Infinitesimally variable hydraulic valve

A hydraulic valve provides infinitesimally variable flow in both directions through the valve including a position of no flow. The valve can be operated either hydraulically or mechanically. It includes a housing with a bore therethrough, a sleeve slidably mounted inside the bore, and endplates enclosing the ends of the bore. Ports allow controlled passage of hydraulic fluid through the housing, the sleeve, and extensions from the endplates so that fluid from a hydraulic pump enters ports in the housing, flows controllably through the valve, out one of the endplates, through a use apparatus, back into the remaining endplate, and to a sump.

BRIEF DESCRIPTION OF THE INVENTION 
This invention relates to a hydraulic valve which provides infinitely 
variable flow in both directions through the valve including a position of 
no flow. The valve can be operated either manually or hydraulically. 
The valve essentially comprises a housing with a bore therethrough. A 
sliding tube is mounted inside said housing. First and second end plates 
close each end of the bore, the end plates each have first and second 
tubular extensions axially disposed through the sliding tube. The facing 
ends of said tubular extensions are closed while the opposite ends are 
first and second function ports respectively. First and second control 
ports and first and second outlet control ports are provided through said 
housing and through said tubular extensions to said first and second 
function ports respectively. Mating ports are formed through said sliding 
tube in a manner to provide fluid communication through the first control 
port and the first and second tubular extension and the housing to the 
second control output port. When said sliding tube is in the opposite 
position, fluid communication is provided through the second control input 
port, the sliding cylinder and said second cylindrical extension, the 
first cylindrical extension, and the sliding cylinder and said second 
output central port.

Referring to all of the figures but in particular to FIG. 1, a continuously 
controllable valve is illustrated which has a housing 10, having a 
cylindrical bore 11 therethrough. Axially aligned in cylindrical bore 11 
is a control tube 12 which has a pair of inlet ports 13a and 13b. Opposite 
inlet ports 13a and 13b are outlet ports 14a and 14b. Housing 10 has a 
pair of corresponding inlet passages 15a and 15b which communicate with 
inlet port 16. A pair of outlet passages 17a and 17b communicate with an 
outlet port 18. It should be noted that inlet ports 13a and 13b are 
arranged so that one of the ports is closed to the flow of fluids from 
inlet passages 13a or 13b when one of the ports is axially aligned with a 
corresponding passage. It should also be noted that the diametrically 
opposite outlet port is likewise fully closed to the flow of fluids. 
Enclosing each end is a plate 19 and 20. End plates 19 and 20 are attached 
to housing 10 by a plurality of bolts 21 in the usual manner. Each end 
plate 19 and 20 has an extension cylinder 23 and 24 respectively which is 
attached at one end to end plates 19 or 20 and is closed at the other end 
by closing means 25 and 26 respectively. 
A pair of function ports 27 and 28 are formed through cylindrical 
extensions 23 and 24 respectively and communicate with ports 13a and 14a, 
and with 13b and 14b respectively through inlet ports 29a and 29b, and 
outlet ports 33a and 33b respectively which ports are formed through 
extensions 23 and 24 and are directly opposite the terminus of inlet 
passages 15a, 15b and 17a, 17b respectively. Ports 27 and 28 operate as 
either inlet or outlet ports depending on the position of control tube 12 
which operation will be described in a later portion of the specification. 
HYDRAULICALLY CONTROLLED EMBODIMENT 
The apparatus illustrated in FIG. 1 is a fully hydraulically operated 
embodiment. To accommodate hydraulic control of control tube 12, a 
partition 30 is mounted midway between the ends of control tube 12 in the 
space between the ends 25 and 26 of cylindrical extensions 23 and 24. A 
hydraulic power source and control apparatus 35 is coupled through a pair 
of tubes 36 and 37 to a pair of valves 38 and 39 respectively. Tubes 40 
and 40 couple the hydraulic output from valves 38 and 39 respectively to 
input ports 42 and 43 which convey the hydraulic output through each of 
the cylindrical extensions 23 and 24 respectively by means of a pair of 
bored holes 44 and 45 respectively. 
"O" rings 46a, 46b, 46c and 46d provide seals between control tube 12 and 
cylindrical extensions 23 and 24, and housing 10. A pair of seals 47a and 
47b likewise provide seals between each endplate 19 and 20, and housing 
10. Additional leakage protection can be afforded by a pair of channels 
48a and 48b which will cause any hydraulic fluid which passes seals 46a or 
46b to be drained into passages 17a or 17b respectively. A sump 31 is 
coupled through a pipe 32 to hydraulic power source 35. 
OPERATION 
The operator of the embodiment illustrated in FIG. 1 can be best understood 
by reference to FIGS. 2 and 3A, 3B and 3C. Referring in particular to FIG. 
3A, a hydraulic pump 50 is connected from its inlet port to a sump 51 
through a pipe 52. A pipe 53 will couple the outlet port 18 to sump 51. 
