Abstract:
A hydraulic system comprises a hydraulic fluid circuit including a hydraulic pressure reducer. The hydraulic fluid circuit comprises a supply line and a return line. A quick connect coupler is fluidly coupled to each of the supply line and the return line. A hydraulic control valve set is coupled to the supply line and the return line downstream of the quick connect couplers. A hydraulic piston cylinder assembly is coupled to the supply line and the return line downstream of said hydraulic control valve set. The hydraulic pressure reducer is fluidly coupled to at least one of the supply line and the return line between the quick connect coupler and the hydraulic control valve set.

Description:
BACKGROUND 
       [0001]    The present disclosure is directed to a device for controlling hydraulic pressure that has accumulated in a static hydraulic system. Specifically, the disclosure describes a system and device that prevents hydraulic fluid systems from over pressurizing and subsequently leaking hydraulic fluid to the environment. 
         [0002]    The present invention generally relates to an apparatus for relieving hydraulic pressure in a hydraulic hose connected with hydraulically powered equipment in which the hose supplies hydraulic pressure to the equipment from a source of hydraulic pressure or returns hydraulic pressure from the equipment to a hydraulic fluid reservoir. The hydraulic hose is separable and connected to a hydraulic source by a quick coupler including a male and female component each of which includes a valve that is open as long as the quick coupler components are connected but will immediately close when the quick coupler components are disconnected thereby trapping hydraulic pressure in the hose. Any entrapped hydraulic pressure within the hose exerts pressure on the valve in the quick coupler component on the hose which makes it quite difficult to reconnect the male and female components of a quick coupler when reconnecting the hose to a hydraulic pressure source. 
         [0003]    Referring to  FIG. 1 , hydraulically powered equipment  10  is used for various purposes such as on tractor trailer trucks  12  (shown), various agricultural equipment, industrial equipment, fork lifts, and the like. The equipment usually includes a hydraulic ram in the form of a piston and cylinder assembly  14 , a hydraulic motor or the like connected to a source of hydraulic pressure  16  by flexible hoses  18  with control valves  20  being provided for controlling operation of the hydraulically powered equipment  10 . In many installations, such as a hydraulic trailer  22 , the hydraulic hoses  18  are connected to another hose or a tractor mounted hydraulic control valve by a quick coupler  24  which includes a male component and a female component which are quickly and easily connected by merely inserting the male component into the female component with interconnecting latching or detent structure securing the two components in connected, sealed relation. 
         [0004]    Each of the two components in the quick coupler have a spring biased valve, usually a steel ball valve, engaged with a valve seat when the quick coupler components are disconnected. When the quick coupler  24  components are connected, the valves contact each other and move each other away from the valve seat thereby communicating the hose with another hose or a source of hydraulic pressure. 
         [0005]    When the hydraulic trailer  22  is to be disconnected from the tractor  12 , the hydraulic control valve is closed and the quick coupler components disconnected by manually releasing the latch or detent structure with the valves closing when the quick coupler components are separated. 
         [0006]    The steel ball in the quick coupler connected to the hose is pushed against its seat by the pressure within the hose which prevents hydraulic fluid or oil in the hose from draining onto the ground surface or the like. 
         [0007]    Frequently, the hydraulic fluid on the trailer  22  will become heated and due to expansion of the hydraulic fluid in response to temperature changes will apply force to the hydraulic hose and maintain relatively high pressure in the hose. Then, when it is desired to recouple the quick coupler component on the hose to a quick coupler component connected to the tractor mounted hydraulic control valve, or to connect it to another hose, it is quite difficult to move the steel ball valve in the quick coupler component on the hose away from the valve seat. 
         [0008]    The pressure in the hydraulics of the hydraulic trailer can reach as much as 600 psi. The high pressure has resulted in hydraulic fluid leaks to the environment. 
         [0009]    What is needed is a hydraulic pressure reducer to prevent the hydraulic fluid from becoming pressurized when the trailer is disconnected. 
       SUMMARY 
       [0010]    In accordance with the present disclosure, there is provided a hydraulic pressure reducer comprising a body having a first section and a second section coupled to the first section. A diaphragm is coupled between the first section and the second section. The first section and the second section define a fluid reservoir and an expansion region on opposite sides of the diaphragm. A biasing element is located in the expansion region, the biasing element is coupled to the diaphragm and is configured to bias the diaphragm responsive to a hydraulic fluid pressure acting on the diaphragm. 
