US2316235A - Automatic flap control for airplanes - Google Patents

Description

April 13, 1943. GAST 2,316,235

AUTOMATIC FLAP CONTROLS FORAIRPLANES' Filed Oct. 23. 1940 Inventor:

Patented Apr. 13, 1943 UNI STATE aurorm'rlcrmr coN'rRon Fon a 7 AIRPLANES n.

I l'slrlch Gastybessamvestedi'n the-Alien 1 1 l ropertycustodian v Y hpplicationoctober 22, 1940;, Serial No.. 1ss2,425 r i v InGermanyJuly 10,1939, (Cl. 244-78)"- v v II CIaim s. This inventionrelates to automatic flap controls for airplanes. The use of flaps and the likefii'orjincreasing the lifting power of airplanes is constantly@increasing, and experience has i shown the need of means for, automatically returning these flaps to or towardstheir inoperative positions when the-air pressure; exerted the "flap; and to inount the cylinder for'm'ovement so" that through this movement the ilap;

inclination may bevarled I v t g A further object, of the invention is to provide such'amautomatic flap control whereinjthe' cylinder is supported by a lever one extremity of "against them exceedsa predeterminedmaximum and threatens to become dangerous. Y QITo' this end arrangements have which have not proved entirely satisfactory; For instance hydraulic means have been employed to their inoperative positions when the air: presbe'endevised having relief valves set to open at certain pres:

1 sures and therebypermit the retumof the flaps w sure acting against them becomes excessive. Due, however, bothfto' the friction to be overcome in the mechanism itself and the wind resistarice against which the flaps have to be moved to theiroperativepositions it is oftenfound-impossible to use such an arrangement because the "pressure required to overcome both the friction and the air resistance to move the fiapsoutwardlyn V {is greater than thatrequiredmerely toretain {the flaps in operative position even when they are subjected to such excessive air pressure'as to threaten their destruction. The next step then thevalve setting was a tedious lob involving a number of. test flights, and often then only rtesulted in a more or less approximately-correct setting. 11 v 1 It isan object of this invention to provide an; i V automatic flap control by which the above named drawbacks are overcome and wherein more sen-e fsitiver'neans are provided for moving the flapto L fits operative position and retaining it in that r position unless and untilthe air pressure actin f against it exceeds a predetermined: limit, and t when that limit isexceeded movingthe flap to or towards its inoperative position until therair load acting againstit dropsbelow the aforesaid fl jlimitmhereupon the flap is again moved to its operative position. I ":Another object of the invention is to provide an automatic nap control including auhydraulic cylinder having a piston therein adaptedtomove which moves between stopsagainst one of which the lever is normally held: and wherein a mechg afnism operated by movementof the lever releases thepressure-inthe hydraulic-feed line to the cylinder. n' Q Yeta'nother object of the invention is to pro'- vide such an automatic flap control wherein means areprov'ided for preventing fluttering of the ,flap during cylinder;

movement of the lever and Another objectof the invention'isto provide such an 'automatic flap control wherein the hymechanically or i draulic circuit may be either electrically controlled. V n

Still another object ofthe invention is to providean automatic flap control in one embodi- V ment of which movement of theleve'r from its normalposltion breaksan electric circuit and cuts oif the hydraulic now to the 'cylinder'where v by thelflap-ismoved to and retained inits operative position, and wherein upon completion of the pivotalmovement of the lever a second electric circuit is closed whereby the hydraulic system is set to permit movement of the pistonvin the cylinder by which the flap is returned to its inoperative position. Y

Having thus briefly of the objects and advantages of. the invention ing, in which: n Figure 1 illustrates a diagrammatic view of the I will-now describe ,two preferred embodiments thereof with the-aidof the accompanying drawinvention wherein'the hydraulic now is mechanically controlled, and

Figure 2 showsia modification thereof wherein the hydraulic mechanism" is -electrically con "trolledn. r n W x a n r Referring to Figure 1, 1 denotesatank con nected by a suction pipe 2 to a pump 3 from which liquid under pressure is delivered to a rotary valve 5 through a discharge pipelfrom which a return line ill having a relief valve 9 therein, extends back tothe tanki toelimit the pressure of the liquid discharged thelp urnp.

The rotary valve I has fourconnection's; one

connected to the discharge pipe 4, one to 'a return connection I I extending back to the tank I,

- one to a flap operatingline l2, and onev'to'a flap return line It; provided in this valve is a rotary and Y broadly statedsome t plug a having three separate passages 6, I and than the valve 32.

