US2411270A

US2411270A - Control mechanism

Info

Publication number: US2411270A
Application number: US430132A
Authority: US
Inventors: Fred V Hart; John F D Smith; Jr Lambert S Lindezoth
Original assignee: United Shoe Machinery Corp
Current assignee: United Shoe Machinery Corp
Priority date: 1942-02-09
Filing date: 1942-02-09
Publication date: 1946-11-19
Anticipated expiration: 1963-11-19

Description

Nav. 19, 194s. F. v. HART am 2,411,270

CONTROL MECHANISM Filed Feb. 9. 1942 5 Sheets-Sheet l Nov. 19, 1945. F, v. HART Erm.

CONTROL MECHANISM Filed Feb. 9, 1942 5 Sheets-Shut 2 Nov. 19, 1946. F. v. HART ETL CONTROL MECHANISM Filed Feb. 9, 1942 5 Sheets-Sheet 3 www@ Nov. 19, 1946.

F. v. HART Er AL CONTROL M'ECHANISM Fiied Feb. 9, 1942 5 sheets-sheet 4 Nov. 19, 1946.

F. v. HART ETAL 2,411,270

CONTROL MECHANI SM Filed Feb. 9, 1942 5 Sheets-Sheef 5 R/oHT m LEFT Fgtl. I .232

stented Nov. 19, 1946 CQNTROL MCHANISM tion oil New Jersey applicaties seaman a, ieee, sans?. (ci. sev-iii 9 Claima This invention relates to. control mechanism has for an object the provision of novel and improved means for controlling the power movementV of the gun.

In apparatus for training a machine gun, or other relatively small caliber gun, it is usual to mount the gun for swinging movement about two axes at right angles to each other and to provide hand g'rlps on the back end of the gun by means of 'which it may be moved around until its sights are brought to bear on the target and thereafter held in this position while it is fired, as, for example, is disclosed in United States Letters Patent No. 2,051,034, granted on August 18, 1936,'upon an application led in the'name of Ralph M. Ferguson. Where the gun is heavy, or subjected to theaction of some exterior force, such, for example, as that caused bythe slip stream from the propellers of an airplane, the

. physical eilort required for moving the gun, and

also for holding it trained on the target, is considerable and such as materially to decrease the speed and accuracy of aiming. This is especially the case when the gunner is operating at high altitudes, where even the slightest physical e'ort becomes very tiring. It has, therefore, been proposed to employ power-operated means for moving a gun to train 'it and to provide manual controls, operated by the gunner, for controlling the operation of the power-operated means. However, in prior apparatus of this type, the control of the power-operated mechanism is remote, indirect and/ or discontinuous, so thatV direct manual movement of the gun is not simulated, or

are so constructed that an awkward technique unfamiliar to the gunner must be employed in training the gun. Thus, while the use of prior apparatus of this type relieves the gunner of most of the physical eilort required for moving the gun, it does not give him the same natural feel which hemwould experience in moving the v gun by hand and which is quite essential for highest accuracy and most ready manipulation of the gun. Also, such apparatus usually involves the u'se of complicated, bulky and expensive control mechanisms. t Y

It is, therefore, a more speciiic object of this invention to provide novel and improved mechanism for so controlling the movements lof a power-operated gun that direct manual -movement thereof by means of the usual hand grips is the same technique in training the gun as he lwould ii'he were actually moving the gun manually and by means or" the usual hand grips.' To this end, an important feature of this invention resides inthe provision in power-operated gun-training apparatus of universal control means including a `control handle, located in substantially the same position as and corresponding to one ofthe usual hand grips, the speed. direction and extent of movement of which directly and continuously determine the speed, direction and movement of the gun.

More particularly and when, as in the herein illustrated embodiment of the invention, the power-operated means for moving -the gun are two double-acting fluid-pressure motors arranged to swing a gun about two transverse axes, the novel controlling mechanism may comprise, in accordance with further features of the invenl tion, two reversing valves, each having a shifteble valve member, for directly controlling the'direction and rate of ilow of pressure fluid to vand exhaust from the motors; a control handle common to both valves and carried in substantially the same location on the back end of the gun as a conventional hand grip, the handle being movable at will by the operator along any ofja plu rality of paths corresponding to the paths along which the back end of the gun moves as it is swung about either or both of saidaxes; and op# erating connections directly connecting the control handle and the shiftable valve members so that the shiftable valve members are directly and continuously under the control of the control handle. The reversing valvesA and operating connections, as herein illustrated, are so constructed and arranged that when the control handle is moved by the operator inany direction, at any speed and to any extent, one or both of the duidpressure motors are immediately operated to swing the` gun `about one, or both, of said axes, so that its back end will be moved in the same direction, at the same speed and to the same eX- tent as the handle is moved. That is, the direction in which the handle is moved determines the direction in which one or both of the shiftable valve members are moved with respect to neutral positions in which they are normally retained by yieldable means, so 'that the path along which the back end oi the gun is moved by the fluidpressure motors, and the direction of its movement alongthis path, are directly and continu- 'l ously determined bythe movement of the handie; while the speed of movement of the handle simulated and the operator enabled to employ determines the amount the shiftable members are displaced. at any instant, thus directly and of' the gun. The extent to which the gun is moved is likewise directly and continuously determined by the extent ofmovement yof the handle since, when movement of the handle is stopped, the operating connections return the shiftable valve members to their neutral positions, thus cutting off the flow of pressure iuid to andexhaust from the motors to stop movement of the gun and effectively to block its movement until the handle is again moved by the operator. The power-operated means, e. g., the fluid-motors, are hence directly and continuously under the control of the movable control handle and the operator, simply by moving the handle against the very small resistance of the above-mentioned yieldable means, can cause the gun to be moved by power in exactly the same manner as if he were actually moving it by hand and by stopping movement of the handle can cause the gun to be securely held against movement while it is fired.

