May 3, 1949. W. P. LEAR 2,469,269 UNITARY MECHANICAL ACTUATOR DEVICE Filed April 17, 1943 3. Sheets-Sheet l

INVENTOR. w Ala AT TORNEY May 3, 1949. w W. P. LEAR 2,469,269 UNITARY MECHANICAL ACTUATOR DEVICE Filed April 17, 1943 3. Sheets-Sheet 2

INVENTOR,

4. 14- ArrorNEY May 3, 1949. W. P. LEAR 2,469,269 UNITARY MECHANICAL ACTUATOR DEVICE Filed April 17, 1943 3. Sheets-Sheet 3

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tos 20 30 40 so cozo 17/17. A 614 - M20/MM4s INVENTOR. WZZ/AA/ A. Zaa?t 77-7 By 24-14A 4- AT Torney Patented May 3, 1949 2,469,269

UNITED STATES PATENT OFFICE 2,469,269 UNITARY MECHANICAL ACTUATOR, DEVICE William P. Lear, Piqua, Ohio, assignor, by mesne assignments, to Lear, Incorporated, Grand Rapids, Mich., a corporation of Illinois Application April 17, 1943, Serial No. 483,515 Claims. (C. 192-143) 1. 2 This invention relates to a linear actuator unit, end whereby the unit may be directly disposed and more particularly to such a unitary device between a member to be actuated and the Sup comprising a jack screw, a power drive means port. and limit control mechanism therefor. The These and other features, objects and advan present application is a continuation-in-part of 5 tages of the invention will be apparent from the my Patent No. 2,319,463 issued May 18, 1943 and following description and accompanying draw Patent No. 2,403,092 issued July 2, 1946 both as ings, in which: Signed to the Same assignee as this application. Fig. 1 is a top plan view with parts broken While the actuator unit of the present inven away of a linear actuator unit embodying the tion is adapted for general use, it is particularly O invention. applicable for use aboard aircraft for remotely Fig. 2 is a side elevation, with parts broken controlling the position of movable members . away, of the actuator unit illustrated in Fig. 1. thereof. Modern airplanes are provided with Fig. 3 is a left end elevational view of the various movable components such as retractable actuator unit illustrated in Fig. 1. landing gear, oil intercooler doors, cowl flaps and Fig. 4 is a right end elevational view of the wing flaps. Such components are usually hing actuator unit illustrated in Fig. 1. edly mounted on a fixed portion of the aircraft, Fig. 5 is a perspective view of the actuator unit and the position thereof preferably is remotely of FigS. 1 to 4. controllable from a location adjacent the pilot's Fig. 6 is a diagrammatic representation of the Seat or automatically. Recent military experi 20 control circuits and control mechanism actuat ence has shown that hydraulic Controls some ing means for the linear actuator unit. times used for this purpose are not reliable be Fig. 7 is a typical performance curve chart for cause of ready destruction of a hydraulic line due the linear actuator unit. to vibration or being shot away, resulting in Generally speaking, the actuator unit of the many components becoming inoperative. When 25 present invention comprises a linear actuator, mechanical actuators have been used, difficulty such as a jack screw, a power drive means Such has been experienced in installing and properly as an electric motor and electromagnetic clutch, aligning the Sane With the devices to be operated, for effecting the extension and retraction of the and after installation, considerable looseness de actuator, and control mechanism for interrupting velopS due to vibration which detracts from the 30 the energization of the power drive means and stability or even proper operation of the com electromagnetic clutch to disconnect the power ponents. The compact, lightweight, individual drive means from the actuator after a predeter actuator unit for each accessory to be operated mined actuation of the linear actuator in either is therefore more desirable. direction. These elements are all secured to It is among the objects of this invention to pro gether as a unitary device, as by being mounted Wide an actuator unit, including a linear actu 35 on a gear housing containing gearing connecting ator, power drive reans and Control mechanism the drive means to the actuator for effecting ex secured together as a unit; to provide such a unit tension and retraction thereof, and for operating including a jack screw operable by an electric the control mechanism. Mounting means are motor and limit control mechanism operable by 40 provided on the gear housing and on the outer the jack screw for interrupting the energization end of the actuator so tilat, when the unit is of the electric motor and disconnecting it from mounted in position to control the relative angu the jack screw after predetermined actuation of lar displacement of members to be actuated, the the jack screw in either direction; to provide a unit will be disposed directly between