US2940377A

US2940377A - Ventilator

Info

Publication number: US2940377A
Application number: US674667A
Authority: US
Inventors: Fred P Darnell; Walter J Skipworth
Original assignee: SWARTWOUT FABRICATORS Inc
Current assignee: CANYON SWI Inc; SWARTWOUT FABRICATORS Inc
Priority date: 1957-07-29
Filing date: 1957-07-29
Publication date: 1960-06-14
Anticipated expiration: 1977-06-14

Description

Jame 34; 1960 F. P. DARNELL ET AL 2,940,377

VENTILATOR Filed July 29, 1957 4 Sheets-Sheet 1 N INVENTOR5 3 a F250 D. DARNELL m;

BY WALTEe J. 5K/Ph/0ETH ATTOENEKS June 14 1960 F. P. DARNELL EI'AL 2,940,377

VENTILATOR 4 Sheets-Sheet 2 Filed July 29, 3.957

INVENTOR5 F250 I? DARNELL A BY Wars/2 d 55 /Ph/0?TH a ATTOENE 7 5 June 14, 1960 F. P. DARNELL EI'AL 2, 0,377

VENTILATOR 4 Sheets-Sheet 3 Filed July 29, 1957 mvsmons. F250 Q DARNELL AND BY MLTEE J. K/Ph/OETH June 14, 1960 F. P. DARNELL EFAL 2,940,377

VENTILATOR Filed July 29, 1957 4 Sheets-Sheet 4 IN V EN TORS.

Q5 F250 l DAENELL w: :1 W avg/guise J. 5 IPh OETI-I United States Patent VENTILATOR Fred P. Darnell, Chesterland, and Walter J. Skipworth, Wicklifie, Ohio, assignors, by mesne assignments, to Swartwout Fabricators, Inc., Kokomo, Ind., a corporation of Indiana Filed July 29, 1957, Ser. No. 674,667

7 Claims. (Cl. 98-86) Our invention relates to roof ventilating apparatus or valves and more particularly to normally closed roof valves, which are adapted to open and vent the interior of the building in response to predetermined changes in conditions within buildings.

The desirability of rapidly and automatically or manually opening large roof areas, upon the outbreak of fire and explosion, for example, has long been recognized, in order to vent the smoke, heat and/or explosive force so as to make the fire visible to the firefighters, to control the temperatures within the building, to free the building from noxious gases and/ or to preserve the building against explosive force.

Various apparatus have been developed to accomplish one or more of these objectives but each has been deficient in some respeot and all have failed to provide the protection and advantages, which the art has wanted and demanded. Further, the widespread adoption of large, relatively low, single story factory buildings has accentuated the need for efiicient, acceptable apparatus of this type, albeit without suggesting or indicating how the desired results could be obtained and what the embodiment of such apparatus should be.

It is a general object of our invention to provide an improved, eiiicient, economically manufactured and used, rugged and substantially foolproof roof ventilator for closing roof openings, which is adapted to open and vent the interior of the building in response to predetermined changes in conditions within the building.

A further object is to provide aroof ventilator, adapted normally to close a roof opening, which opens automatically in response to fire, heat and/or explosion, to vent, inter alia, smoke, heat, gas and/or pressure and which is or may be adapted to be operated manually, either from within the building or from without the building on the roof thereof.

Other objects of our invention are the provision of a single roof ventilator for a roof opening which is adapted to be used both to vent the building under ordinary conditions and to provide emergency ventilating facilities for ventilating the building of smoke, heat, and/or pressure;

and/or pressures; which opens to provide a maximum free exhaust path through which gases, heat, and smoke can escape from the interior to the exterior of the building; which is weatherproof; which when open promotes the eduction of smoke and gases from the building and effectively shields and protects the exhaust flow from wind currents and the like.

