RELAY-CONTACT LIFT PROTECTION SYSTEM (VERSIONS) Russian patent published in 2003 - IPC

FIELD: passenger lifts. SUBSTANCE: invention relates to safety devices of passenger lifts provided with mechanical story switches in electric circuits. According to first design version intended for use in two-speed lifts with double-wing doors of lift well and mechanical story switches, special relays are introduced to prevent getting of unauthorized persons into lift well, and control relays connected in parallel pairs on each story by make contacts of lock switches of left-hand and right-hand wings of well doors, and diode. Shunt-magnet 120 mm long is installed at side of lift, cabin opposite to sealed contact at distance of 5 mm from said contact. According to second design version intended for use in one -speed lifts with mechanical story switches and single-swing well doors, special relays to prevent getting of unauthorized persons into lift well, control relays and diode are introduced. Both devices are furnished additionally with signal lamp indicating that device is sound and with additionally break contact of relay to prevent getting of unauthorized persons into lift well, and resistor is placed between winding of relay to prevent getting of unauthorized persons into lift well and first break contact of device two-pole switch to reduce voltage after resistor to 24 V. Control relay and relay to prevent getting of prevent getting of unauthorized persons into lift well monitor each other revealing possible failure of any winding of both said relays. In case of unauthorized getting of a person into lift well, signal is supplied to energize said relay which will open its contact in electric circuit of lift well door control relay and lift will immediately stop. EFFECT: improved safety of lifts, reduced cost of device. 4 cl, 3 dwg