Note: Descriptions are shown in the official language in which they were submitted.
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LATCH STRUCTURE OF A FIRE DOOR LOCK
FIELD OF THE INVENTION
The present invention is generally relating to a latch structure of a fire
door lock, more particularly to the latch structure of the fire door lock with
fireproof and burglarproof functions.
BACKGROUND OF THE INVENTION
Taiwan patent publication No. 568160 disclosed "structure of fireproof
doors" is relevant to a fire door lock. Two latch bolts are disposed at an
upper end and a lower end of a fire door separately, and the latch bolts can
be blocked by two stoppers disposed at a door frame therefore forming a
lock state. Usually, the blocked latch bolts departs from the stoppers and
leads to an unlock state via actuation of a main lock. Other patents like U.S.
patent number 2,762,642, 4,875,722, 5,464,259, 6,009,732 and 7,070,210
disclosed alternative designs of the fireproof door lock or of the exit door
lock.
With reference to Fig. 1, a fire door lock comprises a latch structure 20
disposed at a fire door 10 and a stopper 40 disposed at a door frame 30.
The latch structure 20 comprises at least a lock base 21 and a latch tongue 22
having a blocking surface 23 and a restraining surface 24 opposite to the
blocking surface 23. The latch tongue 22 is swingably disposed at the lock
base 21. Once the latch structure 20 and the stopper 40 are situated in a
lock state, the blocking surface 23 of the latch bolt 22 may contact against
the stopper 40 to prevent the fire door 10 from being opened. Once the
latch structure 20 and the stopper 40 are situated in an unlock state, the
latch
bolt 22 is actuated by a main lock (not shown in Figs.) to shrink into the
lock
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base 21. At this time, the latch bolt 22 is not blocked by the stopper 40 to
enable the fire door 10 to be opened. With reference to Fig. 2, when the
state of the fire door 10 is switched from the unlock state to the lock state,
the latch tongue 22 can not be actuated by the main lock to enable the latch
tongue 22 to still protrude from the lock base 21. In this moment, the latch
bolt 22 must pass through the stopper 40 to form a lock state. Generally,
the fire door 10 is actuated by a door closer (not shown in Figs.), once the
thrust of the door closer for driving the fire door 10 is insufficient, the
stopper 40 contacts against the restraining surface 24, and eventually an
unlock situation is formed between the latch structure 20 and the stopper 40.
Therefore, the fireproof and burglarproof functions of the fire door 10 will
be all lost via incapability of closing the fire door 10.
Besides, referring to Fig. 1, by using appropriate tools, the latch bolt 22
of the latch structure 20 can be easily pushed and shrunk into the lock base
21 by a thief to form an unlock state between the latch structure 20 and the
stopper 40. Therefore, the burglarproof function will be lost.
With reference to Fig. 2, the latch bolt 20 disposed at the fire door 10
merely blocks the stopper 40 disposed at the door frame 30, once a fire
. occurred, the fire would burn and deform the door frame 30 or the fire
door
10. Accordingly, the stopper 40 can not block the latch bolt 20 of the latch
40 disposed at deformed fire door 10. Therefore, the fireproof function of
the fire door 10 would be all lost.
SUMMARY
The primary object of the present invention is to provide a latch
structure of a fire door lock comprising a lock base, a latch unit, a coupling
set and a fixing rod. The lock base comprises a bottom portion, a first
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,
lateral portion, a second lateral portion and an accommodating slot defined
by the bottom portion, the first lateral portion and the second lateral
portion.
The latch unit comprises a latch bolt, an actuating member, a penetrating
bolt and a combining pin, and mentioned latch unit is swingably disposed at
the accommodating slot of the lock base. The latch bolt can be driven by
the combining pin between a projected position and a retracted position in
response to the movement of the actuating member. The combining pin is
configured to move along a path. The liking set is disposed at the
accommodating slot and comprises at least one first coupling member, and
the combining pin is pivotally connected with the first coupling member and
the latch unit. The fixing rod comprises a first fixing end and a second
fixing end, wherein the first fixing end and the second fixing end are fixed
at
the first lateral portion and the second lateral portion respectively. When
the latch bolt moves to the projected position, the penetrating bolt and the
fixing rod may define a line which crosses the path, wherein the combining
pin moves toward the bottom portion of the lock base along the path and
stops moving until the combining pin crosses the line.
