Method and device for detecting plate thickness in press
First Claim
1. A plate thickness detection method for a press, comprising the steps of:
- descending a ram from a certain height position;
detecting pressure of hydraulic oil discharged from a rod-side cylinder chamber at this time;
detecting time at which a punch contacts with a workpiece on the die, from a change of the detected pressure;
detecting upper and lower positions of the ram at this time;
obtaining a plate thickness of the workpiece from the detected height position of the ram and a set height between the certain height known in advance and an upper surface of the die; and
vertically moving the ram, to which the punch is attached, based on the obtained plate thickness of the workpiece, and pressing the workpiece cooperatively by the punch and the die.
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Accused Products
Abstract
A ram (5U) is descended by a self-weight pressure of a rod-side cylinder chamber (19) of a hydraulic cylinder (13R) which vertically moves the ram (5U) is detected by oil pressure detection means (21), and a determination section (65) detects a position at which a punch (P) attached to the ram (5U) contacts with an upper surface of a workpiece (W), from a change of this detected pressure. If the upper surface of the workpiece (W) is detected, a plate thickness calculation section (67) calculates a plate thickness of the workpiece (W) based on an upper surface position of a die (D) known in advance and stored in a memory (63).
17 Citations
12 Claims
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1. A plate thickness detection method for a press, comprising the steps of:
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descending a ram from a certain height position;
detecting pressure of hydraulic oil discharged from a rod-side cylinder chamber at this time;
detecting time at which a punch contacts with a workpiece on the die, from a change of the detected pressure;
detecting upper and lower positions of the ram at this time;
obtaining a plate thickness of the workpiece from the detected height position of the ram and a set height between the certain height known in advance and an upper surface of the die; and
vertically moving the ram, to which the punch is attached, based on the obtained plate thickness of the workpiece, and pressing the workpiece cooperatively by the punch and the die. - View Dependent Claims (2, 3, 4)
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5. A plate thickness detection method for a press, comprising the steps of:
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descending a ram from a certain height position while controlling a descent speed, and detecting a ram descent position;
detecting a ram stop position from a change of this detected ram position;
determining the detected stop position as a position at which a punch contacts with a workpiece on the die;
obtaining a plate thickness of the workpiece from the ram position which is determined as the position at which the punch contacts with the workpiece, and from a set height of a difference between the certain height known in advance and an upper surface of the die; and
vertically moving the ram, to which the punch is attached, based on the obtained plate thickness of the workpiece, and pressing the workpiece cooperatively by the punch and the die.
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6. A plate thickness detection apparatus in a press, the detection apparatus comprising:
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ram position detection section to detect upper and lower positions of a ram to which a punch is attached;
oil pressure detection section to detect pressure of hydraulic pressure discharged from a rod-side cylinder chamber of a hydraulic cylinder which vertically moves the ram;
a determination section detecting a position at which the punch contacts with a workpiece, from a change of the pressure detected by the oil pressure detection section; and
a plate thickness calculation section calculating a plate thickness of the workpiece, from the ram position which is determined by the determination section as position at which the punch contacts with the workpiece and from a set height of a difference between a certain height of the ram known in advance and an upper surface of the die, wherein the ram is thereby vertically moved by the hydraulic cylinder, and the workpiece is pressed cooperatively by the punch and the die. - View Dependent Claims (7)
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8. A plate thickness detection apparatus in a press, which vertically moves a ram, to which a punch is attached, by a hydraulic cylinder actuated by hydraulic oil from a two-way pump and which presses a workpiece cooperatively by the punch and a die, the apparatus comprising:
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ram position detection section to detect upper and lower positions of the ram;
oil pressure detection section, provided halfway along a hydraulic circuit which connects a rod-side cylinder chamber of the hydraulic cylinder which vertically moves the ram, to the two-way pump, for detecting pressure of the hydraulic oil discharged from the rod-side cylinder chamber;
a determination section determining a position at which the punch contacts with the workpiece, from a change of the pressure of the hydraulic oil detected by the oil pressure detection section; and
a plate thickness calculation section calculating a plate thickness of the workpiece, from a ram position which is determined by the determination section as the position at which the punch contacts with the workpiece and from a set height of a difference between a certain height of the ram and an upper surface of the die. - View Dependent Claims (9, 10, 11)
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12. A plate thickness detection apparatus in a press, which apparatus vertically moves a ram, to which a punch is attached. and which presses a workpiece cooperatively by the punch and a die, the apparatus comprising:
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ram position detection section to descend the ram from a certain height position while controlling a descent speed, and for detecting a ram descent position;
a determination section detecting a ram stop position from a change of the ram position detected by the ram position section, and determining this detected stop position as a position at which the punch contacts with the workpiece; and
a plate thickness calculation section calculating a plate thickness of the workpiece, from the ram position determined by the determination section as the position at which the punch contacts with the workpiece and from a set height of a difference between the certain height known in advance and an upper surface of the die.
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Specification