         [0011]    In an exemplary embodiment the fluid reservoir is configured to change volume responsive to a change of hydraulic fluid volume. 
         [0012]    In an exemplary embodiment the diaphragm is configured to flex responsive to a change of hydraulic fluid volume, the hydraulic fluid volume comprising one of an expansion and a contraction. 
         [0013]    In an exemplary embodiment the biasing element is configured to exert a force on the diaphragm and contract a volume of the fluid reservoir. 
         [0014]    In an exemplary embodiment the biasing element is configured to change position responsive to a change of hydraulic fluid volume, the hydraulic fluid volume comprising one of an expansion and a contraction. 
         [0015]    In an exemplary embodiment the biasing element comprises a disc coupled to a first end of a rod, the rod extends through the second section of the body. 
         [0016]    In an exemplary embodiment the rod comprises a second end opposite the first end, the second end of the rod extends outside of the second section, an adjustable member coupled to the second end, the adjustable member is configured to change a length of travel of the rod relative to the second section of the body. 
         [0017]    In an exemplary embodiment the hydraulic pressure reducer further comprises a spring coupled to the disc, the spring is configured to apply a force to the disc opposite the hydraulic fluid pressure. 
         [0018]    In an exemplary embodiment the biasing element comprises a cushion of air in the expansion region. 
         [0019]    In an exemplary embodiment the diaphragm comprises a piston disposed in a cylinder. 
         [0020]    In an exemplary embodiment the piston disposed in the cylinder is coupled to the biasing element within the expansion region. 
         [0021]    In an exemplary embodiment the piston disposed in the cylinder is coupled to the biasing element, the biasing element comprising a pair of springs coupled to an exterior of the body. 
         [0022]    In another exemplary embodiment a hydraulic system comprises a hydraulic fluid circuit including a hydraulic pressure reducer. The hydraulic fluid circuit comprises a supply line and a return line. A quick connect coupler is fluidly coupled to each of the supply line and the return line. A hydraulic control valve set is coupled to the supply line and the return line downstream of the quick connect couplers. A hydraulic piston cylinder assembly is coupled to the supply line and the return line downstream of said hydraulic control valve set. The hydraulic pressure reducer is fluidly coupled to at least one of the supply line and the return line between the quick connect coupler and the hydraulic control valve set. 
         [0023]    In an exemplary embodiment the hydraulic system further comprises a hydraulic trailer supporting the hydraulic fluid circuit. 
         [0024]    In an exemplary embodiment the hydraulic system is detachably coupled to a hydraulic power source, the hydraulic power source coupled to at least one of a tractor trailer truck, an agricultural equipment device, a fork lift, an industrial equipment device. 
         [0025]    In an exemplary embodiment the hydraulic pressure reducer comprises a body having a first section and a second section coupled to the first section; a diaphragm is coupled between the first section and the second section; the first section and the second section defining a fluid reservoir and an expansion region on opposite sides of the diaphragm; and a biasing element located in the expansion region, the biasing element coupled to the diaphragm and is configured to bias the diaphragm responsive to a hydraulic fluid pressure acting on the diaphragm. 
         [0026]    In accordance with the present disclosure, there is provided a method of reducing excessive pressure in static hydraulic systems comprises coupling a hydraulic pressure reducer to the hydraulic system, wherein the hydraulic system comprises a hydraulic fluid circuit, the hydraulic fluid circuit comprises a supply line and a return line; a quick connect coupler is fluidly coupled to each of the supply line and the return line; a hydraulic control valve set is coupled to the supply line and the return line downstream of the quick connect couplers, a hydraulic piston cylinder assembly is coupled to the supply line and the return line downstream of the hydraulic control valve set; and the hydraulic pressure reducer is fluidly coupled to at least one of the supply line and the return line between the quick connect coupler and the hydraulic control valve set; wherein the hydraulic pressure reducer comprises a body having a first section and a second section coupled to the first section; a diaphragm is coupled between the first section and the second section; the first section and the second section defining a fluid reservoir and an expansion region on opposite sides of the diaphragm; and a biasing element is located in the expansion region, the biasing element is coupled to the diaphragm and configured to bias the diaphragm responsive to a hydraulic fluid pressure acting on the diaphragm; and changing a volume of the fluid reservoir and the expansion region of the hydraulic pressure reducer responsive to a change in a hydraulic fluid volume in the hydraulic system. 
         [0027]    In an exemplary embodiment the method further comprises reconnecting a hydraulic power source to the hydraulic system quick connect coupler in the absence of hydraulic fluid pressure. 