such men linear actuator and power drive means therefor bers. If desired, the mounting means may in including adjustable means selectively operable to clude resilient members to facilitate installation interrupt the energization of the power drive and alignment of the unit, and to absorb shocks means and disconnect it from the actuator after and vibrational stresses, as disclosed in Iny co a predetermined movement of the actuator in pending application Serial No. 481,980, fied April either direction; to provide a linear actuator in 6, 1943 now abandoned. The control mechanism cluding a power drive means therefor and an includes switch means for interrupting the en electromagnetic clutch operative upon energiza ergizatigia of the motor and clutch, and these tion of the power drive means to connect, the switch means are actuated by adjustable cams drive means to the actuator; and to provide a operated by the gearing in the gear housing. The compact, foolproof and lightweight linear actu adjustable cams permit the control mechanism ator unit incorporating mounting means at either 5 5 to be set to interrupt the motor and clutch cir 2,469,269 3 4. cu?t after a predetermined movement of the ber may be secured in the aperture of lug d. linear actuator in either direction. The retainer is secured to the body member 3 The actuator may comprise a jack screw in by means of screws 4, and bolts 42 secure the cluding a screw, an internally threaded exten end plate 38 to the body member. sion member, and protecting means for the Screw. 5 The motor 2 is provided with an armature The power drive means preferably comprises an which is mechanically coupled, upon energiza electric motor and an electromagnetic clutch ar tion of electromagnetic clutch 22, to a shaft 45 rangement. The motor is connected to the ac on which is a pinion 46. Pinion 46 engages a tuator through the electromagnetic clutch and pinion 47 on a counter-shaft 48 mounted in the through the medium of gearing disposed in a 10 body member 36 and end plate 38. Another gear housing. The control mechanism prefer pinion 49 on counter-shaft 48 meshes with a large ably includes one or more limit Switches con gear 50 on a shaft 5i extending from the body nected in the energizing circuit for the electric member 36, through the end plate 38 to the cou motor and electromagnetic clutch, and Operated pling member 8. A worm 52 mounted on shaft by means of a limit switch actuator which is con 5 operatively engages a worm gear 53 mounted nected to gearing in the gear housing. on shaft 33 which extends through one wall 55 Referring more specifically to the drawings, of the housing 26 into the gear housing 25, and the unit comprises a linear actuator f0, power is mounted in bearings in housing 25 and limit drive means 5, control mechanism 20, and a gear Switch actuator 34. The cams 3 and 32 are ad housing 25, to which the other elements are Se justably mounted on the shaft 33, on either side cured to effect a unitary compact arrangement. of the actuator 34, and are secured in any de The actuator O comprises a threaded member sired preset adjusted position by nuts 56 and 57. such as a screw i, to the outer end of which is Thereby, the cams may be adjusted to actuate secured a mounting means 2 having an aper Switches 27 and 28 at any predetermined point tured lug 3 which may be Secured either to a during the extension or retraction of linear actu relatively fixed support or to a member movable ator 0. with respect to such support. The screw is It should be understood that the limit switch operatively associated with an extension tube or actuator 34 may be driven in any suitable manner, sleeve 4 which may be internally threaded or and that additional gearing may be included in which may have a nut fixed therein. Suitable 30 the actuator housing to effect any desired speed protecting means, such as dust sleeve i8, may be reduction for cams 3 and 32. For instance, a secured to the mounting means 2 by a screw T, Worm gear could be provided in housing 34 and and is arranged in telescoping relation with the driven by shaft 33, or a pinion on shaft 33 could extension tube to fully enclose the Screw in drive a large gear in housing 34. In any event, all positions of the actuator. The extension tube the invention is not limited to the particular may be secured by a coupling member 8 to gearing arrangement shown. gearing in the gear housing 25 So that, upon ro The end plate 38 of the gear housing 25 is tation of the gearing, the Screw will be either formed with a mounting bracket 60 to which the extended or retracted relative to the tube 4. housing 26 is secured. The limit Switch actuator The drive means 5 may comprise an electric 40 34 is formed with a bracket 6 secured to a wall motor 2 including an