US2571886A - Control device - Google Patents

Description

P. S. JACKSON Oct. 16,1951

CONTROL DEVICE 4 Sheets-Sheet 1 Paul Filed Oct. 25, 1948 P. S. JACKSON Oct. 16, 1951 CONTROL DEVICE 4 Sheets-Sheet 2 Filed 001:. 23, 1948 Oct. 16, 1951 5. JACKSON 2,571,886

CONTROL DEVICE Filed Oct. 23, 1948 4 Sheets-Sheet 5 IIIIIIIIIII P. S. JACKSON Oct. 16, 1951 CONTROL DEVICE 4 She ets-Sheet 4,

Filed Oct. 23, 1948 INVENTOR.

Patented Oct. 16 1951 U N I TED S TATE S PAT EN'T O F F I -CE CONTROL DEVICE Application October 23, 1948, Serial .No. 56,134

19 Claims.

This invention relates to control mechanisms and more particularly to .a control mechanism for a reciprocating member.

It is a general object of this invention to producea controldevice for a reciprooatingmember.

'It is a more specific object of this invention to produce a device for .controlling .the length of stroke of a reciprocating member.

It is va further .objectof this invention to produce .a device for controlling the stroke of a hydraulically .reciprocated member where unequal volumes of fluid are moved with reciprocation in each direction.

.It is a further objectof this invention to pro- .duce a control device according to any of the precedingparagraphs which isreadily adjustable.

Yet another objectoi the invention is to produce .a control device having a control panel on which are located .adjllstable means for controlling the volume of fluid for reciprocating a member and jhavingindicating means associated with the panel .for visuallyindicating the setting of theadjustable means.

.Another .and further objects of the invention will be apparent-from the following description .and drawings in which:

Fig. .1 is .a diagrammatic view of the control .and the hydraulic circuit;

.Fig. .2 is.a front feleva'tional viewof .the-con- .trol .panel with the .face vremoved;

Fig. .3 is a sectionalong line ,3.3 of Fig.2;

Fig. .4 .is a view like Fig. .2 with .the faceof the panel .in .place;

Eig. 5-is .asectionalview along,line.5,-i.5 of Fig. 4;

,Fig; 6 is a .detailedsectional view of .thevolume control for the pump; .and

; Fig. 7 is an elevational view of ,the .entire. control "panel.

While vmy invention is susceptible of embodi- .-ment many-different;for1ns,-l haveshown the drawings and willherein describein-detail onesuch embodiment, aWith the understanding .that flthe presentdisclosure -is to be considered -as an exemplificationof .the principIe of them- 'vention and isgnot-intendedto limit itheinvention to the embodiment illustrated. iI'he scope of :thezinvention -will:.-be;pointed. out in-.the appended -.c1aims.

-.For1the ,purpose= of exemplary a disclosure J ,h.ave .chosen .to :describe any invention as-used. inconjunction with -,an zexerciser-forexercisingathe -recoil mechanism of a gun, although it will ,be

gapparentifrom:the disolosure thatithe devicermay yhe ,used -.tocontrol--.the gstro k e. of .any-.rec iprocating idevice. r

Referring vnow to Fig. l of the drawings I show a reversible, variable delivery hydraulic pump L0 which may be reversed in the usual manner through energization of solenoids H and 12. The volume of fluid moved in either direction by the pump may be regulated by regulating means I3 and M which last-named means may be controlled by knobs l5 and i6 mounted upon a control panel to be later described, which panel bears an inscribed dial H. The knobs are connected to their respective volume control devices by rotatable rods [8 and I9.

