Abstract:
A latch bracket for attachment to a hydraulically operated tool having a hydraulic mechanism, the latch bracket includes a first fluid channel extending therethrough, with a first port coupled to the first fluid channel for coupling the first fluid channel to the hydraulic mechanism. The latch bracket receives a male latch pin on a tool coupler to lock the tool to the tool coupler and to couple the first fluid channel to a source of hydraulic pressure through the latch pin.

Description:
This is a divisional application of U.S. application Ser. No. 09/124,637, filed Jul. 29, 1998, the entire disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to fluid connectors, and, in particular, to a multi-line hydraulic connector adapted for se in a tool coupler used with excavation, demolition and construction equipment. 
     Some types of construction equipment, such as backhoes or excavators, include a movable dipper stick (also referred to as an arm) to which a variety of tools, such as buckets, grapples, hammers and the like, can be attached. A hydraulic bucket cylinder coupled to the attached tool at a link pivot rotates the tool about a dipper pivot at the free end of the dipper stick. The bucket cylinder and a linkage to the link pivot are located on a distal (forward) side of the dipper stick relative to the cab where the operator sits. To simplify the process of changing tools, a tool coupler can be permanently attached to the dipper pivot and the link pivot. A selected tool can then be removably attached to the coupler with a locking mechanism. The locking mechanism, in some cases, includes a locking pin on the tool coupler that engages a mating receptacle in the tool. 
     There is a trend in the industry to use an actuated quick-disconnect tool coupler for automatically connecting and disconnecting a tool. Co-owned U.S. Pat. No. 5,727,342, to Horton, describes a quick-disconnect tool coupler that includes a latch pin biased by a spring to a forward locking position. The latch pin is retracted by extending a hydraulic latch pin cylinder located in the coupler. With this type of tool coupler, the equipment operator can switch tools without leaving the cab of the equipment. 
     Some tools include a hydraulically actuated mechanism. For example, some grapple attachments include a hydraulic cylinder for opening and closing the grapple jaws. The tool hydraulics typically require two hydraulic connections between the tool hydraulics and hydraulic lines extending to the end of the dipper stick. In presently available systems, these connections must be made manually. This reduces the efficiencies of the hydraulically actuated quick-disconnect tool coupler systems, because the equipment operator must leave the cab to make the connections or a second worker must be available to do so. 
     SUMMARY OF THE INVENTION 
     The invention features a non-spill, multi-line fluid connector with a plurality of separate, substantially coaxial flow paths. The fluid connector can be incorporated into a latch pin assembly of a quick-connect tool coupler. 
     The connector design does not compromise the latching mechanism of the quick coupler. The latching mechanism includes a latch pin in the tool coupler and a latch bracket that receives the latch pin in the tool. The latch pin is spring applied, and hydraulically released from the latch bracket. Each of the latch pin and latch bracket includes longitudinally movable internal parts that provide a pair of coaxial fluid channels. These parts cooperate when the latch pin is inserted into the latch bracket to provide connections between the pairs of channels. The invention allows tools and existing couplers to be easily converted to the new system. An equipment operator can connect a hydraulically actuated tool to the tool coupler, including all hydraulic connections, without leaving the cab of the equipment. The fluid connector includes a locking mechanism that enhances the overall safety of the equipment by inhibiting accidental release of the hydraulic tool when pressure is hydraulic pressure is applied to hydraulic actuator in the tool. 
     According to one aspect of the invention, a fluid connector includes a first part having a distal end and a second part having a proximal end adapted to be removably connected to the distal end of the first part. The first part includes first and second fluid channels extending within the first part from respective first and second end seals at the distal end and couple to respective first and second fluid ports. The end seals close off the first and second fluid channels when the first part is disconnected from the second part. The second part includes first and second fluid channels extending within the second part from respective first and second end seals at the proximal end and couple to respective first and second fluid ports. The end seals of the second part close off the first and second fluid channels of the second part when the first part is disconnected from the second part. Connecting the first part to the second part connects the first fluid channels of the first and second parts and also connects the second fluid channels of the first and second parts. 
     The first and second fluid channels of one or both of the first part and the second part can be arranged concentrically. With this feature, the first and second parts are cooperatively structured to permit the first and second parts to rotate relative to each other while connected together. In one embodiment, the second fluid channel of the first part includes an outer channel arranged concentrically around the inner, first channel of the first part, and the second fluid channel of the second part includes an outer channel arranged concentrically around the inner channel of the second part. The inner channel of the first part can be a central channel arranged on a central axis of the first part. 
     The first and second parts can be adapted to connect together with make-before-break seals such that the first end seal of one of the first and second parts establishes a seal with the other of the first and second parts before the first end seal of the other of the first and second parts opens, and such that the second end seal of the one of the first and second parts establishes a seal with the other of the first and second parts before the second end seal of the other of the first and second parts opens. 
     The first part can be constructed to include the following features: An elongated pin body has a central bore extending from the distal end to near a proximal end, and a pin head at the proximal end of the pin body. The pin head includes the first and second ports of the first part, wherein first and second connecting channels communicate between the first and second ports, respectively and the central bore. The bore has a pin central opening surface, which includes, at a distal end, a cylindrical distal portion and a tapered portion sloping radially inward toward the cylindrical distal portion, and which also includes, at a proximal end, a cylindrical proximal portion having a smaller diameter than the cylindrical distal portion of the pin central opening surface. The cylindrical distal portion and the tapered portion of the pin central opening surface can be on a pin outer sleeve that is substantially fixed in position at a distal end of the pin body. The first part also includes a tube having a proximal outer surface positioned adjacent the cylindrical proximal portion of the pin central opening surface. The tube is positioned such that it divides between the central channel and the outer channel. The first connecting channel communicates with the central channel and the second connecting channel communicates with the outer channel. A pin proximal seal is arranged to provide a seal between the proximal outer surface of the tube and the cylindrical proximal portion of the pin central opening surface. A pin inner sleeve includes a cylindrical surface at a proximal end adapted to slide along a cylindrical surface at a distal end of the tube. An outer surface of the pin inner sleeve has a cylindrical distal portion adapted to slide along the cylindrical distal portion of the pin central opening surface, and a tapered portion adapted to fit against the tapered portion of the pin central opening surface. An inner surface of the pin inner sleeve has a cylindrical distal portion and a tapered portion sloping radially inward toward the cylindrical distal portion of the inner surface of the pin inner sleeve. The second end seal of the first part includes a seal located between the cylindrical distal portion of the outer surface of the pin inner sleeve and the cylindrical distal portion of pin central opening surface. A pin outer bias member is arranged to urge the tapered portion of the outer surface of the pin inner sleeve against the tapered portion of the pin central opening surface. A pin middle seal is arranged to provide a seal between the cylindrical surface at the proximal end of the pin inner sleeve and the cylindrical surface at the distal end of the tube. A plug has a cylindrical distal surface adapted to slide along the cylindrical distal portion of the inner surface of the pin inner sleeve, and a tapered surface adapted to fit against the tapered portion of the inner surface of the pin inner sleeve. The first end seal of the first part is located between the cylindrical distal surface of the plug and the cylindrical distal portion of the inner surface of the pin inner sleeve. A pin inner bias member is arranged to urge the tapered portion of the outer surface of the plug against the tapered portion of the inner surface of the pin inner sleeve. Thus, in this arrangement of the first part, the central channel is defined by an inner surface of the tube, the inner surface of the pin inner sleeve, the plug, and the first end seal of the first part. The outer channel of the first part is defined by the pin central opening surface, the outer surface of the tube the outer surface of the pin inner sleeve, and the second end seal. The pin proximal seal and the pin middle seal provide seals between the central channel and the outer channel. 
