US1000071A - System of control. - Google Patents

Description

H W. CHENEY. SYSTEM OF GONTROL. APPLICATION rum) DEC. a1, 1906.

Patented Aug. 8, 1911.

H. W. CHENEY. SYSTEM OF CONTROL. APPLIOATION FILED DBO. 31, 1900.

1,000,071, Patented Aug. 8,1911.

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COLUMBIA PLANOGRAPH cu., WASHINGTON. n. c.

H. W. CHENEY. SYSTEM OF CONTROL.

APPLICATION FILED DBO. 31, 1906. 1,000,071

Patented Aug. 8, 1911.

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COLUMBIA PLANOGRAPH C0,, WASHINGTON, I:v C.

UNITED STA'IES PATENT ()FIGE.

HERBERT W. CHENEY, OF NORWOOD, OHIO, ASSIGNOR T0 ALLIS-CHALMERS COMPANY, A CORPORATION OF NEW JERSEY, AND THE BULLOCK ELECTRIC MANUFACTURING COMPANY, A CORPORATION OF OHIO.

SYSTEM OF CONTROL.

To all whom it may concern:

Be it known that I, HERBERT WV. CHENEY, citizen of the United States, residing at Norwood, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Systems of Control, of which the following is a full, clear, and exact specification.

My invention relates to fluid pressure systems, and especially to those fluid pressure systems in which the pressure is kept within predetermined limits by means of a pump intermittently driven by an electric motor.

In fluid pressure systems such as are used for air brakes and other fluid operated mechanism, it is necessary that a source of fluid supply at approximately constant pressure be maintained. Various arrangements for maintaining this constant pressure of the source of fluid supply have been devised, and my present invention is an improvement on such arrangements.

The object of my invention is to provide a system of this sort which is certain in operation and which is especially applicable when an alternating current motor, such as an induction motor, is used to drive the pump.

In controllers for electric motors, and especially in potential starters for induction motors, it is often advantageous that the normal movement be always in the same di rection, so that the controller will not pass through its starting positions when moving from the running to the oft positions. My invention contemplates the use of such a controller, which is arranged to be moved by fluid-actuated means through different parts of its movement when the pressure in the system increases above and decreases below its normal value.

Other objects of my invention will appear hereinafter.

\Vith these objects in view my invention consists of the combination in a fluid pressure system, of an electric motor, a controller for said motor movable always in the same direction, and fluid-actuated means for operating said controller.

In another aspect my invention comprises the combination in a fluid pressure system of a reservoir, a fluid-operated switch, and means for admitting pressure to operate said Specification of Letters Patent.

Application filed December 31, 1906.

Patented Aug. 8, 1911.

Serial No. 350,212.

switch in response to variation of the pressure in said reservoir and for shutting off said fluid pressure by movement of the switch.

In another aspect my invention consists of the combination in a fluid pressure system of a. reservoir, and a valve arranged to open when the pressure in the reservoir either rises above or falls below certain predetermined limits.

In still another aspect my invention comprises the combination in a fluid pressure system of a reservoir, fluid-actuated means, and means for admitting fluid pressure to actuate said fluid-actuated means in one direction upon a variation in the pressure in the reservoir either way from normal and for shutting off said fluid pressure upon the desired movement of the fluid actuated means.

From another point of View my invention comprises the combination of a rod arranged to have both a longitudinal and a rotating movement, and a valve arranged to be operated upon either of said movements of the rod.

In a more specific aspect my invention consists of the combination in a fluid pressure system, of a reservoir, fluid-operated means controlling the supply of fluid to said reservoir, and a valve arranged to admit fluid pressure to said fluid-operated means when the pressure in the reservoir either increases or decreases beyond predetermined limits.

In a still more specific aspect my invention comprises the combination in a fluid pressure system, of a reservoir, a pump for supplying said reservoir, an electric motor for driving said pump, a controller for said motor, fluid-actuated means for operating said controller, and a valve for admitting fluid pressure to said fluid-actuated means, said valve being arranged to be opened when the fluid pressure in the reservoir either falls below or rises above predetermined limits and to be closed as the controller is moved into running or ofl position.

