To provide an electric thumb-turn device capable of being manually operated by using a key or a thumb-turn, together with enhanced security against picking.
A clutch plate 35 is fitted into the interior of a circular tube of a thumb-turn grip 17 connected with a dead cam 48 of a lock case 12 for driving a dead bolt 31 via a thumb-turn rod 18. The clutch plate 35 is provided with a hole 46 into which the thumb-turn rod 18 is inserted, and is further provided with a protrusion 44 engaged with a protrusion 26a formed toward the inside of the circular tube 20 of the thumb-turn 17. The thumb-turn grip 17 is turned by turning the clutch plate 35 by a motor 36 to lock and unlock the lock case 12. When the clutch plate 35 is turned reversely to release from engagement after the lock case is locked or unlocked, the thumb-turn 17 can be manually operated. When the engagement is kept as it is, the rotation of the thumb-turn 17 is prevented, thus security against picking is enhanced.
Torii Kazuhisa
Takayoshi Tagawa
Higashio Masahiro