Other more speciiic features of the invention reside in the provision; in mechanism for controlling the operation of duid-pressure-operated means for moving a gun, of the type of reversing valves here employed for controlling the flow of pressure fluid to and from fluid-pressure motors; of novel mechanism for operating the reversing valves from a single control handle mounted on the back end of the gun; and of means for steady. ing the movements of the control handle so that the operation oi the motors and movements of the gun are smooth and even.

The above and other objects and features of the invention will appear in the following detailed description of the illustrated embodiment thereof shown in the accompanying drawings, and will be pointed out in the claims.

.ln the drawings,

Fig. 1 is a view in side elevation of an apparatus embodying the features of this invention;

Fig. 2 is a sectional view at an enlarged scale of the apparatus shown in Fig. l taken onthe line I-II of that figure and locking in the direction of the arrows;

Fig. 3 is a sectional view of a portion of the apparatus taken on the line Illlli oi Fig. 2 and looking in the direction of the arrows;

Fig. l is a plan view at an enlarged scale of the right-hand end portion of.' the apparatus shown in Fig. l illustrating the controlling valve n mechanism, the control handle, and the operating connections between the control handle and valve mechanism;

Fig. 5 is a view in end elevation of a portion of the apparatus shown in Fig. 4 with some parts in section;

Fig. 6 is a sectional view of the control valve mechanism taken on line VI-VI of Fig. 4 and looking in the direction of the arrows;

Fig. 7 is another sectional view of the control valve mechanisms taken on line Vil-VII of Fig. 6 and looking in the direction of vthe arrows;

Fig. 8 is a view in side elevation of one of the elements of the control valve mechanism shown .inFig 6;

Fig. 9 is a schematic layout of the operating and controlling mechanisms of the apparatus shown in Figs. 1 to 8; and

Fig. 10 is a view on an enlarged scale of a portion of the control valve mechanism shown in Fig. 6, with some .parts broken away and others in section.

Referring to the drawings, and particularly Figs. l, 2, 3 and 4 thereof, the invention is herein illustrated as embodied in an apparatus for .aai 1,270

training a gun having a breech portion I6 and a. barrel l2. lIwo adaptor bars I4, i4 are mounted one on each side of the gun and each of these r bars extends from the back end of the breech portion forwardly to a joint adjacent to the barrel. These adaptor bars support the gun for swinging movements about a horizontal axis on trunnion pins i6, i8 (Fig. 2) journaled in bearing bushings 26, 22 carried by the upper ends of two supporting

plates

24, 26. A shield of armor pleite 28 is also secured to the forward ends of the adaptor bars by means of

brackets

30, 30. At their lower ends these two supporting

plates

24 and 26 are joined to a hu-b 32 which is journaled for 4swinging movements on a Kingpin 34, the axis of which is at right angles to the axis of pins I6 and i8, that extends through the hub and into a post 36. At its lower end the post is flattened to nt between upstanding portions g8,

4 6 of a carrier block 42 and is held in assembled relation on this block by means of a'crossl-'pin t4 and a spring-pressed plunger 46 in the portion GQ. The upper end of the kingpin is provided with a flange 48 while its lower end has an annular locking groove 56 into which a spring-pressed locking pin 52 projects.

The flange 48 holds the hub 32 down on the upper end of the post 36. When the plunger 46 is withdrawn, the post may be swung forwardly (Fig. l), about. the pin 44, into a horizontal position for stowing the gun away.

The carrier clock 42 is adjustably supported on an arcuate track 54 mounted on a member 56 (Fig. 1) and has a clamping mechanism, including a handle 58,' -by means of which the block may be locked in any desired position on the track. The member 56 may be any flxed struc tural member on which it is desired to mount the gun and, in the illustrated arrangement, is a part of the fuselage adjacent to one end of the gunners cockpit in an airplane. Thus the gun is not only mounted for training movements about two transverse axes at right angles to each other, by moving its back end in one direction or the other along any of a plurality of paths, but the whole mount may be quickly moved along the arcuate track. 5t into any one of a number of different adjusted positions to render the gun more effective in use, particularly when firing at targets on either side of the cockpit.

