US3800687A

US3800687A - Quick-acting release for a normally locked lid of an emergency smoke duct

Info

Publication number: US3800687A
Authority: US
Inventors: K Nozawa
Original assignee: Ryowa Choon Kogyo KK
Current assignee: Ryowa Choon Kogyo KK
Priority date: 1972-11-28
Filing date: 1972-11-28
Publication date: 1974-04-02
Anticipated expiration: 1991-04-02

Abstract

A lid is so supported at an open end of an emergency smoke duct as to tend gravitationally to turn to an open position. A lock mechanism mounted on the back of the lid for normally holding same in a closed position includes a spring-loaded latch for engagement with a roller supported on an interior surface of the duct. In the event of a fire the latch is caused to move out of engagement with the roller by the manual pull of a chain extending through the lid, whereupon the lid turns by gravitation to its open position to permit the smoke and gases of combustion to escape through the duct. The latch may be made of magnetic material so that it will be automatically moved out of engagement with the roller upon energization of a solenoid.

Description

United States Patent [191 Nozawa 1 Apr.2, 1974 QUICK-ACTING RELEASE FOR A NORMALLY LOCKED LID OF AN EMERGENCY SMOKE DUCT [75] Inventor: Kenji Nozawa, Tokyo, Japan [73] Assignee: Ryowa Choon Kogyo Kabushiki Kaisha, Tokyo, Japan [22] Filed: Nov. 28, 1972 [2|] Appl. No.: 310,140

[52] U.S. Cl 98/42, 49/2, 292/144 [51] Int. Cl E05f 15/20 [58] Field of Search 98/1, 42, 43; 49/2, 386; 292/144 X, 201, 142; 52/1, 200

[56 References Cited UNITED STATES. PATENTS 282,822 8/1883 Willard 98/42 3,383,811

5/1968 Ades 49/394 Xv Primary Examiner-William E. Wayner Attorney, Agent, or FirmGeorge B. Oujevolk [57] ABSTRACT A lid is so supported at an open end of an emergency smoke duct as to tend gravitationally to turn to an open position. A look mechanism mounted on the back of the lid for normally holding same in a closed position includes a spring-loaded latch for engagement with a roller supported on an interior surface of the duct. 1n the event of a tire the latch is caused to move out of engagement with the roller by the manual pull of a chain extending through the lid, whereupon the lid turns by gravitation to its open position to permit the smoke and gases of combustion to escape through the duct. The latch may be made of magnetic material so that it will be automatically moved out of engagement with the roller upon energization of a solenoid.

14 Claims, 12 Drawing Figures PATENIEIJAPR 2 I974 .SHiET 1 [1F 5 FIG. I

36b 0 L38 I FIG. 4

FIG 2 PATENTEDAPR 2mm 3'800 687 sumu nr 5 PATENIEUAPR 2 m4 SHEET 5 [IF 5 FIG. l2

1 QUICK-ACTING RELEASE FOR A NORMALLY LOCKED LID OF AN EMERGENCY SMOKE DUCT v BACKGROUND OF THE INVENTION smoke and harmful gases of combustion when a fire takes place in the building. Even in the early stage of the fire, in which only a narrowly limited portion of the building is actually caught by the flames, the smoke and harmful combustion gases are known to take a heavy toll of its inhabitants.

This damage can be minimized, at least in part, by the provision of emergency smoke ducts communicating the confined spaces of the building with the atmosphere. The emergency-smoke ducts may be operatively associated with a blower or blowers to cause discharge of the smoke and combustion gases from such confined spaces. It is necessary in this kind of smoke ducts that their ends open to the various enclosed spaces of the building be normally closed by lids which are readily openable in the event of a fire. Conventionally, however, no simple and inexpensive means have been provided to facilitate the opening operation of the lids, and they have had to be mostly opened by the sheer manual force of the operator. Where attempts have been made to open the lids from a distant position, bulky and complex mechanisms have been required and, worse yet, their performance have not been absolutely reliable.

