Metal deforming – With means to drive tool – With means to permit tool positioning
Patent
1989-05-30
1991-02-26
Jones, David
Metal deforming
With means to drive tool
With means to permit tool positioning
72404, 72465, 100918, B21D 3700
Patent
active
049952552
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method of changing dies for a press machine such as a transfer press or the like having two or more slides arranged in a side-by-side relationship of which lower dead point in terms of a crank angle is different from each other.
BACKGROUND ART
As shown in FIG. 10, a hitherto known transfer press employable mainly for deep drawing operations is provided with a link driven type slide b adapted to be driven by a link mechanism on the upstream side as seen in the direction of transference of works (as represented by an arrow mark a) and an eccentric gear driven type slide (hereinafter referred to as an eccentric driven type slide) d adapted to be driven by an eccentric portion on the main shaft via a connecting rod on the downstream side.
With such conventional transfer press, a crank angle representative of the lower dead point of the link driven type slide b for deep drawing operation on the upstream side is deviated from a crank angle representative of the lower dead point of the eccentric driven type slide d by an angle in the range of 10.degree. to 20.degree.. For the reason, when the one slide has reached the lower dead point, the other slide has still a certain amount of gap between the upper die half and the lower die half.
In view of this fact, conventional die changing is achieved for two slides in such a manner that one of the dies is separately unclamped from the corresponding slide at the different time when the latter is lowered to its lower dead point. This leads to drawbacks that a long time is required for die changing and die changing operations are performed at a reduced efficiency.
The present invention has been made with the foregoing background in mind and its object resides in providing a method of changing dies for a press machine of the type including two or more slides of which lower dead point in terms of a crank angle is different from each other which assures that the dies on the slides can simultaneously be exchanged with another ones and a time required for die changing can be reduced substantially.
DISCLOSURE OF INVENTION
To accomplish the above object, the present invention provides a method of changing dies for a press machine of the type including two or more slides of which lower dead point in terms of a crank angle is different from each other, wherein elastic means is interposed between an upper die half and a lower die half for the respective slides and movement of the respective slides is simultaneously interrupted at a crank angle in the proximity of an intermediate angle between the plural lower dead points so that clamping of the upper die half to or unclamping of the same from the respective slides is achieved during the interruption of movement of the respective slides.
According to the present invention, when the respective slides are held immovable, the lower surfaces of the upper die halves come in contact with the upper surfaces of the lower die halves with elastic means interposed therebetween and the respective slides remain at the same height. Thus, when the respective upper die halves are unclamped from the respective slides as long as the aforementioned state is maintained, the upper die halves are placed on the lower die halves via the elastic means without an occurrence of falling-down of the upper die halves on the floor. Similarly, upper die halves on plural slides can simultaneously be unclamped from the latter, e.g., by displacing respective bolsters outside of the press line. Things are the same with a case where the upper die halves are clamped to the respective slides. Namely, when the respective slides reach the vicinity of the intermediate angle, their movement is interrupted so that the upper die halves can simultaneously be clamped to them.
Consequently, according to the present invention, die changing (die unclamping/die clamping) can simultaneously be achieved with the respective slides. This assures that a time required for die changing can substantially be reduced and a transfer pres
REFERENCES:
patent: 2781015 (1957-02-01), Dehn et al.
patent: 3233441 (1966-02-01), Dunlap
patent: 4601422 (1986-07-01), Dumargue et al.
patent: 4700624 (1987-10-01), Murphy
Jones David
Kabushiki Kaisha Komatsu Seisakusho
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