Movements of the gun in the above manner about the two transverse axes provided by the trunnion pins i6, i8 and the kingpin 34 are efi'ected by power-operated means comprising double-acting fluid-pressure motors 60 and 62 (Figs. l and 2) both of which, as illustrated, are under the control of a single movable control handle 6:3 which preferably, and as shown, is mounted directly on the back end of the gun itself (Figs. l, 4 and 9). Also mounted on the back end of the gun is a fixed handle 66 (Fig. 4) adjacent to which is the iiring. trigger 68 (Fig. 1). These handles are in the same location on the gun as the usual hand grips heretofore provided for use in training the gun manually. As will presently be explained, the control handle 64 is so con-` nected to 4the shiftable valve members of two reversing Valves for directly controlling the operation of the motors 66 and 62 that movements of the control handle by the operator will cause lilre movements to be imparted to the backend of the breech portion Ill of the gun by the mo tors, while holding the control handle against ni ...rent will cause the shiftable valve members to be so positioned that .the gun is held fixed by fluid trapped in the motors. The arrangement is, therefore, such that manual movement of the gun is exactly simulated with substan-I tially no effort required by the operator either in aiming the gun or in holding it xed on a target.

The motor 60, which swings the gun about the trunnion pins I8, I8, comprises a double-ended cylinder which is secured to the adaptor bar |4 on one side of the gun (Figs. 1 and 2) and which has ears '|2, 'l2 journaled on the pin I8. Secured to the upper end of the supporting plate 26 is a block 14, through which the pin I8 extends,

and this :block is shaped to form a quadrant 'I6 that extends down betweenthe ears '|2, '|2 and midway between the opposite ends of the cylinder l0. Mounted in the cylinder is a double-ended piston 'I8 provided with rack teeth 88 which mesh with pinion teeth 82 cut on the quadrant (see Figs. 1, 2 and 9).

Pipes

84 and 86 lead from the opposite ends of thecylinder '|0 to a reversing valve 88 which controls the iiow of pressure fluid to, and its exhaust from, the spaces gr chambers 88 and92 back of each end of the piston 18 (Fig.

' 9). Since the block 14 and quadrant 16 are fixed to the supporting plate 26, when a. shiftable valve Vmember of the reversing valve 88 is moved into position to permit pressure Auid to ow through pipe 84 into the chamber 88 at the left-hand end of cylinder '|8 (Fig. 1) (upper end in Fig. 9), and to permit fluid to be exhausted from the chamber 92 at the opposite end of the cylinder through the pipe 86, the cylinder will move relatively to the piston and will be rocked about the pin |8 in a clockwise direction (Fig. 1), and the back end of the breech portion of the gun, to which this cylinder'is secured through the adaptor bar I8, will move downwardly. Conversely, when the shiftable valve member of the reversing valve 88 is moved into position to permit pressure fluid to flow through pipe 86 into the chamber 92 and fluid to exhaust from the chamber 90 through pipe 84, the gun will be swung reversely in a counterclockwise direction about the axis of pin' I8 and the breech portion of the gun accordingly will be moved upwardly. As will be seen from an inspection of Fig. 9 and the legends thereon, and as will be explained more in detail below, movement of the control handle 64, up or down from a midposition, moves the shiftable member in the direction immediately to start the motor 60 into operation for moving the back end of the breech portion of the gun in the same direction. .When the handle is in the mid-position, as shown in Figs. 1 and 9, the shiftable valve member is held in a neutral position in which ow through the

pipes

84 and 86 isentirely cut off and movement of the about the horizontal axis of pins I6 and I8 is effectively blocked by the iluid trapped at each end of the piston 18.

'Ihe motor 62, which swings the gun about the axis provided by the 'kingpin 34 (Figs. 2 and 3), comprises a double-ended cylinder 94 which is secured to the lower ends of the supporting

plates

24, 26. Mounted within this cylinder is a doubleended piston 86 which is provided with rack teeth 88. 'I'hese rack teeth are in mesh with pin- Aof the breech portion of the gun, which is carried by the supporting plates 243, 26, will be swung to the right, as viewed in Fig. 9. Conversely, when the shiftable valve member of the reversing valve |08 is moved into position to admit pressure uid through hose |86 and to exhaust it through hose RIM, the breech portion of the gun will be moved in the opposite direction or to the left. (As is shown =by the legends on Fig. 9 and as will be exlplained in detail below, movement of the control handle 84 to the right or left, from a midposition, moves the shiftable valve member in the direction immediately to start the motor 62 into operation for moving the back end of the breech portion of the gun to the right or left, respectively. When the handle is in the mid-position, as shown in Fig. 9, the shiftable valve member is held in a neutral position in which it cuts off the tlow of fluid through the hoses |88, |08 and traps fluid at each end of the piston 98, thus blocking movement of the gun about the axis of pin 34. Thus the direction of movement of the back end of the gun by the

motors

68 and 82 is directly and continuously determined by the direction of movement of the control handle 88 by the operator.

