To secure the depth of marking and to steadily execute retreat of marking pin without a large prolongation of cycle time by providing a sensor for detecting the retreat of marking pin at the rear end of marking pin, detecting the retreat of marking pin and making the whole of the head part slip backward and retreat in case of no detection of retreating.
Regarding the retreat of marking pin 1, the rear end of marking pin is to be confirmed by the retreat detecting sensor 11 which is a non-contact type proximity switch. In the case the retreat of marking pin 1 is defective, the pin 1 and the cast billet are forcedly separated by retreating the whole of the head part 7 by a cylinder, and then the retreat of marking pin 1 is steadily executed by a coil spring 3, and thus the selection of following marking pin is made available by turning a revolver 2 with a pulse motor 4. The detecting timer of retreat detecting sensor 11 is limited to 0.3 second from the retreat of impact cylinder 5, and in case that the timing exceeds the limit, the control unit decides that the retreat of pin is defective.
AO YOJI
KAWADA SHIYUNSETSU
OKURA ENG KK
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