US2405047A - Sight control mechanism - Google Patents

Description

July 30, 1946. w. H. NEWELL SIGHT CONTROL MECHANISM Filed May 4, 1943 4 Sheets-Sheet 1 INVENTOR WILLIAM H.NEWELL ATTORNEY UH W! 33. GEUMHHHJAL lNbHiUIViLN lb.

July 30, 1946. w. H. NEWELL SIGHT CONTROL MECHANISM 4 Sheets-Sheet 2 Filed May 4, 1945 lNV ENTOR ILLIAM H. NEWELL VATTORNEY SEQYCH H09" 56. ULUMUMLM HOIRUPHLN m5 July 30, 1946. w. H. NEWELL SIGHT CONTROL MECHANISM 4 Sheets-Sheet 3 Filed May 4, 1943 INVENTOR WILLIAM HNEWELL ATTORNEY gfgp 3 M um I Hum [.15 h):

y' 1946- w. H. NEWELL ,047

S IGHT CONTROL MECHANISM Filed May 4, 1943 4 Sheets-Sheet 4 glauzm I 43 g llllllllllllllIIIIIIIIIIIIIIIIHIIIIIII INVENTOR WILLIAM H.NEWELL ATTORNEY GEOMEIRlCAL lusmumw is.

Patented July 30, 1946 search Rom SIGHT CONTROL MECHANISM William H. Newell, New York, N. Y., assignor to Ford Instrument Company, 1110., Long Island City, N. Y., a corporation of New York Application May 4, 1943, Serial No. 485,585

12 Claims. (01. 33-49) This invention relates to the field of gunnery and particularly to the control of the movement of a sighting device such as a telescope while tracking a target and of its angular position relative to a gun.

Ideally, automatic means move a sighting device, herein termed a sight, at a pro-per rate to compensate for the relative movement of a target and thus to maintain the target in the field of view of the sight, and at the same time supplemental means determine and introduce the sight deflection angle, that is, the lead angle of the gun relative to the sight which is a function both of the range and of the rate of movement of the sight.

The invention is herein disclosed as applied to the control of the position of the sight in azimuth and of its training rate. In such application a power device drives a training table on which the sight is mounted relative to a fixed circular rack, and the effective rate is to be regulated so as to comport with the rate of relative movement of the target. The purpose of the invention is to provide mechanism of a type that will enable the operator accurately, smoothly and simply to introduce corrections as errors develop.

It is a characteristic of the invention that the operator directly and temporarily effects an acceleration of the sight to correct for an accumulated error, and that this acceleration is converted to a modification of the eifective rate of the power device. As preferably embodied the invention contemplates a variable speed device the output of which effects the movement of the sight at a rate which is the final result of accelerations introduced by the operator. Considering the bearing of a sight, although it will be apparent that the invention is equally applicable to the control of a sight in elevation, the rate at which the bearing is automatically generated is suitably represented by the output of a variable speed device the rate member of which is under the direct control of another variable speed device the rate member of which is adjusted by the operator. Thus the quantity introduced by the operator produces a change of rate of the first variable speed device an amount depending upon the value and duration of the quantity, and the output of the first variable speed device is accelerated.

To effect a correction in the position of a sight in addition to correcting the rate of movement, the invention also contemplates introducing the change of rate of the first variable speed device directly into its output. Also it is contemplated that the movement representing the quantity introduced by the operator may be introduced directly into the generated movement in order to give an immediate indication of the fact and direction of a correction, thus enabling the operator to check on an action in anticipation of the modified output of the generating mechanism the appearance of which after the operator introduces a movement representative of acceleration involves an appreciable period of time.

While theoretically the source of power which drives the power elements of the variable speed devices may drive the sight, in practice it is desirable to employ an additional servo motor for this purpose. In such case the relay for controlling the servo motor is differentially controlled by the output of the position generating mechanism and by the position of the sight. In other words the output of the differential represents the error or disagreement between the generated position and the response of the servo motor.