The control handle 68 (Figs. 1, 4, 5 and 9) which is common to both reversing valves, is mounted on the back end of the breech portion of the gun for movement relative thereto in opposite directions along any of a plurality of paths in the following manner. This handle is pivoted at its lower end to one arm of a bell-crank lever H8 andat its upper end to a straight lever I6. Each of these levers is fulcrumed for turning movement about a horizontal axis on a block ||8 and these blocks are each pivotally connected to a :bracket |20 for swinging movement about an axis at right angles to said horizontal'axis. These blocks are Joined by a strap |22 from which an arm |28 extends. The bracket |20 is secured at its lower end to one of the adaptor bars I6 and the showing of the handle at-the lower righthand part of the view, and that of the fluid-pressure motor 60, is in side elevation, while the showing of the handle at the lower center, and that of the motor 62, is in plan. The valves 88 and |08 are shown in schematic cross-section and' right-hand end views of these valves, shown associated-with the handle 66, have been swung into the plane of a plan view and, as will be apparent from this g'ure, the handle 68 can be moved, from a mid-position, in opposite directions along any of a plurality of paths. These movements of the handle are transmitted through the links |28 and |38 directlylto the two clamping rings |82 and |36 which, as will now be explained, operate the shlftable valve members of reversing valves 88 and |08.

F.eierring to Figs. 6 and 9, these 'two valves are made in a single block |68 which has two parallel through-and-through bores |62, |66. Liner sleeves |46, |48 within the bores provide operating cylinders respectively for two valve spindles |56, |62. The spindle |60 has four spaced piston portions |50a, lilb, |5|lc and |56d, and the spindle |52 is likewise provided with spaced piston portions |52a, |5217, |52c and |52d, as shown. The upper end of each spindle is of reduced diameter to receive a sleeve |54 which is held in place by means of a thrust washer |55 and a nut |58. Mounted for rotation between the thrust washer and a shoulder on each sleeve |54 is the ilange |60 of a valve-operating nut |62 (see Figs. 4, 6 and 9). The sleeves |46, |48 are held in place against endwise movement within the bores |42, |44 by means of thimbles |64, |66 threaded into the opposite ends of the bores and bearing against opposite ends of the sleeves. The thimbles |66, which are on the top of the block |60, are provided with square threads |68 on which the nuts |62 are mounted. The lead of the threads |66 is. right-handed so that the valve spindles |50 and |52, which are the shiftable valve members, above referred to, will be shifted to the left in Fig. 9, and down in Fig. 6, when their operating nuts are rotated in a clockwise direction as viewed in plan in Fig. 9 and in the opposite direction when the nuts are rotated in a counterclockwise direction. The clamping rings |32 and |84 are secured to these operating nuts by binding screws |3i, |3|, see Fig. 4, so that movements of the control handle 64, transmitted din rectly to these clamping rings through links |26, |86, will result in movements of one or both of the valve spindles, depending on the direction of movement of the handle from its mid-position with respect to the back end of the gun. That is, if the handle is moved up and donn relative to the gun, only the valve spindle |56 of the re-s versing valve 88 will be moved, or if the handle is moved back and f orth from left to right rela-l tive to the gun, only the spindle o the reversing valve |06 will be moved. This is due to the fact that the connection point or" the link |28 to the lever arm H4 is onthe axis line of the blocks H0, ||8 while the link |88 is connected to the arm |24, the position of which is not changed by up-and-down swinging movements of the levers ||4, H6. However, by moving the handle 64 at an angle on either side of the vvertical and either up or down, both valve spindles will be shifted from the neutral positions which they occupy in Figs. 6 and 9 and, as has already been stated, the

motors

60 and 62 each will be started into operation.

which bear on the cylindrical portion |38 of ear |36 of the other clamping ring |36, are slidably mounted in two sets of ears |90, |92 of a bracket |84 that is f secured to the valve block |40 and springs |96, |96 are provided for holding the thrust collars |98, |98 against the inner ears |92, |92 of this bracket. The collars |88, |96 are adjustably secured to the plungers by setscrews 200 (Fig. 4). The adjustable collars |16, |716 and |98, |98 are preferably set so that when the operating handle is released the plungers |10, |12 and |86, |88 just touch the cylindrical portion |33 of their associated clamping ring ears and the operating nuts |62, |62 are adjusted Within their clamping rings in such a manner that the valve spindles |50, |52 will be in neutral position under these conditions.