Other features of novelty will appear from the description and drawings and will be particularly pointed out in the claims.

Figure l is a diagrammatic view showing the system as a whole. Fig. 2 is a plan view of the controller operating means and the elevation of the structure shown in Fig. 2; Fig. 4 is a section on the line 4-4 of Fig. 2; Fig. 5 is a section on the line of Fig. 2; Fig. (5 is a section on the line (3 6 of Fig. 2; Fig. 7 is an end elevation of the structure shown in Fig. 2; Fig. 8 is a section on the line 8-8 of Fig. 2; Fig. 9 is an enlarged isometric view of the cut-away portion of the operating rod of the governing device; and Fig. 10 is a diagram showing the electrical connections of the controller.

Referring to the drawings, 20 is a reservoir, preferably containing compressed air which may be drawn from the reservoir through a pipe 21. for any desired purpose,

such as for operating airbrakes. The reservoir 20 is supplied by means of a fluid pump or air compressor 22 driven, in the arrangement shown, by a three-phase induction motor 23. This motor is here shown with a squirrel-cage rotor.

The primary circuit of the motor 23 is supplied from any desired source through the main switch 24 and a controller This controller. the connect-ions of which are best shown in Fig. 10, is here illustrated as a potential starter, which in one or more starting positions connects the motor terminals to the source through auto-transformer windings 26 and 27, and in the running position disconnects the auto-transformer windings and connects the motor terminals directly to the mains. In this type of controller, it is desirable that the controller when being moved from running position to off position should not pass through a starting position, and so the controller is arranged to move continuously forward as shown by the arrow in Fig. 1. The particular controller illustrated comprises a rotatable drum 28 having duplicate halves respectively co-acting with two diametrically opposite sets of stationary contact fingers during one complete operation of the controller, and with the opposite sets during the next complete operation of the controller. Such a controller has duplicate off, starting and running positions as indicated on the ratchet wheel in Fig. 1. The controller hereshown passes through but one starting position between the off and. the running positions, though any desired number of starting positions may be used. In the arrangement shown analogous positions are 180 apart. The particular construction and arrangement of the controller drum however forms no part of my present invention, which is equally applicable to other forms of controllers, such for instance as those having but one off and one running position with any desired number of starting positions between them.

The shaft 29 on which the drum 28 is mounted extends out of the controller to a fluid pressure responsive device, and is supported in bearings 30 extending from the base of the latter. This pressure responsive device consists of means for actuating the controller 25, and goy erning means for said controlleractuating means, and chiefly comprises two cylinders 31 and provided with pistons and 34. These pistons are biased in one direction, as by springs 35 and 3G, and are movable in the other direction by fluid pressure from the reservoir 20. If desired the piston 33 may be moved by fluid pressure from any other desired source. The cylinder 32 is always in connection pneumatically with the reservoir 20 through a pipe 37, chamber 38 and passage 39, best shown in Figs. 2 and (3. The piston 34 is connected to a rod 40, the rod and the piston being movable together longitudinally, while the rod may be rotated without moving the piston. The connection for allowing this is plainly shown in Fig. 5. A pinion 41 is mounted on the rod 40 to turn therewith, provision being made for longitudinal movement of the rod 40 independent of the pinion 41, as by means of a spline.

A gear segment 42 meshes with he pinion 41, said gear segment being pivoted on the base of the fluid pressure responsive device at 48. A roller 44 is carried by the gear segment 42 and rides in the groove of a grooved cam 45 fixed on the shaft 29. The cam faces of this groove are arranged to act on the roller 44 to rotate the rod 40 through a suitable angle, here shown as 90, when the controller is moved to running position, and back to its initial position when the controller is moved to OH position. The rod 40 is cut away, as best shown in Fig. 9, the two cut-away surfaces 47 and 48 being at right angles to each other and terminated by inclined planes 50 and 51. and 52 and 58 respectively. The two cut-away surfaces are displaced from each other longitudinally of the rod 40 as shown so that the inclined plane 50 is adjacent the surface 48 and the inclined plane 53 adjacent the surface 47. Preferably the edges between the surfaces 50 and 48, and 53 and 47 are rounded off, as indicated at 50 and 53". Other edges may be rounded off if desired.

