Forging Machine

Abstract

A so-called quick forging machine for forging elongated half-finished products by means of four peripherally distributed forging units incorporates cyclically driven forging arms which are selectively: either retained fixedly against a stationary stop for operation in one mode or are freely pivotal about an axis for operation in a second mode. The stroke of the main operating piston is transmitted to the workpiece through hydraulic thrust-transmitting means which yield during linear operation in the first mode and transmit the thrust in the second mode. Elongated forged products of circular cross section as well as square or rectangular members having rounded or sharp edges can thereby be produced on the same machine. The invention relates to a forging machine with four forging rams surrounding the workpiece to be shaped, for reducing the cross-section of the material by compression action, each of which is provided with its own driving unit with such arrangements each unit may comprise an angle member adapted to pivot about an axis parallel to the forging axis and one arm thereof forms a guide for the ram. Forging machines of this construction are utilised for the production of elongated metal workpieces of square, rectangular or circular cross-section. For this purpose pivoted guide systems and linear guide systems may be used and either the pivoted guide or the linear guide is fitted into the machine. In the interests of operational rationalisation by eliminating conversion times and so on it would be desirable if the advantages of both systems could be made use of in one machine. This technological distinction may arise in reference to a universal forging programme due for example to part-finished shapes of square or circular cross-section with the further condition of part-finished shapes with rounded or sharp edges. The invention is directed to the problem of securing the advantages of fitted pivoted or linear guides, previously always installed separately, in a convenient functional construction of a forging machine. This advantage is obtained according to the invention by the fact that pivoted and linear guides are fitted in each unit of the machine and are operable alternatively. In order to attain this object constructionally the forging arm is adapted to be retained by means of a pull-back cylinder and in the guide part of the forging arm there is arranged a plunger operable in step with the movements of an operating piston and movable laterally against a hydraulic thrust piston. In a convenient arrangement of the invention the pistons of the hydraulic thrust piston rests against a flange-like head part of the plunger carrying the forging ram. In order to be able to exert its function as a linear guide the angle member of the forging arm is provided with a lateral lug which is engageable with a stop of adjustable length.

Description

One constructional example of the invention is shown by way of example in the drawing and is described further below, wherein:

FIG. 1 shows a forging machine with four rams and associated combined pivoted and linear guide means,

FIG. 2 shows a section through one of the forging arms with the angle member, the main cylinder, the thrust transmitting cylinder and the pull back cylinder.

The casing 1 of the forging machine incorporates four forging units 2, 3, 4 and 5. A main operating piston 10 is provided in each of the four hydraulically operated main cylinders 6, 7, 8 and 9, each being functionally connected through a thrust pin 11 to a plunger 12. The plunger 12 carries the forging ram 18 and is displaceably arranged in one limb of the forging arm 14 which is in the form of an angle member 13 which is rotatably supported on a bearing pin 15. At the end of the plunger facing the workpiece 17 interchangeable rams or hammers 18 are provided. The flanged head 12a of the plunger 12 serves as a counter member for hydraulically operated thrust pistons 19, 20.

A piston rod 21 of a pull-back cylinder 22 acts on the angle member 13 at a point 16 and the angle member 13 has a lug 23 which engages an adjustable stop 24.

In operation for forging circular or square cross-sections with rounded edges the rams or hammers 18 move around the pivots 15 in step with the driving crank mechanism. The movement of the rams towards the centre of the workpiece is effected by the arms 14. The radially directed movement of the main piston 10 is linear while the movement of the plunger 12 is on an arc the radius of which corresponds to the length of the lever arm 14. The thrust pin 11 is provided for compensating the slight transverse movement between the piston 10 and the end of the plunger 12. Other devices having the same function can of course be incorporated.

To obtain rectangular cross-sections having different aspect ratios the bearing pins 15 of the arms 14 must first be adjusted transversely to the forging axis in a manner not shown. Sharp edged square or rectangular cross-sections cannot be produced at all or only with difficulty. With the new system it is possible to produce such cross-sections with sharp edges in the same machine if each of the arms 14 is held stationary and the plunger 12 moves in the angle member 13 in step with the crank drive mechanism.

In order to obtain the relative movement between the engaging faces of the parts 12 and 13 with simultaneous fixation of the arm 14 the pressure in the pull-back cylinder 22 must first be increased until it exceeds the pressure in the cylinders of the thrust pistons 19 and 20. These hydraulic features act in two ways; the lever 14 comes into positive engagement with the stop 24 while the plunger 12 moves in an oscillating manner in the linear guide 13, in rhythm with the main piston 10, acting through the thrust pin 11 against the pistons 19, 20 acting in the reverse direction.

On transition to the second method of forging the angle member is no longer securely held against, the stop 24 by reducing the pressure in the pull-back cylinder 22 while at the same time the pressure in the cylinders of the thrust pistons 19, 20 becomes preponderant whereby the relative movement between the plunger 12 and the linear guide 13 is momentarily eliminated. At the opposite end of the plunger 12 the lugs 12b come into firm engagement at the same time with the annular edge of the part 13. Thereafter the arm 14 can move freely about the pivot 15; that is to say that reciprocation of the main piston 10 and of the pull-back cylinder 22 is now possible.

A particular operational advantage is the relatively rapid transition from one method of forging to another. As a practical consequence one forging machine can be saved assuming a forging programme of normal range and variety. Besides the substantial simplification the halving of the investment in machinery represents a considerable saving in cost.

Claims

What I claim is:

1. In a forging machine having four forging units disposed about the work piece to be deformed, each unit comprising a hammer rectilinearly slidable in an arm which in turn is pivotally mounted about an axis parallel to but laterally displaced from the axis of the work piece, and drive means for driving said hammer toward said workpiece, the improvement comprising:

selectively operable means for locking said hammers against sliding movement in said arms and for selectively locking said arms against pivotal movement about said parallel axes whereby said drive means may be made to swing said hammers and arms as a unit about said parallel axes or slidably move said hammers in said arms while said arms are held against movement.

2. A machine as defined in claim 1 wherein said drive means comprise hydraulic actuators and wherein said means for locking said arms comprise hydraulic means for holding said arms against fixed stops.

3. A machine as defined in claim 2 wherein said fixed stops are adjustable.

4. A machine as defined in claim 2 wherein said means for locking said hammers in said arms comprises hydraulic holding means carried by said arms and operable to hold said hammers against sliding movement therein.

5. A machine as defined in claim 4 wherein said hydraulic holding means comprise movable pistons on said arms, engageable with flange-like head portions on said hammers to urge said hammers away from said work piece and wherein said hammers and arms are provided with cooperating stop means to limit movement of said hammers by said movable pistons.

6. A machine as defined in claim 4 wherein said hydraulic actuators of said drive means include drive pistons for driving said hammers toward said work piece, said movable pistons being operable to move said hammers and drive pistons away from said work piece when said arms are locked against pivotal movement.