Dispensing tool assembly for charging a refrigerant into a system

Abstract

A tubular body supports a fluid actuated tubular piston connected to operate a coupling mechanism for releasably securing the body to a valve fitting on a refrigerant receiving system. The body encloses components which define a center passage connected to the fitting for first evacuating air from the system and then for directing liquid refrigerant into the system. The passage receives an elongated valve opening member which is fluid actuated to a position opening the valve fitting, and a movable valve member closes the passage to the flow of refrigerant. The fluid actuated coupling mechanism provides for convenient and simple insertion of the tool assembly onto the fitting with no insertion force and also for automatic release of the tool assembly from the fitting after charging is completed. A fluid actuated valve member minimizes the volume of residue refrigerant which vaporizes when the tool assembly is removed from the fitting.

The invention having thus been described, the following is claimed: 
     
       1. A dispensing tool assembly for connecting a refrigerant charging unit to a refrigerant receiving system having a tubular fitting with an internal movable valve element, said tool assembly comprising a tubular body having a center axis, means supported within said body and defining an axially extending fluid passage, means for selectively connecting a suction line and a refrigerant supply line to said passage, means forming a fluid-tight seal between said means defining said passage and the fitting, an elongated valve element opening member disposed within said passage for axial movement, first fluid actuating means for moving said valve element opening member between a retracted position and an extended position where the valve element within the fitting is moved to an open position, coupling means supported by said body for movement between a released position and a locked position positively connecting said body to the fitting, a piston supported by said body for axial movement between an extended position and a retracted position, means connecting said piston to said coupling means for moving said coupling means to said locked position in response to the application of a pressurized fluid to move said piston to said extended position means for moving said piston to said retracted position for moving said coupling means to said released position to provide for convenient coupling of said tool assembly to the fitting and automatic release of said tool assembly from the fitting after the receiving system has received a predetermined charge of refrigerant, a valve member supported within said means defining said fluid passage within said body, said valve member being movable between an open position allowing refrigerant to flow through said passage and a closed position, .[.and.]. fluid actuated means for moving said valve member between said open and closed positions.Iadd., and means for removing substantially all of the refrigerant within said fluid passage between said valve member and the fitting before removing said tool assembly from the fitting to prevent the refrigerant from escaping into the air surrounding said tool assembly.Iaddend.. 
     
     
       2. A tool assembly as defined in claim 1 wherein said piston is tubular and has an axis common with the center axis of said body, said coupling means including a plurality of circumferentially spaced movable gripping elements and supported to engage a shoulder on the tubular fitting, and means connecting said tubular piston to said gripping elements for moving said gripping elements into engagement with the fitting in response to movement of said tubular piston to said extended position. 
     
     
       3. A tool assembly as defined in claim 2 wherein said means for moving said piston to said retracted position comprise a compression spring for normally positioning said gripping elements of said coupling means in said released position to provide for inserting said tool assembly onto the fitting with minimal force. 
     
     
       4. A tool assembly as defined in claim 3 wherein said coupling means further include a support member supporting said gripping elements for relative movement, and said support member defines a tapering cavity for receiving the fitting to facilitate insertion of the tool assembly onto the fitting without requiring precise alignment between the fitting and said tool assembly. 
     
     
       5. A tool assembly as defined in claim 1 wherein said piston is tubular and surrounds said tubular body. 
     
     
       6. A tool assembly as defined in claim 1 wherein said means forming a fluid-tight seal comprise a resilient sealing ring surrounding said passage, and means supported by said body and retaining said sealing ring. 
     
     
       7. A tool assembly as defined in claim 1 wherein said valve member surrounds said valve element opening member and is movable axially thereon, resilient sealing means engaging said valve member and cooperating therewith to form a valve for controlling the flow of fluid within said passage, and fluid actuated means for moving said valve member on said valve element opening member. 
     
     
       8. A tool assembly as defined in claim 7 wherein said valve member is movable on said valve element opening member to a position adjacent said means forming a fluid-tight seal for minimizing the escape of refrigerant gas from said tool assembly after being removed from the fitting. 
     
     
       9. A dispensing tool assembly for connecting a refrigerant charging unit to a refrigerant receiving system having a tubular fitting with an internal movable valve element, said tool assembly comprising a tubular body having a center axis, means supported within said body and defining an axially extending fluid passage, means for selectively connecting a suction line and a refrigerant supply line to said passage, means forming a fluid-tight seal between said means defining said passage and the fitting, an elongated tubular valve member disposed within said passage for axial movement, an elongated valve element opening member disposed within said valve member for axial movement, first fluid actuating means for moving said valve element opening member between a retracted position and an extended position where the valve element within the fitting is moved to an open position, second fluid actuated means for moving said valve member on said valve element opening member to control the flow of fluid through said passage, coupling means supported by said body for movement between a released position and a locked position positively connecting said body to the fitting, a tubular piston supported by said body for axial movement between an extended position and a retracted position, means connecting said piston to said coupling means for moving said coupling means to said locked position in response to the application of a pressurized fluid to move said piston to said extended position, and means for moving said piston to said retracted position for moving said coupling means to said released position to provide for convenient coupling of said tool assembly to the fitting and automatic release of said tool assembly from the fitting after the receiving system has received a predetermined charge of refrigerant. 
     
