Servo control mechanism
Description
May 10, 1960 J. Rabinow ETAL SERVO original control mechanism presented July 10, 1952 4 Sheets sheets 1 INVENTORS Jacob Rab / Emmett now 0 . Bailey Franco / s H. . S'heparq Jr. (O. @ WMax cam - w May 10, 1960 LAWYERS J. Rabinow
EFAL SERVO original control mechanism presented July 10, 1952 4 Sheets
sheets 3 m M , m 0 r N WHP m W " wm wa GM FIH AR 08 mm weight Q w May
10, 1960 J. RABI NOW ETA - MECHANISM Original
SERVO CONTROL filed July 10, 1952 $ 4 heets sheets 4 IN inventors
Rabinqw E mmefl June Jacob Francis H. 5hepard Balley , JI : ( 0 E . ) .LAWYERS U.S. Patent 2935900 SERVO CONTROL MECHANISM Rahino'w Jacob , Takoma Park, Maryland, Emmett C. Bailey , Riverside , California , and Francis H. Shepard , Jr. , Summit , NJ , assignors to the United States of America, rep! resented by the Secretary of the Navy Original application July 10, 1952 , Serial No. 2? 8076 . Divided and this application June 27, 1957 , Serial No. 671 684
1 Claim.
(
Cl 7; 4-788 ) such as flaps, ailerons, rudders, wings , and the like ,
according to the flight path or changes in the desired flight path . Although
it is possible to place course elements theflight control by direct
mechanical connections to a central control station , links requires a
very heavy and the system becomes unwieldy. Therefore
, it is preferred in the art of using a servo control mechanism
directly associated with each control element during flight and remotely
operated by electrical signals coming out of the central control
station . Command
signals to electrical signals that emit from the central control
station can be started in the original release site or at any other
point remote from the missile .The
present invention relates to a servo control mechanism of this type ,
which uses air slippage or missile ship feeding a windmill, air motor ,
or an air turbine motor or servomotor as primary positioning control elements of the course as the central control station desiredby . Since it is generally necessary to move the various elements coursecontrol in one of two directions, oneTherefore, it is an object of the present invention to provide a windmill or air powered servo motor meca .msm .Another
object of the present invention to provide a windmill or air motor
driven servo mechanism that uses an electromagnetic clutch , for
selecting two directions from the motor drive in response to a
unidirectional electrical control signal .Another object of the present invention is to provide a low inertia magnetic clutch investment . 1
Another object of the present invention to provide a low inertia
magnetic clutch operating in response to continuous unidirectional input
unit for supplying three, put conditions : two-way drive output and an
output condition of neutral or zero.Other
objects and many of the attendant advantages of this invention will be
readily appreciated as the same becomes better understood by reference
to the following detailed description when considered in connection with
the accompanying drawings in which:. Figure
1 is an end view of a wing of an aircraft or missil mechanism having a
servo power supply air by way of example , the present invention mounted
or under it , i .. 2a
is an enlarged view of the front of a servo driven mechanism exemplary
air pressure : ent invention , shown partly in longitudinal section ;. 2b is an enlarged view of the portion after the servo mechanism shown in Fig . 2a shows the longitudinal section partially'in ;
. Figure 3 is a cross sectional view of the mechanism shown in Fig . 2a, taken along . line 3-3 thereof ;. Figure 4 is a cross sectional view of the mechanism shown : in Fig . 2a, taken along line 44 thereof , and Figure i . 5 is an isometric view of a spider used in the magnetic clutch shown in FIG . 2A.Referring
particularly to the view partially sectioned longitudinally of the
servo control mechanism embodiw reverse clutch is associated with the
air motor in the present servo control mechanism for deriving from the
motor unidirectional two directions of movement. Engine
power as controlled by the reverse clutch is applied to an actuator in
turn coupled to a current control element to move and position the
element in one of two directions as desired . In
the preferred embodiment of the present invention , the clutch
operation is poor between three conditions , a condition providing power
transmission in one direction, the second transmission providingpower
condition in the opposite direction, and the third condition being
neutral which
engine power is transmitted to the actuator , in obtaining the
three-way action above is preferred to employ a magnetic control on the
clutch properly sig sensitive signals leaving the station flight control
. also ,is
associated with one actuator means operated followup electrical signals
so indicate to the central control station of the actuator position and
hence the control element of course, to allow comparison of the actual
position of the control element golf required by the station flight control center. The
signals output from the central control station therefore clutch
magnets operate to effect movement of the control course in one
direction or the other as needed , until the monitoring signal indicates
operator controlled that
the current control element is the required position , after which the
clutch is placed in its neutral condition mentioned above so that no
more energy is transferred from the motor to the actuator ,tion of the present invention illustrated in FIGS . 2a and 2b , the device comprises three primary secti'onsz ' windmill or fan 10 , the magnetic clutch 20 , and actuator 80 . *
Windrnill 10 is mounted for axial rotation operation with respect to
the main housing 97 and is connected to the rotatable drive shaft 11
which terminates in a stub shaft 13 supported in a reduced diameter
annular friction bearing 14. As
shown in the drawing, the rearward portion of the axis 11 is
longitudinally slotted at 12 to provide a gear unit for the magnetic
clutch assembly described below .Disposed
around the annular shaft 11 and at each end thereof two substantially
identical eleetro : magnet assemblies , shown as comprising the annular
coils -21 and 21a housed inside the main annular body mem bers 22 and
22a and complementary body members 23 and 23a ring . The
members of the body are formed from magnet temporary magnetic material
such as soft iron , and lots 25 and 26 of a magnet and another 25a and
26a of ring magnet pole pieces provide it apart annular air spaces : 27 and 27a , respectively. To
completely isolate 97 homes and other portions of the mechanism of the
effects of magnets when activated, the magnet body members may be
separated therefrom by non- permeable , such as 24 and 24 rings ,
annular ring 28 . And bearingcaps'29 ;Support
between the sets of bearings electromagnet 31 and 31a, and around a
portion of the drive shaft 11 is the rest of the set V magnetic clutch .
