US3859791A

US3859791A - Fluid operated hydraulically lapped control apparatus

Info

Publication number: US3859791A
Application number: US377330A
Authority: US
Inventors: Clifford W Allen; Paul E Olson
Original assignee: American Standard Inc
Current assignee: Bosch Rexroth Corp
Priority date: 1973-07-09
Filing date: 1973-07-09
Publication date: 1975-01-14
Anticipated expiration: 1992-01-14
Also published as: IT1036062B

Abstract

This invention relates to a pneumatically or hydraulically operated hydraulically lapped control apparatus in which a manually operated control valve device supplies a pneumatic or hydraulic fluid under pressure to the larger end of a differential-type abutment that is moved thereby to operate a spring-returned directional valve device. The operation of this device causes the supply of a hydraulic fluid under pressure from a source of supply of such fluid to a device to be operated thereby and to the smaller end of the differential-type abutment until substantially equal fluid pressure forces are obtained on the opposite ends of this abutment whereupon the spring-returned directional valve is rendered effective to cut off further flow of hydraulic fluid to the device to be operated and the smaller end of this abutment. Thus, a hydraulic fluid under pressure is obtained for operating a device and for effecting a self-lapping operation, the degree of this hydraulic pressure being variable in accordance with the ratio of the areas of the opposite ends of a differential-type abutment.

Description

ited i Allen et all.

tts Patent Jan. 14, 1975 [75] Inventors: Cliltord W. Allen; Paul E. Olson,

both of Lexington, Ky.

[73] Assignee: American-Standard Inc, New York,

[22] Filed: July 9, 1973 [21] Appl. No.1 377,330

[52] 11.5. C1 60/477, 137/65262, 303/54, 91/433 [51] Int. Cl. ..F15b 15/18 [58] Field of Search 303/54, 2, 10, 11, 13, 303/22 R, 22 A; 188/358, 151; 137/106, 652.62; 91/433; 244/78; 60/477 [56] References Cited UNITED STATES PATENTS 1,718,673 6/1929 Wettstein 91/433 2,184,793 12/1939 Clench i .i 91/433 2,354,562 7/1944 Webb 91/433 2,355,758 8/1944 Stevens i 303/54 2,396,951 3/1946 Horstmann 244/78 2,400,126 5/1946 Matthews 244/78 3,096,690 7/1963 Hayner .1 137/625.62 3,237,641 3/1966 Audemar... 91/433 3,260,273 7/1966 Hayner. 137/625.62 3,298,384 l/1967 Payne i 91/433 3,369,464 2/1968 Blattry 91/433 FOREIGN PATENTS OR APPLICATIONS Primary Examiner-Trygve M. Blix Assistant ExaminerGalen L. Barefoot Attorney, Agent, or FirmW. F. P'oore; R. W. Mclntire, Jr.

This invention relates to a pneumatically or hydraulically operated hydraulically lapped control apparatus in which a manually operated control valve device supplies a pneumatic or hydraulic fluid. under pressure to the larger end of a differential-type abutment that is moved thereby to operate a spring-returned directional valve device. The operation of this device causes the supply of ahydraulic fluid under pressure from a source of supply of such fluid to a device to be operated thereby and to the smaller end of the differential-type abutment until substantially equal fluid pressure forces are obtained on the opposite ends of this abutment whereupon the spring-returned directional valve is rendered effective to cut off further flow of hydraulic fluid to the device to be operated and the smaller end of this abutment, Thus, a hydraulic fluid under pressure is obtained for operating a device and for effecting a self-lapping operation, the degree of this hydraulic pressure being variable in accordance with the ratio of the areas of the opposite ends of a differential-type abutment.

ABSTRACT 3 Claims, 2 Drawing Figures 5/1969 Great Britain ..91/433 IOI] l I 72 I00 -97 I AIR SUPPLY 7t I 7 -2| l 2 62 7 7 I- 6 4| ,-Io7 5O 7 859 M (.1. J. 1 .L W IO A 25 65 68 T T I as do I 79 -67 93 64 6| I03 I02) I05 I 7 I04 99 4665a 49 1% I 522' 79 sea 73*;- L 7775 8| 7 7 eg 76" 86 e2 FLUID OPERATED I'IYDRAULICALLY LAPPEI) CONTROL APPARATUS BACKGROUND OF THE INVENTION Self-lapping valve devices in which fluid under pressure effects opening of a supply valve to cause the supply of the same kind of fluid for operating a device and for effecting a self-lapping operation to terminate the supply of fluid under pressure to the device are wellknown in the art. It is also well-known in the art that in order to obtain any specific pressure, the compressing apparatus required to provide a gas at the specific pressure is more complicated, occupies more space and is more expensive than that of a hydraulic pump capable of providing a liquid at the same specific pressure.

Accordingly, it is the general, purpose of the present invention to provide a manually operated apparatus for controlling operation of a hydraulically operated device in which the larger end of a differential-type abutment is supplied with a pneumatic or hydraulic fluid under pressure in response to manual operation of a suitable control valve device to cause this abutment to operate a spring-returned directional valve device that in turn effects the supply of a hydraulic fluid under pressure from a hydraulic pump to the hydraulically operated device and to the smaller end of this abutment until an equilibrium of forces is established on the abutment thereby allowing the spring-returned directional valve device to cut off flow of hydraulic fluid from the pump.

SUMMARY OF THE INVENTION According to the present invention, a pneumatically or hydraulically operated hydraulically lapped control apparatus comprises a manually controlled valve device for supplying a pneumatic or hydraulic fluid under pressure to the larger end of a differential-type abutment or piston that in turn operates a spring-returned directional valve device. This operation of the directional valve device effects the supply of a hydraulic fluid under pressure from the discharge of a hydraulic pump to a hydraulically operated device and to the smaller end of the differential-type piston until the hydraulic fluid pressure force on this smaller end of the differential-type piston substantially equals the force resulting from the supply of fluid under pressure to the larger end. Upon the attainment of this equilibrium of forces on the respective opposite ends of the differential-type piston, the spring-returned directional valve device is rendered operative to cut off further flow from the discharge of the hydraulic pump to the hydraulically operated device and the smaller end of the differential-type piston.