electromagnetic clutch 62 of housing 26 by screws 63. A forked bracket brake unit 22 which, upon energization of the 66 at the other end of the actuator 34 is secured motor, is adapted to connect the motor armature to the limit switches 27 and 28 by bolt and nut to gearing in the gear housing 25 and upon de devices 64. A suitable receptacle 65 is provided energization to engage a brake to arrest motion of 45 on the housing 26 to receive connections for the the gearing. A suitable motor and clutch ar limit Switches 2 and 28 and the notor 2. rangement is described and claimed in my Patent The circuit connections for the motor 2 are No. 2,267,114 issued December 23, 1941, and as shown diagrammatically in Fig. 6. A control signed to the assignee of the present invention. Switch 67 is placed at any suitable location, pref A thermal control 23 may be incorporated in the 50 erably adjacent the pilot's seat, and includes a motor as a protection against Overheating thereof. movable contact 68 which may be connected to The control mechanism 20 is disposed in a one terminal of a suitable source of current such housing 26, mounted on gear housing 25, and as the aircraft battery. The contact 68 is adapted includes, in the illustrated embodiment of the in to engage either one of a pair of contacts 69 and vention, a pair of limit switches 27 and 29 having 55 70. A conductor 7 connects contact 69 to one operating plungers 29 and 30, respectively. terminal of limit Switch 27, and the other ter Switches 27 and 28 are preferably of the type minal of Switch 27 is connected to one end of known as micro-switches, whereby relatively large . motor field winding 72 by means of a conduc motor currents may be interrupted by a Small tor 73. A conductor 14 connects the opposite displacement of their plungers. Plungers 29 and 60 terminal of field winding 72 to a junction point 30 are adapted to be engaged by cams 3 and 32 T5, which is connected by conductor 76 to one respectively. Cams 3 and 32 are adjustably side of the operating coil 7 for clutch 22. The mounted on a shaft 33 forming part of limit opposite side of coil 7 is connected by a conduc switch actuator 34. tor 78 to one side of the armature 79 of motor 2, Gear housing 25 comprises a body member 36, 65 and a conductor 80 connects the opposite side of a retainer and mounting plate 37 and an end the motor armature to the other terminal of the plate 38. As will be described more particularly source of electric current. hereinafter, Suitable gearing is disposed in the The other terminal TO of Switch 67 is con gear housing for operating the actuator O and nected by a conductor 8? to one side of limit the limit switch actuator 34. The retainer or Switch 28, and a conductor 82 connects the other mounting plate. 37 is formed with a mounting side of switch 28 to one end of motor field wind means, such as an apertured lug or ear 39, adapt ing 83. The opposite end of field winding 8 ed to be secured either to a relatively fixed sup is connected by a conductor 84 to the junction port, or to a relatively movable member. A bush point 75. Upon movement of the contact ti ing or sleeve 40 of resilient material such as rub 75 into engagement with contact 69, field winding . 2,469,269 5 6 72, the clutch coil 77 and the armature 79 will 1. A linear actuator unit comprising, fin coff be energized to effect connection of motor 2 bination, a gear housing; a linear actuator Se to linear actuator 0 to effect extension of the cured to said gear housing and including a pair linear actuator. Upon a predetermined exten of relatively rotatable and axially extensible Sion of the actuator, the limit switch 27 will threadedly engaged members; an electric mo open to break the energizing circuit for the no tor Secured to said gear housing; a control tor and clutch coil 7, thus deemergizing motor mechanism housing Secured to said gear hous 2 and disconnecting it from actuator f0. Sin ing; gearing in said gear housing connected to ilarly, engagement between movable contact 67 one of said linear actuator members; an elec and the other fixed contact 70 of the switch. 