The focus of this meeting is the spider 30 which ednp PPPO nm 3 Strand 36 . 3Spider
are made by two sets of planetary gear systems , one supported
between the discs 32 and 33 and the other supported between the discs 33
and 34. The gear system supported between the discs 32 and 33 is best shown in the view - the'cross - s'ectional , Fig . 3
where it'islseen two intermediate gears 46 and 46a mesh with the
splined portion 12 of shaft 11 through the cutout sections 35 and 35a in
the central cylindrical portion 38 of the spider. And these gears meshing respectively with gears 40a and 40, which in turn mesh with the teeth of an internal ring gear 47 . Considering the details of the individual sets of gears 40, 40 , referring to the gear unit 40 ' as an example of the other. Gear
40 which meshes with the ring gear carries a roller 47 with the same
pitch diameter 41, and this unit is rotatably carried between the disks
32 and 33 of the spider in a short shaft 44 which enters the holes 45 ( Figs. 2a and 5) to these discs and is secured therein by any suitable , such as appropriate adjustment screw 45a . The roller gear 40 and its associated passage diameter are spaced discs 32 and 33 by thrust rings 42 and 43. The other gears 46 and 46a are also rotatably mounted between the discs 32 and 33 of the spider. Around
this gear set is the ring gear 47
previously mentioned , and is secured
thereto by screws 50 or the like, is an annular ring 49 of magnetic
material which is temporarily placed adjacent the pole pieces 25 and 26 magnet 21, 22, 23. Crown
magnetically insulating ring 47 magnetically permeable annular spacer
49 is non-magnetic material 48 , which also provides a bearing pitch
diameter roller 41 .From the above structural description taken with reference to FIGS . 2a,
3 and 5, we can see that the instant planetary gear arrangement works
in conjunction with the temporary magnet 21, 22, 23 as follows: When the
aforesaid magnet is not energized the magnetically permeable ring 49 is
not attracted towards
the pole pieces of the same and therefore , along with the magnetically
insulating spacer 48 and the ring gear 47 associated therewith , are
free to rotate relative to the magnet. Therefore,
when the shaft 11 is rotated by its driving windmill or air motor 10,
which causes intermediate gears 46 and 46a, which mesh with the splined
portion 12 of shaft 11 to rotate about their respective turn axis similarly rotate the gears 40 and 40a . Since
ring gear 47 is now free to travel on the gears 40, 40 , 46 and46a in
response to rotation of these planet gears , the planet gears are
stationary in their orbits. However, the magnet energ'ization 21, 22 , 23, magnetically permeable ring 49 is attracted to the pole pieces 25, 26and is there against rotation , thus stopping the movement of the crown 47 . Under
this condition, the planetary gears 40 , 40a , 46, 46a and are forced
to travel in their orbits around the sprocket 47 and the drive shaft 11 ,
thus rotating the spider 30 on which are carried the axes of the planetary gears .Referring now to the gear assembly ananular located between disks 33 and 34 of the spider with particular reference to FIGS . 2a
and 4 - , will see that this system comprises two planet gears 60 and
60a - Hing month both toothed section 12, the drive shaft 11 through the
openings 36 and 37 in the central portion 38 of the spider, and with the gear teeth of the inner ring 67 . The
construction of this gear assembly is substantially identical to that
described for the other set of gears with the exception of the omission
of planetary gears mad . The
ring gear assembly comprising the ring gear 67, the magnetically
insulating separator 68, and the magnetically permeable ring 69 afiixed
all together as by means of screws 70 , also is substantially identical
to that described above. It
can therefore be seen that when the shaft 11 is driven by the windmill
10 , and when the magnet 21a, 22a, 23a is not energized , the rotation
of the gears 60 and 60a causes ring gear 67 to rotate relative to the
magnet and to travel on the planetary gears 60 and 60 bis . However,
when activated this magnet , the rotation of the ring gear 67 is
stopped and the planetary gears 60 and 60a are caused to orbit around
the drive shaft and sun gear 11 which carries with it the spider 30 on
which are mounted .From
intermediate gears 46 and 46a are interposed in the first planetary
gear set is described and are omitted in the second set described , it
is apparent that when the ring gears 47 and 67 are therefore free to
rotate relative to their respective magnets in response the
rotation of the drive shaft 11, which rotate in opposite directions,
and similarly the orbital motions of the planet gears of the two sets
are in opposite directions when their respective ring gears are secured
against rotation by activation of their respective magnets. Therefore,