8 formed therethrough.- By the passage 6 the discharge pipe 4 is shown connected to the retum connection II, and the passages I and 8 are then inoperative. However by turning the plug 5a, the discharge pipe 4 may 'be connected through the passage 8 to the flap operating line I2 at which .time theflap return line I6 is connectedby the passage. 1 to the return connection I I, orthe discharge pipe 4 may be connected to the fiap return line I6 through the passage I at which time the flap operating line I2 is connected through the passage 8 with the return connection II. When the rotary plug 5a is in either of these latter positions the passage 6 is inoperative,

end I3 of the cylinder ing movement of the lever 22 towards the stopv Pivoted on a pin 2 I, supported from a fixed portion of an airplane, is a lever 22 mounted for movement on one extremity of which is a cylinder I I 4 having a piston I'I therein from which a rod I8 extends. Pivoted on a pin I9 supported by another fixed portion of theairplane is a flap 20.

to which the outer extremity of the rod I8 is soconnected that movement of the piston IT, or of the cylinder I4 when the piston remains sta tionary therein,.causes movement of the flap 20 about the pin I9. The flap operating line I2 and the flapreturn line I6 are connected to opposlte'ends I3 and I5'of th said cylinder respectively, and, since the cylinder is intended to ,move somewhat when the lever 22 swings about its axis, the lines I2 and I6 are'made sufficiently flexible to permit such movement.

q The extremity of the lever 22 remotefrorn the cylinder I4 extends between two stops 24 and 25 mounted on fixed portions of the airplane, and

. which limit the swinging of the lever 22 in both directions. 'Mounted also one fixed portion of the plane and in threaded engagement therewith is an adjusting screw 23' having one extremity of a coil spring 23seeured thereto and its oppositeextremity secured to the free end of the lever 22. This spring tends to retain th lever 22 against ,thestop 24 and the cylinder I4 in itspositionshown; by adjusting the screw 23' the ten- "sion of the spring. may be varied. Thus maximum air pressure to be'withstood by the flap 20 when turned to its operative position, before movement of the lever 22 about the pivot pin 2I and therefore movement of the cylinder I4 occurs,

maybe varied. Extending from the flap operating line I2 is a branch I2a terminating in a valve chamber 28 having a piston valve 2I.therein. .Arod 26 extends between and is connected at opposite 'ex tremities to the lever 22 and to the valve 21. Ex

tending also from the valve chamber 28 is a relief line I la from which a circulating pipe 33extends having a relief valve 32 therein and connected at its opposite extremity. to the flap return line I6; the relief line lId is also preferably connected to the return connection II through a pressure retaining valve 3I set to open at a higher pressure The opDOsite ends of the valve chamber 28 are connected by a by-pass pipe 29 having a suitable valve 30 therein to retard the flow of liquid in either direction through the said pipe and prevent rapid reciprocation of'the piston valve 2I1and consequent fluttering of the flap 20 sure exerted against theflap 20.

- connection I I.

stop '24, and if during this movement excessive.

air pressure continues to be exerted against the flap the lever continues to swing until it strikes the stop 25. During the first part of the swing- 25 the piston I1 is held stationary in the cylinder I4 by hydraulic pressure from the flap operating line I2, but when the lever has moved suiiiciently to cause such movement of the piston valve 21 that the branch I2a is connected with the relief line I Ia through the valve chamber 28 then liquid under pressure flows from the flap operating line I2 through the circulating pipe 33 and the relief valve 32 to the .flap return line I6 and thus to thecylinder end I5. Then the flap 20 is swung back'towards its inoperative position by movement of the piston I! pushed inward by air pres- However as soon as the air pressure acting against the flap drops below that for which the spring 23 isset, that spring moves the lever 22 back towards the stop 24 thereby moving the piston valve 21 to sever the connection between upon pressure is again built up in the cylinder end I3 and at the same time the cylinder I4 is moved forward towards its normal position.

If it is desired to render the flap 2!] inoperative for normal flight the valve 5 is so set that the discharge pipe 4 isconnec ted to the flap return line 7 I6, and the flap operatin line I2 to the return cylinder end I5 which retains the piston I'I atiits rear position in the cylinder I4. a