Pressure fluid is conducted from a suitable source (not shown) to the valve block by means of a ilexible hose 202 which connects into a centrally located transverse duct 204 (Figs. 6 and 9). Pressure fluid is exhausted by means of a ilexible hose 206 which is connected to a vertically extending duct 208 (Fig. '7) that opens into two short transverse ducts 2|0, 2|2. Extending at right angles to these transverse ducts 204, 2|0, 2|2 arethree lateral ducts 2|4, 2|6 and 2|8 (Fig. 6). Each of the sleeves |46, |48 is provided with ve sets of circumferentially arranged

apertures

226, 222, 224, 226 and 228 (Fig. 8), and the block |66 is cored out to form

annular grooves

230, 232, 284, 236 and 238 which are vin alinement with the apertures. In the illustrated construction there are eight apertures in each set and in

sets

222 and 226 four of each eight apertures are of elongated tear-drop shape, while the other four are circular and arranged as shown in Figs. 8 and 10. To avoid confusion in Fig. 6, the reference characters for these apertures and annular grooves are applied, for the most part, only to the sleeve |48 and the right-hand side o1' the block associated with this sleeve but it will be understood that these elements are duplicated in the sleeve |46 and in the left-hand side of the block. Also, in the schematic view of Fig. 9, some of the elements of the valves have been omitted in order further to simplify the disclosure. The pipe 64 communicates with groove 236 and the pipe 86 with groove 232 associated with valve spindle of valve 88, while the hose |04, which is in front of the plan of Fig. 6, communicates with the groove 236 and the hose |06 with the groove 232 associated with the valve spindle |62 o! valve |08. The pressure fluid supply hose 202 communicates with grooves 234 of both valves, through ducts 204 and 2| 6, while the exhaust hose 206 communicates with

grooves

230 and 238 of both valves, through ductsll, 2|2, 2|4 and 2|6.

The operation of each of the two reversing valves is the same and will be described by reference to valve 88 which controls the operation of the motor that swings the gun about a hori- 5 zontal axis. With the valve spindle |50 in its neutral position, the piston portions |5011, |502) just cover the tear-drop shaped apertures of l the

sets

222, 226 in the sleeve |46 (see Figs. 6, 9 and 10) and thus cut off flow through grooves 232, 286 and the

pipes

34, 86. Pressure fluid is, however, being supplied toA the space between the e two piston portions from hose 202, ducts ,rd 2|6, and through groove 234 and apertures 24. Now, assuming that the control handle 64 is moved down, the nut |62 on the spindle |60 `by the piston portion |50a on the side toward aperture 220, since these piston portions have no lap beyond these tear-drop shaped apertures. Pressure fluid will now iiow through the tear-drop apertures 226 into the groove 236 l5 and thence, through hose 84, to the-space 90 at the upper end of piston 'I8 and will be exhausted from the space 92 at the bottom of this piston through pipe 86, -groove 232, tear-drop" shaped apertures 222, apertures 220, groove 230, ducts 2M, 2I0 and 208, to hose 206. As previously explained, this will cause the motor 60 to swing the back end of the gun down and this movement will, of course, continue so long as the valve spindle is held in this opened lposition. Similarly, upward movement of the operating handle will effect upward movement of the back end of the gun. Now the valve spindle moves up (Fig. 6)

or to the right (Figs. 9 and 10), uncovering the large ends of the tear-drop shaped apertures 222 on their sides toward apertures 4224 to admit pressure uid to groove 232 and to pipe 86 and the small ends of the tear-drop apertures 226 on their sides toward apertures 228l thus opening groove 236 and pipe 84 to permit exhaust of fluid 35 through tear-drop shaped` apertures 226, apertures 226, groove 238, ducts 2|8, 2|2 and 208, and hose 206. The action of the other valve spindle |52 to control the operation of the motor 62 is exactly the same as that just described and, as has been already pointed out, movements of the back part of the gun sidewise are in the same direction as the lateral movements of the handle 64.

The speed at which the two motors operate will be determined by the rate of flow of pressure uid thereto and exhaust therefrom and the

apertures

222, 226 are shaped and arranged to provide for regulating this ow. As has been stated, the piston portions I a and |50band also piston 50 portions |52a and |5212, have no lap and are of such width as just to cover the tear-drop? apertures when in neutral position. Accordingly, the instant that either of these spindles |50, |52 is shifted from its neutral position, the tear-drop 55

apertures

222 and 226 of its associated valve are uncovered and the motor controlled thereby is immediately started in operation at a speed dep pending on the amount the apertures are uncovered. Accordingly, if the handle 64 is displaced 80 only a little the iiow of pressure iiuid will be small and the action of the motor, or motors, slow. On the other hand, if the displacement of the handle is greater, the ilow of pressure fluid will be larger and the speed of the motor, or motors, 65 increased. Due, however, to the tear-drop shape of certain of the apertures- 222 and 226 and the arrangement of the

