US3358486A

US3358486A - Forging method and apparatus

Info

Publication number: US3358486A
Application number: US452536A
Authority: US
Inventors: Beard Jack Herbert
Original assignee: Davy Loewy Ltd
Current assignee: Davy Loewy Ltd
Priority date: 1964-05-06
Filing date: 1965-05-03
Publication date: 1967-12-19
Anticipated expiration: 1984-12-19
Also published as: GB1037114A; DE1527289C2; DE1527289B1

Description

2 Sheets-Sheet 1 J. H BEARD FORGING METHOD AND APPARATUS Dec. 19, 1967 Filed May 5, 1965 w 5 l||||| w m u m VA VA i n 6 c w c w 2 w my a m 6 J l T mwlllm M J I B $Mm WWW L m 4 0 a g Q x n ,y 7 m n a 55$ Z 6 Pill! llllllllllllllllllll IL I q F INVEUIOQ J'. H BEARD By 4 8, M3,. MAM-A x w-s ATTORNEYS Dec. 19, 1967 J. H. BEARD FORGING METHOD AND APPARATUS 2 Sheets-Sheet 2 Filed May 5, 1965 INVEMTOE J. H BEA JLIWL wunM-u 514,30;

ATTORNEY;

:means for deriving United States Patent ABSTRACT OF THE DISCLOSURE The invention provides a method of and a control system for operating a forging press having a fixed and a movable press tool in which during the penetration stroke of the press the workpiece is moved parallel to the moving tool at substantially half the speed thereof.

This invention relates to a method of and apparatus for forging and more particularly to controlling the workpiece during the penetration stroke of a press having one fixed tool and one moving tool.

In one aspect the invention provides a method of forging a workpiece between a'fixed and a movable press tool, in which during the penetration stroke of the press the workpiece is moved parallel to the moving tool at substantially half the speed thereof.

In another aspect the invention provides a control system for a press and manipulator, the press having one fixed and one movable tool and the manipulator having a piston and cylinder assembly Connected with the peel for raising and lowering the peel, which system comprises first and second signals at the start and end respectively of the penetration stroke, and hydraulic valve means responsive to the first and second signals to control the hydraulic flow to and from the piston cylinder assembly such that the peel and workpiece carride thereby are moved together in the direction of movement of the moving tool during the penetration stroke and after the penetration stroke are returned to their original position.

Preferably the control circuit is arranged to drive the peel towards the fixed tool at a speed equal to half the expected speed of penetration of the movable tool.

The control circuit may include a valve for connecting a pressurised hydraulic supply through an adjustable constant speed valve to one side of the piston of the peel 'hoistcylinder assembly so as to drive the workpiece torwardsthe fixed tool, and means for returning the fluid driven from the other side of the piston during the penetration stroke, to that other side after the penetration "stroke.

An embodiment of forging apparatus and control circuit therefor, in accordance with the invention, will now be described, by way of example only, with reference to the accompanying drawings of which:

FIGURE 1 is a control circuit for automatically controlling the lowering and raising of a manipulator peel during forging, and I FIGURE 2 is a side view of a manipulator.

Referring first to FIGURE 1, a cylinder and ram 11 form the peel hoist assembly of a manipulator, one example of which is shown in FIGURE 2. Movement of the ram 11 to the right, in the drawing, serves to hoist the peel, while movement of the ram to the left, in the drawing, serves to lower the peel.

A pump 12 driven by motor 13 and having a safety valve 14 provides a pressurised hydraulic supply. The output of the pump is connected to the inlets 15a, 16a of

