US2649728A

US2649728A - Air-moving device

Info

Publication number: US2649728A
Application number: US99680A
Authority: US
Inventors: Buttner Carl Martin
Original assignee: HUNTER FAN AND VENTILATING COM
Current assignee: HUNTER FAN AND VENTILATING COM; HUNTER FAN AND VENTILATING COMPANY Inc
Priority date: 1949-06-17
Filing date: 1949-06-17
Publication date: 1953-08-25
Anticipated expiration: 1970-08-25

Description

Aug 25, 1953 c. M. BUTTNER 2,649,728

AIR MOVING DEVICE Filed June 17, 1949 Patented Aug. 25, 1953 AIR-MOVING DEVICE Carl Martin Buttner, Memphis, Tenn., assignor to Hunter Fanand Ventilating Company, Inc., Memphis, Tenn., a. corporation of New York Application June 17, 1949, Serial N o. 99,680

12 Claims. 1

This invention relates to improvements in airmoving devices. More particularly this invention relates to an improved mechanism for operating the louvers of an air-moving device.

It is therefore an object of the present invention t-o provide an improved operating mechanism for the louvers of an air-moving device.

In the operation of the louvers of an air-moving device, it is desirable to be able to move the louvers to and from open position without necessitating the exercise of dexterity or skill on the part of the operator. Where this is done, children aswell as adults can safely open and yclose the louvers. However, in using some prior louveroperating mechanisms the operator had to align the operating cor-d or chain with a slot and then move that cord or chain into that slot. In other instances the operator of the louver-actuating mechanism had to have'a rather delicatesense of touch because he had to feel out one of a number of possible settings for the louvers. These prior louver-actuating mechanisms are quite workable where the operators have keen vision and have good manual dexterity; but not all potential operators of those mechanisms have those qualifications. Moreover, the louver-actuating mechanisms are frequently disposed over the operators head; requiring the operator to have a good sense of equilibrium as well.

For these various reasons, prior louver-actuating mechanisms for air-moving devices are objectionable. The present invention obviates these objections by providing a simple louver-actuatng mechanism which 4can be operated by even the most unskilled persons. That mechanism responds to a downward pull on its cord "or chain to lock the louvers open, and then responds to a second downward pull on that cord or chain to permit the louvers to close. With such a mechanism there is no need of keen vision, good-dexterity, or stable equilibrium; all that is needed is the desire to actuate the mechanism and a downward pull on the cord or chain. It is therefore an object of the present invention'k to provide a louver-operating mechanism that responds to a downward pull on its cord or chain to lock the louvers open, and that responds to -a second downward pull to permit the louvers to close.

The louver-operating mechanism provided -by the present invention is sturdy and rugged, and it has a spring ybetween the cord or chain and the latching elements. Thus .the mechanism vcan withstand strong forces exerted thereon, andthe spring will yield and limit the size of the forces that can be applied to the operating mechanism. It is therefore an object of the present invention to provide a sturdy and rugged louver-operating mechanism which has a spring between the cord or chain and the latching elements.

The louver-actuating mechanism provided by the .present invention has a movable arm which carries a rotatable ratchet with alternate deep and shallow notches. The alternation of the deep and shallow notches enables a pawl to engage or Abe held away from a locking shoulder on the movable arm. Thus the pawl can enter the deep notches of the ratchet to engage the locking shoulder and hold the louvers open; or it can enter the shallow notches of the ratchet and be held away from the locking shoulder and permit the louvers to close. The louver-operating mechanism is so arranged that alternate downward pulls on the cord -or chain will present a deep notch and then a shallow notch to the pawl. It is therefore an object of the present invention to provide a louver-actuating mechanism with a movable arm that carries a rotatable ratchet with alternate deep and shallow notches.

The louver-operating mechanism provided by the present invention has a spring disposed above and at an angle to the l-ouvers. This spring provides an initial opening force on the louvers, but it is so set relative to the louvers that it resists movement of those louvers to fully opened position. Consequently, the one spring provides an initial opening force and an initial closing force for the louvers. Those forces are quite important ybecause they start the louvers moving toward and away from open position, and thus they assist the actuating-mechanism to effect the desired movement of the louvers. It is therefore an object of the present invention to .provide a spring that provides an initial opening and an initial closing force for louvers.