circular apertures

222 and 226 with respect to the tear-drop shaped

apertures

222 and 226,the increase in the 70 amount of uncovering of these apertures for admitting pressure uid -occurs at a. greater rate than does the uncovering for exhausting fluid. This will be understood by reference to Fig. 10 from which it will be seen that, when the spindle 76 50 is moved to the left, the "tear-drop shaped apertures 226, through which pressure uid is admitted, are progressively uncovered at their large ends while the tear-drop shaped apertures 222, through which pressure iuid is exhausted are likewise progressively uncovered but at their small ends. Also, the circular apertures 226 are uncovered before the circular apertures 222. The same action takes place in the opposite sense when the spindle is moved to the. right. The shape and arrangement of the

apertures

226 and 222 thus provide for a metered ow of pressure uid to, and exhaust from, the motors by the progressive uncovering of these apertures, the rate of which is greater for those apertures through which the pressure fluid ows to the motors than for those through which fluid is exhausted. This shape and

arrangementof apertures

222 and 226 insures smoothness of action in the motors by causing a slight back pressure 'in their exhausting ends.

This back pressure is maintained by the action of

apertures

222 and 226 until just before the trailing edge of the piston portions a or b reaches the middle of the

circular apertures

222 or 226, which point is substantially at 'the extreme normal limit oi move- `ment of the valve spindles |50, |52. In this manner there is always a back pressure, due to exhaust throttling. in the two motors so that overtravel or running away of the motors is prevented and a very smooth action is obtained. It will be understood that the number, size and shape of these apertures, as well as the ratio of the number of circular apertures to "teardrop shaped apertures, may be varied to suit the different operating conditions', which may be encountered in this or other types of apparatus, while still obtaining the metered now and back pressure action above described. 'I'he valve pistons are all of the same diameter so thatthe spin#- dles are balanced and grooves 240 are provided .in the end pistons c and d to drain back any leakage uid to exhaust.l Sylphon seals 242, 244 are connected to opposite ends of each spindle, as shown.

By mounting the control handle on the device which is to be moved by the two' motors,`i. e., on the back end ofthe gun, a virtual follow-up action is obtained. Referring to Figs. 1, 2 and 9,

and considering first movements of the gun aboutthe horizontal axis providedby pins I6, I8, let it be assumed that the operator wishes to' elevate the back end of the gun to aim it along the line X-X (Fig. l) To do this he grasps the handle 64 and lifts it up. turning the levers ||4 and ||6 f through the angle a (Fig. 9). This movement of the handle moves the shiftable member of the valve 88, through the connections ||4, |20,

|62, |68, immediately .to start the motor 60 in operation to move the back end of the gun up# wards in the same direction as the movement of the handle, and this movement of the gun will continue until the shiftable member |50 is returned to. its neutral position. Return of the shiftable member |60 is eected by a. follow-up action from the gun, back through the lever H4,

link |28, nut |62 and threads |68 from the handle 64, to the valve spindle |50 when movement of` the handle 64 is stopped. Hence, so long as the operator keeps moving the handle up, the valve spindle |60 will be displaced and the backend ofthe gun will he moved by the motor 60.

When the desired orientation is reached, in this case when the axis of the gun coincides with line XX, the operator holds the handle 'still 1 and |96 are required for operating the handle G4. With such l an arrangement, only a slight pressure of the 'l hand is required to move the handle away from its neutral position and thus start the gun movl1 and movement of the gun, by virtue of the followup action just mentioned, returns the spindle |50 to neutral position, whereupon the gun stops. The same kind of action occurs when the handle is moved down for the purpose of aiming the gun along the line Y-Y. Hence the extent to which the gun is moved is directly and continuously determined by the extent of movement of` the handle 64. Also, the speed at which the gun moves will be determined by the magnitude of the angle e as this governs the displacement of the spindle |50 from neutral position. Since, at any instant during the movement of the gun the magnitude of the angle a will depend on the amount the hand is kept ahead of the gun, it follows that the speed of movement of the operatcr's hand, directly and continuously, determines the speedof movement of the gun. As has already been explained, the direction of movement of the gun is also directly and continuously determined by the direction of movement of the handle 64. Swinging movements of the gun about the vertical axis provided by the kingpin 34, by means of the other motor 62, are controlled through the valve |08 by appropriate movements of' the handle 64 laterally about the pivotal axis of blocks H8, H8 and with the same follow-up action and direct and continuous control of the speed direction and extent of such movement, as will be understood. Combinations of lateral and up-and-down movements of the handle 64, of course,I will produce corresponding oblique swinging movements of the gun about two axes at right angles to each other. In fact, the back end of the gun follows all movements of the handle 64 in substantially the same manner as if the handle 64 were fixed thereto, the gun being continuously and directly under the control of the hand which grasps the handle. However, theforces which move the gun are supplied by the pump which delivers pressure fluid to the hose 202, and the only muscular effort required of the operator is the small amount necessary to overcome the resistance of the relatively light springs |80, |96. In operating the gun, the gunner experiences the same feel as though he vwere actually moving the gun in the usual manner, i. e., by gripping the two handles 64 and S6, and he can readily aim the gun, by means of