Interposed in the hydraulic circuit is a fourway hold-up valve 2E1 having a casing 2! and a longitudinal bore 22 in the casing. 'Slidablein the bore is a spool valve device 23. The valve casing is provided with three parts, 24, "25 and 2E on one side thereof and a single port 2,! on the other side. The spool valve 23 is slidable longitudinally in the bore and is urged 'ina clos- Ling direction by spring 28. A solenoid device 29 is adapted to operate a valve mechanism 30 to permit pilot pressure to shift the valve 23 longitudinally in .the casing to open position a ainst the tension of the spring 28. The bore is provided with a passage 31 connecting with annular grooves 32 .and 33 and is also provided with annular grooves 34,, '35 and '36. The valve 20 has but two positions, the on position as .shown in Fig. l .and an off position in which .all ports .are blocked.

Also located in the hydraulic circuit is adif- ,terential relief valve 33,0 which pomprises aoasing 4! having a bore '42 therein. A spool valve 43 ,is .slidable longitudinally in the boreand urged -toward movement ,in one direction by a spring .45. The valve Jill is provided with three .ports 45, .45 and .47 on one sideoi the casing, a single iport 4.8 .on the other .side of jtheoasing', and a portifiii enteringdirectly to the borej5'2. A port gen .is. .a1so;provided at one end ,of the bore for purposes to be hereinafter described.

" Withthe .parts in theposition shown inFig. l

hydraulic iluid under pressure from the pump .IB is directed into the cylinder line conduit '5i .and enters .the'boretZthrough thepor @149. The .fluid passes by the .spool valve A3 and into a Passage. 5.2.inthevalveyifl to conduit "53. From .icondnit 153 fluid is directed into .a' hydraulic metering motor .5 4 which 4 motor is rotated by .the action of fluid passing therethrouglrand transmits that rotation by means of shaft -5 -.c.oup ng flann l sp r ducer :5 t a sha -;58 connected ..to a control tilevice 59.. I prefer 55..

to use a :hydraulic metering .motor of the type shown when apparatus ,is. used inthe. manner illustrated wherein portability of the entire device is essential. However, where the control device is to be used with a, reciprocating member which is fixed in position, for example, as on a machine tool, I may use a rack and pinion device or other motor means connected directly to the reciprocating member to rotate the shaft 58.

From the metering motor, cylinder line fluid passes into a conduit 65 and enters the port 25 of valve 20. The fluid passes along the bore 32, into the annular groove 35 and out port 26 to a conduit 6!. The conduit 6i connects with a conduit 62 and thence directly into the cylinder E3 in which the reciprocating member is located to reciprocate the member in one direction. Also connected to the conduit 62 is a bleeder valve 54 and a pressure gauge 55. The conduit 62 also opens to the bore 42 of valve 40 through the port and fluid pressure against the plunger 56' secured to the spool valveserves to urge the spool valve 43 to the position shown.

Removably attached to the other end of the cylinder 63 is a hydraulic jack 64 having a member adapted to bear against the rod 65 connected to the reciprocating member. It is understood that the rod 65 is normally a part of the recoil mechanism of the gun. Fluid returning from the jack E4 enters the jack line 66 in which bleeder valves Bi and pressure gauge 68 are located and passes along the conduit 59 and into the port 24 of the valve 2:). The fluid thence passes along annular groove 34 into the passage 3] and thence into the conduit 10 by means of the port 27. The conduit 10 is connected to a conduit Tl which leads into the port 12 of pump l0 and also is connected to the valve 40.

As the volume of fluid pumped by the pump 10 exceeds the volume returned from the hydraulic jack 54, means are provided for making up the difference between the volumes. Accordingly, I provide a make-up pump I3 driven by the same means as drives the pump [0 and make-up fluid is supplied into the conduit 14 having a pressure gauge 15 connected therewith and thence into the valve mechanism 38 for shifting the spool valve 23 in accordance with the position of the solenoid 29. Make-up fluid is also supplied directly to the conduit 16 which is connected to a conduit i7 and port 4! of valve 40. With the valve in the position shown,

make-up fluid may enter the port 41, pass along the annular groove l! and bore 42 and into the conduit H through the port 45.