when activated either spider magnets 30 remains stationary , and when
the magnet 21 , 22, 23 is energized and magnet 21a, 22a, 23a is not
energized , spider 30 is rotated on its bearings 31 , 31a one
direction, and when the magnet 21a, 22a, 23a is excited by the magnet
21 , 22,23 -energized , the spider 30 is rotated on its bearings 31 ,
31a 0pposite direction .Drive shaft 81 , shown in FIGS . 2a
and 2b, which is threaded at 84 is fixed to the spider 30 by means of
the key 82 and the pin 83 for rotation therewith hearing 85 . Traveler
axis or internally threaded nut 86 is threaded onto the actuator shaft
81 and secured against rotation by the entry of key 87 in slot 88 formed
in the axis of
travelers. If desired, a ball bearing spindle return type low friction can be used by the actuator and the axis of the travelers. Thus,
after rotation of the spider 30 actuator shaft 81 is rotated therewith,
and the shaft or the nut 86 threaded onto the drive shaft 81 is caused
to travel axially along the actuator shaft 81 at a direction or the other depending on the direction of rotation of the spider 30 and the drive shaft 81 . Traveler shaft 86 which terminates at the eye 89 can be atlixed a fork or crank 103 as shown in Fig . 1 to place an eleven , spoilers , element . Vator
, or the like 102 when the servo control mechanism is mounted on the
bottom surface of a missile or aircraft wing 101, and through the ball
joint 94 . Aflixed to and shown in Fig . 2b
as Traveler depending shaft 86 is an electrical contact roller 90 moves
spanning slide wire potentiometer 91 as the shaft 86 . I
This variable potentiometer is used for the stated purpose of providing
an electrical signal indicative of actual or alleged traveling axis
position of the control element and the signal thus obtained is fed back
to the control center ' stationt 0 to allow a comparison between the current position of the control element desired and actually had . All
electrical connections between the missile and aircraft and servo
control mechanism instant , as may be necessary to perform the operation
of the electromagnets and the instantaneous position tracking
potentiometer , can be obtained through the cable 96 ."
In operation of the servo control mechanism described hereinabove , it
is contemplated that the blade can be mounted on air missile or aircraft
, such as on the lower surface of a wing , of which the mill wind or fan 10 derives power operation . This
power is transmitted from the windmill through the drive shaft 11 and
the spider 30 to the actuator shaft 81, the latter is coupled to inturn
traveler shaft 86 to move the same axially in one of two directions as required by the central control station . Correct positioning of the travelershaft 86 is effected through the magnetic clutches associated with . spider
30 which operates in response to signals derived from the central
control station with the required variable is a potentiometer associated
with the output shaft of the traveler whose central control station is
varied according to the position occupied by this axis.The
specific embodiment described above of the present invention is
presented by way of example only to facilitate a clear understanding of
the invention. Obviously many modifications and variations of the present invention are possible in light of the above teachings. Is
therefore to be understood that within the scope of the appended claims
the invention may be practiced otherwise than as specifically described
.What is claimed is:A
transmission mechanism comprising a rotatably mounted spider having a
sleeve unitary annular pair of planetary gears 21 carried by and
rotatably mounted on said spider in spaced relation to each other, means
that includes at least three members disk
formed integrally with said sleeve rotatably mounted on said planet
gears in said spider mutually spaced from each other, a pair of ring
gears carried freely on said planet gears , respectively , and having a
fixed permeable ring thereto,
means including a shaft rotatably mounted within said sleeve and which
cooperates with each of the planetary gears to drive the planet gears to
rotate the ring gears in opposite directions, and an electromagnetic
brake which cooperates the
permeable ring on each ring gear , said brake including an annular coil
and a pair of mutually spaced annularv pole mounted in said sleeve and
secured with respect thereto and to be effective for said coil to:
selectively engage and application longitudinal
braking force to said activation ring permeable to allow said coil and
said retard rotation of said ring gear , the selective retention of a
ring gear relative to the other ring gear causing the planet gear
cooperates with the the
same orbit , resulting in the rotation of said spider , either in one
of two directions , depending on which ring gear is held against such
rotation .
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