Fail-safe automatic sliding operation control apparatus for press
AssigneeThe Nippon Signal Co., Ltd.
InventorsKoichi Futsuhara, Toshihito Shirai, Masayoshi Sakai
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Abstract
The present invention relates to a fail-safe automatic sliding operation control apparatus for a press. The entrance and withdrawal behaviors of an operator's hand relative to danger zones (D, D.sub.N) on a bolster of the press are detected by an output generation configuration of two optical curtains. A signal for permitting a lowering operation of the slide is generated when the operator's hand is withdrawn from the danger zones (D, D.sub.N).
Claims28
A fail-safe automatic sliding operation control apparatus for a press in which a work located on a bolster is processed by downwardly moving a slide to the work, comprising:
- first detecting means for detecting entry of a human body within a first danger zone which is established to include the bolster;
- second detecting means for detecting entry of the human body within a second danger zone which is established outside of said first danger zone to include said first danger zone;
- withdrawal detection means for generating a human-body-withdrawal-detection-signal indicative of withdrawal of the human body from said first and second danger zones, when a first human-body-absence-detection-signal is generated by said first detecting means and thereafter a second human-body-absence-detection-signal is generated by said second detecting means;
- and
- actuation control means for generating an automatic actuation signal for the slide when said human-body-withdrawal-detection-signal is generated by said withdrawal detection means.
A fail-safe automatic sliding operation control apparatus for a press provided with a switching circuit for controlling o opening and closing of a power supply circuit for a movable part of the press, said power supply circuit comprising:
- an emergency cut-off switch which is turned ON simultaneously with an input of an actuation signal of said movable part, and turned OFF at a predetermined OFF delay time after stoppage of said input of said actuation signal;
- and
- two normal cut-off switches which are turned ON at a predetermined ON delay time after an input of said actuation signal, and turned OFF simultaneously with stoppage of said input of said actuation signal;
- wherein said two normal cut-off switches, which are connected in parallel to each other, are connected in series with said emergency cut-off switch, said two normal cut-off switches being alternately turned ON/OFF by signals having a mutually complementary relationship based on said actuation signal;
- and
- said apparatus further comprising control means for keeping closure of said emergency cut-off switch when said two normal cut-off switches are being turned ON/OFF alternately.
Dependencies are inferred from the claim text.