sights

248, 248, on a fixed target or cause it to track a moving target with the greatest of ease. Furthermore, being relieved of the muscular -eiort which would otherwise be required quickly to move a heavy gun through a large angle or to move the gun against for example the slip stream of the propeller of the plane, or to hold it aimed against such exterior force, this manipulation of the gun is greatly facilitated. inasmuch as the two operating handles 64 and 66 occupy the same positions on the gun as those usually provided for manual operation, no new technique need by mastered by the gunner.

VAs has been previously stated, the springs |80 relatively light to reduce the effort If the handle is moved quite far, a very rapid movement of the gun will follow, and when the gun catches up with the handle it will be suddenly stopped. There is considerable flexibility in the gun mount 'and this springiness may cause the gun to bounce somewhat and shake the an exterior force, such as fil ' pressure-operated 12 operators hand which is on the handle 64. Such movements of the operators hand are, of course, transmitted back to the reversing valves with the result that the movements of the gun become jerky and it would be difficult to aim with any degree of accuracy or to follow a moving target in a satisfactory manner. To overcome this tendency,

dashpots

250, 252 are connected to the lever H6 and arm |24. These-'serve to steady the movements of the handle 64 and to dampen out any vibrations either of the gun or of the operators hand.

Having described the invention, what we claim as new and desire to secure by Letters Patent lof the United States is:

1. In apparatus for training a gun, the combination with a gun mounted for universal swinging movement about two transverse axes, of uidmechanisms for swinging the gun, a control means for each of said mechanisms, an operating member common to all of said control lmeans comprising a control handle movably mounted on the back end of the gun, in substantially the same location as the usual Ahand grip, to start said mechanisms in operation` and means for operating the control means directly by movements of the handle, said control means and said operating means being so constructed and arranged that the direction, speed and extent of swinging movement of the gun are directly and continuously determined by the direction` speed and extent of movement of the handle.

2. In apparatus for training a gun, the combination with a gun mounted for universal swinging movement about two transverse axes, olla double-acting fluid-pressure motor for swinging the gun about each axis respectively, two reversing valves movable with the gun and adapted selectively to control the direction and rate of ilowof pressure fluid to and from said different motors respectively, verslng valves, and means for actuating said valve-operating means including a control handle mounted on the back end of the gun, in substantially the same location as the usual hand grip, for movement relative thereto at will by an operator to start said motors in operation and connections between the handle and the gun and between the handle and the operating means, said connections and said valves being so constructed and arranged that the direction, speed and extent of the swinging are directly and continuously determined by the direction, speed and extent of movement of they,

control handle.

3. In apparatus for training a gun, the combination with a. gun mounted for universal swinging movement about two transverse axes, of a double-acting duid-pressure motor for swinging the gun about each axis respectively, two reversing valves, each of said reversing valves having a piston for controlling selectively the direction and rate of ow of pressure iiuid to and from one of the motors, means for normally holding each piston in position to cut on ilow to or from a motor, and means for displacing each of said pistons in opposite directions from said position including a control handle mounted on the back end of the gun, in substantially the same location as the usual hand grip, for movement relative thereto at will by an operator to start said motors in operation and connections between the handle and the gun and between the handle and the displacing means, said conoperating means for said removement of the gun i3 nections and said valves being so constructed and arranged that the direction, speed and extent of the swinging movement of the gun are directly and continuously determined by the direction, speed and extent of movement of the control handle.

4. In apparatus for training a gun, the combination witha gun mounted for universal swinging movement' about two transverse axes, of a uid-pressure motor including a double-acting piston for swinging the gun about each axis respectively, a reversing valve associated with each motor for controlling the operation vof that motor, each of said reversing valves comprising a body portion provided with a longitudinal bore and a valve member having spaced piston portions slidable in the bore, a supply conduit leading from a pressure uid source to each of said valves and opening into the bores between said piston portions, connections between the bore of each re-' verslng valve and opposite ends of its associated motor including apertures in the body portion normally just covered by said piston portions, exhaust conduits connected to the bore of each reversing valve, operating means for moving th'e valve members of said reversing valves selectively to connect their supply conduit to one end of the associated motor through the space between the piston portions and simultaneously to connect the opposite end of the motor to one of the exhaust conduits, and a member common to both operating means comprising a control handle mounted on the back end of the gun in substantially the same location as the usual hand grip and movable at will by an operator for operating said reversing valves, said apertures being so shaped and arranged that the valve members progressively uncover them as said members are moved, thereby to provide a metered ilow of pressure iluid to, and exhaust from, the duid-pressure motors.

