Safety device for elevator

Claim 1

A SAFETY DEVICE FOR AN ELEVATOR DRIVEN BY A GENERATOR-MOTOR SET CONNECTED IN WARD-LEONARD SYSTEM, AND RUNNING BETWEEN THE UPPER-MOST AND THE LOWEST END STAGES OF A BUILDING, WHEREIN TWO SPEED CONTROLLING CIRCUITS ARE CONNECTED PARALLEL TO EACH OTHER ACROSS A COMMON DIRECT CURRENT POWER SOURCE $ AND $, NAMELY, (I) A FIRST SPEED CONTROLLING CIRCUIT COMPRISING A SHUNT FIELD WINDING (GSF) OF SAID GENERATOR (G) AND A RHEOSTAT (GFR) IN SERIES WITH SAID SHUNT FIELD WINDING (GSF), AND (II) A SECOND SPEED CONTROLLING CIRCUIT COMPRISING A SHUNT FIELD WINDING (MSF) OF SAID MOTOR (M) AND A RHEOSTAT MFR IN SERIES WITH SAID SHUNT FIELD WINDING (MSF), SAID FIRST AND SECOND SPEED CONTROLLING CIRCUITS COOPERATE TO ACT AS A NORMAL DECELERATING AND STOPPING DEVICE FOR AN ELEVATOR CAGE WHEN IT APPROACHES ONE OF THE INTERMEDIATE STAGES AND THE UPPER-MOST AND LOWEST STAGE, AND A THIRD SPEED CONTROLLING CIRCUIT, WHICH OPERATES WHEN AN ELEVATOR CAGE APPROACHES ANY ONE OF SAID BOTH END STAGES, AND WHICH IS CONNECTED ACROSS SAID DIRECT CURRENT POWER SOURCE, SAID THIRD SPEED CONTROLLING DEVICE COMPRISING POSITION-DETECTING CONTACTS (UL) AND (DL), EACH ADAPTED TO DETECT THE APPROACH OF THE ELEVATOR CAGE TO THE UPPER-MOST STAGE AND TO THE LOWEST STAGE RESPECTIVELY, AN OVERSPEED DETECTING CONTACT (GRS) WHICH DETECTS THE SPEED OF AN ELEVATOR CAGE WHEN IT EXCEEDS A PREDETERMINED LIMITED SPEED AND AN EMERGENCY DECELERATING RELAY (3M), SAID EMERGENCY DECELERATING RELAY (3M) BEING CONNECTED IN SERIES WITH BOTH OF SAID CONTACTS (UL) AND (DL) AND SAID CONTACT (GRS).