control valves

15, 16 respectively. Connection 15b of valve 15 is connected to one side of a piston type ac- 3,358,486 Patented Dec. 19, 1967 cnmulator 17, the other side of which connection 16b of valve 16 are connected through a counterbalance valve 18 to the head side of the hoist cylinder 10. The annular side of the hoist cylinder is connected to connection 160 of valve 16, through an adjustable pressure com pensated speed control valve 20 to the connection of valve 15. The valve 15, accumulator 17 and valve 20 are efiectively in parallel with the valve 16, and the inlets 15a, 16a are connected on line 20 to further control valves. The solenoids 22 of the valve 16 are intended to be operated manually, so that the operator may raise or lower the peel at any desired time independently of the movement of the press. When neither of solenoids 22 is energised, valve 16 will automatically be maintained in its neutral position permitting no flow through itself. Valve 15 is provided automatically to supply pressurised fluid to the appropriate side of the hoist cylinder during the penetration and return strokes of the press. Energisation of solenoid 23 acts on valve 15 to connect connections 15a and 150, and to connect connection 15b to an unpressurised tank. Energisation of solenoid 24 is adapted to act on valve 15 to connect connection 15a with connection 15b and to connect connection 150 to the unpressurised tank. The forging press is shown diagrammatically at 26 and has a moving tool 27 secured to cross head 28 slidable vertically on columns 30, and a fixed tool 31 secured to the press base 32. The crosshead is reciprocated by means of an acting piston and cylinder assembly 33 and lifting piston and cylinder assemblies (not shown) supplied from a pressurised source 34 controlled by the press position control 35 which may be of any known form such for example as that described in British Patent No. 874,908. The position of the moving tool may be measured by measuring means 35 connected between the moving crosshead 28 and the press base or other known means. In operation, the moving tool is'moved downwards until it contacts the workpiece at which point the pressure in the cylinder 33 rises; this pressure rise is measured by a pressure switch, of any known form e.g. a J. Langham Thompson type B.P.I. pressure transducer, which switch gives a signal passed on line 37 to energise solenoid 23. At the end of the penetration stroke, which may be determined either by the press positional control 35, in known manner, or by the pressure in cylinder 33 reaching predetermined maximum again indicated by pressure switch 36, the upper tool 27 is raised and the press positional control gives a control signal on line 38 which energises solenoid 24. Before a press stroke, while the moving tool is in its .upper position, the workpiece will be held in the manipulator peel on or just above the fixed tool 31 and valve 15 is in its neutral position. The upper tool is moved downwards until it contacts the workpiece and the pressure rises at the beginning of the penetration stroke, at which point the pressure switch 36 emits a signal which operates the solenoid 23 to direct pump pressure to the annular side of the hoist cylinder 10 through the pressure compensated speed control valve 21 which has been previously adjusted to cause the peel to be lowered at half the penetration velocity of the moving tool. Oil from the head side of the hoist cylinder passes through the counterbalance valve 18, to the piston accumulator 17. The piston of the accumulator rises against the load of its light spring, oil from the spring loaded side of the piston being permitted to escape to an atmospheric tank via valve 15.

When the pressure is reversed, either by the press positional control gear or on attainment of maximum pressure, the control signal causing the press reversal also operates the solenoid 24 to direct oil from the pump to the spring loaded side of the piston accumulator 17. The oil which was expelled from the head side of the hoist piston during the automatic lowering of the peel is now 'of the peel while the press load peel in the manner described in forced back to raise the peel to its original height before the penetration'stroke. Oil from the annular side of the hoist piston flows via the non-return valve incorporated in valve 20 and via valve 15 to atmospheric tank.

The

solenoids

23 and 24 are de-energised when the press positional control gear signals the end of the press return stroke.

It will be appreciated that there will be some lowering is being built up, that is, when the oil is being compressed and there is little penetration of the workpiece. This early lowering of the peel will serve to remove the strain in the peel shaft and its support induced by the weight to the workpiece and the taking up of the initial clearance between the workpiece and the bottom tool.

FIGURE 2 shows one example of manipulator which may be controlled in accordance with the invention. The

manipulator comprises a carriage structure supported on wheels 41 for movement towards or away from the press along a fixed track 42, and a drive motor 43. The forward end 44 of the peel projects from the carriage to carry a workpiece in conventional manner the peel being supported at its forward end in a block 45 surrounding the peel and housing a sprocket mounted in and keyed to the US. Patent No. 2,864,- 271. A depending loop of an endless chain 46 engages the sprocket within the block 45 while the upwardlyextending reaches of the chain pass over a pair of pulleys 47 and the horizontal reaches of the chain pass round a sprocket wheel 48 mounted on a slidable platform 5%. The platform 50 is slidable horizontally on the carriage support 40 by operation of a double-aeting piston and cylinder assembly 51, forward movement of the carriage 50 and thus sprocket wheel 48 serving to lower the forward end of the peel and rearward movement of carriage 59 serving to raise the forward end of the peel. The rear end 52 of the peel is rotatably carried by a ball end 49 mounted between a pair of crank plates 54-, only one of which is seen in the drawing, the crank plates being rotatably mounted on trunnions 53 on the support car riage. The rear end of the piston cylinder assembly 51 is also connected at 56 with the crank plates 54. The peel hoist