A. valve 54 is spring-pressed to closed position shown in Figs. 1, 5 and 6, and has a stem 55 which can be engaged by the inclined planes at the ends of the cut-away surfaces 47 and 48 to open said valve. 1V hen either surface 47 or 48 is under the valve stem 55, the valve 54 is closed, but when any of the inclined planes at the ends of said surfaces come under said valve stem, the latter rides up on said inclined plane and said valve is opened. By longitudinal movement of the rod 40, due to variation in pressure in the reservoir 20, the valve 54 1S opened by one of the inclined planes 50 or 53, whlle upon rotating movement of rod 40, due to movement of the controller 25, the valve 54 is allowed .to close because the inclined plane 50 or 53 slides from under the valve stem 55 and is replaced by the lower cut-away surface 48 or 47 as the case may be.

Valve 54 when open connects the two chambers 56 and 57, as best shown in Figs. 1, 5 and 6. The chamber 56 is a branch from the chamber 38, while the chamber 57 leads to a chamber 58 similar to the chamber 38 and directly beneath it, as seen in Fig. 6. The chamber 58 is connected to the chamber 59 by a passageway 60. Chambers 61 and 62 are directly connected to the interior of the cylinder 31 by means of the passageways 63 and 64 respectively. A chamber 65 is in direct connection with the atmosphere through an opening 66, the effective size of which is adjustable by means of aneedle valve 67. The chambers 59 and 61 may be connected by opening a valve 68, spring-pressed toward closed position. The chambers 62 and 65 may be similarly connected by means of a similar valve 69.

The piston 33 is mounted at the end of a piston rod 70. To the other end of this rod is pivoted a link 71 which joins it to an arm 72 loosely mounted on the shaft 29. The pin joining the link 71 and the arm 72 carries a pawl 73 which is springpressed into cooperative engagement with a ratchet wheel 74 fixed on the shaft 29 of the controller 25. When fluid pressure is admitted to the cylinder 31 through the valves 54 and 68, the piston 33 and rod 70 are moved to the left to actuate the ratchet and controller one step forward, the controller and ratchet remaining in such position while the air escapes from the cylinder 31 through the valve 69 and allows the piston 33, the rod 70 and the pawl 73 to return to their initial positions, as explained below.

hen the rod 70 reaches its limits of movement, the valves 68 and 69 are operated by means of a pin 75 mounted on the rod 70 and extending into the slot of slotted member 76. As here shown the pin 7 5 is an extension of the pin by which the rod 70 and the link 71 are joined. The member '76 is one end of a rod 77, the other end of which is cut away at 78 and 79 as best shown in Fig. 8. These cut-away portions are on opposite sides of the rod 77 and are displaced slightly from each other longitudinally of the rod, as shown. The valve stem 80 of the valve 68 cotiperates with the cut-away portion 78 while the valve stem 81 of valve 69 cooperates with the cutaway portion 79. hen the piston 33 is in its normal position, the cut-away portion 79 is directly under the valve stem 81 allowing the valve 69 to be closed, while because the cut-away portion 78 is not directly under the valve stem 80 the valve 68 is held open. hen the piston 33 has been moved to the other end of its movement, the pin 75 strikes the other end of the slot in the member 76 and moves the rod 77 slightly endwise to open the valve 69 and to allow the valve 68 to close. Upon the return of the piston 73 to its normal position, the rod 77 is moved back again to its initial position, thus again opening valve 68 and closing valve 69.

