Abstract: An excitation current detection circuit is disclosed. A transformer comprises a primary winding, an auxiliary winding, and a secondary winding. A first voltage detector detects a positive voltage of an auxiliary winding voltage. A second voltage detector detects a negative voltage of the auxiliary winding voltage. A first voltage controlled oscillator generates a first clock with a frequency proportional to the positive voltage during a period when the auxiliary winding voltage is the positive voltage. A second voltage controlled oscillator generates a second clock with a frequency proportional to the negative voltage during a period when the auxiliary winding voltage is the negative voltage. A counter outputs a counter value, which is added in one of cycles of the first clock and the second clock and subtracted in the other cycle of the first clock and the second clock as a detected value of an excitation current.

Abstract: A transfer press machine which can accurately and promptly check interference and can be easily handled is provided.

Abstract: A transfer press machine which can accurately and promptly check interference and can be easily handled is provided.

Abstract: A plurality of closing cylinder devices are provided between a bolster of a press machine and a bed containing a lower mold of a hydroforming device. An upper mold is attached to a slide of the press machine. The upper mold and lower mold come together to form a cavity having the shape of the exterior of the desired molded product. A closing block, being movable between a first position which is between the slide and a crown of the press machine, and a second position, which avoids the slide, permitting free movement of the slide from the crown to the lower mold. When a material to be hydroformed is place in the lower mold, the upper mold is lowered. The closing block is fit into its first position, thereby restricting movement of the slide in the vertical direction. A inner work pressure is provided by a fluid inside the material to be molded.

Abstract: A high precision, all-purpose, double action hydraulic press, which can control the speed, position, and parallelism of each slide, can conduct mold exchanges easily, and prevent the breakthrough phenomenon is provided with an outer slide 4, an inner slide 6, drive cylinders 8 and 9 which drive each of the slides, position detection devices 14 and 15 which detect the position of each of the slides, push pins 13, a damper cylinder 10 which prevents breakthrough phenomenon, and a die plate 5 which is equipped with push pins 13. By controlling the flow in the hydraulic pressure circuit which is connected to each of the drive cylinders, the speed, position, and parallelism of each of the slides are controlled.

Abstract: A hydraulic press has closed loop feedback control on a slide, a slide pad and bolster cylinders. Hydraulic cylinders actuating various components of the press are controlled according to ideal position estimates to produce consistent and precise pressing action. A closed loop control consists of an ideal position/pressure value generator, a position/pressure detector and an arithmetic unit comparing the ideal and actual position/pressure values. Using the ideal and actual comparison result, the arithmetic unit produces a control signal to drive a cylinder to a desired position/pressure. The hydraulic press is capable of performing several operations on a workpiece in one press cycle, an improvement over presses requiring several operation steps or die changes. The bolster cylinders augment clamping force, reduce shock, and improve die alignment to produce better results with less wear on press components.

Abstract: A cassette loading device of a tape recorder comprises a cassette holder and a pair of link mechanisms which are disposed to the right and to the left of the cassette holder and which operatively connect the cassette holder to the stationary portions of the tape recorder so as to allow the cassette holder to smoothly move between a cassette loading position and a disengaged position giving easy access to the cassette. Each of the pair of link mechanisms includes a first link arm that has one end rotatably mounted on the corresponding stationary portion and an opposite end slidably mounted on the cassette holder for travel within communicating straight and arcuate slot portions; a second link arm has one end rotatably mounted on the cassette holder and an opposite end slidably mounted on the corresponding stationary portion. The first and second link arms of each link mechanism intersect and pivot each other at their intersection.