Abstract:
The hydraulic pressure relief tool opens a check valve in the male portion of a hydraulic line coupler. The male portion has a locking ball receiving groove. The tool includes a male coupler holder and a coupler retainer that are pivotally connected together. The male coupler has a U-shaped groove. The sides of the groove slide in the ball receiving groove. The male coupler engaging surface on the retainer is moved across the U-shaped groove to lock the coupler to the tool. A fluid deflector housing covers a portion of the U-shaped groove. A check valve opener is mounted in a threaded passage in the housing. A valve engaging surface on the opener is advanced to open the check valve.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application claims the benefit of the filing date of U.S. Provisional Application No. 60/679,161, titled “HYDRAULIC COUPLER PRESSURE RELIEF TOOL” filed May 9, 2005. 

   TECHNICAL FIELD 
   The hydraulic pressure relief tool releases hydraulic pressure from a male hydraulic coupler component of a hydraulic quick coupler so that the male and female components of the hydraulic quick coupler can be coupled together. 
   BACKGROUND OF THE INVENTION 
   Hydraulic drive systems are employed on a variety of machines to perform various tasks. Many of the tasks require linear actuators or hydraulic motors. The linear actuators are often double acting and therefore require two hydraulic lines. The hydraulic motors all require a hydraulic fluid supply line and a hydraulic return line. 
   The machines that have hydraulic actuator systems have a pump driven by a power source and may have multiple attachments that are changed from time to time. To change from one attachment to another, hydraulic quick couplers have been developed. Hydraulic quick couplers generally include a male portion and a female portion. Both portions generally have check valves that close when they are disconnected. These check valves close to prevent the loss of hydraulic fluid and to reduce contamination of the hydraulic systems. Fine sand, dust, and liquid contaminants will cause serious damage to hydraulic systems and shorten their useful life. The check valves automatically close when the couplers are disconnected. Both check valves are open when the couplers are connected. 
   The male coupler portion of a hydraulic coupler is relatively easy to clean. The female coupler portion of a hydraulic coupler is somewhat more difficult to clean. Plugs can be used to help keep the female coupler portion clean when not in use. The general practice employed in most hydraulic systems is to attach the female coupler portion directly to a control valve. The control valve is connected to the pump that supplies hydraulic fluid under pressure and to a sump. The female coupler portion is generally in use when the pump is in use. The male coupler is generally connected to the actuator or motor on a device that is to receive and to be driven by hydraulic fluid. The male couplers occasionally sit for periods of time unused. 
   The male coupler portion is often connected to a closed system when it is disconnected from the female coupler portion. The closed system will contain some hydraulic fluid. The closed system may even be pressurized if there is an actuator in the system that is loaded. Hydraulic fluid is substantially uncompressable. However, the volume of most hydraulic fluids change with changes in temperature. A temperature increase of the hydraulic fluid in a closed system can increase the pressure to the point that the male coupler portion can not be manually connected to a female coupler portion. In order to couple the male coupler portion to a female coupler portion, some hydraulic fluid under pressure may have to be released from the closed system. If an actuator in the closed system is supporting a load, it can be necessary to drain a quantity of hydraulic fluid from the system. 
   During the release of hydraulic fluid under pressure from any hydraulic system, care must be taken to avoid contact with high velocity streams of fluid as well as hot fluids and cold fluids. Fluids release from a pressurized system can penetrate a person&#39;s skin, if moving at a high velocity, and cause injury. 
   SUMMARY OF THE INVENTION 
   The hydraulic coupler pressure relief tool includes a male coupler holder. The coupler holder has a holder end with a U-shaped slot. The slot has an open end, a pair of spaced apart side walls and a slot closed end. A hand holder end of the coupler holder has a hand grip surface. A pivot pin bore passes through the mail coupler holder between the U-shaped slot and the hand holder end. A coupler retainer includes a retainer bar end, a retainer hand holder end, a retainer hand grip on the retainer hand holder end and a male coupler engaging surface on the retainer bar end. The male coupler engaging surface on the retainer bar end faces toward the retainer hand holder end. A retainer pivot pin bore passes through the coupler retainer between the retainer bar end and the retainer hand holder end. A pivot pin passes through the retainer pivot pin bore and the pivot pin bore and pivotally connects the coupler retainer to the male coupler holder. A fluid deflector housing covers at least a portion of the U-shaped slot. A check valve opener includes a threaded shank that is received in a threaded bore through the fluid deflector housing. A handle for rotating the threaded shank is provided on one end of the threaded shank. A valve engaging surface on the threaded shank is movable toward the U-shaped slot by rotation of the threaded shank. 