This relay may be of the so-called pneumatic type in which the control member of the servo motor is spring biased to central or neutral position and is operatively connected to a pneumatically controlled movable member, such as a diaphragm or a piston, that has normally balanced air pressure on both sides but the balance of which is under the control of a valve member that is connected to be actuated by the output of the differential. Also there may be provided a suitable pneumatic impulse mechanism through which the movement directly caused by the operator acts upon the control member of the servo motor and anticipates the arrival of the effect of the movement through the generating mechanism.

In case the mechanism is to be used for training control on board ship it is desirable to maintain a constant indication of a fixed meridian or other azimuth datum. It is contemplated that for this purpose an azimuth gyroscope may be used so mounted as to effect a differential action in control of the servo motor relay.

The invention also contemplates means for utilizing the rate of generated movement to determine and introduce the sight deflection angle, means to control the acceleration of the servo motor, and other features which will more fully appear from the following description of the illustrated embodiments of the invention.

Referring now to the drawings, Fig. 1 is a diagram representing one simple embodiment of the invention.

Fig. 2 is a similar diagram of a modified embodiment of the invention.

Fig. 3 is a similar diagram of another modified embodiment of the invention.

Fig. 4 is a sectional detail of the part of the pneumatic control system that is carried on the base with the gyroscope in the construction of Fig. 3.

Fig. 5 is an enlarged sectional detail of one of the chamber members of the impulse means.

Fig. 6 is a diagrammatic representation of the problem to which the mechanism of Fig. 3 is suited.

Fig. 7 is a diagram representing a modified form of connection between the impulse means and the motor control.

Fig. 8 is a section on line 8-8 of Fig. 7.

Fig. 9 is a view similar to Fig. 8 with some of the parts displaced.

In the design of apparatus shown in the drawings a sight I is mounted on elevation trunnions bearing in uprights or legs 2 fixed on a training table or mount 3 mounted for rotation inside a fixed, circular, peripheral rack 4. A hand controller 5 which has a handle on one end and a gear segment on the other, is pivoted on a cross plate connecting the legs 2 on an axis perpendicular to the training mount. Its toothed end meshes with a rack 6 which has on one end a ball carriage of a variable speed drive I.

Adjacent the variable speed drive I is a second variable speed drive 8. These variable speed drives are of the two ball integrator type consisting of a power driven disc Ia and 80., respectively, a rate member lb and 817, respectively, which is a ball carriage and two balls therein, and an output roller I and 80, respectively. A constant speed motor 9 is geared to drive the discs Ia and 8a.

This drive mechanism is operative to drive an output shaft II) that functions as a primary movable member to produce or control the angular movement of the mount 3 and hence to train the sight I. The output roller 7c is geared to shaft II which has a pinion I2 engaging rack I3 that carries ball carriage 8b. Shaft I 0 is mechanically operated by the output roller 80.

Taking a second as the unit of time and a radian as the unit of angular motion of the shalt If), it is evident that the position of the rate member of the variable speed drive 8 represents radians per second, and that the position of the rate member of the variable speed drive 1 represents rate of change of rate, that is, radians per second per second. In other words the first represents velocity or rate of change of position and the second represents acceleration or rate of change of velocity. Therefore when the operator moves the controller he changes the rate of acceleration and the resulting acceleration is integrated through the period of time that the operator holds the handle oif-set so that the movement of the output roller 1c represents change of rate of change of position; and the product of the rate represented by the position of the member 8b multiplied by time represented by the rotation of disc 8a is change of angular position of shaft I0. Therefore it will be seen that a movement of the controller 5 modifies the rate of the shaft Ill, and a much smoother and more exact control of the movement of the shaft I0 is thus obtained than is possible by applying the movement introduced by the operator directly to the rate member 8b.

As above stated the movement of the shaft I0 effects the training of the mount, and since it is the accumulation of an error which apprises the operator that a change in rate is needed, it is desirable to remove the accumulated error coincident with the effecting of the change of rate without requiring an overcorrection of the rate. To bring this about the movement of the output roller 1c is added to that of the output roller 80, and the shaft I0 is thus set ahead or back depending upon the direction of movement of the controller 5. As shown, the shaft II is geared to a shaft I4 that is geared to one of the inputs of a differential I5, the output roller being connected to the other input, while the output of the differential drives shaft I 0. Thus the change of rate of change of position is introduced directly into the differential I5 to effect a change of position of the shaft Ill.