The operation of the system is as follows :VVhen the pressure in the reservoir 20 is at its normal value, the various parts are in their normal positions. Upon fall of pressure in the reservoir 20 the spring 36 moves the piston 34 to the right. \Vhen the pressure has decreased to the predetermined limit for which the apparatus is set, the inclined plane 50 raises the valve stem 55 and opens the valve 54. This admits fluid. pressure from the chamber 56 to the chamber 57, whence it passes through chamber 58, passageway 60, chamber 59, the open valve 68, chamber 61, and passageway 63 to the cylinder 31 and moves the piston 33 to the left against the action of the spring 35. This movement of the piston 33 moves the controller from its off to its starting position. In starting position the mo tor 23 is connected to the auto-transformer windings 26 and 27 and the latter to the source of supply, thus impressing an electromotive force on the motor which is less than that of the line. Just as the controller reaches its starting position, the pin 75 ioves the rod 77 to close the valve 68 and open the valve 69, thus disconnecting the cylinder 31 from the reservoir 20 and connecting it to the atmosphere through the opening 66. The spring 35 now forces the piston 33 back toward its initial position, the time required for this backward movement being adjustable by the needle valve 67.

hen the piston 33 reaches its initial position, the pin 75 moves the rod 77 back to its initial position again opening valve 68 and closing valve 69. This again admits fluid pressure from the reservoir 20 to the cylinder 31 and causes the piston 33 to again move to the left to now move the controller 25 from starting to running position, disconnecting the auto-transformer windings 26 and 27 and connecting the motor terminals directly to the mains. As the controller is moved into running position the cam 45 moves the roller 44 and through it the gear segment 42 and pinion 41 to rotate the rod 40. This causes the inclined plane 50 to pass from under the valve stem 55 and brings the surface 48 thereunder, thus allowing said valve to close to disconnect the cylinder 31 from the reservoir 20. Also the movement of the controller to running position again causes the rod 77 to be moved to close the valve 68 and open Valve 69, thus disconnecting the cylinder 31 from the reservoir 20 at a second point and opening the cylinder 31 to the atmosphere through the opening 66. The piston 33 now returns to its initial position and upon reaching such position causes the rod 77 to be moved to open valve (38 and close valve 69. This time, however, the opening of valve 68 does not cause a movement of the piston 33 because the valve 54 is closed.

IVhen the controller is in running position the motor 23 drives the pump 22 to supply air or other fluid to the reservoir '20. As the pressure in the reservoir 20 rises, the piston 34 is moved to the left against the action of the spring 36 until, when said pressure obtains its predetermined maXimum, the inclined plane 53 raises the valve stem 55 and again opens the valve 54. This again admits fluid pressure from the reservoir 20 through the valves 54 and 68 to the cylinder 31, and causes the piston 33 to again move to the left against the action of spring 35. This time this movement of the piston 33 moves the controller 25 in the same di rection as before from the running position to the off position, disconnecting the motor 23 to stop said motor together with the pump 22. The movement of the controller to off position also operates the gear segment 42 and pinion 41 through the cam 45 and roller 44 to rotate the rod 40 back to its former position, thus causing the inclined plane 53 to pass from under the valve stem 55 and to be replaced by the surface 47 to allow the valve 54 to close to cut off the connection between the cylinder 31 and the reservoir 20. As the controller is moved into ofl' position, the pin 75 again causes the valve (39 to open and the valve 68 to close, this also disconnecting the cylinder 31 and reservoir '20 and in addition connecting said cylinder to the atmosphere through the opening 66. The piston 33 thus again returns to its initial position under the action of the spring 35 and upon reaching it again opens the valve 68 and closes the valve 69 to prepare for the next cycle of operations.

The above cycle is repeated as often as the pressure in the reservoir falls to its lower limit and rises to its upper limit. In the diagrammatic arrangement shown in Fig. 1, some of the parts are omitted or modified in order to furnish a clear understanding of the invention as a whole, and the detailed description which is given above is given primarily in relation to the arrangement shown in the other figures.

Although I have described my invention particularly in reference to air pressure systems, it is equally adapted to be used with any other fluid pressure system, whether the fluid be liquid or aeriform. My invention is also capable of use in connection with those systems in which a fluid is exhausted from, as well as to those in which it is supplied to, a container.

