Cutting – With product handling means – Means to move – guide – or permit free fall or flight of product
Reexamination Certificate
1998-09-25
2001-06-05
Rachuba, M. (Department: 3724)
Cutting
With product handling means
Means to move, guide, or permit free fall or flight of product
C083S639100, C083S684000
Reexamination Certificate
active
06240818
ABSTRACT:
FIELD OF USE OF THE INVENTION
The invention relates to a hydraulically or mechanically driven precision blanking press with knife-edged ring cylinder and counterstay cylinder.
In the precision blanking of workpieces, smooth section surfaces free of scores and of fragmentation can be produced and fractures, such as usually occur during normal blanking, are avoided. An essential feature of precision blanking is the imprinting of a knife-edged ring parallel to the cutting line on the blanking screen side, so as to avoid an afterflow of the material here; the knife-edged ring is imprinted by the knife-edged ring cylinder. During the precision blanking process, the workpiece is pressed against the upper die from below by means of a special sheet counterstay, referred to below as “counterstay”.
PRIOR ART
In conventional precision blanking presses, the force of the knife-edged ring cylinder, which is arranged in the upper crosshead as a machine stand, counteracts the cutting force. The counterstay cylinder, which is integrated in the slide or in the working piston, presses the workpiece against the die upper part; the counterstay supporting force counteracts the cutting force. The counterforce of the knife-edged ring cylinder amounts to 50% and that of the counterstay to 25% of the working force. These counterforces are converted into heat during the working stroke by virtue of the positive displacement principle and additionally reduce the cutting efficiency. In a conventional precision blanking press with a drive power of, for example, 100 kW, a cooling capacity of about 80 kW is installed, and the cutting force of, for example, 4000 kN may be reduced by 3000 kN.
OBJECT OF THE INVENTION
In light of the precision blanking presses known hitherto, with the unfavorable relation between the overall energy consumption and the actually usable cutting capacity, the problem on which the invention is based is to reduce the energy losses sharply on a precision blanking press. At the same time, the imprinting of the knife-edged ring and the bracing of the workpiece relative to the upper die must be ensured during the cutting operation of the precision blanking press.
ESSENCE OF THE INVENTION
According to the invention, the knife-edged ring cylinder is integrated in a crossmember above the upper crosshead and is connected fixedly to the slide, so that said cylinder moves upward synchronously with the slide. The counterstay cylinder is arranged between the slide and the lower crosshead of the stand. The piston of the knife-edged ring cylinder is held in its lower position by means of a pressure medium actuated supporting cylinder and thereby remains constantly in contact with the thrust bolts of the upper die. Due to the fastening of the supporting cylinder piston on the stand and integration in the knife-edged ring cylinder piston, the latter can move away upward during the working stroke in the event of pressure relief. At the end of the working stroke, the pressure medium actuated supporting cylinder pushes the knife-edged ring cylinder piston into its lower basic position and simultaneously strips off the knife-edged ring blanking screen.
The piston of the counterstay cylinder is held in its upper position by means of a pressure medium actuated supporting cylinder, with the result that said piston remains constantly in contact with the thrust bolts of the lower die. By the fastening of the supporting cylinder piston to the slide and integration in the counterstay cylinder piston, the latter can move away downward during the working stroke in the event of pressure relief. At the end of the working stroke, the pressure medium actuated supporting cylinder pushes the counterstay piston into its upper basic position and simultaneously thrusts the precision blanking part into the die space.
By virtue of the above-mentioned arrangement, the working force of the main drive can be utilized fully in order to cut out the precision blanking part. A precision blanking press, the energy losses of which are sharply reduced, is therefore now available. This is achieved, in particular, by the arrangement of the knife-edged ring cylinder and counterstay cylinder which, during the working stroke of the slide, clamp the blanking screen and the precision blanking part respectively, without a stroke being executed. No relative movement occurs between the knife-edged ring cylinder and the slide during the working stroke; the knife-edged ring cylinder supporting forces are absorbed by the slide. The working force of the main drive is not reduced by the knife-edged cylinder pressing force. At the same time, there is no relative movement between the counterstay cylinder and the stand during the working stroke; the counterstay cylinder supporting forces are absorbed by the stand. The working force of the main drive is not reduced by the counterstay cylinder pressing force.
REFERENCES:
patent: 2547118 (1951-04-01), Hart
patent: 2642138 (1953-06-01), Macewka
patent: 3564959 (1971-02-01), Harada
patent: 3570343 (1971-03-01), Wolnosky
patent: 3611854 (1971-10-01), Gilev
patent: 3771396 (1973-11-01), Im
patent: 4043236 (1977-08-01), De Jong
patent: 4611483 (1986-09-01), Hadaway
patent: 4662256 (1987-05-01), Hicks
patent: 4934230 (1990-06-01), Wallis
patent: 5247862 (1993-09-01), Haack
patent: 5692423 (1997-12-01), Hachikawa et al.
patent: 5749279 (1998-05-01), Gardner
patent: 370618 (1963-07-01), None
patent: 1249805 (1967-09-01), None
patent: 12595 (1967-09-01), None
Bachman & LaPointe P.C.
Feintool International Holding AG
Flores-Saánchez Omar
Rachuba M.
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