These and other objects and advantages of our invention will become apparent from the following description of preferred embodiments thereof, reference being had to the accompanying drawings, in which:

Figure 1 is a perspective view, with one damper open and the other removed, of a roof ventilator embodying a preferred form of our invention.

Figure 2 is a sectional view of the ventilator of Figure 1 taken along the line 2-2 of Figure 1 and showing both dampers in the closed position, in full lines, and in an open position, in dotted lines.

Figure 3 is a broken plan view of the ventilator of Figure l with both dampers removed and certain parts broken away to show the operating mechanism.

Figure 4 is a section viewed along the lines 4-4 of Figure 1 showing the hinge by which the dampers are mounted on the body of the ventilator.

Figure 5 is a perspective view, with certain partsbroken away and others omitted, showing another preferred form of operating mechanism in the ventilator of Figure 1.

Figure 6 is a schematic view showing the mechanism of Figure 5, closed, in full lines, and partly opened, in dotted lines.

Figure 7 is a fragmentary sectional view, on an enlarged scale, showing the means for releasably securing the dampers to the damper actuating means.

A roof ventilator or valve embodying a preferred form of our invention is adapted normally to close a roof opening and is further adapted to give instantaneous and automatic relief to predetermined increases in pressures and temperatures within the building to the end of reducing the deleterious effects which fire, explosion and/or heat accumulations may or do have on the building and its contents, and to be manually operable from Within or without the building to open fully and quickly, either for emergency purposes or as an ordinary roof ventilator,

Further our ventilator is adapted to be weatherproof when closed and to aid and expedite the eduction of gases from Within the building to the exterior thereof, when open, by protecting the path of the educted gases from cross winds and other adverse Wind currents.

Briefly a ventilator embodying a preferred form of our invention, see Figures 1 and 2, comprises a supporting structure indicated generally at 1, having a generally triangular transverse section and supporting a pair of

dampers

3 and 4, respectively, each of which is hinged to the supporting structure 1 and is adapted to be opened, on the one hand, by hinged, powered damper carriers or actuating or operating members indicated generally at 6 and 9 respectively, when the same are released, and on the other hand, independently of the members 6 and 9 when acted upon by a direct lifting force. The members 6 and 9 are adapted to be actuated in response to predetermined changes in conditions within the building and/ or manually by an operator.

More particularly the supporting structure '1 preferably comprises a generally rectangular base 12 formed from corrosion resistant sheet metal and adapted to fit over and be secured or anchored to a curb or other mounting provided on the roof of the building and surrounding an opening therein. The base 12 preferably comprises parallel, elongated sides 13 and =14, preferably having longitudinally extending horizontal or

stepped portions

15 and 16, respectively, and parallel, generally triangularly shaped end pieces 17 and 18. The sides and end pieces are secured together at their respective junctures, as by welding, to form a weatherproof vertical guard about the roof opening. The upper edges of the end'pieces 17 and 18 slant upwardly and inwardly from the upper edges of the respective sides and provide a stop or rest for supporting the

dampers

3 and 4 when the same are in the closed position. A brace 19, conveniently formed from, an angle iron, extends between and interconnects the end pieces 17 and 18 near their apexes and gives structural strength to the upper portions of the ventilator as well as support for the actuating members releasing V 22,. not onlyprovide structural strength for the respec- Ii'vesides and ends, but also are adapted to seat'upon and befastened, by suitable fasteners, not shown, to the curb surrounding the roof opening, to the end that the .entire ventilator is easily and expeditiouslyposrtioned iandsecuredlin place.

The supportingrstructure 1 also preferably includes

angle braces

24 and 25, which are secured to the brace 19 'andthe mounting angles 21 and 22 respectively, and ..a channel brace 27, which is secured to and extends between the lowermost portions of the sides 13 and 15 respectively to provide additional structural strength to and for the ventilator.

