Presses – Reciprocating press construction – Platen level compensating
Reexamination Certificate
2002-09-06
2003-12-02
Ostrager, Allen (Department: 3725)
Presses
Reciprocating press construction
Platen level compensating
C100S046000
Reexamination Certificate
active
06655267
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a slide inclination correcting method and a slide inclination correcting apparatus in press machinery for correcting an inclination of a slide caused by an eccentric load that acts thereon in a press machine while the press machine is in the process of forming, especially a large work piece or a plurality of work pieces.
BACKGROUND ART
Many an existing press machine has a construction in which a slide is movable vertically up and down by a slide drive mechanism disposed in an upper area of the machine. The slide is used to carry on its lower surface a die (upper die) while another die (lower die) is mounted on a bed or bolster in the machine for forming a work piece between these dies.
Also, in a press machine that is relatively large in size and further in what is commonly called a transfer press, one such slide may often be used to form a plurality of work pieces simultaneously. In such cases, it has been experienced that different forming loads applied on the work pieces create an eccentric load acting on the slide.
The slide in a press machine is typically moved vertically up and down as guided on a slide gib laid on a slide body. An eccentric load if produced acting on the slide may cause the slide to be inclined. A deviation in position that will then result between the upper die attached to the slide and the lower die mounted on the bolster makes it impossible to perform forming with precision and also let the dies wear off quickly, thus reducing their life to a large extent.
Also, an inclination of the slide produces a localized rise in bearing pressure between the slide gib and the slide guided thereon, which disadvantageously causes these bearing surfaces to wear off soon or even the bearing members to seize up so that the press machine may become no longer operable.
In an attempt to obviate such disadvantages, there has been proposed an apparatus in the art that is designed to correct a slide inclination in a press machine, e. g., as disclosed in JP U S62-34998. This bulletin discloses a slide inclination correcting apparatus in a press machine, having a makeup in which a overload protector designed to protect the slide from an overload has a fluid chamber therein fed with pressure fluid if a slide inclination is detected.
The correcting apparatus disclosed in that bulletin which in correcting a slide inclination relies on feeding a pressure fluid into the overload protector upon detecting the slide inclination is found to leave itself to be desired, however, presenting several problems. Thus, a time consumed for a pressure to be raised in the overload protector until the inclined slide is properly leveled and a limited accuracy with which it is so raised cause the known apparatus to be of a relatively slow response and limited follow-up capability and hence to be poor in productivity and limited in the abilities to make an accurate correction and thus to form work pieces with precision.
DISCLOSURE OF THE INVENTION
With the view to circumventing the problems met in the prior art, it is an object of the present invention to provide a slide inclination correcting method and a slide inclination correcting apparatus in press machinery which method and apparatus make it possible to achieve forming with due precision without impairing the machine's productivity. The present invention in one aspect thereof resides in finding by measurement or computation for each of dies or die sets an eccentric load that is to develop in the slide in the process of forming a work piece to prepare a die based slide inclination correcting data for each of the dies or die sets; and on the basis of the die based slide inclination correcting data prepared, pre-imparting to the slide a compensatory amount of inclination which corresponds to a predicted amount of inclination caused the slide due to the eccentric load found.
Thus, in order to achieve the object mentioned above, there is provided in accordance with the present invention in a first form of implementation thereof a slide inclination correcting method in press machinery having a slide drive mechanism disposed in a top area of a press machine for driving a slide via a plurality of points to vertically move it up and down, thereby forming a work piece, characterized in that the method comprises the steps of finding by measurement or computation for each of dies or die sets an eccentric load that is to develop in the slide in the process of forming a work piece to prepare a die based slide inclination correcting data for each of the dies or die sets; and on the basis of the die based slide inclination correcting data prepared, pre-imparting to the slide a compensatory amount of inclination which corresponds to a predicted amount of inclination caused the slide due to the eccentric load found.
According to the method described above, an eccentric load that does develop in the course of forming a work piece to act on a slide does not causes the slide to be inclined owing to the fact that a compensatory amount of inclination formed on the basis of a die based slide inclination correcting data for each of dies or die sets is pre-imparted to the slide to counteract the eccentric load. The effects of the method include the ability to form work pieces with due precision without impairing their productivity. Also, causing no deviation in position between an upper and a lower die, the method ensures preventing them from soon wearing off and does practically increases the die life.
The method described may specifically include the steps of detecting an actual amount of inclination of the slide on the basis of which a compensatory amount of inclination may be applied to the slide with the slide leveled thereby so that the slide and the upper surface of a bed or bolster become parallel to each other.
This specific method that seeks to maintain parallelism between the lower surface of the slide and the upper surface of the bed or bolster permits forming with due precision while impairing in no way the productivity. Also, causing no deviation in position between the upper and lower dies, the method ensures preventing them from soon wearing off and does practically increases the die life.
The method described may specifically include the steps of detecting an actual amount of inclination of the slide in the process of forming a work piece, using the actual amount of inclination detected to form a compensatory amount of slide inclination which corresponds thereto; and correcting the die based slide inclination correcting data by feeding back to the die based slide inclination correcting data the compensatory amount of inclination formed.
This specific method that allows the die based slide inclination correcting data to be enhanced in accuracy each time forming is repeated permits the compensatory amount of slide inclination that counteracts the eccentric load to be pre-imparted in each subsequent forming process to the slide in accordance with the die based slide inclination correcting data with a progressively increasing accuracy.
In order to achieve the object mentioned above, the present invention also provides in a second form of implementation thereof a slide inclination correcting apparatus in press machinery having a slide drive mechanism disposed in a top area of a press machine for driving a slide via a plurality of points to vertically move it up and down, thereby forming a work piece, characterized in that the apparatus comprises: a die based slide inclination correcting data acquisition means for acquiring a die based slide inclination correcting data by finding by measurement or computation for each of dies or die sets an eccentric load that is to develop in the slide in the process of forming a work piece; a fluid chamber provided for each of said points; and a slide inclination correcting means for adjusting in quantity a fluid in the fluid chamber on the basis of the die based slide inclination correcting data acquired by the die based slide inclination correcting data acquisition
Honma Hiroaki
Mukai Yoshiro
Takano Katsuhiro
Armstrong Westerman & Hattori, LLP.
Komatsu Ltd.
Nguyen Jimmy
Ostrager Allen
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