Abstract: A plurality of workpiece holders 52 are attached on a slide plate 71 on a bar 14 and connected to a movable plate 72 by a plate connecting portion 73. The plate connecting portion 73 includes an engaging portion 731 that is provided on the movable plate 72 and an engaged portion 732 that is provided on the slide plate 71 and engaged with the engaging portion 731. By moving a fixed bar 141 downward relative to a movable bar 142, the movable bar 142 is detached and the engagement of the engaging portion 731 with the engaged portion 732 is released. Since both of the movable bar 142 and the slide plate 71 can be detached by a single downward movement of the fixed bar 141, no actuator is required, thereby simplifying the structure.

Abstract: A rotary ring (34) formed such that an outer circumference is eccentric with respect to an inner circumference is provided to an outer circumference of an eccentric drum (333) of an eccentric shaft (33). An adjustment ring (41) formed such that an outer circumference is eccentric with respect to an inner circumference is provided to the outer circumference of the rotary ring (34), and a slide (5) is mounted to the outer circumference of the adjustment ring (41). Since the slide (5) and a slide drive unit (30) are arranged to be superposed substantially at the same height, a distance between the slide drive unit (30) and a lower end of the slide (5) can be reduced and the entire height of a servo press (1) can be reduced. In addition, since the height position of the slide (5) can be finely adjusted by rotating the adjustment ring (41), a press working can be performed with high accuracy.

Abstract: Adhesion and accumulation of spatter onto a covering member that encloses the outer periphery of a torch is minimized and flying of spatter is confined within a narrow area. To this end, a covering member for enclosing a specified angular range of the outer periphery of a plasma torch 9 is provided and an opening portion 35 is formed between every adjacent shielding plates 34 in the covering member.

Abstract: A fixed-side connecting portion 151 is provided on an end of the fixed bar 141 while a movable-side connecting portion 152 is provided on an end of the movable bar 142. An air clamp 16 is housed within the fixed bar 141. By pneumatically driving the air clamp 16 while the movable-side connecting portion 152 is superimposed on an upper side of the fixed-side connecting portion 151, a clamp member 165 protrudes from a case 161 to be downwardly rotated and holds the movable-side connecting portion 152 against the fixed-side connecting portion 151. Since the clamp member 165 is pneumatically driven, a die replacement time can be shortened. In addition, since the air clamp 16 is housed within the fixed bar 141, the size of a transfer feeder 41 can be reduced.

Abstract: Provided is a die cushion controller (40) that controls an ascending/descending speed of a die cushion pad (15) based on a preset pressure pattern (56) and positional pattern (54), in which a position/pressure control switching unit (51) constantly monitors and compares a for-pressure speed command signal ?pc corresponding to a pressure deviation signal ep and a for-position speed command signal ?hc corresponding to a position deviation signal eh, and selects smaller one of those speed command signals to be sent to a speed control unit (53). Since the for-pressure speed command signal ?pc and the for-position speed command signal ?hc are constantly monitored and either one of them is selected, change in pressure and change in position can be accurately recognized to allow switching between a pressure control and a position control quickly, stably, and reliably.

Abstract: A die cushion controlling apparatus for controlling an operation of a cushion pad, which comprises a pad drive mechanism for driving to raise or lower the cushion pad while applying an upward energizing force, a load measuring unit for measuring a load generated in the cushion pad, a time detecting unit for detecting a generating time and a vanishing time of the load, and a control unit for controlling the pad drive mechanism so that a load measured value measured by the load measuring unit follows a preset load pattern during a period from when the time detecting unit detects the generating time of the load until when the time detecting unit detects the vanishing time of the load.

Abstract: A cylinder is formed in the lower portion of a cushion pad, and a piston coupled to an upper end of a rod is slidably contained in the cylinder. The rod is coupled to a rotary shaft of a servomotor. An oil pressure chamber is formed of an inner wall surface of the cylinder and a wall surface of the piston. The axial center of the oil pressure chamber is identical with the axial center of the rod. The pressure oil for alleviating an impact is filled in the oil pressure chamber. The pressure oil filled in the oil pressure chamber absorbs a force operating instantaneously at the cushion pad. According to this structure, the impact generated in a press machine can be alleviated.

Abstract: A die cushion apparatus of a press machine which makes possible to manufacture a plurality of types of products of different sizes by one press machine and capable of minimizing a production facility, and which comprises a plurality of die cushion units, each having a cushion pad and a rise and fall drive unit for vertically driving the cushion pad, that are aligned in a direction perpendicular to a work conveying direction, and a control unit capable of individually and independently controlling the plurality of die cushion units.