The -pawl, which is used to engage the notches in the ratchet and the locking shoulder on the movable arm, will move slightly as the ratchet and arm move relative to it. However, that ratchet will be biased to ratchet-engaging position by a spring and will normally be in ratchetengaging position, In the event of a fire in the building or structure ventilated -by the air-moving device, a second spring will come intol action and move the -pawl wholly out of engagement with the ratchet and the movable arm; thus freeing the arm for movement to louver-closing position. The second spring'is normally kept from actingby a heat-responsive link; but that link will soften and permit the second spring to move the pawl whenever a re occurs. This is very desirable because it minimizes drafts that would feed the re.

The louver-actuating mechanism of the present invention engages the switch arm of a Inercury switch and causes that arm to tilt the switch to on position. However, that switch arm is not positively .link-ed ,t-o the louver-actuating mechanism; and A*thu-.s if the'louver-'operating mechanism were to break or to shift out of engagement with the switch arm, the switch could move to on position. Such movement is assured Aby a spring which acts upon the switch arm and biases it to off position. Such ari-arrangement is very desirable because it keeps `the motor ofthe air-moving device from overheating due to operation when the louvers are closed. `1t.` is ,therefore an object of the present invention to provide va switch arm movable independently of the louveroperating mechanism and to provide a spring wh-ich acts directlyuponthat arm to bias-it to off position.

In -many lou'ver-operating mechanisms the manufacturingtolerancesfor the pivotsfor the louvers permitthe louversto `beshited by the air passing through the louvers. This shifting of thepivots causes noise, and that noise will be ampliiied'iby-and radiatedffrom the large surfaces ofthelouvers. tionable, and it is completely avoided vby the construction pro-vidediby the-present invention. That'construction includes a stiii spring which bears against la pivot on `each and every louver, and which urges thosepivots into intimate engagement `with the pivotsupports; thus minimizing-shifting oftheipivots. It is therefore an object ofthe presentinvention'to provide aV sti spring vthat biases )a pivot on\each and every louver intointimate engagement with .the pivot supports.

The stiff .anti-rattle spring provided by the present inventionis vpreferably threaded through notches yformed in Athecasing of fthe air-moving device. Those notches'willparallel a line passing through the pivots of the vvarious louvers, and they will tend to hold the spring parallel to although spaced from the line .extending through the pivots. -Consequently the spring must be :distorted vto pass `around ,the pivots, and that spring will'tend to restore'itself; and in-doing-so-itwill provide a steady and constant force on the;pivots.

Other and Afurther v objects r and advantages of thepresent invention `should become apparent from an examination of the drawing and accompanying description.

In the drawing-and accornpanyinfr description a preferred embodiment of the present invention is shown and described but it is to be understood that the drawing and accompanying description are -for the purposes of illustration only anddo not limit `the invention and that the invention will bedei'lned by the appended claims.

In the drawing,

Fig. l is a cross-sectional side View of an airmoving device that ismade in accordance with the principles and teachings ofV the present invention.

Fig. 2 'is an-enlargedrside elevationalview of the casing -for -the -louver-operating -mechanisrn provided by -the present invention,

Fig. ..3 is Va partially-broken, cross-sectional end View of .the Ycasing and .louver-operating,

Such noise'is very objecmechanism provided by the present invention,

Fig. 4 is a larger side View of a portion of the angle and spring shown in Fig. 1, and

Fig. 5 is a side elevational view of a ratchet and part of a rotatable arm used in the airmoving device shown in Figs. 1 3.

Referring to the drawing in detail, the numeral I denotes a housing for an air-moving device. That hou-sing is provided Vat its upper end with ya Venturi ring i2 which denes a IG. A number of resilient mountings I4,

are secured tothe upper surface of the housing HJ.

'These --moun-tingsare-generally annular in form and-each'ofethem'i'sidisposed adjacent a circular fopening;not'shovvn. The mountings Ui surround andfare.s ecured.to stanchions IS, and they enable those stanchions to move up and down and fromf'sirieito side relative to the housing ill. The weight of the stanchions. IB, and the apparatus supported ,:thereby,; isresisted Aby shearxandzcompressive forces Withinathe mountingsi'd.