SUMMARY OFTHE INVENTION It is, therefore, an object of this invention to provide a simple and inexpensive apparatus for quickly opening a lid closing an open end of an emergency smoke duct to cause discharge of smoke and gases of combustion from enclosed spaces in the event of a fire.

Another object of the invention is to provide an apparatus which minimizes the exercise of a manual force necessary for opening the lid at an open end of an emergency smoke duct, so that the lid is easily openable even from a distant position.

A further object of the invention is to provide an apparatus such that the lid at an open end of an emergency smoke duct is readily openable manually and/or electromagnetically.

A further object of the invention is to provide an apparatus including means for preventing the lid from making oscillatory motion when turned to an open position.

Still a further object of the invention is to provide an apparatus including means whereby the lid, after being once opened, can be easily returned to the initial condition, ready for the next opening operation.

Yet a further object of the invention is to provide an apparatus in which the impact of a dropped weight is utilized to open the lid quickly and efficiently, with little exercise of a manual force.

With these objects in view and the other objects hereinafter made apparent, the invention provides, in a ventilation system including a smoke duct having an end open to an enclosed space and a lid openably closing the open end of the smoke duct, an apparatus for quickly opening the lid in the event of a fire which comprises support means for supporting the lid at the open end of the smoke duct in such a manner that the lid tends gravitationally to turn to an open position. Lock means for normally holding the lid in a closed position includes a latch supported on the back of the lid so as to be movable between a first position where the'latch engages a member supported on an interior surface of the smoke duct to hold the lid in the closed position and a second position where the latch disengages the member to permit the lid to turn gravitationally to the open position, the latch being springloaded toward the first position. In the event of a fire the latch is moved to the second position against the spring load by release means which may be actuated either manually or electromagnetically. In further embodiments of the invention the impact of a dropped weight is utilized to move the latch to the second position.

The features which are believed to be novel and characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its construction and mode of operation, together with the further objects and advantages thereof, will be best understood from the following description of some preferred' embodiments read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view of a first preferred embodiment of the invention showing a lid in a closed position, the view being taken along the plane of line 1-] in FIG. 2;

FIG. 2 is a horizontal sectional view taken along the plane of line II-II in FIG. 1;

FIG. 3 is a view similar to FIG. 1 showing the lid in a closed position;

FIG. 4 is a vertical sectional view of a second preferred embodiment of the invention;

FIG. 5 is a vertical sectional view of a third preferred embodiment of the invention;

FIG. 6 is an enlarged, partly broken away side elevational view showing a weight and other means directly associated therewith in the FIG. 5 embodiment;

FIG. 7 is an enlarged topplan view showing a pin adapted to releasably hold the weight of FIG. 6 in an elevated position;

FIG. 8 is a vertical sectional view of a fourth preferred embodiment of the invention; I

FIG. 9 is an enlarged side elevational view showing some essential parts of the FIG. 8' emobidment in more detail;

FIG. 10 is a horizontal sectional view taken along the plane of line XX in FIG. 9;

FIG. 11 is a horizontal sectional view taken along the plane of line XIXI in FIG. 9; and

FIG. 12 is a perspective view showing an alternative arrangement of a weight and other means directly associated therewith in the FIG. 8 embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and in particular to FIGS. 1 to 3 thereof in order to describe a first preferred embodiment of this invention, a duct of any appropriate cross sectional shape, rectangular in this embodiment, is embedded in a ceiling 102 or like horizontal overhead structures of a building to define a passageway 100 through which smoke and gases of combustion are to be discharged in the event ofa fire. Typically made of sheet iron, the duct 10 is flanged at its lower end 11 to be bolted, as at 101, or otherwise secured to the ceiling 102. An open end 12, FIG. 3, of the duct 10 is normally closed by a lid 20 of corresponding shape which also may be made of sheet iron. This lid 20 is turnably supported at 13 by a rod 21 secured at both ends thereof to the two opposed surfaces of the duct 10 and extending parallel to the other two opposed surfaces thereof. It may be noted that the rod 21 is further so disposed as to divide the lid 20 into two unequal rectangles, as best shown in FIG. 2, with the result that the lid tends gravitationally to turn to its verti cal or open position shown in FIG. 3.

