Metal deforming – By three or more coacting relatively movable tools – With means to actuate tools in sequence
Patent
1996-08-26
1998-03-31
Crane, Daniel C.
Metal deforming
By three or more coacting relatively movable tools
With means to actuate tools in sequence
7245302, B21J 714, B21J 728
Patent
active
057325880
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/EP95/04226, filed Oct. 27, 1997.
FIELD OF THE INVENTION
The invention relates generally to a double press for forging round or edged bar-shaped workpieces using two pairs of forging dies offset at 90.degree. angles from one another and working against each other where said forging dies may be driven hydraulically by two pump assemblies.
BACKGROUND
The basic design of each double press unit consists of two cylinder-piston units working against each other and forming the workpiece without moving its center axis, as is, for instance, described in the German disclosure paper 2 221 341, Schmoll. Two such presses are arranged one after another in the longitudinal axis of the workpiece, offset at a 90 degree angle from one another, such that they can form bar-shaped workpieces perpendicular to the longitudinal axis in two planes.
Simultaneous forming of bar-shaped material in two planes perpendicular to the longitudinal axis of the workpiece with so-called forging machines is generally known. However, with the exception of the machine described in my DE 38 00 220 C1, all such machines use four dies in one plane. Due to their design, they are limited in die width or in stroke length and cannot operate with metallurgically advantageous deformation values.
Although the machine according to my DE 38 00 220 C1 is capable of operating with two pairs of dies offset in the longitudinal axis of the die, their working cylinders are still in one plane, and thus would be exposed to strong eccentric forces if the die widths required for freeforming conditions were used.
A forging machine where synchronization of the cylinder-piston units working against each other is accomplished by articulated levers connecting the forging dies via a gliding piece that glides in a guide perpendicular to the working axis is known from DE 29 51 587, Betz. The gliding piece is impacted by a pull-back cylinder, which causes the forging dies to be pulled back via the articulated pieces. The function of pulling back the forging dies can be accomplished by an additional pair of cylinder-piston units working against each other that is located perpendicular to the first pair in the same plane. This ensures the synchronized alternating drive of the two piston pairs.
A significant disadvantage of the forging machine mentioned is that mechanical synchronization does not allow for stroke variations of the forging dies. However, adjusting the stroke to the decreasing material thickness would lead to shorter set times of the pistons resulting in highly desirable faster forging and in reduced energy consumption. In addition, controlling the cylinder-piston unit with valves in the main lines limits the stroke frequency.
An additional disadvantage of mechanical synchronization is the enormous wear of the gliding piece guides or forging dies caused by the forces acting on the articulated levers, thus straining the guides with a component vertical to the working axis. Arranging two freeform presses in sequence is also not practical with the technical solution described.
When controlled by hydraulic valves, a big portion of the drive energy of such forging machines is lost by compressing the large amount of pressure medium that cannot be used effectively but heats up pressure medium and machine requiring cooling.
SUMMARY OF THE INVENTION
It is the objective of this invention to provide a double press that eliminates the design disadvantages of the forging machine according to DE 38 00 220 and that is less expensive to manufacture. In addition, it should be facilitated to operate with adjustable stroke and at high stroke frequency the two pairs of cylinder piston units (working against each other) of a forging machine, particularly the double press subject to the invention. It is also advantageous to use the power of the driving pump assemblies more efficiently and ensure precise synchronization of the forging dies with simple means.
This task is accomplished according to the invention by the two pairs of forging dies bei
REFERENCES:
patent: 3460370 (1969-08-01), Kralowetz
patent: 3645126 (1972-02-01), Kralowetz et al.
patent: 3681966 (1972-08-01), Kralowetz
patent: 3817070 (1974-06-01), Ribback
patent: 3841125 (1974-10-01), Guse
patent: 3916667 (1975-11-01), Paknke
patent: 4941342 (1990-07-01), Herndl
Crane Daniel C.
Pahnke Engineering GmbH & Co. K.G.
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