Abstract:
A control valve system having a housing defining an inlet, an outlet, and an exhaust. A first passage extends between the inlet and the outlet and a second passage extends between the outlet and the exhaust. The control valve system includes a first valve disposed within the first passage. The first valve is movable between a closed position and an opened position. Similarly, the control valve system includes a second valve disposed within the second passage. The second valve is movable between a closed position and an opened position. Furthermore, the control valve system includes a regulator circuit operably coupled to the housing, which outputs a pilot pressure in response to an inlet pressure. An actuating member is slidably disposed within the housing and moveable in response to a pressure differential between the outlet and the pilot pressure. The actuating member independently actuates the first valve and the second valve to provide a quick pressure and exhaust feature.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention generally relates to control valves, and more particularly, relates to a variable pressure fluid control valve that includes a quick exhaust control feature selectively actuated in response to the regulated output of a proportional regulator.  
         BACKGROUND OF THE INVENTION  
         [0002]    Control valves having a pressure regulator are often used to exhaust excess fluid pressure. Traditionally, these pressure regulators act to relieve fluid pressure by exhausting the fluid through a fluid passage within the pressure regulator assembly. However, often fluid relief passages are relatively small and require an extensive amount of time to exhaust the fluid pressure. Accordingly, these known pressure regulators may not maximize the fluid exhaust rate of the control valve.  
           [0003]    Control valves often employ pressure regulators to maintain a predetermined fluid pressure in response to a control signal. However, control valves in general are not particularly suited to operate as pressure regulators, since they are unable to rapidly adjust to a higher pressure and rapidly adjust to a lower pressure. Specifically, these control valve may be capable of rapidly increasing pressure, however they are notoriously slow at reducing pressure. Hence, they may not supply sufficient control of the fluid pressure under all operating parameters.  
           [0004]    Accordingly, there exists a need in the relevant art to provide a control valve capable of providing variable fluid regulation while simultaneously capable of providing rapid fluid pressure exhaust. Furthermore, there exists a need in the relevant art to provide a single control valve capable of providing variable fluid regulation and rapid fluid pressure exhaust in response to a simple pilot pressure. Still further, there is a need in the relevant art to provide a control valve capable of overcoming the disadvantages of the prior art.  
         SUMMARY OF THE INVENTION  
         [0005]    A control valve system having an advantageous construction is provided. The control valve system including a housing defining an inlet, an outlet, and an exhaust. A first passage extends between the inlet and the outlet and a second passage extends between the outlet and the exhaust. The control valve system includes a first valve disposed within the first passage. The first valve is movable between a closed position and an opened position. Similarly, the control valve system includes a second valve disposed within the second passage. The second valve is movable between a closed position and an opened position. Furthermore, the control valve system includes a regulator circuit operably coupled to the housing, which outputs a pilot pressure in response to an input signal. An actuating member is slidably disposed within the housing and moveable in response to a pressure differential between the outlet and the pilot pressure. The actuating member independently actuates the first valve or the second valve to provide a quick pressure or exhaust feature.  
           [0006]    The control valve system of the present invention possesses the ability to rapidly respond to a pilot pressure and, consequently, rapidly change the output fluid pressure to a higher or lower pressure in response to a pilot pressure signal while providing fluid flow to a cylinder or device. The control valve system of the present invention can start at any fluid pressure in its range, including zero pressure, and rapidly adjust to any other pressure within its range. It is unique in its ability to change its pressure higher or lower quickly while simultaneously providing fluid flow.  
           [0007]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0009]    [0009]FIG. 1 is a circuit diagram of a variable pressure control device according to the principles of the present invention illustrated in a deactuated position;  
         [0010]    [0010]FIG. 2 is a cross-sectional view of the variable pressure control device in an unpressurized and deactuated position,  
         [0011]    [0011]FIG. 3 is a cross-sectional view of the variable pressure control device in a first pressurized position with a lower poppet member in an unseated position;  
         [0012]    [0012]FIG. 4 is a cross-sectional view of the variable pressure control device in the pressurized position;  
         [0013]    [0013]FIG. 5 is a cross-sectional view of the variable pressure control device in the pressurized position with an upper poppet member in an unseated position; and  
         [0014]    [0014]FIG. 6 is a cross-sectional view of the variable pressure control device in a pressurized and deactuated position. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]    The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0016]    Referring now to the drawings in which like reference numerals designate like or corresponding parts throughout the several views, there is shown a variable pressure control device  10 , which is designated generally by the reference numeral  10 . Variable pressure control device  10  is shown as a fluid circuit in FIG. 1 and as a fluid control valve in FIG. 2.  
