Door lock

Details Door lock Door lock

2002-06-14

2004-02-10

Swann, J. J. (Department: 3677)

Closure fasteners

Bolt casings

C292S001500, C292SDIG006, C292SDIG006

Reexamination Certificate

active

06688660

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a door lock and, more particularly, to a door lock which can be assembled smoothly and correctly.
2. Description of Related Art
As shown in
FIG. 1
, there is a door lock that includes a tubular casing
90
having a front end-plat
901
covered with a panel
900
, for the purpose of receiving a bolt
91
, a linking piece
92
, a trigger
93
and a tumbler
94
therein.
The bolt
91
is connected to the linking piece
92
, which is in turn connected to a slider
97
by a clip ring
96
. The slider
97
has two pairs of opposite cogs
971
,
972
, with each pair being adapted to mesh with paws
981
of an annular follower
98
rotatably positioned in aligned holes
991
of a rear cover
99
. The rear cover
99
can be moved, relative to opposite guides
90
a
,
90
b
, to such positions that the paws
981
of the follower
98
may mesh with the cogs
971
or cogs
972
. When the follower
98
is turned, the paws
981
push the cogs
971
,
972
, so as to move the slider
97
and hence the bolt
91
backward. The bolt
91
will return by the action of compressed springs
95
immediately after the follower
98
is released.
In the conventional door lock, it is the panel
900
that defines a furthest or extended position for the bolt
91
. When the lock is being assembled, the panel
900
must be held on the front end-plate
901
, such as with rubber bands, to confine the spring-loaded bolt
91
and trigger
93
in the casing
90
before the panel
900
is riveted to the plate
901
. If the front panel
900
is separated undesirably from the front end-plate
901
, the bolt
91
and then the trigger
93
will move further forward.
The tumbler
94
is then turned by the action of the spring
95
and its hooked front end
941
will not be pressed against a protrusion
931
of the trigger
93
but be moved to the back of the protrusion
931
instead, thus blocking the way the trigger
93
and the bolt
91
may be moved back. The door lock is useless unless it is dismantled and the assembling process is repeated.
In addition, it is usual to find that the annular follower
98
is placed so incorrectly that one of its paws
981
projects outward from the cogs
971
,
972
of the slider
97
, as shown in FIG.
2
. The non-rotatable follower
98
results in a useless lock.
OBJECT OF THE INVENTION
The object of the present invention is to provide a door lock which can be assembled smoothly.
Another object of the present invention is to provide a door lock which can be assembled correctly.
SUMMARY OF THE INVENTION
An improved door lock includes a tubular casing that has a front end-plate covered with a front panel in order to receive and confine a bolt, a linking piece, a spring-loaded trigger and a tumbler in the casing. The bolt is movable in the tubular casing between an extended position and a retracted position, and is spring-loaded in such a way that it tends to be moved to the extended position. The spring-loaded trigger has a front end normally extended out of the casing, and the tumbler is adapted to retain the bolt in the extended position when the front end of the trigger is depressed while the bolt is moved to the extended position.
Two opposite guides are situated behind the tubular casing and joined together. The guides are formed with respective grooves aligned with each other, with a slider movable between the guides forward and backward. The slider is connected to the bolt through the linking piece and is formed with a first pair of opposite cogs and a second pair of opposite cogs. An annular follower is positioned in place in the groves of the guides and has a pair of paws for selectively pushing the pairs of opposite cogs, thereby moving the slider and hence the bolt backward as the follower is turned.
In the present invention, the slider has a pair of indentations defined therein while one of the guides have a pair of teeth engagable with rear ends of the indentations when the bolt is fully extended. This provides the bolt with an extended position independent from the front panel.
Furthermore, one of the guides is additionally formed with a first pair of opposite stops and a second pair of opposite stops, with the first pair of opposite stops located between the first and second pairs of cogs and the second pair of opposite stops located behind the second pair of cogs when the bolt is in its extended position.
In a preferred embodiment, the slider further has a pair of notches formed at a front end thereof and a clip ring is held both around a heck of the linking piece and in the notches of the slider, so as to connect the slider to the linking piece.
In a highly preferred embodiment, there is a rear cover having a pair of aligned through-holes in which annular follower is rotatably positioned. The rear cover is situated behind the tubular casing in either one of two positions, including a first position in which the paws of the annular follower may push the fist pair of opposite cogs, and a second position in which the paws of the annular follower may push the second pair of opposite cogs.


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