The :stanchions t6 vcarry a .horizontally-.disposed bearing supportzlfpand'that bearingzsupport :carries .a sleeve bearing 2t adjacent the center thereof. .A vshaft 22 is disposed and-held within the bearing 2-2'0, and that -shaft :'carries a fan hub .24 vat the lower-endthereof. Four 'blades :25 are securedfto the fan hub 2li.and those blades `rotate Within .the Venturi ring i2 to move air relative to that Venturi'ring. A pulley 25 isprovidedat the upper "end of shaft 22, and that pulley receives -a belt-3 which is driven-by apulley-Si 1on-the shaft of motor Y32. The motori-.3 2 is secured to thebearing support if), and it -is disposed adjacent `one of the stanchions l. Electrical'leads ,34 extend from the motor 32; and `those leads extenddownwardly through housing l0 to the vicinity of theflouveroperating mechanism. Y

The housing M3 .1 has ,-anlangle'. disposedalong two of the oppositeI edges thereof; only oneof theanglesbeing shown inthe. drawing. The two angles .35. are drilled to receive .the-ends .of a plurality of vhorizontally spaced rodsv 138. ,The rods.38 support louvers .49; the louvers 49 being secured so tightly .to the rods 38 `that -the rodsSS and the louvers'A rotate together. Each of the louvers A0`has a projection 42 thereon, and each of theprojections V421ispivoted to an actuating rod 44. The actuating rod 44 thus holds all or" the louvers 40 for conjoint rotation about their pivotvro'ds'38; and that rod will move both vertically and'horizontally as the louvers 4D rotate to and from closed position.

An extendible spring vll6'is 'secured to the actuating rod 44 'adj'acentfone end thereof', and the other end of that spring is attached to the housing 10 at a'v point above Aand to the right of the rod 4d. 'Since ithe rod 'M5 must move upwardly in opening jthelouversli, the'securement ofthe otherend of'spring 46 tothe housing I0 at a point` above'1od`"l3"4 `enables that spring to provide an initialppening-force on louvers 4i). Since-the rod 44 4must move to the left in opening the `Vlouvers '40, mthe'securernent of vthe other end V'of lspring 46 to the housing m at a point to the-right ofrod'li-'enables that spring to provide an initial closing Aforce on the louvers 43. Thus,` spring Aiperforms .the .dual :function of l helping Vto; open andhelping .toclose .the louvers MJ. -InMmoving/.rom open vto. closed position the LlouversA-subtendan ,angler of. approximately ninety ()..d.grees, Vand :the direction of action `of'spring'i alwayswithin that ninety V(90) degree angle. Y.

' Ar plurality lof *notches* 48' are 1provided `in the angles 36 secured `toh'ousir'igjlyand springs 50, preferably ofv piano wire-fare threaded throughI those notches'.4 Thereare-preferably-two springs 50, one for each angle 88; and vthosesprings are threaded through the notches 48 in such-a way that they alternately pass through a notch'and over a pivot rod 38; The notches 48 define lines that are parallel tobut arelspaced belowthe lines defined by the ends rof Athe pivot rods 38; andy the springs 50 tend to lie in the linesdefined by notches 48. In being passed over the'rods 38 the springs 58 are distorted, and they tend to restore themselves to the lines defined'by notches 48. In doing so, the springs 50l hold thelpivot rodsy 38 tightly against the angles 36; thus taking up'allslack due to manufacturing tolerances. As a result, the springs minimize all tendencies of the louvers 40 to rattle 4'and make noise.