Instead of using cylinders and pistons for getting the desired movement in response to variations of pressure in the reservoir, it is possible in some cases to use diaphragms which flex in pro-portion to the difference between the pressures on their opposite sides.

Many other modifications may be made in the arrangements herein shown and described and in the following claims I aim to cover all such which come within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent is 1. In a fluid pressure system, the combination of a reservoir, a valve, and valve operating means for moving said valve from closed to open position upon either increase or decrease of the fluid pressure in the reservoir.

2. In a fluid pressure system, the combination of a reservoir, and a valve arranged to open in the same way when the pressure in the reservoir either rises above or falls below predetermined limits.

3. In a fluid pressure system, the combination of a reservoir, a chamber, and valvular means for admit-ting fluid pressure to said chamber when the pressure in the reservoir either increases above or decreases below its normal value.

4. In a fluid pressure system, the combination of a reservoir, fluid-actuated means biased in one direction, and valvular means for admitting fluid pressure to actuate said fluid-actuated means in the other direction upon either rise or fall of the pressure in the reservoir from normal.

5. In a fluid pressure system, the combination of a reservoir, fluid-actuated means op erable in two directions, valvular means for admitting fluid pressure to actuate said fluid-actuated means in the same direction upon a variation in the pressure in the reservoir either way from normal, and a de vice controlled by said fluid-actuated means.

6. In a fluid pressure system, the combination of a reservoir, fluid-actuated means operable in two directions, a valve for admitting fluid pressure to actuate said fluidactuated means in one direction, valve operating means for opening said valve upon either increase or decrease of pressure in said reservoir beyond predetermined limits, and a device controlled by said fluid-actuated means.

7 In a fluid pressure system, the combination of a reservoir, fluid-actuated means biased in one direction, means for admitting pressure to actuate said fluid-actuated means in the other direction upon either rise or fall of the pressure in the reservoir from normal and for shutting off said fluid pressure upon the desired movement of the fluid-actuated means, and a device controlled by said fluidactuated means.

8. In a fluid pressure system, the combination of a reservoir, fluid-actuated means operable in two directions, means for admitting fluid pressure to actuate said fluid-actuated means in the same direction upon a variation in the fluid pressure in the reservoir either way from normal and for shutting off said fluid pressure upon the desired movement of the fluid-actuated means, and a device controlled by said fluid-actuated means.

9. In a fluid pressure system, the combination of a reservoir, fluid-actuated means operable in two directions, a valve for admitting fluid pressure to actuate said fluidactuated means in one direction, means for opening said valve upon either increase or decrease of pressure in said reservoir beyond predetermined limits and for closing said valve upon the desired movement of the fluid-actuated means, and a device controlled by saidfluid-actuated means.

10. In a fluid pressure system, the combination of a reservoir, fluid-operated means for controlling the supply of fluid to said reservoir, and a valve arranged to admit fluid pressure to operate said fluid-operated means in the same direction when the pre sure in the reservoir either increases above or decreases below its normal value.

11. In a fluid pressure system, the combination of a reservoir, a pump for supplying said reservoir, fluid-operated means for controlling the operation of said pump, a one way valve for admitting fluid pressure 'to said fluidoperated means, and means responsive to the pressure in the reservoir for opening said valve when sa1d pressure departs from normal in either direction.

12. In a fluid pressure system, the combination of a reservoir, a pump for supplying said reservoir, a motor for driving said pump, fluid-operated means for controlling the supply of energy to said motor, a valve for admitting fluid pressure to operate said fluid-operated means always in one direction, and means for opening said valve upon either rise or fall of pressure in the reservoir from normal.

13. In a fluid pressure system, the combination of a reservoir, a pump for supplying said reservoir, driving means for said pump, fluid-operated means for controlling the operation 01": said driving means, a valve for admitting pressure to said fluid-operated means, and means responsive to fluid-pressure in the reservoir for opening said valve when said pressure departs from normal in either direction and for closing said valve when the fluid-operated means has accomplished its work.

