Forging machine

Abstract

A forging machine with one or more hammers, comprising, for each hammer, an eccentric shaft (1) adapted to rotate about a first axis; a connecting rod (2), adapted to be actuated by the eccentric shaft operating as crank; a guiding frame (10); wherein the hammer is adapted to perform an alternating working movement within said guiding frame along a second axis perpendicular to the first axis; wherein the hammer comprises a hydraulic cylinder (8) provided with a hollow body (5), to which a forging member (15) is externally fixed, and with a piston (3) at least partially inserted within said hollow body and removably coupled to the connecting rod; wherein a first hydraulic chamber (6), arranged between piston and hollow body, allows to move the hollow body away from and/or towards said piston; wherein uncoupling means are provided for uncoupling the piston from the connecting rod.

Claims

1. A forging machine with one or more hammers, comprising for each hammer: an eccentric shaft, adapted to rotate about a first axis, a connecting rod, adapted to be actuated by said eccentric shaft operating as crank, and a guiding frame, wherein each hammer of said one or more hammers is adapted to perform an alternating working movement within said guiding frame along a second axis perpendicular to the first axis, wherein each hammer comprises a hydraulic cylinder provided with a hollow body, to which a forging member is externally fixed, and a piston at least partially inserted within said hollow body and removably coupled to the connecting rod, wherein a first hydraulic chamber, arranged between the piston and the hollow body, allows to move the hollow body away from and/or towards said piston, wherein uncoupling means are provided for uncoupling the piston from the connecting rod, whereby after uncoupling each hammer can be actuated hydraulically in alternating manner by means of the first hydraulic chamber, while when the piston is coupled to the connecting rod each hammer can be actuated mechanically in alternating manner by means of the eccentric shaft-connecting rod assembly and the first hydraulic chamber allows to adjust an average working position of each hammer along the second axis.

2. The forging machine according to claim 1, wherein said uncoupling means comprise a wedge arranged in a cavity provided between the eccentric shaft and the piston, said wedge being controlled by an actuator whereby when the wedge is in a first operating position a contact is provided between the wedge and the piston and a clearance is provided between the piston and the connecting rod, while when the wedge is in a second operating position a contact is provided between the piston and the connecting rod and a clearance is provided between the wedge and the piston.

3. The forging machine according to claim 2, wherein the wedge and the actuator are connected to a frame of the forging machine.

4. The forging machine according to claim 2, wherein a second hydraulic chamber is provided, configured to maintain a constant contact between the piston and the wedge when the wedge is in said first operating position, and configured to maintain a constant contact between the piston and the connecting rod when the wedge is in said second operating position.

5. The forging machine according to claim 4, wherein said second hydraulic chamber has an annular shape and is provided between the guiding frame and the hollow body.

6. The forging machine according to claim 1, wherein the first hydraulic chamber is provided with a maximum pressure valve, suitable to be actuated in case of overload when each hammer is mechanically actuated.

7. The forging machine according to claim 1, wherein the first hydraulic chamber is provided with a servo valve.

8. The forging machine according to claim 1, wherein a low friction member is provided between the piston and the connecting rod.

9. The forging machine according to claim 1, wherein a bearing is provided between the eccentric shaft and the connecting rod.

10. The forging machine according to claim 1, wherein said uncoupling means comprise a hydraulic slewing ring or electromechanical jacks coaxial with each hammer, or connecting rod disengagement members adapted to move the connecting rod to an off-axis position with respect to the second axis, or the connecting rod itself, the latter being of variable length type.

11. The forging machine according to claim 1, wherein there are provided a plurality of hammers of said one or more hammers moveable radially with respect to a longitudinal advancement axis of a product to be machined, and wherein a kinematic chain is provided, connecting the eccentric shafts of each hammer of the plurality of hammers, suitable to synchronize working strokes of the plurality of hammers.

12. A switching method for a forging machine, according to claim 1, for switching the forging machine from operating as swaging machine to operating as forging press, the method comprising the following steps of: a) providing the piston and the connecting rod in reciprocal contact so that each hammer is mechanically actuated in alternating manner by means of the eccentric shaft connecting rod assembly, with the first hydraulic chamber which allows to adjust only the average working position of each hammer along the second axis, the forging machine working as swaging machine; b) uncoupling the piston from the connecting rod by means of the uncoupling means so that each hammer can be actuated hydraulically in alternating manner, alternating an input and an output of liquid from the first hydraulic chamber, the forging machine working as a forging press.

13. The switching method according to claim 12, wherein in step a) the wedge is in said second operating position; and wherein after step b) the wedge is in said first operating position.