         [0017]    Referring in particular to FIG. 2, variable pressure control device  10  comprises a main valve assembly  12 , a quick exhaust valve  14 , and a proportional regulator  16 . Main valve assembly  12  includes a main body portion  18 , a secondary body portion  20 , an upper end cap  22 , and a lower end cap  24 . Main body portion  18  is positioned adjacent to and in contact with secondary body portion  20 . A seal  26  is disposed between main body portion  18  and secondary body portion  20  to seal the interface therebetween. Upper end cap  22  is positioned adjacent to and in contact with secondary body portion  20 . A seal  28  is disposed between upper end cap  22  and secondary body portion  20  to seal the interface therebetween. Lower end cap  24  is positioned adjacent to and in contact with main body portion  18 . A seal  30  is disposed between lower end cap  24  and main body portion  18 . Main body portion  18 , secondary body portion  20 , upper end cap  22 , and lower end cap  24  are coupled together via conventional fasteners.  
         [0018]    Main valve assembly  12  further includes a fluid inlet passage  32 , a fluid outlet passage  34 , fluid exhaust passage  36 , a valve bore  38 , and a piston bore  40 . Disposed within valve bore  38  and piston bore  40  is a valve member  42 . Valve member  42  comprises a lower poppet member  44 , an upper poppet member  46 , a piston  48 , and a valve stem  50 . Lower poppet member  44  includes a base portion  52  slidably disposed within a chamber  54  of valve bore  38 . A seal  56  is disposed between base portion  52  and lower end cap  24  which seals chamber  54  from fluid inlet passage  32 . Lower poppet member  44  further includes a face portion  58  that selectively engages a seat  60  formed in main body portion  18  of main valve assembly  12 .  
         [0019]    Lower poppet member  44  is normally biased via a spring  62  into a seated position where face portion  58  of lower poppet member  44  contacts seat  60  of main valve assembly  12  to prevent fluid flow between fluid inlet passage  32  and fluid outlet passage  34 . As will be described below, lower poppet member  44  is further positionable to an unseated position where face portion  58  of lower poppet member  44  is spaced apart from seat  60  of main valve assembly  12  to enable fluid flow between fluid inlet passage  32  and fluid outlet passage  34 . Lower poppet member  44  still further includes a fluid passage  64  formed through face portion  58  to enable fluid to flow between chamber  54  and fluid outlet passage  34 . Fluid passage  64  equalizes the fluid pressure between chamber  54  and fluid outlet passage  34 .  
         [0020]    Similarly, upper poppet member  46  includes a base portion  66  slidably disposed within a chamber  68  of valve bore  38 . A seal  70  is disposed between base portion  66  and secondary body portion  20  which seals chamber  68  from fluid exhaust passage  36 . Upper poppet member  46  further includes a face portion  72  that selectively engages a seat  74  formed in main body portion  18  of main valve assembly  12 . It should be noted that upper poppet member  46  and lower poppet member  44  are preferably of identical construction to simplify construction and assembly.  
         [0021]    Upper poppet member  46  is normally biased via a spring  76  into a seated position where face portion  72  of upper poppet member  46  contacts seat  74  of main valve assembly  12  to prevent fluid flow between fluid outlet passage  34  and fluid exhaust passage  36 . As will be described below, upper poppet member  46  is further positionable into an unseated position where face portion  72  of upper poppet member  46  is spaced apart from seat  74  of main valve assembly  12  to enable fluid flow between fluid outlet passage  34  and fluid exhaust passage  36 .  
         [0022]    Piston  48  is slidably disposed within piston bore  40 , thereby defining an upper piston chamber  78  and a lower piston chamber  80 . A seal  82  is disposed between piston  48  and piston bore  40  which seals upper piston chamber  78  from lower piston chamber  80 . Piston  48  is fixedly mounted to valve stem  50  for movement therewith via fastener  84 . More particularly, piston  48  includes an aperture  86  formed therethrough that is sized to receive an upper end  88  of valve stem  50 . Piston  48  is then captured between a first shoulder  90  on valve stem  50  adjacent upper end  88  and fastener  84 . A fluid passage  92 , surrounding valve stem  50 , extends between lower piston chamber  80  and chamber  68 .  
         [0023]    Valve stem  50  further includes a second shoulder  94  and a third shoulder  96 . Second shoulder  94  is sized to engage face portion  72  of upper poppet member  46  in order to selectively move upper poppet member  46  upward against the biasing force of spring  76  in response to upward movement of piston  48 . Similarly, third shoulder  96  is sized to engage face portion  58  of lower poppet member  44  in order to selectively move lower poppet member  44  downward against the biasing force of spring  62  in response to downward movement of piston  48 . A lower end  98  is slidably disposed within a sleeve  100 . Sleeve  100  is positioned within a guide bore  102 .  