In the accompanying drawing:

FIG. 1 is a diagrammatic view, partly in section, of a pneumatically or hydraulically operated hydraulically lapped control apparatus for controlling the operation of a single-acting hydraulic fluid motor.

FIG. 2 is a diagrammatic view, partly in section, of a pneumatically or hydraulically operated hydraulically lapped control apparatus for controlling the operation of a double acting hydraulic fluid motor.

DESCRIPTION FIG. I

Referring to FIG. 1 of the drawing, the reference numeral 1 denotes a manually-operative self-lapping control valve device and may be, for example, the same as the control valve device shown and described in U.S. Pat. No. 2,355,758, issued Aug. 15, 1944 to Roy R. Stevens, and assigned to the assignee of the present invention.

As explained in detail in the above-mentioned United States patent, the control valve device 1 is connected to any suitable supply of a pneumatic or hydraulic fluid under pressure (not shown) by a pipe 2 and may be se lectively manually-operated accordingly as a handle 3 is rocked in one direction or in an opposite direction to vary the pressure of fluid in either of two pipes while maintaining the other pipe open to atmosphere. In the first embodiment of the invention only one of these pipes is used and is denoted by the: numeral 4. It should be understood that the supply port (not shown) to the other of the two pipes is closed by any suitable means.

As shown in FIG. 1, a pneumatic or hydraulic pressure actuated power piston 5 is slidably mounted in a first counterbore 6 that is coaxial with a second counterbore 7 and a bore 8 formed in a casing 9. The open end of the counterbore 6 is closed by a pressure head 10 that is secured to the casing 9 by any suitable means (not shown).

The piston 5 cooperates with the casing 9 and the pressure head 10 to form on the respective opposite sides of this piston a pair of chambers I1 and 12. Opening into the chamber 11 is a port 13 to which one end of the hereinbefore-mentioned pipe 4 is connected in order that a pneumatic or hydraulic pressure may be established in this chamber II in response to manual rocking of the handle 3 of the control valve device I from its neutral position in which it is shown in FIG. 1 in the direction to cause the supply of a pneumatic or hydraulic fluid under pressure from the supply pipe 2 to the pipe 4. The chamber 12 shown in FIG. 1 is open to atmosphere via a port 14.

As shown in FIG. 1, a hydraulic piston 15 at one end is formed integral with the pneumatic or hydraulic pressure actuated piston 5 and is slidably mounted in the counterbore 7 in the casing 9. The other end ofthe hydraulic piston 15 has formed integral therewith a valve operating stem 16 that extends through the bore 8 in the casing 9 to the exterior thereof for effecting the operation of a three-way three'position directional valve device 17 of any commercially available type in a manner hereinafter described.

The piston 5 is provided with a peripheral annular groove in which is disposed an O-ring seal 18 to prevent leakage of fluid under pressure from the chamber ll along the interior wall surface of the counterbore 6 to the chamber 12 which is open to atmosphere via port 14.

Likewise, the piston 15 is provided adjacent its righthand end with a peripheral annular groove in which is disposed an O-ring seal 19 to prevent leakage of hydraulic fluid under pressure from the interior of counterbore 7 on the right-hand side of this piston 15 along the interior wall surface of the bore 7 to the chamber 12 which is open to atmosphere, as aforestated.

Furthermore, the wall surface of the bore 8 is provided with an annular groove in which is disposed an O-ring seal 20 to prevent leakage of hydraulic fluid under pressure from the interior ofcounterbore 7 along the interior wall surface of the bore 8 to atmosphere.

For controlling the supply of hydraulic fluid under pressure from a pipe 21 connected to the discharge port of a constant output hydraulic pump 22 to a singleacting hydraulic fluid motor 23, the hereinbeforementioned directional valve device 17 is arranged so that an operating stem 24 thereof is coaxial with and rigidly connected by any suitable means to the valve operating stem 16 that is integral with the piston 15. Upon movement of the

operating stems

16 and 24 in the direction of the right hand from the position in which they are shown in FIG. 1 of the drawing in a manner hereinafter described, the valve device 17 is moved against the yielding resistance of a spring 25 to a supply position denoted in FIG. 1 of the drawing by the numeral 26 in which the pipe 21 connected to the discharge outlet of the hydraulic pump 22 is connected through the valve device 17 to one end of a pipe 27 the opposite end of which opens into a chamber 28 formed in the fluid motor 23 between a piston 29 and a pressure head 30 secured by any suitable means (not shown) to the open end of a cup-shaped fluid motor casing 31 having a bore 32 and a coaxial counterbore 33 in which the piston 29 is slidably and sealably mounted.

Formed integral at one end with the piston 29 is a piston rod 34 that extends through the bore 32 in the easing 31 to the exterior thereof for connection to a device (not shown), such as, for example, the arm of a back hoe excavating device to be operated by the fluid motor 23.

Connected to the pipe 27 intermediate the ends thereof is one end of a pipe 36 the opposite end of which is connected by a correspondingly numbered passageway to a chamber 37 formed between the righthand end of the hydraulic piston 15 and the right-hand end of the counterbore 7 in the casing 9.

Connected to the pipe 36 intermediate the ends thereof is one end of a short pipe 38 that at its opposite end is connected to a pressure gage 39 having an indicating hand 40 for indicating to an observer the pressure of the hydraulic fluid present in the

pipes

27 and 36 and the

chambers

28 and 37.

While the handle 3 of the control valve device 1 occupies its neutral position shown in FIG. 1, the chamber 11 at the left-hand side of the power piston is open to atmosphere via the pipe 4 and this valve device 1 in the manner explained in hereinbefore-mentioned US. Pat. No. 2,355,758, and the chamber 12 at the right-hand side of this piston 5 is open to atmosphere via the port 14.

