Abstract:
A fluid coupling including coded and non-coded embodiments and a method for their use. The coded embodiment allows connection of such lines while preventing the inadvertent connection of mismatched lines in a system where there are matched and mismatched delivery and supply lines. Both embodiments of the coupling include axially movable first and second coupling members and a radially operating latch. The coupling members are releasably slideably, axially interfitted with their fluid passageways in communication, and the latch moves radially of the passageways to secure the couplings when they are interfitted. In the coded embodiment, key coding elements on the coded coupling members are movable into matched interengagement when the supply and delivery lines are matched but are precluded from moving into matched interengagement when the lines are mismatched. If a match exists, the coding elements interfit by limited rotation of one of the key coding elements but without rotation of the coupling members and without any threading action of the parts. A mechanism latches the couplings together when the key coding elements match and allow the coupling members to interfit but does not latch when the key coding elements do not match and thus do not allow an interfit. In both embodiments, the coupling members are uncoupled solely by axial separation of the parts, again with out threading, and in the case of the first embodiment, without even any rotation of the parts. In both cases, therefore, neither the coupling members, the coding elements, nor the latch involves threaded connections, whether for connection or disconnection or for latching or unlatching.

Description:
RELATED APPLICATION 
     This application is a continuation of our prior application Ser. No. 09/085,382, filed May 26, 1998 now abandoned, originally entitled Quick-Connect Coupling and amended to be entitled Coupling. 
    
    
     FIELD OF THE INVENTION 
     The present invention pertains to a fluid coupling and more particularly to a fluid coupling having coupling members that are quickly connectable and disconnectable and also to a coded fluid coupling that is quickly connectable and latchable but only if the coupling members match and to a method for their use. 
     BACKGROUND 
     In various industries, it is necessary to use many chemicals in the manufacturing process. In the semiconductor industry, for example, some fifteen to twenty liquid chemicals are typically stored in adjacent fifty-gallon supply drums from which they are dispensed during the manufacture of the semiconductors. In the usual installation, sets of separate umbilical delivery lines for various chemicals are suspended above the drums with a particular set dedicated to a particular chemical. Each set of delivery lines is connected to its associated supply drum by a coupling that has one coupling member on the delivery lines and a second coupling member on the drum. 
     As each supply drum is emptied during the manufacturing process, a full drum is brought in to replace the empty one. Accordingly, the coupling members must be repeatedly connected and disconnected. Because of the incompatibility of the chemicals, it is critical that each set of delivery lines be connected only to its intended drum to avoid unsafe mixing and undesired contamination. Moreover, to maintain productivity, such connections and disconnections must be made quickly and routinely by production personnel. 
     To insure correct connection of delivery lines to their intended supply drums, the known chemical extraction apparatus uses fluid couplings that incorporate matching coding elements on the coupling members. Examples of such fluid couplings and their coding devices are shown and described in the U.S. Pat. No. 4,699,298 to Grant et al. and U.S. Pat. No. 5,108,015 to Rauworth et al. A significant disadvantage of these known couplings, however, is that they cannot be as quickly connected and disconnected as is desired. Although referred to as quick-connect couplings, they use threaded parts to secure the connection. Repeated threading and unthreading of couplings over a production run consumes a significant amount of valuable time and also can produce additional delays if the threads become fouled and otherwise fail to mesh properly. 
     Fluid couplings that can be connected and disconnected without threading are of course available and are truly quick-connect and -disconnect couplings. Examples of known quick-connect couplings are disclosed in U.S. Pat. No. 4,436,125 to Blenkush and U.S. Pat. No. 5,052,725 to Meyer et al. Such known couplings of this type, however, are not suitable for the chemical extraction industry or other industries where matched connections are mandatory since they make no provision for coding, that is, insurance against making mismatches. Moreover, the latching mechanisms used in such known quick-connect couplings do not lend themselves to balanced and dependable two-handed operation by personnel in production processes such as described above. 
     The copending reissue application of Kazarian, Application Ser. No. 091693,627, filed Oct. 20, 2000 which is a reissue of U.S. Pat. No. 6,007,107 granted Dec. 28, 1999 which is based on Kazarian Application Ser. No. 08/683,516, filed Jul. 12, 1996, entitled Fluid Coupling For Matching Delivery and Supply Lines Irrespective Of The Relative Rotational Positions Of The Coupling Members, and having a common assignee with the present application, is one solution to the problems set forth above. The invention of the present application provides an alternative solution. 
     SUMMARY 
     A fluid coupling including coded and non-coded embodiments and a method for their use are provided. The coded embodiment allows interconnection of only matching fluent material delivery and supply lines while preventing the inadvertent connection of mismatched lines in a system where there are matched and mismatched delivery and supply lines. Both embodiments of the coupling include axially movable first and second coupling members and a radially operating latch. The coupling members are releasably slideably, axially interfitted with their fluid passageways in communication, and the latch moves radially of the passageways to secure the couplings when they are intermitted. In the coded embodiment, key coding elements on the coded coupling members are movable into matched interengagement when the supply and delivery lines are matched but are precluded from moving into matched interengagement when the lines are mismatched. If a match exists, the coding elements interfit by limited rotation of one of the key coding elements but without rotation of the coupling members and without any threading action of the parts. A mechanism latches the couplings together when the key coding elements match and allows the coupling members to interfit but does not latch when the key coding elements do not match and thus do not allow an interfit. In both embodiments, the coupling members are uncoupled solely by axial separation of the parts, again with out threading, and in the case of the first embodiment, without even any rotation of the parts. In both cases, therefore, neither the coupling members, the coding elements, nor the latch involves threaded connections, whether for connection or disconnection or for latching or unlatching. 
     An object of this invention is to provide an improved fluid coupling. 
     Another object is to provide a coded quick-connect and disconnect coupling for use in a chemical extraction system involving supply drums of chemicals and separate delivery lines suspended above the drums. 
     A further object is to improve the productivity and safety of dispensing a plurality of incompatible chemicals through different delivery lines from different supply drums in a manufacturing process. 