6 tromagnetic clutch secured to said motor and will cause energization of motor 2 and clutch energized, upon energization of Said motor, to 22 to connect the motor to actuator 0 to effect connect said motor to said gearing to rotate retraction of the actuator, and, after a prede said one member relative to the other member termined retraction of the actuator 0, the as for effecting extension and retraction of said lin sociated limit, Switch 28 will interrupt the ener 5 ear actuator when the other said member is held gizing circuit for the motor and clutch to deen from rotation; Switch means in Said control ergize the notor and disconnect it from the ac mechanism housing selectively operable to in tuator. terrupt the energization of said electric notor The clutch 22, including the operating coil and electromagnetic clutch responsive to a pre may well be of the type described and claimed determined actuation of said linear actuator; and in my Patent No. 2,267,44 referred to above. As taeans operatively associated with said gearing described in said patent, this clutch is energized for actuating said switch means. upon energization of the motor to mechanically 2. A linear actuator unit including a gear couple the armature of the motor to the mech housing; a linear actuator secured to said gear anism to be driven. Upon deemergization of the 25 housing and comprising an internally threaded notor and the clutch, the driven clutch plate is extension tube and a screw operatively associ preferably caused to engage a braking surface ated with said extension tube; power drive reans through spring action to effect Substantially in secured to said gear housing; gearing in Said stantaneous stopping of the driven mechanism. gear housing connected to said €xtension tube: Thus accurate positioning or actuation is effect a clutch operative, when energized, to connect ed by remote control. Of course, other forms said power drive means to said gearing to 20 of motors, such as shunt or conpound wound tate the said extension tube for effecting extena motors, or either A. C. or D. C. notors, may be Sion and retraction of said screw when said Screw used; and other types of clutches may be sub is held from rotation; and gontrol mechanis: stituted for the clutch 22. secured to said gear housing and operable by Said Fig. illustrates typical performance curves gearing to interrupt the energization of said for the linear actuator unit of the invention. In power drive reans and effect disengagement of Fig. 7, Such performance curves have been ill said clutch after a predetermined actuation of lustrated over the operating range of the actu said linear actuator. atol', which in the illustrated case may run from 4. 3. A linear actuator unit comprising, in conn Zero pounds axial or thrust load to 500 pounds bination, a gear housing; a linear actuator Se axial load. The curves represent the output cured to said gear housing and including a pair power of the actuator rated in Watts, the cur of relatively rotatable and axially extensible rent in amperes, the speed in inches per nin threadedly engaged members; an electric motor ute, and the relative efficiency throughout the 45 Secured to said gear housing; gearing in Said operating range. It Will be noted that the speed gear housing connected to One of said linear ac decreases substantially as a linear function of tulator members; an electro-magnetic clutch op the axial load, and that the motor current, a eratively associated with said motor and ener series motor in this case, increases as a linear gized, upon energization of said motor, to con function of such load. The efficiency remains nect said motor to Said gearing to rotate said at a substantially constant value over a large one meanber relative to the other member for portion of the operating range. The overall ef effecting extension and retraction of said linear ficiency depends on the design of the unit, its actuator when the other of said members is held gear down ratio, motor Speeds, etc. In practice, from rotation; Switch means mounted on Said efficiencies in the operating range of 10 to 50% gear housing and interposed in the circuit of and higher have been obtained with actuators said electric motor and electromagnetic clutch; of the design illustrated. - cams operatively associated with said switch It will be noted that a compact, lightweight, means and selectively operable to actuate the efficient, linear actuator unit has been provided same to interrupt the energization of Said elec which is admirably well adapted for use in con 60 tric motor and electromagnetic clutch upon a pre trolling the position of individual components determined actuation of Said linear actuator; of an aircraft. The unit occupies less Space than and a shaft mounting said cams and operatively the remotely driven actuation devices here associated with said gearing. tofore used. Additionally, due to the provision 4. A linear actuator unit including, in combina of the adjustable cams and the control mecha tion, a gear housing; a linear actuator secured nism, when it is desired to operate a group of to said gear housing and comprising an internally the actuator units in unison, such Synchronous threaded extension tube and a screw coacting operation may be easily effected by proper ad therewith; power drive means secured to said justment of the cams on the operating shaft. gear housing; gearing in said gear housing con While a preferred