Accordingly, when a thief tends to push the latch bolt into the lock base
by using tools, the latch bolt can not shrink into the latch base by means of
position limitation of the combining pin. Therefore, the burglarproof
function can be effectively achieved in this invention.
The secondary object of this invention is to provide a latch structure of
the fire door lock further comprising a blocking member and an elastic
member, wherein the blocking member comprises a blocking plate, a
contacting portion and a restraining slot positioned beneath the blocking
plate. The elastic member comprises a first end, and the contacting portion
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of the blocking member can be pressed by the first end. The restraining
slot is corresponded to the latch bolt. Once the fire door is situated in an
unlock state, the latch bolt can be shrunk into the lock base to enable the
blocking member to swing toward the latch bolt via elasticity of the elastic
member, and the latch bolt is accommodated into the restraining slot of the
blocking member. At last, the blocking plate of the blocking member
contacts against a restraining surface of the latch bolt. When the state of
the fire door is switched from an unlock state into the lock state, the latch
bolt may pass through a stopper disposed at a door frame rather than being
blocked by the stopper. Eventually, the blocking member may prop against
the stopper to enable the latch bolt to depart from the restraining slot of
the
blocking member and protrude from the lock base to from a lock state.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram illustrating a lock state formed between a
latch bolt of a conventional fire door lock and a stopper.
FIG. 2 is a schematic diagram illustrating an unlock situation formed
between the latch bolt of the conventional fire door lock and the stopper.
FIG 3 is a perspective assembly view illustrating a latch structure of a
fire door lock in accordance with a preferred embodiment of the present
invention.
FIG 4 is a perspective exploded view illustrating the latch structure of
the fire door lock in accordance with a preferred embodiment of the present
invention.
FIG 5 is an upward view illustrating the latch structure of the fire door
lock in accordance with a preferred embodiment of the present invention.
FIG 6 is a schematic diagram illustrating a lock state formed between
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the latch structure of the fire door lock and the stopper in accordance with a
preferred embodiment of the present invention.
FIG 7 is a perspective schematic diagram illustrating a lock state
formed between the latch structure of the fire door lock and the stopper in
accordance with a preferred embodiment of the present invention.
FIG 8 is a perspective section view illustrating a lock state formed
between the latch structure of the fire door lock and the stopper in
accordance with a preferred embodiment of the present invention.
FIG. 9 is a schematic diagram illustrating a lock state formed between
the latch structure of the fire door lock and the stopper in accordance with
another preferred embodiment of the present invention.
FIG 10 is a section view illustrating a lock state formed between the
stopper and the latch structure disposed at deformed fire door in accordance
with a preferred embodiment of the present invention.
FIG 11 is a schematic dia gram illustrating an unlock state formed
between the latch structure of the fire door lock and the stopper in
accordance with a preferred embodiment of the present invention.
FIG 12 is a perspective schematic diagram illustrating an unlock state
formed between the latch structure of the fire door lock and the stopper in
accordance with a preferred embodiment of the present invention.
FIG 13 is a perspective section view illustrating an unlock state formed
between the latch structure of the fire door lock and the stopper in
accordance with a preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
With reference to Figs. 3, 4, 5 and 6, a latch structure of a fire door lock
100 disposed at a fire door 200 in accordance with a preferred embodiment
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of the present invention comprises a lock base 110, a latch unit 120, a
blocking member 130, a pair of male and female means B, C, an elastic
member 140, a coupling set 150 and a fixing rod 160. The lock base 110
comprises a bottom portion 111, a first lateral portion 112, a second lateral
portion 113 and an accommodating slot 114 defined by the bottom portion
111, the first lateral portion 112 and the second lateral portion 113, wherein
the bottom portion 111 of the lock base 110 is disposed at the fire door 200.
The first lateral portion 112 comprises a first sliding slot 112a and a first
installing hole 112c, the second lateral portion 113 comprises a second
sliding slot 113a and a second installing hole 113c, the fixing rod 160
comprises a first fixing end 161 and a second fixing end 162, and the first
fixing end 161 and the second fixing end 162 of the fixing rod 160 can be
inserted into the first installing hole 112c and the second installing hole
113c
respectively. The first sliding slot 112a and the second sliding slot 113a are
formed into a concave arc A, wherein each of the concave arcs A is oriented
to the first installing hole 112c and the second installing hole 113c
separately.
