Metal deforming – By use of tool acting during relative rotation between tool... – Work-hammering tool
Reexamination Certificate
1999-12-07
2001-06-05
Larson, Lowell A. (Department: 3725)
Metal deforming
By use of tool acting during relative rotation between tool...
Work-hammering tool
C072S452600
Reexamination Certificate
active
06240759
ABSTRACT:
1. FIELD OF THE INVENTION
This invention relates to a forging machine comprising at least two forging punches acting against each other and longitudinally guided in a forging box, which each have separate mechanical lifting drives and preferably vertical position adjusting means.
2. DESCRIPTION OF THE PRIOR ART
In known forging machines, eccentric drives are mostly used as mechanical lifting drives, where the rotary movement of the eccentrics is converted into lifting movements of the forging punches due to a cooperation of sliding blocks rotatably mounted on the eccentrics and connecting rod heads of the forging punches accommodating the sliding blocks. The forging forces which occur during forging therefore apply a bending load onto the eccentric shafts via the forging punches, so that these eccenctric shafts must be dimensioned and supported accordingly, which involves an increased constructional effort. To adjust the vertical position of the forging punches, there must also be provided special adjustment housings for mounting the eccentric shafts, whereby the machine frame is weakened in its rigidity because of the required bearing lugs, and due to the displacement of the center of the eccentric shafts during the adjustment a suitable eccentric shaft drive compensating this offset is required. When the forging punches are composed of two parts screw-connected with each other for adjusting the vertical position, of which screw-connected parts the one is non-rotatably guided with respect to the forging box and the other is rotatably guided, and the rotatable part communicates with a rotary drive, so that because of the mutual screw connection of the parts a rotation of the rotatable part effects a change in length of the forging punch and thus an adjustment of the vertical position, the impairment of the load-bearing capacity of the punches must be taken into account in addition to the lifting movement of the punches, which requires a relative axial movability of the rotating part with respect to the rotary drive and likewise leads to a more complex construction.
SUMMARY OF THE INVENTION
It is therefore the object underlying the invention to create a forging machine as described above, which is characterized by its novel drive concept and the related high rigidity and simplified construction.
This object is solved by the invention in that the lifting drives are comprised of a wobble-plate drive including a wobble plate rotatably and drivably, but immovably mounted in the forging box about a wobble axis offset in parallel with respect to the respective forging punch axis and a pressure plate associated to the wobble plate and supported in the manner of a ball-and-socket joint on the end face of the associated forging punch facing the wobble plate, where preferably the forging punches can be pressurized via pressure springs in the sense of a frictional connection of wobble plates and pressure plates. By rotating the wobble plate, which is eccentric with respect to the forging punch axis, a lifting movement with a frequency corresponding to the rotational speed of the wobble plate is forced onto the forging punch in dependence on the inclination of the wobble plate and the eccentricity, which lifting movement serves the forming of the workpiece. The occurring forging forces are substantially directly transferred from the forging punch via the pressure plate to the wobble plate, which leads to pure pressure loads and involves an increased machine rigidity with simplified supporting conditions. There is a frictional cooperation between wobble plates and pressure plates, which is ensured by appropriate loads of the forging punches. There are expediently used pressure springs, for instance hydraulic cylinders connected to an accumulator, which urge the pressure plates and wobble plates against each other and prevent the same from being lifted off each other.
In accordance with a particularly advantageous aspect of the invention, a shaft stub of the wobble plate is rotatably, but axially immovably seated in a bearing sleeve axially movably supported in the machine box, so that a change in the vertical position is effected by a longitudinal adjustment of the bearing sleeve independent of the actual lifting movement of the forging punches, as by means of the change in the axial position of the wobble plates there are also adjusted the axial positions of the pressure plates and thus of the forging punches. The bearing sleeve in addition provides for a stable support of the drum plate, where here as well bending loads are largely avoided.
The bearing sleeve as such might axially adjustably be inserted in the machine box in any suitable way, where a screw drive is, however, particularly suited for longitudinal adjustment, and the external thread of the bearing sleeve engages in an adjusting nut rotatably, but axially immovably supported in the forging box, to which adjusting nut a rotary drive is associated. Rotating the adjusting nut effects a corresponding change in the axial position of the bearing sleeve due to its screw connection with the bearing sleeve, where the parts of the screw drive can take high loads and transfer the same to the forging box.
When the rotary drives each include a drive gear, which drive gears cooperate with a central wheel mounted at the forging box so as to be rotated about the axis of movement, a common adjustment of the vertical position of all forging punches can be achieved without major difficulties.
The wobble plate can be driven in various ways, and the wobble plate can for instance be driven via a toothed-belt drive and together with a peripheral gear rim forms the one crown gear thereof, which wobble plate drive can be accommodated in the forging box in a space-saving way and provides for the simple use of corresponding transmission ratios to achieve the desired rotational speed of the wobble plate.
To provide a common drive for all wobble plate drives, the wobble plates of all wobble plate drives can be driven via a common bevel gear transmission comprising a large bevel gear mounted on the forging box so as to be rotated and driven about the axis of movement and small bevel gears associated to the wobble plates, which leads to synchronous hammering movements in an economic way. The wobble plate drive as lifting drive is suited not only for forging machines with stationary forging box, but also for forging machines used as swaging machines, in which case the forging box is mounted in a machine frame so as to be rotated and driven about the axis of movement. Since the lifting drives and the vertical position adjusting means are disposed and supported at the forging box, their mode of function is not changed by the rotary support of the forging box, and the common adjustment of the vertical position and/or the common wobble plate drive are also maintained when the respective drive gears are part of planetary gear systems.
REFERENCES:
patent: 5315926 (1994-05-01), Kanamaru et al.
Collard & Roe P.C.
GFM Beteiligungs und Management GmbH & Co. KG
Larson Lowell A.
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