When the reciprocating member in the cylinder 53 reaches the end of its stroke my control device hereinafter to be explained serves to reverse the pump Hl. With the pump l0 reversed, fluid under pressure reverses its direction in the line ii and passes through the means just described into the jack line 66. Fluid returning from the cylinder line through conduit 62 reverses its direction through the valve 28 and the metering motor 54 to rotate the motor the same number of revolutions as when the circuits Were reversed, but in the opposite direction. As suction is applied to the line 62 the spool 43 of valve 40 is shifted upward (as shown in Fig. l) to block off ports 46 and 41 and prevent jack line pressure from the pump Hi from entering the make-up circuit. Port 49 is also blocked and port 45 is connected with the passage 52 so that all hydraulic fluid returning from cylinder 63 through valve and motor 54 line 53 is directed through port 45, 52 and bore 42 to port 45 into the conduit 88 connected to 4 the tank or sump. With the valve in this position, pump suction is through a pipe and check valve (not shown), but incorporated in the pump.

My control device contemplates means for energizing the solenoids H and I2 to reverse pump Hi When the reciprocating member in the cylinder 63 reaches the end of its stroke in each direction. Accordingly, the shaft 58 which is rotated by the metering motor is mounted in r a housing 8! and terminates in a reduced portion 82 extending beyond the face of a dial 83. A hollow shaft 84 is frictionally secured to the portion 82 and similarly extends beyond the face of the dial 83 and terminates in a knob-like portion 85. A spring 86 is positioned between a shoulder portion 8! of the knob 85 and a cap 88 on the end of the shaft 82 to urge the shaft 84 and 82 to rotate together. The spring just described constitutes a part of a clutch member whereby the shaft 84 may be rotated independent of the rotation of the shaft 82.

Fixed to the shaft 84 is a spur gear 89 meshing with a second spur gear 90 fixed upon a control shaft 91 rotatably mounted in the housing 8!. The control shaft BI is mounted in bear ings 92 and 93 and is urged toward downward movement (as shown in Fig. 3) by a spring 94, the downward movement causing an extension 85 of the gear 90 to bear against the end of a collar portion 96 secured in the housing. A pointer 91 is secured to the outer end of the control shaft 9| and exterior to the panel 83.

Rotatably mounted on the Collar portion 96 is a spur gear 98 which meshes with an idler ear 99 mounted upon shaft I00 in the housing. The idler gear 99 meshes with a gear Illl mounted upon shaft I02. The shaft I02 is rotatably mounted in the housing and carries a second gear H33 meshing with an internal gear 104 rotatably mounted in the housing 8|. The internal gear carries a pointer I which is moved with rotation of the gear I04 across the face of the dial panel. The dial 83 is suitably inscribed with figures indicating the number of cubic inches of fluid necessary to effect reciprocation of the member and rotation of the gear IE4 is adapted to move the pointer I05 across the inscribed face of the dial visually to indicate the volume of fluid to be pumped at any particular setting of the pointer. A control knob 10B is mounted upon the end of the shaft Hi2 and may be manually rotated to rotate the internal gear lbs and the spur gear 98.

A control arm H8 is rigidly fixed to the control shaft 9! and oscillated with reversing rotation of the shaft 9 I. The outer end of the control arm carries a bearing Ill adapted to depress a limit switch H2 mounted in the housing to energize one of the solenoids and effect reversal of the pump Ill. The spur gear 98 is provided with a device in the form of a bolt H3 which extends into the path of oscillation of the con trol arm H0. Reversal of the pump by contact of the control arm H0 with the limit switch H2 causes the control arm to oscillate in the opposite direction and bring the bearing 1 l I into contact with the device H3. Such a contact serves to move the control shaft 9| longitudinally of its axis of rotation and against a second limit switch 4 to energize the other solenoid and again to reverse the pump 10.

The position of the device H3 in the path'of oscillation of the control arm is, of course, dependent upon the position of the gear 98- and the gear may be rotated by means of the knob I I36 through the gears NH and 99, as previously described.