     A still further object is to provide a simplified coupling that enables dependable quick connection and quick disconnection of the coupling members. 
     Additionally, an object is to reduce the manufacturing costs of a quick-connect coupling. 
     Another object is to provide an interactive key coding system and latching mechanism in a quick-connect coupling wherein the coupling members cannot be coupled and latched unless they match. 
     Yet another object is to provide a simplified quick-connect coupling that does not involve threading or unthreading of the parts. 
     An additional object is to provide a coupling for supply and delivery lines that allows establishing a coupling without twisting of the lines or relative rotation of the coupling members or threading of the parts and without regard to the relative rotational positions of the coupling members prior to or during interfitting thereof. 
     A still further object is to provide a key-coded, quick-connect coupling that does not require swiveling of its coupling members for connection but permits the parts being coupled to swivel relative to each other without affecting the rapidity of interconnecting matched coupling members and without affecting the operation of coupling. 
     Another object is to minimize the time required dependably to connect and disconnect matched coupling members of a coded coupling or to determine that the coupling members are mismatched and will not couple. 
     An additional object is to provide a key coding system for a coupling that can handle many different combinations of matches and mismatches. 
     Yet another object is to provide a balanced coding system for a coded quick-connect coupling that lends itself to two-handed operation by a user. 
     A still further object is to provide an indicator that allows an operator to confirm whether the coupling members are matched and interfitted or whether they are mismatched and not interfitted. 
     Another object is to isolate the coding and latching elements of a quick-connect coupling from the fluids carried by the coupling and to provide such elements with protection from the fluids. 
     An additional object is provide a quick-connect fluid coupling in which latching members are captured in the coupling by the assembly thereof. 
     A further object is to provide a method for using the couplings disclosed herein. 
     These and other objects, features and advantages of the present invention will become apparent upon reference to the following description, accompanying drawings, and appended claims. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation of a supply drum (partially broken away) and umbilical delivery lines of a chemical extraction system and showing a side elevation of coded quick-connect fluid coupling in accordance with the present invention mounted on the drum and interconnecting the drum and the delivery lines. 
     FIG. 2 is an enlarged, longitudinal section of the preferred embodiment of the coded coupling shown in FIG. 1, such coupling including an extractor head providing one of the coupling members, a coded extractor drum insert providing the other coupling member, and a coded latching sleeve, the coupling members being shown in interfitted relationship but unlatched. 
     FIG. 3 is a view similar to FIG. 2 but with the coupling members interfitted, matched and latched. 
     FIGS. 4 a  and  4   b  are views similar to FIGS. 2 and 3 but respectively showing the extractor head and sleeve separated and uncoupled from the extractor insert. 
     FIG. 5 is a somewhat enlarged, longitudinal section of the extractor drum insert shown in FIG. 4 b.    
     FIG. 6 is a bottom plan view of the extractor drum insert taken from a position indicated by line  6 — 6  in FIG.  5 . 
     FIG. 7 is a somewhat reduced, longitudinal section of the extractor head shown in FIG. 4 a  but separated from the sleeve and without the delivery lines and poppet valve. 
     FIG. 8 is a top plan view of the extractor head taken from a position indicated by line  8 — 8  in FIG.  7 . 
     FIG. 9 is a somewhat reduced, longitudinal section of the coded latching sleeve shown in FIG. 4 a  but separated from the extractor head. 
     FIG. 10 is a bottom plan view of the coded latching sleeve taken from a position indicated by line  10 — 10  in FIG.  9 . 
     FIG. 11 is a side elevation of a coil spring employed in the present invention although enlarged from FIGS. 2 through 4 a.    
     FIG. 12 is a longitudinal section of either end portion of the coil spring shown in FIG.  11 . 
     FIG. 13 is a longitudinal section of a second no-coded embodiment of the quick-connect coupling of the present invention shown with the coupling members interfitted and latched. 
     FIG. 14 is a somewhat enlarged longitudinal section of only the extractor head of the coupling shown in FIG.  13 . 
     FIG. 15 is a top plan view of the extractor head shown in FIG.  14 . 
     FIG. 16 is a somewhat enlarged longitudinal section of only the sleeve of the coupling shown in FIG.  13 . 
     FIG. 17 is a bottom plan view of the sleeve shown in FIG.  16 . 
    
    
     DETAILED DESCRIPTION 
     A preferred embodiment of the coded fluid coupling of the present invention is generally indicated by the numeral  25  in FIGS. 1 through 4. The coupling is both a “quick-connect” and a “quick-disconnect” coupling. As is well known, such expressions as “quick-connect,” “quick-disconnect,” and “quick-release” couplings are commonly used to mean a coupling that has both quick-connecting and quick-disconnecting capabilities. Accordingly, the expression “quick connect” coupling is used herein to mean a coupling that is both quick to connect and quick to disconnect without repeating the word “disconnect” every time. 
     The subject coupling  25  (FIGS. 1 and 2) is particularly suited for use in conducting chemicals in the semiconductor industry where a variety of highly corrosive and incompatible chemicals are used. Such chemicals include ammonium hydroxide; hydrogen peroxide; and hydrofluoric, phosphoric, nitric, hydrochloride and sulfuric acids. These chemicals are typically stored in a fifty-five gallon drum, as  27 , as more fully illustrated in U.S. Pat. No. 5,108,015. The system employed in the semiconductor industry for supplying these chemicals may involve from fifteen to twenty of the drums with each drum containing a particular chemical. 
     The chemical extraction system or apparatus generally indicated in FIG. 1 includes a chemical supply or down tube or line  30  immersed in the chemical of one of the drums and extending up to the bung hole generally indicated at  32 . The extraction system also includes a chemical delivery line or hose  34  and an air or nitrogen feed line or hose  36 , each of which is connected to the coded quick-connect coupling  25 . An air indicator or sensor line or hose  38  is also connected to the coupling for a purpose to be described. The chemical delivery hose  34  extends from the drum to the work area of the semiconductor plant where the chemical in that drum is to be used. The hoses  36  and  38  respectively extend to sources of nitrogen and air under pressure, not shown. 