14. In a fluid pressure system, the combination of a reservoir, a pump for supplying said reservoir, a motor for driving said pump, fluid-operated means for controlling the supply of energy to said motor, a valve for admitting fluid pressure to said fluidoperated means, and means for opening said valve upon either rise or fall of the pressure in the reservoir from normal and for closing said valve when the fluid-operated means has accomplished its function.

15. In a fluid pressure system, the combination of a reservoir, a pump for supplying said reservoir, an electric motor for driving said pump, a controller for said motor, fluidactuated means for operating said controller, and a valve for admitting fluid pressure to said fluid-actuated means, said valve being arranged to be opened to connect the same parts when the pressure in the reservoir either falls below or rises above certain predetermined limits.

16. In a fluid pressure system, the coming said reservoir, an electric motor for driving said pump, a controller for said motor, fluid-actuated means for operating said controller, and a valve for admitting fluid pressure to said fluid-actuated means, said valve being arranged to be opened when the fluid pressure in the reservoir either falls below or rises above predetermined limits and to be closed as the controller is moved into running or off positions.

17.. In a fluid pressure system, the combination of a reservoir, a pump for supplying said reservoir, an electric motor for driving said pump, a controller for said motor, fluidactuated means for operating said controller, and a Valve for admitting fluid pressure to said fluid-actuated means, said valve being arranged to be opened when the fluid pressure in the reservoir departs from normal and to be closed when the controller is moved to a predetermined position.

18. In a fluid pressure system, the combination of a reservoir, a pump supplying said reservoir, an electric motor for driving said pump, a controller for said motor, fluidactuated means for operating said controller, and means for admitting fluid pressure to said fluid-actuated means to operate it in the same direction when the fluid pressure in the reservoir either falls below or rises above normal.

19. In a fluid pressure system, the combination of a reservoir, a pump supplying said reservoir, an electric motor for driving said pump, a controller for said motor, fluidactuated means for operating said controller, and means for admitting fluid pressure to said fluid-actuated means when the pressure in the reservoir either falls below bination of a reservoir, a pump for supplyor rises above normal and for shutting off said fluid pressure by the movement of the controller to running or ofl' positions.

20. In a fluid pressure system, the combination of a reservoir, a pump supplying said reservoir, an electric motor for driving .Jaid pump, a controller for said motor, fluidactuated means for operating said controller, and means for admitting fluid pressure to said fluid-actuating means \vhenthe pressure in the reservoir departs from normal and for shutting off said fluid pressure by a movement of the controller.

21. In a'fluid pressure system, the combination of a reservoir, a pump for supplying said reservoir, a motor for operating said pump, a cylinder and piston controlling said motor, and valvular means for admitting fluid pressure into said cylinder upon the same side of said piston upon either rise or fall of the pressure in the reservoir.

22. In a fluid pressure system, the combination of a reservoir, a pump for supplying said reservoir, a motor for operating said pump, a cylinder and piston controlling sa1d motor, and means for admitting fluid pressure into said cylinder upon the same side of said piston upon either rise or fall of the pressure in the reservoir and for exhausting said fluid pressure from said cylinder upon the desired movement of the piston.

23. In a fluid pressure system, the combination of a reservoir, a pump for supplying said reservoir, a cylinder and piston governing the operation of said pump, a valve for admitting pressure into one end of said cylinder, and means for opening said valve upon either rise or fall of the pressure in the reservoir.

24. In combination, a rod arranged to have both a longitudinal and rotating movement, a valve arranged to be operated upon either of said movements of the rod, and means for moving said rod longitudinally and rotatively.

25. In a fluid pressure system, the combination of a fluid-operated switch, a rod arranged to have both a longitudinal and a rotating movement, a valve governing the admittance of fluid pressure to operate said switch and arranged to be operated upon either of said movements of the rod, and means for moving said rod both longitudinally and rotatively.

26. In a fluid pressure system, the combination of a reservoir, a fluid-operated switch, a valve governing the admittance of fluid pressure to operate said switch, a rod arranged to have both a longitudinal and a rotating movement and to operate said valve by both of said movements, and means for moving said rod longitudinally in response to variations of pressure in the reservoir, and for rotating said rod upon movements of the switch.

