in alignment with landing doors 14 and 15 respectively a door opening clutch assembly 18 attached to each car door 12 and 13 is in engaging alignment with a pair of landing door unlocking and opening roller assemblies 21 when car 10 stops at a given landing car doors 12 and 13 are opened by means of clutch assemblies 18 which because of their engagement with roller assemblies 21 on landing doors 14 and 15 also unlock and open landing doors 14 and 15 referring now to fig2 car doors 12 and 13 are illustrated in their closed position a door opening power drive assembly 40 is affixed to the top of car 10 referring now to fig4 drive assembly 40 preferably comprises an electric motor 42 coupled to a speed reducing torque multiplier 44 preferably having a speed reduction ratio of 29 to 1 although any speed reducing apparatus may be used it is preferable that a u201c cyclo u201d or cyclodial type speed reducer be used a suitable cyclo speed reducer has been found to be cyclo speed model cnhx 4100y 29 marketed by sumitomo machinery corporation of america the cyclo speed reducer operates by the action of an eccentric cam mounted on the input shaft of the speed reducer the eccentric cam rotates within a bore inside a cyclodial disc forcing the cyclodial disc to roll inside a ring gear housing as the input shaft and the eccentric cam rotate the cyclodial disc advances a given distance in the opposite direction thereby producing a speed reduction the amount.