The first sliding slot 112a comprises a first recess 112b, the second sliding
slot 113a comprises a second recess 113b, and the first recess 112b and the
second recess 113b are adjacent to the bottom portion 111 of the lock base
110.
The latch unit 120 comprises a latch bolt 121, a combining pin 122, at
least one actuating member 123 and a penetrating bolt 124. In this
embodiment, the quantity of mentioned actuating member 123 is two, and
the penetrating bolt 124 is penetrated through the actuating members 123
and the latch bolt 121 to form a mutual link between the actuating members
123 and the latch bolt 121. The latch 121 comprises a blocking surface
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121a and a restraining surface 121b in communication with the blocking
surface 121a. The combining pin 122 comprises a first end portion 122a
and a second end portion 122b, and the first end portion 122a and the second
end portion 122b are slidably disposed at the first sliding slot 112a and the
second sliding slot 113a respectively. The latch bolt 121 is swingably
disposed at the accommodating slot 114 of the lock base 110. The latch
bolt 121 can be driven by the combining pin 122 between a projected
position and a retracted position in response to the movement of the
actuating member 123. When the fire door 200 is situated in a lock state,
the latch bolt 121 is located at the projected position (please see Figs. 6
and
9). Oppositely, when the fire door 200 is situated in an unlock state, the
latch bolt 121 is located at the retracted position (please see Fig. 10). The
blocking member 130 is swingably disposed at the accommodating slot 114
of the lock base 110 and comprises a blocking plate 131, a restraining slot
132 located beneath the blocking plate 131, a first lateral plate 133
protruded
from the blocking plate 131 and a second lateral plate 134 opposite to the
first lateral plate 133. The first lateral plate 133 comprises a first
restraining recess 133a, the second lateral plate 134 comprises a second
restraining recess 134a, and the combining pin 122 can be restrained within
the first restraining recess 133a and the second restraining recess 134a.
In this embodiment, the length of the blocking plate 131 is smaller than
that of the first and the second lateral plates 133, 134 to lead an incomplete
connection between the blocking plate 131, the first lateral plate 133 and the
second lateral plate 134 therefore forming the restraining slot 132. The
restraining slot 132 is corresponded to the latch bolt 121. The latch bolt
121 may be blocked by the blocking plate 131 of the blocking member 130
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and accommodated into the restraining slot 132. The blocking member 130
can be actuated by elasticity of the elastic member 140 disposed at the
accommodating slot 114 of the lock base 110.
In this embodiment, the elastic member 140 can be a torsion spring, the
torsion spring comprises a first end 141, a second end 142 and a barrel
portion 143 disposed around the fixing rod 160. The blocking member 130
further comprises a contacting portion 135 which is pressed by the first end
141 of the elastic member to enable the blocking member 130 to swing
toward the latch bolt 121. Besides, the contacting portion 135 can be a
cantilever protruded from the first lateral plate 133 and faces toward the
second lateral plate 134. In this embodiment, the contacting portion 135
comprises a trench 135a, the first end 141 of the elastic member 140 is
coupled to the trench 135a, and the second end 42 of the elastic member 140
is coupled to the combining pin 122 of the latch unit 120.
The coupling set 150 having at least one first coupling member 151 is
disposed at the accommodating slot 114 and pivotally connected with the
latch unit 120. The combining pin 122 is pivotally connected with the first
coupling member 151 and the latch unit 120. In this embodiment, the
quantity of mentioned first coupling member 151 is two, the actuating
members 123 are located between the first coupling members 151, and the
first coupling members 151 are located between the first and the second
lateral plates 133, 134. The combining pin 122 is penetrated through the
actuating members 123 and the first coupling members 151 to form a mutual
link between the actuating members 123 and the first coupling members
151.
When the latch bolt 121 extends outwardly from the lock base 110, the
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first end portion 122a of the combining pin 122 can be restrained within the
first recess 112b of the first sliding slot 112a, and the second end portion
122b can be restrained within the second recess 113b of the second sliding
slot 113a. Therefore, the combining pin 122 can be effectively restrained
within mentioned sliding slots to prevent from separation with the lock base
110. Meanwhile, the first end portion 122a of the combining pin 122 can
be restrained within the first restraining recess 133a of the first lateral
plate
133 and the second end portion 122b can be restrained within the second
restraining recess 134a of the second lateral plate 134 to prevent the latch
bolt 121 from being pushed into the lock base 110 by external force to lead
an unlock situation.