         [0024]    A fluid passage  103  extends between fluid outlet passage  34  and lower piston chamber  80 . Fluid passage  103  includes a seal  104  disposed along fluid passage  103  between main body portion  18  and secondary body portion  20  to seal the interface therebetween.  
         [0025]    Still referring to FIG. 2, quick exhaust valve  14  of variable pressure control device  10  includes a body  105 , a valve bore  106 , a flow-through passage  108 , an inlet pilot passage  110 , an outlet pilot passage  112 , and an exhaust passage  114 . A quick exhaust poppet member  116  is slidably disposed within valve bore  106  of quick exhaust valve  14 , thereby defining an inlet chamber  118  and an outlet chamber  120 . Inlet chamber  118  is fluidly coupled with an outlet of proportional regulator  16 . Outlet chamber  120  is fluidly coupled with upper piston chamber  78  via outlet pilot passage  112 . Quick exhaust poppet member  116  includes a face portion  122  that selectively engages a seat  124  formed on an end of exhaust passage  114  in response to a pressure differential between outlet chamber  120  and inlet chamber  118 . Quick exhaust poppet member  116  is positionable in a seated position so as to contact seat  124  of exhaust passage  114  to prevent fluid flow between upper piston chamber  78  and exhaust passage  114 . Quick exhaust poppet member  116  is further positionable in an unseated position wherein face portion  122  of quick exhaust poppet member  116  is spaced apart from seat  124  of exhaust passage  114  to enable venting of fluid within upper piston chamber  78 . Quick exhaust poppet member  116  further includes a bypass leg  126  extending around the periphery of quick exhaust poppet member  116  that is normally biased to engage the wall of valve bore  106 . Bypass leg  126  permits fluid flow thereby in response to a predetermined fluid pressure differential between inlet pilot passage  110  and outlet pilot passage  112 . Quick exhaust valve  14  is mounted to secondary body portion  20  of main valve assembly  12 .  
         [0026]    Proportional regulator  16  is mounted to quick exhaust valve  14  in fluid communication with main valve assembly  12  for controlling the output and/or exhaust of main valve assembly  12 . Specifically, a fluid passage  128  extends between fluid inlet passage  32  of main valve assembly  12  to flow-through passage  108  of quick exhaust valve  14 . In turn, flow-through passage  108  of quick exhaust valve  14  is fluidly coupled to an inlet of proportional regulator  16 , thereby providing an input fluid source for operation of proportional regulator  16 . A seal  130  and a seal  132  are disposed between flow-through passage  108  and secondary body portion  20  of main valve assembly  12  and proportional regulator  16 , respectively, to seal the interface therebetween. Similarly, a seal  134  is disposed between inlet pilot passage  110  and an outlet of proportional regulator  16 . Likewise, a seal  136  is disposed between outlet pilot passage  112  and secondary body portion  20  of main valve assembly  12  to seal the interfaces therebetween.  
         [0027]    As best seen in FIG. 1, proportional regulator  16  generally includes a variable pressure valve  138  that is adjustable by an operator to control a pilot pressure output through a proportional pilot valve  140 . A pressure transducer  142  supplies fluid pressure information to variable pressure valve  140 .  
       Operation  
       [0028]    [0028]FIGS. 1 and 2 illustrate variable pressure control device  10  in its deactuated or neutral position with no fluid pressure supplied to fluid inlet passage  32 . In this position, spring  62  biases lower poppet member  44  upward such that face portion  58  of lower poppet member  44  is seated against seat  60  of main body portion  18 , thereby closing communication between fluid inlet passage  32  and fluid outlet passage  34 . Similarly, spring  76  biases upper poppet member  46  downward such that face portion  72  of upper poppet member  46  is seated against seat  74  of main body portion  18 , thereby closing communication between fluid outlet passage  34  and fluid exhaust passage  36 . Piston  48  is in a neutral position as a result of the generally equal fluid pressure within upper piston chamber  78  and lower piston chamber  80 . Accordingly, valve stem  50  is positioned such that neither second shoulder  94  nor third shoulder  96  exert an unseating force against upper poppet member  46  or lower poppet member  44 , respectively. Likewise, due to the generally equal fluid pressure within output pilot passage  112  and inlet pilot passage  110 , quick exhaust poppet member  116  is in an unseated position relative to seat  124  of exhaust passage  114 . In this unseated position, fluid within upper piston chamber  78  and output pilot passage  112  is permitted to vent through exhaust passage  114 . Accordingly, upper piston chamber  78 , lower piston chamber  80 , fluid outlet passage  34 , fluid inlet passage  32 , and fluid exhaust passage are each generally at ambient pressure.  