'' Each of the

dampers

3 and 4 preferably comprises a generallyconcavo-convex main body portion 28 having an angled bottom flange 36, which overlies and overlaps the upper'edge of the respective sides'13 and 14, and an angled top flange 31, which is adapted to mutually overlap andoverlie or underlie the similar flange of the other damper when the ventilator is closed. The mutually overlapping flanges 31 form a weather-proof peak and further cooperate so that the ventilator functions with equal ,facility and advantage without. regard to which damper- 3 or 4 is closed first or is topmost along the overlap. c

' Additionally, each of the

dampers

3 and 4 is provided with

side flanges

33 and 34, respectively, which extend perpendicular to the body portion 28-thereof and overlie andoverlap the top edge of the adjacent end pieces 17 pletelyaweatherproof the roof opening- The

dampers

3 and 4 are adapted to open and close relative to the ventilator and roof opening and in response to predetermined actuating forces, as will hereinafter more fully appear, and to this end are hinged or pivotally and 18 respectively. Thus the dampers when closed commounted on the supporting structure 1 of the ventilator,

about an axis extending longitudinallyof the ventilator.

prises, in addition to the members -6 and 9, a source of force or power such as torsion springs 47' and 48 together with means to control the power source, such as means to set and meansto release the springs, and means to transmit the releasedjorce and motion to the members 6 and 9 and thereby to the dampers to raise them and open the ventilator.

More particularly and preferably'the damper actuating mechanismincludes a pair of parallel, vertically extending, longitudinally'spaced

brackets

49 and 50, which are secured to the underside of the top brace 19 near the midpoint thereof and which fixedly support a rod or shaft 52 extending therebetween. ,In order that the one end of each

spring

47 and 48 may be fixedly anchored and in order that the tension of the springs may be varied at the discretion of the user, I preferably mount a pair of fixed, thou'gh adjustable,

collars

53 and 55 about the shaft near the opposite ends thereof. 'The

springs

47 and 48 are then disposed about the shaft 52 between the

collars

53 and 55, with one end of spring 47 secured to the collar -53 and one end of the spring 48 secured to the collar 55. The opposite ends of the respective springs are preferably secured to collars 56 and 58, which are rotatably supported on the shaft 52 and which are secured to P'referably and conveniently each damper is pivotally on and secured to the adjacent end piece, 17 for example, and extends longitudinallyoutwardly therefrom, and a conveniently disk or cup-shaped spacing and pivot member 37, which functions to space the end of thedarnper from the ventilator end piece, to brace or support the 1 stud 36 a spaced distance from'the end piece 'andto provide a better and more eflicient pivot surface for the V mounted on the ventilator by suitable engagement be-} or formed integral with crank arms or

damper operator angles

59 and 68, respectively (Figure 2). A washer 61 (Figure 3) may be disposed between the

collars

56 and 58 when, as we prefer, the same are otherwise :adjacent'each other.

Damper operating levers 63 and 64 (Figure 2) are pivotally secured to the crank arms 59 and respectively near the ends thereof remote from the collars 56 and .58 and are in turn pivotally'secured to the damper actuating members 6 and 9 respectively. The

crank arms

59 and 60 function to transmit the force and motion of the

springs

47 and 48 to the members 6 and 9and may if desired be integral extensions of the respective ends of the springs 47'and 48 remote from the

collars

53 and 55.

Preferably eachof the actuating members 6 and 9 comprises a pair of longitudinally spaced, parallel angles or .similar members 66 and 67 (Figure '3), which are rotatably supported or hinged, adjacent the top-of the respective sides of the ventilaton'substantially in longitudinal :aligmnentwith the respective damper hinges, as by being rotatablytmounted on the respective rods or shafts 68, which are in turn mounted on the brace 27 at the upper ends thereof. Each of the actuating members 6 and 9 also preferably includes a cross member :or brace ,69, which lies near or adjacent the brace 19 when the actuating-member is in the down (closed) position and which adds structural strength thereto and maintains the mem- .

bers

66 and 67 in longitudinal alignment.