Since the complete effect of movement of the acceleration roller 1c is not instantaneous upon the movement of the rack 6 through the controller 5, it is desirable for the purpose of checkin to have the rack 6 act directly upon the shaft I0 so as to give an immediate indication to the observer through the telescope that the controller has been moved and the direction of the ensuing correction. To accomplish this it is suitable to introduce the movement of the rack 6 directly into the position of the shaft II). This may be done by a second differential I6 to one input of which the rack 6 is connected by shaft I'I, while the output of differential I5 is connected to the other input and the shaft I0 is connected to the output.

In the form shown in Fig. 1 the shaft I0 is connected directly to drive the mount 3. This assumes sufficient power in the motor 9 for the purpose. As shown a training pinion I8 meshes with rack 4 and is carried on the end of a shaft bearing in a bracket I9 and having on its upper end a gear 20 that is driven from the shaft I0. Specifically a counter shaft 2| which is geared to shaft I0 is operatively geared to drive gear 20 through shaft 22 and drive pinion 23.

The position of shaft I0 and hence the hearing of the sight I is transmitted through a shaft 24 that is geared to shaft 2| to a transmitter 25 of a synchronous electric transmission system which in turn transmits it to a gun (not shown). Means are also provided to determine and add to the transmitted value the sight deflection angle, that is, the angle between the sight and the gun. This angle is the product of the rate of change of bearing and range or time of flight of a projectile which is a. function of range.

As shown a multiplier 26 is provided, one input member of which is set by the shaft II through pinion 21 and rack 28 so that it agrees with the setting of the ball carriage 8b and hence represents rate of change of bearing, and the other input member of which is set by handle 29 to introduce time of flight which simultaneously is shown on dial 30 that may alternatively be graduated in corresponding values of range. The output of the multiplier 26 actuates shaft 3|. The movements of shafts 24 and 3I are combined in differential 32 the output of which is connected to drive the rotor of transmitter 25.

More commonly a servo motor suitably c0ntrolled by a, relay mechanism will be needed to drive the mount 3, and such an arrangement is shown in Figs. 2 and 3.

Turning first to Fig. 2, an electric motor 33 is employed as the servo motor, the operating circuit of which is controlled by contact member 34 the position of which is differentially under control of shaft Ill and the movement produced 33. GEOMElRlCAL lNSiHUlVltN ii.

by motor 33. It will be understood that the electric motor is selected only for the purpose of illustration and that electrically controlled clutches or another type of motor, such as a hydraulic motor may be employed, in which case the contact member would be of a form to control the flow of hydraulic fluid or to operate a swashplate or other suitable form. Therefore the term contact member as used herein is not intended to be limiting but to include any member in direct control of the speed and direction of the motor.

As shown the member 34 is a pivoted electric contact that cooperates with two fixed contacts 35 which are reversely connected to the field of the motor, the common lead of the motor being connected to the contact 34 through a current source. The motor armature is connected through reducing gears to shaft 22 which carries gear 23 that drives the training pinion l8 as in the construction previously described. Shaft 22 is geared to shaft 2| that is geared to shaft 2'4, which latter shaft corresponds to shaft 24 in the construction of Fig. 1 and is differentially connected with the output of the sight deflection angle multiplier to drive the transmitter 25.

We now turn to the means for determining the position of the contact member 34. Centralizing springs bias the member to central or open circuit position and pneumatic means under the differential control of shafts l and 24' actuate the member selectively to one or the other contact position. The shafts l0 and 24' therefore may be considered as the primary movable member and the driven member respectively of a follow-up system.