The output from pump 50 is coupled through a pipe 54 to a relief valve 55 
and through a pipe 56 to the inlet port 16. Pipe 57 couples relief valve 
55 to sump 51. A use item such as a hydraulic motor 60 has one port 
coupled through a pipe 61 to function port 28, and its remaining port 
coupled through a pipe 62 to function port 27. In the operational drawings 
FIGS. 3A through 3C, the control tube will be represented by a pair of 
vanes 65 and 66. 
The device operates in the following manner. In the FIG. 3A, vanes 65 and 
66 are in a neutral position allowing hydraulic fluid to flow equally 
through both passages 15a and 15b, and 17a and 17b in the direction of 
arrows 67a, 67b and 68a, 68b. Under these conditions, the pressure at 
ports 27 and 28 will be the same. Thus, hydraulic fluid can flow in either 
direction as indicated by arrows 69a or 69b, however, the hydraulic fluid 
will probably not flow in either direction if the pressures at ports 27 
and 28 are identical. In view of the above, no hydraulic fluid will be 
flowing through pipes 61 or 62 through motor 60 or other device 60. Motor 
60 will, therefore, not be rotating in either direction. If device 60 is a 
piston, then it will remain in one position. It should also be noted that 
if device 60 is a piston, then the pressure on each side of the piston is 
the same. Under these conditions, the piston will be hydraulically locked 
into its last position. 
Referring to FIG. 3B, if vanes 65 and 66 are in the position illustrated, 
then hydraulic fluid is flowing out of port 28, through device 60 and to 
port 27. Depending on the device 60, if it is a motor, it will be rotating 
at full rotational speed in one direction. Referring to FIG. 3C, vanes 65 
and 66 are in the opposite direction from that illustrated in FIG. 3A. 
Under these conditions, the flow of hydraulic fluid will be out of port 
27, through device 60 in the opposite direction as that illustrated in 
FIG. 3A, causing the device, if it is a motor, to rotate in the opposite 
direction at full rotation. It should be obvious that any position of 
vanes 65 or 66 between the two extremes illustrated in FIGS. 3A and 3C, 
will give a direction flow with a proportionally decreased rotation, 
depending on the positions of vanes 65 and 66. 
Returning to FIGS. 1, 3A, 3B and 3C, the control tube operates in the same 
manner as vanes 65 and 66. 
Tube 12 is positioned either at endplate 19 or endplate 20 hydraulically by 
hydraulic source 35 caused by applying a differential pressure on each 
side of partition 30. If the pressure is applied by valve 38 through pipe 
40, port 42 and bored hole 40 to the space between closing means 25 and 
partition 30. Hydraulic fluid ports out of the space between partition 30 
and closing means 26, through bored hole 45, port 43, pipe 41, valve 39 
and pipe 37 to hydraulic power source 35 and to a pipe 32 and a sump 31. 
The position of valves 38 and 39 will determine which space is filled with 
hydraulic fluid under pressure and which space is exhausted to the sump. 
It should be obvious that since both sides are filled with hydraulic 
fluid, closure of both valves or the discharge valve, will hydraulically 
leave control tubes in that position when the valve was closed. 
Assuming control tube 12 is in the position illustrated in FIG. 1, valve 38 
will be open to the pressure side of hydraulic source 35. Under these 
conditions, the flow of fluids through the control circuit is through 
inlet port, through control tube inlet port 13a (13b is blocked), through 
inlet port 29a of cylindrical extension 23 and out function port 27, 
through the use equipment flowing in the direction of arrow 47. The return 
from the use equipment is in the direction of arrow 48 through function 
port 28, through outlet port 33b of cylindrical extension 24, through 
outlet port 14b or control tube 12 and into outlet passage 17b to outlet 
port 18, where it returns to the sump. The configuration of FIG. 1 is the 
same as the illustrated usage in FIG. 3C. 
FIG. 2 illustrates the situation when control tube 12 is in the opposite 
position with partition 30 moved near closing means 25. In this 
illustration, hydraulic fluid under pressure enters pipe 41, through 
coupling or port 43, bored hole 45 to the space between closing means 26 
and partition 30 moving tube 12 toward closing means 25 forcing the 
hydraulic fluid out of the space between partition 30 and closing means 
25, through bored hole 44, port 42 and pipe 40 to hydraulic source 35 (not 
illustrated in FIG. 2) and probably to a sump. 
The use apparatus will get hydraulic fluid from a pump (see FIG. 3A) which 
fluid will enter inlet port 16, through inlet passages 15b, through port 
13b in control tube 12, through port 20b in extension 24 and out function 
port 28 in the direction of arrow 58. The fluid will then pass through the 
use apparatus (for example motor 60 in FIG. 3) and return in the direction 
of arrow 59 to function port 27. Port 13a is blocked hydraulic fluid must 
then return through port 33a, port 14a in control tube 12 to outlet 
passage 17a to outlet port 18 where it returns to a sump (see FIG. 3). 
