US2482464A - Electrical jack and control means - Google Patents

Description

J. E. CHAPMAN ELECTRliCAL JACK AND CONTROL MEANS Sept. 20, 1949.

2 Sheets-Sheet 1 Filed Sept. 25, 1942 Manual". JAMES E. CHAPMAN,

(Incl-neg;

Sept. 20, 1949. J. E. CHAPMAN ELdCTRICAL JACK AND CONTROL MEANS 2 Sheets-Sheet 2 Filed Sept. 25, 1942 31wcntor Gttomeg Patented Se t. 20, 1949 UNITED STATES PATENT. OFFICE James E. Chapman, Los Angeles, Calif" assignor to The Garrett Corporation, Airesearch Manufacturing Company division, Inglewood, Calm, a corporation of California Application September 25, 1942, Serial No. 459,731

My invention relates we power jack or extensible strut having particular utility in the operation of movable parts of aircraft. It is an object Claims. (Cl. 192-142) of the invention to provide a simple and compact device having a motor body which is ordinarily attached to a stationary part and an extensible 4 thrust bar which may be connected to the part vide a simple jack of the character described in the foregoing having novel means for operatin a control member in accordance with the move- .ment of the thrust-bar. This control member unay be associated with or embodied in a switch mounted directly upon the motor casing of the device,.wherein the control of the motor is correlated with movement ofthe thrust bar through a prescribed range of movement.

A further object is to provide an electric jack 1 of this character which is slender in form and therefore may be located in spaces of comparatively small size. By slender I intend to convey the meaning that lateral extension of the motor body is maintained at a minimum.

A further object of the invention is toprovide a power operated jack having a reduction gear so formed and in such cooperative relation to the motor and to the driven parts that slenderness and compactness are achieved.

A further object of the invention is to provide a jack wherein a motor driven part operates a screw which in turn reciprocates through a path of movement a traveler arranged so that it will actuate switch means employed in the control of the 'motor of the device. Suchswitch means may be of any desired character and may cooperate in control circuits in diiierent ways, so long as the ultimate effect thereof is to produce a control of the operation of the motor in accordance with 'difierent positions of the thrust bar of the Jack. For example, the switch means may be merely a limit switch, but is preferably a series type multiple switch capable of use in the controlcircuits and system disclosed in the copending application of Hannon, Serial No. 430,949, filed February 14, 1942, now Patent No. 2,314,937.

Further objects and advantages of the invention 2 may be brought out in the following part of the specification.

Referring to the drawings which are for illustrative purposes only,

Fig. 1 is a longitudinally sectioned view of the jack.

Fig. 2 is an enlarged cross sectional view taken as indicated by the line 2-2 of Fig. 1.

Fig. 3 is a fragmentary section taken as indicated by the line 3-3 of Fig. 2.

Fig. 4 is an enlarged fragmentary sectional view taken as indicated by the line 4-4 of Fig. 1, to show a plan view of the switch mechanism.

Fig. 5 is a partly sectioned view showing an alternative form of switch mechanism for use in the .lack.

Fig. 6 is a slightly enlarged cross section taken as indicated by the line 66 of Fig. 5. I

Fig. 7 is a plan view of the series switch device shown in Figs. 5 and 6.

The preferred embodiment of the invention shown in Fig. 1 includes a small reversible motor.

It] included within a slender casing II which rotatably. supports a driven member [2 having threaded engagement with a thrust bar It which will move axially in response to rotation of the member I2. I

The motor ID has a rotor I 4 which drives the A member-12 through a novel arrangement of gears i5 disposed in a position surrounding the inner portion of thethrust bar. [3 when this thrust bar is in retracted position as shown in Fig. 1. The driven member I2 is arranged to rotate a screw 16 which moves a traveler I! back and forth through a range of movement in accordance with the movement of the thrust bar I3 through different positions in its relatively larger range of movement. The traveler I1 cooperates or forms a part of a switch device S which is connected into electrical circuits associated with the motor I. The motor circuit forms no part of the presentinvention, and although the switch device S may be a simple limit switch for stopping the motor when the thrust bar 13 approaches the end of its range of movement, the switch device is so formed that it will cooperate in a control circuit suchas disclosed in the copending application of Hannon, Serial No. 430,949, previously referred to.

The motor Ili is built into the cylindric section 18 of the casing II and includes field pieces l9. Thecylindric section It is clamped between a cap 2| and the front section 22 of the casing H 'by means of screws 20. The cap 21 has a pro- .iection 23 with an opening 24 therein whereby the rear end of the casing II is connected to a stationary part. 7

Within the section 22 there is a radial wall II which supports a bearing 26 in which a tubular member 26' is rotatable. The left or rear end of the tubular member 26' is rotatably supported in a bearing 21 carried by the cap 2|. The tubular member 26' comprises the hollow shaft of the rotor I4 and supports thereon the motor armature Z8 and the commutator 29, both of which parts are diagrammatically indicated. The hollow shaft 26 is of such size that the threaded thrust bar l3 may extend thereinto when it is retracted as shown in Fig. 1.