As shown a piston 36 slidable in a cylinder 31 is pivotally connected to the free end of the pivoted contact member 34 and is normally centralized therein by springs 38. Air under pressure is admitted by pipe 39 to a chamber 40 adjacent to cylinder 31 that communicates through vents with the interior of the cylinder on opposite sides of the piston 36. The size of the vents is controlled by adjustable needle valves so that the flow can be regulated. A pipe 4| leads from the interior of the cylinder on each side of the piston to a valve block 42 in which is a piston valve 43 arranged in control of the valve ports of the two pipes 4|. When the piston valve 43 is in central position as shown, the two ports of pipes 4| are equally uncovered and the flow in the two pipes is equal and hence the pressure on the two sides of piston 36 is equal. As the valve 43 moves up or down it more or less covers one of the ports and builds up a pressure on that side of the piston 36 and rocks the contact member 34 accordingly.

As above stated, this pneumatic means is under the differential control of shafts l0 and 24'. A differential 44 has one input connected to shaft I0 and its other input to shaft 45 geared to shaft 24, and its output is connected to a crank 46 pivoted to the connecting rod of piston 43.

Therefore a displacement of shaft I0 moves piston 43 in one direction or the other and so effects an unbalance of the air pressure on piston 36 and closes the contact in one direction of motor 33. The motor turns accordingly and trains the mount and the sight, at the same time tuning shaft 24 and shaft 45 and hence the center of differential 44 until the valve 43 is restored to central position and the motor stops.

The mechanism also includes a pneumatic impulse device operated by the controller to give a bias to the contact member 34 and close a contact and hence start or accelerate the motor 33 earlier than the action of the generating mechanism becomes effective on the contact member. This is to compensate for the time lag and may be termed a front lash mechanism by analogy to the back lash that normally occurs in any mechanism. This impulse device consists of two closed cylinders having each a fixed partition and a rotatable vane in it dividing the cylinders into two chambers and the corresponding sides of the two cylinders are connected. One vane is connected to be moved by the hand controller and the other is connected to give a bias to the contact member.

As shown, a cylinder 41 has its vane geared to rack 6 and a cylinder 48 has its vane attached to the pivot arbor of member 34. The two sides are connected by pipes 49. The construction will be better understood by reference to Fig. 5. It is apparent that instead of two pipes 49, there may be one pipe and the other side of each cylinder be open to atmosphere which would then be considered the second connecting means.

It will be clear that as the rack 6 is moved the vane of cylinder 41 will turn and create either an increase or decrease of pressure on one side, depending upon the direction of movement of the vane, and a reverse condition on the other side if a second pipe is used. The vane of cylinder 48 is biased accordingly and the contact member 34 is thus caused to close its contact in anticipation of the time that it would be closed by the operation of valve 43.

Means are provided to prevent a too rapid acceleration of motor 33. A viscous drag device 50 has one element fastened on the arbor of the contact member 34 and the other geared to one side of differential 5|. The other side of the differential is loaded with an inertia member .52, while the center of the differential is geared to shaft 2|. The connection is such that as motor 33 is increasing its speed and the inertia member 52 is lagging behind, the drag member 50 is rotated in a direction to open the contact and so restrain the rate of acceleration. When the inertia member catches up so that the speed of its side of the differential corresponds to that of the center, then movement of the viscous drag side of the differential stops and there is no tendency of the contact to open so long as the speed of the motor does not change. When the motor speed slows down, the inertia member keeps on going and produces a movement of the drag output in a direction to'close the contact. In this way the motor is prevented from slowing down too fast.

The embodiment shown in Fig. 3 is the same as that of Fig. 2 except that a compass or equivalent gyroscopic means are provided to take care of a change of ships course. In this case the gyroscope controls the pneumatic valve and in conjunction with its base it constitutes the differential to compare the generated and response movements.

A gyroscope 53 is mounted in the usual gimbal mounting on a base 54, pivoted on the mount 3, so as to have three degrees of freedom and maintain its spin axis on a selected meridian. It therefore functions as an azimuth gyro. Its frame 55 is pivoted on the base 54, preferably though not necessarily coaxially therewith. The valve block 42 is mounted on the base 54 and the connecting rod of the piston valve 43 is pivotally attached to a crank extension on the frame 55. block 42 by way of a special connection in the upper gyro pivot so as to allow relative angular movement. This is shown in detail in Fig. 4. The pipes 4! come in to a relatively stationary cap, the interior of which communicates with passages in the hub portion of the gyro support that connect with pipes 51 leading to the valve block.

