Pilot operator valve

A valve for directing pressurized fluid includes a fluid directional element for controlling fluid flow to a work member and a motor, and a one way flow member for controlling fluid flow to the work member. The one way flow member is actuated by a pilot operated actuator. The pilot operated actuator includes surfaces against which fluid pressure acts to move the actuator from a first position to a position actuating the one way flow member to allow flow to the work member. The valve further includes a capturing mechanism to hold the pilot operated actuator in its actuating position to hold the one way flow member in the actuated position allowing flow to and from the work member.

BACKGROUND OF THE INVENTION 
A. Field of the Invention 
The present invention relates to a valve for directing flow to a work 
member and a fluid motor to control the operation of each. 
B. Description of the Prior Art 
Typical lawn mowers employed to mow areas such as golf greens include mower 
reels that are raised and lowered by a hydraulic operated work member such 
as a hydraulic cylinder. A valve directs pressurized fluid to the work 
member and to the motor turning the reels. In this manner, the valve 
operates to control the lifting of the reels off the ground and the 
rotation of the reel motor as the vehicle is propelled from one green to 
another. In addition, for safety reasons as the reels are being lowered or 
raised, the valve is actuated such that the motor is not operated. 
In addition, it is also desirable that while the reels are in the lowered 
position to mow the green, the work member mechanism is in a "float" 
condition such that as the reels engage bumps or irregularities in the 
terrain, they may freely rise and fall or "float" with the terrain. 
Accordingly, the hydraulic fluid must be able to flow to and from the work 
member. 
Prior art valves employed to control the fluid to the work member and the 
reel motor use complex mechanisms including several components. 
Furthermore, complicated porting including several valve elements are 
necessary to provide the floating effect. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a new and improved valve 
for directing flow to a work member and a fluid motor. 
Another object of the present invention is to provide a new and improved 
valve for selectively directing fluid to the work member used to lift the 
reels of a grass mower and to the fluid motor that powers the reels. 
Briefly, the present invention is directed to a new and improved valve that 
may be employed for selectively controlling the direction of fluid flow to 
a work member and to a fluid actuator such as a motor. The valve is 
coupled to a source of pressurized fluid and is in fluid communication 
through a first port to the work member and through a second port to the 
fluid motor. The valve also includes a selectively operable, fluid 
directional control member that controls the fluid flow through the ports. 
Flow through the first port is also controlled by a one way valve. 
Operation of the one way valve is accomplished by a pilot actuated member. 
The pilot actuated member includes first and second pressure surfaces that 
are in fluid communication with the pressurized fluid source. This 
communication of pilot fluid is controlled by the directional control 
element. 
Also included in the valve is a capturing mechanism that captures the pilot 
actuated member in a position maintaining the one way valve in an open 
position.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
Having reference now to the drawings and initially to FIG. 1, there is 
illustrated a four-position valve generally designated by the reference 
numeral 10. The valve 10 may be employed to operate a single acting 
cylinder generally designated by the reference numeral 12 and a hydraulic 
motor designated by the numeral 14. One example of an employment of the 
valve 10 is in a reel mower of the type for mowing greens on a golf 
course. The motor 14 would be employed to power the reels and the cylinder 
12 corresponds to the cylinder for lifting and lowering the reels 13 
relative to the greens. 
The valve 10 includes a housing 16 with three fluid ports. The first port 
18 is adapted to be coupled to a hydraulic pump 20 that supplies 
pressurized fluid to the valve 10. The pump 20 is coupled through a filter 
22 to a reservoir 24 of hydraulic fluid. The housing 16 includes a second 
port 26 in fluid communication with the motor 14. The motor 14 is also in 
fluid communication with the reservoir 24. The third port 28 is in fluid 
communication with the hydraulic cylinder 12. 
To control fluid flow through the valve 10 from the inlet 18 to the outlets 
26 and 28, a main spool 30 is slideably mounted within an elongated bore 
32 in the housing 16. The spool 30 may be manually operated by the 
operator of the mower. 
The spool 30 is biased to a neutral position (FIG. 1) by a spring 34 
coupled to the end of the spool 30 and mounted within a spring housing 36. 
The spool 30 includes a narrowed portion 38 that defines a first 40 and a 
second 42 land thereon. In addition, the spool includes opposite end lands 
44 and 46. A second reduced portion 48 adjacent to the land 46 defines a 
detent portion 50 that upon axial movement of the spool 30, is engaged by 
biased ball detents 52 and 54 to lock the spool 30 in a desired position. 