The numeral 30 in FIG. 2 generally indicates a lock mechanism mounted on the larger portion 22 of the lid 20 on one side of the rod 21 for normally holding the lid 20 in its horizontal or closed position. The lock mechanism 30 includes a latch 31 in the form of a rod of iron or like magnetic material extending through the hollow space of a solenod 33. A pair of helical tension springs 32 extend between a stationary member 34 and a movable member 35, the latter member being secured to the left hand end 31a, as seen in FIGS. 1 and 2, of the latch 31, so that the latch is resiliently urged to the right in the same drawings. When the solenoid 33 is energized, as upon depression of a push button switch provided in a suitable position of the building, the latch 31 acting as a plunger will be longitudinally displaced to the left, as indicated by the arrow in FIGS. 1 and 2, in spite of the tensile forces on the springs 32.

A bell crank 36 is swingably supported at its fulcrum 36a by a support 37 fixedly mounted on the lid 20 intermediate between the left hand end 31a of the latch 31 and a bore 23 formed through the lid 20 adjacent to the rod 21. One end36b of this bell crank is linked to the end 31a of the latch 31 by a chain 38, whereas the other end 360 of the bell crank is connected to an elongate chain 40 extending downwardly through the bore 23 of the lid 20 and having a grip 41 at its lower extremity.

Means 50 for releasably engaging the end 31b of the latch 31 when the lid 20 is in its closed position is comprised of a bracket 51 secured to the interior surface of the duct 10 and a roller 52 rotatably supported thereby. When the end 31b of the latch 31 is disengaged from the roller 52, either by the energization of the solenoid 33 or by the manual pull of the chain 40, so that the larger portion 22 of the lid 20 is permitted to turn downwardly together with the lock mechanism 30, the lid 20 will swing to and fro in a pendulum fasion before becoming stationary in its vertical position shown in FIG. 3. This is prevented by means generally indicated by the numeral 60 in FIGS. 1 to 3. The means 60 comprises a first rod 61 and a second rod 62 foldably coupled to each other at 63, the first rod 61 being further tumably coupled at 64 to the interior surface of the duct 10, and the second rod 62 being tumably coupled at 65 to the upper surface of the lid 20.

Secured at 103 to the interior surface of the duct 10 is a microswitch having an actuating member 103a in such a position that its contacts will be held open as long as the lid 20 is in its closed position. The microswitch may be electrically associated with a blower and/or an alarm not shown in the drawings. The aforesaid solenoid 33 may also be electrically associated with a smoke or fire detector of well known construction, not shown, in such a manner that the solenoid will be automatically energized by the smoke or fire detector when same has detected a fire in accordance with the prior art.

The first preferred embodiment of the invention being constructed substantially as hereinbefore described, the solenoid 33 of the lock mechanism 30 will be energized immediately in the event of a fire, either automatically by the smoke or fire detector or manually by the depression of the push button switch. The current-carrying solenoid 33 causes the latch 31 to be longitudinally displaced in the direction of the arrow in FIGS. 1 and 2 in opposition to the tensile forces of the springs 32, so that its end 31b becomes disengaged from the roller 52. The lid 20 is now free to turn clockwise, as indicated by the arrow in FIG. 1, on its fulcrum at 13, thus opening the duct 10 as it attains the position of FIG. 3. The microswitch 103 is operated upon clockwise turn of the lid 20 to actuate the blower adapted to discharge the smoke and combustion gases through the duct 10. The alarm may be set off simultaneously to give audible, and perhaps visual, notice of the fire. It will be needless to say that the blower is connected to an electrical power supply so made that its operation is unaffected by the fire.

It is also possible according to this invention for a person standing immediately below the duct opening 20 to manually open the lid 20. This can be accomplished simply by pulling the chain 40 connected to the end 310 of the latch 31 through the bell crank 36 and the chain 38. The latch 31 will then be moved longitudinally out of engagement with the roller 52. Although the energization of the solenoid 33 and the manual pull of the chain 40 may take place simultaneously, the lid 20 will nevertheless be opened unfailingly because the two operations cause the same motion of the latch 31. Upon clockwise turn of the lid 20, the

rods

61 and 62 become stretched as in FIG. 3 thereby preventing the oscillatory motion of the lid and further securely holding same in its vertical position.