In this case the shaft has a worm on its end which meshes with a rack on the circular base 54, and turning of the shaft therefore rotates the base.

The operation will be understood from a reference to the diagram of Fig. 6. The ship on which the apparatus is mounted is assumed to be going in the direction OS. The gyro spin axis is pointing in the direction OM. It is assumed that the sight is pointed at a target in the direction OT. The ships course relative to the datum meridian is Co and the relative bearing of the line of sight is Be and the bearing relative to the datum meridian is B.

The apparatus under ideal condition operates at a rate which just keeps the sight on a target. Thus ball carriage 1b is at the center of disc la, the roller lo is stationary, and the ball carriage 8b is off center just the right amount. But let it be assumed that the mount is training the sight to the right and that the rate is too slow and the sight lags behind the target until an error accumulates. Then it will be necessary to increase the training rate and immediately to advance the sight an amount to remove the accumulated error.

The operator will move his handle to the left so as to move the rack 6 to the right. The direction of the consequent movement of the parts is indicated by arrows. The rate member 11), being moved off center to the right, will cause a movement of the roller 10 at a rate proportional to the displacement of the rate member and an amount depending upon the duration of the displacement. This moves the rate member 8b to the right and so steps up the rate of the roller 80. A quantity proportional to the amount of movement of the roller 10 is added to the output of roller 80 at the differential I5. Also the differential I6 adds an instantaneous amount proportional to the movement of rack 6.

The effect of this relative angular movement of the shaft I0 is to turn the base 54 to the left or counter-clockwise relative to the mount 3. This causes movement of the valve 43 to the left relative to the valve block 42 and actuates the contact member 34 to engage the lower contact 35. This causes the motor 33 to run in a direction to turn the pinion l8 so as to make the mount 3 move to the right or clockwise. The mount carries the base 54 back relative to the gyro until the valve 43 regains its central position. Thereupon the motor stops.

Also the movement of the rack 6 through the pneumatic impulse devices 41 and 48 had closed the contacts 34, 35 earlierthan the base 54 was moved to do it and in this way the corrective action of the motor was promptly started. The motor in accelerating turns the drag device 50 in the direction indicated by the arrow in Fig. 3, and this tends to open the contact 34 and hence prevents too rapid an acceleration of the motor. When the inertia element 52 gets up to speed corresponding with the input of the motor into differential the drag member is stopped, but as the motor slows down the inertia member keeps on going and tends to close the contact 34 The pipes 4| in this case lead to the valve so as to keep the motor energized and thus prevent it from slowing down too rapidly.

Let it be assumed that the ship changes its course relative to the meridian OM but that the bearing angle B is unchanged. The relative bearing angle Bs has to be changed to compensate for the change in the angle Co. This is done automatically by the gyro. The turning of the ship turns mount 3 and hence base 54 relative to the gyro. The valve 43 is thus displaced, the balance of piston 36 is upset, member 34 is actuated and motor 33 caused to operate to bring the base to a position where valve 43 is again in the center. This keep the sight on the target and changes angle Bs so as to keep angle B constant.

Now let it be assumed that angle B changes. The operator does the same thing as he would if the sight was lagging or getting ahead of the target. He moves the controller 5 in the proper direction to step up the shaft I0 and thus move the base 54 relative to the mount 3 with the result above described, the base being moved in the reverse direction to which the motor will move the mount.

Inasmuch as the movement of the controller 5 introduces acceleration by changing a rate that is integrated for a period of time in order to move the final rate member 8b, the resulting movement of the sight is smooth.