The fixing rod 160 is pivotally connected with the blocking member
130 and the first coupling members 151 of the coupling set 150, and the first
and the second lateral plates 133, 134 of the blocking member 130 are
located between the first coupling members 151. The first fixing end 161
and the second fixing end 162 are fixed at the first lateral portion 112 and
the second lateral portion 113 of the lock base 110 respectively. The fixing
rod 160 is penetrated through the first lateral plate 133, the first coupling
members 151 and the second lateral plate 134 to form a mutual linked
relationship between the first lateral plate 133, the first coupling members
151 and the second lateral plate 134. In this embodiment, the latch
structure of the fire door lock 100 further comprises a coupling rod 170, and
one end of the coupling rod 170 is pivotally connected with the coupling set
150.
With reference to Figs. 3, 4 and 5 again, the latch structure of the fire
door lock 100 further comprises a pivoting rod 180, and the coupling set 150
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further comprises a second coupling member 152. The first coupling
member 151 is pivotally connected with the second coupling member 152,
and the pivoting rod 180 is pivotally connected with the second coupling
member 152 and the coupling rod 170. Besides, the first lateral portion 112
and the second lateral portion 113 of the lock base 110 comprise a
longitudinal sliding slot 115 respectively. The pivoting rod 180 comprises
two terminals 181, and each of the terminals 181 can be slidably disposed at
each of the longitudinal sliding slots 115.
Referring to Figs. 4, 6 and 7, a lock state is formed between the latch
structure of the fire door lock 100 and a stopper 400 disposed at a door
frame 300, wherein mentioned latch structure of the fire door lock 100 can
be fastened by the stopper 400. The blocking member 130 is fastened at
the stopper 400 via the pair of male and female means B, C. The quantity
of mentioned first lateral plate 132 and the male means B are two separately.
In this embodiment, the stopper 400 comprises a rear surface 420 adjacent to
the fire door 200 and a front surface 410 opposite to the rear surface 420,
the
female means C comprises an accommodating portion Cl formed at the rear
surface 420. The lock base 110 further comprises a top portion 116, and
the male means B comprises a fastener B1 formed at the blocking member
130 and protruded to the top portion 116 of the lock base 110. The fastener
B1 can be fastened at the accommodating portion Cl, wherein the fastener
B1 of the male means B and the contacting portion 135 are formed at the
first lateral plate 133. Furthermore, the blocking member 130 is actuated
by elasticity of the elastic member 140 to enable the fastener B1 to fasten
with the stopper 400.
With reference to Figs. 4, 6, 7 and 8, when the combining pin 122 is
CA 02762906 2011-12-28
actuated by the first linking member 151 of the linking set 150, the latch
bolt
121 can be driven by the combining pin 122 simultaneously. Therefore, the
latch bolt 121 of the latch unit 120 is protruded from the lock base 110, and
the stopper 400 is located between the latch bolt 121 and the blocking
member 130. In this embodiment, the blocking surface 121a is utilized for
contacting against the front surface 410 of the stopper 400. Therefore, the
latch bolt 121 can be blocked by the stopper 400 to prevent the fire door 200
from being opened. The combining pin 122 is pivotally connected with the
first coupling members 151 and the actuating members 123 and configured
to move along a path R. The first end portion 122a of the combining pin
122 can be restrained within the first recess 112b, and the second end portion
122b can be restrained within the second recess 113b. When the latch bolt
121 is pressed by external force, a thrust force is generated and tends to
push
the latch bolt 121 into the lock base 110. With reference to Fig. 6, the
penetrating bolt 124 and the fixing rod 160 may define a line L which
crosses the path R. The combining pin 122 slidably moves toward the
bottom portion 111 of the lock base 110 along the path R, and stops moving
until the combining pin 122 passes across the line L defined by the
penetrating bolt 124 and the fixing rod 160, wherein the path R is viewed as
the moving trace of the core of the combining pin 122, and the line L is a
straight line which links the core of the penetrating bolt 124 and the core of
the fixing rod 160. Besides, the combining pin 122 is configured to be
spaced from the line L to the bottom portion 111 when the latch bolt 121 is
located at the projected position. In this moment, the combining pin 122
can not move upwardly along the first sliding slot 112a and the second
sliding slot 113a. However, the first end portion 122a of the combining pin
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122 contacts against the first recess 112b, and the second end portion 122b
contacts against the second recess 113b to enable the combining pin 122 to
stop moving toward the bottom portion 111 of the lock base 110 along with
the first and the second sliding slot 112a, 113a in counterclockwise
direction.