With equal pressures present in the chambers 11 and 12 on the respective opposite sides of power piston 5, the hereinbefore-mentioned spring 25 and a second spring 41 are cooperatively effective to bias the pistons 5 and to the position in which they are shown in FIG. 1 and the directional valve device 17 to a center or lap position in which it is shown in the drawing and denoted by the numeral 42. In this position the pipe 27 is cut off from the pipe 21 and also form one end of a pipe 43 that at its opposite end opens into a sump 44 to which the inlet port of pump 22 is connected by a pipe 44a.

OPERATION FIG. 1

Let it be assumed that the handle 3 of the manually operative self-lapping control valve device 1 occupies its neutral position in which it is shown in FIG. 1. Consequently, the chambers 11 and 12 at the respective opposite sides of the power piston 5 will be subject to equal pressure in the manner hereinbefore explained, and the

springs

25 and 41 will bias the

pistons

5 and 15 to the position shown in FIG. 1 and the directional valve device 17 to its center or lap position in which it is shown and indicated by the reference numeral 42.

Let it be further assumed that

pipes

27 and 36 and

chambers

28 and 37 are void of hydraulic fluid under pressure.

Furthermore, let it be assumed that the hydraulic pump 22 is being driven by any suitable means (not shown) so that the pipe 21 is charged with a suitable hydraulic fluid under pressure.

If now an operator desires that a chosen degree of hydraulic fluid under pressure be established in the chamber 28 to move the piston 29 of the single-acting hydraulic fluid motor 23 in the direction of the right hand to move, for example, the arm of the back hoe to a desired position, he will rock the handle 3 of the manually operative self-lapping valve device 1 from its neutral position in which it is shown in FIG. 1 in the direction to cause this self-lapping control valve device 1 to operate in the manner described in detail in hereinbeforementioned U.S. Pat. No. 2,355,758 to effect the supply of either a pneumatic or hydraulic fluid under pressure from the supply pipe 2 to the pipe 4 and the chamber 11 at the left-hand side of the piston 5 to cause an increase of pressure in this pipe 4 and chamber 11, it being understood that the degree of pressure established in the chamber 11 corresponds to the amount of arcuate movement of the handle 3 from its neutral position.

As fluid under pressure is supplied to the chamber 1 I by manual operation of the control valve I in the manner described above, the pressure of the fluid in this chamber 11 will be increased to the degree corresponding to the position to which the handle 3 is rocked by the operator.

It may be seen from FIG. 1 of the drawing that as the pressure in the chamber 11 increases, it is effective to move the

pistons

5 and 15 and stems 16 and 24 in the direction of the right hand, viewed in FIG. 1, to shift the directional valve device 17 against the yielding resistance of the spring 25 from the position in which it is shown and denoted by the reference numeral 42 to the position denoted by the reference numeral 26.

When the directional valve device 17 is shifted to the position denoted by the numeral 26 in FIG. 1, a communication is established between the

pipes

21 and 27 via this valve device 17.

Upon the establishment of a communication between the

pipes

21 and 27 in the manner just explained, the hydraulic fluid under pressure discharged by the hydraulic pump 22 to the pipe 21 will flow therefrom to the chamber 28 at the left-hand face of the piston 29 of the hydraulic fluid motor 23 via the directional valve device 17, now in the position denoted by the reference numeral 26, and the pipe 27.

It will be noted from FIG. 1 that some of the hydraulic fluid under pressure supplied to the pipe 27 will flow therefrom to the chamber 37 at the right-hand side of the hydraulic piston 15 via the pipe and passageway 36.

Furthermore, some of the hydraulic fluid under pressure supplied to the pipe 36 will flow to the gage 39 via the pipe 38 in order that the indicating hand 40 of this gage will indicate to the operator the pressure in the

chambers

28 and 37, this pressure being an indication of the position of piston 29.

Hydraulic fluid under pressure will flow from the discharge of the hydraulic pump 22 to the chamber 28 to increase the pressure therein. As the pressure of the hydraulic fluid in the chamber 28 increases, it becomes effective to move the piston 29 in the direction of the right hand, as viewed in FIG. 1. This movement of the piston 29 is effective via the piston rod 34 to operate the device, such as, for example, the arm of a back hoe connected to the exterior end of this rod.

Likewise, hydraulic fluid under pressure will flow from the discharge of the hydraulic pump 22 to the chamber 37 to cause an increase in the pressure of the hydraulic fluid in this chamber.

The hydraulic fluid under pressure supplied to the chamber 37 acts in a left-hand direction on an area equal to the area of the hydraulic piston less the area of the operating stem 16. Accordingly, when the hydraulic fluid pressure force acting in a left-hand direction on this area substantially balances the pneumatic or hydraulic fluid pressure force acting in a right-hand direction on the left-hand face of piston 5, the spring will be rendered effective to move the stems 24 and 16,

pistons

15 and 5, and the directional valve device 17 in the direction of the left hand, as viewed in FIG. 1, so that the directional valve 17 is moved from its supply position denoted in FIG. 1 of the drawing by the reference numeral 26 back to its center or lap position denoted by the reference numeral 42 to cut off flow of hydraulic fluid under pressure from the discharge of the hydraulic pump 22 to the chamber 28 in the single acting hydraulic fluid motor 23 and the chamber 37 at the right-hand end of the hydraulic piston 15. From the foregoing, it is apparent that the hydraulic pressure supplied to the

pressure chambers

28 and 37 is greater than the pneumatic or hydraulic pressure supplied to the chamber 11 by an amount in accordance with the difference in the area of the larger piston 5 and the smaller area equal to the area of the piston 15 less the area of the stem 16.