swinging of the damper. The stud 36 preferably has a shoulder. 39 against which the 'pivot member 37. bears a and by which the. cupped portion of the pivot is properly spaced from the ventilator end piece. The or edge of the pivot member 37 is secured to the adjacent end piece as by rivets 40. The freeend of the stud' projects through and has rotatable engagement with a suitable aperture 41 provided in the adjacent side flange of the damper, 33 for example. Preferably a washer 42 is disposed. about the stud between the member 37 and the side flange and an apertured reinforcing plate 43 is secured to' the side flange and adapted to engage about the stud 36 in the same manner as aperture 41.

Thedamper actuators 6'and 9 are a part of a damper operating or actuating mechanism indicated generally at 46 (Figure l) which is adapted to respond automatically to predetermined conditions within the building or selectively, at the will of the operator, to raise the dampers and open the ventilator., 7 'Briefly (see Figures 2 and'3),the mechanism 46; c

The

springs

47 and 48 exert a torque on the collars i56 .andi58 which tends to rotate the respective collars and-crank

arms

59 and 60,unless the same are secured against rotation, and 'to'extend the arms outwardly in opposite direction (to the right and left, respectively, as viewed in Figure 2),. When so rotated the crank arms, in cooperation with the hinged actuating members 6 and 9, move the levers 63 -and 64 intomutual lengthwise alignment respectively to the 'end that the members 6 and 9 are displaced and moved so as to lie in substantially' vertical planes,i.e., extend upwardly, as viewed, from the respective shafts 68 and as the members 6 and 9 are so rotated and displaced they similarly rotate and displace the

dampers

3 and 4, which they respectively sup port, thereby opening the same.

Thus when-thedampers 3 and 4 are closed the actuating members 6 and 9 are forced down tensioning the

springs

47 and 48 and the

dampers

3 and 4 and actuating members 6 and '9 must be held'closed against the force of the

springs

47 and 48. Therefore the actuating mechanism 46'includes means to secure the dampers and actuating members in the closed position against the force of the-springs. Such means is, adapted. to release the damper actuating mechanism either in response .to manual actuation or automatically in response to predetermined changes within the building and preferably in response to a rise in temperature within the building.

To this end we provide means interconnecting and mutually restraining the crank

arms

59 and 60 against rotative movement and means to sever, release or oppose said restraining means in response to predetermined stimuli.

Such means preferably includes a release lever 70 (Figure 2), at the lower end of one of the crank arms, 60 for example, and a pin 72 at the lower end of the other crank arm. The lever 74 extends transversely of the ventilator and is pivotally secured to the crank arm 60. One end of the lever 70 is disposed adjacent the crank arm 59 and is bent or otherwise provided with a hook, as at 73, which is adapted to engage the pin 72 so as to be able to prevent the

arms

59 and 60 from rotating, under the influence of the

springs

47 and 48, outwardly in opposite directions relative to each other in the manner described above. However, the

springs

47 and 48 acting through the

arms

59 and 60 exert suflicient force, unless opposed, to cause the pin to displace the lever 70 and hook 73 upwardly about the pivotal axis of the lever 70 thereby to release the crank arms and actuating mechanism to open the dampers.

Accordingly our actuating mechanism includes means for releasably opposing the force of the torsion springs to maintain the members 6 and 9 closed as well as means to relieve this opposing force in order to permit the

springs

47 and 48 to operate to raise the members 6 and 9 and open the dampers. To this end the release lever 75 preferably extends about the same distance in both directions from the arm 60 and an upward counter force is exerted on the free end 75, leftward end as viewed in Figure 2, of lever 70 to maintain the hook 73, righthand end of lever 71), as viewed, in engagement with pin 72. This counter force may be opposed manually by pulling down on chain 76, which depends from end 75 of lever 70 and has its free end within the reach of an operator.

