US2410723A - Turret control system - Google Patents

Description

NOV. 5, 1946. M A EDWARDS ET AL 2,410,723

TURRET CONTROL SYSTEM Filed July 3l, 1942 a z2 Martin Aidu/artis 5 Charles F Bgrum,

Patented Nov. 5, 1946 UNITE PATENT -r1cs TURRET CONTROL SYSTEM Application July 31, 1942, 'Serial No. 458,016

11 Claims.

This invention relates to control systems, more particularly to control systems for power driven gun turrets and the like, and it has for an object the provision of a simple, reliable, and improved control system of this character.

More particularly, the invention relates to control systems for gun turrets used on aircraft, and a more speciflc object of the invention is the provision of means for controlling the train and elevation driving means of the turret so that the gun is automatically controlled to clear the contour of any portion of the craft which may constitute an obstacle in the path of rotation of the gun.

Another object of the invention is the provision of means for always stowing the turret in the same position and to remove power from the turret when the turret is not in operation.

In carrying the invention into eiect in one form thereof, means are provided for driving the turret both in train and in elevation. These driving means are'under the control of a suitable vmanually operated master controlling device, which is provided with an auxiliary switching device that is moved to one operating position to effect the energization of the driving means and is biased to move to a second position in response to the release of pressure thereon. Means are provided which respond to the return of this switching device to its biased position for energizing the turret driving means to stow the turret .in a predetermined neutral position in train and in elevation and then to remove power from the control. In another aspect of the invention, a contour limit is provided on the craft, and the turret is provided with a switching device which partakes of the movements of the turret in train and in elevation and engages the contour limit as the gun approaches a part of the fuselage. The control responds to the engagement of the switching device with the contour limit to control the driving means so that the gun clears the fuselage.

For abetter and more complete understanding of the invention, reference should now be had to the following specication and to the accompanying drawing in which Fig. 1 is a simple, diagrammatical illustration of -an embodiment of the in vention, Fig. 2 is a diagrammatical sketch of an application of the invention and Fig. 3 is a mechanical diagrammatical sketch of a detail. This invention is an improvement of the invention of Martin A. Edwards and Kenneth K. Bowman disclosed in application Serial No. 420,792, Turret control system, led November 28, 1941, now

Patent No. 2,356,152, dated August 22, 1944, and assigned to the same assignee as the assignee of the present invention.

Referring now to the drawing, a top gun turret Ill of a military aircraft II is provided with a machine gun I2 which it is desired to move both in train and in elevation. The machine gun I2 is provided with trunnions I3 and I4 which are journaled in trunnion cradles I5 and I6 to provide for elevation of the gun. The trunnion cradles I5 and I6 are flxedly mounted on a rotating ring lI which is arranged to be rotated in train by suitable driving means illustrated as an electric motor I8. The rotating ring Il may b'e geared to the motor I8 in any suitable manner. In the drawing, the ring is illustrated as being provided with gear teeth which mesh with a pinion gear I9 which is driven by motor I8. In actual practice the gun is usually fixedly mounted in the turret, and the turret itself mounted for rotation in elevation, as well as in train.

Current is supplied to the train motor I8 from a special armature reaction excited dynamoelectric machine 20 to the load brushes of which the armature of the motor I8I is connected by means of conductors 2| and 22. This armature reaction excited machine 20 is provided with a pair of load brushes 20d and with an additional pair of brushes 28e on an axis that is displaced 90 electrical degrees from the axis of the load brushes, and these additional brushes are short circuited as indicated in the drawing. The machine 20 is provided with a main control eld winding 20a which is arranged so that its magnetic axis coincides with the axis of the load brushes. The ilux along this axis causes a current to iiow in the short circuit, and this short circuit current causes the armature to produce a fluxalong the short circuit axis which generates the voltage that appears across the load brushes of the machine. The important characteristics of the armature reaction excited dynamoelectric machine 20 are its exceptionally high speed of response, and its exceptionally high amplication factor, i. e., the

ratio between the magnitude of the current fiowing in the control field winding 20a and the current which iiows in the output circuit of the machine.