Since it is well-known that, in order to obtain any given specific pressure, the compressing apparatus re quired to provide a gas at the specific pressure is more complicated and costly, and also occupies more space, than that of a hydraulic pump capable of discharging a hydraulic fluid at the same specific pressure, the advantage of applicants self-lapping apparatus shown in FIG. 1 of the drawings and utilizing the hydraulic fluid under pressure discharged by the pump 22 for effecting both the self-lapping operation of this apparatus and also the operation of the single-acting fluid motor 23 is readily apparent.

Should the operator now desire that a nydraulic pressure be established in the chamber 28 of the hydraulic fluid motor 23 that is in excess of the hereinbeforementioned chosen degree to effect movement of the piston 29 further in the direction of the right hand, as viewed in FIG. 1, he will rock the handle 3 of the manually-operative self-lapping valve device 1 from the position that it occupies further in the direction to cause this valve device 1 to effect the supply of fluid under pressure from the supply pipe 2 to the pipe 4 and chamber 11 to cause a further increase of the pressure in this chamber.

As the pressure in the chamber 11 is increased in response to the supply offluid under pressure thereto, the

pistons

5 and 15 and stems 16 and 24 will operate the directional valve device 17 in the manner hereinbefore explained to establish a communication between the

pipes

21 and 27 whereupon hydraulic fluid under pressure will be supplied from the discharge of the pump 22 to the

chambers

28 and 37.

This supply of hydraulic fluid under pressure to the chamber 28 is effective to move piston 29 and piston rod 34 in the direction of the right hand against the resistance offered by the weight of the arm of the back hoe until the force of gravity due to this weight and the hydraulic fluid pressure force acting on the respective opposite sides of the piston 29 are equal in magnitude and opposite in direction.

The hydraulic fluid under pressure supplied to the chamber 37 will increase the pressure therein until the hydraulic fluid pressure force acting on hydraulic pis ton 15 and the pneumatic or hydraulic fluid pressure force acting on the piston 5 are substantially equal and opposite in direction, whereupon the spring 25 is rendered effective to cause the directional valve 17 to return to its lap or center position and cut off further flow of hydraulic fluid under pressure to the

chambers

28 and 37.

If the operator now desires to reduce the pressure of the hydraulic fluid in the chamber 28 of the hydraulic fluid motor 23 to cause the weight of the arm of the back hoe to move the piston 29 and piston rod 34 in the direction of the left hand, as viewed in FIG. 1, he will rock the handle 3 of the manually operative valve device 1 from the position it occupies toward the position in which it is shown. This rocking of the handle 3 operates the control valve device 1 in the manner explained in hereinbefore-mentioned US. Pat. No. 2,355,758 to release the fluid under pressure present in the chamber 11 and pipe 4 to atmosphere or a sump (not shown) so that the pressure in chamber 11 and pipe 4 is reduced to a degree determined by the position to which the handle 3 is rocked.

As the pressure in the chamber 11 is reduced in the manner just explained, the hydraulic fluid under pressure present in the chamber 37 is rendered effective to shift the

pistons

5 and 15, stems 16 and 24, and the directional valve device 17 in the direction of the left hand, as viewed in FIG. 1, against the yielding resistance of the spring 41 from the central or lap position in which it is shown in FIG. 1 and denoted by the reference numeral 42 to a release position denoted by the reference numeral 45.

When the directional valve device 17 is thus shifted to its release position denoted by the reference numeral 45, a communication is established between the pipes 27 and 43 via this valve device.

Consequently, upon the establishment of a communication between the pipes 27 and 43, the hydraulic fluid under pressure in the chamber 28 of the hydraulic fluid motor 23 will flow to the sump 44 via pipes 27 and 43 and the valve device 17 now in its release position to effect a reduction of the pressure in chamber 28.

Likewise, hydraulic fluid under pressure present in the chamber 37 will flow to the sump 44 via

pipes

36, 27 and 43 and the valve device 17 to effect a corresponding reduction of the pressure in chamber 37.

As the pressure of the hydraulic fluid in the chamber 37 is reduced, the hydraulic fluid pressure force acting in the direction of the left hand, as viewed in FIG. 1, on the difference in the area of the hydraulic piston 15 and the stem 16 is correspondingly reduced. Consequently, it is apparent that as the pressure of the hydraulic fluid in the chamber 37 is reduced, the spring 41 is rendered effective to shift the directional valve device 17 in the direction of the right hand, as viewed in FIG. 1, from its release position denoted by the reference numeral to its lap or central position in which it is shown and denoted by the reference numeral 42 to cut off further flow of hydraulic fluid under pressure from the

chambers

37 and 28 to the sump 44.

From the foregoing, it is apparent that as the pneumatic or hydraulic pressure in the chamber 11 is reduced in response to manual rocking of the handle 3 of the control valve device 1 toward the position in which it is shown in FIG. 1 to effect a reduction of the pneumatic or hydraulic pressure in the chamber 11 and therefore, a reduction of the fluid pressure force acting in a righthand direction on the piston 5, the directional valve device 17 is operated in response to the reduction of this fluid pressure force to effect a corresponding reduction of the hydraulic fluid pressure in the

chambers

37 and 28 thereby causing a corresponding reduction of the hydraulic fluid pressure force acting on the pistons l5 and 29.

As the pressure of the hydraulic fluid in the chamber 28 of the hydraulic fluid motor 23 is reduced, the

weight of the arm of the back hoe is rendered effective to shift the piston 29 and piston rod 34 in the direction of the left hand, as viewed in FIG. 1, until the reduced hydraulic fluid pressure force and the force of gravity due to this weight acting on the respective opposite sides of the piston 29 are equal in magnitude and opposite in direction.

In view of the description and operation given above for the apparatus shown in FIG. 1 of the drawing, it is apparent that this apparatus constitutes a pneumatically or hydraulically controlled hydraulically operated self-lapping mechanism for controlling the operation of the single-acting hydraulic fluid motor 23, it being noted that the constant output hydraulic pump 22 emv bodied in this mechanism is smaller, less expensive, and

more compact than an air compressor capable of the same performance.