     The second part can include one or more of the following additional features. An elongated plunger extends proximally from a bracket body a first distance and has an outwardly sloped surface near a proximal end. A substantially annular inner section member extends proximally from the bracket body a second distance that is less than the first distance. The inner section member is arranged substantially concentrically around the plunger and includes a cylindrical surface. A substantially annular outer section member extends proximally from the bracket body a third distance that is less than the first distance and greater than the second distance. The outer section member is arranged concentrically around the inner section member and includes a cylindrical surface. A bracket inner sleeve has an inner surface with an outwardly sloped portion at a proximal end adapted to fit against the outwardly sloped surface of the plunger. The bracket inner sleeve also has an outer surface with an outwardly sloped portion near a distal end, and a cylindrical surface at a distal end that slidingly engages with the cylindrical surface of the inner section member. The end seal of the inner channel of the second part is provided between the outwardly sloped portion of the inner surface of the bracket inner sleeve and the outwardly sloped surface of the plunger. The inner channel of the second part, which is substantially annular shape, is defined by the plunger, an inner surface of the inner section member and the inner surface of the inner sleeve. A bracket inner middle seal is arranged to seal between the cylindrical surface of the inner section member and the cylindrical surface of the bracket inner sleeve. A bracket second sleeve has an inner surface having an outwardly sloped portion at a proximal end adapted to fit against the outwardly sloped surface of the outer surface of the inner sleeve, and a cylindrical surface at a distal end that slidingly engages with the cylindrical surface of the inner section member. The end seal of the outer channel of the second part is provided between the outwardly sloped portion of the inner surface of the bracket second sleeve and the outwardly sloped surface of the outer surface of the bracket inner sleeve. The outer channel of the second part is defined by an outer surface of the inner section member, an outer surface of the bracket inner sleeve, the inner surface of the bracket second sleeve, and an inner surface of the outer section member. The bracket inner middle seal seals between the inner channel and the outer channel of the first part. A bracket outer middle seal is arranged to seal between the cylindrical surface of the outer section member and the cylindrical surface of the bracket second sleeve. A bracket bias member is arranged to urge the bracket second sleeve proximally against the bracket inner sleeve and the bracket inner sleeve against the plunger. 
     In addition, the bracket body can further include a cylindrical bearing at a proximal end adapted to receive the pin body such a distal face of the plug first contacts a proximal face of the plunger when the pin body moves distally through the cylindrical bearing. The outer surface of the bracket inner sleeve can also include, at its proximal end, a cylindrical proximal portion that is approximately the same diameter as the cylindrical surface of the plug. Thus, upon further movement of the pin body through the cylindrical bearing in the distal direction, the plug is prevented from further distal movement, the cylindrical distal portion of the inner surface of the pin inner sleeve slides over the cylindrical proximal portion of the outer surface of the bracket inner sleeve, and a gap opens between the inwardly sloped surface of the plug and the inwardly sloped portion of the inner surface of the pin inner sleeve. The first end seal of the first part may include an inner distal o-ring that slides with the pin inner sleeve over the cylindrical proximal portion of the outer surface of the bracket inner sleeve. 
     An outer surface of the bracket second sleeve can have, at a proximal end thereof, a cylindrical proximal portion approximately the same diameter as the cylindrical distal portion of the pin central opening surface. With this arrangement, upon yet further movement of the pin body through the cylindrical bearing in the distal direction, a distal facing surface of the pin inner sleeve stops against a proximal facing portion of the outer surface of the bracket inner sleeve, the cylindrical distal portion of the pin central opening surface slides over the cylindrical proximal portion of the outer surface of the bracket second sleeve, and a gap opens between inwardly sloped portions of the pin central opening surface and the outer surface of the pin inner sleeve. The second end seal of the first part includes an outer distal o-ring that slides with the pin body over the cylindrical proximal portion of the outer surface of the bracket second sleeve. The pin inner bias member, the pin outer bias member, and the bracket bias member can be selected such that the first and second end seals of the second part remain sealed, such that the central channel and outer channel of the first part remain closed, and such that the inner channel and the outer channel of the second part remain closed, as the outer distal o-ring slides over the cylindrical proximal portion of the outer surface of the bracket second sleeve. Upon yet more distal movement of the pin body through the cylindrical bearing, a distal end of the pin body contacts a proximal facing portion of an outer surface of the bracket second sleeve, and pushes the bracket second sleeve and the bracket inner sleeve together distally such that the bracket inner sleeve slides distally away from the outwardly sloped surface of the plunger. This opens the first end seal of the second part and connects the inner channel of the second part to the central channel of the first part, until the distal end of the bracket inner sleeve reaches a proximal facing stop surface that prevents further distal movement of the pin inner sleeve while the bracket second sleeve continues to move distally. The continued distal movement of the bracket second sleeve opens the second end seal of the second part and connects the outer channel of the second part to the outer channel of the first part. 
     In other features, the second part may further include a locking mechanism that inhibits the pin body from moving away from the second part while fluid pressure is applied through the first part and the second part. The first part can include a fluid switch arranged to turn on to weakly couple fluid pressure in the central channel with fluid pressure in the outer channel when the first part is disconnected from the second part, and to turn off to decouple fluid pressure in the central channel with fluid pressure in the outer channel when the first part is connected to the second part. The second part may also include a fluid switch arranged to turn on to weakly couple fluid pressure in the inner channel with fluid pressure in the outer channel when the first part is disconnected from the second part, and to turn off to decouple fluid pressure in the inner channel with fluid pressure in the outer channel when the first part is connected to the second part. The second part can have a distal end cap, which includes the first and second ports of the second part, a first connecting channel communicating between the first port and the inner channel of the second part, and a second connecting channel communicating between the second port and the outer channel of the second part. The second part may also have a backing piece, which includes the inner section member, the outer section member and an opening there-between. The backing piece is capable of moving a small lateral distance from a central axis of the second part. 
     In another aspect, the invention provides a latch member, such as a latch pin, for a tool coupler, adapted to engage with a latch receptacle, such as a latch bracket, on a tool to lock the tool to the tool coupler. The latch member may include one or a plurality of fluid channels. The plurality of fluid channels can include first and second fluid channels, extending through the latch member for providing a corresponding plurality of fluid connections to the tool through the latch receptacle. The second fluid channel can be an outer fluid channel concentrically surrounding the first fluid channel, and the first fluid channel can be a central fluid channel extending along a central axis of the latch member. A first distal o-ring provides a seal at a distal end of the central channel and a second distal o-ring provides a seal at a distal end of the outer channel when the latch member is disconnected from the latch receptacle. The first and second distal o-rings are located near a distal end of the latch member that connects to the latch receptacle. 
     An embodiment of the latch pin is adapted to slidingly engage with the latch bracket. The latch pin can further include an elongated pin body that has a central opening extending from a distal end of the latch pin to a proximal end of the latch pin. The central opening has a central opening surface, which includes, at a distal end, a cylindrical distal portion and a tapered portion sloping radially inward toward the cylindrical distal portion, and which also includes, at a proximal end, a cylindrical proximal portion having a smaller diameter than the cylindrical distal portion of the pin central opening surface. The cylindrical distal portion of the central opening surface includes an o-ring groove in which the second distal o-ring is positioned. The cylindrical distal portion and the tapered portion of the pin central opening surface can be part of an outer sleeve substantially fixed in position at a distal end of the pin body. A tube divides between the central channel and the outer channel. The tube includes an outer surface having a proximal portion positioned adjacent the cylindrical proximal portion of the pin central opening surface. A proximal o-ring seals between the proximal portion of the tube outer surface and the cylindrical proximal portion of the pin central opening surface. A first hydraulic fluid port couples to the central channel on a proximal side of the proximal o-ring, and a second hydraulic fluid port couples to the outer fluid channel on a distal side of the proximal o-ring. An inner sleeve includes, at a proximal end of an inner surface, a cylindrical surface that is adapted to slide along a cylindrical surface at a distal end of the tube, which cylindrical surface can be on the outer surface of the tube. The inner sleeve also has an outer surface, which includes a cylindrical distal portion adapted to slide along the cylindrical distal portion of the pin central opening surface. The second distal o-ring provides a seal therebetween. The outer surface of the inner sleeve has a tapered portion adapted to fit against the tapered portion of the pin central opening surface. The inner sleeve has an inner surface that includes a cylindrical distal portion and a tapered portion sloping radially inward toward the cylindrical distal portion of the inner surface of pin inner sleeve. The cylindrical distal portion of the inner sleeve inner surface includes an o-ring groove in which the first distal o-ring is positioned. An outer bias member is arranged to urge the tapered portion of the outer surface of the pin inner sleeve against the tapered portion of the pin central opening surface. A middle o-ring is arranged to provide a seal between the cylindrical surface at the proximal end of the pin inner sleeve and the cylindrical surface at the distal end of the tube. An plug includes a cylindrical distal surface adapted to slide along the cylindrical distal portion of the inner surface of the pin inner sleeve. The first distal o-ring provides a seal therebetween. The plug also has a tapered surface adapted to fit against the tapered portion of the inner surface of the pin inner sleeve. An inner bias member is arranged to urge the tapered portion of the outer surface of the plug against the tapered portion of the inner surface of the pin inner sleeve. In this structure, the central channel is defined by an inner surface of the tube, the inner surface of the pin inner sleeve, the plug, and the first distal o-ring. The outer channel is defined by the pin central opening surface, the outer surface of the tube, the outer surface of the pin inner sleeve, and the second distal o-ring. The proximal o-ring and the middle o-ring seal between the central channel and the outer channel. 
