Closure fasteners – Bolts – Emergency operating means
Reexamination Certificate
2002-07-09
2003-09-16
Miller, William L. (Department: 3677)
Closure fasteners
Bolts
Emergency operating means
C070S275000, C292S021000, C292S092000, C292SDIG006
Reexamination Certificate
active
06619704
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an emergent unlatching mechanism, simply attached to the interior of the fire door latch without any modification made to the designed structure of the fire door, the fireman uses the ejected water from the hydrant to open the fire door and enter the fire area in time for swift fire fighting.
BACKGROUND OF THE INVENTION
Generally, the fire door is formed to be filled with the fire insulation material in an effort to isolate the heat and thick smoke if there is a fire and to gain the first opportunity of escape. The fire door is an important part of the fire protection; it is designed for easy open to the escape and easy close for the fire separation. As shown in
FIGS. 1 through 4
, it is the latch member popularly employed on the fire door. It mainly comprises a latch assembly
20
, a casing
21
in an inverted U form, a base plate
22
and a chamber to accommodate the latch tongue
24
, arm
26
and swivel seat
28
. A spring
25
with spring leg
251
is hung on an axle
23
, which is fastened on the casing
21
. The spring leg
251
of the spring
25
extends into a catch indent
241
at the lower end of the latch tongue
24
so as to keep the latch
24
always extend out of the casing
21
in up latch position. The latch tongue
24
has a presser
242
at it upper part. The arm
26
has a lug
261
in the center to be fixed with an axle
27
to the casing
21
. The arm
26
has at the front end an upper arm
262
and the lower arm
263
. The upper arm
262
supports the presser
242
of the latch tongue
24
, and the lower arm
263
leans closely on a propeller
281
on the rotary seat
28
. The arm
26
has a pressure wheel
264
at the rear end. The rotary seat
28
is fastened on the base plate
22
and has an inclined semicircular propeller
281
. Now look at
FIG. 4
, When a downward vertical pressure is applied to the pressure wheel
264
of the arm
26
, the arm produce a leverage along the axle
27
, the lower arm
262
will push upward the presser
242
of the latch tongue
24
, forcing the latch
24
turning along the axle
23
and entering the chamber of casing
22
to be in the down latch position. When the key blade
41
of the door key
40
is inserted the key grove
282
on the rotary seat
28
, and is turned rightward so as to turn the propeller
281
of the rotary seat
28
, which will displace the lower arm
263
and form an upward vertical pressure applied to the arm
26
, so the upper arm
262
will push the presser
242
and eventually the latch tongue
24
moves inward in the chamber to be in the down latch position. As shown in
FIG. 1
, the base plate
22
of the latch assembly
20
is fixed on the surface of the fire door
10
, and the pressing board
31
of the handle assembly
30
is also fastened to the surface of the fire door
10
. The latch assembly
20
is disposed in the front end in which the pressure wheel
264
of the arm
26
in the latch assembly is situated to contact the pressure board
31
of the handle assembly
30
. While the pressure board
31
of the handle assembly
30
is pressed downward, a downward vertical pressure is hereby applied to the pressure wheel
264
and consequently force the latch tongue to enter the chamber of the casing
21
and set in the down latch position, the fire door is allowed to open inward or outward. This action is similar to that of fire door key
40
as the key blade turns the rotary seat
28
, pushing the lower arm
263
of the arm
26
upward, forcing the latch tongue
24
to enter the chamber of the casing
21
in the down latch position and release the fire door
10
.
It is apparent that the latch assembly now used on the fire door
10
presents the fireman to enter the fire area behind the fire door
10
unless he has the fire door key in his hand. However, in most cases, the fire door key is stored under good custody, not always hanging on the fire door
10
. If there is a fire, three is no way for the fireman to look for key first, the only compulsory tool he could employ is the torch cut to cut the fire door
10
open for fire fighting.
The inventor has deeply understood the setback the fireman faces to break through the fire door in the first place when a fire takes place and has devoted great efforts for years to the improvement of the latch assembly of the fire door and finally come up an emergent unlatching mechanism which can be easily opened with the water ejection from the fire hydrant and catch the first time to process the fire fighting.
SUMMARY OF THE INVENTION
The main object of the invention is provide an emergent unlatching mechanism to employed in the chamber of the latch assembly on the fire door. It consists of a guide tube with one end situated directly under the upper arm and other end linked to a connecting tube fastened on the fore door. While the high pressure fire fighting water enters the guide tube and the connecting tube as well, and push the upper arm upward which in turn forces the latch tongue entering the chamber of the casing to be in the down latch position, opening the fire door permits the fireman to rush into the fire area to process the fire fighting operation at fast step.
Another object of the invention is to provide an emergent unlatching mechanism for the fire door latch assembly in which the guide tube and the connecting tube have at least a bend for preventing the fire door form being opened by a slender round rod.
The technical features and performance are best explained by the aid of embodiment illustrated in the drawings.
REFERENCES:
patent: 4203622 (1980-05-01), Cook et al.
patent: 4428606 (1984-01-01), Proffer
patent: 4465311 (1984-08-01), Austin
patent: 4540208 (1985-09-01), Logan et al.
patent: 4709950 (1987-12-01), Zortman
patent: 4747629 (1988-05-01), Miller
patent: 2002/0033606 (2002-03-01), Kimoto et al.
patent: 5252799 (1977-04-01), None
patent: 52052798 (1977-04-01), None
Lugo Carlos
Miller William L.
Rabin & Berdo P.C.
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