piston cylinder assembly

10, 11 is pivotally mounted at 57 on the manipulator carriage 4B is such that extension of the cylinder assembly 16), 11 pivots the crank plates 54 anticlockwise about the trumiions 53 serving to raise the rear end of the peel and at the same time to withdraw the piston cylinder'assembly 51 and thereby the platform 50 rearwardly so that the forward end of the peel is raised by the same amount; similarly when the ram 11 is withdrawn the crank plates are pivoted clockwise about trunnions 53 which lowers the forward end of the peel and pushes piston cylinder assembly 51 forward, pushing platform 51 and sprocket wheel 48 forward and lowering the forward end of the peel by the same amount as the rearward end of the peel; by this arrangement operation of the hoist piston cylinder assembly always moves the peel in a parallel manner.

What is claimed is:

1. A method of forging a workpiece comprising the steps of placing a workpiece between a fixed and a movable press tool, and during the penetration stroke of the press moving the workpiece parallel to the moving tool at substantially half the speed thereof.

2. A method according to claim 1 in which the workpiece is carried by a manipulator peel and in which the workpiece is moved during the penetration stroke by hy- 4 draulically driving the peel in the direction of the moving tool.

3. A method accordin of restoring the peel to its position before the penetration stroke after that stroke is completed.

4. A control system for a press and manipulator, the press having one fixed and one movable tool and the manipulator having a piston and cylinder assembly connected with the peel for raising and lowering the peel, which system comprises means for deriving first and second signals at the start and end respectively of the penetration stroke and hydraulic valve means responsive to the first and second signals to control the hydraulic flow to and from the piston and cylinder assembly such that the peel and workpiece carried thereby are moved together in the direction of movement of the moving tool during the penetration stroke and after the penetration stroke are returned to their original position.

5. A control system according to claim 4 arranged to move the workpiece and peel at substantially half the speed of the moving tool during the penetration stroke.

s. A control system for a press and manipulator, the press having one fixed and one movable tool, and the manipulator having a peel carrying a workpiece, the system comprising means for deriving a first signalat the commencement of the pentration stroke, means for deriving a second signal at the end of the penetration stroke, and a hydraulic control circuit responsive to the first and second signals to drive the peel in the direction of movement of the movable tool towards the fixed tool at a predetermined constant speed during the penetration stroke and to return the peel to its original position after the penetration stroke.

'7. A control system according to claim 7 in which the predetermined constant speed is substantially half the speed of movement of the movable tool during a penetration stroke.

8. A control system according to claim 6 including an adjustable constant speed valve for determining the predetermined constant speed.

9. A control system according to claim 8 including a peel hoist cylinder assembly having a piston and including a control valve operative by the first signal to conmeet a pressurised supply through the adjustable constant speed valve to one side of the piston of the peel hoist cylinder assembly so as to drive the peel parallel to the movable tool.

10. A control system according to claim 9 including means responsive to the second signal for returning the fluid driven from the other side of the piston of the peel hoist cylinder assembly during the penetration stroke to that other side after the penetration stroke.

11. A control system according to claim 10 including a spring loaded piston type accumulator connected to the other side of 12. A control system according to claim 6 in'which the means for deriving the first signal includes a pressure switch responsive to the rise in hydraulic pressure in the movable tool drive when that tool contacts a workpiece.

v to claim 2 including the step References Cited UNITED STATES PATENTS CHARLES W. LANHAM, Prim ry Examiner.

G. P. CROSBY, Assistant Examiner.

the piston of the peel hoist cylinder assembly

Claims

1. A METHOD OF FORGING A WORKPIECE COMPRISING THE STEPS OF PLACING A WORKPIECE BETWEEN A FIXED AND A MOVABLE PRESS TOOL, AND DURING THE PENETRATION STROKE OF THE PRESS MOVING THE WORKPIECE PARALLEL TO THE MOVINGG TOOL AT SUBSTANTIALLY HALF THE SPEED THEREOF.