     The inner bias member can be an inner coil spring positioned between a proximal facing shoulder of an inner surface of the tube and a proximal facing end of the plug. The outer bias member can be an outer coil spring positioned between a proximal facing shoulder formed on the central opening surface and a distal facing shoulder formed on the outer surface of the inner sleeve. 
     The latch member can further include a fluid switch between the central channel and the outer channel that is closed circuit when the latch member is disconnected from the latch receptacle to equalize pressures between the central channel and the outer channel, and that is open circuit when the latch member is connected to the latch bracket to allow for a pressure difference between the central channel and the outer channel. The fluid switch can include a small aperture in the inner sleeve that is located on a distal side of the middle o-ring when the switch is closed circuit and that is positioned on a proximal side of the middle o-ring when the switch is open circuit. 
     The latch member can be in combination with the tool coupler. The tool coupler includes a hydraulic latch member actuating mechanism adapted to move the latch member under hydraulic control between a position locked with the latch receptacle and a position unlocked from the latch receptacle. The hydraulic latch member actuating mechanism can include a spring arranged to urge the latch member into the locked position and a hydraulic cylinder having an extendable rod arranged to urge the latch member toward the unlocked position when the rod is extended. 
     In yet another aspect, the invention provides a latch bracket for attachment to a hydraulically operated tool having a hydraulic mechanism. The latch bracket includes at least a first, and may include a second, fluid channel extending therethrough. The latch bracket is adapted to receive a male latch pin on a tool coupler to lock the tool to the tool coupler and to couple the fluid channels to sources of hydraulic pressure through the latch pin. First and second ports are coupled to the first and second fluid channels, respectively, for coupling the fluid channels to the hydraulic mechanism. The second fluid channel can be an outer fluid channel concentrically surrounding the first fluid channel, and the first fluid channel can be a substantially annular inner fluid channel. An inner proximal o-ring provides a seal at a proximal end of the inner channel and an outer proximal o-ring provides a seal at a proximal end of the outer channel when the latch pin is disconnected from the latch bracket. The first and second proximal o-rings are arranged to unseal when the latch pin connects to the latch bracket. 
     The latch bracket can include the following additional features. A latch bracket body has a cylindrical bearing at a proximal end adapted to receive and guide the latch pin, and an end cap at a distal end. An elongated plunger extends proximally from the body a first distance. The plunger includes an outwardly sloped surface near a proximal end, and a proximal end face that first contacts a distal end of the latch pin when the latch pin is inserted into the cylindrical bearing. The outwardly sloped surface has an o-ring groove in which the inner proximal o-ring is positioned. A substantially annular inner section member extends proximally from the body a second distance that is less than the first distance. The inner section member includes a cylindrical surface and is arranged substantially concentrically around the plunger, providing a gap therebetween. A substantially annular outer section member extends proximally from the body a third distance that is less than the first distance and greater than the second distance. The outer section member includes a cylindrical surface and is arranged concentrically around the inner section member, providing a gap therebetween. The inner section member and the outer section member can be embodied in a single backing piece, and the gap can be provided by one or more openings in the backing piece. The backing piece is capable of moving a small lateral distance from a central axis of the latch bracket. An inner sleeve includes an inner surface having an outwardly sloped portion at a proximal end adapted to fit against the outwardly sloped surface of the plunger. The first proximal o-ring provides a seal therebetween when the latch bracket is disconnected from the latch pin. The inner sleeve also includes an outer surface having an outwardly sloped portion near a distal end that includes an o-ring groove in which the outer proximal o-ring is positioned, and a cylindrical surface at a distal end that slidingly engages with the cylindrical surface of the inner section member. A inner middle o-ring provides a seal between the cylindrical surface of the inner section member and the cylindrical surface of the bracket inner sleeve. The bracket also includes a second sleeve, which has an inner surface having an outwardly sloped portion at a proximal end adapted to fit against the outwardly sloped surface of the outer surface of the inner sleeve. The outer proximal o-ring provides a seal therebetween when the latch bracket is disconnected from the latch pin. The second sleeve also has a cylindrical surface at a distal end that slidingly engages with the cylindrical surface of the inner section member. An outer middle o-ring is arranged to seal between the cylindrical surface of the outer section member and the cylindrical surface of the second sleeve. A bias member, such as a coil spring, is arranged to urge the second sleeve proximally against the inner sleeve and the inner sleeve against the plunger. With this arrangement, the inner channel is defined by the plunger, an inner surface of the inner section member and the inner surface of the inner sleeve. The outer channel is defined by an outer surface of the inner section member, the outer surface of the inner sleeve, the inner surface of the second sleeve, and an inner surface of the outer section member. 
     The latch bracket can further include a locking mechanism that inhibits the latch pin from retracting out from the latch bracket while fluid pressure is applied through the latch pin to the latch bracket. The locking mechanism can include a shuttle valve having first and second inlets coupled to the inner and outer channels, respectively, and an outlet. The locking mechanism also includes an outer sleeve arranged adjacent a middle section of the body, which is located between the end cap and the cylindrical bearing. The outer sleeve and the middle section define an annular chamber coupled therebetween. The outer sleeve has an inner cylindrical surface having a diameter approximately the diameter of the cylindrical bearing to receive a distal end of the latch pin. A fluid channel connects between the shuttle valve outlet and a distal end of the chamber. An annular shaped locking block located within the annular chamber is arranged to slide longitudinally therein to a proximal position when fluid pressure is applied to the chamber through the outlet. A plurality of locking members are arranged to extend radially inward from the inner cylindrical surface of the outer sleeve when the locking block moves to the proximal position. This engages the locking members in an annular groove formed on an outer surface of the latch pin. 
     The latch bracket can further include a fluid switch between the inner channel and the outer channel that is closed circuit when the latch pin is connected to the latch bracket to equalize pressures between the inner channel and the outer channel, and that is open circuit when the latch pin is connected to the latch bracket to allow for pressure differences between the inner channel and the outer channel. 
     In still another aspect, the invention provides a multi-line, rotatable fluid connector assembly, which includes a first part removably and rotatably connectable to a second part. Each of the first and second parts includes a plurality of fluid channels. Each of the plurality of fluid channels is adapted to connect to a corresponding fluid channel of the other of the first and second parts. Each of the plurality of fluid channels of each of the first and second parts includes an end seal arranged to inhibit fluid from spilling therefrom. The plurality of fluid channels of the first part, the second part, or both the first and second parts are arranged concentrically. 
     In another aspect, the invention provides a multi-line fluid connector, including first and second parts removably connectable with each other. The first and second parts each includes a plurality of fluid channels. 
     Each of the plurality of fluid channels is adapted to connect to a corresponding fluid channel of the other of the first and second parts when the first part is connected to the second part. Each fluid channel includes a respective end seal. The first part and the second part are cooperatively structured to provide a make-before-break connection between their respective corresponding fluid channels. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation view of a tool coupler according to the invention on the end of an arm positioned to engage a hydraulic grapple. 
