FIELD OF INVENTION
This invention relates to a three layer security lock. The lock is adapted to be
used at all the places, for example, house, shops, stores, garages, bank locker,
jewelry shops etc., where a conventional lock is used for locking purposes.
BACKGROUND OF THE INVENTION
The use of locks is well known in the prior art for locking purposes. Conventional
lock comprises a locking latch adapted to be housed in a lock body. The latch
moves in the locking position and open position by a key in combination of the
spring loaded leavers. Guiding means are provided to guide the movement of the
latch inside the lock body. A back plate is riveted with back portion of the lock
body to cover the body from behind and to protect the above mechanism
disposed in the lock body. The key is inserted in the key hole provided in the lock
body and rotated in clockwise or anticlockwise directions so as to open or close
the lock as and when required.
There are disadvantages associated with the conventional locks. One of the
disadvantages is that the back plate can be broken by inserting a punch in the
key hole and hammering the same by a hammer. Thus the locking latch become
free to move and comes out of the lock body easily when the lock is broke open.
OBJECTS OF THE INVENTION
Therefore, an object of the present invention is to provide a three layer security
lock which obviates the disadvantages associated with the prior art.
Another object of the present invention is to provide a three layer security lock
having additional latches for use as additional locking means and thus prevent
opening of the lock even if the main locking latch of the lock is broken.
Yet another object of the present invention is to provide a three layer security
lock which is easy to operate and the maintenance thereof is easy.
STATEMENT OF THE INVENTION
According to this invention there is provided a three layer security lock
comprising a base plate having a chamber provided therewith being provided to
facilitate securing of the lock with the door, locking mechanism adapted to be
housed in the chamber being provided to extend and retract main locking latch
into locking and unlocking position, additional locking latch adapted to be
engaged with the main locking latch being provided for additional locking
security, a cover plate having a key hole provided therein being provided to cover
the locking mechanism.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Three layer security lock according to a preferred embodiment of the present
invention is herein described and illustrated in the accompanying drawings
wherein;
Fig. 1 illustrates perspective view of a conventional lock.
Fig. 2 illustrates elevation view of a lock of the present invention with cover.
Fig. 3 illustrates elevation view of a lock of the present invention without cover.
Fig. 4 illustrates elevation view of an additional locking latch,
Figs. 5 illustrates elevation view of a main locking latch,
DETAILED DESCRIPTION OF THE INVENTION
A three layer security lock is herein described with numerous specific details so
as to provide a complete understanding of the invention. However these specific
details are exemplary details and should not be treated as the limitation to the
scope of the invention. The invention may be performed with slight modifications.
Throughout this specification the word "comprise" or variations such as
"comprises or comprising", will be understood to imply the inclusions of a stated
element, integer or step, or group of elements, integers or steps, but not the
exclusions of any other element, integer or step or group of elements, integers or
steps.
Referring to the drawings, figures 2 and 3, a three layer security lock of the
present invention is shown. The security lock comprises a base plate 1 for
facilitating securing of the lock with the door of a house, shop, store, garage,
bank locker and / or jewelry shop, etc. A chamber 2 is secured with the base
plate 1 such that to accommodate the locking mechanism in it. A cover plate 3 is
provided at the back of the chamber 2 for covering the locking mechanism. The
cover plate 3 has a projection near its peripheral sides such that to hold and
guide movement of the additional locking latch. The locking mechanism
comprises a plurality of spring loaded leavers (not shown) arranged in such a
manner that upon rotating a key, after inserting it in a key hole 4, in a clockwise
or anticlockwise direction main locking latch 5 moves into locking or unlocking
position to lock or unlock the door with the frame of the door. A key hole 6 (not
shown) is provided in the base plate 1 for facilitating insertion of the key to from
inside of the house so as to open or close the lock.
According to this invention an additional locking latch 7 (see figure 4) is provided
on either sides of the main locking latch 5 such that to be moved with the main
locking latch 5 into open or close / locking position as and when required by the
user of the lock. The additional locking latch 7 comprises an L shaped
component having a long arm 8 and a short arm 9. Engagement means, for
example, grooves 10 are provided at the end of the long arm 9 so as to facilitate
engagement of the additional latch 7 with the corresponding grooves 11 provided
in the main latch 5. A guiding groove 12 is provided in the long arm such that to
hold the L shaped component / leaver in its position and also to guide the
movement of the component / leaver during locking and unlocking operation of
the lock.
During working of the lock, the key is inserted into the key hole 4 and then
rotated into clockwise or anticlockwise direction to extend or retract the main
latch 5 along with the additional latches 7 to close or open the door of a house,
shop, store, etc. with the frame provided to hold the door. The frame is secured
with the wall of the house, shop store, etc. However, when the lock is broken by
a miscreant or thief the main latch 6 becomes free and comes out from its locking
position, but the additional latches 8 remain in its locking position and thus
provide additional security to the house, shop, store, bank lockers, etc.
Certain features of the invention have been described with reference to the
example embodiments. However, the description is not intended to be construed
in a limiting sense. Various modifications of the example embodiments as well as
other embodiments of the invention, which are apparent to the persons skilled in
the art to which the invention pertains, are deemed to lie within the spirit and
scope of the invention.

I CLAIM:
1. Three layer security lock comprising a base plate having a chamber
provided therewith being provided to facilitate securing of the lock with the
door, locking mechanism adapted to be housed in the chamber being
provided to extend and retract main locking latch into locking and
unlocking position, additional locking latch adapted to be engaged with the
main locking latch being provided for additional locking security, a cover
plate having a key hole provided therein being provided to cover the
locking mechanism.
2. The three layer security lock as claimed in claim 1, wherein the cover plate
has a projection provided near its peripheral sides being provided to hold
and guide movement of the additional locking latch.
3. The three layer security lock as claimed in claim 1, wherein additional
locking latch are provided on either sides of the main locking latch.
4. The three layer security lock as claimed in claim 3, wherein additional
locking latch comprises an L shaped components having a long arm and a
short arm.
5. The three layer security lock as claimed in claim 4, wherein long arm of
the additional locking latch has a groove towards its end to hold and guide
movement of the locking latch.
6. The three layer security lock as claimed in claim 4, wherein long arm of
the additional locking latch has grooves at its end to facilitate engagement
of the additional locking latch with the main locking latch.
7. The three layer security lock as claimed in claim 1, wherein the main
locking latch has corresponding grooves provided in middle of it such that
to facilitate engagement of the additional locking latches therewith.
8. The three layer security lock substantially as herein described and
illustrated in the accompanying drawings.