US2405642A - Power gun turret driving mechanism - Google Patents

Description

Aug. 13, 1946. A. CORTE 2,405,642

POWER GUN TURRET DRIVING MECHANISM Filed Dec. 27, 1941 3 SheetsSheet l I /v VLN TOP ALFRED C09 7':

BY Z

Aug. 13, 1946. A. CORTE 2,405,642

POWER GUN TURRET DRIVING MECHANISM Filed Dec. 27, 1941 3 Sheets-Sheet 2 Fla-1H INVENTOR ALFRED COR TE A. CORTE 2,405,

POWER GUN TURRET DRIVING MECHANISM I Filed Dec. 27, 1941 3 Sheets-Sheet 3 IN VENTOR. ALFRED CORTE Patented Aug. 13, 1946 UNITED rsr FFIQE POWER GUN TURRET DRIVING MECHANISM Application December 27, 1941, Serial No. 424,635

Claims.

This invention relates to an improved control for the elevating and traversing movements of power driven turrets, with special reference to light weight turrets such as are required for aircraft, land vehicles, and motor boats when maneuverability, accuracy and delicacy of control are prime considerations.

In the usual type of turret drive such as the controllable speed electric or hydraulic motor, the angular momentum of the drive motor may be as great or greater than that of the turret itself. The eiiect of this on the operation of the turret is that a movement of the control lever is not immediately reflected in a movement of the turret but appears only after a lapse of time necessary for the drive motor to change its speed. If, for instance, a target is picked up whil the turret is moving and the control lever is instantly brought to the stop position, the turret will continue moving until the angular momentum of the turret and the driving train has been absorbed by the friction inherent in the system or introduced for the purpose. Unless the gunner limits himself to movements of the control lever at a tempo commensurate with the decay time of the drive system, and thus in efiect creeps up to his target, he must anticipate the sluggishness of his control by over-controlling. In the situation described above, the gunner would throw his control lever over into the position which would ordinarily cause the turret to turn in the reverse direction, moving the lever back to the stop position as the turret slowed down. Even in the hands of an experienced gunner, this type of control is not satisfactory considering the rapidity and nicety of aim necessary in aircraft engagements.

It is accordingly an object of this invention to minimize the time lag between movement of the turret control lever and the corresponding movement of the turret. A constant speed motor is connected by a simple system of gearing to two clutchesone of which turns in such a direction as to cause the turret to move in a given direction upon engagement, while the other clutch is geared to cause the turret to move in the opposite direction. The pressure plates of the two clutches are connected together to a single control so arranged that movement in one direction from a neutral position engages one clutch while movement in the other direction engages the other. Thus a change of the control lever setting requires only the dissipation of the relatively small angular momentum of the clutch before the corresponding force acts on the turret. The motor will continue rotating at its constant speed. In this way,

the problem of overshoot of the drive system is largely eliminated by driving the turret from a system of clutches rather than directly from the drive motor with its necessarily high angular momentum. Moreover, the torque available to move the turret is that corresponding to th maximum output of the drive motor regardless of the speed of rotation of the turret. This is in direct contrast to the conventional variable speed motor drive Where the torque available to move the turret from a stand-still position is the stalled torque which is always considerably less than the maximum although it is at this point in the operation of the turret that a high, smoothly controlled torque is most needed.

It is also an object of this invention to provide an improved turret drive of the class described wherein overshoot or hunting of the drive or the turret is eliminated by partially preloading rotating clutches adapted to drive the turret in either direction. The coupling between the pressure plates is so arranged that at the stop or neutral position of the control lever, each clutch is partially engaged. However, the two clutches are engaged by an equal amount so that the net force acting on the turret is zero. With this arrangement, the inertia and lost motion of the driving train is taken up, as Well as the reverse torque set up by the overrunning tendency due to the momentum of the turret; but the torque can be smoothly varied from maximum in one direction, through zero to maximum in the other direction.

It is a further object of this invention to provide a turret control of th type described wherein adjustable preloading of oppositely rotating clutches in the driving train enables a constant speed drive to be engaged in any degree desired in either direction without lost motion or overrunning of the turret or drive components, whereby the maximum torque of which the drive is capable can be realized at any speed of rotation of the turret in either direction, including sudden reversals thereof, without a tendency to clutch chatter due to light loading thereof.

It is also an object of this invention to provide a single control for separately or simultaneously operating a turret in traverse and elevation, the control being suchthat it can be used for either direct control from inside the turret or as a remote or robot control for one or more turrets operated from a central aiming station. In either case the operating lever would be moved up, down or sideways just as a gunner would directly operate the breech of a pivotally mounted machine gun in order to follow a moving target,

issued December 12, 1944; it being evident that it is applicable to many other forms, locations,

and types of mobile equipment.

In the drawings: Figure I is a central verticalsectiom'with parts in elevation, through a gun turret embodying the Figure VI is a fragmentary horizontal sectional view taken substantially as indicated by line VI.VI in Figure IV, and

Figure VII is a diagrammaticview of the common drive means for the worms of the elevatable turret segments.