     FIG. 2 is a side elevation view of the tool coupler of FIG. 1 attached to the hydraulic grapple. 
     FIG. 3 is a top plan view of the tool coupler of FIG. 1, shown detached from the arm and with its latch pin in a retracted position. A mating portion of the tool that receives the latch pin is partially shown in a broken away view. 
     FIG. 4 is a view similar to that of FIG. 3, illustrating the latch pin in the connected position. 
     FIG. 5 is a longitudinal section view along line  5 — 5  of FIG. 3, illustrating a multi-line hydraulic coupling according to the invention. A latch pin and a latch bracket are shown in an unlatched position. 
     FIG. 6 is an end view of the latch pin end cap viewed from line  6 — 6  of FIG.  5 . Internal features are shown in shadow. 
     FIG. 7 a side view of the latch pin plug. 
     FIG. 8 is an end view of the latch pin plug viewed along line  8 — 8  of FIG.  7 . 
     FIG. 9 is a longitudinal sectional view of the latch pin inner sleeve. 
     FIG. 10 is a longitudinal sectional view of the latch pin outer sleeve. 
     FIG. 11 is a distal end view of latch bracket end section. 
     FIG. 12 is a sectional view through line  12 — 12  of FIG. 5 showing the distal end section of the latch bracket in isolation. 
     FIG. 13 is a longitudinal sectional view of the latch bracket backing piece. 
     FIG. 14 is an end view of the backing piece along line  14 — 14  of FIG.  13 . 
     FIG. 15 is a distal end view of the latch bracket outer sleeve. 
     FIG. 16 is a section view through line  16 — 16  of FIG.  15 . 
     FIG. 17 is a longitudinal section view of the latch bracket middle sleeve. 
     FIG. 18 is a longitudinal section view of the latch bracket inner sleeve. 
     FIGS. 19-22 are sequential longitudinal section views illustrating the latch pin connecting with the latch bracket to form two fluid connections. FIG. 19 shows the latch pin initiating contact with the plunger of the latch bracket. FIG. 20 shows the first coaxial seal exchange. FIG. 21 shows the second coaxial seal exchange. FIG. 22 shows the completed connection. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a quick-connect tool coupler  10  is attached to a dipper stick  12  of a construction equipment, which can be a backhoe, an excavator and the like. Tool coupler  10  can be rotated about a dipper pivot  14  by actuating a bucket cylinder  16 , which is coupled by a linkage  18  to a link pivot  20  at a forward end of tool coupler  10 . A latch mechanism  21  (FIG. 3) in tool coupler  10  for connecting to a tool is structured substantially the same as the latch mechanisms of quick-disconnect tool couplers described in co-owned U.S. Pat. No. 5,727,342, the entire disclosure of which is included herein by reference. A detailed description of the latch mechanism in this type of tool coupler is provided in that patent, and therefore only a brief description will be provided here. 
     In FIG. 1, tool coupler  10  is positioned to engage a hydraulic grapple  22 . To engage tool coupler  10  with grapple  22 , an operator maneuvers a pair of crescent-shaped hooks  24  (only one shown) depending from tool coupler  10  to engage a cross bar  26  on the upper end of grapple  22 . The operator then extends bucket cylinder  16  to rotate tool coupler  10  counter-clockwise as shown in FIG.  2 . Referring now also to FIG. 3, this step aligns a latch pin  28  in tool coupler  10  with a latch bracket  30  on grapple  22 . Latch pin  28  is held in this retracted position by a latch cylinder  32 , which has its rod  34  extended against a latch pin bearing  36 . The operator then releases hydraulic pressure in latch cylinder  32 , which allows a coil spring  38  to slide latch pin  28  through latch pin bearing  36  and into engagement with latch bracket  30  as illustrated in FIG.  4 . These steps are carried out in reverse order to release grapple  22 . 
     Grapple  22  includes a pair of jaws  40 A,  40 B that are opened and closed by actuating a hydraulic grapple cylinder  42 . Latch pin  28  and latch bracket  30  form a two-part, nonspill, hydraulic fluid connector in a two-line fluid circuit bringing controlled hydraulic pressure to grapple cylinder  42 . A first pair of hydraulic fluid lines  44 A,  44 B connect between the hydraulic controls in the equipment and fittings inserted in ports of a latch pin head  46  on a proximal end of latch pin  28 . A second pair of hydraulic fluid lines  48 A,  48 B couple between latch bracket  30  and grapple cylinder  22 . The fluid connector includes two separate and substantially coaxial flow paths in each of latch pin  28  and latch bracket  30 . 
     The term “nonspill” as used herein refers to a sealing system wherein, for each flow path, a seal at the end of the flow path of one of the latch pin or latch bracket slides over to provide a seal with a portion of the other of the latch pin or latch bracket before the seal at the end of the corresponding flow path in the other of the latch pin or latch bracket opens to establish the fluid connection. In disconnecting the latch pin from the latch bracket, the seal at the end of the other of the latch pin or latch bracket flow path is reestablished before the sliding seal moves back. In this way, fluid is inhibited from leaking out of the system. This is also called a “make before break” type of connection. As will be described below with reference to the drawings, there is a dual seal within each fluid passageway. Each portion of the connector has seals that close fluid lines when the components are not connected and which resist spilling when making the connection. 
     The construction of the latch pin  28  will now be described with reference to FIG. 5, which will be followed by a description of the latch bracket  30 . Latch pin  28  includes an elongated, tubular latch pin body  50  that is connected, for example, by a continuous weld, at a proximal end to latch pin head  46 . The terms “proximal” and “distal” as used with reference to a described item will refer respectively to the right and the left sides of that item as viewed in FIG.  5 . Latch pin body  50  has a diameter of about 2.5 inches and a length of about 7.5 inches. Latch pin head  46  includes two boss ports  52 A,  52 B for coupling to respective hydraulic fluid lines  44 A,  44 B. Boss ports  52 A,  52 B are shown angularly displaced from their actual positions for clarity in FIG.  5 . Their relative positions are shown more accurately in FIG.  6 . Boss ports  52 A,  52 B receive fittings that connect to respective hydraulic lines  44 A,  44 B. Each of boss ports  52 A,  52 B communicates via a respective connecting channel  54 A,  54 B with a central opening  56  extending through latch pin body  50  and partially through latch pin head  46  from a distal end of latch pin  28 . A surface of central opening  56  includes a cylindrical proximal portion  58  within latch pin head  46  that has a smaller radius than a distal portion  60  that extends toward the distal end of central opening  56 . A tube  62  inserted into central opening  56  has an outer surface  63  at a proximal end that closely fits adjacent to cylindrical proximal portion  58 . An o-ring  64 , positioned in an o-ring groove  65  in tube outer surface  63 , provides a proximal seal between tube  62  and cylindrical proximal portion  58  of the surface of central opening  56 . The seal provided by o-ring  64  separates the interior of latch pin  28  into separate fluid channels  101 ,  102  as will be described in greater detail below. 
     Latch pin head  46  also includes a bore hole  66  threaded to receive latch pin cylinder  32 . A set screw (not shown) is threaded into a tapped side hole  68  to hold latch pin cylinder  32  in place. A recess  70  on the proximal side of latch pin head  46  receives and retains one end of coil spring  38  (See FIGS.  3  and  4 ). 
     Tube  62  extends about 80% of the length of latch pin body  50 . One side of a washer  72  rests against a distal facing shoulder  74  formed by an inner surface  75  of tube  62 . One end of an inner coil spring  76  presses against the other side of washer  72 . Referring now also to FIGS. 7-9, the distal end of coil spring  76  presses against a proximal end surface  77  of a plug  78 . Plug  78  has tapered sides  79  and is retained by a distal end of an inner sleeve  80 , which has an inwardly tapered portion  81  of an inner surface fitting against tapered sides  79  of plug  78 . The inner surface of inner sleeve  80  also has a cylindrical distal portion  82  that slides over a cylindrical distal surface  83  of plug  78 . An o-ring  84 , positioned in an o-ring groove  84 A in cylindrical distal portion  82  of the inner surface of inner sleeve  80 , provides a seal between plug  78  and inner sleeve  80  at surfaces  82 ,  83 . 
