| 摘要 |
1,007,285. Locking switches; press-button retractive switches. ROTORK ENGINEERING CO. Ltd. June 8, 1964 [June 7, 1963], No. 22842/63. Heading H2B. In a valve actuator having an electric rotor and a control panel 11 including three pushbuttons 12, 13, 14 for controlling the energiza. tion of the motor, a cover assembly 22 is mounted on the actuator casing 10 over the' control panel 11, the cover assembly including an operating knob 31 and a selector disc 37 rotatable therewith to screen push-buttons 12, 14 and prevent manual operation thereof in certain positions. The spring-loaded push-buttons 12, 14 operate switches 19, 20 through plungers 15 to sense energization of the motor and opening or closing of the valve, and knob 31 is in certain rotational positions thereof movable axially to actuate a stop switch 21 through plungers 34, 15 to cause de-energization of the motor. The motor is alternatively operable by remote control means. When the knob 31 is turned to the " Full control " position, Fig. 1 (not shown), apertures in the selector disc 37 are aligned with corresponding apertures 25, 27 in a front plate 24 of the cover assembly bolted to the main actuator body, so that pushbuttons 12, 14 may be actuated manually and knob 31 may be depressed to actuate pushbutton 13. When however the knob is rotated to the position shown in Fig. 4, the selector disc 37 screens the push-buttons 12, 14 while at the same time the knob is locked in an outer position by means of pins 41 thereon engaging over lugs 43 around the central aperture 26 in the plate 24. Similarly, when the knob is turned to the " Stop locked " position lugs 43 so engage with the pins 41 that the knob is held depressed and the push-button 13 is permanently operated. In -the " Stop and remote " position the lugs 43 do not engage the pins 41 so that the knob 31 may be depressed though push-buttons 12 and 14 cannot be directly manually-operated. A spring- loaded pivoted lever 56 passes through in the cover 23 and engages one of a plurality of slots round the periphery of the selector disc to prevent unauthorized rotation of the disc, the lever being locked in position by a padlock 62. Specification 939,353 is referred to. |
