Locks – Special application – For closures
Patent
1980-07-07
1982-12-14
Lyddane, William E.
Locks
Special application
For closures
70 92, 70152, 70489, 292 92, 292DIG23, E05B 5504
Patent
active
043632319
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to door locks and, more particularly, to a door lock having a lock release apparatus operative from the inside of the vehicle.
BACKGROUND ART
Most current cabs, for instance, on tractors for bulldozers and the like, are locked from the outside using a key. The locks are such that they cannot be unlocked or operated from inside the cab when locked.
There are some locks which are key locked on one side and have a mechanism on the other side for unlocking. For example, U.S. Pat. No. 2,682,763, issued to Williams on July 6, 1954, shows a garage door latch which is key locked from the outside but has a slide mechanism on the inside which can be actuated on the inside to release the latch. Also, U.S. Pat. No. 1,908,958, issued to Coffron on May 16, 1933, shows a door latch which can be released from the inside and can have the bolt disconnected from the outside handle so that the outside handle will turn without moving the bolt.
A door lock assembly which is known to have a key lock on the outside and a lever on the inside for operating the assembly is used in some heavy equipment cabs today. This assembly has a lock release lever which extends into the cab and may be manually pivoted back and forth between locked and unlocked positions. The lower body of the lever has a notch in which an ear may be received to lock the outside handle from turning and has a cam surface which causes the lever to pivot to an unlocked position when engaged by a shoulder while the inside handle is turned. However, the slot in the door through which the lever extends is relatively long and is only partially blocked by the lever, the remaining portion being open. Thus, dust and other particles are allowed to get into the lock assembly with a potentially deleterious effect thereon.
The present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, a lock assembly is provided for a vehicle door and door latch structure. The lock assembly is operatively engaged to the latch structure for opening and closing the latch through the use of first and second handles extending from opposite sides of the door. The first handle has a lock ring which is coaxially aligned with a bellcrank and rotatable relative thereto, the bellcrank being attached to the second handle. The lock ring has spaced apart projections, one of which engages a locking plate when the plate is in its locked position, thereby preventing movement of the spaced apart projections and lock ring. The bellcrank may engage the locking plate to move it out of its locked position and is connected to the latch structure so as to operate the latch structure when the second handle is turned. The locking plate is connected by a linkage to a point whereby pivoting of one of the links around that point operates the linkage to move the locking plate between its unlocked and locked positions. The pivoting link is connected to a key lock which extends to the same side of the door as the first handle, permitting operation from that side of the door. The pivoting link is also connected to a third handle projecting from the same side of the door as the second handle, which third handle also operates the linkage to move the locking plate between its locked and unlocked positions.
This door lock enables a latch structure provided for vehicles and the like to be operative from the outside and from the inside. When the door lock is locked so that the latch structure may not be operated from the outside, the door lock can be opened in either of two ways from the inside. First, the third handle which operates the linkage may be turned to operate the linkage which, in turn, moves the locking plate to its unlocked position. Secondly, the second handle can be operated to turn the latch ring which, in turn, engages the locking plate to pivot it to its unlocked position. To lock the door lock from the inside, the third handle may be turned in the opposite direction t
REFERENCES:
patent: 1583079 (1926-05-01), Lurie
patent: 1895594 (1933-01-01), Strandt
patent: 1908958 (1933-05-01), Coffron
patent: 2089146 (1937-08-01), Hurd
patent: 2682763 (1954-07-01), Williams
patent: 3698215 (1972-10-01), Truhon
patent: 4277964 (1981-07-01), Crabb et al.
Caterpillar Tractor Co.
Lyddane William E.
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