Abstract: An overload protection control method for a pressing machine capable of performing overload protection with excellent responsiveness with a simple structure is provided. For this purpose, the overload protection control method includes the steps of driving a slide (4) to reciprocate via a mechanical power transmission mechanism (3) by a servo motor (21), and raising the slide (4) by the servo motor (21) when detecting overload on the slide (4) during pressurization.

Abstract: A die height adjusting device for a pressing machine, which withstands high vibrations and high impacts during pressing work, and is capable of realizing high precision of a slide position, is provided. For this purpose, the die height adjusting device includes an induction motor (9), which performs die height adjustment of a slide (3), and an inverter (17) which performs a speed control of the induction motor. Voltage is applied to the induction motor for a predetermined period of time, and thereby a predetermined amount of die height adjustment is performed.

Abstract: A main arc ignition method capable of extending lives of a plasma electrode and a nozzle. For this purpose, before or immediately after starting arc, a plasma torch is supplied with a plasma gas at least either at a lower flow rate or at lower gas pressure; the plasma gas is switched to a gas flow rate and gas pressure of a time of cutting a work, after pilot arc is ignited between an electrode and a nozzle, or after main arc is ignited between the electrode and the work; and when generation of the main arc between the electrode and the work is detected, a pilot current is interrupted promptly by a semiconductor switch which is interposed in series with a resistance, in a pilot current circuit that is connected to the nozzle and supplies the pilot current to the pilot arc.

Abstract: A slide drive apparatus and a slide drive method for a pressing machine capable of enhancing positioning precision at the time of adjustment of die height, and responding to pressing work at high stroke per minute. For this purpose, the drive apparatus includes a slide (4), a servo motor (21) for controlling slide motion, a mechanical power transmission mechanism (3, 5, 6) for converting rotational power of the servo motor for controlling slide motion into reciprocating motion of the slide, and a servo motor (31) for adjusting die height, which performs die height adjustment of the slide by a position control.

Abstract: A thermal cutting machine and a dust collecting method capable of reducing in size and exhausting fumes and a high pressure gas efficiently. For this purpose, the thermal cutting machine includes a plurality of exhaust chambers (20) which are placed side by side inside a table (3), an exhaust port (23) provided at one end side of each of the exhaust chambers, an exhaust device (25) communicating with each of the exhaust ports, an opening and closing drive device (24b) for opening and closing each of the exhaust ports, an air blow port (21) provided at a position substantially opposing each of the exhaust ports, an air blow device (22) which blows air into the each air blow port (21), and a control device (6) for controlling the opening and closing drive device and the air blow device in synchronism with each other, or controlling them individually, correspondingly to a horizontal position of a torch (4) which is under cutting operation.

Abstract: A die height adjusting device for a pressing machine, which withstands high vibrations and high impacts during pressing work, and is capable of realizing high precision of a slide position, is provided. For this purpose, the die height adjusting device includes an induction motor (9), which performs die height adjustment of a slide (3), and an inverter (17) which performs a speed control of the induction motor. Voltage is applied to the induction motor for a predetermined period of time, and thereby a predetermined amount of die height adjustment is performed.

Abstract: A main arc ignition method capable of extending lives of a plasma electrode and a nozzle. For this purpose, before or immediately after starting arc, a plasma torch is supplied with a plasma gas at least either at a lower flow rate or at lower gas pressure; the plasma gas is switched to a gas flow rate and gas pressure of a time of cutting a work, after pilot arc is ignited between an electrode and a nozzle, or after main arc is ignited between the electrode and the work; and when generation of the main arc between the electrode and the work is detected, a pilot current is interrupted promptly by a semiconductor switch which is interposed in series with a resistance, in a pilot current circuit that is connected to the nozzle and supplies the pilot current to the pilot arc.

Abstract: A thermal cutting machine and a dust collecting method capable of reducing in size and exhausting fumes and a high pressure gas efficiently. For this purpose, the thermal cutting machine includes a plurality of exhaust chambers (20) which are placed side by side inside a table (3), an exhaust port (23) provided at one end side of each of the exhaust chambers, exhaust means (25) communicating with each of the exhaust ports, opening and closing drive means (24b) for opening and closing each of the exhaust ports, an air blow port (21) provided at a position substantially opposing each of the exhaust ports, air blow means (22) which blows air into the each air blow port (21), and control means (6) for controlling each of the opening and closing drive means and each of the air blow means in synchronism with each other, or controlling them individually, correspondingly to a horizontal position of a torch (4) which is under cutting operation.

Abstract: An overload preventive device is capable of preventing elevation of preload pressure due to sticking action or break-through load of a hydraulic cylinder of a press machine. A delay valve for opening when the internal pressure of the load detecting circuit is lower than the minimum pressure to be maintained continuously over a specified time is interposed between a hydraulic pump for supplying pressurized oil of a specified pressure to a load detecting circuit.