FIG. 4 illustrates another preferred embodiment of the invention, in which the duct 10 extends horizontally so that its lid 20 is held vertically in its closed position. The constructions of the lock mechanism 30 and so forth are exactly as set forth during description of the preceding embodiment of FIGS. 1 to 3. However, since the lid 20 in this second embodiment tends gravitationally to turn counterclockwise, as seen in FIG. 4, due to the weight of the lock mechanism 30 and so forth, one or more springs of suitable type are affixed at 104 to the interior surface of the duct 10 in order to urge the lid 20 in the clockwise direction. Thus, when the latch 31 is moved out of engagement with the roller 52 by any of the means discussed previously, the lid 20 will be duly turned clockwise to its horizontal or open position of FIG. 4 thereby causing the smoke and combustion gases to be discharged through the duct 10 with the aid of the blower.

FIGS. 5 to 7 illustrate still another preferred embodiment of the invention, which includes a lock mechanism 70 mounted on the lid of the duct 10, the lid 20 being turnably supported at the open end of the duct '10 in the manner described previously in connection with the FIGS. 1 to 3 embodiment. The lock mechanism 70 includes a latch 72 in the form of a rod extending substantially parallel to the plane of the lid 20 through a guide 73 of hollow cylindrical shape securely supported on'a stationary mount 71. The latch 72 is yieldably urged to the left, as viewed in FIG. 5, by spring means provided within the hollow cylindrical guide 73, so that its end 72b normally rests on the roller 52 to hold the lid in its horizontal or closed position. It may be noted from FIG. 5 that the bracket 51 rotatably supporting the roller 52 has a sloping surface 53 extending between the roller 52 and the interior surface of the duct 10. Thus, for closing the lid 20 after once opening same, as by way of a performance test which may be conducted periodically, the lid may simply be turned counterclockwise in FIG. 5 because then the latch 72 is caused to retract into the guide 73 as its end 72b moves in sliding contact with the sloping surface 53. Urged by the spring means within the guide 73,

the latch 72 will properly. rests on the roller 52 when the lid 20 has been turned to its horizontal position.

The reference numeral 80 generally designates means adapted to convey an impulsive pull to the latch 72 and hence tomove same out of engagement with the roller 52. The means 80 comprises a support 81 fixedly mounted on the upper surface of the lid 20 and a bell crank or, in this particular embodiment, a lever 82 of triangular shape turnably supported at one of its apices by the support 81. Another apex 82a of the lever 82 is connected to the end 72a of the latch 72 by wire 83, whereas the other apex 82b is connected by wire 84 to a weight 91 of means 90 adapted to produce the impulsive pull to be conveyed to the latch 72 by the means 80.

The means 90 comprises the weight 91 connected to the lever 82 by the wire 84 extending through the bore 23 of the lid 20, a rod 92 extending downwardly from the lower surface of the lid 20 through the weight 91,

and a cotter pin 93 removably inserted into a transverse 7 hole 95 at the lower end of the rod 92 projecting from the bottom of the weight 91 so that the weight is normally held in its elevated position under the lid 20. The weight 91, generally of cylindrical shape, is partly hollowed at 91a to house an extra length of the wire 84 and is further bored at 94 to receive the rod 92 with suitable clearance. The cotter pin 93 is connected to a grip 97 by wire 96 of high tensile strength and low elasticity such for example as'piano wire.

In this third preferred embodiment of the invention, constructed as hereinbefore described, the lid 20 in the normal state is held locked in its closed position as the end 7212 of the latch 72 is caused to rest on the roller 52 by the spring means within the guide 73. The extra length of the wire 84 is then held coiled within the hollow space 91a of the weight 91, and the weight 91 is retained in its elevated position by the cotter pin 93.