The dynamoelectric machine 28 is provided with a compensating eld winding 20h on the load axis of the machine which neutralizes the armature reaction of the machine which results from the armature current that ows in the output circuit of the machine. These compensating iield windings neutralize the load armature reaction 100 per cent and provide an additional Vamount of with respect to the compensating eld winding h, and it is connected across the load brushes of the machine through a portion of a resistor 23 and a capacitor 24. l

The dynamoelectric machine 20 is driven by any suitabledriving means such as the direct current electric motor 25 which is supplied from a suitable direct current source such as represented by the two conductors 26 and 21. The negative side 21 of the source may be grounded to the frame as indicated.

A control potentiometer 28 is connected across the direct current source 28, 21 through the contacts 29a of a relay 29, Another potentiometer 30 and additional resistor 3I are connected in series relationship across the output brushes of the armature reaction excited dynamoelectric machine 20.

The control field winding 20a of the dynamoelectric machine 20 is connected between the midpoint 28a of potentiometer 28 and .the movable contact 30a of potentiometer 30, whereas the movable contact 28h of potentiometer 28 is connected .through normally closed contacts 32a 'f a. relay 32 to conductor 22 which is connected to the lower terminal of potentiometer 30. As a result of these connections, a voltage is applied to .fthe main control eld winding 20a of dynamoelectric machine 20 which is equalto .the difference of the control voltage between the midpoint 28a of potentiometer 28 and the movable contact 28h and the voltage across the active portions of the potentiometer 30 and resistor 3l between the slider 30a and conductor 22. As a, result of these connections, the dynamoelectric machine 20 is caused to generate a voltage which is proportional to the difference of the control voltage produced by the potentiometer 28 and lthe voltage across predetermined portions of potentiometers 30 and 3l between -the slider 30a and the conductor 22 and asa further result, the motor I8 is caused to rotate at a speed proportional .to this difference voltage. As previously pointed out, only a very small current is required to excite the con- Itrol eld winding 20a, and accordingly, the voltage drop across the predetermined portions of the potentiometers 30 and 3| are closely regulated to the control voltage of potentiometer 28. Likewise, the speed of the motor I8 is caused to correspon-d closely to the control voltage of potentiometer 28.

For the purpose of elevating .the gun I2, a second electric motor 33 is provided and this motor is geared .to the trunnion I3 through sector and pinion gears 34 and 35. 'I'he motor 33 is supplied and controlled by means of apparatus 33 which is in all respects identical with .the appa- 4 purpose of simplifying the drawing. The potentiometer 38 corresponds in function with the potentiometer 28 and produces a reference control voltage with respect to which the speed of the elevation drive motor 33 is regulated.

For the purpose of initiating and .controlling the train and elevation movements oi? the turret. a manually operated master controller 39 is provided. This master controller 39 may be mounted in any convenient location within the turret. It is illustrated as being mounted on the train ring gear I1.

As shown, the master controller 39 is provided with a pistolgrip 40 which is pivotally mounted on a shaft 4I. A sleeve 42 having a worm thread is slidably mounted on the shaft 4I and is connected by means of an L-shaped yoke to the arm -40 is moved in a vertical direction, the slider of the train elevation control potentiometer 38 will be moved from its central position and similarly, if .the pistol grip 40 is moved in a horizontal plane, the slider of the train control potentiometer 28 will be moved.

A "dead mans switch 43 is mounted in a suitable position on .the master controller 39. Preferably, this dead mans switch 43 is mounted on the left-hand side of the controller 39 so that it can be grasped by the left hand while the pistol grip 40 is being grasped by the right hand. 'I'he contacts of the dead mans switch 43 are inratus withinvthe dotted rectangle 31 which supplies and controls the train motor I8 and which has been described in the foregoing. Duplication of this apparatus is therefore omitted for the cluded in the energizing circuit of the control relay 2-9.

In order to prevent .the machine gun I2 from firing in-to the structure of .the airplane, a contact mechanism 44 is provided in the circuit of the ring solenoid 45. This contact mechanism comprises a movable contact member 44a mounted on a lead screw 44h and a cam surface contact member 44e which cooperates with the contact member 44a. The lead screw 4412 is connected by gearing to one of the trunnions of the gun, as shown, or to some other point of the elevation drive, and Athe cam member 44e is connected to .the train drive pinion I9. The contact 44a moves along the lead screw when the gun I2 is elevated, and the Vcam member 44C rotates as the turret is rotated in train. The shape of .the surface of the cam contact 44e is such .that it is not in contact with the contact member 44a whenever the gun I2 is in such a position .that it could be fired into any part of Ithe fuselage. As a result, when the gun is in such -a position, the Circuit of the lring solenoid is interrupted andthe gun cannot be fired.