   A male coupler passage into the fluid deflector housing permits a male hydraulic coupler slide into the U-shaped slot and into the fluid deflector housing. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects, features and advantages will become more readily apparent in view of the following detailed description and best mode, appended claims and accompanying drawings, in which: 
       FIG. 1  is a perspective view of the hydraulic coupler pressure relief tool being used; 
       FIG. 2  is a perspective view of the hydraulic coupler pressure relief tool; 
       FIG. 3  is a top plan view of the hydraulic coupler pressure relief tool; 
       FIG. 4  is an elevational view of the hydraulic coupler pressure relief tool; 
       FIG. 5  is an expanded view of the hydraulic coupler pressure relief tool; 
       FIG. 6A  is a sectional view showing a male hydraulic coupler portion held in the hydraulic coupler pressure relief tool prior to opening the check valve and with parts broken away; and 
       FIG. 6B  is a sectional view similar to  FIG. 6A  with the check valve open and with parts broken away. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A hydraulic coupler pressure release tool  10  is being used by a person  12  to release hydraulic fluid pressure from a flexible line  14  as shown in  FIG. 1 . The line  14  is connected to equipment mounted on the semi-trailer  16 . The equipment mounted on the trailer could be a floor conveyor for example. The engine in the tractor  18  drives a hydraulic fluid pump. After pressure is released from the flexible line  14 , a male coupler portion  20  on the free end of the line  14  will be attached to a female coupler portion (not shown) mounted on the tractor  18 . The female coupler portion is generally secured to the tractor  18  in a fixed position. In most hydraulic systems there is a second hydraulic line from the trailer that is connected to a second female coupler portion on the tractor  18 . The second hydraulic line may be a return line that returns hydraulic fluid to a sump. The line  14  may, in some hydraulic systems become a return line at times and the second hydraulic line can shift to a supply line. 
   Hydraulic fluid couplers are manufactured by a number of different companies. These couplers vary in construction and size to accommodate hydraulic systems with different maximum pressures and fluid flow rates. Only male hydraulic coupler portions  20  are described below. Various common constructions of the male coupler portion  20  will be described to the extent that the hydraulic coupler pressure release tool  10  is changed to accommodate different couplers. 
   The male coupler portion  20 , shown in  FIGS. 6A and 6B , include a cylindrical housing  22  with a distal end  24  and a proximal end  26 . The proximal end  26  is attached to the line  14  by a connector (not shown). Generally the proximal end  26  includes a threaded end that is attached to a threaded fitting on the line  14 . In some hydraulic systems the line  14  may be a rigid pipe with a threaded fitting on its free end. The distal end  24  positions the coupler portion  20  in an axial direction relative to a female coupler portion. A small diameter cylindrical outer surface  28  adjacent to the distal end  24 , radially positions the coupler portion  20  relative to the female coupler portion. A larger diameter cylindrical portion  30  of the coupler portion  20  positions a locking ball retainer sleeve of the female coupler portion radially relative to the coupler portion  20 . A locking ball receiving groove  32  is provided in the coupler portion  20  in a position axially spaced from the distal end  24  a selected distance. The large diameter cylindrical portion  30  is axially positioned adjacent to the groove  32  and between the distal end  24  and the groove. 
   The inside bore  34  of the male coupler portion  20  includes a valve seat  36 . A valve member  38  is housed in the bore  34  and is biased toward the valve seat  36  by a compression spring  40 . The valve member  38  includes a valve face  42  that contacts the valve seat  36  to prevent the flow of hydraulic fluid. The valve face  42 , as shown, carries a valve seal  44 . The seal  44  is a resilient o-ring as shown. The valve member  38  includes a guide stem  46  that keeps the valve member  38  coaxial with valve seat  36 . The valve member  38  also includes a valve control stem  48  that extends axially from the valve face  42  and toward the distal end  24  of the housing  22 . The inside bore  34  through the housing  22  includes a small diameter bore  50  that extends from the distal end  24  to the valve seat  36  and is coaxial with the valve control stem  48  and a large diameter bore  52  that extends from the valve seat  36  and away from the small diameter bore  50 . 
   The valve control stem  48  engages a female valve control stem in a female coupler portion during use and the valve member  38  and a valve in the female coupler are both opened. When both valves are open, the male coupler portion  20  and a female coupler portion are coupled together. With the free end  54  of the valve control stem  48  between the valve seat  36  and the distal end  24  of the cylindrical housing  22  when the valve face  42  is adjacent to the valve seat  36 , as shown in  FIG. 6A , the valve control stem in the female coupler portion must be lengthened somewhat. Some hydraulic couplers have the free end  54  of the valve control stem  48  extending out of the small diameter bore  50  when the valve member  38  is closed. With the longer valve control stem  48 , the length of the valve control stem in the female coupler portion must be shortened somewhat. 
   The check valves in some hydraulic fluid couplers are ball check valves. With these valves the valve seat joins the distal end of the housing and the small diameter bore  50  is eliminated. The ball of a ball check valve protrudes from the housing  22  a short distance when the valve is closed. Ball check valves generally have a decreased fluid flow rating compared to couplers with the valve member  38  described above. 