     Inner sleeve  80  further includes a cylindrical proximal inner surface  85  adapted to slide over a cylindrical distal outer surface  86  of tube  62 . Another o-ring  87  provides a seal between distal outer surface  86  of tube  62  and proximal inner surface  85  of inner sleeve  80 . o-ring  87  is positioned in an o-ring groove formed in distal outer surface  86  of tube  62 . In the described embodiment, a small aperture  87 A that extends radially through inner sleeve  80  is located a short distance from the distal end of tube  62 , just distally of o-ring  87 . 
     An outer coil spring  88  has a proximal end positioned against a distal facing shoulder  89  formed by an inner surface  89 A of latch pin body  50 . The distal end of coil spring  88  bears against a proximal facing shoulder  90  formed on an outer surface  90 A of inner sleeve  80 . The distal end of outer surface  90 A of inner sleeve  80  has an inwardly tapered portion  91 . Referring now also to FIG. 10, an outer sleeve  92  has an inner surface including a central tapered portion  93  that engages tapered portion  91  of the outer surface of inner sleeve  80 . Outer sleeve  92  is held in place by a snap ring  94  that fits in an annular groove formed in latch pin body  50 . One o-ring  95 , which sits in an o-ring groove  95 A, provides a seal between a cylindrical distal portion  96  of the inner surface of outer sleeve  92  and a cylindrical distal portion  97  of an outer surface of inner sleeve  80 . Another o-ring  98 , positioned in o-ring groove  98 A, provides a seal between an outer surface  99  of outer sleeve  92  and a cylindrical distal portion  100  of surface  89 A of latch pin body  50 . The distal surfaces of plug  78 , inner sleeve  80 , outer sleeve  92  and latch pin body  50  together provide a substantially flat end surface of latch pin  28  when latch pin  28  is in a retracted position within tool coupler  10 . By this arrangement, snap ring  94  retains outer sleeve  92 , which retains inner sleeve  80  against the spring force exerted against it by outer coil spring  88 . Inner sleeve  80  retains plug  78  against the spring force exerted against it by inner coil spring  76 . 
     This arrangement also provides two substantially concentric fluid channels within latch pin  28 . A central fluid channel  101  is coupled at a proximal end to boss port  52 A through connecting channel  54 A. Central channel  101  extends through the space inside tube  62 , and through the space inside inner sleeve  80  to plug  78 , where o-ring  84  provides an end seal. An outer fluid channel  102  couples to boss port  52 B through connecting channel  54 B. Outer channel  102  then extends distally through the annular space between outer surface  63  of tube  62  and inner surface  89 A of latch pin body  50 , and through the annular space between outer surface  90 A of inner sleeve  80  and inner surface  89 A of latch pin body  50  to outer sleeve  92 , where o-rings  95  and  98  provide end seals. O-rings  64  and  87  provide seals between central channel  101  and outer channel  102 . Central and outer channels  101 ,  102  are weakly connected through aperture  87 A in inner sleeve  80 , which ensures that the pressures will be equalized between inner and outer channels  101 ,  102  when tool coupler  10  is not connected to a tool. 
     As described above, latch pin  28  is extended distally by coil spring  38  (FIG. 3) and retracted proximally by extending rod  34  of latch pin cylinder  32 . Latch pin bearing  36  restricts latch pin  28  to longitudinal motion. Latch pin bearing  36  includes a latch pin bearing sleeve  104  suitable for use as a slide bearing. Latch pin bearing  36  also includes an arcuate collar  106  on a distal end. Collar  106  is shaped to stop against an upper surface of latch bracket  30  so as to hold tool coupler  10  in a proper lateral position for inserting latch pin  28  into latch bracket  30 . 
     Latch bracket  30  includes three sections that are bolted together: a proximal end section  108  closest to the distal face of latch pin  28 ; a middle section  110 ; and a distal end section  112 . Latch bracket has an assembled length of about 6.6 inches and a diameter of about 4.5 inches. Proximal end section  108  has a body  114  extending through an aperture in a support plate  116  on grapple  22 , and is welded or otherwise secured thereto. A cylindrical latch bracket bearing sleeve  118  positioned within a central bore of body  114  aligns with latch pin bearing sleeve  104  when collar  106  is positioned against body  114  so as to receive latch pin  28  in the extended and locked position. 
     Referring now also to FIGS. 11 and 12, distal end section  112  includes a body, or end cap  119 , having an outer bore  120 . Outer bore  120  has a diameter of about 2.72 inches and extends to a depth of about 0.314 inch from a proximal end face  121  of end cap  119 . An annular groove  122  is formed concentrically within outer bore  120 . Annular groove  122  has an inner diameter of about 1.409 inches, a width of about 0.188 inch, and a depth of about 0.188 inch from a bottom surface  123  of outer bore  120 . A deeper segment  124  of annular groove  122  is formed to an additional depth of about 0.745 inch. A central inner bore  126  has a diameter of about 0.688 inch and extends to a depth of about 0.927 inch from bottom surface  123  of outer bore  120 . The center of inner bore  126  includes a tapped bore  128  that is tapped with a {fraction (5/16)}-18 thread about 0.62 inch deep. An elongated plunger  129 , screwed into tapped bore  128  or otherwise secured at the bottom of inner bore  126 , extends through inner bore  126  and out past middle section  110  of latch bracket  30 . 
     Four bolt holes  130  are provided for assembling distal end section  112  with the other two sections of latch bracket  30 . Similarly arranged bolt holes (not shown) are provided in a middle section body  131  and proximal end section body  114 . The bolt holes in proximal end section body  114  may be threaded or may be clear holes with recessed areas on a proximal side to receive nuts. 
     Two boss ports  132 A,  132 B extend diametrically into end cap  119 . Boss ports  132 A,  132 B receive fittings that connect to respective hydraulic lines  48 A,  48 B. Boss port  132 A is in fluid communication with inner bore  126  via one connecting channel  134 A, and boss port  132   b  is in fluid communication with deeper segment  124  of annular groove  122  via another connecting channel  134 B. Secondary connecting channels  136 A,  136 B connect between respective boss ports  132 A,  132 B and end ports of a shuttle valve  139  (see FIG.  5 ), positioned within a side chamber  138 . Shuttle valve  139  allows fluid flow from the higher pressure of its end ports to a middle port. In the described embodiment, shuttle valve  139  is a model LS04-B30 ball-type, screw-in shuttle valve, available from Hydra Force, Inc. of Lincolnshire, Ill. A third channel  140  extends longitudinally from the middle port of shuttle valve  139  to proximal end face  121  to connect with another longitudinal channel  164  in middle section body  131  as will be described below. 
     Referring now also to FIGS. 13 and 14, a backing piece  142  is located with its distal end face  144  adjacent bottom surface  123  of outer bore  120  of end cap  119 . Backing piece  142  includes a central opening  146 , a substantially annular shaped inner section  148  centered on central opening  146 , and a substantially annular shaped outer section  150  coaxial with inner section  148 . Inner and outer sections  148 ,  150  are connected by supporting members  152  defining a ring of circular apertures  154  located between inner and outer sections  148 ,  150 . Backing piece  142  is held against end cap  119  by a coil spring  193 , which presses against a proximal facing surface  155  of outer section  150 . As can be seen in FIG. 5, there is a small radial gap  153 , e.g. about {fraction (1/32)} inch, between outer section  150  of backing piece  142  and a cylindrical surface of end cap  119 . This permits backing piece  142  to move a small lateral distance within end cap  119 . 
     Central opening  146  communicates with central bore  126  of distal end section  112 , while apertures  154  communicate with annular groove  122  and deeper section  124  of distal end section  112 . An outer o-ring  156 , which is positioned in an outer o-ring groove  157 , provides a seal between end cap  119  and backing piece  142  outside the diameters of outer opening  154  and annular groove  122 . An inner o-ring  158 , positioned in an inner o-ring groove  159 , provides a seal between end cap  119  and backing piece  142  inside the ring of apertures  154  and the diameter of annular groove  122  and outside the diameters of central bore  126  and central opening  146 . 