It will be appreciated that while for clarity of illustration the fixed contacts 35 are shown substantially spaced, in reality there is little clearance for the contact 34 and the movement of the pivot arbor is not substantial. Therefore when the vane of impulse device 48 is directly connected to the arbor of the contact member 34, as is the case in the construction of Figs. 2 and 3, the vane is limited to the restricted moveent of the arbor when controller 5 is moved. The movement of the vane of impulse device 41 is proportional to the movement of the controller 5, and modifies the relative values of the pressures acting on the two sides of the vane of impulse device 48 to bias the contact member 34 one way or the other. With this construction there is a direct relation between the effective pressure acting on the impulse device 48 and the bias applied to the contact member 34, and the rate of leakage is proportional to a function of the pressure.

In Fig. 7 is shown a construction in which a variable relation between the bias applied to the contact member and the leakage which causes the removal of the bias is obtained. For this purpose a crank and spring connection between the device 48 and the contact member 34 as shown may be used. With this construction a crank arm 58 is secured to the pivot arbor of the contact member 34 and a crank arm 59 is secured to the shaft of the vane of the impulse device 48. The impulse device 48 is mounted so that its shaft is out of line with the pivot arbor of contact member 34, as shown in Figs. 7, 8 and 9. The outer ends of the crank arms 58 and 59 are connected by a spring 68.

With this construction movement of the controller 5 moves the vane of impulse device 41 as already explained, but instead of building up or modifying the pressure acting on the vane of impulse device 48 to bias the contact member directly, the pressure now moves the vane of the impulse device 48 and the arm 59 attached thereto, as illustrated in Fig. 9. The spring as thus displaced imposes a force on the crank 58,

33. GEOMETRIUAL lNSl HUM seems mom thereby placing a bias on the contact member 34. It will be seen that when the center of the cranks 58 and 59 are out of line as in Figs. 7, 8 and 9, the torque reaction from the spring 60 is less on arm 59 than on arm 58. of these torques may be varied by changing the amount the centers are offset and it will be seen that the torque on arm 59 approaches zero as the displacement between the centers approaches the length of the effective radius of arm 58.

The operation with this construction is apparent. When the controller is moved the vane of impulse device 41 is rotated and the vane and crank arm 59 of impulse device 48 are rotated a substantially equal amount. The spring 60 applies a bias to the contact member 34 through the crank arm 58 and modifies the energization of the motor 33. At the same time the action of spring 60 on the vane of device 48 is to return the arm 59 to be in angular agreement with the arm 58, as shown in Fig. 8, and thus eliminate the bias.

With this construction a much smaller difierence in pressure on the two sides of the vanes of the impulse devices is necessary to app y a given bias to the contact member. Because of the smaller difference in pressure, the rate of leakage to permit the return to normal condition can be accurately controlled, the desideratum being that the bias produced by the spring 60 shall hold the contacts 34, 35 closed until the new speed of the motor is attained, whereupon the arm 59 should be in central position and the main control should have become effective to maintain that speed.

It will be apparent that the constructions described may be variously changed without departing from the principles involved. For example, the form of a variable speed device is immaterial so long as the displacement of the controller 5 determines the speed of output of the first device which in turn controls the speed 0-1 output of the second device.

I claim:

1. In gunnery, sight controlling mechanism comprising a rotatable mount, a sight on the mount, training means for the mount, a manual controller, two variable speed drives each including a rate control member and an output member, means operatively connecting the manual controller to the rate control member of one variable speed drive, means operatively connecting the output member of the said one variable speed drive to the rate control member of the other variable speed drive, means operatively connecting the output member of the said other variable speed drive to the said training means, multiplying mechanism having two input elements and one output element, means operatively connecting the rate control member of the said other variable speed drive to one input element of the multiplying mechanism, means for setting the other input element of the multiplying mechanism according to a function of range, whereby the output of the multiplying mechanism represents the sight deflection angle, and means for combining the movement of the output element of the multiplying mechanism with the movement of the training means to position a member in accordance with the gun train order.