     As is well known, the hoses  34  and  36  associated with each chemical are suspended in an umbilical fashion above the drums  27  and are connected to their respective drums by a fluid coupling which in the present case is the coupling  25 . The hose  38  is similarly suspended and connected. The subject coupling allows for the quick and dependable disconnection and reconnection of these umbilical hoses to the down tube  30  when a depleted drum  27  is removed and a full drum replaces it, while ensuring that the chemical hoses for a particular chemical is connected to the corresponding drum containing that chemical. 
     The coded quick-connect coupling  25  (FIGS. 1 through 4) of the present invention in general includes an extractor head  50  connected to the delivery, feed and indicator hoses  34 ,  36 , and  38 ; an extractor drum insert  52  connected to the drum  27  and its down tube  30 ; a latch generally indicated at  54  for securing the extractor head and the extractor drum insert together when they are matched and interfitted; a poppet valve  56  that opens and closes upon connection and disconnection, respectively, of the extractor head and the extractor drum insert; and a key coding system  58  that ensures connection of the extractor head and delivery hose  34  for a certain chemical to the extractor drum insert and supply drum  27  containing that chemical. 
     The subject coded fluid coupling  25  is best described in detail by reference to FIGS. 2 through 4. The coupling is shown partially assembled in FIG. 2 with the extractor head  50  and the extractor drum insert  52  matched, interfitted and unlatched, that is, unlocked. FIG. 3 shows the coupling fully assembled, matched, interfitted and securely latched or locked. FIGS. 4 a, b  show the extractor head separated from the extractor insert but in condition to be thrust down on an extractor insert and coupled thereto if a match exists. 
     In describing the orientation of the extractor head  50  and drum insert  52  (FIGS.  2  through  4 ), a vertical orientation of the coupling  25  is assumed since this is its normal orientation in use. It will be understood, however, that the coupling is not limited to use in a vertical orientation, although such reference is convenient for descriptive purposes. Furthermore, the coupling is made almost exclusively of a corrosion-resistant, durable, and hard fluoropolymer plastic, such as “Teflon” PFA, that is perfluoroalkoxy, sold by the Dupont Corporation among others, or polyethylene. The only parts of the coupling that are not of this plastic material are the cores of coil springs, as explained below. Most of the parts of the coupling may be either molded or machined, although one of the major advantages of the subject coupling is that it may be readily molded rather than machined since the latter is more expensive. 
     The extractor drum insert  52  (FIGS. 5,  6 ) includes a lower, cylindrical, adapter fitting  66  having external threads  68  and providing a main or central fluid passageway  70  having a longitudinal central axis  72 . The drum insert also includes an upper male coupling member  74 , coaxial with the passageway and having a smooth external cylindrical surface  76 . A spider  78  is provided at the top of the male coupling member and, as is well known, provides a solid central portion surrounded by a plurality of openings allowing fluid material to flow therethrough and around the central portion. The adapter fitting also has a plurality of longitudinal air passages  80 , six in the disclosed embodiment, that are parallel to the central passageway and in substantially equally spaced relation around the central passageway. The main passageway connects to the down tube  30  (FIGS. 1,  2 ) for extracting the chemical from the drum  27 , and the air passages open into the drum above the level of the chemical therein. A gasket  82  seals between the drum and the insert. 
     The extractor drum insert  52  (FIGS. 5,  6 ) also has an annular key-coding flange  86  projecting radially outwardly from the adapter fitting  66  and terminating in an annular skirt  88 . The skirt has external threads  90  so that the insert is adapted for fitting into a bung hole, as  32 , of a different dimension from the adapter fitting  66 . The coding flange  86  has a plurality of coding holes  92  that are part of the key-coding system  58  of the present invention which will be subsequently described in more detail. At this point, however, it is to be noted (FIG. 6) that the coding holes include balancing holes  92   a  and  92   b  located in diametrically opposite positions on the coding flange and indexing holes  92   c ,  92   d , and  92   e  located in angularly spaced relation to each other and to the balancing holes  92   a  and  92   b , all of the holes being adjacent to the rim of the coding flange. In the subsequent description when the coding holes are generally referred to, the reference number  92  is used, but when a specific coding hole is referred to, the reference number  92  followed by a letter is used. 
     The latch  54  (FIG. 2) includes an inner latching ring  110  (FIGS. 5 and 6) projecting upwardly from and integral with the coding flange  86  in radially outwardly spaced, concentric relation to the male coupling member  74  and in radially inwardly spaced relation to the coding holes  92 . The inner latching ring has an annular, radially outwardly opening, latching groove  112  that is V-shaped in cross section thereby to provide outwardly, upwardly and downwardly extending, divergent or beveled groove surfaces. 
     The extractor head  50  (FIGS. 7,  8 ) includes a radial upper end wall  120  that has a large central recessed area  121 , an upper annular canopy  122  extending downwardly from the upper end wall, a cylindrical upper external surface  124  extending downwardly from the upper end wall and radially inwardly spaced from the canopy, and a cylindrical lower external surface  126  of a reduced diameter from the upper surface and extending downwardly therefrom to provide an upper radial shoulder  128 . The extractor head also includes an outer latching ring  130  that is a lower annular extension of the lower external surface but forms part of the latch  54 . 
     The latch  54  (FIGS. 2 through 4 a, b  and  7 ) of the present coupling  25  also includes a plurality of latching holes or bores  140 , eight in this disclosed first embodiment, that extend radially through the outer latching ring  130  of the extractor head  50 . These latching holes are equally angularly spaced about the outer latching ring so that with the eight holes in the disclosed embodiment, the holes are spaced approximately forty-five degrees apart. In addition, these holes have insides chamfers  141  that taper inwardly. That is, each hole has an inside diameter slightly less than its principal or outside diameter. The outer latching ring terminates in a lower radial end face  142 , and an annular radially outwardly opening retainer groove  144  is located in the outside face of the outer latching ring between the latching holes and the lower end face. 