     Middle section body  131  has a central opening defined by a stepped inner surface  133 . A substantially annular-shaped locking ring  160  is positioned in an outer step  162 . Longitudinal channel  164  extends from outer step  162  through to a distal end of middle section  110 , and is aligned with channel  140  in distal end section  112 . An o-ring  165  between middle section body  131  and end cap  119  provides a seal around the connection between channels  140 ,  164 . O-ring  166  provides a seal between locking ring  160  and surface  133 . 
     Referring now also to FIGS. 15 and 16, an outer sleeve  168  is positioned in an inner step of surface  133  adjacent to locking ring  160 . Outer sleeve  168  includes a cylindrical inner surface  170  providing a central opening  172 . An outer surface includes a cylindrical distal portion  174 , a central outwardly sloped portion  176 , and a proximal cylindrical portion  178 . The outer surface of outer sleeve  168  and stepped surface  133  of middle section body  131  define an annular shaped chamber  256  connected at a distal end to longitudinal channel  164 . Locking ring  160  slides laterally when fluid pressure is applied to chamber  256  through longitudinal channel  164 . O-ring  177  provides a seal between distal cylindrical surface  174  and surface  133  of middle section body  131 . Another o-ring  179  provides a seal between distal cylindrical surface  174  and an inner cylindrical surface of locking ring  160 . O-rings  166 ,  177 ,  179  seal chamber  256 . 
     Spaced evenly around outer sleeve  168  at a juncture between cylindrical distal surface  174  and outwardly sloped surface  176  are sixteen radially extending, tapered apertures  180 , which are larger on an outer surface than on inner surface  172 . Inside each aperture  180  is a ball bearing  182 . Locking ring  160  responds to fluid pressure in channel  164  by sliding in a proximal direction between step surface  162  and outer sleeve  168 . This causes an outwardly sloped proximal surface  183  of locking ring  160  to push ball bearings  182  radially inward. 
     In the unlatched position shown in FIG. 5, ball bearings  182  contact an inwardly tapered outer rim  184  of a flange  185  on a middle sleeve  186 . Referring now also to FIG. 17, which shows middle sleeve  186  in isolation, an outer surface of middle sleeve  186  includes a cylindrical distal portion  188  in sliding contact with a cylindrical inner surface  190  of a proximal end of outer section  150  of backing piece  142 . An o-ring  192  positioned in an o-ring groove  192 A provides a seal between surfaces,  188  and  190 , of middle sleeve  186  and backing piece  142 , respectively. Middle sleeve  186  is urged in a proximal direction by coil spring  193 , positioned between proximal facing surface  155  of backing piece  142  and a distally facing surface  191  (FIG. 12) of flange  185  of middle sleeve is  186 . 
     Middle sleeve  186  in turn, is retained in position by an inner sleeve  194 , which is, in turn, held in position by plunger  129 . Referring now also to FIG. 18, which shows inner sleeve  194  in isolation, an outer surface  195  of inner sleeve  194  includes an cylindrical distal portion  196  in sliding contact with a cylindrical inner surface  198  of inner section  148  of backing piece  142 . An o-ring  200  that sits in an o-ring groove  197  in inner section  148  provides a seal between cylindrical surface portions  198  and  196 . In the described embodiment, a small aperture  199  that extends radially through inner sleeve  194  is located just proximally of inner section  148  of backing piece  142 . An inner surface  201  of middle sleeve  186  has an outwardly sloped proximal portion  202  urged by spring  193  into contact with a similarly sloped proximal portion  204  of an outer surface  195  of inner sleeve  194  when latch bracket  30  is in the unlatched position shown in FIG.  5 . This also urges an outwardly sloped portion  206  at the proximal end of an inner surface  207  of inner sleeve  194  into contact with plunger  129  at a similarly sloped portion  208  of an enlarged proximal end of a surface  209  thereof. Sloped portion  208  of plunger surface  209  thus retains inner sleeve  194  and middle sleeve  186  in place against the bias force of spring  193 , which urges these pieces proximally out of latch bracket  30 . One o-ring  210  that sits in an o-ring groove  211  in inner sleeve  194  provides a seal between sloped surface portions  202 ,  204  of middle and inner sleeves  186 ,  194 , respectively. Another o-ring  212  provides a seal between surfaces  206 ,  208  of inner sleeve  194  and plunger, respectively, and is located in an o-ring groove  213 . 
     As is now apparent from the above description, latch bracket  30 , like latch pin  28 , includes two substantially concentric fluid channels. An annular inner fluid channel  214  is substantially defined by longitudinal surface  209  of plunger  129 , o-ring  212 , inner surface  207  of inner sleeve  194 , o-ring  200 , inner surface  198  of inner section  148  of backing piece  142 , o-ring  158 , and central bore  126  of distal end section  112 . Inner fluid channel  214  connects to hydraulic fluid line  48 A, as described above, through connecting channel  134 A and boss port  132 A. A substantially annular outer fluid channel  216  is substantially defined by o-rings  156 ,  158 , an outer surface  218  of inner section  148  of backing piece  142 , outer surface  195  of inner sleeve  194 , o-ring  210 , inner surface  201  of middle sleeve  186 , o-ring  190 , an inner surface  220  of outer section  150  of backing piece  142 , and annular groove  122  of distal end section  112 . Outer channel  216  connects to hydraulic fluid line  48 B  30  through connecting channel  134 B and boss port  132 B. In the unlatched configuration illustrated in FIG. 5, inner and outer channels  214 ,  216  of latch bracket  30  are weakly connected through aperture  199  in latch bracket inner sleeve  194 . This feature equalizes the pressure between inner and outer channels  214 ,  216  when latch bracket  30  is unconnected from latch pin  28 . 
     To assemble latch pin  28 , latch pin body  50  is first fastened to latch pin head  46 . Tube  62 , with o-rings  64 ,  87  each positioned in respective o-ring grooves  65 ,  87 A, is fully inserted within pin body  50  so that it abuts the proximal end of central opening  56 . With latch pin head  46  resting on its proximal end, washer  72  is dropped into tube  62  so that washer  72  rests upon shoulder  74 . Inner coil spring  75  is dropped into tube  62 , such that it is supported by washer  72 . Outer coil spring  88  is then dropped into latch pin body  50  central opening  56  over tube  62  so that outer coil spring  88  rests on shoulder  89  of inner surface  89 A of latch pin body  46 . Plug  78 , inner sleeve  80  and outer sleeve  92  are assembled separately, with o-rings  84 ,  95 ,  98  positioned in respective o-ring grooves  84 A,  95 A,  98 A. The sub-assembly of plug  78 , inner sleeve  80  and outer sleeve  92  is then positioned within central opening  56  of latch pin body  50 . In this manner, proximal end surface  77  of plug  78  contacts inner coil spring  76 , inner surface  85  of inner sleeve  80  is positioned to slide over cylindrical distal outer surface  86  of tube  62 , shoulder  90  of inner sleeve contacts outer coil spring  88 , and outer sleeve  92  is positioned concentric to inner sleeve  80 . After pushing the sub-assembly of plug  78 , inner sleeve  80 , and outer sleeve  92  into position, snap ring  94  is inserted to retain the sub-assembly in place against the forces exerted by springs  76 ,  88 . 
     Latch bracket  30  is assembled in the following manner. Distal end cap  112  is turned so that center bore  126  is exposed. O-rings  156 ,  158 ,  192 , and  200  are positioned within respective o-ring grooves  157 ,  159 ,  192 A,  197  of backing piece  142 , which is then positioned within the opening of end cap  112 . Coil spring  193  is then positioned on surface  155  of backing piece  142  and middle sleeve  186  is positioned on spring  193  and inside outer section  150  of backing piece  142 . Inner sleeve  194  is then placed inside middle sleeve  186  and inner section  148  of backing piece  142 . Plunger  129  is then inserted inside inner sleeve  194 . Spring  193  is compressed by screwing the distal end of plunger  129  into threaded bore  128  of end cap  112 . Sloped portion  208  of plunger surface  209  contacts sloped portion  206  of inner surface  207  of inner sleeve  194  when plunger  129  is positioned properly. 