Actuation of the limit switch I I4 can be performed manually at any time by inward pressure of the pointer 91 to reverse the motor II].

It is clear that by rotation of the knob I08 the pointer I85 is moved along the scale of the dial until the desired volume of flow in the cylinder line is indicated, the volume, of course, being determined by the volume of fluid necessary to reciprocate the device in the cylinder 63 through a full stroke in one direction. Simultaneously with movement of the pointer I05 the device H3 is moved either toward or away from the limit switch H2 in the plane of the path of oscillation of the control arm 'I In to determine the amount of oscillation Of that arm necessary to effect successive reversal of the pump. The actual speed of reciprocation of the member and cylinder 63 is, of course, determined by the setting of the volume controls on the pump I!) but regardless of the speed of reciprocation my control device serves to effect reversal of the pump at the desired point in the stroke of the reciprocating member.

The inscribed dials I7 and 83 are mounted upon a control panel I20 Which also carries the gauges 65, 63 and I5 and knobs I5, I6, 85 and I06. The shafts I8 and I9 are rotatably mounted on the panel, the rod I8 being connected directly to the volume control I3 while the rod I 9 is connected to the volume control I4 through a series of spur gears I2I, I22 and I23 rotatably mounted in housing I2 5. Secured to the control panel I29 is a housing I25 in which a pair of ring gears I26 and I2! are rotatably mounted, the ring gear I26 meshing with a spur gear I28 fixed to the shaft I8 and the ring gear I21 meshing with a spur gear I29 fixed to the shaft I9. The ring gear I21 carries a pointer I38 movable around the dial I1 and the ring gear I2! carries a second pointer I 3| similarly movable around the dial. Rotation of the knob I5 which, for example, may be the volume control for the cylinder line, serves through the gears just mentioned not only to control the operation of the volume control I3 but also to move the pointer I3I over the inscribed face of the dial I! to indicate the volume of fluid moved by the pump in one direction. The pointer I36 associated with the jack line control indicates the volume moved by the pump through the jack line.

I claim:

1. A stroke-control apparatus for a recip-rocable member comprising reversible means for reciprocating the member, means for reversing the reversible means, a motor driven in forward and reverse in synchronism with the reciprocation of the member, a control shaft oscillated by the motor, actuating means for the reversing means, means for operating the actuating means carried by the control shaft and adapted to operate the actuating means at the end of an oscillation of the control shaft in one direction to reverse the reciprocating means, a device extending into the path of oscillation of the operating 'meansi'n theother direction and adapted to operate'tlie operating means upon contact with the operating means again to reverse the reciprocatin'g means, and manually operable setting means for "selectively moving the device to various points in the cating the member, means for reversing the reversible means, a motor driven in forward and reverse in synchronism with the reciprocation of the member, a control shaft oscillated by the motor, actuating means for the reversing means, means for operating the actuating means carried by the control shaft and adapted to operate the actuating means at the end of an oscillation of the control shaft in one direction to reverse the reciprocating means, a device extending into the path of oscillation of the operating means in the other direction and adapted to operate the opcrating means upon contact therewith again to reverse the reciprocating means, manually operable Setting means for selectively locating the device at various points in the path of oscillation of the operating means and manually operable means for oscillating the control shaft independent of the motor.

'3. A stroke-control apparatus for a 'reciproc'a ble member comprising reversible means for reciprocating the member, means for reversing the reversible means, a motor driven in forward and reverse in synchronism with the reciprocation of the member, a control shaft oscillated by the motor, actuating means for the reversing means, means for operating the actuating means carried by the control shaft and adapted to operate the actuating means at the end of an oscillation of the control shaft in one direction to reverse the reciprocating means, a device extending into the path of oscillation of the operating means in the other direction and adapted to operate the operating means upon contact therewith again to reverse the reciprocating means, manually operable setting means for selectively moving the device to various points in the path of oscillation of the operating means, a graduated control panel, and indicating means operated by the setting means to indicate on the panel the location of the device.