When, in this condition, the grip 97 is pulled manually, as indicated by the arrow 0 in FIG. 5, the cotter pin 93 can be disengaged from the rod 92 without any great exercise of force. Thereupon the weight 91 is dropped the full extra length of the wire 84 housed in its hollow space 91a, and the apex 82a of the lever 82 receives the full impact of the dropped weight through the wire 84. Thus impulsively turning to the position indicated by the dot-and-dash lines in FIG. 5, the lever 82 pulls the latch 72 to the right through the wire 83 against the spring means within the guide 73. The lock mechanism being now released, the lid 20 is free to turn counterclockwise, as indicated by the arrows b in FIG. 5, to its vertical or open position shown by the dot-and-dash lines in the same drawing.

It will readily occur to those skilled in the art that the cotter pin 93 can be disengaged from the rod 92 by means of an electromagnetic unit, perhaps energized manually by a push button switch or automatically by a smoke or fire detector.

Illustrated in FIGS. 8 to 11 is a further preferred em bodiment of the invention, in which the duct 10, the lid 20, the means 50 and the lock mechanism 70 are all constructed exactly like their respective counterparts in the FIGS. 5 to 7 embodiment. The means differs from the corresponding means 80 of the FIGS. 5 to 7 embodiment only in that the apex 82b of the triangular lever 82 is coupled to an end a of a member 85, the other end 85b of which member is bifurcated as in FIG. 10 for purposes hereinafter made apparent.

The numeral in FIG. 9 generally designates means for applying an impact load to the lever 82 thereby causing same to impulsively turn clockwise as seen in the drawing and hence to move the latch 72 out of engagement with the roller 52. The makeup of the means 110 is such that a vertical guide rod 111, fixedly supported at its upper end by a stationary member 1 12 secured in a suitable manner to the duct 10, extends with clearance through a central bore 113a of the weight 113 and through the bifurcated end 85b of the member 85. A stop 111a is screw-threadedly affixed to the lower end of the guide rod 111 in order to prevent the detachment of the weight 113. This weight 113 is annularly grooved at l13b adjacent to the upper end thereof, and the portion of the weight above this annular slot is tapered at 1136 as in the drawing.

A horizontal support member 114, having its end 114a bent downwardly, issupported at 114b between the stationary member 112 and the weight 113 and is turnable on the guide rod 111. As seen in both FIGS. 9 and 11, a stop extending parallel to the support member 114 has its end 115a loosely received in the annular lgroove l13b of the weight 113 to releasably retain same in its uppermost position on the guide rod 111. A guide slot 1155 is formed approximately centrally of the stop 115 to loosely receive a projection ll4c extending downwardly from the support member 114, the projection 114a having a flange 114d at its lower end to slidably hold the stop 1 15. The other end 1 15c of the stop 1 15 is slidably inserted into an opening ll4e formed through the downwardly bent free end' 114a of the support member 114 and is further connected by piano wire 118 or the like to a grip l 17, FIG.

8, which may be placed in any suitable position of the building. A helical compression spring is provided at 11 6 to resiliently urge the stop 115 toward the weight 113.

When the grip 117 in this fourth preferred embodiment of the invention is pulled manually, as in the event of a fire, the stop 11'5 moves in the direction of the arrow a in FIG. 8 against the helical compression spring 116. The end 115a of the stop 115 being thus disengaged from the annular groove 113b of the weight 113,

the weight drops on the bifurcated end 85b of the member 85 thereby turning the lever 82 clockwise as viewed in FIGS. 8 and 9. The full impact of the weight 113 which has dropped on the member 85 at an accelerated speed is conveyed to the latch 72 of the lock mechanism 70 through the wire 83, pulling the latch in the direction of the arrow b in FIG. 8. The lid 20 is now free to turn as indicated by the arrows c in the same drawing to its vertical or open position.