     The extractor head  50  (FIGS. 7,  8 ) also has a lower female coupling member  150  providing a central, downwardly opening axial socket  152  defining a central longitudinal axis  154  of the extractor head. The female coupling member is equidistantly, radially, inwardly spaced from the outer latching ring  130  so as to define a downwardly opening latching annulus  154  therebetween. The female coupling member has an inner, annular sealing groove  158  facing into the socket and an outer annular sealing groove  160  facing into the latching annulus. An inner O-ring  162  (FIG. 3) is positioned in the inner groove, and an outer O-ring  164  is located in the outer groove. In this regard, it is to be noted that both of these O-rings are located in the extractor head and that no O-rings are located in the extractor drum insert, thereby facilitating molding of the insert. 
     The extractor head  50  (FIGS. 7,  8 ) also has a main or central fluid passageway  170  extending coaxially upwardly from and in fluid communication with a valve seat  172  that opens downwardly into the female coupling member  150  and connects to the delivery hose  34 . The main passageway opens upwardly in the center of the upper end wall  120  and has an upper threaded section  174 , a lower smooth section  176 , and a radial shoulder  178  between the upper and lower sections. 
     Still further, the extractor head  50  (FIGS. 7,  8 ) provides a threaded air return bore  184  offset from the main passageway  170  for connection to the feed hose  36 . Dual, longitudinally extending air passages  186  extend longitudinally through the extractor head in parallel relation to the main passageway and in offset relation to the air return bore. These air passages have upper ends connected to the air return bore and lower ends opening downwardly from the head through the female coupling member  150 . Also, the head has a threaded air indicator or sensor bore  194  on the opposite side of the main passageway from the air return bore. A single air passage  196  extends from the indicator bore longitudinally downwardly and thence radially of the head to an air vent  198  that opens through the lower external surface  126  of the head above the latching holes  140 . 
     The latch  54  of the subject coupling  25  (FIGS. 2 through 4) includes a plurality of spherical, uniformly sized, latching balls  200  each having a diameter greater than the minimum, but less than the maximum, diameter of the latching holes  140 . The balls are individually located in the latching holes for movement radially of the extractor head  50  between latching positions wherein portions of their spherical surfaces project into the latching annulus  154  (FIGS. 3 and 4) and retracted positions (FIG. 2) wherein the balls are entirely withdrawn into the latching holes so that none of the peripheries of the balls projects into the latching annulus. As previously mentioned, the latching holes are tapered so as to limit radial inward movement of the balls into the latching annulus. That is, only spherical segments of the balls are allowed to project into the annulus, whereas the balls are free to move outwardly in the latching holes so as to drop out of the extractor head, except that they are retained therein in a manner described below. 
     A coded latching sleeve  210  (FIGS. 2 through 4,  9 ,  10 ) is axially and rotatably, slideably mounted on the extractor head  50 . The sleeve includes an upper cylindrical section  212  slideably fitted around the upper cylindrical surface  124  of the head and radially outwardly spaced from the lower cylindrical surface  126  of the head. The sleeve also has a lower cylindrical section  218  slideably received on the lower external surface. A lower radial shoulder  220  between the upper and lower sections is in downwardly spaced, opposed relation to the upper radial shoulder  128 , and these shoulders together with the upper cylindrical section  212  and the lower external surface  126  define an annular pocket  214 . The sleeve also has an external, knurled actuating ring  216  (see also FIG. 1) projecting radially outwardly from the upper and lower sections  212  and  218  approximately midway between the upper and lower ends of the sleeve. The sleeve is thus axially slideable on the head into and out of unlatched and latched positions and is rotatable on the head into and out of matched and unmatched positions, as will be more fully described below. 
     The lower cylindrical section  218  of the latching sleeve  210  (FIGS. 2 through 4,  9 ,  10 ) has an inside, lower, cylindrical bearing surface  224  that slideably engages the lower cylindrical surface  126  of the extractor head  50  in their assembled condition. An annular venting passage  228  in the sleeve opens inwardly of this bearing surface and is registrable with the air vent  198  in the unlatched position of the sleeve. The sleeve also has a radially extending air vent  230  that communicates with the venting passage and opens outwardly from the sleeve just under the actuating ring  216 . Still further, the sleeve has a cylindrical recessed surface  232  of slightly greater diameter than the bearing surface and extending endwardly therefrom. The bearing and recessed surfaces are joined by a radial annular shoulder  234 . The sleeve also has a lower outer skirt  236  that projects downwardly from the lower end of the sleeve in radially outwardly spaced relation to the recessed surface. 
     The key coding system  58  of the subject coupling includes a coding ring  250  (FIGS. 2 through 4,  9 , and  10 ) that is integral with and projects downwardly from the lower cylindrical section  218  of the coded latching sleeve  210 . The recessed surface  232  is the inside surface of the ring and is in circumscribing, closely radially spaced relation to the lower external surface  126  of the extractor head  50  when the head and the sleeve are assembled. A plurality of coding pegs  258  project downwardly from the coding ring, with each peg being of a shape and size as to fit into a coding hole  92 . Circular pegs and holes are disclosed and preferred but other shapes may be used. The coding pegs include diametrically opposed coding pegs  258   a  and  258   b  and angularly spaced coding pegs, as  258   c , in equally, angularly spaced relation around the coding ring corresponding to the location of the coding holes and depending on whether a match is made between a particular extractor head  50  and a particular extractor drum insert  52 . The nomenclature and reference characters for the pegs correspond to that discussed in the description of the coding holes. 