As shown, the particular installation chosen for illustrative purposes is intended to be mounted in the top of a fuselage, for direct control by a gunner centrally located therein. It will be evident that the present invention is directed .to the traversing and elevating controls, either or both of which are equally suitable for the control of nose, tail, side, or bottom turrets for airplanes or other gun mounts.

In the turret shown in the drawings, an approximately parti-spherical housing is composed of spaced side segments It carrying twin machine guns or cannons Ii and mounted for synchronized elevational movements in circular tracks i2 which are supported by a horizontal bearing ring l3 through the medium of supporting aprons Bil. The gunner is located in the central part M of the enclosure, between the segments iii. The tracks i2 have suitable bearings for the segments l and the ring I3 is mounted in a stationary ring 6! through a similar bearing to provide for rotation of the respective turret components about horizontal and vertical axes. The ring l3 has gear teeth with which a driving worm 62 meshes and worms 33 mesh with similar teeth on the peripheries of the segments so that the turret components are separately rotated.- Each worm t2 and S3 is driven by a clutch unit, the casing for each unit being indicated by the numeral E5. The clutch units for driving the segments it and ring l3 are identical, that for the ring l3 being directly connected to its worm 62, while the clutch for the segments l6 drives the separate worms 63 through a common gear train i shown in Figure VII, the clutch for the segments It] being preferably located below the gunners seat pedestal H and having its drive extending axially thereof to the gear train.

The clutch unit it: of the control system was designed to provide a gun directing device which control handles hereinafter referred to to operate, yet would give a very stable, sensitive and instantaneously responsive control of the power drive. The unit consists of a splined shaft l8 for taking the power from a motor :9, a splined shaft 26 for delivering the power to the related worm E2 or 63, anda single control for varying the magnitude and the direction of the torque delivered to the worm.

Mechanically, the unit consists of two multiple disc clutches 2| and 22 with a common driven member or shaft 26. 7 Two driving members 24 and 25 rotate in opposite directions so that engagement of one or other of the clutches will carries two pinions 265 and 21.

turn the driven shaft 26 in either a forward or a reverse direction. Referring to the drawing in Figure III, the pinion shaft 88, is coupled to the drive motor l9 through a spline connection, and The left-hand pinion it drives a gear integral with the driving member 2Q, of one clutch, which may be called the forward clutch. The right-hand pinion 2'! drives the driving member 25 of the reverse clutch through an idler gear 28 rotatablymounted on the end wall of the casing It; by a suitable trunnion (i l; see Figure V. The driven plates of each clutch are coupled to thesplined shaft 20 which in turn is coupled to the related worm 62 or 63.

Control of the two clutches 2i and 22 is effected through a single control rod 29 which is so arranged that movement to one side of a neutral position engages one clutch for a positive drive while movement to the other side engages the other clutch for a positive. The control rod carries two cone-shaped cams 30 and, 3| with their apexes adjustably facing toward each other and arranged to move as a unit laterally with the. rod 29. Each clutch has a set of pressure arms 32 which ride up on the surface of the cone as the cone is moved laterally, and translates such motion into clutch engagement. The two cone-shaped cams 3 3 and 3i ride on ball-bearings,

. and so are free to rotate with the spline shaft to preload the system. At the neutral position of 23, while the longitudinal movement of the control rod 25 is transmitted to the cam assembly through these ball bearings. The two cams can be moved relative to each other by turning a clutch control adjustment screw 3 1 by means of a knob 35 at the end of the control rod. Adjustment of this screw in its 14 pitch thread in a sleeve 36 moves the right cam 31 relative to the rest of the control unit. At the same time, a trunnion 37, through wh'ich the control force is applied, moves on its 28 pitch thread 38, so that the whole control unit is moved back with respect to the trunnion by an amount equal to onehalf the relative movement of the cams. In this way, the neutral position of the trunnion is maintained independently of the setting of the adjustment screw, which can be locked by nuts 39 the trunnion, both clutches are engaged by the same amount so that the turret remains stationary.

In Figures I and II a pair of handles 4] is mounted for sidewise swinging relative to a transverse shaft 42 supported by a forked extension it of the seat pedestal l1. Sidewise bodily move ment'of the handles 4! operatespush and pu l sheathed cables 44 to elevate or depress a sleeve t5 extending down in the column llto operate; would require but a very small pressure on the a fork 46 engaging the trunnion 37 of the traversing clutch, by means of suitable linkage '41. Vertical or angular movement of the handles rotates the shaft 42 to operate push and pull cables 48 to elevate or depress a second sleeve 49 which similarly operates the trunnion of the elevating clutch through linkage 5%).