Since the stop 115 together with its support member 114 is turnable around the guide rod 111, the grip 117 can be positioned in any direction with respect to the duct 10. Further, since the portion 1130 of the weight 113 above its annular slot 113b is tapered upwardly as shown in FIG. 9, the weight after being once dropped onto the member 85, as for a performance test, may simply be manually moved upwardly of the guide rod 1 11 to be arrested in its uppermost position by the stop 115, because then the stop is caused to retract against the helical compression spring 116 as its end 115a slides over the tapered portion 1136 of the weight 113. The once-opened lid 20 may also be simply turned counterclockwise in FIG. 8 to be closed and locked in position, owing to the provision of the sloping surface 53 as in the FIGS. 5 to 7 embodiment.

It is an additionl advantage that the various means constituting this fourth preferred embodiment of the invention areal] conceiled from the view of the building inhabitants, leaving the appearance of the ceiling substantially unimpaired. While the stop 1.15 is caused to drop the weight 113 upon the member 85 by the manual pull of the grip 117 in the illustrated example, it will be apparent that this can also be done by use of an electromagnetic unit which may be energized manually by a push button switch or automatically by a smoke or fire detector.

FIG. 12 shows a modification of the stop 115 and the means more or less directly associated therewith in the FIGS. 8 to 11 embodiment. A horizontal support member 120 is turnably mounted at one end thereof on the guide rod 111 and includes the portion 114 extending downwardly therefrom to slidably support the stop 1 15. Resiliently urged by a helical compression spring 123 toward the guide rod 111, the stop 115 has its end 122 normally received in the annular groove 113b of the weight 113 to hold same in its uppermost position of the guide rod 111. The other end of the stop 115 is coupled directly to a lever 121 extending through a guide slot 124 formed in the support member 120 adjacent to the free end thereof. The free end of the lever 121 is connected by the wire 118 to the grip 117 shown in FIG. 8.

Thus, when the grip 117 is pulled manually, the lever 121 will be turned clockwise as seen in FIG. 12 through the wire 118 thereby causing the stop 115 to move against the helical compression spring 123 out of engagement with the annular groove 113b of the weight 113. The weight drops upon the bifurcated end of the member 85 shown in FIGS. 8 to 10. Thereafter, the lid 20 closing the open end of the duct as in FIG. 8 will be opened through the procedure discussed previously in connection with the FIGS. 8 to 11 embodiment.

While the embodiments of this invention as disclosed herein are well calculated to accomplish the various explicitly stated and implicitly suggested objects of the invention, many modifications thereof will nevertheless occur to those skilled in the art without departing from the spirit and scope of the appended claims. It is therefore to be clearly understood that all matter contained in the above description or shown in the accompanying drawings is of an illustrative and not a limitative nature.

I claim: Y 1. In a ventilation system including a smoke duct having an end open to a enclosed space, and a lid openably closing said end of the smoke duct, an apparatus for quickly opening said lid in the event of a fire, comprising:

support means for supporting said lid at said end of said smoke duct in such a manner that said lid tends gravitationally to turn to an open position;

lock means for normally holding said lid in a closed position, said lock means comprising a latch supported on the back of said lid so as to be movable between a first position where said latch engages a member supported on an interior surface of said smoke duct to hold 'said lid in theclosed position and a second position where said latch disengages said member to permit said lid to turn gravitationally to the open position, and spring means adapted to normally hold said latch insaid first position; and

release means for moving said latch to said second position against said spring means, said release means being actuable from a distant position within said enclosed space.

2. The apparatus as defined in claim 1, wherein said release means comprises a bell crank turnably mounted on the back of said lid, a first elongate flexible element extending between said latch and one of the arms of said bell crank, and a second elongate flexible element extending from the other arm of said bell crank into said enclosed space through an opening formed in said lid.

3. The apparatus as defined in claim 1, wherein said release means includes a solenoid fixedly supported on the back of said lid, and wherein said latch extends through said solenoid, said latch being made of magnetic material, whereby when said solenoid is energized in the event of a fire said latch is caused to move to said second position against said spring means.

4. The apparatus as defined in claim 1, further including means for limiting the angle through which said lid is permitted to turn to its open position, said means comprising a first rod turnably connected at one end to the interior surface of said smoke duct, and a second rod turnably connected at one end to one end of said lid which is turnable outwardly of said smoke duct, said first and said second rod being interconnected at the other ends so as to be turnable relative to each other.