     As referred to above, multiple coding combinations are provided by the key-coding system  58  of the subject invention (FIGS.  6  and  10 ). These combinations are achieved by varying the number, size, shape, and location, i.e., angular spacing, of the coding pegs  258  and the coding holes  92 . The disclosed preferred embodiment effects the desired combinations by varying the number and angular spacing of the holes and pegs. Although not used in the preferred embodiment, additional combinations can be achieved by varying the size and/or shape of the pegs and holes. In the preferred embodiment, the coding system uses circular pegs and circular holes of the same diameter, i.e., so that the pegs are capable of fitting in the holes when they are aligned and there is a complete match. The preferred coding system further involves using diametrically opposite balancing pegs  258   a  and  258   b  and corresponding diametrically opposite balancing holes  92   a  and  92   b  plus from one to sixteen more indexing pegs  258   c  through  258   r  and indexing holes  92   c  through  92   r , with adjacent pegs and adjacent holes being separated by twenty degrees. In this preferred system, sixteen different chemicals are accommodated by the described coding. For simplicity, only one indexing peg  258   c  and one indexing hole  92   c  are shown, but it will be understood that, depending on the particular code, there may be pegs and holes at each twenty-degree interval. A few other pegs and holes are indicated by dashed lines and reference characters pointing to cross-hatches where the pegs and holes are located. 
     For example, (FIGS. 6 and 9) key code  1  involves the two balancing pegs  258   a,b  and holes  92   a,b  and just one indexing peg  258   c  and indexing hole  92   c  spaced twenty degrees counterclockwise from the peg  258   a  and the hole  92   a ; key code  2  involves the two balancing pegs  258   a,b  and holes  92   a,b  and two indexing pegs  258   c,d  and indexing holes  92   c,d  spaced twenty degrees and forty degrees counterclockwise from the peg  258   a  and the hole  92   a ; key code  3  involves the two balancing pegs and holes and three indexing pegs  258   c,d,e  and holes  92   c,d,e  spaced twenty, forty, and sixty degrees counterclockwise from the peg  258   a  and the hole  92   a ; and so forth up to key code  16  using all eighteen pegs and holes. Although the key-coding examples as described above provide sixteen different combinations, it will be understood that many other combinations can be provided by varying the number, size, shape, and location of the coding pegs and the coding holes, as previously explained. 
     After the extractor head  50  and latching sleeve  210  are assembled, and the sleeve is pulled up on the head (FIGS.  2  and  3 ), a retaining ring  260  is fitted in the retainer groove  144  of the extractor head and projects radially outwardly from the retainer groove in opposed relation to the recessed surface  232  of the latching sleeve and provides an outside diameter that exceeds the inside diameter of the bearing surface  224 . The retaining ring has an endless metal core, preferably made of spring steel, and an external plastic coating, preferably made of Teflon or polyethylene, similar to the construction shown in FIGS. 11 and 12. Thus, the ring is extremely durable and tough, but it does have a measure of diametric elasticity. In other words, in its normally relaxed condition, the internal diameter of this retainer ring is approximately equal to the diameter of the retainer groove. For assembly of the retainer ring on the extractor head, the diametric elasticity of the ring allows it to expand just enough to increase its diameter to a size greater than the outside diameter of the lower cylindrical surface  126 , that is, the outer latching ring  130 . The retainer ring is thus expanded to slip over the lower end of the extractor head and then allowed to contract into the groove where it fits with its peripheral portion extending slightly outwardly from the lower cylindrical surface of the head, as seen in FIGS. 2 through 4 a.    
     A coiled actuator spring  270  (FIGS. 2-4,  11 ,  12 ) circumscribes the lower cylindrical surface  126  of the extractor head  150  and is positioned in the annular pocket  214  between the upper and lower radial shoulders  128  and  220  so as yieldingly to urge the latching sleeve  210  downwardly on the head  50  toward its latching position. The spring is compressible, however, to allow the sleeve to be moved upwardly on the head in a manner to be described more fully when discussing the operation of the subject coupling  25 . This spring also includes an internal metal core  272  (FIGS. 11,  12 ) preferably of spring steel and an external plastic cover  274  surrounding the metal core and having opposite open ends  276 . Plastic balls  278  are frictionally fitted in fluid-tight relation to the cover in the open ends thereof so as to isolate the metal core and preclude the entry of fluids into the cover into contact with the core. The cover and the balls are preferably made of Teflon or polyethylene. 
     The poppet valve  56  (FIGS. 2 through 4) includes a frusto-conical valve head  302  and upper and lower valve stems  304  and  306  extending respectively upwardly and downwardly from the valve head coaxially of the main passageway  170 . The valve also includes a tubular extension  308  connected to the upper valve stem and axially slideably fitted in the lower smooth section  176  of the main passageway. This tubular extension has a lower end wall with openings  310  providing communication therethrough. A valve spring  311  is positioned in the tubular extension and bears against a spring retainer  312  secured within the main passageway above the tubular extension for resiliently urging the valve head  302  into the valve seat  172 . The spring  311  is constructed like the actuator spring with an internal metal core and a plastic cover. 
     OPERATION AND METHOD OF USE 
     Before describing the operation and method of use of the subject coupling  25 , brief reference is made to the chemical extraction apparatus or system (FIG. 1) in which this coupling is especially suited for use. Thus, the down tube  30  is connected to the main passageway  70  of the extractor drum insert  52 , and the insert is threaded into the bung hole  32  of a fifty-five gallon drum  27  containing a chemical to be extracted. As such, the male coupling member  74  and the latching ring  110  extend upwardly from the drum, it being assumed at this point in the operation of the coupling that the extractor head  50  is not connected to the extractor drum insert (FIGS. 4 a  and  4   b ). As part of the chemical extraction system, the extractor head is, however, connected to the chemical delivery and feed hoses  34  and  36  with the delivery hose  34  connected to the main passageway  170  and the feed hose connected to the air return bore  184 . Also, as part of the subject invention, the air indicator hose  38  is connected to the air indicator bore  194 . Also, at this time, the poppet valve  56  is closed with the valve head  302  in sealing engagement in the valve seat  172 , being urged there by the valve spring  310 . 