A casing 52 is providedadjacent one Vwall oi the housing I0, and that casing supports and largely encloses the louver-actuating mechanism provided by the present invention. The casing 52 has two

arcuate slots

54 and 56 therein; and slot 56 is dimensioned to receive a pin 58. This pin has a connecting rod 60 secured to the front thereof, and that connecting rod is pivotally secured to the actuating-rod 44 by'a pin 62. A dog 64 is secured to the rear of pin 58, and that dog rotates relative to the pin. Dog 64 is biased for rotation in a counter-clockwise direction about pin 58 by the spring 66. One end of the spring 66 bears against a notch in the end of the dog 64, and the other end of the spring 66 is held in the slotted rear end of the pin 58. f

The pin 58, dog 64, and spring 66 are mounted on a rotatable arm 68 which is secured to the casing 52 by a pivot 10. This pivot permits the arm 68 to be rotated relative the casing 52, and the' arm 88 is dimensioned so the pin 58 will move in the slot 56. A pivot 12 is secured tothe free end of rotatable arm 68; that pivot being disposed in register with the arcuate slot 54, and extending through thatslot. The rear endl ofthe pivot 12 rotatably supports aratchet 14 which is providedwith alternate deep and shallow notches. The notches of ratchet 14 are so directed that they can be engaged and 'held by the free end of do'g'64; the' spring 66 biasing that dog into engagement with vthe notches jof ratchet 14'.

` A chain 11 is providedto apply opening forces to the vlouver-operating inechanism, and that chain is connected to pivot 12 by means of extensiblespring 16. In the event the pull on chain i1 is unusually strong or is continued unduly, no

above slot 54, and that pivot rotatably supports a pawl 88. The free endpof'the` pawl 80 is Vlocated adjacent the ratchet 14, and it can engage the alternate shallow and deep notches of that ratchet. Whenever the free end of pawl 80y is in engagement Ywith one hof. the deep notches of ratchet 14, it will'be in engagement 4with .the locking shoulder 69 on'therotatablegarm 68 c. IIow.v ever, whenever, Vthe freependfopawl .80.is `in. en.

.enligneA 6 gagement with one of the shallow notches of ratchet 14, it will be held above and out of engagement with that locking shoulder. The locking shoulder 69 is disposed to the right of. a gently rounded projection on the free end of arm 68. A spring 88 has one end thereof secured to a stud 84 on pawl 80 and has the other end thereof secured to stud 86 on casing 52, and that spring biases pawl 'into engagement with the notches of ratchet 14.

An opening 82 is provided in the casing 52 adjacent the upper end of pawl 80, and that opening receives the stud 84 on pawl 80. The 'diameter of stud 84 is smaller than the diameter of opening 82; consequently stud 84 can move freely in opening 82 as the pawl 80 moves relative to the ratchet '14;H Spring 88 normally holds stud 84 adjacent the'left hand side of opening 82, but that stud will move toward the other side of opening 82 when the armi 68 moves the ratchet 14 to the left past the vfree end of p'awl 80. Thatstud will also be moved to the right side of opening 82 if a fire occursH adjacent the air-moving device; heat-responsive link 92 softening and permitting Yspringv 96 to tighten cable 8| and pull studr84 to the rightof opening 82. Ordinarily, the heat-responsive link 82 will be intact and will resist the forces in spring 96; that spring being extended between theY right hand end of link 82 and the stud 94 which is secured to casing At such times, the left handnen'dl of link 92 will be` held by stud 88 on casing 52, and the cable 9| will be free of tension.r However, when the link 82 softens, the righthand end thereof will be freed from the left hand Vend thereof and will move under thevaction of spring 9,6. In doing so it will tighten cable 9| and `will pull stud 84 to the right side of opening 82. This rotates pawl 86 completely out of contact with ratchet 14, thus freeing arm 68 for movement to louver-closing position. Y

A portion of thetop of casing 52 is bent out-L wardly to provide asetion 88 of increased depth to receive mercury switch I |0 and the upper end of switch arm |02. That arm rotates about a pivot |86 secure'd to the rear of the casing 52; and it is biasedfor'rotation in a counter-clockwise direction by spring |06 which is held by stud |64. .Stud |04r receives one end of spring |06; that spring passing around pivot |00 and then being slipped behind switch arm |02. Spring |06 normally holds switch arm |02 in the off position; but switch arm |02 is so dimensioned and disposed relative topin `58 that the pin 58 will strike the lower end of arm |02 and move the switch H0 to ,on position. Spring |86 is strong enough to hold the switch arm |02 in the orf position when thepin 58 does not engage arm |02, but itwillyield and permit pin 58 to move arm |02 to the .on..position. The switch |||l is held by a yoke |88 secured .to the upper end of the arm |02, andl theleads 34 from the motor extend to the switch I l0 .and to an electrical out let, not shown.