     Latch bracket middle section  110  is assembled by the following steps. First, o-ring  177  is positioned in the appropriate o-ring groove of middle section body  131  and o-rings  166 ,  179  are positioned in their respective o-ring grooves of locking ring  160 . Locking ring  160  is then slipped over outer sleeve  168 , leaving a gap between surface  183  of locking ring  160  and surface  176  of outer sleeve  168 . With outer sleeve  168  standing on its distal end, ball bearings  182  are then dropped into the gap until each is positioned in one of tapered apertures  180 . Locking ring  160  is next moved up proximally against ball bearings  180  to hold them in place. The assembly consisting of locking ring  160 , outer sleeve  168  and ball bearings  180  is then inserted into middle section body  131  until the distal end of outer sleeve  168  butts up against a step formed in inner surface  133  of middle section body  131 . 
     To complete assembly of latch bracket  30 , bolts (not shown) are inserted through bolt holes  130  in end cap  119  and distal end section  112  is positioned upright on its distal end. Middle section body  131  is placed on end cap  119  with channels  140 ,  164  aligned, such that the bolts extend through appropriately placed bolt holes (not shown) in middle section body  114 . Proximal end section  108  is then placed on top of middle section  110  such that the bolts fit into respective bolt holes (not shown) in proximal end section  108 , and the assembly is secured by tightening the bolts. 
     In the unlatched position shown in FIG. 5 each of central and outer fluid channels  101 ,  102  of latch pin  28  are sealed at a distal end of latch pin  28 , even when positive fluid pressure is applied in these channels  101 ,  102 . Also, each of inner and outer fluid channels  214 ,  216  of latch bracket  30  are sealed at a proximal end, and remain closed even when some residual fluid pressure remains in latch bracket  30 . As will be described below, when latch pin  28  and latch bracket  30  are fully connected together, central fluid channel  101  of latch pin  28  and inner fluid channel  214  of latch bracket  30  are coupled together in fluid communication, and outer fluid channel  102  of latch pin and outer fluid channel  216  of latch bracket  30  are coupled in fluid communication with each other. The connection is made in a non-spill manner, such that hydraulic fluid does not leak from either latch pin  28  or latch bracket  30  at any time during the connection process. Seals are maintained to inhibit fluid leaking out from any of the channels or from cross-leaking between channels when latch pin  28  and latch bracket  30  are in a coupled position. 
     The operation of the latching mechanism will now be described with reference to FIGS.  5  and  19 - 22 . Normally, hydraulic pressure will be released from fluid channels  101 ,  102  prior to coupling. Some residual fluid and pressure may remain in either or both fluid channels  101 ,  102 . This pressure would be equalized by a small flow through aperture  87 A in the described embodiment. Similarly, any residual pressure that may be left in channels  214 ,  216  in latch bracket  30  would be equalized by flow through aperture  199 . 
     When hydraulic pressure in latch pin cylinder  32  is released, spring  38  moves latch pin  28  very quickly through bearing sleeves  104 ,  118 , from an unconnected position shown in FIG. 5 to a locked position shown in FIG.  22 . Referring first to FIG.  19  and also referring again to FIG. 5, after latch pin  28  has traveled through most of proximal end section  108  of latch bracket  30 , a distal end face  222  of plug  78  makes first contact with a proximal end face  224  of plunger  129 . As latch pin  28  continues to move distally into latch bracket  30 , plug  78  is stopped from further movement by plunger  129 , which is rigidly attached to end cap  119 . However, the remainder of latch pin  28  continues to move distally into middle section  110 . 
     As seen best in FIG. 20, cylindrical distal portion  82  of the inner surface of inner sleeve  80  of latch pin  28  has a diameter just large enough to slide over a cylindrical outer surface  226  of a proximal end of inner sleeve  194  of latch bracket  30 . As inner sleeve  80  of latch in  28  slips over inner sleeve  194  of latch bracket  30 , plug  78  is pushed proximally deeper into latch pin  28  by plunger  129  working against the bias force of inner coil spring  76 . This also causes o-ring  84  to slide off cylindrical distal outer surface  83  of plug  78  and onto cylindrical outer surface  226  of inner sleeve  194  in a continuous manner such that the seal at the end of central channel  101  does not leak. 
     When a distal end face  228  of latch pin inner sleeve  80  reaches a proximal facing surface  230  of latch bracket inner sleeve  194 , inner sleeve  80  is stopped from further movement. Referring now also to FIG. 21, latch pin  28  has moved beyond inner section  108  of latch bracket  30  and into middle section  110 . Cylindrical distal portion  96  of the inner surface of latch pin outer sleeve  92  has a diameter slightly larger than a cylindrical proximal outer surface  232  of latch bracket middle sleeve  186 . This allows latch pin outer sleeve  90  to slide over middle sleeve  186  while o-ring  95  continuously maintains a seal at the end of outer channel  102 . Meanwhile, tube  62  slides inside latch pin inner sleeve  80 , as o-ring  87  maintains the seal between their respective outer and inner surfaces  86 ,  85 . Note that aperture  87 A is now located proximally of o-ring  87 , so that central channel  101  is sealed off from outer channel  102 . 
     As latch pin  28  continues to move distally into latch bracket  30 , a distal end face  234  of latch pin body  50  and a distal end face  236  of outer sleeve  92  both make contact with a proximal facing surface  238  of middle sleeve  186  of latch bracket  16 . A beveled distal corner  240  of latch pin body  50  also makes contact with balls  182 . Central and outer channels  101 ,  102  in latch pin  28  remain closed through this point, as do inner and outer channels  214 ,  216  in latch bracket  30 . Coil springs  76 ,  88  in latch pin  28  have both been compressed, but coil spring  193 , which is a much heavier spring than coil springs  76 ,  88 , has not been compressed to any significant degree. 
     Latch pin  28  continues to slide distally into latch bracket  30  under the force of coil spring  38 , moving between the position shown in FIG.  21  and the position shown in FIG. 22, which is a terminal position. Latch pin body  50  and latch pin outer sleeve  92  push latch bracket middle sleeve  186  distally against the countering bias force of spring  193 . As middle sleeve  186  is pushed back, outer spring  88  in latch pin  28  forces latch pin inner sleeve  80  to push latch bracket inner sleeve  194  back along with middle sleeve  186 . This moves latch bracket inner sleeve  194  back and away from plunger  129 , closing the fluid circuit between central channel  101  in latch pin  28  and inner channel  214  in latch bracket  30 . Plug  78  includes flutes  242  cut into a proximal end to better enable fluid flow around plug  78  from central channel  101  to inner channel  214  (see, also, FIGS.  7  and  8 ). In addition, plug  78  includes a circular ridge  243  on a proximal side that helps to keep inner coil spring  76  centered on plug  78  and plug  78  centered on plunger  129 . At this point, outer fluid channel  102  in latch pin  28  is still sealed, as is outer fluid channel  216  in latch bracket  30 . 
     Latch bracket inner sleeve  194  slides distally within inner section  148  of backing piece  142  until a distal end  244  of inner sleeve  194  reaches bottom surface  133  of outer bore  120  of end cap  119 . At some time in this travel, aperture  199  moves to the distal side of o-ring  200 , which closes off the small passageway provided by aperture  199  between inner and outer channels  214 ,  216  in latch bracket  30 . 
     This also prevents further movement of latch pin inner sleeve  80 , but tube  62  continues to slide distally within inner sleeve  80  as latch pin  28  continues moving. Latch pin  28  also continues to push middle sleeve  186  distally until distally facing surface  191  of flange  185  moves close to a proximal end  246  of backing piece  142 . At this point, as shown in FIG. 22, a proximal end  248  of latch pin inner sleeve  80  is close to a shoulder  250  formed on an outer surface  252  of tube  62 . In addition, latch pin body  50  has slid deep enough into latch pin bracket  30  such that balls  182  can move into an annular groove  254  formed on an outer surface of latch pin body  50 . 