     Also, at this initial stage, with extractor head  50  and drum insert  52  separated, the actuating spring  270  urges the coded latching sleeve  210  into its fully extended position on the extractor head  50 , as shown in FIG. 4 a . Several relationships between the sleeve and the head are to be noted in this position of the sleeve. First, the upper section  212  of the sleeve is spaced below the upper end wall  120  of the extractor head so as to permit subsequent upward travel of the sleeve on the head. Secondly, the venting passage  228  in the sleeve is not in registration with the inner air vent  198 . Next, the lower radial shoulder  220  of the sleeve is forced against the retaining ring  260  by the actuating spring  270 . In other words, the retaining ring prevents the sleeve from being pushed off the head by the actuating spring. It is thus understood why the retaining ring must have the durability and strength as described above since it must withstand the pressure of the spring  270  and preclude release of the sleeve; furthermore, repeated abutment of the shoulder  220  with the ring subjects the ring to considerable wear and tear. Also at this initial stage, the lower bearing surface  224  of the sleeve precludes outward movement of the latching balls  200  and thus captures them in the latching holes  140 . It will be recalled that the balls cannot fall from the holes inwardly of the sleeve because the inner diameters of the holes do not permit the balls to move therethrough. In addition, at this stage, the coding ring  250  and the coding pegs  258  project downwardly below the lower end face  142  of the extractor head. 
     It is now assumed that the extractor head  50  (FIGS. 1 and 2 through  4   a, b ) is to be connected to the extractor drum insert  52 . More broadly, in the context of the chemical extraction system, it is assumed that a delivery hose  54  for a particular chemical is to be connected to a drum  27  containing that chemical. It is further first assumed that the extractor head and the extractor drum insert to be connected are matching, thereby indicating that the particular chemical intended to be delivered in the hose  34  is in fact the chemical in the drum  27 . The key coding system  58  of the present invention thus will provide matching coding holes  92  and coding pegs  258 . If the key code illustrated in FIGS. 6 and 10 is being used (designated herein as Code  1 ), there are three coding holes and three coding pegs in matching locations respectively on the key coding flange  86  and the coding ring  250 . In other words, the code being used includes diametrically opposed balancing holes  92   a  and  92   b , diametrically opposed balancing pegs  258   a  and  258   b , one indexing hole  92   c  spaced twenty degrees counterclockwise from the balancing hole  92   a , as viewed looking up at the coding flange (FIG.  6 ), and one indexing peg  258   c  spaced twenty-degrees counterclockwise from the balancing peg  258   a , also as viewed looking upwardly at the coding ring (FIG.  10 ). 
     The extractor head  50  and coded latching sleeve  210 , as may be visualized in FIG.  1  and FIGS. 4 a , and  4   b  are manually grasped in the two hands of an operator and brought down over the extractor drum insert  52 . Preferably, the thumbs of the operator&#39;s hands bear downwardly on the upper end wall  120  of the extractor head and the other fingers are placed under the actuating ring  216  of the sleeve. When the male and female coupling members  74  and  150  are in adjacent axial alignment, the sleeve and the head are squeezed together to lift the sleeve relative to the head, from the FIG. 4 a, b  position to the FIG. 2 position. While so moved and held, the air port  230  and the air vent  198  are brought into registration so that air escapes from the air port and can be heard or even felt by an operator&#39;s hands on the ring  216 . Also at this time, the recessed surface  252  of the sleeve is opposite to the latching holes  140 , thereby freeing the latching balls  200  so they can move outwardly in their respective holes. 
     While squeezing the extractor head  50  and latching sleeve  210  together (FIG.  2 ), the extractor head (FIG. 2) is pushed down onto the extractor drum insert  52  so that the female coupling member  150  fits over the male coupling member  74  and the latching annulus  154  fits over and receives the latching ring  110 . With the sleeve pulled upwardly in this fully retracted position, the latching balls  200  are allowed to move outwardly and allow the latching annulus to move down over the latching ring into fully interfitted relationship. Whether or not the coding pegs  258  are exactly aligned with the coding holes  92  when the head is brought down onto the insert in this manner, the latching ring fully seats within the latching annulus. 
     While still squeezing the latching sleeve  210  and extractor  50  (FIG.  2 ), the operator allows the sleeve to move axially toward the extractor insert  52  whereby the coding pegs  258  engage the coding flange  86 , a position not shown, but easily visualized from FIG.  2 . At this time, it is possible, but not probable, that the coding pegs will be exactly aligned with the coding holes  92  and slip right into them. More likely, the operator will need to rotate the sleeve relative to the extractor head  50  and the extractor drum insert  52 , causing the coding pegs to slide circumferentially on the coding flange. Since the insert is secured to the drum  27 , the sleeve rotates easily relative to the insert. Since the extractor head is connected to the hoses  34 ,  36 , and  38 , it is maintained relatively stationary so that the sleeve can rotate relative to the extractor head. Such rotation occurs until the coding pegs  258  are exactly aligned with their corresponding coding holes  92 , assuming of course that the pegs and holes are matching as was earlier assumed in this example. At this time, the sleeve is forced downwardly by the actuator spring  270 , and the pegs are thrust into the holes (FIG.  3 ). Also, the bearing surface  224  moves downwardly over the latching holes  140 , pushing the latching balls  200  inwardly and their inner peripheries into the latching groove  112 . Moreover, as long as the expansive force of the actuating spring  270  remains on the sleeve, the bearing surface maintains the balls in the groove, whereupon the extractor head  50  and the drum insert  52  are maintained latched in coupled relationship, until manually released. 
     Also, when the latching ring  110  (FIGS. 2 and 3) fully seats in the latching annulus  154 , lower valve stem  306  engages the spider  78  and lifts the valve head  302  off the valve seat  172 . Opening the valve  56  establishes fluid communication from the down tube  30  (FIG.  1 ), through the male and female coupling members  74  and  150 , through the valve seat, into the main passageway  170  of the extractor head  50 , and eventually into the delivery hose  34 . At the same time, nitrogen or air is supplied from the feed hose  36  into the air return bore  184 , through the dual air passages  186  and into the manifold  320  that is formed between the extractor head and the extractor drum insert  52  in circumscribing relation to the male coupling member. From the manifold, air travels through the air passages  80  into the drum to replace the chemical withdrawn through the delivery hose and to prevent the formation of a vacuum. The O-rings  162  and  164  seal between the coupling members and prevent the escape of chemical or air. 