Accordingly, the latch bolt 121 may not be pushed into the lock base 110 via
the actuation of the combining pin 122. The combining pin 122 and the
actuating members 123 supports the latch bolt 121 to prevent the latch bolt
121 from being pushed into the lock base 110 by external force to lead an
unlock situation.
Otherwise, the first end portion 122a of the combining pin 122 may
contact against the first restraining recess 133a of the first lateral plate
133,
and the second end portion 122b may contact against the second restraining
recess 134a of the second lateral plate 134. Therefore, the combining pin
122 can not be actuated by the latch bolt 121 and can not separate from the
first restraining recess 133a and the second restraining recess 134a.
Mentioned design may prevent the latch bolt 121 from being pushed into the
lock base 110 by external force to lead an unlock situation.
In another embodiment with reference to Fig. 9, when the latch bolt 121
moves to the projected position, the combining pin 122 moves toward the
bottom portion 111 of the lock base 110 along the first sliding slot 112a and
the second sliding slot 113a, and the combining pin 122 is configured to be
at a crossing point P where the line L meets the path R when the latch bolt
121 is reached and located at the projected position. When the latch bolt 121
is at the projected position and pressed by external force, the combining pin
122 can not slidably move toward or backward along with the first slot 112a
and the second slot 113a because the external force only acts in the direction
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to the fixing pin 160 ( i.e. the line L) without acting in others directions.
Accordingly, the combining pin 122 only tends to move toward the fixing
pin 160 along the line L, however, the combining pin 122 remains stable
because the walls of the first slot 112a and the second slot 113a block the
combining pin 122 to move further along the line L. Therefore, the latch
bolt 121 can not be pushed into the lock base 110 by linkage of the
combining pin 122 to avoid an unlock situation.
Referring to Figs. 4 and 9, when the latch bolt 121 projects from the
accommodating slot 114 of the lock base 110, an accommodating space S
can be defined between the blocking member 130 and the latch bolt 121, and
the stopper 400 can be fitted inside the accommodating space S to enable the
fastener B1 to fasten with the stopper 400. Firmly fastened relationship
between the stopper 400 and the latch bolt 121 may prevent the stopper 400
from being unable to block the latch bolt 121 via deformed fire door 200 or
deformed door frame 300 under fire condition. Referring to Fig. 10, the
relative position between the latch bolt 121 and the front surface 410 of the
stopper 400 might be changed via deformed fire door 200, but the fastener
B1 is still fastened at the accommodating portion Cl. Accordingly, the
lock state of the fire door 200 can be remained, and the flame will be
restrained by the fire door 200 under fire condition to achieve fireproof
function.
Furthermore, the accommodating portion Cl is formed inside the
stopper 400. When the fastener B1 is fastened at the accommodating
portion Cl, a big contact area between the blocking member 130 and the
accommodating portion Cl is formed to increase overall friction force to
avoid the fastener B1 to be departed from the stopper 400. Therefore, the
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fire door 200 is steadily maintained in the lock state.
When the latch bolt 121 projects from the lock base 110, the combining
pin 122 of the latch unit 120 is positioned far from the contacting portion
132 of the blocking member 130. Besides, for the reason that the
contacting portion 132 of the blocking member 130 is pressed by the first
end 141 and the second end 142 of the elastic member 140 coupled by the
combining pin 122 of the latch unit 120, the elastic member 140 can be
formed into a stretched state. The stretched elastic member 140 may
generate an elasticity to pull the blocking member 130 back to the direction
of the latch bolt 121. Accordingly, the fastener B1 can be firmly fastened
at the accommodating portion Cl to enable the fire door 200 to be firmly
maintained in the lock state.
Figure 11 is a schematic diagram illustrating an unlock state formed
between the latch structure of the fire door lock 100 and the stopper 400.