The ball detents 52 and 54 are biased into engagement with the spool 30 by 
springs 56 that are mounted within a detent housing 58. The detent housing 
58 is secured to the valve housing 16, and the spring housing 36, in turn, 
is secured to the detent housing 58. 
The spool 30 may be axially moved within the housing 16 to direct fluid 
flow from the pump 20 through the coring or passages within the valve 
housing 16 to the outlets 26 and 28. More specifically, the housing 16 
includes first 60 and second 62 cores that are in fluid communication with 
the bore 32 and the tank or reservoir 24. In addition, associated with the 
outlet 26 is a core 64 in fluid communication with the bore 32. Further, 
in association with the outlet 28, the housing 16 includes a core 66 also 
in fluid communication with the bore 32. The inlet 18 includes a core 68 
in fluid communication with the bore 32. 
In the neutral position of the valve 10 (FIG. 1), the lands 40 and 42 are 
positioned within the cores 64 and 68 such that pressurized fluid 
introduced into the inlet 18 flows through the core 68 and along the bore 
32 to the cores 60 and 62 wherein the pressurized fluid is returned to the 
reservoir 24. In this manner, pressurized fluid does not flow to the motor 
14 or the cylinder 12. 
Control of the fluid to the outlet 28 is also controlled by a pilot 
operated detented check valve generally designated by the reference 
numeral 70. The check valve 70 includes a spring biased poppet valve 72 
that is biased into a valve seat 74 by a spring 76 mounted within the 
housing 16. The poppet valve 72 also includes an integral tubular 
extension 78 that abuts the forward end of a pilot operated spool valve 
80. The pilot spool 80 is slideably positioned within first 82 and second 
84 bores defined within the housing 16. The poppet valve 72 may be moved 
out of its seat 74 under the influence of pressurized fluid introduced 
into core 66 or under the influence of the pilot spool 80 through its 
engagement with the tubular extension 78. 
The pilot spool 80 includes a first end 86 of a first cross-sectional area 
and a second end 88 of a second cross-sectional area that is smaller than 
the cross-sectional area of the end 86. In addition, the pilot spool 80 
includes an axially extending internal passage 90 that at one end is in 
fluid communication with a chamber 92 defined between the end of the bore 
84 and the end 88 of the spool 80. The inlet 94 of the passage or conduit 
90 is in fluid communication with the bore 82 that in turn is in fluid 
communication with a pilot fluid passage 96. The passage 96 is also in 
fluid communication with the bore 32. 
Accordingly, the position of the pilot spool 80 within the bores 82 and 84 
may be varied through the introduction of pressurized fluid to the passage 
96. More specifically, if pressurized fluid is introduced to the passage 
96, it flows through the passage 90 to the chamber 92 resulting in a shift 
of the pilot spool 80 within the bores 82 and 84. In the neutral position 
of the valve 10, however, no pressurized fluid is introduced to the 
passage 96 since the fluid is vented to the cores 60 and 62. Consequently, 
the pilot spool 80 is biased to its rightmost position as illustrated in 
FIG. 1 under the influence of the spring 76 and the poppet valve 72 is 
positioned in the seat 74. In this position, fluid may not flow out of the 
cylinder 12 and the reels 13 are locked into the selected position. 
Having reference now to FIG. 2, if it is desired to raise the mower reels 
13, the main spool 30 is shifted in the direction of the arrow 98 against 
the bias of the spring 34. In this position land 40 is in a sealing 
position within the bore 32 whereas land 42 is positioned within core 64. 
The land 44 is also sealingly positioned within the bore 32 and blocks 
fluid flow to the core 60 and thus to the tank 24. 
In this position of the valve 10, pressurized fluid from the pump 20 flows 
through the core 68 along the bore 32 and through the core 66. The fluid 
pressure acts against the poppet valve 72 with sufficient pressure to 
shift the poppet valve 72 out of its seat 74 allowing fluid flow across 
the poppet valve 72, through the outlet 28 to the cylinder 12. The 
introduction of pressurized fluid to the cylinder 12 lifts the reels 13 
off of the ground. 
Simultaneously, fluid pressure is also introduced against end 86 of the 
pilot spool 80 and also to the end 88 through the passages 96 and 90. As a 
result of the larger area of the end 86 relative to the end 88, however, 
the pilot spool 80 is not shifted within the bores 82 and 84. 
In addition, in this position of the spool 30, fluid may flow from the 
motor 14 through the core 64 and along the bore 32 to core 62 and the tank 
24. Thus the motor 14 is not powered by pressurized fluid and the reels 13 
are not operated in the raised position. 