14. A switching method for a forging machine according to claim 1, for switching the forging machine from operating as forging press to operating as swaging machine, the switching method comprising the steps of: a) providing the piston uncoupled from the connecting rod by means of the uncoupling means so that each hammer can be actuated hydraulically in alternating manner, alternating an input and an output of liquid from the first hydraulic chamber, the machine forging working as forging press; b) coupling the piston to the connecting rod so that each hammer is mechanically actuated in alternating manner by means of the eccentric shaft connecting rod assembly, with the first hydraulic chamber which allows to adjust only the average working position of each hammer along the second axis, the forging machine working as swaging machine.

15. The switching method according to claim 14, wherein in step a) the wedge is in said first operating position; and wherein after step b) the wedge is in said second operating position.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Further features and advantages of the invention will be more apparent in light of the detailed description of a preferred, but not exclusive, embodiment of a forging machine illustrated by way of non-limitative example, with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a first section view of part of a machine according to the invention in a first operating mode as swaging press;

(3) FIG. 2 shows a second section view of said machine according to the invention in a second operating mode as forging machine;

(4) FIG. 3 shows a third section view of said part of machine according to the invention in the first operating mode as swaging press, with hydraulic cylinder in extended operating position.

(5) The same reference numbers in the figures identify the same members or components.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

(6) The figures show a preferred embodiment of part of a radial forging machine with one or more hammers which, according to the invention, can operate as a swaging machine or as a traditional forging press.

(7) Operating as a swaging machine means an operation of the machine with short hammer working strokes, e.g. in the order of a value either lower than or equal to 80 mm, and high frequencies, e.g. in the order of 2-8 Hz.

(8) Operating as a traditional forging machine means an operation of the machine with longer working strokes of the hammers, e.g. in the order of a value either lower than or equal to 500 mm, low frequencies, e.g. in the order of a value lower than 3 Hz, and modular forging speed up to a value either lower than or equal to 500 mm/s.

(9) The machine object of the present invention comprises for each hammer: an eccentric shaft 1, adapted to rotate about a first axis X, a connecting rod 2, adapted to be actuated by said eccentric shaft 1 operating as crank, a guiding frame 10 for guiding the hammer in its alternating working movement.

(10) The eccentric shaft 1 is provided with an eccentric portion 1 with respect to first axis X to which the connecting rod 2 is hinged. A bearing 12, preferably but not necessarily a hydrodynamic (oil film) bearing, is provided between connecting rod 2 and eccentric portion 1.

(11) Each hammer, adapted to perform an alternating working movement within the respective guiding frame 10 along a second axis Y perpendicular to the first axis X, comprises a hydraulic cylinder 8.

(12) Such a hydraulic cylinder 8 is provided with a hollow body 5, distal with respect to the connecting rod 2, to which a forging member 15 is externally fixed, and with a piston 3, proximal to the connecting rod 2 and at least partially inserted in the hollow body 5. The forging member 15 is preferably always arranged outside the guiding frame 10. However, it cannot be excluded that the forging member 15 is, in a retracted position, at least partially inside the guiding frame 10. Advantageously, the piston 3 is coupled in removable manner to the connecting rod 2 (FIGS. 1 and 2).

(13) A low friction member 13 is generally provided, arranged between the piston 3 and the connecting rod 2, integrally fixed to the piston 3 and preferably housed in a cavity of the piston 3 itself.

(14) The hydraulic cylinder 8 also comprises a hydraulic chamber 6, arranged between piston 3 and hollow body 5, which by introducing a liquid inside, e.g. hydraulic oil, allows to move the hollow body 5, and thus the forging member 15, away from the piston 3. Instead, the hollow body 5 can be moved towards to the piston 3 by letting liquid out from the hydraulic chamber 6. The inlet and outlet channels of the hydraulic oil connected to the hydraulic chamber 6, in common in the hydraulic cylinders, are not shown in the figures.

(15) Advantageously, uncoupling means are provided for uncoupling the piston 3 from the connecting rod 2.

(16) In a preferred variant, such uncoupling means comprise an actuator 18 which actuates a wedge 7, arranged in a cavity 20 of the structure of the machine provided between eccentric shaft 1 and piston 3 and which can move within said cavity, so that when the wedge 7 is in a first operating position, or first end position (FIG. 2), a contact is provided between wedge 7 and piston 3 and a clearance is provided between piston 3 and connecting rod 2, while when the wedge 7 is in a second operating position, or second end position (FIG. 1), a contact is provided between piston 3 and connecting rod 2 and a clearance is provided between wedge 7 and piston 3.

(17) The actuator 18 can be a hydraulic, pneumatic or mechanical jack, either automatically or manually actuated. The actuator 18 is fixed to a frame or main casing of the machine. The wedge 7 advantageously has a central hole 21 crossed by the end of the connecting rod 2 proximal to the piston 3.