It should be obvious from the above that if control tube 12 is 
hydraulically locked at any position between that illustrated in FIG. 1 
and FIG. 3, then all of the ports will be open to a degree depending upon 
the actual location of partition 30 with respect to closing means 25 and 
26. An in between position will divide the pressure between function ports 
27 and 28. If the partition 30 is exactly half way between closing means 
25 and 26, then function ports 27 and 28 would have equal pressure. If 
(see FIG. 3B) device 60 were a piston, it would be hydraulically locked in 
the position it was in at the time the locking situation occurred. 
MECHANICALLY-HYDRAULICALLY CONTROLLED EMBODIMENT 
Referring to FIGS. 4 through 7, a mechanically and hydraulically controlled 
embodiment is illustrated. Only the differences between the hydraulically 
controlled embodiment will be discussed. The operation of the control 
valve 12, aside from the mechanical method for axially shifting the 
control tube 12, is exactly the same as that already described in FIGS. 1 
through 3. The same numbers will be used for identical parts. 
The method for shifting control tube 12 axially comprises a handle 70 which 
is connected to a control ring segment 71 which in turn fits into a slot 
72 in housing 10 (see FIG. 4). Referring to FIG. 7, handle 70 is connected 
to ring segment 71 by means of a threaded portion 73 and is locked to 
segment 71 by a bolt 74 and washer 75. Handle 70 extends into and engages 
a slot 77 in control tube 12 and includes a cylindrical roller 76 which 
fits into slot 77. Handle 70 passes through a slot 79 in housing 10. 
The hydraulic method and apparatus for shifting control tube 12 along its 
axis as illustrated in FIGS. 1 and 2 is exactly the same. 
OPERATION 
The arrangement illustrated in FIGS. 4 through 7 provides precise control 
of the flow of hydraulic fluids from inlet port 16, to the use apparatus 
60 and to the outlet port 18. The flow control is as follows: Direction of 
flow, that is, which the fluid is flowing as illustrated in FIGS. 3A, 3B 
or 3C, depends upon the position of control 12, as previously discussed. 
The precise positioning of control tube 12, however, in order to control 
flow through port 13a or 13d, 14a or 14b require exact control of the 
hydraulic power source 35 and its respective control valves. Another way 
to accomplish this control is to move the control tube 12 completely 
toward end 19 or end 20 which will open ports 13a and 14b or 13b and 14a 
either partially or completely. Control of the flow can then be 
accomplished by moving handle 70 along slot 79 as illustrated in FIG. 5 
from the neutral or open position to a shifted position as illustrated in 
FIG. 6. The more handle 70 is moved along slot 79, the more port 14b is 
closed with respect to port 33b and passage 17b. If handle 70 is rotated 
completely, then port 13b is completely rotated away from port 33b and 
thus port 33b is completely cut off from the flow of hydraulic fluid. 
Inlet ports 13a and 29a will function in exactly the same manner. Slot 72 
retains ring segment 71 from movement along the axis of control tube 12. 
MECHANICAL EMBODIMENT 
A simplified mechanical embodiment of a portion of the valve is illustrated 
in FIG. 8. In this embodiment no hydraulic shifting apparatus is required 
such as hydraulic power source 35, its necessary valves, pipe, holes 45 
and 46 or partition 30 which function solely as a piston to shift control 
cylinder 12 toward end plates 19 or 20. 
In the mechanical embodiment handle 70 is attached directly to tube 12 on 
its outer periphery as illustrated in FIG. 8. Slot 78 must cut through 
housing 10 having the same length and direction as slot 77 in control tube 
12. 
OPERATION 
Instead of control tube 12 being moved hydraulically along the axis of tube 
12, it is moved mechanically along this axis by grasping handle 70 and 
pushing or pulling it in the desired direction as illustrated by arrows 
82. The tube can also be rotated on its axis by moving it in the direction 
of arrow 83. The longitudinal slot 78 can be made as wide as necessary to 
accommodate rotation of handle 70 to fully cut off ports 13a and 29b, 14b 
and 33b. 
CONCLUSIONS 
A fully controllable valve is disclosed which permits flow in either 
direction through a use apparatus such as a piston or motor. The valve 
also provides for precise control over the flow of hydraulic fluid 
regardless of the direction of flow through the use equipment. Since the 
valve will control both direction and flow it makes a valve function as a 
regulator valve because it will control pump pressure so that a pump with 
fixed displacement and pressure will act like a variable displacement pump 
or a switch plate pump. Further, the valve will provide movement fully in 
one direction and change directions of flow instantly at full pressure in 
the reverse direction. 
It is obvious that for illustration purposes, a separate hydraulic source 
was illustrated for operating the valve. The same hydraulic source can be 
used for the use apparatus as for the control of the valve if desired. It 
is also obvious that other combinations of hydraulic and mechanical 
control for tube 12 can be used and still be within the apparatus as 
claimed. 
It is also obvious that changes and modifications can be made in the 
apparatus as disclosed and still be within the spirit and scope of the 
invention as described in the specification and appended claims.