DESCRIPTION FIG. 2

According to a second embodiment of the invention, the manually operative self-lapping control valve device l of the first embodiment has its supply pipe 2 connected to any suitable supply of pneumatic or hydraulic fluid under pressure (not shown). According to this second embodiment of the invention, a pneumatic or hydraulic power piston 46 shown in FIG. 2 differs from the pneumatic or hydraulic power piston 5 shown in FIG. 1 in that fluid under pressure may be supplied to the respective opposite faces thereof by manual operation of the control valve device 1, and the single-acting hydraulic fluid motor 23 shown in FIG. 1 is replaced by a double-acting hydraulic fluid motor 47. Accordingly, like reference numerals have been used to designate the structure shown in FIG. 2 which is identical to that shown in FIG. 1. Only such features of the structure and operation of the embodiment of the invention shown in FIG. 2 which differ from that of the embodiment of FIG. 1 will be hereinafter described.

As shown in FIG. 2, the pneumatic or hydraulic power piston 46 is slidably mounted in a first counterbore 48 that extends inward from the left-hand end of a casing section 49 and is coaxial with a bore 50 formed in this casing section. The open end of the counterbore 48 is closed by the pressure head 10 that is secured to the casing section 49 by any suitable means (not shown).

The piston 46 cooperates with the casing section 49 and the pressure head 10 to form on the respective opposite sides of this piston a pair of

chambers

51 and 52. Opening into the chamber 51 is a port 53 to which is connected one end of a pipe 54 the opposite end of which is connected to the control valve device 1, it being understood that this pipe 54 constitutes the other one of the two pipes in which the pressure of a fluid may be varied by operation of this control valve device 1 in the manner described in hereinbefore-mentioned US. Pat. No. 2,355,758. The one of these two pipes shown in FIG. 1 and denoted by the numeral 4 is connected to a port 55 that opens into the chamber 52 at the right-hand side of the pneumatic or hydraulic power piston 46.

As shown in FIG. 2, a piston rod 56, threaded at one end and formed integral at its opposite end with the power piston 46, extends through the bore 50 and into a counterbore 57 that is coaxial therewith and formed in a cylindrical boss 58 that is integral with the casing section 49.

The screw-threaded end of the piston rod 56, as shown in FIG. 2, has screw-threaded engagement with a hydraulic piston 59 that is slidably mounted in the counterbore 57. Formed integral with the right-hand side of this hydraulic piston 59 is a valve operating stem 60 that extends through a bore 61 provided in a pressure head 62 that is secured to the open end of the counterbore 57 by any suitable means (not shown).

The pneumatic or hydraulic power piston 46 and the hydraulic piston 59 are each provided with a peripheral annular groove in which are respectively disposed O-

ring seals

63 and 64 that form a seal with the wall surface of the respective counterbores 48 and 57 to prevent leakage of fluid under pressure from either side of the respective piston to the other side.

The wall of the bore 50 is provided with an annular groove in which is disposed an O-ring seal 65 that forms a seal with the peripheral surface of the piston rod 56 to prevent leakage of fluid under pressure from either of the counterbores 48 and 57 to the other.

Likewise, the wall of the bore 61 is provided with an annular groove in which is disposed an O-ring seal 66 that forms a seal with the peripheral surface of the valve operating stem 60 to prevent leakage of fluid under pressure from that portion of the counterbore 57 on the right-hand side of the piston 59 to atmosphere.

For controlling the supply of hydraulic fluid under pressure from the pipe 21 that is connected to the discharge port of the constant output hydraulic pump 22 to the double-acting hydraulic fluid motor 47, a threeposition directional valve device 67 is so arranged that an operating stem 68 thereof is coaxial with the valve stem 60. These two stems 60 and 68 are rigidly secured together by any suitable means (not shown) to enable operation of the valve device 67 in response to shifting of the pistons 46 and 59 in one direction or in an opposite direction.

While the directional valve device 67 occupies its center position in which it is shown in FIG. 2 and denoted by the reference numeral 69, the pipe 21 is connected to one end of a pipe 70 the opposite end of which opens into the sump 44. As shown in FIG. 2, the inlet of the pump 22 is connected by the pipe 44a to the pipe intermediate the ends thereof. Consequently, while the directional valve 67 occupies the position shown, operation of the pump 22 circulates hydraulic fluid through the pipes 44a and 70 without building up a pressure greater than that required to overcome the frictional resistance to flow of fluid through these pipes.

Upon movement of the operating stems 60 and 68 in the direction of the right hand, as viewed in FIG. 2, from the position in which they are shown, in a manner hereinafter described, the valve device 67 is moved, against the yielding resistance of the spring 25, from its center position indicated by the reference numeral 69 to the position denoted in FIG. 2 by the reference numeral 71 in which one end of a pipe 72 is connected through the valve device 67 to a pipe 73 that opens into a chamber 74 formed in the hydraulic fluid motor 47 between the left-hand face of a piston 75 and a first pressure head 76 secured by any suitable means (not shown) to the left-hand open end of a hollow cylindrical fluid motor casing 77 in which the piston 75 is slidably and scalable mounted. The opposite end of the pipe 72 is connected to the pipe 21 intermediate the ends thereof and a one-way or check valve device 78 is so disposed in the pipe 72 intermediate the ends thereof so as to provide for flow of hydraulic fluid under pressure from the pipe 21 to the pipe 73 while the directional valve device 67 occupies the position denoted by the reference numeral 71 and prevent flow in the opposite direction.

Furthermore, while the directional valve device 67 occupies the position denoted by the reference numeral 71, one end of a pipe 79 is connected through this valve device 67 to one end of a pipe 80. The opposite end of the pipe 79 opens into a chamber 81 formed in the hydraulic fluid motor 47 between the right-hand face of the piston 75 and a second pressure head 82 secured by any suitable means (not shown) to the righthand end of casing 77. The opposite end of the pipe is connected to the pipe 44a intermediate the ends thereof.