For the purpose of stowing the gun I2 in a predetermined position in train when manual pressure on the dead mans switch 43 is released, suitable means, illustrated as a directional switching device 46, is provided which cooperates with the control relay 32 to control the excitation of the field winding 20a of dynamoelectric machine 20. The directional switching device 48 is actuated by means of a cam 46a which is driven in response to, or in accordance with, the train movement of the turret through suitable driving connections (not shown). The cam 46a is constructed so that one-half of its perimeter is higher, i. e., farther from the center than the perimeter of the other half. Its initial adjustment is such that the cam follower 46b rests in a depression or slot when the gun I2 is in a predetermined neutral position in train. If the turret is rotated in one direction from the neutral position, the cam follower 4Gb remains motionless and the movable contact 46c of the directional switch remains in contact with the upper stationary contact of the switch. If the turret is moved in the opposite direction from its neutral position, the cam follower rides up on the high portion of the cam and actuates the movable contact member 46c from the upper position in which it is shown to the lower position in which it bridges the lower stationary contact of the switch. The upper and lower stationary contacts 46d and 46e of a directional cam switch 46 cooperate With the contacts of the dead mans switch 43 to control the excitation of dynamoelectric machine 20 so as to cause the turret to be driven in that direction in train which provides the shortest path to the neutral.

The cam switch 46 is also provided with a cam member 46j which is driven by, or in accordance with the movement of the turret in train and which has a. slot into which thecam follower 46g is moved when the turret is in the neutral position in train. When the cam follower is in the slot, the movable contact bridges the upper stationary contacts 46h and when the cam follower is on the high portion of the cam, the movable contact bridges the lower stationary contacts 462. The contacts 46h and 461' cooperate with the elevation return to neutral switch 48 and the upper limit switch 49 to effect operation of the elevation motor 33 in a direction to return the gun to a predetermined neutral position in elevation.

For the purpose of controlling the train and elevation motors 33 and 36 in such a manner as to cause the gun I2 to clear any portion of the contour of the fuselage which may present an obstacle to the movement of the gun, the interfering contour is provided with a contour limit 50, and a contour following switch 5I is provided which cooperates with the contour limit 50 to control the control eld windings of the dynamoelectric machines from which the control and elevation motors are supplied. The contour following switch 5I maybe mounted on the gun itself as indicated in Fig. 1, or it may be mounted on any portion of the mechanism which partakes of the motion of the gun and in such a position that it engages the contour limit as the gun approaches the contour which must be cleared.

The switch 5I is provided with a movable contact 5Ia which normally engages and closes stationary contacts 5Ig. It is also provided with normally closed contacts 5Ib and normally open contacts 5 Ic, 5 Id, 5 le, and 5If. The contacts 5Ib, 5Ic and 5Id are mounted in a supporting member 5Ii of insulating material. The contacts 5Ie and 5If are similarly mounted in a supporting member 5I:i. These contacts are operated by means of an operating lever 5Ilc which is rocked about its pivot in response to longitudinal movements of a plunger 5 I I. 'I'hese longitudinal movements of the plunger 5IZ are in turn produced by rocking movement of the contour follower ret clockwise or counterclockwise.

operation of the system itself will `readilybe understood from the following detaileddescription.

'I'he system is placed in condition for operation lby\closing the contacts of the master switch 52. The energizing circuit for the operating coil of the dead mans relay 29 is completed when the gunner grasps the dead mans switch 43. As shown, the movable contact member 43a of the dead mans switch is biased into engagement with the stationary contact 43h by means of a spring 43c. When the gunner grasps the switch 43, the movable contact member 43a is moved against its bias into engagement with the stationary contact 43d to complete an energizing circuit for the relay 29. This circuit is traced from the positive side 26 of the control source through conductor 53 and contacts of the elevation clutch switch 54 and the train clutch switch 55 and contacts 43a and 43d of the ldead .mans switch, and thence by conductor 56 and the coil of the dead mans relay 29 to ground and the negative side 21 of the control source. In response to energization, the dead mans relay 29 open its normally closed contacts 29h and closes its normally open contacts 29a. Contacts 29a in closing complete the energizing circuit for the operating coil of the master switch relay 51 which picks up in response to energlzation and closes its contacts 51a. Assuming the circuit breakers 58 and 59 to be closed, the drive motor 25 for the special dynamoelectric machine 20 and the corresponding drive motor in the elevation controller 36 are connected to the source to drive the dynamoelectric machine 20 and the corresponding dynamoelectric machine in the elevation controller 36 at a speed which is preferably substantially constant.