YWhen the louvers 40 are in closed position, the entire and combinedweight of louvers 40, actuating rod 44, connecting rod 60, movable arm 68, and ratchet 14'wil1rtend to respond to gravitational pull and hold the louvers closed. While spring 46 provides aforce biasing the louvers out of closed position, it cannot alone cause opening of thoselouvers. While the louvers y4|) are in open v position, as, shoWnin-jFig. ,1-`, the centers of mass 0f each of: Athe-louvers Anpaotuatingrod ,44, conf nectingrod (i0, movable. arm..68 and.ratchet .1.4 will beQdisplaced above their closedpositions; and all that isneeded .toy closethe louvers-.4"0.isl.to.in cline them to .theright .of `the vertical. The spring li will provide that inclination.

When thev louvers 4.0.are in close'd position, the movable arm '6.8 will" be adjacentthe right. hand en'ds of the arcuate slots'54 an'd'56. When the louvers '4U are to be opened, a .downward pull will be applied to the chaini'l; and that .pull will be transmitted around `pulley 'I5 and'. through spring '16 to the pin12. nThatI pull will causethe arm 68 to rotate in a counter-clockwise direction about pivot', and such rotation .will move the actuating rod 44 upwardly and to theleft; spring 46 assisting such movement. .The movement of rod 44 will cause `each'of the louvers 40 vto open. As the arm 68 continues'to rotate in a counterclockwise direction the. gently rounded. projection on the endof arm 68will engage and pass under the free end ofthe pawli; that projection acting as an inclined plane'toraise the `free end of pawl 80. That freeY end 'of pawl B'will drop into a shallownotch of ratchetj'li, will ride'along the next inclined face 'of Yratchet T4, A"and will nally drop into a deep-notchofratchet T4. vThefrictional engagement'between-"pawl i'andf the inclined faces of ratchet '14vvill `notrotate'that ratchet in a clockwise direction, because'dog B4 prevents any and all "such rotation. Further counter-clockwise movementofarm 68 will be resisted by engagement-,of pin *58"withth'e left hand-end of slot-56; theupawl Y8l) being'purposely set adjacent the -ends of slcts54and `56 so only two notches pass under pawl' when arm 68' is movedto' thelefthand endsofslots 54 and 56.

The pullfon the-chain 'H `can then bel-released, and the-spring' 46S-will then `act throughactuating rod 44 and-'connecting'rodv'to'pull arm 68 ina clockwise direction'l untill the pawl 8 0 engages and holdsthe2 locking'sholder 69A on arm B8. Thereafter, until another downward pull is applied to chain `TI, or untilaf'llre occurs, the-pawl 8D .will hold-arm l'8against louver-closing movement. As `the arm 68 movedy in the counter-clockwise direction, thepin 58ithereon engaged switch arm |02 and moved the switch v'I Il] to on" position. The louvers.!!- willthus bellieldiopenv and the air-moving device Vwill :be energized,

Inthe. event. of1.a re in lthe vicinity of the airmoving device, therheatiffrom there will soften heat-responsive' link .92. Thereupon, the-spring S5 will pull :the-right .hand `.portion of Alink C92 and the cable:9.l...to1the. right, .thus rotatingpawl Bout of contact with the ratchetf'li4. andV the'arm 5B. This vwillpermit spring i4ito. startLthe. louvers 49 toward closedposition, andathe weightofthe louvers 49actuatinggrod 44, connectingrod, and arm Will;quickly .close'the louvers 40, .In closedl position, rtheifreeends of louvers 4U will overlie the pivotrodslof the. adjacent louvers1 thus obstructing free Aiiow .of air.