A piston rod 85 that at one end is integral with the piston 75 extends through a bore 86 provided therefor in the pressure head 82 to the exterior of the hydraulic fluid motor 47 and may be connected to a device (not shown) to be operated by this double-acting hydraulic fluid motor in either direction from any position between two end positions.

Connected to the pipe 73 intermediate its ends is one end ofa pipe 87 the opposite end of which is connected by a corresponding passageway in the pressure head 62 to a chamber 88 formed between this pressure head and the right-hand face of the hereinbefore-mentioned hydraulic piston 59.

A short pipe 89 connects a first gage 90 to the pipe 87 intermediate the ends thereof. This gage 90 has an indicating hand 91 for indicating to an observer or an operator the pressure of the hydraulic fluid present in the

pipes

73 and 87 and the chambers 74 and 88.

Connected to the pipe 79 intermediate its ends is one end of a pipe 92 the opposite end of which is connected by a corresponding passageway in the casing section 49 to a chamber 93 formed between the left-hand face of the hydraulic piston 59 and the left-hand end of the counterbore 57. I

A second gage 94 is connected to the pipe 92 by a short pipe 95 and is provided with an indicating hand 96 for indicating to an observer the pressure of the hydraulic fluid present in the

pipes

79 and 92 and the

chambers

81 and 93.

The control apparatus shown in FIG. 2 is provided with three fluid pressure operated limiting

valve devices

97, 98 and 99 each ofwhich has an abutment (not shown) that, in response to the supply of fluid under pressure to a chamber (not shown) at one side of this abutment until the pressure in this chamber exceeds a chosen value, operates a valve mechanism to establish a fluid pressure communication therethrough.

The limiting valve device 97 is disposed in a pipe 100 that at one end is connected to the pipe 21 adjacent the discharge port of the pump 22 and at the opposite end is connected to the pipe 44a intermediate the ends thereof. The chamber at the one side of the abutment of this limiting valve device 97 is connected by a pipe 101 to that portion of the pipe 100 that extends between the pipe 21 and this limiting valve device 97. Therefore, this limiting valve device 97 is operative in response to the pump discharge pressure in the pipe 21 exceeding a chosen value to establish a communication through which the hydraulic fluid under pressure discharged from the pump 22 to the pipe 21 may be returned to the sump 44 via the pipes 100 and 44a. Accordingly, valve device 97 operates to limit pump discharge pressure.

The limiting valve device 98 is disposed in a pipe 102 that at one end is connected to the pipe 73 intermediate the ends thereof and at the opposite end is connected to the pipe 70 intermediate the ends of this pipe. The chamber at the one side of the abutment of this limiting valve device 98 is connected by a pipe 103 to that portion of the pipe 102 that extends between the pipe 73 and this limiting valve device 98. Therefore, this limiting valve device 98 is operative in response to the pressure of the hydraulic fluidl in the

pipes

73 and 87 and chambers 74 and 88 exceeding a chosen value to establish a communication through which hydraulic fluid under pressure in the

pipes

73 and 87 and chambers 74 and 88 may be returned to the sump 44 via the

pipes

102 and 70. Therefore, it is seen that limiting valve device 98 operates to limit the pressure that may be obtained in chambers 74 and 88.

The limiting valve 99 is disposed in a pipe 104 that at one end is connected to the pipe 79 and at the opposite end is connected to the pipe 44a intermediate the ends thereof. The chamber at the one side of the abutment of this limiting valve device '99 is connected by a pipe 105 to that portion of the pipe 104 that extends between the pipe 79 and this limiting valve device 99. Accordingly, it is apparent from the foregoing that this limiting valve device 99 is operative to limit the pres' sure of the hydraulic fluid in the

chambers

81 and 93.

OPERATION FIG. 2

Let it be assumed that the handle 3 of the manually operative self-lapping control device 1 occupies its neutral position in which it is shown in FIG. 2. Consequently, no pressure is present in the

chambers

51 and 52 and the

springs

25 and 41 will bias the pistons 46 and 59 to the position shown in FIG. 2 and the directional valve device 67 to its center or lap position in which it is shown and indicated by the reference numeral 69.

Let it be further assumed that the piston 75 and the piston rod 85 occupy the position in which they are shown.

Furthermore, let it be assumed that the hydraulic pump 22 is being driven to circulate a hydraulic fluid through the

pipes

21, 70 and 44a and the directional valve device 67.

Assume now that the operator desires that a chosen degree of hydraulic fluid under pressure be established in the chamber 74 to move the piston 75 and piston rod 85 of the double-acting hydraulic fluid motor 47 in the direction of the right hand against the resistance of the device connected to the piston rod 85 until the resisting force of this device and the fluid pressure force resulting from the establishment of the chosen degree of hydraulic pressure in the chamber 74 acting on the lefthand face of the piston 75 are equal and opposite. Accordingly, the operator will rock the handle 3 of the valve device 1 from its neutral position in which it is shown in FIG. 2 in the direction to cause the establishment ofa pneumatic or hydraulic pressure in the chamber 51 in the manner hereinbefore described for the first embodiment of the invention to a degree corresponding to the amount of counterclockwise rocking of handle 3 out of its neutral position.

As the pneumatic or hydraulic pressure in the chamber 51 increases, it is effective to move the pistons 46 and 59, piston rod 56, and valve operating stems 60 and 68 in the direction of the right hand, as viewed in FIG. 2, to shift the directional valve device 67 against the yielding resistance of the spring from the position denoted by the reference numeral 69 to the position denoted by the reference numeral 71.

When the directional valve device 67 is shifted to the position denoted by the reference numeral 71, (1) the communication between the

pipes

21 and 70 is closed, (2) a supply communication is established between the

pipes

72 and 73, and (3) a release communication is established between the

pipes

79 and 80.