   The hydraulic coupler pressure release tool  10  includes a male coupler holder  60  with a U-shaped slot  62  on a male coupler portion holder end  64 . A hand grip  66  is provided on a hand hold end  68  of the male coupler holder  60 . A holder pivot pin bore  70  through the male coupler holder  60  is between the male coupler portion holder end  64  and the hand hold end  68 . The U-shaped slot  62  has parallel side walls  72  and  74  that are spaced apart a distance that is slightly more than the diameter of the base of the locking ball receiving groove  32  in the cylindrical housing  22 . The closed end  76  is an arcuate surface with a radius that is half the distance between the side walls  72  and  74  of the U-shaped slot  62 . Three fluid shield housing anchor passages  78  pass through the male coupler holder  60  adjacent to the U-shaped passage  62 . A small diameter bore  80  is drilled through a free end of the hand holder end  68   
   A coupler retainer  82 , of the hydraulic coupler pressure release tool  10 , includes a retainer bar end  84  and a retainer hand holder end  86 . The hand holder end  86  includes a hand grip  88 . A retainer pivot pin bore  90  passes through the coupler retainer  82  between the retainer bar end  84  and the hand holder end  86 . A male coupler engaging surface  92  on the retainer bar end  84  faces toward the retainer pivot pin bore  90 . The portion of the male coupler engaging surface  92  that retains a male coupler portion is nearly tangential to a circle that is coaxial with retainer pivot pin bore  90 . A small diameter bore  94  is drilled through a free end of the retainer hand holder end  86 . 
   A pivot bolt  96  passes through the retainer pivot pin bore  90  and the holder pivot pin bore  70  and screws into a nut  98 . The nut  98  is preferably a locking nut and permits the male coupler holder  60  and the coupler retainer  82  to pivot freely relative to each other. 
   A short chain  100  has one end anchored in the small diameter bore  80  in the hand holder end  68 . The other end of the short chain  100  is anchored in the small diameter bore  94  through the retainer hand holder end  86 . The short chain  100  limits pivotal movement of the retainer bar end  84  away from the U-shaped slot  62 . The chain  100  is also used for hanging the hydraulic coupler pressure release tool  10  on a hook or pin member when not in use. 
   A fluid deflector housing  102  includes a deflector wall  104  and a fluid deflector top  106 . The deflector wall  104  has an arcuate center section  108  and spaced apart parallel end sections  110  and  112 . A lower edge  114  of the housing  105  seats on the surface  118  of the male coupler holder  60 . Tongues  116  extend downward from the lower edge  114  and pass through the anchor passages  78  through the holder  60 . The tongues  116  are fixed to the holder  60  by welding or other suitable anchoring system. The deflector top  106  has an upper wall section  120  that is parallel to the surface  118  of the male coupler holder  60 . An inclined upper wall section  122  extends from upper wall section  120 , toward the surface  118  and ends at a lower free edge  142 . 
   A bore  124  is provided through the upper wall section  120 . A threaded nut  126  is welded to an inside or bottom surface of the deflector top  106  in a position coaxial with the bore  124 . A check valve opener  128  includes a threaded shank  130  that screws through the nut  126 . An end  132  integral with the inside end of the threaded shank  130  has a valve engaging surface  134  that faces away from the threaded shank  130 . The shape and size of the end  132  with the valve engaging surface  134  is changed as required to accommodate the check vale that is to be opened. A wing  140  is fixed to the end of the threaded shank  130  opposite the end  132 . The wing  140  is turned to advance and to retract the valve engaging surface  134 . If necessary, a fluid passage can be provided through the end  132 . 
   During use of the hydraulic coupler pressure release tool  10 , the locking ball receiving groove  32  is received in the U-shaped slot  62 . The distal end  24  of the male hydraulic coupler portion  20  passes between the surface  118  of the male coupler holder  60  and the edge  142  of the inclined upper wall section  122 . Moving the hand holder end  68  toward the retainer hand holder end  86  moves the retainer bar end  84  through a slot between the surface  118  and the edge  144  and moves the male coupler engaging surface  92  into engagement with the cylindrical male coupler housing  22 . The male coupler engaging surface  92  engages the locking ball receiving groove as shown in  FIGS. 6A and 6B . The coupler engaging surface  92  may engage the cylindrical portion  30  of the cylindrical housing. The wing  140  is rotated to move the valve engaging surface  134  into engagement with the free end  54  of the check valve member  38 , open the valve and reduce the fluid pressure in the line  14 . Hydraulic fluid that is discharged can be directed in to an open container. After the fluid pressure is reduced, the wing  140  and the shank  130  are rotated to withdraw the valve engaging surface  134  from engagement with the valve member  38 . The male coupler engaging surface  92  is then pivoted about the axis of the pivot pin or pivot bolt  96  to with draw the retainer bar end  84  from the fluid deflector housing  102  and the male coupler portion  20  is removed from the U-shaped slot  62 .