     The continued movement of middle sleeve  186 , while at the same time inner sleeve  194  is stopped, opens the seal provided by o-ring  210  between inner sleeve  194  and middle sleeve  186 . This closes the fluid circuit between outer fluid channel  102  in latch pin  28  and outer fluid channel  216  in latch bracket  30 . Now both fluid circuits are connected, with central channel  101  in fluid communication with inner channel  214  and outer channel in fluid communication with outer channel  216 , and grapple  22  is secured to tool coupler  10 . 
     Latch mechanism  21  includes a hydraulic locking mechanism that inhibits release of latch pin  28  when fluid pressure is applied to the attached tool through the fluid connector. Locking ring  160  is free to slide longitudinally in annular chamber  256  provided between latch bracket outer sleeve  168  and middle section body  131 . Shuttle valve  139  reacts to fluid pressure in either of channels  214 ,  216  by permitting fluid from the higher pressure side to flow into channel  140 . Channel  140  is in fluid communication with longitudinal channel  164 , which is in fluid communication with annular chamber  256 . O-rings  166 ,  177 ,  179  provide seals inhibiting the fluid from leaking out of annular chamber  256 . Fluid pressure in annular chamber  256  causes locking ring  160  to slide proximally to the end of annular chamber  256 . This causes a sloped proximal surface  258  of locking ring  160  to push balls  182  radially inward into annular groove  254  of latch pin body  50  and holds them there under the applied hydraulic pressure. Thus, so long as hydraulic pressure is applied through at least one of the fluid channels in the connector, latch pin  28  is inhibited from being accidentally disconnected from latch bracket  28 , which could release grapple  22  or other tool from tool coupler  10 . Moreover, fluid pressure is maintained in grapple  22 , preventing accidental release of material being held by grapple  22 . For both these reasons, the locking feature provides an added measure of safety for ground personnel working near the equipment to which the tool is attached. 
     The described connector is designed so that it does not require perfect alignment between latch pin  28  and latch bracket  30 . Latch pin  28  is substantially well aligned with latch bracket  30  before their internal parts begin to couple because of the close fit between latch pin body  50  and latch bracket bearing sleeve  118 . Most lateral movement of latch pin  28  is inhibited because of this fit. In addition, backing piece  142  has some room to move laterally within gap  153 . This permits the sliding parts, such as sleeves  80 ,  186 , and  194 , to align properly during the connecting process. When a tool, such as grapple  22 , is in use, there will be some small lateral jostling of latch pin  28  within latch bracket  30 . Gap  153  provides some room for back piece  142  to also move, which helps maintain integrity of the seals within the connector. 
     To disconnect a tool, such as grapple  22 , from tool coupler  10 , the operator first reduces hydraulic pressure in lines  44 A,  44 B, which reduces hydraulic pressure in the attached tool. This also releases pressure in the hydraulic locking mechanism described above, permitting latch pin  28  to be retracted from latch bracket  30 . With the tool resting on the ground and bucket cylinder extended  16 , the operator applies hydraulic pressure to latch cylinder  32 . This extends rod  34  against latch pin bearing  36 , which is fixed to the frame of tool coupler  10 . Extending rod  34  moves latch pin head  46  (and the rest of latch pin  28 ) proximally and counter to the bias force exerted by coil spring  38 . As latch pin  28  is pulled back, spring  88  keeps latch bracket inner sleeve  194  in place against end cap  119 , while latch bracket middle sleeve  186  follows latch pin  28  under the force exerted by coil spring  193 . Sloped proximal portion  202  of inner surface  201  of middle sleeve  186  contacts sloped proximal portion  204  of outer surface  195  of inner sleeve  194 , and starts to push inner sleeve with middle sleeve  186 . O-ring  210  reseals outer channel  216  with contact between middle sleeve  186  and inner sleeve  194 . Eventually, inner sleeve  194  is carried proximally to make contact with plunger  129  again, and o-ring  212  reseals inner channel  214 . With latch pin  28  retracting further, latch pin outer sleeve  92  slides back over latch pin inner sleeve  80 , reestablishing an end seal for outer fluid channel  102  with o-ring  95 . Next, tapered portion  93  of the inner surface of outer sleeve  92  contacts tapered portion  91  of the outer surface of inner sleeve  80 , and outer sleeve  92  starts pulling inner sleeve  80  proximally with latch pin body  50 . Inner sleeve  80  slides back over plug  78 , and o-ring  84  reseals the distal end of central fluid channel  101 . 
     With latch pin in the position shown in FIG. 19, latch bracket inner sleeve  194  has slid proximally to a point where aperture  199  again provides a connection between inner and outer fluid channels  214 ,  216  in latch bracket. Similarly, latch pin inner sleeve  80  has moved to a position where aperture  87 A communicates between central and outer fluid channels  101 ,  102  in latch pin  28 . All fluid channels are sealed in both latch bracket  30  and latch pin  28  such that fluid cannot leak out. 
     At this point, latch pin  28  is still within latch bracket  30 , and so the tool is still securely attached to tool coupler  10 . When latch pin  28  is fully withdrawn from latch bracket  30 , the operator can rotate tool coupler  10  away from the tool and disengage hooks  24 , as described in U.S. Pat. No. 5,727,342. 
     It is apparent from the above description that latch pin  28  and latch bracket  30  would be capable of rotating relative to each other about their common longitudinal axis were they not attached to tool coupler  10  or grapple  22 , respectively. Both latch pin  28  and latch bracket  30  have a high degree of rotational symmetry about their common central axis. Central and outer channels  101 ,  102  in latch pin body  50  are substantially concentric throughout their lengths. Similarly, inner and outer channels  214 ,  216  in latch bracket  30  are also substantially concentric. O-rings  64 ,  84 ,  87 ,  95 ,  190  and  200  are all concentric with the central axis, and permit relative rotation of the parts that they respectively seal. Ball bearings  182  enable latch pin body  50  to rotate relative to latch bracket  30 . Moreover, most internal surfaces are bathed in hydraulic oil, which lubricates moving parts. 
     This rotational capability allows, the invention to provide a rotatable, multi-line fluid connector. The described connector can be employed in a coupling mechanism to a rotatable tool, such as a rotatable hanging grapple. The rotation feature can be enhanced by inserting bearing rings in strategic locations, such as between washer  47  and shoulder  72 , between coil spring  193  and flange distal facing surface  191  of latch bracket middle sleeve  186 , and between coil spring  88  and shoulder  248  of latch pin body  50 . 
     While in the above described embodiment the hydraulic grapple includes a double action hydraulic cylinder  42 , the described tool coupler  10  can also be employed to engage tools having one or more single action hydraulic cylinders or tools having no hydraulic cylinders. When employing a tool with one single action cylinder, a plug would be inserted in one of ports  52 A,  52 B, and the other of ports  52 A,  52 B on latch bracket  30  would be connected to the hydraulic cylinder. Tools not having any hydraulics could include a latch bracket without hydraulic connector parts, as described in U.S. Pat. No. 5,727,342, instead of latch bracket  30 . 
     It should also be understood that the fluid connecting parts in latch pin  28  can be incorporated into latch bracket  30 , and the fluid connecting parts in latch bracket can be incorporated into latch pin  28 . For example plunger  129 , latch bracket inner sleeve  194 , latch bracket middle sleeve  186  and backing piece  142  could be located in a latch pin, while plug  78 , tube  62 , pin inner sleeve  80  and pin outer sleeve  92  could be incorporated into a latch bracket. 
     It will be apparent to those of skill in the art that the above described embodiment of a multi-line fluid connector, which includes two fluid lines, is constructed with features that are applicable to the design and construction of fluid connectors with more than two fluid lines according to the invention. Among these features are concentric fluid lines, make-before-break seals, and spring assisted closures. 
     The multi-line fluid connector of the invention can be used in couplers having a latching member that is different from a cylindrical latch pin. The multi-line fluid connector can be employed in fields outside of the construction equipment industry, and with fluids other than hydraulic fluids. 
     Other embodiments are within the scope of the following claims.