4. A stroke-control apparatus for a reciproca- -ble member comprising reversible means for reciprocating the member, means for reversing the reversible means, a motor driven in forward and reverse in synchronism with the reciprocationoi the member, a control shaft oscillated by the motor, actuating means for the reversing means, means for operating the actuating-means carried by the control shaft and adapted to operate the actuating means at the end of an oscillation of the control shaft in one direction to reverse the reciprocating means, a device extending into thepath of oscillation of the operating means in the other direction and adapted to operate the operating means upon contact therewith again to reverse the reciprocating means, manually operable setting means for selectively moving the device to various points in the path of oscillation of the operating means, a graduated control panel,indicating means operated by the setting means to indicate on the panel the loby the control shaftandadapted-to operate-the actuating means at the end of an oscillation of the control shaft in one direction to reverse the reciprocating means, a device extending into the path of oscillation of the operating means in the other direction and adapted to operate the operating means upon contact therewith again to reverse the reciprocating means, manually operable setting means for selectively moving the device to various points in the path of oscillation of the operating means, a graduated control panel, indicating means operated by the setting means to indicate on the panel the location of the device, a pointer on the panel aligned with the operating means and oscillated by the control shaft to indicate on the panel the position of the operating means, and manually operable means on the panel for oscillating the control shaft independent of the motor.

6. A stroke-control apparatus for a reciprocable member comprising reversible means for reciprocating the member, means for reversing the reversible means, a motor driven in forward and reverse in synchronism with the reciprocation of the member, a control shaft oscillated by the motor, actuating means for the reversing means, means for operating the actuating means carried by the control shaft and adapted to operate the actuating means at the end of an oscillation of the control shaft in one direction to reverse the reciprocating means, a device extending into the path of oscillation of the operating means in the other direction and adapted to operate the operating means upon contact therewith again to reverse the reciprocating means, manually operable setting means for selectively moving the device to various points in the path of oscillation of the operating means, a graduated control panel, a pointer movable around the panel, a knob on the panel mounted on a rotatable setting shaft, a first gear on the setting shaft for moving the pointer and a second gear on the setting shaft for moving the device to various points in said path.

7. A stroke-control apparatus for a reciprocable member comprising reversible means for reciprocating the member, means for reversing the reversible means, a motor driven in forward and reverse in synchronism with the reciprocation of the member, a control shaft oscillated by the motor, actuating means for the reversing means, means for operating the actuating means carried by the control shaft and adapted to operate the actuating means at the end of an oscillation of the control shaft in one direction to reverse the reciprocating means, a rotatably mounted gear, a device mounted on the rotatable gear and extending into the path of oscillation of the operating means in the other direction and adapted to operate the operating means upon contact therewith again to reverse the reciprocating means, a graduated control panel, a pointer mounted on an internally toothed gear and movable around the panel, a knob on the panel mounted on a rotatable setting shaft, a first gear on the setting shaft meshing with the internal gear and a second gear on the shaft for rotating the gear carrying the device.

8. In combination with a reciprocable member and electrically reversible means for reciprocating the member, a control device for the reciprocating means comprising a housing, a control shaft rotatably mounted in the housing and oscillated in synchronism with reciprocation of the member, a pair of limit switches in the housing for reversing the reciprocating means, a control arm carried by the shaft and adapted to operate one of said switches at the end of an oscillation of the control arm in one direction, a device extending into the path of oscillation of the control arm in the other direction and adapted to cause operation of the other switch upon contact of the control arm therewith, and manually operable setting means for selectively moving the device to various points in the path of oscillation of the control arm.