2. In gunnery, sight controlling mechanism comprising a rotatable mount, a sight on the mount, training means for the mount, a manual The relation controller, two variable speed drives each including a rate control member and an output member, means operatively connecting the manual controller to the rate control member of one variable speed drive, means operatively connecting the output member of the said one variable speed drive to the rate control member of the other variable speed drive, a differential mechanism having two input elements and an output element, means operatively connecting the output member of the said other variable speed drive to one of the input elements of the differential mechanism, means operatively connecting the output member of the said one variable speed drive to the other input element of the differential mechanism, means differentially connecting the manual controller and the output element of the differential mechanism in operative relation to the said training means, multiplying mechanism having two input elements and one output element, means operatively connecting the rate control member of the said other variable speed drive to one input element of the multiplying mechanism, means for setting the other input element of the multiplying mechanism according to a function of range, whereby the output of the multiplying mechanism represents the sight deflection angle and means for combining the movement of the output element of the multiplying mechanism with the movement of the training means to position a member in accordance with the gun train order.

3. In gunnery, sight controlling mechanism comprising a rotatable mount, a sight on the mount, training means for the mount, a manual controller, two variable speed drives each including a rate control member and an output member, means operatively connecting the manual controller to the rate control member of one variable speed drive, means operatively connecting the output member of'the said one variable speed drive to the rate control member of the other variable speed drive, a servo motor connected to operate the training means, a controller for the servo motor, means difierentially connecting the training means, the manual controller and the output member of the said other variable speed drive to actuate the controller of the servo motor, and impulse transmitting means connected to be actuated by the manual 'con-, troller and operative upon the controller of the servo motor to give an initial impulse to the controller for the servo motor upon movement of the manual controller.

4. In gunnery, sight controlling mechanism comprising a rotatable mount, a sight on the mount, training means for the mount, a manual controller, two variable speed drives each including a rate control member and an output member, means operatively connecting the manual controller to the rate control member of one variable speed drive, means operatively connecting the output member of the said one variable speed drive to the rate control member of the other variable speed drive, a reversible servo motor connected to operate the training means, a source of power for the motor, a contact member in control of the power connection, a base pivotally carried on the mount, a directional gyroscope having a frame pivotally mounted on the base and having a freedom of movement to maintain its spin axis fixed in space, means operatively connecting the output member of the said other variable speed drive to the said base, and means actuated by the relative movement of the gyroscope frame and the base to operate the contact member.

5. In gunnery, sight controlling mechanism comprising a rotatable mount, a sight on the mount, training means for the mount, a manual controller, two variable speed drives each including a rate control member and an output member, means operatively connecting the manual controller to the rate control member of one variable speed drive means operatively connecting the output member of the said one variable speed drive to the rate control member of the other variable speed drive, a reversible servo motor connected to operate the training means, a source of power for the motor, a contact member in control of the power connection, a base pivotally carried on the mount, a directionalgyroscop ga ieunanerniraia l mfi ea,ie. as and having a freedomof movementto maintain its spin axis fixed in space, a differential mechanism having two inputelements and an output element, means operatively connecting the output member of the said other variable speed drive to one of the input elements of the differential mechanism, means operatively connecting the output member of the said one variable speed drive to the other input element of the differential mechanism, means differentially connecting the manual controller and the output element of the differential mechanism in operative relation to the base, and means actuated by the relative movement of the gyroscope frame and the base to operate the contact member.

6. In a follow-up system including a primary movable member a, servo motor and a driven member operated by the motor. a variable speed device for drivin the primary movable member, a manual controller for regulating the speed of the variable speed device, a pneumatic control for the servo motor comprising a movable contact member controlling the application of power to the motor, a pneumatically movable member operatively attached to the contact member and normal y constrained in central position, a source of pneumatic pressure, branch passages of substantially equal capacity leading the pneumatic pressure to the opposite sides of the pneumatically movable member, valve means for differentially venting the branch passages, differential means actuated by relative movement of the primary movable member and the driven mem-- ber to position the valve means, and impulse means between the manual controller and the contact member operative to give an initial impulse to the contact member upon movement of the manual controller.