         [0028]    In an exemplary embodiment the method further comprises reducing hydraulic fluid leakage from the quick connect coupler by reducing hydraulic fluid pressure acting on the quick connect coupler. 
         [0029]    In an exemplary embodiment the method further comprises replacing hydraulic fluid into the hydraulic system responsive to reconnection of the hydraulic power source to the quick connect coupler. 
         [0030]    In an exemplary embodiment the method further comprises resetting the pressure reducer biasing element responsive to hydraulic fluid pressure changes. 
         [0031]    Other details of the hydraulic pressure reducer are set forth in the following detailed description and the accompanying drawings wherein like reference numerals depict like elements. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]      FIG. 1  is an illustration of a tractor trailer with hydraulic trailer; 
           [0033]      FIG. 2  is an illustration of an exemplary hydraulic system with hydraulic pressure reducer; 
           [0034]      FIG. 3  is an illustration of the exemplary hydraulic pressure reducer; 
           [0035]      FIG. 4  is an illustration of the exemplary alternative embodiment of a hydraulic pressure reducer; 
           [0036]      FIG. 5  is an illustration of an exemplary alternative embodiment of a hydraulic pressure reducer; 
           [0037]      FIG. 6  is an illustration of an exemplary alternative embodiment of a hydraulic pressure reducer. 
       
    
    
     DETAILED DESCRIPTION 
       [0038]    Referring now to  FIG. 2 , an exemplary hydraulic trailer  22  is shown equipped with a hydraulic pressure reducer, or simply reducer  26 . The hydraulic pressure reducer  26  is coupled to a hydraulic system  28 . The hydraulic system  28  includes, the hydraulic piston cylinder assembly  14 , control valves  20  and quick coupler  24  as described above configured to couple the hydraulic system  28  of the hydraulic trailer  22  to the source of hydraulic pressure  16  on the tractor truck  12 . The hydraulic system  28  includes the control valves  20  one for each of the return line  30  and supply line  32  of the hydraulic system  28  The reducer  26  can be installed between the quick coupler  24  and the control valves  20  on either one of the hydraulic lines,  30 ,  32 . In a preferred embodiment, the reducer  26  is fluidly coupled to the return hydraulic line  30 , such that the hydraulic fluid can circulate normally in the hydraulic system  28 . 
         [0039]    Referring to  FIG. 3 , an exemplary hydraulic pressure reducer  26  is shown. The reducer  26  includes a body  34  including a first section  36  and second section  38  coupled to the first section  36 . The first section  36  and second section  38  can be bolted together in an exemplary embodiment. The first section  36  and second section  38  when coupled form a fluid reservoir  40 . The fluid reservoir  40  includes a diaphragm  42  that separates the reservoir  40  from an expansion region  44 . The expansion region  44  is shown proximate the second section  38 . The fluid reservoir  40  is configured to receive hydraulic fluid  46  from in the hydraulic line  30 . As the hydraulic fluid  46  expands in the hydraulic system  28 , the fluid reservoir  40  volume changes to accommodate the expansion. In the embodiment shown at  FIG. 3 , the diaphragm  42  flexes to change the fluid reservoir  40  volume. The reducer  26  includes a biasing element  48 . The biasing element  48  is configured to bias the diaphragm  42  allowing the diaphragm  42  to flex responsive to the pressure of the hydraulic fluid  46 . As the hydraulic fluid  46  increases pressure, the diaphragm  42  flexes and expands the volume of the fluid reservoir  40 . As the hydraulic fluid  46  decreases in pressure, the diaphragm  42  flexes and contracts the volume of the fluid reservoir  40 . The biasing element  48  exerts a force on the diaphragm  42  to contract the volume of the fluid reservoir  40 . As the fluid reservoir  40  expands with the diaphragm  42  in response to the increased hydraulic pressure, the biasing element  48  yields and changes position. 
         [0040]    In the embodiment shown in  FIG. 3 , the biasing element  48  includes a disc  50  coupled to a first end  52  of a rod  54  that extends through the second section  38  of the body  34 . A second end  56  of the rod  54  extends outside of the second section  38  and includes an adjustable member  58  configured to translate along the rod  54  to change the length of travel the rod  54  translates relative to the second section  38 . A spring  60  is coupled to the disc  50  and is configured to apply the force on the disc  50 . The disc  50  applies force on the diaphragm  42  opposite the hydraulic fluid pressure forces, shown as arrows  62  applied on the diaphragm in the opposite direction of the spring force. 