9. In combination with a reciprocable member and electrically reversible means for reciprocating the member, a control device for the reciprocating means comprising a housing, a control shaft rotatably mounted in the housing and oscillated in synchronism with reciprocation of the member, a pair of limit switches in the housing for reversing the reciprocating means, a control arm carried by the shaft and adapted to operate one of said switches at the end of an oscillation of the control arm in one direction, a gear in the housing rotatably mounted about the axis of rotation of the control shaft, a device carried by the gear and extending into the path of oscillation of the control arm in the other direction and adapted to cause operation of the other switch upon contact of control arm therewith, a setting shaft rotatably mounted in the housing, and a gear mounted on the setting shaft for rotating the gear carrying the device for selectively moving the device to various points in the path of oscillation of the control arm.

10. In combination with a reciprocable member and electrically reversible means for reciprocating the member, a control device for the reciprocating means comprising a housing, a control shaft rotatably mounted in the housing and oscillated in synchronism with reciprocation of the member, a pair of limit switches in the housing for reversing the reciprocating means, a control arm carried by the shaft and adapted to operate one of said switches at the end of an oscillation of the control arm in one direction, a gear in the housing rotatably mounted about the axis of rotation of the control shaft, a device carried by the gear and extending into the path of oscillation of the control arm in the other direction and adapted to cause operation of the other switch upon contact of the control arm therewith, a graduated control panel on the housing, a pointer movable around the panel and carried by an internally toothed gear rotatably mounted in the housing, a knob on the panel and mounted on a rotatable setting shaft, a first gear on the setting shaft meshing with the internally toothed gear, and a second gear on the setting shaft for rotating the gear carrying the device, rotation of the knob being adapted to move the device to various points in the path of oscillation of the control arm and simultaneously to move the pointer around the panel.

11. In combination with a reciprocable member and electrically reversible means for reciprocating the member, a control device for the reciprocating means comprising a housing, a control shaft rotatably mounted in the housing, means for oscillating the control shaft in synchronism with reciprocation of the member, a pair of limit switches in the housing for reversing the reciprocating means, a control arm carried by the shaft and adapted to operate one of said switches at the end of an oscillation of the control arm in one direction, a gear in the housing rotatably mounted about the axis of rotation of the control shaft, a device carried by the gear and extending into the path of oscillation of the control arm in the other direction and adapted to cause operation of the other switch upon contact of the control arm therewith, a graduated control panel on the housing, a pointer movable around the panel and carried by an internally toothed gear rotatably mounted in the housing, a knob on the panel mounted on a rotatable setting shaft, a first gear on the setting shaft meshing with the internally toothed gear, a second gear on the setting shaft for rotating the gear carrying the device, rotation of said setting shaft being adapted to move the device to various points in the path of oscillation of the. control arm and to move the pointer around the panel, a drive shaft interposed between the oscillating means and the control shaft and clutch means for rotating the drive shaft to oscillate the control shaft independent of the oscillating means.

12. In combination with a reciprocable member and electrically reversible means for reciprocating the member, a control device for the reciprocating means comprising a housing, a control shaft rotatably mounted in the housing and movable therein longitudinally of its axis of rotation, means urging the control shaft toward movement in one longitudinal direction, means for oscillating the control shaft in synchronism with reciprocation of the member, a pair of limit switches in the housing for reversing the reciprocating means, a control arm carried by the shaft and adapted to contact one of the said switches at the end of an oscillation of the control arm in one direction, a device extending into the path of oscillation of the control arm in the other direction and adapted to contact the control arm to move the shaft longitudinally in the housing in the other direction and into operating contact with the other switch, a graduated control panel on the housing, a pointer movable around the panel and carried by an internally toothed gear 1 rotatably mounted in the housing, a knob on the panel and mounted on a rotatable setting shaft, a first gear on the setting shaft meshing with the internally toothed gear, a second gear on the setting shaft, an idler gear meshing with the second gear and meshing with the gear carrying the device, rotation of said setting shaft being adapted to move the device to various points in the path of oscillation of the control arm and to move the pointer about the panel.