When the louvers 41have1been. inopen. position, and itis .desiredto lclose thoselcuvers, .it is only necessary to exert a downward.pull;on;chain 1?. That pull willmovefthearmilin -azcounterclockwise direction; movingY .the :next .shallow notch. of ratchetil under theffreeI end of pawl 80. Release of thatj pull Awill enable spring 46 to :start the arm 58m. a clockwise direction; andfbecause that shallow .notchwwill hold the .end .ofithe Ipawl above theslockinggsshoulder 69 kof..arm .'68, the arm 68 .willnotzbeheldiby pawl8ll` and-will move to louver-closing position. Asl the armi B8 vmoves in aclockwisedirection, it willfreeithe switch arm |02 .for rotation to offpostion, thus .deenergizing motor'32.

The .deep `andshallow notchesin ratchet. are circumferentially -spaced .apart distances which coact with the positioning-.of .pawlla relativelto slots 54 .and -56 vto assure the passage ..0 two notchespastpawl when arm 68 is moved from closedlto-.open position. and to .assure the passage of..one notch pastpawl when Varrnl is moved from open positionto .theleft-hand end .of slot 56. Suche. construction minimizes-theskill required of the operator, vand it .avoids accidentalv closing of the louvers.

Whereas a preferred embodiment of thepresent inventionhas beenshown and described in the drawing and accompanying description, it shouldbe obvious to thoseskilled inthe art'that various changes maybe madein the :form of the invention Without .affecting the scope .thereof.

-WhatfI claimis:

l. A louver-operating mechanism that comprises an actuating arm, a linkage which is secured to said armI and to'louvers and is-movable by saidfarm tofmovesaid. louvers, a ratchet carried by. saidactuating arm,y a .pivot that rotatably securessaid-ratchetto said-:actuating arm, said ratchet yhaving alternate deep .and .shallow notches, a locking surface on. saidfactuating arm adjacent .said ratchet.. a; pawl` disposed: intermediaterthe ends ofthe path of travelofnsaidactuating arm and disposed to-engage said-ratchet and said locking surface, said shallow `*notches .being disposable above` said locking surfaceon saidactuating. armI to` hcld.saidpawl-above. andy outof engagement -with saidfllocking surface, said .deep notches.beingdisposable below saidlocking surface on said actuating arm to .permitsaid pawl to .engage said locking surface, said pawl being adapted tolodgein a deepnotch of .said ratchet and engagesaidflocking surface vofsaidarm or to lodge'in-a .shallow notchtof said ratchet and beheld out of engagement withsaidlocking surface onsaidarm, .saidshallow and deep-notches being .alternatedaround lthe .periphery ofv .said ratchet.

2.1.A'1ouver-operating mechanism that comprises .an actuating arm,y a linkage which is secured tosaid. arm and tolouvers and is movableby said arm to move Vsaidlouvers, a ratchet carriedby sai'dactuating arm, a pivot'that rotatably secures said'ratchet to said actuating arm, sai'dratchet'havingalternate deep and shallow notches, a'locking surface on saidactuating arm adjacent said ratchet, al pawlA disposed intermediate'the ends of 'thepath of travel of saidv actuating arm vand disposed to engage said ratchet and said .locking surface, said shallow notches being disposableabove said locking sur- .face on saidactuating arm to hold said pawl above and out ofengagement with said locking surface, said deep notches being disposable below said locking surface* 'on said actuating arm to permit saidpawlito engage'said lockingv surface, said pawlbeingadapted to lo'dgein a deep notch of 'said ratcheti'and'engage said locking surface of `saidarm-ortolodge ina shallow notch of said ratchet and-beheld out of engagement with said lockingsurface ofsaidrarm,'-saidarm being movable past-said pawl and-then' backV` towardsaidv pawl tofenable `said pawl-'tof'engage alternate notches in said ratchet, A\said.ratchetibeing .rotatable by said:pawlzand.alternatelycarrying said pawl into engagement with; .orfcarrying :said pawl above andwout of .engagementfwitn .said :locking 'suri'ace on said arm, said shallow and deep notches being alternated aroundv the periphery of said ratchet. l