         [0041]    In operation the reducer  26  receives the hydraulic fluid  46  at a fluid coupling  64 , coupled to hydraulic line or simply, hose  30  of the hydraulic system  28  and fills the fluid reservoir  40 , expanding the volume. The fluid pressure  62  expands the diaphragm  42 . The biasing element  48  translates and retracts in response to the hydraulic fluid pressure  62 . The spring  60  changes position and increases in potential energy responsive to an increase in hydraulic fluid pressure. As the hydraulic fluid  46  pressure reduces the biasing element  48  presses the diaphragm  42  and contracts the reservoir  40  volume. The spring releases the potential energy and forces the diaphragm  42  against the decreasing hydraulic fluid pressure  62 . In practice, as the hydraulic fluid  46  increases pressure, for example due to thermal expansion, the reducer  26  expands hydraulic system volume to accommodate the increased pressure, thus minimizing the magnitude of the pressure in the hydraulic fluid  46 . 
         [0042]    In exemplary embodiment, shown at  FIG. 4 , the hydraulic pressure reducer  26  includes a body  34  with a coupling  64  coupled to a hydraulic line  30 . The biasing element  66  includes the flexible diaphragm  42  similar to the one shown at  FIG. 3 , except there is no spring, rod and disc assembly included. The biasing element  66  and a cushion of air at a given pressure along with the flexible diaphragm  42  and the material properties of the diaphragm  42  are relied on to apply resistive pressure to the hydraulic fluid  46 . The diaphragm  42  reacts to the change in hydraulic fluid pressure similarly to the reducer configuration described above. 
         [0043]    In exemplary embodiment, shown at  FIG. 5 , the hydraulic pressure reducer  26  includes a body  34  with a coupling  64  coupled to a hydraulic line  30 . The diaphragm is configured as a piston  70  in cylinder  72  configuration that is coupled to a spring  74  and is relied on to apply resistive pressure to the hydraulic fluid  46 . A set of seals  76 , typically an O-ring, is utilized to seal the piston and cylinder interface, preventing the hydraulic fluid  46  from leaking past the piston  70  along the cylinder  72  and piston  70  interface. The spring  74  provides the force that acts on the piston  70  and responds to the changes in hydraulic pressure  62 . 
         [0044]    In another exemplary embodiment, shown at  FIG. 6 , the hydraulic pressure reducer  26  includes a body  34  with a coupling  64  coupled to a hydraulic line  30 . The biasing element  78  includes a piston  80  in cylinder  82  configuration that is coupled to a spring  84  and is relied on to apply resistive pressure to the hydraulic fluid  46 . In this embodiment, the spring  84  includes two springs coupled to an exterior  86  of the body  34 . The springs  84  bias the piston  80  against the hydraulic forces  62 . A similar seal can be employed in this embodiment between the piston  80  and cylinder  82 . 
         [0045]    The hydraulic pressure reducer solves a longstanding problem of excessive hydraulic pressure in static hydraulic systems that have no hydraulic fluid reservoirs associated with the trailer or attachment. Every drop of hydraulic fluid that enters the hydraulic fluid system equals a drop of hydraulic fluid that exits the hydraulic system of the trailers or attachments. The reducer reduces pressure in static hydraulic system circuits, typically caused by thermal expansion of the hydraulic fluid due to temperature increases in the hydraulic fluid. The reducer is ideal for use with hydraulic trailers and other hydraulic equipment that are detachable from the hydraulic power source of the hydraulic system. The reducer enables easy reconnection of the hydraulic system at the quick connection couplers. The reducer functions well at low hydraulic pressures. The reducer prevents unwanted environmental degradation as it reduces the hydraulic fluid leaks that are associated with the over pressurization of the hydraulic fluid systems. The reducer automatically replaces the hydraulic fluid into the hydraulic system when the hydraulic system is re-connected at the quick connectors. The reducer also automatically resets to accommodate subsequent hydraulic system pressure changes. The reducer is configured to be employed in the hydraulic system and operate under full hydraulic pressure loads. The biasing element can be configured as a spring or as air pressure. 
         [0046]    There has been provided a hydraulic pressure reducer configured to prevent hydraulic over pressure in hydraulic trailers. While the reducer has been described in the context of specific embodiments thereof, other unforeseen alternatives, modifications, and variations may become apparent to those skilled in the art having read the foregoing description. Accordingly, it is intended to embrace those alternatives, modifications, and variations which fall within the broad scope of the appended claims.