Limit switches as special type of position switches are offered for different functions. In every lift one respectively two emergency limit switches must be used.
The small shaft limit switch ESK is a safety switch with forced actuation. It is preferably used as emergency limit switch in the highest or lowest landing of lifts. On other moving parts predetermined positions may be registered as well. The switch may be actuated to the left or right direction and is equipped with a spring return to the centre position. The actuation is made at the roller lever by fixed operating ramps.
The direction limit switch US has the features of a safety switch with forced actuation. It has three switching positions with stay-put feature and therefore retains the last position. The switch is preferably used as robust floor switch and signals the position of the car to the floor. The limit switch is actuated at the roller lever by change-over cams.
The zone limit switch UGS has the features of a safety switch with forced actuation. It has three switching positions with stay-put feature and therefore retains in the last position. The zone limit switch is used to bridge the switch for locking mechanism if a door interlock is operated by stationary cams, so that the lift can move a short distance with unlocked doors. The limit switch is actuated at the roller lever by change-over cams.
The terminal limit switch ES is a safety switch with forced actuation. It is preferably fixed on the lift car. With the operating ramps mounted above and /or below in the shaft, the corresponding travel direction may be interrupted. The switch may be actuated to the left or right hand side and interrupts thus one assigned contact each. By guided compression springs a return to the center position of the roller lever is made.
The levelling limit switch FS is a safety switch with forced actuation. With different contact arrangements it can be used for different applications. The switch may be actuated to the left or right hand side. By guided compression springs a return to the center position of the roller lever is made.
The terminal limit switch FES is a safety switch with forced actuation. It is preferably used as limit switch in the highest or lowest landing of lifts. The return to the initial position is done by a guided compression spring. The limit switch is actuated at the roller lever by fixed operating ramps.
The direction limit switch US-EX is designed as a safety switch with forced opening and intended for the use in explosion-endangered areas. It complies with the requirements of the series of standards EN81-20 / EN81-50. It has three switching positions with stay-put features, whereby the last switching position is retained. The direction limit switch signals the position of the car to the floor (at floor level, above, below).
The emergency limit switch FES-EX is a safety switch with forced actuation and intended for the use in explosion endangered areas. It fulfils the requirements of the series of standards EN81-20 / EN81-50. It has two switching positions with spring return to the original position. The emergency limit switch is needed for switching off the lift if, in the event of a fault the lift car moves beyond the terminal landing.
Sliding ramps operate limit switches of spring return types. The roller at the roller lever is brought by the inclined contact surface into the corresponding switching position. If the sliding ramp is removed, the switch returns to its original position. Operating ramps are used for direction limit switches. If the roller of the roller lever leaves the operating cam, the stay-put feature of the direction limit switch ensures that it remains in the last switching position. The long versions of both types of ramps are designed for high speed lifts, the short versions are designed for slow speed lifts.