13. In a combination with a reciprocable member and electrically reversible means for reciprocating the member, a control device for the reciprocating means comprising a housing, a control shaft rotatably mounted in the housing and movable therein longitudinally of its axis of rotation, means urging the control shaft toward movement in one longitudinal direction, means for oscillating the control shaft in synchronism with reci rocation of the member, a pair of limit switches in the housing for reversing the reciproeating mea s, a control arm carried by the shaft and adapted to contact one of the said switches at the end of an oscillation of the control arm in one direction, a device extending into the path of oscillation of the control arm in the other direction and adapted to contact the control arm to move the shaft longitudinally in the housing in the other direction and into operating contact with the other switch, a graduated control panel on the housing, a pointer movable around the panel and carried by an internally toothed gear rotatably mounted in the housing, a knob on the panel and mounted on a rotatable setting shaft, a first gear on the setting shaft meshing with the internally toothed gear, a second gear on the setting shaft, anidler gear meshing with the second gear and meshing with the gear carrying the device, rotation of said setting shaft being adapted to move the device to various points in the path of oscillation of the control arm and to move the pointer about the panel, a drive shaft interposed between the oscillating means and the control shaft and geared to the control shaft and clutch means on the control panel for rotating the drive shaft to oscillate the control shaft independent of the oscillating means.

1 4. In combination with a reciprocable member and electrically reversible means for reciprocating the member, a control device for the reciprocating means comprising a housing, a control shaft rotatably mounted in the housing and movable therein longitudinally of its axis of rotation, means urging the control shaft toward movement in one longitudinal direction, means for oscillating the control shaft in synchronism with reciprocation of the member, a pair of limit switches in the housing for reversingthe reciprocating means, a control arm carried by the shaft and adapted to contact one of the said switches at the end of an oscillation of the control shaft in one direction, a device extending into the path of oscillation of the control arm in the other direction and adapted to contact the control arm to move the shaft longitudinally in the housing in the other direction and into operating contact with the other switch, a graduated control panel on the housing, a pointer movable around the panel and carried by an internally toothed gear rotatably mounted in the housingja knob on the panel and mounted on a rotatable setting shaft, a first gear on the setting shaft meshing with the internally toothed gear, a second gear on the setting shaft, an idler gear meshing with the second gear and meshing with the gear carrying the device, rotation of said setting shaft being adapted to move the device to various points in the path of oscillation of the control arm and to move the pointer about the panel, and a second pointer on the panel mounted on the end of the control shaft and aligned with the operating means to indicate on the panel the position of the operating means, manual pressure on said second pointer being adapted to move the control shaft longitudinally against the urging means to operate said other switch.

15. In a hydraulic circuit including a reversible pump and means for controlling the volume of fluid moved by the pump in forward and in reverse, a control comprising a control panel, a graduated dial on the panel, pointers movable around the dial a knob rotatably mounted on the pa el an connec d t a o n er a d to o of the volume control means, a second knob rotatably mounted on the panel and connected to another pointer and to the other volume control means, rotation of a knob being adapted to operate a volume control means and to move a pointer on the dial, a second graduated dial on the panel, a third pointer movable around the second dial, adjustable means mounted on the panel for reversing the pump and a third knob rotatably mounted on the panel and connected to the third pointer and to the reversing means, rotation of the third knob being adapted to move the reversing means for controlling the operation thereof and to move the third pointer on the second dial.

16. In a hydraulic circuit including a reversible pump, a control comprising a control panel, a graduated dial on the panel, a pair of ring gears rotatably mounted on the panel concentric with the dial, a pointer on each gear and movable around the dial, a pair of shafts rotatably mounted on the panel, a spur gear on each shaft meshing with a different one of said ring gears, means for controlling the volume of fluid moved by the pump in forward and means for controlling the volume of fluid moved by the pump in reverse, each of said shafts being connected to a different one of said volume control means, whereby rotation of each of said shafts is adapted to operate the volume control means connected thereto and to move a pointer around the dial.