The rightward end of the casing section 22 h threads 30 to receive an end member 3| which ha a projecting tubular portion 32 carrying b rings 33 which'support the driven member II. The bearings 33 engage a threaded tubular porticn 34 of the driven member I2 and support the same for rotation on the axis of the casing {The driven member |2 includes a circular plate $35 at the inner end of the tubular portion 34, this !plate 35 supporting a short cylindrical section 36 comprising an internal gear 31 and an external gear 38. The rightward end of the hollow shaft 25' projects beyond the bearing 26 and has a drive pinion 39 formed thereon. This drive pinion engages planetary gears 40 which are supported in outward relation relatively thereto by pins or axles 4| which are carried by a ring 42 supported for rotation around the axis of the shaft 26' by a ring bearing 43. A ring gear 44 is secured in the casing section 22 in a position adjacent the ring bearing 43, this ring gear engaging the outwardly directed teeth of the planetary gears 40 so that when the motor In is operated to rotate the pinion 39, the planetary gears 40 will be caused to roll around the interior of the ring gear 44. Second planetary gears 45 are rotatably supported on the axles 4| and are directly connected to the planetary gears 40 so as to be rotated thereby. The second planetary gears 45 are of a different diameter than the first planetary gears 40, and the teeth thereof engage the internal gear 31 of the driven member i2. This difference in diameter of the first and second planetary gears 40 and 45 results in a slow rotation of the driven member I! as the planetary gears 40 roll through their circular path of movement within the internal gear 44. This reduction in thespeed at which the member I2 is driven as compared to the motor speed is of course accompanied by a corresponding increase in torque applied to the driven member II. The threaded thrust member l3 has a head 45 fixed thereon having an opening 4'! to receive a bolt or pin carried by the part which is to be moved by the jack. Accordingly, rotation of the threaded thrust bar I3 is prevented, and as the member I! is rotated, the thrust bar I3 is caused to move axially, thereby changing the distance between the openings 24 and 41 and producing relative movement of the parts to which the motor casing l and the head 46 are respectively connected.

The screw I6 is supported on the casing section 22 by bearings 48. A small gear 49 is fixed on the screw l6 near the front end thereof, and the lower portion of this gear 49 projects through an opening 50 in the casing section 22 into engagement with the external gear 38 of the driven member l2, so that the shaft IE will be given a rotation corresponding to the rotation of the member I2, and the traveler H which comprises a nut in threaded engagement with the screw l8 will have movement along the screw l4 co to themovement of thethrustbar llinaxialdireetion as the driven member I2 is rotated.

AsshowninFigs.2and4,aIu|debarl| is secured in parallel relation to the screw II by screws 52, and on the outer face of this guide bar 5| a wall 53 of insulating material is mounted. Spaced openings 54, through the guide bar II and the wall 53, receive thrust pins 55, the outer ends of which engage spring contacts Ii. which are secured to the outer face of the wall 53. Each of these spring contacts 56 has a laterally extended supporting base 51, positioned so as to be engaged by the movable end of the preceding contact 65, whereby a series arrangement of these switch members is obtained. Referring to Fig. 3, a contact 53 is disposed at the leftward end of the switch assembly, this contact being engageable by the first or left hand switch 5|. Progressing rightwardly through the arrangements of switches, it will be noted that each succeeding switch 55 engages the base 51 of the preceding switch. a

The traveler has fingers 53 to engage the upper and lower faces of the guide bar 5|, as shown in Fig. 2, and the traveler I! has a cam faced toward the guide bar 5| and having sloped ends 6|. This cam it forces either one or two of the pins '55 outward, depending upon the position of the cam in, thereby lifting corresponding switch members out of engagement with the cooperating switch contacts formed by the base portions II of other contacts 56, or the end contact 53, as

4 shown, for example, at 56' in Fig. 4. These seriesarranged switches cooperate with the circuits of a motor controlled system such as shown in said copending application, Serial No. 430,949, Patent No. 2,314,937, previously herein set forth. The jack is therefore adapted for uses under conditions wherein a part is to be operated or controlled from a remote position.