     Of prime significance, coupling of the extractor head  50  and the drum insert  52  is achieved without twisting or swiveling the head or the hoses  34 ,  36 ,  38  connected to it, although swiveling is accommodated if the natural position of the hoses forces an untwisting action. Only the latching sleeve  210  need rotate, but here, no time-consuming threading or unthreading is required. It is also significant that when the sleeve is released by the operator allowing interfitting of the coding pegs  258  and the coding holes  92  (FIG.  3 ), the air port  230  moves out of registration with the air vent  198  thereby to cut off the outflowing stream of air and indicating to the operator that, in fact, a matched interfitted relationship has been established between the extractor head  50  and the extractor drum insert  52 . Until the pegs drop into the holes, however, the port and vent remain aligned and air continues to escape, telling the operator that a match has not occurred. 
     If there is a mismatch between the extractor head  50  and the extractor drum insert  52 , and thus between the delivery hose  34  and drum  27 , the coding pegs  258  will not match the coding holes  92 . Therefore, rotation of the coded latching sleeve  210  will not result in an alignment of pegs and holes, and interconnection will be impossible. It is significant that the sleeve need be turned a maximum of only about three-hundred sixty degrees, and usually less, to test for a match, thus taking only a few seconds, whereupon if there is no match, the head and sleeve can be immediately lifted off the drum insert to close the poppet valve  56 . 
     When it is desired to uncouple the extractor head  50  from the extractor drum insert  52  (FIGS. 2-4 a ,  4   b ), the operator grasps the extractor head and the actuator ring  216  of the latching sleeve  210  with both hands, in the same manner as above described to connect the coupling  25 , thereby to squeeze the ring and the canopy  122  together against the urging of the actuator spring  270 . This squeezing action causes the recessed surface  252  (FIG. 2) to move into opposition with the latching balls  200  (FIG. 3) so that the balls are freed to move outwardly into their retracted positions. While continuing to squeeze the head and sleeve, the operator then lifts the head and sleeve thereby causing the upper bevel on the latching groove  112  to force the balls into their retracted positions. Such upward movement also lifts the lower valve stem  306  off the spider  78  allowing the valve spring  310  to close the poppet valve  56  and shut off the flow of chemical through the central passageways  70  and  170 . Any chemical that drips from the extractor head will fall through the spider or into the manifold  320  and drain into the drum  27  (FIG.  1 ). After the extractor head is free of the extractor insert (FIGS. 4 a ,  4   b ), the operator releases his grasp on the head and sleeve thereby allowing the actuator spring to move the sleeve relative to the head into the fully extended position of the sleeve with the shoulder  220  bearing against the retainer ring  260  (FIG.  4 ). It is again emphasized that no threading and not even any rotation of parts is required to uncouple the coupling  25 . 
     From the foregoing it will be understood that an improved fluid coupling  25  is disclosed having particular application in a chemical extraction system involving drums  27  of chemicals and delivery lines  34  suspended above the drums (FIG.  1 ). The subject coupling offers many advantages including improvement in the productivity and safety of dispensing a plurality of incompatible chemicals through different delivery lines from different drums in a manufacturing process; the dependable, yet quick connection and disconnection of only matched coupling members; and reduced manufacturing costs because of the ability to mold rather than machine the parts, although machining is possible. 
     A significant feature of the coupling  25  is that the parts are connected and disconnected without any threading or unthreading of the parts and without twisting of the lines or relative rotation of the coupling members and without regard to the relative rotational positions of the coupling members prior to or during interfitting thereof. In this regard, although the coupling does not require swiveling of its coupling members for connection or disconnection, such swiveling of the parts may occur and is accommodated during connection or disconnection without affecting the operation of the coupling. 
     The subject coupling  25  minimizes the time required dependably to connect and disconnect matched coupling members of a coded coupling or to determine that the coupling members are mismatched and will not couple; enables many different matching combinations; is balanced for dependable two-handed operation by a user; and allows an operator to confirm whether the coupling members are matched and interfitted or whether they are mismatched and not intermitted. 
     SECOND EMBODIMENT 
     A second embodiment of the subject coupling is shown in FIGS. 13 through 17 and is identified by the numeral  425 . In general, the coupling  425  differs from the coupling  25  in that the coupling  425  is not coded and thus is used where coding is unnecessary. The coupling  425  is similar to the coupling  25 , however, in the way in which the coupling  425  latches. The coupling  425  is preferably molded entirely of Teflon or polyethylene and, as shown assembled in FIG.  13 ), includes an extractor head  430 , an extractor drum insert  52  identical to that used with the first embodiment, and a latch generally indicated at  432 , including a latching sleeve  434 . Like the coupling  25 , the coupling  425  may be used in any orientation, but vertical is the most common and is thus a vertical orientation is used for descriptive convenience. 
     The extractor head  430  (shown separately in FIGS. 14 and 15) includes an upper adapter fitting  440  providing an outer, externally threaded cylindrical section  442  and an inner spider  444  defining an upper socket  446  therebetween, and a lower female coupling member  448  providing a lower socket  450 . The adapter fitting thus accommodates connection to a standard dispensing head, not shown, which in turn is connected to an umbilical dispensing hose. Suitable inner and outer O-rings  452 ,  454 , and  456  (FIG. 13) seal between the dispensing head and the adapter fitting. The adapter fitting has a main fluid passageway  458  and an air return passage  459 . 
     The adapter fitting  440  (FIGS. 14 and 15) has an external cylindrical smooth surface  460  below external threads  462 . An annular wall  464  extends radially outwardly from the surface  460 , and an annular outer latching ring  466 , which is part of the latch  432 , extends axially downwardly from the wall, terminating in a radial end face  468 . For a purpose to be described, a stop lug  470  extends upwardly from the annular wall  464  adjacent to the rim of the wall. 