5. The apparatus as defined in claim 4, further including second spring means tending to urge said one end of said lid outwardly of said smoke duct, said duct being so disposed relative to said enclosed space that said lid is held vertically in its closed position.

6. In a ventilation system including a smoke duct having an end open to an enclosed space, and a lid openably closing said end of the smoke duct, an apparatus for quickly opening said lid in the event of a fire, comprismg:

support means for supporting said lid at said end of said smoke duct in such a manner that said lid tends gravitationally to turn to an open position,

said lid being held horizontally when in a closed position; I

lock means for normally holding said lid in the closed position, said lock means comprising a latch supported on the back of said lid so as to be movable between a first position where said latch engages a member supported on an interior surface of said smoke duct to hold said lid in the closed position and a second position where said latch disengages said member to permit said lid to turn gravitationally to the open position, and spring means adapted to normally hold said latch in said first position; and I impulsive release means for impulsively moving said latch to said second position against said spring means by the impact of a dropped weight, said impulsive release means being actuable from a distant position within said enclosed space.

7. The apparatus as defined in claim 6, wherein said impulsive release means comprises a lever of substantially triangular shape turnably supported at one of its apices on the back of said lid, a first elongate flexible element extending between a second apex of said lever and said latch, a second elongate flexible element extending between a third apex of said lever and said weight through said lid, said second elongate flexible element including an extra length loosely housed in a hollow spacewithin said weight when same is in an elevated position, weight retaining means for releasably retaining said weight in the elevated position, and a third elongate flexible element extending from said weight retaining means to a position within easy reach of an operator, said weight being permitted to drop the full extra length of said second elongate flexible element when said weight retaining means is operated through said third elongate flexible element, thereby causing said latch to move to said second position by the impulsive turn of said lever.

8. The apparatus as defined in claim 7, wherein said weight retaining means comprises a stationary member extending downwardly from the front surface of said lid and loosely received in a first bore formed through said weight when same is in the elevated position, and a pin removably inserted into a second bore formed through the lower end of said stationary member projecting from said first bore to normally retain said weight in the elevated position, said pin being connected to one end of said third elongate flexible element.

9. The apparatus as defined in claim 6, further in- I eluding a sloping surface extending between said member and said interior surface of said smoke 'duct such that said latch moves in sliding contact therewith to its first position when said lid is closed manually after being once' opened.

'weight in an elevated position as determined by said guide means, and a second elongate flexible element extending from said weight retaining means to a position within easy reach of an operator, said weight being permitted to drop substantially on said third apex of said lever as guided by said guide means when said weight retaining means is operated through said second elongate flexible element.

11. The apparatus as defined in claim 10, wherein said weight retaining means comprises a stop supported within said duct so as to be movable between a first position where one end of said stop engages said weight to hold same in the elevated position and a second position where said stop disengages said weight to permit same to drop as guided by said guide means, the other end of said stop being connected to one end of said second elongate flexible element, and spring means adapted to normally hold said stop in its first position.

12. The apparatus as defined in claim 11, wherein said stop is turnable around said weight, and wherein a groove is formed circumferentially of said weight to permit engagement thereof by said one end of said stop in any position around said weight, whereby said second elongate flexible element is permitted to extend in any direction with respect to said weight.

13. The apparatus as defined in claim 12, wherein the portion of said weight above said groove is tapered upwardly whereby said one end of said stop slides over said tapered portion to its first position when said weight'is raised manually to its elevated position after being once dropped.

14. The apparatus as defined in claim 10, wherein said weight retaining means comprises a stop supported 'within said duct so as to be movablebetween a first position where one end of said stop engages said weight to hold same in the elevated position and a second position where said stop disengages said weight to permit same to drop as guided by said guide means, a lever connected to the other end of said stop and to one end of said second elongate flexible element to transmit the motion of the latter to the former, and spring means adapted to normally hold said stop in its first position.

