Door lock

• US 3,912,310 A
• Filed: 03/22/1974
• Issued: 10/14/1975
• Est. Priority Date: 03/22/1974
• Status: Expired due to Term

• Current Assignee: M.A.G Engineering and Manufacturing Company Incorporated
• Original Assignee: Thomas J. Dugan
• Inventors: Dugan, Thomas J.
• Primary Examiner(s): Moore, Richard E.
• Application Number:
  US05/453,585
• Time in Patent Office: 571 Days
• Field of Search: 292/169.14,169.15,192,207,341.15
• US Class Current: 292/169.14
• CPC Class Codes: E05C 1/163 Cylindrical or tubular latches
• CPC Class Codes: Y10T 292/0982 Bolt blocking or disabling means

Abstract

A tamper-proof door lock having a beveled latch bolt which is extended by spring pressure for latching engagement with a keeper plate on the door jamb upon closing of the door and is retractable by rotation of the door handle to open the door. The lock embodies locking means, releasible by door handle rotation, for locking the latch bolt against retraction by insertion of a shim or blade between the door edge and keeper plate. The latch bolt of the described lock is locked in its extended latching position by extension of a locking member carried by the bolt to a locking position behind the keeper plate. Rotation of the door handle to open the door effects initial retraction of the locking member and then retraction of the latch bolt.

Claims

1. A lock for a hinged door comprising:

a housing, a latch bolt having a beveled outer end and movable longitudinally in said housing between an extended position wherein said outer bolt end projects beyond one end of said housing for latching engagement with a keeper plate on the door jamb to latch the door closed and a retracted position wherein said outer bolt end is disposed to clear the keeper plate and release the door for opening, spring means urging said bolt to extended position, a rotatable handle shaft extending transversely of said housing, means connecting said shaft and bolt for retraction oF the bolt by shaft rotation, and means for selectively releasably locking said bolt in extended position against retraction by a force applied to the outer bolt end comprising a locking member on the outer end of said bolt movable between a retracted position wherein said bolt is freely movable into and from latching engagement with the keeper plate and an extended position wherein the member projects from the bolt for locking engagement behind the keeper plate, and actuating means for effecting selective extension and retraction of said locking member independently of extension and retraction of said bolt in a manner which permits extension and retraction of said bolt while said locking member remains in retracted position and extension and retraction of said locking member while said bolt is in extended position.

2. A door lock according to claim 1, wherein:

said locking member comprises a lock pin slidable in the bolt to and from an extended position wherein one end of the pin projects beyond one side of the bolt for locking engagement behind the keeper plate.

3. A door lock according to claim 1 wherein:

said actuating means comprises means operable by rotation of said handle shaft for retracting said member from locking position.

4. A door lock according to claim 1 wherein:

said actuating means comprises an actuator at one side of said door for moving said locking member to locking position independently of handle shaft rotation, and means operable by handle shaft rotation for effecting retraction of said locking member from locking position.

5. A door lock according to claim 3 wherein:

said locking means includes a catch for releasably latching said locking member in said locking position, and said retracting means operable by handle shaft rotation comprises means for releasing said catch upon shaft rotation, and a spring for retracting said locking member upon release of said catch.

6. A lock for a hinged door comprising:

a housing, a latch bolt having a beveled outer end and movable longitudinally in said housing between an extended position wherein said outer bolt end projects beyond one end of said housing for latching engagement with a keeper plate on the door jamb to latch the door closed and a retracted position wherein said outer bolt end is disposed to clear the keeper plate and release the door for opening, spring means urging said bolt to extended position, a rotatable handle shaft extending transversely of said housing, means connecting said shaft and bolt for retraction of the bolt by shaft rotation, and means for releasably locking said bolt in extended position against retraction by a force applied to the outer bolt end comprising a locking pin slidable in the outer end of said bolt for movement laterally of the bolt between an extended position wherein one end of the pin projects beyond one side of the bolt for locking engagement behind the keeper plate and a retracted position flush with the bolt, a telescoping arm extending longitudinally through the housing and a slot in said bolt and including an outer member fixed to said bolt and an inner member slidably engaging the outer member, whereby said latch bolt and outer arm member are movable in unison relative to said inner arm member in the direction of extension and retraction of the bolt, and said arm and pin are movable in unison in the direction of extension and retraction of the pin relative to the bolt, means supporting said inner arm member in said housing for movement in the latter direction, and means operable on said inner arm member for moving said inner member in the latter direction to position said pin in extended and retracted positions.

7. A door lock according to claim 6 wherein:

said means operable on said arm comprises a spring for urging said arm in a direction to retract said pin, an actuator for moving said arm in a direction to extend said pin against the pressure of the latter Spring, a catch for latching said arm in a position wherein said pin is extended, and means for releasing said catch.

8. A door lock according to claim 7 wherein:

said catch releasing means is operable by handle shaft rotation.

9. A door lock according to claim 8 wherein:

said means connecting said handle shaft and bolt comprises a slide frame in and movable longitudinally of said housing, means connecting said latch bolt and frame for retraction of said bolt relative to said frame by an inward force on the outer end of said bolt and retraction of said bolt with said frame by an inward force on said frame, and means on said handle shaft engageable with said frame for retracting said frame and bolt by shaft rotation. said catch is engageable with said frame to latch said lock pin in extended position, and said catch releasing means comprises means for effecting relative longitudinal movement of said arm and frame by handle rotation to release said catch from said frame.

10. In combination:

a door hinged within a door opening for swinging to and from a closed position wherein the outer door edge is disposed in close confronting relation to a door jamb, a keeper plate mounted on said jamb, a door lock mounted on said door along said door edge including a latch bolt having a beveled outer end and movable longitudinally between an extended position wherein said outer bolt end projects beyond said door edge for latching engagement with said keeper plate when said door is closed and a retracted position wherein said outer bolt end clears said keeper plate to permit opening the door, spring means for urging said bolt to extended position, means including rotatable door handles for retracting said bolt against spring pressure by handle rotation, and means for selectively releasably locking said bolt in extended position comprising a locking member on the outer end of said bolt movable between a retracted position wherein said bolt is freely movable into and from latching engagement with the keeper plate and an extended position wherein the member projects from the bolt for locking engagement behind the keeper plate, and actuating means for effecting selective extension and retraction of said locking member independently of extension and retraction of said bolt in a manner which permits extension and retraction of said bolt while said locking member remains in retracted position and extension while said bolt is in extended position.

11. The combination according to claim 10 wherein:

said actuating means comprises an actuator at one side of said door for moving said locking member to locking position independently of door handle rotation, and means operable by door handle rotation for effecting retraction of said locking member from locking position.