     
       10. A tool assembly as defined in claim 9 wherein said coupling means include a plurality of circumferentially spaced gripping elements pivotally supported to engage a shoulder on the tubular fitting, and means connecting said tubular piston to said gripping elements for pivoting said gripping elements into engagement with the fitting in response to movement of said piston to said extended position. 
     
     
       11. A tool assembly as defined in claim 9 wherein said means for moving said piston to said retracted position comprise compression spring means for normally positioning said gripping elements of said coupling means in said released position to provide for inserting said tool assembly onto the fitting with minimal force. 
     
     
       12. A tool assembly as defined in claim 10 wherein said coupling means further include a support member supporting said gripping elements for said pivotal movement, and said support member defines a tapering cavity for receiving the fitting to facilitate insertion of the tool assembly onto the fitting without requiring precise alignment between the fitting and said tool assembly. 
     
     
       13. A tool assembly as defined in claim 9 and including an annular valve member surrounding said passage within said body, said valve member being movable between an open position allowing refrigerant to flow through said passage and a closed position, spring means urging said annular valve member to said closed position, and said annular valve member being movable to said open position in response to the pressure of the refrigerant. 
     
     
       14. A tool assembly as defined in claim 9 wherein said piston is tubular and surrounds said tubular body. 
     
     
       15. A tool assembly as defined in claim 9 and including a second piston supported within said body for moving said valve member, and means defining passages for directing fluid to move said piston and said valve member in both axial directions. 
     
     
       16. A tool assembly as defined in claim 9 wherein said tubular valve member is movable on said valve element opening member to a position adjacent said means forming a fluid-tight seal for minimizing the volume of refrigerant gas within said passage before said tool assembly is removed from the fitting. 
     
     
       17. A method of charging a liquid refrigerant into a refrigerant receiving system having a fitting with an internal valve element and with the use of a dispensing tool assembly having means defining an internal charging passage, comprising the steps of moving the tool assembly onto the fitting with the fitting in alignment with the charging passage, coupling the tool assembly to the fitting by moving a first fluid actuated piston forming part of the tool assembly, forming a fluid-tight seal between the fitting and the means defining the charging passage, opening the internal valve element within the fitting by moving an actuating member axially with a second fluid actuated piston within the tool assembly, connecting the charging passage to a suction line to evacuate air from the system through the fitting and the charging passage, connecting the charging passage to a refrigerant supply line to provide for charging liquid refrigerant into the system through the fitting, closing the passage by moving a valve member within the passage, closing the valve element within the fitting by moving the actuating member axially with the second fluid actuated piston, .Iadd.removing substantially all of the liquid refrigerant within the charging passage between the valve member and the fitting before removing the tool assembly from the fitting to prevent the refrigerant from escaping into the air surrounding the tool assembly, .Iaddend.and decoupling the tool assembly from the fitting by moving the first actuated piston. 
     
     
       18. A method of charging a liquid refrigerant into a refrigerant receiving system having a fitting with an internal valve element and with the use of a dispensing tool assembly having means defining an internal charging passage, comprising the steps of moving the tool assembly onto the fitting with the fitting in alignment with the charging passage, coupling the tool assembly to the fitting by moving a fluid actuated piston forming part of the tool assembly, forming a fluid-tight seal between the fitting and the means defining the charging passage, opening the internal valve element within the fitting by moving an actuating member axially within the tool assembly, connecting the charging passage to a suction passage within the tool assembly to evacuate air from the system through the fitting and the charging passage, closing the suction passage within the tool assembly by moving a first valve member within the tool assembly, connecting the charging passage to a refrigerant supply passage by moving a second valve member within the tool assembly to provide for charging liquid refrigerant into the system through the fitting, closing the refrigerant supply passage by moving the second valve member within the tool assembly, displacing the liquid refrigerant within the charging passage by moving a member within the charging passage, closing the valve element within the fitting by moving the actuating member axially within the tool assembly, and decoupling the tool assembly from the fitting by moving the piston. 
     
     
       19. A dispensing tool assembly for connecting a liquid charging unit to a liquid receiving system having a tubular fitting with an internal movable valve element, said tool assembly comprising a tubular body having a center axis, means supported within said body and defining an axially extending fluid passage, means for selectively connecting a suction line and a liquid supply line to said passage, means forming a fluid-tight seal between said means defining said passage and the fitting, an elongated valve element opening member disposed within said passage for axial movement, first fluid actuating means for moving said valve element opening member between a retracted position and an extended position where the valve element within the fitting is moved to an open position, coupling means supported by said body for movement between a released position and a locked position positively connecting said body to the fitting, a piston supported by said body for axial movement between an extended position and a retracted position means connecting said piston to said coupling means for moving said coupling means to said locked position in response to the application of a pressurized fluid to move said piston to said extended position, means for moving said piston to said retracted position for moving said coupling means to said released position to provide for convenient coupling of said tool assembly to the fitting and automatic release of said tool assembly from the fitting after the receiving system has received a predetermined charge of liquid, a valve member supported within said means defining said fluid passage within said body, said valve member being movable between an open position allowing liquid to flow through said passage and a closed position, .[.and.]. fluid actuated means for moving said valve member between said open and closed positions.Iadd., and means for removing substantially all of the liquid within said fluid passage between said valve member and the fitting before removing said tool assembly from the fitting to prevent the liquid from escaping into the air surrounding said tool assembly.Iaddend..