PURPOSE: To raise the safeness of an oil-pressure hammer system by providing a means to send out a specific value alone among the detected values of dropping heights obtained by continuous plural times' dropping operations to the former stage of the displayer of dropping heights of the hammer.
CONSTITUTION: When oil is sent into the lower chamber 3a of a rod cylinder 3 and a piston 3c is raised, rods 1 and 2 are raised to pull up a ram 4. As the rods 1 and 2 go up, a bar 10 is raised, and when a photoelectric switch 14 passes through the small holes 13, 13', 13"... of the bar 10 in order, on-off operations of the switch 14 are repeated the passage of light. The number of the repeating times is counted by a counter 16, the pulling-up distance of the ram 4 is calculated by an arithmetic unit 17 to calculate the dropping height of the ram 4, and the output of the unit 17 is passed through a holding circuit 19 through a gate 18. The display of the displayer 20 can thus be held at maximum peak value for 1W2sec to enable reading to be sufficiently made.
TAKAHASHI SHINOBU
YOSHIDA KAZUYUKI
MIZUNO TOSHIYUKI