7. In a follow-up system including a primary movable member, a servo motor and a driven member operated by the motor, a variable speed device for driving the primary movable member, a manual controller for regulating the speed of the variable speed device, a pneumatic control for the servo motor comprising a movable contact member controlling the application of power to the motor, a pneumatically movable member operatively attached to the contact member and normally constrained in central position, a source of pneumatic pressure, branch passages of substantially equal capacity leading the pneumatic pressure to the opposite sides of the pneumatically movable member, valve means for differentially venting the branch passages, differential means actuated by relative movement of the primary movable member and the driven member to position the valve means, two closed chamber members each having a rotative vane pivoted therein and forming a partition, and conduits connecting the corresponding internal sides of the two chamber members, one vane being operatively connected to the manual controller and the other vane being operatively connected to the contact member.

8. In gunnery, sight controlling mechanism comprising a rotatable mount, a sight on the mount, training means for the mount, a manual controller, two variable speed drives each including a rate control member and an output member, means operatively connecting the manual controller to the rate control member of one variable speed drive, means operatively connecting the output member of the said one variable speed drive to the rate control member of the other variable speed drive, a servo motor connected to operate the training means, a pneumatic control for the servo motor comprising a movable contact member controlling the application of power to the motor, a pneumatically movable member operatively attached to the contact member and normally constrained in central position, a source of pneumatic pressure, branch passages of substantially equal capacity leading the pneumatic pressure to the opposite sides of the pneumatically movable member, valve means for differentially venting the branch passages, and means for differentially connecting the manual controller and the output member of said other variable speed drive to actuate the valve means.

9. In gunnery, sight controlling mechanism comprising a rotatable mount, a sight on the mount, training means for the mount, a manual controller, two variable speed drives each including a rate control member and an output member, means operatively connecting the manual controller to the rate control member of one variable speed drive, means operatively connecting the output member of the said one variable speed drive to the rate control member of the other variable speed drive, a servo motor connected to operate the training means, a pneumatic control for the servo motor comprising a movable contact member controlling the application of power to the motor, a pneumatically movable member operatively attached to the contact member and normally constrained in central position, a source of pneumatic pressure, branch passages of substantially equal capacity leading the pneumatic pressure to the opposite sides of the pneumatically movable member, valve means for differentially venting the branch passages, means for differentially connecting the manual controller and the output member of the said other variable speed drive to actuate the valve means, two closed chamber members each having a rotative vane pivoted therein and forming a partition, and conduits connecting the corresponding internal sides of the two chamber members, one vane being operatively connected to the manual controller and the other vane being operatively connected to the contact member.

10. In a follow-up system including a primary movable member, a servo motor and a driven member operated by the servo motor, a variable speed device having an output member for driving the primary movable member, a manual controller for regulating the speed of the variable speed device, a controller for the servo motor, means differentially connecting the manual controller and the output member of the variable speed device to actuate the controller for the so. tEOMETRICAL msmum Search Room 13 servo motor, and impulse transmitting means connected to be actuated by the manual controller and operative upon the controller of the servo motor to give an initial impulse to the controller for the servo motor upon movement of the manual controller.

11. In a follow-up system including a primary movable member, a servo motor and a driven member operated by the servo motor, a variable speed device having an output member for driving the primary movable member, a manual controller for regulating the speed of the variable speed device, a controller for the servo motor, means differentially connecting the manual controller and the output member of the variable speed device to actuate the controller for the servo motor, and yieldable motion transmitting means connected to be actuated by the manual controller and operative upon the controller of the servo motor to apply a bias thereto tending to actuate said servo motor controller upon movement of the manual controller.

12. In a follow-up system including a. primary movable member, a servo motor and a driven member operated by the servo motor, a variable speed device having an output member for driving the primary movable member, a manual controller for regulating the speed of the variable speed device, a controller for the servo motor, means differentially connecting the manual controller and the output member of the variable speed device to actuate the controller for the servo motor, the controller for the servo motor including a pivoted contact member, a crank arm connected to the pivotal axis of the said contact member, a second crank arm mounted for rotation about an axis parallel to the axis of the contact member, yieldable means connecting the crank arms, and yieldable transmitting means connected to be actuated by the manual controller and operative to position the second crank arm to apply a bias to the first mentioned crank arm tending to pivot said member to contact closing position.

WILLIAM H. NEWELL.

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