IMPROVED HORIZONTAL FORGING PRESS

The present invention relates to an improved horizontal forging press Horizontal forging presses are known. For these, a metal bar is heated, generally by induction, and then cut into workpieces of length suitable for the article to be forged, these workpieces being subjected to the sequential action of several dies, in each of which each workpiece undergoes partial deformation, before being removed and transferred to the next die, in which the deformation action is continued until the final configuration is achieved in the last die. The completely forged article is extracted from this latter, to be fed to subsequent machining.

To perform their operating cycle, known horizontal forging presses are constructed in mutually coordinated parts, which perform the following functions: - feeding the metal bar through a heating furnace,

- cutting the heated bar into workpieces of predetermined length,

- transferring each workpiece from the bar feed line to the first die,

- operating the ram to forge the workpiece in the first die,

- expelling the workpiece forged by the first ram and transferring it into the second die,

- operating the ram to continue forging of the workpiece in the second die, and so on until the article has been finally forged in the last die, which is generally the fourth.

In known horizontal forging presses, the ram acts on the various dies and is driven such that the workpiece positioned in each die undergoes the

required forging as a result of the rhythm set by the machine, before it is removed and advanced by one position, for transfer into the next die.

In addition to the ram, which is required to simultaneously deform all the workpieces in the respective dies, an energy quantity sufficient for this work has to be supplied, this energy varying according to the dimensions and configuration of the workpiece to be shaped, and the number of dies operated simultaneously. For this, a flywheel is associated with the ram of a traditional horizontal forging press, to store energy during the inactive period, and return it during forging. Another component of a traditional horizontal forging press is a transfer device, the function of which is to transfer each workpiece from the feed line to the first die, from each die to the next and from the last die to the exit line.

It will be apparent that a horizontal forging press requires the movement of a large number of parts, this movement having to be synchronized because the machine operates simultaneously on a different number of workpieces by means of a corresponding different number of components, for all these operations the various components having to be coordinated to execute the predetermined operative cycle. This synchronization is currently achieved by providing the machine with a single drive and deriving therefrom the various movements required to operate the individual components by means of shafts, couplings, cams transmissions, etc. This involves an extremely complex machine construction, high energy consumption, very large overall dimensions, costly maintenance and essentially a series of problems which substantially influence operating costs.

Moreover, as a horizontal forging press must be able to machine workpieces of different dimensions and shapes, requiring the machine to undergo adaptation at each working change, this adaptation requires high manual skill and a likewise high machine technical knowledge, together with lengthy operator experience. If the press, having been arranged to machine a certain type of workpiece and then been modified to machine a workpiece of different type, has then to be rearranged to machine the original workpiece, it must be again subjected to a whole series of adaptations, as if the workpiece to be machined were completely new rather than a workpiece which had already been machined on that press.

An object of the invention is to eliminate all these drawbacks by providing a horizontal forging press which compared with traditional presses is of simple construction, small overall size, simple maintenance and high flexibility, and which once set to machine workpieces of a certain type, can be immediately readapted to again machine such workpieces, even after losing the adjustments required for machining workpieces of different configurations. This and further objects which will be apparent from the ensuing description are attained, according to the invention, by an improved horizontal forging press as described in claim 1 . A preferred embodiment of the present invention is further clarified hereinafter with reference to the accompanying drawings, in which: Figure 1 is an overall schematic perspective view of a press according to the invention,

Figure 2 is a longitudinal section therethrough, Figure 3 is a side view of the feed block for the steel bar originating from the heating furnace,

Figure 4 is a front view thereof on the line IV-IV of Figure 3, Figure 5 is a perspective view of the bar cutting unit, Figure 6 is a section therethrough perpendicular to the bar axis, Figure 7 is a perspective view of the transfer unit associated with the press. As can be seen from the figures, the forging press of the invention, shown in overall view in Figure 1 , comprises essentially a machine body 2, which in the illustrated embodiment is formed from separate parts joined together by bolts or similar systems along mutually contacting toothed surfaces. The machine body comprises in traditional manner two shoulders 4, a base 6 and a striker portion 8.

The two shoulders 4 support a shaft 10 provided with a cam, on which a connecting rod 12 engages for reciprocatingly driving a ram 14 towards and away from the striking portion 8, to which a plurality of dies are applied, cooperating with an equal number of punches applied to the ram 14.

The camshaft 10 emerges from the two shoulders 4 of the machine body 2 via both ends, on which two flywheel-brake-clutch units are applied.

To one of the two shoulders 4 a unit 18 is applied for feeding the steel bar originating from a heating furnace (not shown), together with a bar cutting unit 22 applied downstream of this unit 18, with reference to the bar feed direction, indicated by the arrow 20 in Figure 1 .

Four dies 24 are applied to that side of the striking portion 8 facing the machine interior and, as stated, face four punches 26 applied to the ram 14.

A transfer unit 28 is applied to the machine body in a position in front of said dies 24, and hence interposed between these and the punches 26.

A group of four expulsion devices 30, one for each die 24, is also applied to the striking portion, on the outside of the machine.

The feed unit 18 comprises two pairs of superposed feed rollers 32 driven by an electric motor 34. The rollers 32 have a profile such as to embrace the steel bar, to cause it to advance towards the cutting unit 22.