Preferably this counter force is exerted by means of a spring 77, which is mounted in a chain or similar member 78, one end of which is secured to the end 75 of the lever 70 and the other end of which is adjustably secured to the brace 19 as by passing through an aperture in the horizontal portion thereof and thence through a bifurcated keeper 79. Thus, by pulling on the chain 78, the operator tensions the spring 77 until a sufficient force is exerted thereby on the lever 70 to oppose the force of the torsion springs 47 and 48 and the force so exerted is maintained on the lever 70 by engaging the tensioned chain in the keeper 79. If desired a link of the chain 78 may be painted or otherwise marked so that the operator need only catch said link in the keeper to insure that the spring 77 is under proper tension.

When, as we prefer, the release means herein described is adapted to respond only to a predetermined high temperature and not to a predetermined increase in pressure, a fusible link 81, having a predetermined melting point, is positioned in the chain 78 between the lever 70 and the brace 19. Thus if and when the temperature within the building and about the link rises to the predetermined degree the link fuses, breaking the chain and disconnecting the force of spring 77 from the lever, thereby permitting the torsion springs 47 and 48 to open the dampers in the manner described above.

Further, the operator may also selectively manually open the dampers from within the building by simply pulling on the chain 76 with a force sufiicient, in combination with the force of the torsion springs 47 and 48, to overcome the force of spring 77 and raise the hook 73 out of engagement with the pin 72 whereupon the dampers open in the manner described above.

Since the

dampers

3 and 4 are hinged independently of the actuating members 6 and 9, the dampers 3 and 4 B may open independently of the actuating members 6 and 9 if a sufiicient upwardly directed force be exerted therein, such as might result from an explosion within the building. In order to predetermine the amount of force necessary to so open the dampers and to provide means whereby the respective dampers and actuating members may function as a' unit when the actuating mechanism is operated, a ventilator embodying a preferred form of our invention preferably includes means for releasably securing the

dampers

3 and 4 to the respective actuating members 6 and 9. Preferably such means comprises a plurality of ball and stud spring fasteners or catches indicated generally at 84, Figure 2, mounted with one member secured to the cross members 69, for example, and the other member secured to the respective dampers so as to be in operable relation with the first member. Conveniently the spring stud 84' of each fastener 84 is mounted on the underside of the respective cross members 69 concentrically with an aperture (Figure 3) provided in the member 69 and the ball 84 of each fastener 84 is mounted on the respective damper and is adapted to engage the stud by passing through the aperture 85. When the pressure within the building increases to a predetermined level it exerts a sufficient force on the dampers to separate the balls 84" from the spring studs 84' and to open the independently hinged dampers While the actuating members 6 and 9 remain in the closed position.

Preferably handles 86 (Figures 1 and 2) are mounted on the upper exterior portions of the dampers so that the same may be opened from above by a person lifting thereon with sufficient force to disengage the spring catches 84 and safety chains 87 having springs 88 therein extend between the

braces

24 and 25 and the respective dampers to restrain the dampers against opening too far.

In use and after installation, the ventilator is set by positioning the crank

arms

59 and 60 and release lever 70 and then pulling on the chain 78 until the proper tension is applied and positioningthe same in the keeper. The dampers, if not already closed, are then slammed shut so that the spring catches 34 engage and the ventila tor is ready for use. The ventilator may then be manually operated and opened as desired and needed by pulling on chain 76 or lifting on the handles 86, or automatically opened in response to a predetermined increased pressure, such as might follow an explosion, acting upon and lifting the dampers, or a predetermined increased temperature, such as might follow a fire, fusing the link 81 and releasing the lever 70. Once opened the dampers are closed and if needed the operating mechanism 46 is reset in the manner set forth and the ventilator is ready for another cycle. Thus it is evident that we have provided a simple, rugged, foolproof and eflicient ventilator or roof valve which accomplishes the objects of our invention and provides complete and rapid emergency venting to and for a building upon which it is mounted as well as having the facility and utility of operation incident to providing discretionary interior and exterior manual actuation.