Upon the establishment of the communication between the

pipes

72 and 73, the hydraulic fluid under pressure discharged by the pump 22 to the pipe 21 will flow therefrom to (l) the chamber 74 at the left-hand side of the piston 75 via pipe 72, check valve 78, directional valve device 67 now in the position indicated by the numeral 71, and pipe 73, and (2) the chamber 88 at the right-hand side of the piston 59 via pipe 72, check valve 78, valve device 67, and

pipes

73 and 87.

As the pressure in the chamber 74 increases, it becomes effective to move the piston 75 and piston rod 85 in the direction of the right hand, as viewed in FIG. 2, and cause the flow of hydraulic fluid from the chamber 81 to the sump 44 via

pipes

79, 80 and 44a and valve device 67. This movement of the piston rod 85 is effective to operate the device connected thereto.

The hydraulic fluid under pressure supplied to chamber 88 acts in the direction of the left hand on an area equal to the difference in the area of the piston 59 and the stem 60. Accordingly, upon the pressure in the chamber 88 increasing sufficiently to establish a hy draulic fluid pressure force acting in a left-hand direction that substantially balances the pneumatic or hydraulic fluid pressure force acting in a right-hand direc tion on the left-hand face of the piston 46, the spring 25 will be rendered effective to return the pistons 46 and 59 and the directional valve device 67 to the position shown inFlG. 2 to cut off flow of hydraulic fluid under pressure to the chambers 74 and 88.

Should the operator now desire to further increase the pressure in the chambers 74 and 88, he will rock the handle 3 counterclockwise from the position it occupies to a position corresponding to the pressure desired in these chambers. The valve device 1, pistons 46 and 59 and the directional valve device 67 will then be operated in the manner hereinbefore described to cause an increase in the pressure of the hydraulic fluid in the chambers 74 and 88 to a degree corresponding to the position to which the handle 3 is moved.

The pressure in the chambers 74 and 88 can thus be increased up to a maximum pressure upon moving the handle 3 to the position indicated in FIG. 2 by the reference numeral 106.

Let it be supposed that the operator now desires to effect movement of the piston and piston rod from the position they occupy in the direction of the left hand to another position. To effect this movement, the operator will rock the handle 3 of the manually operative control valve device 1 clockwise from the position it occupies toward the position in which it is shown in FIG. 2 to a position corresponding to the position to which it is desired that the piston 75 and piston rod 85 be moved.

This clockwise rocking of the handle 3 causes the control valve device 1 to effect a corresponding reduction of the pneumatic or hydraulic pressure in the chamber 51. As the pneumatic or hydraulic pressure in the chamber 51 is thus reduced, the hydraulic fluid under pressure present in the chamber 88 is rendered effective to shift the pistons 46 and 59, piston rod 56, valve operating stem 60 and the directional valve device 67 in the direction of the left hand, as viewed in FIG. 2, against the yielding resistance of the spring 41 from the central position of the valve device 67 denoted by the reference numeral 69 to a third position of this valve device 67 denoted in FIG. 2 by the reference numeral 107.

When the directional valve device 67 is thus shifted to the position denoted by the numeral 107, (l) a supply communication is established between

pipes

72 and 79, and (2) a release communication is established between the

pipes

73 and 80.

Upon the establishment of the communication between

pipes

72 and 79, hydraulic fluid under pressure discharged by the pump 22 to the pipe 21 will flow therefrom to (l) the chamber 81 at the right-hand side of the hydraulic piston 75 via pipe 72, check valve 78, valve device 67 now in the position denoted by the numeral 107 and pipe 79, and (2) the chamber 93 via the pipe 92 which is connected to the pipe 79.

Upon the establishment of the communication between the

pipes

73 and 80, hydraulic fluid under pressure in the chamber 74 at the left-hand side of the piston 75 will flow to the sump 44 via pipe 73, valve device 67, and

pipes

80, 44a and 70. Simultaneously, hydraulic fluid under pressure will be released from the chamber 88 to the sump 44 since this chamber 88 is connected to the pipe 73 by the pipe 87.

Hydraulic fluid under pressure will now flow simultaneously from the discharge of the pump 22 to the chamber 93 and from the chamber 88 to the sump 44 until the resulting differential hydraulic fluid pressure force acting on the hydraulic piston 59 is substantially equal in magnitude and opposite in direction to the reduced pneumatic or hydraulic fluid pressure force acting on the piston 46 whereupon the spring 41 is rendered effective to shift the directional valve device 67 from the position denoted by the reference numeral 107 back to the neutral position denoted by the reference numeral 69 to thereby cut off the flow of hydraulic fluid under pressure from the pump 22 to the

chambers

81 and 93 and the release of hydraulic fluid under pressure from the chambers 74 and 88 to the sump 44.

As hydraulic fluid under pressure is simultaneously released from the chamber 74 and supplied to the chamber 81 in the hydraulic fluid motor 47 in the manner explained above, the piston 75 and the piston rod 85 will be moved in the direction of the left hand, as viewed in FIG. 1, to operate the device connected to rod 85 until an equilibrium of forces is established on the opposite sides of this piston 75.

From the foregoing, it is apparent that upon return of the handle 3 of the valve device 1 to the position shown in FIG. 2, the piston 75 and piston rod 85 will be returned to a corresponding position.

If the handle 3 of the valve device I be now rocked in a clockwise direction from the position shown toward or to the handle position denoted in FIG. 2 by the reference numeral 108, a pneumatic or hydraulic pressure will be established in the chamber 52 that corresponds to the new position of the handle 3.