27. In a fluid pressure system, the combination of a fluid-operated switch, a valve governing the admittance of fluid pressure to operate said switch, and a rod arranged to have a longitudinal movement to open said valve, and a rotating movement to close it.

28. In a fluid pressure system, the combination of a reservoir, a fluidoperated switch, a valve governing the admittance of fluid pressure to operate said switch, a rod which by its longitudinal movement opens said valve and by its rotating movement closes it, and means for moving said rod longitudinally in response to variation of pressure in the reservoir and for rotating said rod by movement of the switch.

29. In a fluid pressure system, the combination of a reservoir, a pump supplying said reservoir, a motor for driving said pump, a controller for said motor, fluid actuated means for operating said controller, a valve for admitting fluid pressure to said controller-operating means, a rod having both a longitudinal and a rotating movement and arranged to operate said valve by either of said movements, means for moving said rod longitudinally in response to variation of the pressure in the reservoir, and means for rotating said rod by movement of the controller.

30. In a fluid pressure system, the combination of a reservoir, a pump supplying said reservoir, a motor for driving said pump, a controller for said motor, fluid actuated means for operating said controller, means for admitting fluid pressure to said controller-operating means, a rod so arranged that by either longitudinal or rotating movement it operates said admitting-means, and means for moving said rod longitudinally in response to variations of the pressure in the reservoir and for rotating said rod by movements of the controller.

31. In a fluid pressure system, the combination of a reservoir, a motor-driven. pump for supplying said reservoir, a controller for said motor, and a valve arranged to be opened by variations in the pressure of the fluid in the reservoir and to be closed by movements of the controller.

32. In a fluid pressure system, the combi nation of a reservoir, a motor-driven pump for supplying said reservoir, a controller for said motor, fluid-actuated means for operating said controller, and a valve for admitting fluid pressure to said c(mtroller-operating means, said valve being arranged to be opened by variations in the pressure of the fluid in the reservoir and to be closed by movements of the controller.

33. In a fluid pressure system, the combination of a reservoir, a pump connected to said reservoir, fluid-actuated means for controlling said pump and arranged always to be operated in a certain direction when fluid pressure is supplied to it, a valve for connecting said fluidactuated means to a source of fluid supply, and means for opening said valve upon either rise or fall of the pressure in the reservoir.

34. In a fluid pressure system, the combination of a reservoir, a pump connected to said reservoir, fluid-actuated means for controlling said pump, a valve for connecting said fluid-actuated means to a source of fluid supply, and means for opening said valve upon either rise or fall of the pressure in the reservoir and for closing said valve when the fluid-actuated means has performed its function.

35. In a fluid pressure system, the combination of a reservoir, a motor-driven pump connected thereto, a switch in the motor circuit, fluid-actuated means for operating said switch, and means for admitting fluid pressure to said fluid-actuated means upon variation of the pressure in said reservoir and for shutting oti said fluid pressure upon movement of the switch.

36. In a fluid pressure system, the combination of a reservoir, a motor-driven pump connected thereto, a fluid-operated switch in the motor circuit, and a valve arranged to be opened to admit fluid pressure to operate said switch upon variation in the pressure in the reservoir and to be closed by movement of the switch.

37. In a fluid pressure system, the combination of a reservoir, a motor-driven pump connected thereto, a fluidoperated switch in the motor circuit, a valve for admitting fluid pressure to operate said switch, and means for closing said valve upon a predetermined movement of the switch.

38. In a fluid pressure system, the combination of a reservoir, a fluid-operated switch, and means for admitting fluid pres sure to operate said switch in response to variation of the pressure in said reservoir and for shutting off said fluid pressure by movement of the switch.

39. In a fluid pressure system, the combination of a reservoir, a fluid operated switch, a valve for admitting pressure to actuate said switch, and means for opening said valve by a variation in the pressure in the reservoir and for closing it by a movement of the switch.

