A push-button switch 5 disposed in a switch case 3 has c-contacts and a normally close contact electrically connected with a terminal block 9 via conductors 39. Leading ends 23 of cores of a cable 7 introduced into the switch case 3 are inserted in insertion holes 49a, 49b formed in the terminal block 9. Screws 53a, 53b mounted to the terminal block 9 are tightened to press the leading ends 23 of the cores against conductive connection portions, on one side, in the insertion holes 49a, 49b, thereby to establish electrical connection.

A push-button switch provided with a hollow push button (2), a case (3) supporting it, and a switching mechanism (6) having a first contact (41) disposed within the case (3) and a second contact (51) disposed opposite to the first contact (41), with one of its ends being inserted into a hole (2a) of the push button (2). Within a hole (61a) formed in an inserted section (61) of the switching mechanism (6), a slide block (8) is provided slidably in a direction crossing the direction in which the push button (2) is pushed. A slope (8a) capable of engaging with a slope (2b) of the hole (2a) of the push button (2) is formed on the slide block (8). A coil spring (return spring) (12) for energizing a shaft (62) of the switching mechanism (6) so as to abut the push button (2) is provided on the bottom (31) of the case (3). This configuration enables the push button (2) to take up a first OFF state, an ON state and a second OFF state in order of depression.

Erfindungsgemäß wir ein NOT-AUS-Befehlsgerät (1) mit einem Öffner-Schaltelement (4) und einem hierzu in Reihe liegenden Schließer-Schaltelement (5) ausgeführt, die beide mittels eines Schiebers (6) betätigbar sind. Nur bei ordnungsgemäßer Ankopplung des Schiebers (6) an dem Betätiger (2) des NOT-AUS-Befehlsgeräts (1) kann durch Betätigung der gleichzeitge EIN-Zustand beider Schaltelemente (4,5) erreicht werden, in dem der Verbraucherstromkreis geschlossen ist. Hierdurch wird die sichere NOT-AUS-Schaltung durch Öffnen des Öffner-Schaltelements (4) bei weiterer Betätigung gewährleistet.

A deadman switch (4) comprises a push plate (5), a shaft (7) provided on the push plate (5), a dog plate (6) fitted onto the shaft (7), a plurality of bosses (34), a spacer (9) fitted onto the shaft (7), a spring (8) provided on an outer periphery of the shaft, and three-point type limit switches (41, 42) mounted on a rear plate (3) and constructed such that the dog plate (6) can engage with dogs (41a, 42a) to turn the limit switches off with the dogs kept free, to turn the limit switches on when the dog plate (6) pushes the dogs (41a, 42a) slightly, and to turn the limit switches off when the dog plate (6) further push the dogs (41a, 42a) against the spacer (9) and the spring (8). It is possible to provide a fail-safe hand-held operating unit for robots which is exceedingly safe, since the limit switches are surely turned off in a panic such as runaway of robots and the like even when an operator strongly holds the hand-held operating unit tight in his hand.

A three-position switch is provided with a push button (11) which is elastically supported by double springs (21 and 22), switch operating lever (3) which is extended inward in a direction almost perpendicular to the push button (11) and has a projection (31) projecting in the lateral direction at its front end, normally-on switch (41) which is wiped in a direction almost perpendicular to the direction of the movement of the lever (3), turned on by being pressed by the projection (31) only when the switch (41) is pressed, and turned off when the button (11) is in a free state and the button (11) is strongly depressed and largely wiped.