In Figs. 5, 6, and 7 I show an alternative construction wherein screw threads Ii, analogous to the screw l6 of the switch device 8, are formed on the tubular driven member I! which is analogous to the driven member I! shown in Fig. 1. The jack shown in Fig. 5 embraces the motor casing II and the parts included therein, as will be indicated by the duplication in Fig. 5 of numerals employed in Fig. 1. The changes in the structure are as follows. The front end cap 3| is replaced by an end cap 3|" having an elongated tubular wall 32 to support the driven member 12'. This wall 32' has an opening 02 alon a side thereof across which the switch plate ll, of nonconductive material is supported. A guide bar 5| is supported on the inner face of the switch plate 63 in parallel relation to the axis of the driven member l2 and thrust pins 55 are extended through the switch plate and the guide bar 5| as shown in Figs. 5 and 6. The inner ends of the pins 55 are positioned so that they will be engaged by a cam surface 60 formed'on an internally threaded traveler H which engages the screw threads |i', so as to be moved lengthwise of the driven member I! as the result of the rotation of this driven member l2, the movement of the traveler being proportionate to the movement of the thrust bar l3 in consequence of the greater lead of the screw threads formed on the thrust bar I3.

So as to be confined by a cover 65, switch parts 56a, 56b, and 58a are secured on the outer face of the switch plate ii. The switch part Ila is a stationary contact which is engaged by the swingable end of a leaf switch 56a as shown at the left of Fig. 7. This leaf switch 56a has a lateral extension 51a, and in series arrangement additional leaf switches 56a are arranged in rightward consecutive order along the switch plate 63, with a simple leaf switch 561) at the rightward end of the switch plate 63. These leaf switches 56a and 56b are arranged over the heads of the thrust or lift pins 55', whereby the leaf switches will be lifted in consecutive order as the traveler l 'l' is moved from end to end of its range of movement.

I claim as my invention:

1. In a power jack of the character described, the combination of a motor having a rotor; an externally threaded thrust bar supported for axial movement; an internally threaded driven member supported for rotation, the threads of said driven member engaging the threads of said thrust bar; a connection to drive said driven member from said rotor at a reduced speed; an external screw on said driven member; a traveler in threaded engagement with said external screw so that it will be moved through a path of movement in response to rotation of said driven memher; and switch means for control of said motor disposed contiguous to said path of movement so'as to be actuated by said traveler in timed relation to the movement of said thrust bar.

2. In a power jack of the character described, the combination of: a support having spaced bearings; a tubular member rotatably carried by said bearings, said tubular member having an internal thread and an external thread; motor means to rotate said tubular member; a thrust bar extending within said tubular member and having threads to engage said internal threads of said tubular member so that rotation of said tubular member will cause an axial movement of said thrust bar; a traveler having thread means to engage said external threads of said tubular member so that rotation of said tubular member will cause movement of said traveler through a short distance as said thrust bar is moved through a'relatively long distance by rotation of said tubular member; and switch means for controlling said motor comprising at least two switches and actuators for said switches disposed along the path of movement of said traveler so as to be engaged and operated by said traveler in a prescribed relation to the diflerent positions into which said thrust bar is moved by rotation of said tubular member.

3. In a power jack of the character described, the combination of: a support having spaced bearings, a member rotatably carried by said bearings, said member having a first screw thread and a second screw thread; motor means to rotate said member; a thrust bar having threads enga 1118 said first threads so that rotation of said member will cause an axial movement or said thrust bar; a traveler having thread means to enmesaidsecondthreadsotsaidmemberso that rotation of said member will cause movement of said traveler through a short distance as .said thrust bar is moved through a relatively long 4. In a power jack of the character described, a

combination of a motor; an externally threaded thrust bar supported for longitudinal movement; a threaded driven member supported for rotation, the threads of said driven member engaging the threads of said thrust bar; connecting means be tween the motor and driven member; a second screw on said driven member; a traveler in threaded engagement with said second screw so that it will be moved through a path of movement in response to rotation of said driven member; and switch means for control of said motor, disposed contiguous to said path of movement so as to be actuated by said traveler.

5. In a power jack of the character described, the combination of: a motor having a rotor; an externally threaded thrust bar supported for axial movement; an internally threaded driven member supported for rotation, the threads of said driven member engaging the threads of said thrust bar; a connection to drive said driven member from said rotor; an external screw on said driven member; a traveler in threaded engagement with said external screw so that it will be moved through a path of movement in response to rotation of said driven member; and switch means for control of said motor, said switch means including a series 01' movable members disposed contiguous to the path of movement of the traveler so as to be successively actuated by said traveler in predetermined relationship to the movement 01' said thrust bar.

JAMES E. CHAPMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 882,878 Ford Mar. 24, 1908 1,245,574 Dean Nov. 6,1917 1,325,010 Evarf Dec. 16, 1919 1,330,790 Dean Feb. 17, 1920 1,967,045 Wehmeyer July 17,1934 1,979,162 Lansing Oct. 30, 1934 2,093,325 Lansing Sept. 14,1937 2,259,437 Dean Oct. 21,1941 2,279,220 Baum Apr. 7, 1942 2,283,476 Waibei May 19, 1942 2,307,317 Konig Jan. 5,1943

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