This cutting unit 22 comprises within a box casing 36 a crankshaft 38 driven by a motor 40 and connected, via a connecting rod 42, to a slide 44 guided by said casing 36 and provided at its end with a knife 46.

The knife 46 in reality consists of a metal block comprising a central hole 48 for passage of the steel bar to be cut and driven with reciprocating movement between a position aligned with said bar and a position aligned with the first die 24.

Each expulsion device 30 comprises a body 50 for its fixing to the striking portion 8, a movable portion connected to the corresponding die 24 and a motor which drives said movable portion with axial movement between a position contained within the die and a position projecting from it.

The transfer unit 28 comprises a structure 54 for its fixing to the striking portion 8, and a bar 56 supporting four grippers 58.

Each gripper 58 is pivoted about its pin to the bar 56 and can swivel thereabout between two end positions under the control of a motor 78, via a connecting rod 76 and a bar 74.

Each gripper 58 also comprises a pair of jaws 60, 64, pivoted on respective pins and associated with an air spring 62, which tends to maintain them elastically in their closed configuration, and on a cam 66 which tends to open them under the control of a crank 82 driven by an electric motor 80 via a connecting rod-crank coupling 82.

In a different embodiment, not shown in the drawings, each gripper is associated with its own electric motor, to enable it to be operated independently of the other grippers.

The gripper carrier bar 56 is movable vertically to the structure 54 and is controlled in its movements by a motor 68 via a crankshaft 70 and a pair of connecting rods 72.

All the motors of the press according to the invention, i.e. the motors 34, 40, 52, 68, 78, 80 are preferably of direct drive type and are controlled by the machine operative unit. The press of the invention operates in the following manner:

The steel bar heated in the furnace is fed intermittently by the feed unit 18 in portions of predetermined length corresponding to the metal quantity required to produce a forged workpiece.

When the bar portion of predetermined length has been positioned on the knife 46, this is operated by the motor 38, which advances the knife and in addition to cutting the workpiece from the bar, it positions it in the first die 24.

The camshaft 10 is then rotated through one revolution in traditional manner, the ram 14 then being made to strike such that with the first punch it determines initial forging of the steel workpiece in the first die 24. After the ram 14 has terminated its return stroke and the die has been reopened, the expulsion device 30 is operated to discharge the forged workpiece from the die and position it between the open jaws 60, 64 of the first gripper, positioned in front of the die.

By synchronized coordinated movement of the transfer unit 28, this gripper 28, after gripping the workpiece, is raised and then swung to position

that workpiece in the second die 24, on which the ram 14 then acts to carry out the second forging step.

The cycle then proceeds until, on termination of the final forging step in the fourth die 24, the workpiece is withdrawn by the fourth gripper 58, to be transferred to discharge.

During the progressive forging of the workpiece in the four dies 28, other workpieces are subjected to different forging steps in the dies, such that during normal working the press works on four workpieces at a time, at each cycle a bar workpiece being inserted into the first die and a forged workpiece being extracted from the last die.

The press of the invention, and in particular the independent driving of the various parts, makes the press much more advantageous than traditional horizontal presses, and in particular:

- it enables the bar feed to be regulated easily and precisely on the basis of the dimensions of the workpiece to be cut from it,

- it enables the bar to be moved rearwards during the return of the cutting knife, so that the knife cutting edge does not slide on the bar, to not only substantially reduce knife wear but also reduces defects in the workpieces cut off, - it enables the bar to be fed and cut in accordance with requirements, and in particular either at each blow of the ram 14 or at every so many machine blows, in a totally flexible manner, depending on the shape of the workpiece and the machine load, to be able also to forge with one or more empty dies.

Moreover in the press of the invention, a workpiece to be forged does not have to be positioned in every die, hence enabling the kinetic energy transmitted to the ram 14 to be used to forge just one or more than one

workpiece, but less than the maximum number which could be forged simultaneously, in this manner utilizing the machine capacity to forge larger dimension workpieces not forgeable by a traditional machine of equivalent performance. More particularly, if the workpiece dimensions require it, the machine can be operated without a workpiece on each die, but instead leaving some dies free, to be able to utilize the kinetic energy transmitted to the ram only on a small number of dies, to hence be able to forge workpieces of greater dimensions, which cannot be achieved in traditional forging presses. Moreover, in order to achieve still greater operative flexibility, the forging press of the invention uses not just one flywheel but a pair of flywheels, with a double brake, double clutch and double drive, in order to be able to use one or both flywheels according to the kinetic energy required by the particular shape and/or size of the workpiece to be machined. This facility for using greater kinetic energy to deform the workpieces enables them to be heated to a lower temperature, and hence substantially reduce the energy consumption for this heating.

Finally, the use of independent motors for the different drives results in the elimination of the entire assembly of drives, transmissions, couplings etc. which in the past contributed to considerable operative complexity of the machine and a likewise considerable difficulty in adjusting and adapting the machine to the handling of different workpieces. In particular, if the machine had already been adapted to forge a certain type of workpiece, the relative data are memorized in the control unit and can be recalled, via software, to enable the machine to be immediately adapted to again forge the same workpiece.