The closing of contacts 29a of the dead mans relay completes the connection of the field windings |8a and 33a of the train and elevation drive motors I8 and 33, respectively, to the source. It will also be noted that the closing of contacts 29a connects the train control potentiometer 28 and the elevation control potentiometer 38 across the source. The closing of contacts 51a of the master relay also completes the circuit for the firing solenoid 45 as far as the firing trigger 45a.

The turret is rotated in train by moving the pistol grip 40 to the right or to the left depending upon whether it is desired to rotate the tur- Rotation of the pistol grip 40 in a. clockwise direction in a horizontal plane will rotate the slider 28h of the train control potentiometer 28 in aclockwise dlrection from its neutral position. As a result of the movement of the slider 28h from its neutral position, a control voltage is applied to the control leld winding 20a of a polarity such that the voltage generated by the dynamoelectric machine 20 will cause the train drive motorl I8 to rotate the turret in a clockwise direction. Since the voltage supplied to the armature of the motor l'I8 is also supplied to the potentiometers 3B and 3l, the voltage drop between the slider 30a and the conductor 22 is subtracted from the control voltage of the potentiometer 28, and the control field winding .20a is energized by the difference of these two voltages. A condition of balance is quickly established with the train drive motor I8 operatingat a speed proportional to the control voltage from the potentiometer 28. Movement 7 ofthe turret in a clockwise direction brings the low portion of the perimeter of the cam 46a against the cam follower 4Gb and consequently the movable contact member 46c remains in contact with the stationary contact 46d. Simultaneously the cam disk 46j is rotated from its neutral position and the cam follower 48g is forced out of the neutral slot and up onto the high portion of the cam with the result that the movable contact is caused to open contacts 46h and to close contacts 461.

The movement of the gun I2 in elevation is accomplished by an operation which is identical with the operation in train, with the exception that it is initiated by vertical movement of the pistol grip 40.

As the gun I2 is brought to bear on the target, the operator ceases both the lateral and vertical pressure on the`pistol grip 40, and the sliders oi.' the control potentiometers 28 and 38 are returned to their central or zero voltage positions,

with the result that the control iield winding 20a of dynamoelectric machine 20 which supplies the train motor I8 andthe control field winding of the dynamoelectric machine which supplies the elevation motor 33 are deenergized, and the voltages supplied to the train drive motor and the elevation drive motor are reduced to zero.

It may be desired to move the gun rapidly from its position bearing on one target to another position bearing on a new target. For this purpose, a high speed switch 40a is mounted on the pistol grip 40. Depression of this high speed switch causes it to close its contacts to complete an energizing circuit for the operating coil of the high speed relay 60. This circuit is traced from the positive side 26 of the source through conductor 53, the contacts 54 and 55 of the elevation and train clutch switches, contacts 43a and 43d of the dead mans switch, and thence by conductor 56 and the contacts 40a of the high speed switch through the operating coil of relay 60 to ground and the negative side 21 of the source. A similar circuit is completed for the operating coil of the high speed relay of the elevation controller 36 which is connected in parallel with the operating coilof relay 60 by means of conductor 6l. Alternatively, the high speed relay -68 and the high speed relay of the elevation controller may be combined into a single relay with the contacts of both relays mounted on the single structure. In response to energization, high speed relay 60 closes its contacts 60a and 60h. Contact 60a in closing short circuits the entire potentiometer 3|, and as a result, the dynamoelectric machine 20 must generate a higher voltage in order to bring about the balanced condition between the voltage derived from the potentiometer 30 and the voltage of the train control potentiometer 28. This higher voltage is applied to the train drive motor I8 and as a result, Y

the motor is caused to operate at an increased speed. Preferably, the amount of resistance short circuited by the contacts 60a is such that the speed of the motor I8 is tripled.

