§ 7.236. Stops.
(a) Up limit stop. Two separate automatic stop devices shall be provided to cut off the power and supply the brake when a loaded step passes the upper terminal landing, in accordance with the following:
(1) One automatic stop device shall consist of a switch mechanically operated by the belt or step roller. The other shall consist of one of the following:
(i) A roller switch placed above and out of line with the first limit switch.
(ii) A photocell and light source (electric eye).
(iii) A switch actuated by a lever, rod or plate, the latter placed above the head pulley so as to just clear a passing step.
(2) After the manlift is stopped it shall be necessary to reset the automatic stop manually. The device shall be so located at the top landing that a person resetting it shall have a clear view of both the up and down-runs of the manlift. It shall not be possible to reset the device from any step or platform.
(3) The stopping device shall function so that the manlift is stopped before the loaded step has reached a point 24 inches above the top terminal landing.
(4) Electrical requirements are as follows:
(i) When switches open the main motor circuit directly they shall be of the multiple type.
(ii) When photoelectric devices are used they shall be so designed and installed that the failure of the light sources, light sensitive element, or of any other vacuum tubes employed in the circuit will result in shutting off the power to the driving motor.
(iii) Unless of the oil-immersed type, controller contacts carrying the main motor current shall be copper to carbon, except when the circuit is broken at two or more points simultaneously.
(iv) Electric manlifts, operated by polyphases alternating current motors, shall be provided with relays of the potential type or other approved devices, which prevent starting the motor if the phase rotation is in the wrong direction, or if there is a failure in any phase.
(b) Down limit stop. An automatic stop device shall be provided to cut off the power and apply the brake if a loaded step passes the bottom terminal landing.
(c) Emergency stop. An emergency stop means shall be provided, in accordance with the following:
(1) The stop means shall be within easy reach of the ascending and descending runs of the belt.
(2) The stop means shall be so connected with the control lever or operating mechanism that it cuts off the power and applies the brake when pulled in the direction of travel.
(3) The stop may consist of a cotton rope with a wire center, manila or sisal rope, or may be made of suitable lengths of metallic pipe or tubing. If rope is used, it shall be not less than 3/8 inch in diameter. Wire rope, unless marlin-covered, shall not be used.
(4) The emergency stop may be used for normal starting and stopping where the manlift does not run continuously.
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