(18) In other variants, the uncoupling means can comprise, for example, a hydraulic slewing ring, electromechanical jacks coaxial with the hammer, disengagement means of the connecting rod with displacement of the connecting rod in rotated position off axis with respect to axis Y, the connecting rod itself but of the variable length type (mechanical or hydraulic).

(19) In the first operating position (FIG. 2), i.e. after the uncoupling between piston 3 and connecting rod 2, the hammer can be actuated only hydraulically, in alternating manner, by means of the first hydraulic chamber 6. The machine can be made to work with long working strokes, and thus operating in forging press mode by moving the hollow body 5, and thus the forging member 15, alternatively away from or towards the piston 3 as desired, by either filling or emptying the hydraulic chamber 6. In this operating mode, it is further avoided that, during operation, the forging load is discharged onto the connecting rod 2, and thus onto the bearing 12 which is not rotating, because the thrust force on the piston 3 is discharged onto the main frame of the machine by means of the wedge 7 itself.

(20) In the second operating position (FIG. 1), i.e. when piston 3 and connecting rod 2 are coupled, the hammer can be actuated mechanically in alternating manner by means of the eccentric shaft 1-connecting rod 2 assembly. In this case, the machine may work as a swaging machine, with short hammer working strokes and high oscillating frequencies. The hydraulic chamber 6 allows only to adjust the average working position of the hammer along the second axis Y by adjusting the amount of liquid therein. By virtue of the presence of a maximum pressure valve (not shown), associated to the hydraulic chamber 6, it is possible to prevent discharging the overloads on the connecting rod 2 and, thus, on the bearing 12 also in this operating mode as a swaging machine.

(21) In a variant of the invention, the liquid can let in and out of the hydraulic chamber 6 by means of a servo valve so as to adjust the average working position of the hammer between one hammering strike and the other rapidly.

(22) A second hydraulic chamber 4, of annular shape, is further provided between the guiding frame 10 and the hollow body 5 of the cylinder 8. This second hydraulic chamber 4 is used to guarantee the constant contact between piston 3 and wedge 7 when the wedge is in said first operating position. In particular, this contact is guaranteed by the hydraulic pressure present in the annular chamber 4, which behaves as a hydraulic compensation spring.

(23) In a variant of the invention, said first operating condition occurs when the connecting rod 2 and the eccentric portion 1 of the shaft 1 are in high position, with reference to the figures.

(24) When instead the wedge 7 is in the second operating position, the second hydraulic chamber 4 is used to guarantee the constant contact between piston 3 and connecting rod 2. The shortening of the cylinder 8 is guaranteed by the hydraulic pressure in the annular hydraulic chamber 4 which behaves as a hydraulic compensation spring.

(25) The forging machine of the invention can be of the type with only one hammer or with two or more hammers, e.g. four hammers. In case of multiple hammers, the latter move radially with respect to the longitudinal advancement axis of the product to be processed. A kinematic chain connecting the eccentric shafts 1 of the single hammers is provided to synchronize the working strokes of all hammers of the same machine in swaging machine mode.

(26) With the machine of the invention it is thus possible to switch from operation as a swaging machine to operation as a forging press. The operating method change consists of the following steps: a) providing the piston 3 and the connecting rod 2 in reciprocal contact so that the hammer is mechanically actuated in alternating manner by means of the eccentric shaft 1-connecting rod 2 assembly, with the first hydraulic chamber 6 which allows to adjust only the average working position of the hammer along the second axis Y, the machine being able to work as a swaging machine; b) uncoupling the piston 3 from the connecting rod 2 by means of the uncoupling means so that the hammer can be actuated hydraulically in alternating manner, alternating an input and an output of liquid from the first hydraulic chamber 6, the machine working as a forging press.

(27) In step a) the wedge 7 is in said second operating position, with a clearance between wedge 7 and piston 3. After step b) the wedge 7 is in said first operating position with a contact provided between wedge 7 and piston 3.

(28) Conversely, the switch from operating as a forging press to operating as a swaging machine occurs by means of the following steps; c) providing the wedge 7 in the first operating position, with piston 3 and wedge 7 in contact with each other and with piston 3 and connecting rod 2 uncoupled from each other, so that the hammer can be actuated hydraulically in alternating manner, alternating an input and an output of liquid from the first hydraulic chamber 6, the machine being able to work as a forging press; d) coupling the piston 3 to the connecting rod 2 by switching the wedge 7 from said first operating position to the second operating position, in which a clearance is provided between piston 3 and wedge 7, so that the hammer is actuated in alternating manner by means of the eccentric shaft 1-connecting rod 2 assembly, with the first hydraulic chamber 6 which allows to adjust only the average working position of hammer along the second axis Y, the machine being able to work as a swaging machine.