5. In apparatus for training a gun, the combination with a gun mounted for universal swinging movement about two transverse axes, of a duid-pressure motor including a double-acting piston for swinging the gun about each axis respectively, a reversing valve associated with each motor for controlling the operation of that motor, each of said reversing valves comprising a body portion provided with a longitudinal bore and a, valve member having spaced piston portions slidable in the bore, a supply conduit leading from a pressure fluid source to each of said valves and opening into the bores between said piston portions, connections between the bore of each reversing valve and opposite ends of its associated motor including apertures in the body portion normally 'just covered by said piston portions, exhaust conduits connected to the bore of each reversing valve, operating means for moving the valve members of said reversing valves selectively to connect their supply conduit to one end of the associated motor through the space -between the piston portions and simultaneously to connect the opposite end of the motor to one of the exhaust conduits, and a member common to both operating means comprising acontrol handle mounted on the back end of the gun in substantially the same location as the usual hand grip and movable at will by an operator for operating said reversing valves, said apertures being so arranged and so shaped that the valve members progressively uncover them, as thel members are moved, with the rate of uncovering rate of uncovering of the apertures through 'which pressure .fluid is exhausted from the oppobody portion provided with a longitudinal bore' and a valve member having spaced piston portions slidable in the bore, a supply conduit leading from a pressure fluid source to each of said valves and opening into the bores between said piston portions, connections between the bore oi each reversing valve and opposite ends of its associated motor including apertures in the body portion normally covered by said piston portions, exhaust conduits connected to the bore of each reversing valve, operating means for moving the valve members of said reversing valves selectively to connect their supply conduit to one end of the `associated motor through the space between the piston portions and simultaneously to connect the opposite end of the motor to one of the exhaust conduits, and a member common to both operating means comprising o, control handle mounted on the back end of the gun in substantially the same location as the usual hand grip and movable at will by an operator for operating said reversing valves, said piston portions being of such size as exactly to cover said apertures so that the motors' are operated immediately upon the slightest movement of the valve members in either direction from a neutral position and are blocked against movement by exterior forces acting on the gun when said valve members are returned to said neutral position.

7. In apparatus for training a gun, the combination with a gun mounted for universal swinging movement about two transverse axes, of a double-acting fluid-pressure motor for swinging the gun about each axis respectively, two reversing valves, each of said reversing valves having a casing and a piston for controlling selectively the direction and rate of ow oi pressure uid to and from one of the motors, means for normally holding the pistons in position to cut ofi flow to or from the motors, means for displacing each of said pistons in opposite directions from said position, a control handle mounted on the back end of the gun, in substantially the same location as the usual hand grip, for movement relative thereto by an operator, connections between the'handle and the gun and between the handle and the displacing means .so Aconstructed and arranged that the direction, speed and extent of the swinging movements of the gun by said-motors are directly and continuously determined by the direction, speed and extent of movement of the cont-rol handle by the operator, each of said plston-displacing means comprising a nut threaded to the casing and operatively connected to the corresponding piston and said connections between the handle and piston-displacing means including linkages for eiecting rotation of the nuts and displacement of the pistons by movement of the handle.

`8. In apparatus for training a gun, the combination with a gun mounted for universal swinging movement about two transverse axes, of uidpressure motors for swinging the gun respectively about said axes, valve means for directly controlling the direction and rate of flow of pressure fluid to and from the motors, a control handie mounted on the back end oi the gun, ln substantially the same location as the usual hand grip, and movable relatively thereto at will by an operator for operating said valves selectively to effect swinging movement of 'the gun by the motors, operative connections between'said handle and the valve means so constructed and arranged l that thedirection, speed and extent of swinging movementv of the gun by the duid-pressure motors are directly and continuously determined by the direction, speed and extent of movement of the handle by the operator, and dash pots associated with said handle for steadylng its movey ments relative to the gun.

9. In apparatus for training a gun, the combination with a gun mounted for universal movement about two transverse axes, of a, double-acting fluid-pressure motor for swinging the gun about each axis respectively, two reversing valves, each of said valves having a casing and a piston of iiow of pressure fluid to and from one of the motors, means for normally holding the pistons in position to cut of! ilow to or from the motors, means for displacing each of said pistons in opposite directions from said position, a control handle mounted on the back end of the gun, in substantially the same location as.the usual hand grip, for movement relative thereto by an, operator, connections between the handle and the gun and between the handle and the displacing means so constructed and arranged that the direction, speed and extent of the swinging movements of the gun by said motors are directly and continuously determined by the direction, speed and extent of movement of the control handle by the operator, each of said piston-displacing means comprising a rotatable member and Said connections including linkages for effecting rotation oi.' said members by movement of the handle.

FRED V. HART. JOHN F. D. SMITH. LAll/CBERT S. LINDEROTH, JR.