Inner locking cylinder with captive key
US4254648A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 21, 1979 |
| Grant date | Mar 10, 1981 |
| Priority date | — |
| Expiry date | Feb 21, 1999 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T70/7768
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A dead bolt lock set is designed to be key actuated on the inside as well as on the outside of the door. For the inside there is an inside tailpiece in engagement with a drive slot in the dead bolt hub. A lost motion circumferential recess on the inside tailpiece provides stops at positions such that when the key is inserted on the inside and turned to lock the dead bolt by action of a micro drive pin, the key cannot be returned in reverse direction to key release position without unlocking the dead bolt. Consequently, the key must remain captive in the inside keyway to keep the dead bolt locked because of being held in the cylinder by the pin tumblers. When the lock has been locked from the outside, the drive slot in the head of the tailpiece is rotated out of line with the inside key slot. Under this condition when unlocking from the inner trim, the tailpiece and washer are forced inward by the key tip compressing the conical spring and allowing full key insertion. Bolt retraction (unlocking) may be accomplished by rotation of the key in the bolt extended direction until the key tip aligns with the tailpiece drive slot, then rotating the key back to the vertical (withdrawn) posit…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.