40. In a fluid pressure system, the combination of a reservoir, a fluid-operated switch always movable in the same direction, and means for admitting fluid pressure to operate said switch in response to variations of pressure in the reservoir and for shutting off said fluid pressure upon predetermined movements of the switch.

41. In a fluid pressure system, the combination of a reservoir, a motor-driven pump connected thereto, a fluid-actuated controller for said motor, and means responsive to both pressure in the reservoir and to movement of the controller for admitting fluid pressure to operate the controller upon variation of pressure in the reservoir and for shutting off said fluid pressure when the proper movement of the controller has been made.

42. In a fluid pressure system, the combination of a motor-driven pump supplying a reservoir, a controller for the motor, said controller being movable always in the same direction, and pressure-actuated means for moving said controller from its oft to its running position when the pressure in the reservoir reaches a certain limit, and for moving said controller from running to ofl' position when the pressure in the reservoir reaches another limit.

43. In a fluid pressure system, the combination of a motor-driven pump supplying a reservoir, a controller for the motor, said controller being always movable in the same direction, and fluid-operated means for operating said controller upon variation of pressure in the reservoir.

44. In a fluid pressure system, the combination of a motor-driven pump supplying a reservoir, a controller for the motor, means for operating said controller, and a single means for admitting operating power to cause the operation of said controller-operating means in the same direction upon either rise or fall of the pressure in the reservoir.

45. In a fluid pressure system, the combination of a motor-driven pump supplying a reservoir, a controller for the motor, means for operating said controller, and a single means for admitting operating power to said controller-operatin means upon either rise or fall of the pressure in the reservoir and for shutting off such power upon the desired movement of the controller.

46. In a fluid pressure system, the combination of a motor-driven pump supplying a reservoir, a controller for the motor, said controller being movable always in the same direction, means for operating said controller, and a single path through which power is admitted to the controller-operating means to move the controller from off to on position when the pressure in the reservoir reaches one of its limits and to move the controller from on to off position when the pressure in the reservoir reaches its other limit.

47. In a fluid pressure system, the combination of a motor-driven pump supplying a reservoir, a controller for the motor, said controller being movable always in the same direction, means for operating said controller, a single path through which power is admitted to the controller-operating means to move the controller from off to on position when the pressure in the reservoir reaches one of its limits and to move the controller from on to oil position when the pressure in the reservoir reaches its other limit, and means for interrupting said path when the controller reaches the desired position.

48. In combination, an electric switch, 'lluidoperated means for actuating said switch, a source of fluid pressure, valves controlling the fluid pressure for said fluid operated means, and a plurality of valve operating members, one of which is governed by movement of the fluid operated means and one by the fluid pressure of the source.

49.1n combination, an electric switch, fluidoperated means for actuating said switch, a source of fluid pressure, valves controlling the fluid pressure -for said fluid operated means, and a plurality of valve operating members, one of which is governed by movement of the fluid operated means, one by movement of the switch, one by the fluid pressure of the source.

50. In combination, an electric switch, fluid-operated means for actuating said switch, a source of fluid pressure, valves controlling the fluid pressure for said fluid operated means, and a plurality of valve operating members, one of which is governed by movement of the fluld operated means, and one by both movement of the switch and the fluid pressure of the source.

51. In a fluid pressure system, the combination of a reservoir, a pump for supplying said reservoir, a cylinder and piston governing' the operation of said pump, a valve for admitting pressure into one end. of said cylinder, and means for opening said valve upon either rise or fall of the pressure in the reservoir and for closing said valve after predetermined movements of the piston.

52. In a fluid pressure system, the combination of a motor-driven pump supplying a reservoir, a controller for the motor, means for operating said controller, and a single means for admitting operating power by the same path to said controller-operating means upon either rise or fall of the pressure in the reservoir. Y

In testimony whereof I aflix my signature, in the presence of two witnesses.

HERBERT W. CHENEY.

\Vitnesses Gno. B. SCHLEY, FRED J. KiNsnY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C.

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