During the operation of the mower, it is desired to have the reels 13 
positioned on the ground or green while the motor 14 is operated by 
pressurized fluid to power the reels 13. Due to the uneven nature of 
greens or similar type surfaces and the bumps that may be experienced by 
the mower, however, it is not desired that the reels 13 be held in a rigid 
position but rather be allowed to move freely with the contour of the 
ground. This condition is termed the float condition whereby the reels 13 
float relative to the cylinder 12 to move with the contour of the ground. 
The float mode of operation may be accomplished by moving the main spool 30 
in the direction indicated by the arrow 100 (FIG. 3) until the lands 40 
and 42 are both in a sealing position within the bore 32. In this position 
hydraulic fluid from the pump 20 is prevented from flowing along the bore 
32 and is introduced under full pressure to passage 96. 
Pressurized fluid from passage 96 flows along the passage 90 to the chamber 
92 and interacts against the end 88 of the pilot spool 80. This pressure 
is sufficient to overcome the bias of the spring 76 causing the pilot 
spool 80 to shift within the bores 82 and 84. Through the interaction of 
the spool 80 with the tubular extension 78 the poppet valve 72 is moved 
out of its seat 74. In this position, fluid may flow from the cylinder 12 
through the outlet 28 and the core 66 to the core 60 and then to the tank 
24. This allows the lowering of the reels 13. 
As a result of the employment of the pilot spool 80, the reels 13 may be 
lowered while at the same time the fluid does not flow to the motor 14 due 
to the land 42 and the reels 13 are not operated. This provides a 
significant safety feature. In addition, pressurized fluid to the core 66 
is prevented by the land 40 allowing free fluid flow in the cores 66 and 
60. 
In the float position of the pilot spool 80, the pilot spool 80 is held by 
a ball detent 102 interacting with a reduced portion 104 defined on the 
pilot spool 80. The ball detent 102 is biased into the reduced portion 104 
by a spring 106. Once in this position, the interaction of the ball detent 
102 with the pilot spool 80 will hold the pilot spool 80 thereby holding 
the poppet valve 72 out of its seat allowing the reels 13 to float even 
though pressurized fluid is no longer introduced to the chamber 92. 
In this position of the pilot spool 80, once the reels 13 have been lowered 
to the desired position, the spool 30 may be again shifted in a leftward 
direction as indicated by the arrow 108 (FIG. 4). In this position land 40 
is located within the bore 32, however, the land 42 is positioned within 
the core 68. Accordingly, pressurized fluid may flow through the core 68 
along the bore 32 to the core 64. Thereafter, the pressurized fluid is 
introduced to the motor 14 driving the reels. At the same time land 40 
prevents the introduction of pressurized fluid to the core 66 and since 
the spool 80 is held in the float position by the detent ball 102, the 
reels 13 are allowed to "float" over the contour of the green. In addition 
the detent balls 52 and 54 engage the reduced portion 50 of the main spool 
30 holding the main spool 30 in this position. Consequently, the operator 
may release the main spool 30 and the vehicle will continue to operate in 
the desired mode. 
Upon completion of mowing the green, the reel 13 may be raised by moving 
the main spool 30 to the position illustrated in FIG. 2. In this position, 
pressurized fluid is again introduced to core 66 interacting against end 
86. The resultant force is sufficient to overcome the bias of the detent 
ball 102 shifting the pilot spool 80 to the position illustrated in FIG. 
2. The pressurized fluid is also sufficient to bias the poppet valve 72 
out of its seat 74 allowing pressurized fluid to flow out the outlet 28 to 
the cylinder 12 thus raising the reels 13. 
To prevent damage to the valve 10 or other components of the system due to 
undesirable pressures within the housing 16, a relief valve generally 
designated by the reference numeral 110 is included. The relief valve 110 
includes a passage 112 in fluid communication with the core 68 and with 
the core 62 and thus the tank 24 across a valve element 114. The valve 
element 114 is biased into sealing engagement with the passage 112 by a 
spring 116. Once sufficient pressure of a predetermined magnitude develops 
within the core 68, this pressure moves the valve element 114 out of 
sealing engagement with the passage 112 (FIG. 4) allowing fluid flow to 
bypass the remaining part of the valve 10 thereby preventing damage to the 
valve 10 due to pressure. 
While the invention has been described with reference to details of the 
illustrated embodiment, it should be understood that such details are not 
intended to limit the scope of the invention as defined in the following 
claims.