3. A louver-onerating mechanism that comprises a plurality of pivots, a plurality of louvers that snbtend a predeterminedangle in moving from closed to open position, a horizontal frame for supporting said louvers, a-rod connecting said louvers for conioint movement. a spring, and an anchor for said spring, said anchor being above and to one side of the pivot for lone of said louvers, said anchor and said pivot defining a line that is approximately midway between the open vand closed positions of said one-louver, onev end of said spring being stationary as by being secured to said anchor, the other end of said spring being selectively movable with said one louver to one or the other sides of said line, said spring being distorted when said other' end thereof is onl said one side of said line, being relaxed when said other end thereof passes through said line, and being again distorted when said other endthereof is on said other side of said line, said other end of said spring being on said one side of said line whenever said louvers are in closed position, being on said line whenever saidone louver is approximately midway between closed and open position, and being on saidother side ofr said line whenever said louversY are in open position, whereby said spring applies'an initial opening force to said louvers whenever said louvers are in closed position and applies an initial closing force to said louvers whenever said louvers are in open position. Y

4. A louver-operating mechanism as claimed in claim 3 in which said spring is an elongated helical extension spring, in which-said line is spaced from the closed position of Asaid louvers by approximately forty-five degrees, and in which said other end of said spring is secured to said rod adjacent said one louver. ,l

5. In a louver-a-ctuatingmechanism` the improvement thatcomprises a movable armgga linkage that is secured to saidrnovable arm and to louvers, said linkage being movable by said movable arm to move said louversito open and closed position, a pawlthat releasably holds. 'saidxarm in louver-opening position, said arm being movable from louver-closing position to and past said louver-opening position, a chain, and a spring disposed between said chain and said movable arm, said chain acting through said spring to apply forces to said arm to cause said arm to move from louver-closng to and past louveropening position, said spring being yieldable te prevent application of undue forces to said movable arm during such movement of said arm.

6. A louver-operating mechanism that comprises an actuating arm, a linkage which is secured to said arm and to louvers and is movable by said arm to move said louvers, a ratchet carried by said actuating arm, a pivot that rotatably secures said ratchet to said actuating arm, said ratchet having alternate deep and shallow notches, a locking surface on said actuating arm adjacent said ratchet, a pawl disposed intermediate the ends of the path of travel of said actuating arm and disposed to engage said ratchet and said locking surface, said shallow notches being disposable above said locking surface on said actuating arm to hold said pawl above and out of engagement with said locking surface, said deep notches being disposable below said locking surface on said actuating arm to permit said pawl to engage said locking surface, said pawl being radapted to lodge in a deep notch of said ratchet and engage said locking surface of said arm to lodge'in a shallow notch of said ratchet and be held out of engagement with said locking surface onsaid arm, said pawl being so dimensioned and being so disposed adjacent one end of the path of travel of said arm that movement of said arm from closed position to said end of the path of travel will carry two of said notches past said pawl.

7. A louver-operating mechanism that comprises an actuating arm, a linkage which is secured to said arm and to louvers and is movable by said arm to move said louvers, a ratchet carried by said actuating arm, a pivot that rotatably secures said ratchet to said actuating arm, said ratchet having alternate deep and shallow notches, a locking surface on said actuating arm adjacent said ratchet, a pawl disposed intermediate the ends of the path of travel of said actuating arm and disposed to engage said ratchet and said locking surface, said shallow notches being disposable above said locking surface on said actuating arm to hold said pawl above and out of engagement with said locking surface, said deep notches being disposable below said locking surface on said actuating arm to permit said pawl to engage said locking surface, said pawl being adapted to lodge in a deep notch of said ratchet and engage said locking surface of said arm or to lodge in a shallow notch of said ratchet and be held out of engagement with said locking surface on said arm, said pawl being so dimensioned and being so disposed adjacent one end of the path of travel of said arm that movement Vof said arm from open position to said end of the path of travel will carry one of said notches past said pawl.