Claims

1. In a ventilation system including a smoke duct having an end open to a enclosed space, and a lid openably closing said end of the smoke duct, an apparatus for quickly opening said lid in the event of a fire, comprising: support means for supporting said lid at said end of said smoke duct in such a manner that said lid tends gravitationally to turn to an open position; lock means for normally holding said lid in a closed position, said lock means comprising a latch supported on the back of said lid so as to be movable between a first position where said latch engages a member supported on an interior surface of said smoke duct to hold said lid in the closed position and a second position where said latch disengages said member to permit said lid to turn gravitationally to the open position, and spring means adapted to normally hold said latch in said first position; and release means for moving said latch to said second position against said spring means, said release means being actuable from a distant position within said enclosed space.

4. The apparatus as defined in claim 1, further including means for limiting the angle through which said lid is permitted to turn to its open position, said means comprising a first rod turnably connected at one end to the interior surace of said smoke duct, and a second rod turnably connected at one end to one end of said lid which is turnable outwardly of said smoke duct, said first and said second rod being interconnected at the other ends so as to be turnable relative to each other.

6. In a ventilation system including a smoke duct having an end open to an enclosed space, and a lid openably closing said end of the smoke duct, an apparatus for quickly opening said lid in the event of a fire, comprising: support means for supporting said lid at said end of said smoke duct in such a manner that said lid tends gravitationally to turn to an open position, said lid being held horizontally when in a closed position; lock means for normally holding said lid in the closed position, said lock means comprising a latch supported on the back of said lid so as to be movable between a first position where said latch engages a member supported on an interior surface of said smoke duct to hold said lid in the closed position and a second position where said latch disengages said member to permit said lid to turn gravitationally to the open position, and spring means adapted to normally hold said latch in said first position; and impulsive release means for impulsively moving said latch to said second position against said spring means by the impact of a dropped weight, said impulsive release means being actuable from a distant position within said enclosed space.

7. The apparatus as defined in claim 6, wherein said impulsive release means comprises a lever of substantially triangular shape turnably supported at one of its apices on the back of said lid, a first elongate flexible element extending between a second apex of said lever and said latch, a second elongate flexible element extending between a third apex of said lever and said weight through said lid, said second elongate flexible element including an extra length loosely housed in a hollow space within said weight when same is in an elevated position, weight retaining means for releasably retaining said weight in the elevated position, and a third elongate flexible element extending from said weight retaining means to a position within easy reach of an operator, said weight being permitted to drop the full extra length of said second elongate flexible element when said weight retaining means is operated through said third elongate flexible element, thereby causing said latch to move to said second position by the impulsive turn of said lever.

9. The apparatus as defined in claim 6, further including a sloping surface extending between said member and said interior surface of said smoke duct such that said latch moves in sliding contact therewith to its first position when said lid is closed manually after being once opened.

10. The apparatus as defined in claim 6, wherein said impulsive release means comprises a lever of substantially triangular shape turnably supported at one of its apices on the back of said lid, a first elongate flexible element extending between a second apex of said lever and said latch, guide means for guiding the motion of said weight such that said weight will drop substantially on a third apex of said lever to cause said latch to move to said second position by the impulsive turn of said lever, weight retaining means for releasably holding said weight in an elevated position as determined by said guide means, and a second elongate flexible element extending from said weight retaining means to a position within easy rEach of an operator, said weight being permitted to drop substantially on said third apex of said lever as guided by said guide means when said weight retaining means is operated through said second elongate flexible element.

13. The apparatus as defined in claim 12, wherein the portion of said weight above said groove is tapered upwardly whereby said one end of said stop slides over said tapered portion to its first position when said weight is raised manually to its elevated position after being once dropped.

14. The apparatus as defined in claim 10, wherein said weight retaining means comprises a stop supported within said duct so as to be movable between a first position where one end of said stop engages said weight to hold same in the elevated position and a second position where said stop disengages said weight to permit same to drop as guided by said guide means, a lever connected to the other end of said stop and to one end of said second elongate flexible element to transmit the motion of the latter to the former, and spring means adapted to normally hold said stop in its first position.