With reference to Figs. 4, 11, 12 and 13, the pivoting rod 180 can be driven
by the coupling rod 170 to move upwardly along each of the longitudinal
sliding slots 115, in the meantime, the second coupling member 152 of the
coupling set 150 can be driven by the pivoting rod 180 to pivot toward the
bottom portion 111 of the lock base 110. Besides, the first coupling
members 151 is pivotally connected with the second coupling member 152
to enable the first coupling members 151 to swing via the fixing rod 160
serving as a shaft. Due to the interconnection between the combining pin
122, the first coupling members 151 of the coupling set 150 and the
actuating members 123 of the latch unit 120 and the movement limitation of
the combining pin 122 within the first sliding slot 112a and the second
sliding slot 113a, when the combining pin 122 is actuated by the first
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coupling members 151, the combining pin 122 moves outwardly along with
the first sliding slot 112a and the second sliding slot 113a to enable the
first
end portion 122a and the second end portion 122b to depart from the first
recess 112b and the second recess 113b respectively. In the mean time, the
actuating members 123 can be actuated by the combining pin 122, and the
latch bolt 121 can be actuated by the actuating members 123 to enable the
latch bolt 121 to shrink into the lock base 110. Meanwhile, the first end
portion 122a and the second end portion 122b of the combining pin 122 are
departed from the first recess 112b and the second recess 113b respectively
to enable the blocking member 130 to stop being restrained by the
combining pin 122. Furthermore, the blocking member 130 can be
actuated by elasticity of the elastic member 140 to swing via the fixing rod
160 serving as a shaft. Also, the latch bolt 121 is accommodated into the
restraining slot 132 of the blocking member 130, and the blocking plate 131
of the blocking member 130 contacts against the restraining surface 121b of
the latch bolt 121 to prevent the latch bolt 121 from protruding to the lock
base 110. Accordingly, when the state of the fire door 200 is switched from
the unlock state to the lock state, the latch bolt 121 may pass through the
stopper 400 rather than blocked by the stopper 400. T he blocking member
130 may prop against the stopper 400 to enable the latch bolt 121 to depart
from the restraining slot 132 of the blocking member 130, and then the latch
bolt 121 can not be blocked by the blocking member 130. At last, the latch
bolt 121 is protruded from the lock base 110 and enables the stopper 400
located between the latch bolt 121 and the stopper 130 to form a lock state.
In this invention, when the latch structure of the fire door lock 100 is
situated in the lock state, the first end portion 122a and the second end
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portion 122b of the combining pin 122 are restrained within the first recess
112b of the first sliding slot 112a and the second recess 113b of the second
sliding slot 113a respectively. Therefore, the restraining function of the
combining pin 122 is completely achieved. Or, the first end portion 122a
and the second end portion 122b of the combining pin 122 can be restrained
within the first restraining recess 133a of the first lateral plate 133 and
the
second restraining recess 134a of the second lateral plate 134 respectively.
The first end portion 122a of the combining pin 122 contacts against the first
recess 112b or the first restraining recess 133a, and the second end portion
122b contacts against the second recess 113b or the second restraining recess
134a to prevent the latch bolt 121 from being pushed into the lock base 110
by external force to lead an unlock situation. Therefore, the burglarproof
function of the latch structure of the fire door lock 100 can be significantly
raised. Besides, when the fire door 200 is situated in the unlock state, the
latch bolt 121 is shrunk into the lock base 110, and the blocking member 130
is swingable toward the latch bolt 121 via the fixing rod 160 serving as a
shaft. The latch bolt 121 is accommodated into the restraining slot 132 of
the blocking member 130, and the blocking plate 131 of the blocking
member 130 contacts against the restraining surface 121b of the latch bolt
121. When the state of the fire door 200 is switched from the unlock state
to the lock state, owing to the contact between the blocking plate 131of the
blocking member 130 and the restraining surface 121b of the latch bolt 121,
the latch bolt 121 may pass through the stopper 400 easily. When the latch
bolt 121 has passed through the stopper 400, the blocking member 130 may
prop against the stopper 400 to enable the latch bolt 121 to depart from the
restraining slot 132 of the blocking member 130. Eventually, the latch bolt
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. -
121 is protruded from the lock base 110 therefore forming the lock state.
The burglarproof and fireproof functions of the latch structure of the fire
door lock 100 can be completely achieved.
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