8. A louver-operating mechanism that oomprises an actuating arm which is movable to move louvers, a ratchet carried by said actuating arm, a pivot that rotatably secures said ratchet to said actuating arm, said ratchet having alternate deep nd shllow notches, a locking surface on said actuating arm adjacent said ratchet, a pawl disposed intermediate the ends of the path of travel of said actuating arm and disposed to engage said ratchet and said locking surface, said -shallow notches being disposable above said locking surface on said actuating arm to hold said pawl above and out of engagement with said locking surface, said deep notches being disp-osable below said locking surface on said actuating arm to permit said pawl to engage said locking surface, said pawl being adapted to lodge in a deep notch of said ratchet and engage said locking surface of said arm or to lodge in a shallow notch of said ratchet and be held out of engagement with said locking surface on said arm, a spring adapted to move said pawl out of engagement with said ratchet and said arm, and a heat-responsive element that normally keeps said spring from acting upon said pawl.

9. A louver-operating mechanism that comprises an actuating arm, louvers that open and close in response to movement of said actuating arm, a linkage that is secured tosaid actuating arm and to said louvers, a locking surface on said arm, a pawl that can selectively engage said locking surface on said arm to hold said arm, and a rotatable ratchet carried by said arm that has deep and shallow notches therein, a pivot that rotatably secures said ratchet to said actuating arm, the deep notches of said ratchet being adapted to permit said pawl to move below the level-of` and into the path of said'ilock'ing surface on said -arm and therebyrpreven'tmovement of said actuating arm While the shallow'notches of said ratchet are adapted to hold'said pavvl aboveand out ofthe path of said locking'surface on said arm and thereby permit movement of'said actuating arm; alternate pulls on saidarm moving alternate notchesof said ratchet-against said pavvl, thereby causing rotation 'of said ratchet for alternate presentation of said deep and shal- W notchesi 10. A louver-'operating mechanismthat`r comprises an actuating' arm, louvers thatopen and close `in response to movement of saldi actuating arm, a linkagefthat "is'secured to said actuating arm and to said louvers,` said linkagebeing movable by said actuating arm to move said' louvers, a' locking surface onfsaid arm, a` .pawl that' can selectively engageV said locking'surface on said arm to hold said arm, and a rotatable ratchet carriedby said arm that has deep' and'sha'llow notches therein, the 'rdeep' notches of fsaid/ ratchet facilitating prevention of 'movementi of 'i said actuating arm" by permitting saidY paWl 'to`pass' below the level of'and'engage saidllockingsurface on said'arm; While the shallow notches`^ of said ratchet facilitate movement vof said'actuatinfg arm by holding said'pawlabove andoutof engagement f with said locking surface on saidarm; alternate pulls on saidarm causing rotation of said ratchet' for alternate presentation of said deep and shallow notches, said shallow and deep notches beingalternated on the circumference of said ratchet;

11. In a louver-operating mechanismI which has aratchetL a pivotfor said Aratchet .that permits rotation of said ratchet, a' pawlengageable with said ratchet, an actuating arm that-has a locking'surface'thereon and that'is movable relative to said pavvl,l anda spring'secured tosaid actuating arm that biases said actuating arm for movement, said actuating arm carrying said pivot for said ratchet and selectivelymoving said ratchet'into' engagementwith said pawl; said pawl'being movable to arm-lockingor arm-freeing' position With said 'locking surface, said ratchet havingnotches of alternate depths to selectively hold said pawl in arm-freeing or arm-locking position, said actuating arm being movable againstrthe biasinggforce :ofxsaid :spring to cause relativeemovementl*between at? least one of YVthe notches of said ratchet and said pawl, said actuating arm 'beingv returnable by said spring to cause` engagement of -said notch` and said pawl.

12.v A lower-operating` mechanism that comprises an actuating a-rm'vvhic-hV is movable to move louvers,` a-.pawl that ,isypivrzitally mounted von a stationary part of said louver-operating mechanism `and that` is .adjacent the path 4of travel of said arm and .that Vis disposedi intermediate the ends ofwsaid path of travel =of said arm, said pawl being engageablewith. said; arm to hold said louvers again-st: movement, a normally distorted spring secured,Whollyfawayffrom-said pawl but being inactivelyY attached to said pavvl, a normally inactive actuator which can respond to movement of said spring to mofvesaidppawl out of engagement with saidractuatingvlarm-and thereby permit saidarm -to move,- and ,aheat-responsive link that .normal-ly keeps said spring from causing said actuator-to move-said lpavvl.

CARL M. BUTTNER.

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