In the modification shown in Figure 2 the same ,mechanism is electrically instead of mechanically v operated. The tank I, suction pipe 2, pum 3,1

discharge pipe 4, and return line III with its relief valve 9 are again employed. The discharge pipe 4 is connected to a ,valve 34 to which a return connection II and an actuating pipe 46 are also connected.- In the valve 34 is a plunger 31 which is normally retained in its position shown by a spring 40 so that the discharge pipe 4 is connected totheretllrn connection II; Howeveriby energizing the solenoid 43 through an electric circuit hereinafter described the plunger 31 is moved to close the return connection 'II and affordrcommunication between the discharge pipe 4 and the actuating pipe 46.. The latterterminates in a valve 35 having a plunger 38 therein .,-nonnal1y retained in its position shown by a spring 4I so that the actuating pipe 46 is normally connected to a flap operating line I2b which terminates in the end I3 of the cylinder I4. Ex-

ating line 45 upon movement of the plunger 33 tending from-the valve 35 is alsoa flap return line Ifib which terminates in the end I5 of the said-cylinder and which is connected to the actu by the solenoid 44, whereupon connection between the actuating pipe 46 and the flap'operating line I2b is interrupted. 7

Extending from the returnconnection II is a relief line IIb having apressure retaining valve 3Ia therein and terminating at its opposite extremity in a valve 36, between which and the said' valve 3 la a circulating pipe 33a is provided which connects the relief line I Ib with the actuating I4 and the flap 2D is turned The pressure is exerted in the pipe .46 and has a relief valve 32a therein. A

. plunger 39 in the valve 38 is normally soheld by a spring 42 that the relief line i lb is' connected tofabranch l6, of theiiap return line lib, but

, when the plunger- 39 is moved by a solenoid'45 it connects the relief, line ljlb with a branch l2 of the flap operating line l 2b.

The arrangement r the cylinder 14 with its piston l1 and rod l8 connected to the fiap2ll pivoted on a pinl 9 is the same as before, andthecylswitch is closed, are connected to a lead 64. Ob-

inder is again secured to the pivoted lever 22 the I free extremity of .whichlswings between the two stops 24 and and is normally retained against of the lever 22 in contact with the latter adjacent its free extremity, and the lever is so constructed as to constitute insulation between the contacts 41 and 48. When the lever is in the position shown the contact 41 is in electrical engagement the stop 24 by a spring 23 the tension of which is i adjustable through the adjusting screw 23". Spring contacts 41 and 48 remain at all positions with the stop 24 which also functions as an elec- .trical terminal, and then the contact 48 isdisengaged from the stop125 which functions, also as ,a terminal.

, From a source of power 60 a lead 6| extends to the solenoid I43, and fromthe latter another wire 62 runs which is connected to the spring contact 41; ,When theflever 22 is in the position shown thiscontact 41 is. inelectrical engagement with the stop 24 from whicha wire 63 extends to one side of a switch 49, theopposlte side of which is [connected through a lead 64 to the source of power 60. 'Ihus when the switch 49 is closed the solenoid, 43, is operativewhenever the lever 22 is in its position shown. At that time a hydraulic flow occurs from the discharge pipe 4 through i the actuating pipe 45, valve and flap operating =line;l 2b to the cylinder 'end ,l3, thereby moving thepiston l1 and rod l8 forward and turning the i flap 20 to its operative position. Then liquid displaced from thecylinder end If; flows through the flap return line lBb and branch l6 through the valve 36, the relief line llb, valve 3la and returnline ll back to the tank I.

When the lever 22 swings away from the stop 24' the circuit through the spring contact 41 and solenoid 43 is broken, and the spring returns the plunger 31 inthe valve 34 to its position shownand closes the connection between the viously when the switch is closed'all three solenoids areienergized Then a hydraulic flow oc curs from the discharge pipe 4, through the valve 34, actuating pipe 45, valve 35 and flap return line lib, at which time the flap operatingline the said alterations and modifications fall within the scope of the appendedclaims.

What I- claim is:

comprising a pivoted lever, a cylinder mounted for substantially axial movement on one extremity of the lever, means tending to retain the lever at one end of its travel. and the .cylinderin its normal position, a piston in the cylinder, means for introducing a pressure medium'into the cylinder for moving the piston, a movable flap adapted to be moved from an inoperativeto an operative position to afford resistance to an air stream, a rod connected to the, piston and to the flap for moving the latter, and, said. flap being adapted to be moved fromitsioperative towards its inoperative position by excessive air pressure thereby moving the cylinder andlever while the piston is held stationary in the cylinder ,by the pressure medium.

'2. An arrangement comprising the combination set forth in claim 1, wherein the means tendingto hold the cylinder at one limit of its travel consists of a spring which returns the cylinder to its normal position and thereby returns the hen to its operative position when the air pressure acting against the latter drops below a predetermined amount.

discharge pipe 4 and the actuating pipe 46, and

opens the former to the return connection ll.

