Latch bolt locking mechanism for fire door locksets
Patent 4183565 Issued on January 15, 1980. Estimated Expiration Date: 
August 28, 1998. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
August 28, 1998. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 1520509 1541093 1617813 3026703 3705739 Lock assembly for automatically dead bolting a closure Patent #: 4012066 InventorAssigneeApplicationNo. 05/937504 filed on 08/28/1978US Classes:292/163, Spring projected292/150Sliding catchExaminersPrimary: Moore, Richard E.International ClassE05B 65/10 (20060101)AbstractTo lock the head of a latchbolt in extended, or locked position therein to prevent opening of a door in case of fire the latch bolt head is provided with a spring driven locking pin reciprocatably mounted in a transverse direction. In the extended locked position of the latch bolt head the locking pin is in alignment with but withdrawn clear of a hole in the latch bolt case. At the inside end of the locking pin is a groove and a fusible pin normally engages the groove holding the locking pin in withdrawn position. This permits normal latch bolt action. When the fusible pin melts because of heat from a fire the locking pin is released and driven by spring action into the hole in the latch bolt case to physically bar withdrawal of the latch bolt, and consequent opening of the door. | |