The high speed operation of the elevation drive is identical with the high speed operation of the train drive.

1f the dead mans switch 43 is released at a time when the gun I2 is not in its neutral position, the control will function to stow the gun in its neutral position both in train and in elevation.

Release of the dead mans switch 43 forces the movable contact 43a to move out of engagement with the stationary contact 43d and to move' to its biased position in contact with the stationary contact 43h. Separation of the contacts 43a and 43d interrupts the energizing circuit for the operating coil o1' thel dead mans relay 29 which drops out to Aopen its normally open contacts 29a and close its normally closed contacts 23h. Contacts 29a in opening remove power from the train control potentiometer 28. Contacts 29h in closing short circuit the portion of the control potentiometer 28 between the neutral point 28a and the slider 28h. As a result, the control iield 20a of the dynamoelectric machine 2l is rapidly deenergized and the voltage supplied to the train drive motor I8 is rapidly reduced to zero. The closing of contacts 43a and 43h of the dead mans switch completes an energizing circuit for the operating coil of the train return to neutral relay 32 which is traced from the positive side 28 of the source through conductor 53 and contacts 54 and 55 of the elevation and train clutch switches, respectively, through contacts 43a and 43h, contacts 46i of the cam switch bridged by the movable contact member and conductor 82 through operating coil of relay 32 to ground and the negative side 21 of the source. Responsively to energization, relay 32 picks up and opens its normally closed contacts 32a and closes its normally open contacts 32h and 32o. Since contacts 32h are connected in parallel with contacts 29a, the master relay 51 remains picked up.

When the turret was rotating in train in a clockwise direction during normal operation, the slider 28h of potentiometer 28 was on the positive half o1 the potentiometer with the result that the polarity oi the lower terminal of the field winding 20a was positive and the polarity of the upper terminal was negative. The opening of contacts 32a interrupts the connection between the potentiometer 28 and the control field winding, and the closing of contacts 32h and 32e connects the control field winding 20a to the source 26, 21 for the reverse polarity. The circuit is traced from the positive side of the source 26 through conductor 53, contacts 32h oi' relay 32, conductor 54, right half of potentiometer 28, conductor 65, iield winding 20a, potentiometer 30 to conductor 22, contacts 32e of relay 32, contacts 46d of the directional cam switch to groundv and the negative side 21 of the source. As a result, the dynamoelectric machine 20 is caused to gencrate a, voltage of reverse polarity, and the train motor I8 drives the turret in a counterclockwise direction.

When the turret arrives at the neutral position in train, the cam disks 46a and 46j are returned to the positions in which they are illustrated. In the neutral position, the cam follower 48g is forced upward into the slot in the cam 46j, .thereby moving the movable contact member out of engagement with the stationary contacts 451' and into engagement with the stationary contacts 45h. The opening of contacts 461' interrupts the energizing circuit for the operating coil of the train return to neutral relay 32, which, responsively to deenergization drops out and closes its normally closed contacts 32a and opens its normally open contacts 32b and 32c. The opening of .contacts 32h and 32c disconnects the control ileld winding 20a of dynamoelectric machine 20 from the source, thereby rapidly to reduce the vol-tage of the dynamoelectric machine 28 to zero and to stop the train drive motor I 8.

The closing of contacts 46h completes an ener- 9 gizing circuit for the operating coil of the elevation" return Yto neutral relay 66. This circuit is ltraced from the positive side 26 of the source through conductor 53 and the contacts 54 and 55 of the clutch switches, contacts 43a and 43h of the dead mans switch, contacts 46h of the cam switch, conductor 61, contacts of the elevation return to neutral switch 48, contacts of the upper limit switch 49, conductor 68, operating coil of relay 66 to ground and the negative side 21 of the source. In response to energization, relay 66 opens its normally closed contacts 66a and closes its normally open contacts'66b and 66e. Since contacts 66C are in parallel with contacts 32h, the master relay 51 remains energized and picked up. Contacts 66a in opening disconnect Ithe potentiometer 38 from the control field winding of the` dynamoelectric machine in the elevation controller 36 which supplies the elevation drive motor 33, and contacts 66h and 66o in closing connect this field winding to the source 26 and 21 for energization of the proper polarity to cause the elevation motor 33 to drive the turret toward the neutral position in elevation. When the gun reaches the neutral position in elevation, the

` sector 34 opens the contacts of the elevation return to neutral switch 48, thereby to interrupt the energizing circuit for the operating coil of the elevation return to neutral relay 66. Responsively to deenergization, relay 66 drops out and closes its normally closed contacts 66a and opens its normally open contacts 66h and 66e to leave the system in a reset condition with the gun` I2 stowed in a predetermined neutral position both in train and in elevation. The opening of contacts 66o interrupts the energizing circuit for the operating coil of master relay 51 which opens its contacts 51a to disconnect the motor 25 and the corresponding motor in the elevation controller from the source.