Due to the provision of the relief valve 3la in the relief line llb all the liquid then flows back to the tank I. When the lever 22 moves the spring contact 48 into electrical engagement with the stop 25 a circuit is closed through a wire 6| extending from the lead 8| to the solenoids 44 and 45, from the latter through a wire connected. to the stop 25 and from the contact 48 through a wire 64' connected to the wire 64.- Then the plungers 38 and 39 are so moved that the following: flow results as the piston I1 is moved to the left (Figure 2) by air pressure acting againstthe flap 20: From the cylinder end ill to the end l5 through the flap operating line l2b and branch l2, valve 36, relief line lib, circulating pipe 33a and valve 32a, actuating line 48, valve 35 and flap return line lBb.

i A third electric circuit is provided for directing the hydraulic flow so that the flap 20 is positively maintained in its inoperative position shown.

- This consists of a double switch 50 having connections 65' and 82' connected to the wires 65 l and 52 respectively, both of which, when the 3. An arrangement comprising the combination set forth in claim 1, wherein the means tending to'hold the cylinder atone limit of its travel consists of a spring, and means for adjusting the tension of the latter whereby the air pressure required to move the flap towards its inoperative position and the cylinder substantially axially may be varied.

4. An arrangement of the character described comprising a pivoted flap adapted to be moved from an inoperative to an operative position to offer resistance to an air stream, a cylinder mounted for limited movement substantially in the cylinder, a rod extending from the piston and 1. An arrangement of the character described connected to the flap to impart pivotal movement adapted to be moved from an inoperative to an operative position to offer resistance to an air stream, a cylinder mounted on the airplane for movement substantially in alignment with its axis, stops limiting the cylinder movement, a

means tending to retain the cylinder at one limit of its travel, a'piston in the cylinder having a rod extending therefrom connected to the flap position, said flap'being adapted to be moved to-v wards its inoperative position byjexcessive air pressure exerted against it and thereby move the.

cylinder towards its outer limit of travel while the piston is held immovable in said cylinder by hydraulic pressure, and valve means operated by movement of 'thecylinder for permitting equalization of the'hydraulic flow from one end of the cylinder to the other when said cylinder has been moved adjacent its other limit of travel.

6. An arrangement of the character described comprising a pivoted lever, a spring tending to retain itinnormal position, a cylinder connected to the lever for'movement therewith, a piston in the cylinder, a pivoted flap, a rod extending from the piston and connected to the flap to-move the latter, jmeans for admitting hydraulic pressure into one end 1 of the cylinder, said flap being adapted to be turned to its operative position by the pistonand towards its inoperative position by excessive air pressure acting against it thereby 'moving the cylinder and lever, valvemeans operated by movement of the lever, piping connected to the valve means and cylinder through which a hydraulic'flow'occurs from one end of the cylinder to the-other when said valve means is opened to permit movement of the piston in the cylinder,

cylinder to their normal positions when the air pressure acting upon the flap drops below a predetermined pressure and means permitting the escape of hydraulic pressure from the other end operated valve means whereby hydraulic pressure -30 said spring being adapted .to return the lever and I,

may also be exerted in the other end of the cylinder to positively retain the flap in its inoperative position. 7

9. Anarrangementof the: character described comprising a cylinder mounted for substantially axial movement, a piston therein, means including valves for admitting a pressure medium into either end of the cylinder, mechanical means for selectively operating the valves, a pivoted flap adapted to be moved either position or to an operative position to ofier resistancetoan air stream, a rod connected to the piston and to the flap to move the'latter, said flap being'adapted to be moved from its operative towards its inoperative position by excessive air pressure acting thereagainst thereby moving the cylinder when the piston therein is held immovable in said cylinder by the pressure medium, and means tending to return the cylinder to its initial position.

'10. An arrangement of the character described comprising axial movement, a piston therein, means including valves for admitting a pressure mediuminto either end of the cylinder, electrically operated means for selectively operating the valves, a pivoted flap adapted to be moved either to an inoperative position or to an operative position to offer resistance to an air stream, a rod connected to the piston and to the flap to move the latter, said flap being adapted to be moved from its operative towards its inoperative position by excessive air pressure acting thereagainst thereby moving the cylinder when the piston therein is held immovable in said cylinder by the pressure medium, and means tending to return the cylinder to its initial position.

11. An arrangement of the character described comprising the combination set forth in claim 10, including a lever on which said cylinder is mounted, and the electrically operated means being operated through movement of said lever.

ERICH GAST.

to an inoperative 9, cylinder mounted for substantially

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