17. In a hydraulic circuit including a reversible pump, a control comprising a control panel,

a graduated dial on the panel, a pair of ring gears rotatably mounted on the panel concentric with the dial, a pointer on each ring gear and movable around the dial, a pair of shafts rotatably mounted on the panel, a spur gear on each shaft meshing with a different one of said ring gears, means for controlling the volume of fluid moved by the pump in forwardand means for controlling the volume of fluid moved by the pump in reverse, each of said shafts being connected to a different one of said volume control means; whereby rotation of each of said shafts is adapted to operate the control means connected thereto and to move a pointer around the dial, a second graduated dial on the panel, a third pointer movable around the second dial, a first'gear carrying the third pointer. adjustable means for reversing the pump, a second gear for adjusting the reversing means, a third shaft rotatably mounted on the panel, a third gear carried by the third shaft and meshing with the second gear,a fourth gear on the third shaft meshing with the first gear carrying the third pointer, whereby rotation of said third shaft is adapted to adjust the reversing means and to move the third pointer on the second dial.

18. In a hydraulic circuit including a reversible pump, and a metering motor driven by the pump, a control comprising a control panel, a graduated dial on the panel, a pair of ring gears rotatably mounted on the panel concentric with the dial, a pointer on each gear and movable around the dial, a pair of shafts rotatably mounted on the panel, a spur gear on each shaft meshing with a different one of said ring gears, means for controlling the volume of fluid moved by the pump in forward and means for controlling the volume of fluid moved by the pump in reverse, each of said shafts being connected to a volume control means, whereby rotation of said shafts is adapted to operate the volume control means connected thereto and to move a pointer around the dial, a second graduated dial on the panel, a third pointer movable around the second dial, a control shaft oscillated by the motor, a control arm mounted on the control shaft and carrying means for reversing the pump,

around the dial,

an externally toothed gear rotatably mounted on the panel, means for operating the reversing means carried by the last-mentioned gear, an internally toothed gear rotatably mounted on the panel and carrying the third pointer, a third shaft rotatably mounted on the panel and carrying a first gear meshing with the externally toothed gear and carrying a second gear meshing with the internally toothed gear, whereby rotation of said shaft is adapted to move the operating means and to move the third pointer on the second dial.

19. In a hydraulic circuit including a reversible pump, and a metering motor driven by the pump, a control comprising a control panel, a graduated dial on the panel, a pair of ring gears rotatably mounted on the panel concentric with the dial, a pointer on each gear and movable a pair of' shafts rotatably mounted on the panel, a spur gear on each shaft meshing with a different one of'said ring gears, means for controlling the volume of fluid moved by the pump in forward and means for controlling the volume of fluid moved by the pum in reverse, each of said shafts being connected to a different one of said volume control means, whereby rotation of said shafts is adapted to operate the volume control means connected thereto and to move a pointer around the dial, a second graduated dial on the panel, a third pointer movable around the second dial, a control shaft oscillated by the motor, a control arm mounted on the control shaft and carrying means for reversing the pump, an externally toothed gear rotatably mounted on the'panel, means for operating the reversing means carried by the last-mentioned gear, an internally; toothed gear rotatably mounted on the panel and carrying the third pointer, a shaft rotatably mounted on the panel, a first gear on the last-mentioned shaft meshing with the externally toothed gear, a second gear on the last-mentioned shaft meshing with the internally toothed gear, rotation of said last-mentioned shaft being adapted to move the operating means and to move the third pointer on the second dial,'a second shaft rotatably mounted on the panel and connecting the control shaft with the motor and means for rotating the second shaft to oscillate the control arm independent of the motor.

PAUL S. JACKSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,156,433 Pratt Oct. 12, 1915 2,191,552 Zimmerman Feb. 27, 1940 2,259,587 Rush g Oct. 21, 1941

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