Another preferred form of actuating mechanism for a ventilator embodying our invention is illustrated in Figure 5. The actuating mechanism disclosed in Figure 5 is adapted to be mounted in a ventilator which, conveniently, is in all respects otherwise similar to the ventilator illustrated in Figures 1 through 4. In this alternate form of actuating mechanism the

brackets

49 and 50, shaft 52, brace 27 and actuating members 6 and '9 are substantially similar to the corresponding'parts of the actuating mechanism shown in Figures 1 through 3 and the torsion springs 47 and 43 provide the force and power necessary to operate the mechanism and open the dampers. The springs '47 and '48 are mounted on the shaft 52 and are similar to the springs '47 and 48 except that one end of each extends substantially radially outwardly or tangential therefrom and from the shaft 52, in

V membersfi and 9 respectively.

r 7 1 t a mannersimilar'to the crank arms 59 and-60., U-shaped elbowflocksfll and 92 are mounted on the respective radiallyfezgteuding ends of the springs '47 and 48fl-in axial extension thereof. Damper operating levers 63' and 64' are pivotally secured to the respective elbow locks 9-1 andj92 and actuating members 6 and 9. Conveniently thejlevers 63' and 64' havea bifurcated outward end which is mounted on apin or shaft 93, which extends between the

respective angles

66 and 67 in order to form a yoke type linkage between levers 63' and 6-4 and .Iniord'e'r to oppose the force of thespn'ngs 47' and 48' and restrain the actuating mechanism against openl 3 of the elbow lockgand :an elongated transverse slot ing the dampers except in response to predetermined changes. in conditions within the buildingupon which the ventilatoris mounted or. at the discretion of the operator 7 we preferably mount a bracket 95 on the cross brace 27' at the center'thereof. Z-type hinges or latches 96 and 97,;re'spectively, are pivotally mounted on the bracket.

95 and extend toward the respective sides'of the ventilatormTh e hinges 196.,and 97 are adapted to engage the respective elbow locks 91 and 92 to restrainthe outward rOtfiIY movement of the radially extending ends of the springs47' and 48 in substantially the same manner 96 and .97 and are properly tensioned by means of the vchain 78?.

105,2in one face of the elbow lock and the free end 100 Off. the torsion spring extends through aperture 1112 and V is bent was to extend through and engage within slot 105.

hole 102 is of slightly larger diameter than the end 190 of the spring and the hole .102 and slot 105 are disposed relative toeach other as to cause an engage mentlatE between the spring and 109 and the base 103 ment with the respective elbow locks by the tension springs 77', which are secured to the respective hinges The chain 78 also includes a fusible link 81 and the' chain 78', springs .77 and link 81 function in substantially the same manner and for the same purpose as the chain '78, spring 77 and fusible link 81 described above. Alteeper (notshown) is provided for engaging the chain 78' and maintaining the tension on the springs 77'. Our alternate form of actuating mechanism is also preferably provided with a branched chain 76 in order that discretionary manual release of the actuating mechanism may beetfected.

Rollers-98 are preferably mounted at the'lower outer corners'of the elbow locks 91 and 92 to facilitate the disengaging of the respective Z hinges and elbow locks upon actuation of the operating mechanism. 7 In ayentilator embodying our invention a greater effective force must be exerted upon the dampers, and thereforethe damper actuating members 6 and 9, to initiate the opening of the dampers than is necessary to complete thedisplacement of thedampers to the fully open posi tionsCI This greater'force is necessary not only because of-the inertia of the closed dampers but also'because the inclined position of the closed dampers causes the weight thereof to act through a longer moment arm (W-1, Figure 6)-.than at any other time during the movement thereof (W-Z, Figure 6, for example) and accordingly greater counterforce is necessary, initially, to initiate movement of the dampers.