         [0029]    [0029]FIG. 3 illustrates the first introduction of fluid pressure within variable pressure control device  10 . Specifically, fluid pressure is introduced into fluid inlet passage  32 , fluid passage  128 , flow-through passage  108 , and into the inlet of proportional regulator  16 . Proportional regulator  16  outputs an output pilot pressure or regulator pressure in accordance with control signal applied to proportional pilot  140 . This outlet pilot pressure from proportional regulator  16  is introduced into inlet pilot passage  110  and, thus, acts upon a backside of quick exhaust poppet member  116 . This pilot pressure causes face portion  122  of quick exhaust poppet member  116  to seat against seat  124  of exhaust passage  114 , thereby closing communication between upper piston chamber  78  and exhaust passage  114 . Simultaneously, bypass leg  126  of quick exhaust poppet member  116  folds to enable fluid flow from inlet pilot passage  110  to outlet pilot passage  112  and upper piston chamber  78 . With reference to FIG. 1, quick exhaust valve  14  would be positioned as shown such that fluid flows throught the uppermost portion of valve  14 .  
         [0030]    Fluid pressure within upper piston chamber  78  is greater than the fluid pressure within lower piston chamber  80 , thereby exerting a downward force upon piston  48 . This downward force on piston  48  causes piston  48  and valve stem  50  to translate downward. As seen in FIG. 3, downward movement of valve stem  50  causes third shoulder  96  to engage face portion  58  of lower poppet member  44 , thereby unseating lower poppet member  44  from seat  60  and permitting fluid flow from fluid inlet passage  32  to fluid outlet passage  34 . This position would be the right most position of valve  12  illustrated in FIG. 1. As seen in FIG. 4, fluid flow from fluid inlet passage  32  to fluid outlet passage  34  will continue until the force from the fluid pressure within fluid outlet passage  34 , fluid passage  103 , and lower piston chamber  80  and spring force of spring  62  generally equals the fluid pressure in upper piston chamber  78 , thereby causing piston  48  and valve stem  50  to return to a neutral position and lower poppet member  44  to reseat on seat  60  due to the force of spring  62 .  
         [0031]    [0031]FIG. 5 illustrates the quick exhausting of main valve assembly  12 . Specifically, in this mode the outlet pressure of proportional regulator  16  is reduced such that the fluid pressure at inlet pilot passage  110  is less than the fluid pressure in upper piston chamber  78  of main valve assembly  12 . This pressure differential causes quick exhaust poppet member  116  to slide within valve bore  106  and unseat from seat  124  of exhaust passage  114 . The unseating of quick exhaust poppet member  116  from exhaust passage  114  enables fluid pressure within upper piston chamber  78  and outlet pilot passage  112  to vent through exhaust passage  114 , thereby reducing the fluid pressure within upper piston chamber  78  and outlet pilot passage  112  to the pressure in the outlet of pilot passage  110 , which is effectively equal to atmosphere. Relative to FIG. 1, fluid would vent through the lowermost portion of quick exhaust valve  14 . As the fluid pressure within upper piston chamber  78  decreases, the pressure differential between lower piston chamber  80  and upper piston chamber  78  exerts an upward force upon piston  48 . This upward force on piston  48  causes piston  48  and valve stem  50  to translate upward. As seen in FIG. 5, upward movement of valve stem  50  causes second shoulder  94  to engage face portion  72  of upper poppet member  46 , thereby unseating upper poppet member  46  from seat  74  and permitting the quick exhaust of fluid from fluid outlet passage  34  to fluid exhaust passage  36 . That is, valve  12  would be translated to its leftmost position (FIG. 1). As seen in FIG. 6, fluid flow from fluid outlet passage  34  to fluid exhaust passage  36  will continue until the force from the fluid pressure within fluid outlet passage  34 , fluid passage  103 , and lower piston chamber  80  and the spring force from spring  76  generally equal the fluid pressure in upper piston chamber  78  (which is effectively equal to ambient), thereby causing piston  48  and valve stem  50  to return to a neutral position and upper poppet member  46  to reseat on seat  74  by the force of spring  76 .  
         [0032]    Variable pressure control device  10  of the present invention possesses the ability to rapidly respond to a pilot pressure and, consequently, rapidly change the output fluid pressure to a higher or lower pressure in response to a pilot pressure signal while providing fluid flow to a cylinder or device. Variable pressure control device  10  of the present invention can start at any fluid pressure in its range, including zero pressure, and rapidly adjust to any other pressure within its range. It is unique in its ability to change its pressure higher or lower quickly while simultaneously providing fluid flow.  
         [0033]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.