embodiment of the inven 70 nected to one of said linear actuator members; tion has been selected for purposes of illustra a clutch operative, when energized to connect tion, it will be understood that the invention may said power drive means to said gearing for be otherwise embodied without departing from effecting relative rotation of said extension tube the principles thereof. and screw to extend and retract said linear actu Wh2t is claimed is: ator when one thereof is held against rotation; 2,469,289 7 control méchanism operable by said gearing to actuate the same to interrupt the energization interrupt the energization of Said power drive of said electric motor and electromagnetic clutch means and effect disengagement of Said clutch upon a predetermined cycle of actuation of said upon a predetermined actuation of Said linear linear actuator. actuator; and means enclosing Said Screw 7. A linear actuator unit comprising, in com throughout its range of movement. bination, a gear housing; a linear actuator in 5. A linear actuator unit comprising, in com cluding a pair of relatively rotatable and axially bination, a gear housing including a mounting extensible threadedly engaged members secured member, a body section and an end Wall; a linear to Said gear housing; an electric motor secured actuator secured at one end to said end wall; 0. to said gear housing; gearing in said gear hous mounting means secured to the other end of said ing connected to one of said linear actuator mem linear actuator; power drive means secured to bers; an electromagnetic clutch operatively asso Said gear housing; gearing in said gear housing ciated with said motor and energized, upon ener connected to one of said linear actuator mem gization of Said motor, to connect said motor bers; a clutch operative, when energized to con 5 to Said gearing to rotate said one member rela nect said power drive means to said gearing to tive to the other member for effecting extension effect extension and retraction of said linear and retraction of said linear actuator when said actuator; and control mechanism mounted on other member is held from rotation; a pair of said gear housing and operable by said gearing Switches mounted on said gear housing and in to interrupt the energization of said power drive terposed in the circuit of said electric motor and means and effect disengagement of said clutch said electromagnetic clutch; a shaft operatively upon a predetermined cycle of actuation of said asSociated with Said gearing; and a pair of cams linear actuator, said linear actuator including a adjustably mounted on said shaft and each oper pair of telescoping sleeves, one of said telescoping atively associated with one of said switches to sleeves being provided with a nut for effecting actuate the same to interrupt the energization o, extension and retraction thereof when said one Said electric motor and electromagnetic clutch sleeve is held from rotation, and a screw oper upon a predetermined cycle of actuation of said, atively associated with said nut, and the other linear actuator. of Said sleeves being Secured against longitudinal WILLIAM. P. LEAR. movement relative to said screw. 30 6. A linear actuator unit, comprising, in com REFERENCES CITED bination, a gear housing; a linear actuator in The following references are of record in the cluding a pair of relatively rotatable and axially file of this patent: extensible threadedly engaged members secured UNITED STATES PATENTS to Said gear housing; an electric motor Secured 3 5 to Said gear housing; gearing in said gear housing Number Name Date connected to one of Said linear actuator mem 1,460,569 Brodesser ------July 3, 1923 bers; an electro-magnetic clutch operatively as 1,654,238 Chandler ------Dec. 27, 1927 Sociated with said motor and energized, upon 1,945,496 Sloan et al. ------Jan. 30, 1934 energization of said motor, to connect said motor 40 1,948,185 Padgett ------Feb. 20, 1934 to said gearing to rotate said one member rela 1993,413 Mellon ------Mar. 5, 1935 tive to the other member for effecting extension 2,114,013 Ball ------Apr. 2, 1938 and retraction of said linear actuator when said 2,118,944 Purdy ------May 31, 1938 other member is held from rotation; a pair of 2,133,161. Colbert ------Oct. 11, 1938 Switches mounted on said gear housing and in 2,150.813 Ball ------Mar. 24, 1939 terposed in the circuit of said electric motor and 2,247,562 Santen ------July 1, 1941 electromagnetic clutch; a shaft operatively as 2,283,476 Waibel ------May 19, 1942 Sociated with Said gearing; and a pair of cams 2,311,682 Murch ------Feb. 23, 1943 adjustably mounted on said shaft and each oper 2,314,019 Shaw ------Mar. 16, 1943 atively associated with one of said switches to 50 2,383,901 Werner ------Aug. 28, 1945