If, during normal maneuvering, the gun should approach the contour of the fuselage, theswitch 5I will engage the contour limit 50 before the gun strikes the fuselage. When this occurs, it is desirable that the gun shall be moved in a manner to clear the obstruction formed by the contour of the plane. VAssuming that during this operation, the gunner has depressed the high speed switch 40a to eiect high speed operation of the turret both in train and in elevation, the first operation performed in response to the engagement of the switch 5| with the contour limit 50 is to move the movable con-tact member 5Ib out of engagement with its stationary contact, thereby to deenergize the operating coils of the high speed relay 60 and the corresponding high speed relay in the elevation controller 36. Subsequently the contacts 5Ic and 5Ie are closed. Contacts 5Ie in closing'reduce the voltage supplied from the train control potentiometer 28 to the control field winding 20a of the dynamo-electric machine 20 which supplies the train drive motor I8, and the closing of contacts 5Ic performs a similar function with respect to the elevation controller. As a, result, the speeds of both the train drive motor I8 andthe elevation drive motor 33 are rapidly reduced.

Following the reduction in the speed of the motors I8 and 33, the contacts 5If are closed thereby reducing to zero the voltage which is supplied from the control potentiometer 28 to the control eld winding 29a, thereby reducing the voltage of the dynamoelectric machine 2li to zero and stopping the train motor I8. Simultaneously, the movable contact 51a is moved out of engagement with the normally closed stationary contact 5Ig and into engagement with the normally open stationary contact 5 Ih, thereby connecting the field winding of the dynamo- 5 electric machine which supplies the elevation motor 33 to the source 26, 21 for energization in such a direction that the elevation motor 33 elevates the gun I2. Finally, the contacts 5Id are closed, thereby to recomplete the energizing circuit for the operating coil of the high speed relay. As a result, the high speed relay in the elevation controller 36 effects operation of the elevation motor at high speed in the manner described in the foregoing.

As a result of the stopping of the driving of the turret in train and the elevation of the gun I2 at high speed, the gun is caused to clear the contour. As soon as the gun does'clear the contour of the plane, the contacts of the switching device 5I which were previously described as being closed in a predetermined order are restored to their original positions and the normal operation of the turret is resumed. j

An additional feature in the operation is provided by the upper limit switch 49 which serves to limit the travel of the gun to a maximum elevated position. When the gun reaches this maximum position, the movable contact of the limit switch 49 is actuated into engagement with the lower stationary contact 49a to complete an energizing circuit for the operating coil of the elevation return to neutral relay 66. This circuit is traced from the positive side 26 of the source through conductor 53, contacts 54 of the elevation clutch switch, conductor 69, contacts 49a of limit switch 49, conductor 68, operating coil of relay 66 to ground and the negative side 21 of the source. Responsively to energization, relay 66 opens its normally closed contacts 66a and closes its normally open contacts 66h and 66e to cause the elevation motor 33 to depress the gun in the manner described in the foregoing. -Thus, the traved is limited and .the gun is returned automatically to its operating range.

Although in accordance with the provisions of the patent statutes, this invention is described as embodied in concrete form and the principle thereof has been described together with the best mode in which it is now contemplated car- 50 rying out that principle, it will be understood that the apparatus shown and described is merely illustrative and that the invention is not limited thereto, since alterations and modifications will readily suggest themselves to persons skilled 55 in the art without departing from the true spirit of this invention or from the scope of the annexed claims.