It is apparent from the foregoing that for the establishment of any degree of pneumatic or hydraulic pressure in the chamber 52, the directional valve device 67 will be operated to effect the release of hydraulic fluid under pressure from the chamber 74 to the sump 44 and the supply of hydraulic fluid under pressure to the chamber 81 to cause the piston 75 and piston rod 85 to be shifted from the position they occupy, in the direction of the left hand, as viewed in FIG. 1, to a position corresponding to the above-mentioned new position of the handle 3. Furthermore, it is apparent that if the handle 3 is now rocked counterclockwise toward or to the position shown in FIG. 2, the directional valve device 67 will be operated to cause the piston 75 and piston rod 85 to be shifted in the direction of the right hand, as viewed in FIG. 1, toward or to a corresponding position.

From the foregoing, it is apparent that the present invention constitutes a self-lapping valve mechanism operable by a pneumatic or hydraulic fluid under pressure under the control of an operator to effect the supply of a hydraulic fluid under pressure from the discharge of a hydraulic pump to cause the operation of either a single-acting or double-acting hydraulic fluid motor and the self-lapping operation of the valve mechanism to cut off flow from the pump to the respective motor.

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

1. In a controlling apparatus for fluid pressure equipment, the combination of:

a. a constant output hydraulic pump for supplying hydraulic fluid under pressure, wherein the improvement comprises:

b. a one-way flow valve means,

c. a double-acting hydraulic fluid motor provided with a piston having on each side thereof a chamber to which hydraulic fluid under pressure may be supplied,

d. a sump,

a threeposition valve means having a first hydraulic supply port to which said pump supplies hydraulic fluid under pressure via said one-way flow means, a second supply port to which said pump simulta neously supplies hydraulic fluid under pressure in bypassing relation to said one-way flow means, a pair of hydraulic delivery ports to enable said valve means to respectively in one and another of its positions effect the supply of hydraulic fluid under pressure from said pump to the respective chamber at each side of said piston of said fluid motor, and a pair of release ports connected to said sump, one of which in said one and another positions selectively connects the respective chamber at one side of said piston of said fluid motor to said sump to release hydraulic fluid under pressure from one of said chambers to said sump simultaneously as hydraulic fluid under pressure is supplied to the other of said chambers from said pump via one of said delivery ports, and the other of which release ports, in the third one of said positions, establishes a com munication through which hydraulic fluid under pressure supplied by said pump to said second supply port is released to said sump to enable operation of said hydraulic pump under minimum load while said valve means occupies said third one of said positions,

f. differential-type abutment means having two abutments the area of the respective sides of one of which is less than the area of the respective sides of the other, and said abutment means being rigidly connected to said valve means for controlling the operation thereof to establish said communications, the respective sides of said one abutment being constantly connected to said delivery ports and selectively subject to the pressure in one of said delivery ports or in one of said release ports, and

g. means for effecting variations of a pneumatic or hydraulic fluid pressure force on the respective opposite sides of the other of said two abutments to cause the operation of said valve means from said third position respectively to said one and another position so long as said pneumatic or hydraulic fluid pressure force on one of said respective opposite sides of said other abutment exceeds the hydraulic fluid pressure force on that side of said smaller abutment opposite said one side of said other abutment, and the operation of said valve means from either said one or said another position to said third position upon the reduction of the pneumatic or hydraulic fluid pressure force acting in one direction on said larger abutment to a value less than the hydraulic fluid pressure force acting in an opposite direction on said smaller abutment.

2. In a controlling apparatus for fluid pressure equipment, as recited in claim 1, further characterized by biasing means effective to maintain said valve means in said third position upon loss of pneumatic or hydraulic fluid pressure on either of the opposite sides of said other abutment.

3. In a controlling apparatus for fluid pressure equipment, as recited in claim 1, further characterized by conduit means to enable minimum load operation of said pump independently of said sump.

* i I i =i

Claims

1. In a controlling apparatus for fluid pressure equipment, the combination of: a. a constant output hydraulic pump for supplying hydraulic fluid under pressure, wherein the improvement comprises: b. a one-way flow valve means, c. a double-acting hydraulic fluid motor provided with a piston having on each side thereof a chamber to which hydraulic fluid under pressure may be supplied, d. a sump, a three-position valve means having a first hydraulic supply port to which said pump supplies hydraulic fluid under pressure via said one-way flow means, a second supply port to which said pump simultaneously supplies hydraulic fluid under pressure in bypassing relation to said one-way flow means, a pair of hydraulic delivery ports to enable said valve means to respectively in one and another of its positions effect the supply of hydraulic fluid under pressure from said pump to the respective chamber at each side of said piston of said fluid motor, and a pair of release ports connected to said sump, one of which in said one and another positions selectively connects the respective chamber at one side of said piston of said fluid motor to said sump to release hydraulic fluid under pressure from one of said chambers to said sump simultaneously as hydraulic fluid under pressure is supplied to the other of said chambers from said pump via one of said delivery ports, and the other of which release ports, in the third one of said positions, establishes a communication through which hydraulic fluid under pressure supplied by said pump to said second supply port is released to said sump to enable operation of said hydraulic pump under minimum load while said valve means occupies said third one of said positions, f. differential-type abutment means having two abutments the area of the respective sides of one of which is less than the area of the respective sides of the other, and said abutment means being rigidly connected to said valve means for controlling the operation thereof to establish said communications, the respective sides of said one abutment being constantly connected to said delivery ports and selectively subject to the pressure in one of said delivery ports or in one of said releAse ports, and g. means for effecting variations of a pneumatic or hydraulic fluid pressure force on the respective opposite sides of the other of said two abutments to cause the operation of said valve means from said third position respectively to said one and another position so long as said pneumatic or hydraulic fluid pressure force on one of said respective opposite sides of said other abutment exceeds the hydraulic fluid pressure force on that side of said smaller abutment opposite said one side of said other abutment, and the operation of said valve means from either said one or said another position to said third position upon the reduction of the pneumatic or hydraulic fluid pressure force acting in one direction on said larger abutment to a value less than the hydraulic fluid pressure force acting in an opposite direction on said smaller abutment.