with ,reference to and as illustrated by the accompanying dirawings.