What we claim as newA and desire to secure by Letters Patent of the United States is:

1. A gun turret control system comprising an electric motor for driving a member in train, a second electric motor for driving said member in elevation, manually operated controlling means for said motors including a hand grip switch de- 5 vice having an element manually movable to one position to prepare circuits for the energization of said motors and movable to a second position in response to release of manual pressure, and means responsive to movement of said switch- 70 ing device to said second position for energizing said rst motor to drive said member toward a predetermined position in train and for energizing said second motor to drive said member toward a predetermined position in elevation, and

75 limit switch mechanism responsive to movement f l1 of said member for stopping said motors with said member in said predetermined positions in train and elevation.

2. A glm turret control system comprising in combination, a first electric motor i'or driving a member in train, a second electric motor for driving said member in elevation, a master controller for both said motors, said master controller being provided with a switching device having a contact element manually movable to a rst position and biased to move to a second position in response to release of manual pressure, switching means responsive to the direction of rotation of said member in train from a predetermined neutral position for preparing control circuit for said first motor to effect the return of said member to said neutral position, means responsive to the return of said manually movable switch element to said second position for completing said prepared circuits to effect return of said member to said neutral position, and means responsive to return of said member to said neutral position for energizing said second motor to return said member to a predetermined position in elevation. l

3. A gun turret control system comprising in combination, a first electric motor for driving a member in train, a second electric motor for driving said member in elevation, a master controller for both said motors, said master controller being provided with a switching device having a contact element manually movable to a first position and biased to move to a second position in response to release of manual pressure, switching means responsive to the direction of rotation oi' said member in train from a predetemined neutral position for preparing control circuits for said iirst motor to eiect the return of said member to said neutral position, means responsive to the return of said manually movable switch element to said second position for completing said prepared circuits to control said i-lrst motor to drive said member toward said neutral position, limit switch mechanism responsive to arrival of said member at said predetermined neutral position for stopping said iirst notor and energizing said second motor to drive iaid member toward a predetermined neutral position in elevation, and limit switch mechanism responsive to arrival of said member at said pree ietermined position in elevation for stopping said second motor.

4. A gun turret control system comprising a irst motor fordriving a member in train, a e'condA electric motor for driving said member in levation, a switching device having an element nanually movable to a rst position for conrolling the energization of said motors and biysed to move to a, second position in response o release of manual pressure, a directional cam witching deviceresponsive to rotation ofthe aid member in one direction from a predeteriined neutral position for preparing control ciruits to eiect rotation o1' said iirst motor in the averse direction, means responsive to movement E said switch element to said second position ir completing saidprepared control circuits to iuse said first motor to drive said member toard said neutral position, limit switch mechnism for stopping said iirst motor with said iember in said neutral position and energizing tid second motor to depress said member toward predetermined neutral position in elevation, and nit switch mechanism for-stopping said second l2 motor with said m ber in said neutral position in elevation.

5. A gun turret control system comprising an electric motor for rotating a member about a predetermined axis, means for controlling the supply of voltage to said motor comprising a dynamoelectric machine provided with a control tleld winding, a master controller for said dynamoelectric machine comprising `a manually movable element and a control potentiometer operated thereby for producing a control voltage, a second potentiometer connected across the terminals of said motor, electrical connections for applying to said control field winding the diner-- ence between said control voltage and the voltage across a selectable portion of said second potentiometer, a switching device responsive to movement of said member in one direction from a predetermined neutral position for preparing reverse connections to said field winding, a manually operated switching device operable in response to release of manual pressure for completing said reverse connections thereby toy ontrol said motor to drive said member toward said neutral position, and limit switch means for stopping said motor with said member in said neutral position.

6. A gun turret control systemcomprising a first electric motor for driving a member in train, a second electric motor for driving a member in elevation, a rst dynamoelectric machine for controlling the supply of voltage to said rst motor, a second dynamoelectric machine for controlling the supply of voltage to said second motor, each of said dynamoelectric machines being provided with a control field winding, means for supplying variable control voltages to said eld windings thereby tov energize said motors to drive said member, means responsive to movement of said member in one direction from a predetermined neutral position in train for preparing reverse polarity connections from the :tield winding of said first dynamoelectric machine to said control voltage producing means, a switch having an element biased to move to one position in response to release of manual pressure to complete said reverse connections thereby to control said rst motor to drive said member toward said neutral position, limit switch mechanism for stopping said first motor with said member in said neutral position and for completing connections from said iield winding of said second dynamoelectric machine to said control voltage producing means to control said second motor to drive said member toward a predetermined neutral position in elevation, and limit switch mechanism for stopping said second motor with said member in said neutral position in elevation.

