| 摘要 |
PURPOSE:To raise the efficiency of striking by exactly confirming the dropping height of a ram and automatically setting the dropping height to a desired value by a method in which the measured value of the dropping height of the ram is compared with a set value, and a solenoid valve is controlled so as to make both the values to coincide. CONSTITUTION:When oil is sent into the lower chamber 3a of a cylinder 3 and a piston 3c is raised, rods 1 and 2 are also raised to pull up a ram 4. The actions of the rods 1 and 2 coincide with the action of a bar 10. When a photoelectric switch orderly passes through he plural small holes of the bar 10, on-off switching is repeated by the passage of light, the number of repeating times is counted by a counter 16, and the count value is multiplied by the distance between the small holes of the bar 10 to calculate the actually measured value of the dropping height of the ram 4 in an arithmetic unit 17. In a comparator 21, the set value of a setter 18 is compared with actually measured value in the unit 17 and a control signal (e) is sent out so as to make both values coincide. The solenoid valve 23 is then controlled by a valve drive circuit 22 to cause the dropping height of the ram to approach the set value. |