The operation of the drive of this invention involves the use of a constant speed drive motor with two oppositely rotating clutches which eliminates overshoot of the drive to a large extent. Suppose that a target is picked up and the control handles 4! are instantly brought to the stop or neutral position. The motor, f course, will continue rotating. However, the clutch which has just been disengaged is not free to rotate but is slowed down by the'preload'i'ng of t'he'o'pposite clutch. Although this preloading may be but a small fraction of the total power necessary to turn the turret, it is still of such magnitude that it will bring the clutch to a stop almost instantaneously. The overshoot due to the inertia of the driving unit is then quite effectively damped out. There remains the overshoot due to the inertia of the turret. This inertia tends to turn the clutches. However, since the clutches are partially engaged with the motor, the driving force due to the inertia of the turret is bucked by the preloading torque of the clutch and hence is rapidly damped out.

By the use of preloading, all torques appearing on the drive shaft which are less in magnitude than the preloading on the individual clutches are comprised of the algebraic sum of the two opposing torques of the two clutches. Hence, in no case, does the torque applied to the turret represent the output of a clutch working below its point of stable operation. That this is true may be seen from analysis of the conditions existing at the stop or neutral position of the control lever. At the values of preloading contemplated-ten to thirty percent of the total outputth'e clutches are working well in the region of stable operation. Although the torque on the drive shaft may be zero or of infinitesimal magnitude, it is the resultant of the torques of two clutches operating with a high degree of stability.

One reason for the instability of high power clutches when working at low torques is the looseness in coupling between the clutch and the drive motor. At low torques, the impact upon take up of the slack in the gears or othe elements in the coupling to the motor may be of even greater magnitude than the torque which it is desired to draw. Instability in the form of clutch chatter inevitably results. of the clutches of the present drive automatically preloads the gears which couple the clutches to the motor so that there is never any slack to take Two of these drive units are used, one to con. trol the traverse movement of the turret and one for the elevation. The two clutches are connected to the control handles 4| of which there are twoone right and one 1eft-which are connected together so that the turret can be directed with either of the gunners hands or with both. The connection to the clutch control handles 4! is such that movement of the handles through an arc in the vertical plane controls the elevation clutch while movement of the handles in the horizontal plane controls the traverse clutch. The directing of the guns is perfectly natural to the gunner, being Very similar to the movements he would employ in directing one of the manually aimed machine guns except that no muscular The preloading U their stable driving range, thus eliminating'chateffort on his part is required. Each of the handles is provided with a switch lever 51 which is arranged like a dead-man control in that in grasping the control handles, the switch is thrown on. This switch energizes the constant speed drive motors. Thus, as soon as the gunner assumes the alert position, the drive motors are turned on and the turret will respond to whatever movement is given to the control handles.

It will thus be seen that I have invented an improved power turret drive wherein backlash and overrunning of the turret has been eliminated by adjustable preloading oppositely rotating clutches against each other; and in which the driving clutches are sufficiently loaded as to operate in tering thereof and providin a sensitive and positive control of turret movements from neutral to maximum speed in either direction. It will also be evident that my improved control provides a natural control facilitatin the instinctive operation of the turret while the gunner concentrates his attention on the target.

Having thus described my invention and the present preferred embodiments thereof, I desire to emphasize the fact that many modifications may be resorted to in a manner limited only by a just interpretation of the following claims,

I claim:

1. Mechanism for use with a power driven gun turret having traversing andelevating components and driving mechanism for each of said components comprising a source of power, said mechanism including a pair of oppositely rotating clutches connected to each source of power, means for adjustably preloading said clutches to initially act in opposition to each other, a common driven shaft operatively connected with each pair of clutches to be selectively energized by either of its respective clutches each shaft serving to drive a component, and means for selectively and simultaneously controlling said clutches of either pair of clutches whereby to produce traversing and elevating movements of the turret components in either direction of motion.

2. Mechanism for use with a power driven gun turret capable of traversing and elevating the line of fire and having separate driving mechanism for traversing and elevating the line of fire each comprising a source of power, said mechanism in. cluding a pair of oppositely rotating clutches connected to each source of power, means for adjustably preloading each pair of clutches to initially act in opposition to each other, a common driven shaft operatively connected with each pair of clutches to be selectively energized by either of its respective clutches, each shaft serving to drive a component of the turret, and means for selectively and simultaneously controlling said clutches whereby to produce traversin and elevating movements of the turret in either direction of motion.

3. Mechanism for use with a power driven gun turret so constructed and arranged as to cover both horizontal and vertical fields of fire and having separate driving motors for its movable components, said mechanism comprising a pai of opposed oppositely rotating clutches coupled to each motor for simultaneous rotation thereby, a driven shaft for each of said components and engageable with either or both of said clutches of a related pair of clutches at will, screw thread actuated means for preloading said clutches to initially act in opposition to each other so that both clutches are partially energized in the neutral position'of the driven shaft to prevent backlash in the drive, a control handle movable about a pivot in one plane to control the horizontal clutches and in another plane at right angles thereto to control the vertical clutches, and positive mechanical connections between said handle and said clutches, so constructed and arranged as to energize said clutches in either direction of rotation.

4. Mechanism for operating a movable component comprising a shaft for driving said component, a motor, a pair of oppositely rotating clutches driven by the motor and selectively operable to drive said shaft, means for simultaneously controlling the clutches, and, a single unitary regulable, screw thread actuated means assoclated with the last'named means for preload-

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