7. A gun turret control system'comprising an electric motor for rotating a member about a predetermined axis of rotation, a dynamoelectric machine provided with a control field for controlling the supply of voltage to said motor, means for varying the excitation of said control field winding to vary the speed of said motor, a contour limit for said member, a limit switching device mounted to partake of the movement of said member and to engage said contour limit when said member approaches an obstruction, and responsive to engagement of said limit switching device with said contour limit for controlling the excitation of said field to reduce the speed of said motor, to reverse the direction of rotation of said -motor and t0 increase the speed of said motor in the reverse direction oi rotation 13 thereby to cause said member to clear struction.

8. A gun turret control system comprising a first electric motor for driving a member in train, a second electric motor for driving said member in elevation, a contour limit for said member, a limit switching device mounted to rotate with said member and to engage said contour limit, means responsive to engagement of said limit switch device with said contour limit for stopping both said motors and for energizing said second motor to elevate said member so that said member and limit switch device .clear said contour limit, said limit switch device being operable upon clearing said contour limit to reenergize said motors to continue their original direction of rotation.

9. A gun turret control system comprising an electric motor for rotating a member about a predetermined axis of rotation, means for controlling the supply of voltage to said motor comprising a, dynamoelectric machine provided with a, control field winding, a device for producing a variable control voltage, a potentiometer connected across the armature circuit of said motor, connections for applying to said field Winding a voltage proportional to the difference of said control voltage and the voltage across a predetermined portion of said potentiometer, a speed control switching means for altering said predetermined portion of said potentiometer thereby to eiect operation of said motor at high speed, a contour limit for said member, a limit switching device mounted to partake of the movement of said member and to engage said contour limit when said member approaches an obstruction, and means responsive to engagement of said limit switch with said contour limit for controlling said speed control switching means to reduce the speed of said motor, for reversing the direction of rotation of said motor and for subsequently actuating said speed control switching means to eiect operation of said motor at high speed in the reverse direction.

10. A gun turret control system comprising an electric motor for driving a member in elevation, means for supplying a voltage to said motor comprising an armature reaction excited dynamoelectric machine provided with a eld winding, means for producing a reference control voltage yomprising a manually movable master control member and a potentiometer operated thereby, a resistor connected across the armature circuit of said motor, connections for applying to said iield winding a voltage proportional to the difference of said reference voltage and voltage across a predetermined portion of said resistor thereby to said obcontrol the speed of said motor in accordance with said reference voltage, a speed control switching means for altering said pre-determined portion of said resistor thereby to effect operation of said motor at high speed, a contour limit for said member, a limit switchingI device mounted to partake of the motion of said member and engageable with said limit when said member approaches an obstruction in its path, and means responsive to engagement of said switching device with said contour limit for actuating said high speed switching means to reduce the speed of said motor, for reversing the direction of rotation of said motor and for actuating said high speed switching means to effect operation of said motor in the reverse direction to elevate said member at high speed thereby to clear said obstacle.

l1. A gun turret control system comprising a first drive unit for driving a member in train, a second drive unit for driving said member in elevation, each of said units comprising an electric motor, means for controlling the supply of voltage to said motor comprising a dynamoelectric machine provided with a control eld Winding, a device for producing, a variable reference control voltage, a resistor connected across the armature circuit of said motor, and electrical connections for applying to said control eld winding a voltage proportional to the difference of said reference voltage and a voltage across a. predetermined portion of said resistor, a, master controller having an element manually movable in one plane to actuate one of said reference voltageproducing devices to effect rotation of said member in train and movable in a second plane to actuate the other of said reference voltage producing devices to effect rotation of said member in elevation, a speed controlling switch manually operable to alter said predetermined portions of said resistors to eiect operation of said motors at high speed, a contour limit for said member, a limit switching device mounted to move with said member and to engage said contour limit when said member approaches an obstruction i-n its path, and means responsive to engagement of said limit switching device with said contour limit for actuating said speed controlling switch to reduce the speeds of said motors,- for stopping said train drive motor and reversing the rotation of said elevation motor and for subsequently actuating said speed controlling switch to cause said elevation drive motor to elevate said member at high speed to clear said obstruction.

MARTIN A EDWARDS. CHARLES F. BYRUM.

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