. 7 Therefore actuating mechanism embodying this form of our invention preferably also includes means to vary and after movement of the damper is initiated as part of the crankarm i.e. spring end 1%. Thus the moment arm through which the damper initially opposes the of the elbow lock when the damper is closed and the stops ltll engage the elbow lock. Thus the elbow lock and operating lever function as an integral unit, while the damper is initially actuated: by and upon'the release of thefoperating mechanism,'to foreshorten the moment arm as iudicatedbYM-l Figure 6. e lOnce the movement of the damper is initiated, however, the stops 'liti are displaced relative to velbow lock so "asto'disengage the same whereupon the spring end 10!), elbow lock and operating lever 64' take the relativei positions shown, forexample, in dotted lines in Figure 6 and the elbow lock functions as an extension ofthe spring end (crank arm) and the moment arm is the distance M -2 between the torsion spring and the pivot P. It is, of course,'necessary that the pivot P between the elbow lock and the operating lever otherwise be at point P in order that the combined length of the spring end 106, elbow lock' '92. and operating lever 64 (for example) is suflicient, when fully extended, to hold the dampers in the desired fully open position.

The preferred form of the alternate actuating mechanism embodying our invention is adapted to respond to the same or similar'stimulias thefirst described actuat- 'ing;mechanisrn embodying our'invention to open the

dampers

3 and 4 in substantially the same manner as the first described actuating mechanism, except that a rela- 'ofrthe damper operating levers 62' and :64, stops 101,

elbow locks 91 and 92 and spring ends as set forth above. 'Modifications, changes and improvements to the above described and illustrated preferred forms and embodi force of the torsion spring is foreshortened M-l, Figure 6, 1

r from what it is M 2 Figure 6 after movement" of the damper has been initiated.

ments of our invention may occur to those skilledin the without departing from'the spirit and substance of our invention. Accordingly'we' do not wish to be limited in'the scope of our patent to the forms and embodiments of our invention herein described nor in any member inconsistant with the advance by which our invention has promoted the art. 7 i We claim: 7 t

' 1. A roof ventilator comprising a base defining a ventilator opening and adapted to be mounted over a roof opening in a building, a pair of opposed dampers adapted to close saidventilator opening and pivotally mounted on said base for outwardly hinged movement relative to'said ventilator opening about parallel axes, and damper actuating means for actuating said dampers. said damper actuating means including damper actuating members supported on said base with one said damper. actuating member being in operable relation with each said damper, respectively, each said damper actuating 'm'emberbein'g pivotally supported on said base for rotation about an axis extending'parallel with said damper axes, having closed and open positions and engaging said respective damper to open it, said damper actuating means also including torsion spring means carried by said'base, a pair of crank arms operably connected with saidtorsionspringmeans, lever means pivotally con nected to each said crank arm remote from said torsion spring means and pivotally connected to said damper actuating members, respectively, and adapted to transmit motion from said crank arms to said damper actuating members, respectively, said torsion spring means biasing said crank arms for rotation in opposite directions about said torsion spring means and away from each other when said actuating members are in said closed position, means adapted to engage said crank arms, to restrain said crank arms against rotation away from each other, spring means restraining, and biasing said restraining means into engagement with said crank arms, fusible link means in said spring means and responsive to a predetermined temperature to sever said spring means and release said restraining means to permit said crank arms to open said actuating members and dampers, and manual release means for selectively opposing and relieving said spring means to release said restraining means to permit said crank arms to open said actuating members without severing said spring means.

2. The ventilator according to claim 1 in which said restraining means comprises a lever pivotally secured to one said crank arm and releasably engaging the other said crank arm and said spring means acts between said lever and said base to urge said lever into engagement with said other crank arm.

3. A roof ventilator comprising a base defining a ventilator opening and adapted to be mounted over a roof opening in a building, a pair of opposed dampers adapted to close said ventilator opening and pivotally mounted on said base for outwardly hinged movement relative to said ventilator opening about parallel axes, and damper actuating means for actuating said dampers, said damper actuating means including damper actuating members supported on said base with one said damper actuating member being in operable relation with each said damper, respectively, each said damper actuating member being pivotally supported on said base for rotation about an axis extending parallel with said damper axes having closed and open positions and engaging said respective damper to open it, said damper actuating means also including torsion spring means carried by said base, a pair of crank arms operably connected with said torsion spring means, lever means pivotally connected to each said crank arm remote from said torsion spring means and pivotally connected to said damper actuating members, respectively, and adapted to transmit motion from said crank arms to said damper actuating members respectively, said torsion spring means biasing said crank arms for rotation in opposite directions about said torsion spring means and away from each other when said actuating members are closed, latch means carried by said base and engaging said crank arms, respectively, to restrain said crank arms against rotation away from each other, and release means including spring means acting between said base and said respective latch means and biasing said latch means into engagement with said crank arms, respectively, fusible link means responsive to a predetermined temperature to sever said release means to disengage said latch means and release said crank arms to open said actuating members and dampers, and manual release means for selec tively opposing and relieving said spring means to disengage said latch means and release said crank arms to open said actuating members without severing said release means.

4. The ventilator according to claim 3 with means responsive to a predetermined outwardly directed force releasably securing each said damper to the respective damper actuating-member.

5. The ventilator according to claim 3 in which said prises two springs and said release means also includes 1 chain means, each said spring having one end secured to a respective latch means and the other end secured to said chain means, said chain means being adapted to engage said keeper to maintain a tension on said springs and said fusible link means being disposed in said chain means.

7. A roof ventilator comprising a base defining a ventilator opening and adapted to be mounted over a roof opening in a building, a pair of opposed dampers adapted to close said ventilator opening and pivotally mounted on said base for outwardly hinged movement relative to said ventilator opening about parallel axes, and damper actuating means for actuating said dampers, said damper actuating means including damper actuating members supported on said base with one said damper actuating member being in operable relation with each said damper, respectively, each damper actuating member being pivotally supported on said base for rotation about an axis extending parallel with said damper axes, having closed and open positions and engaging said re spective damper to open it; said damper actuating member also including torsion spring means carried by said base, a pair of crank arm means operably connected with said torsion spring means, lever means pivotally connected to each said crank arm means remote from said torsion spring means and pivotally connected to said damper actuating members, respectively, and adapted to transmit motion from said crank arm means to said damper actuating members, respectively, said torsion spring means biasing said crank arm means for rotation in opposite directions about said torsion spring means and away from each other when said actuating members are closed, means restraining said crank arm means against rotational movement away from each other, and release means to relieve said restraining means, said crank arm means comprising elbow lock means mounted on each said crank arm means adjacent the end thereof re-' mote from said torsion spring means for limited pivotal motion relative to said crank arm means in the plane in which said crank arm means rotate, each said lever means being pivotally connected to said elbow lock means, respectively, stop means mounted on each said lever means and adapted to' engage said elbow lock means respectively nearer said torsion spring means than said pivotal connection between said lever means and said elbow lock means and pivotally displacing the adjacent portion of said elbow lock means to engage said crank arm means nearer said torsion spring means than said pivot between said elbow lock means and said lever means when said damper actuating member is in a closed position.

References Cited in the file of this patent UNITED STATES PATENTS 950,839 Chadwick Mar. 1, 1910 1,090,389 French et a1. Mar. 17, 1914 1,380,207 Hogstrom May 31, 1921 1,887,484 Walton Nov. 8, 1932 2,551,004 Johnson May 1, 1951 2,766,859 Urquhart Oct. 16, 1956 2,814,979 Johnson Dec. 3, 1957 2,825,275 Gerlitz Mar. 4, 1958 FOREIGN PATENTS 579,572 Great Britain Aug. 8, 1946