     The outer latching ring  466  (FIGS. 14 and 15) is radially outwardly spaced from the female coupling member  448  thereby to define an annular downwardly opening latching annulus  474  therebetween. The ring has a plurality of latching holes  476  drilled therein in equally angularly spaced relation to each other circumferentially of the skirt. These holes are like the latching holes  140  of the first embodiment, but in this second embodiment, only four holes are provided spaced ninety degrees apart. As with the first embodiment, however, the invention is not limited to any particular number of holes, although eight are preferred in the first embodiment and four are preferred in this second embodiment. 
     Like the latching holes  140 , the latching holes  476 FIGS. 14 and 15) having inner frusto-conical chamfers that taper radially inwardly of the outer latching ring  466  whereby the  432  also includes spherical latching balls  480  (FIG. 13) of uniform diameter like the balls individually placed in the latching holes, with each ball having a diameter greater than the inner or minimum diameter of the latching holes but less than the principal or outer diameter, i.e., maximum diameter, of the holes. Each ball is thus movable between a latching position (FIG. 13) wherein a segment of its periphery projects into the latching annulus  474  and a retracted position (not shown, but similar to FIGS. 2 and 4 a  ) wherein the peripheral segment is withdrawn into its hole. The female coupling member  448  (FIG. 14) has annular inside and outside sealing grooves  486  and  488  respectively facing into the socket  450  and the latching annulus  474 . The inside groove receives an inside O-ring  490  and the outside groove receives an outside O-ring  492 . 
     The latching sleeve  434  (shown assembled in FIG. 13 but separately in FIGS. 16 and 17) which is part of the latch  432 , has an upper annular radial shoulder  512  that provides a top outside surface  514 , an inside underneath surface  516 , and a cylindrical neck  518 . An annular resiliently flexible lip  519  extends radially inwardly from the neck. A cylindrical skirt  520  depends from the shoulder and has an eternal knurled surface  522 , an annular internal surface  524 , and a radial end wall  526 . The internal surface (FIGS. 16 and 17) of the skirt has a plurality of arcuate latch recesses  530 , equal in number and spacing to the latching holes  476 . Each latch recess preferably subtends an arc of about forty degrees, although this angle is not critical as will be subsequently understood. Each of these recesses extends axially of the skirt from an upper shoulder  532  to the end wall  526 . 
     The latch recesses  530  (FIGS. 16 and 17) are thus separated by a plurality of arcuate bearing surfaces  534  that are portions of the internal annular surface  524  of the skirt  520 . As a result and as best seen in FIG. 17, the inside radius of the skirt at each latch recess  530  is greater than the inside radius of the skirt at the bearing surfaces. Each recess has a radial depth that varies from zero at its ends to a maximum at its center, such maximum depth being less than the diameter of each latching ball  480  but greater than the effective depth of the latching grove  112  in the outer latching ring  110 , that is, the distance that the projecting segment of each ball  480  extends out of each hole  476  into the latching groove  112 . 
     The underneath surface  516  (FIGS. 16 and 17) of the upper shoulder  512  of the latching sleeve  434  has a downwardly opening arcuate limit slot  540  therein. In the disclosed second embodiment, this slot subtends and arc of about sixty degrees circumferentially of the shoulder between its ends  542 . As will be seen in FIG. 17, this slot extends from about the midpoint of one latch recess about to the adjacent end of the adjacent latch recess. 
     In order to assemble the latching sleeve  434  and the extractor head  430  (FIG.  13 ), the latching balls  480  are placed in their latching holes  476 , and the skirt  520  is fitted down over the extractor head with the stop lug  470  aligned with the limit slot  540 . In so doing, the outer cylindrical section  442  fits through the neck  518 , the lip  519  resiliently yielding to allow the section  442  to pass through; actually, the lip yields and slips from one thread to the next as it snaps down below the externally threaded section  442  into the position shown in FIG.  13 . It is to be noted that whereas FIG. 13 shows the assembled sleeve and head coupled to the extractor insert, what is being described at this point is only the assembly of the sleeve and head; it is 
     In this assembled condition of the latching sleeve  434  and the extractor head  430  (FIG. 13) several relationships are to be noted: the stop lug  470  is received in the limit slot  540 , the latching holes  476  and their latching balls  480  are either opposite the latch recesses  530  or the bearing surfaces  534 , depending on the relative angular positions of the sleeve and head; the end wall  526  of the sleeve is in the same plane as the end face  468  of the inner latching ring  110 ; and the lip  519  is in adjacent axially downwardly spaced relation to the outer section  442  of the adapter fitting  440 . assumed that the coupled state of the members  448  and  74  has not yet occurred. 
     In order to retain this assembled condition (FIG. 13) of the sleeve  434  and the head  430 , a flat, resiliently diametrically expandable, radially split, lock washer  550  is spread apart, fitted over the outer section  442 , rested on the radial wall  464 , and allowed to contract around the cylindrical surface  460  between the outer section  442  and the lip  519  and the shoulder  512 . By rotating the sleeve relative to the head through an angle of about sixty degrees, i.e., the length the limit slot  540 , or about ⅙ th  of a turn, the sleeve is moved between latching and unlatching positions. In its latching position, the bearing surfaces  534  are opposite to the latching holes  476 , engage the latching balls  480 , and force them inwardly of their holes into their latching positions, as shown in FIG.  13 . In its unlatching position, the latch recesses are opposite to the latching holes and allow the balls to move outwardly into the recesses and thus into their unlatching positions, a position not shown in the drawings but similar to FIG.  2  and believed to be understood. 
     When it is desired to connect the extractor head  430  to the drum insert  52  (FIG.  13 ), the latching sleeve  434  is first turned on the head into its unlatched position. It is, of course, understood that the extractor head is connected to a dispensing head and hoses not shown. The assembled head and latching sleeve are then brought down over the insert (visualized in FIG.  13 ), and the inner latching ring  110  is fitted in the latching annulus  474  with the lower socket  450  of the female coupling member placed down over the male coupling member  74 . The inside diameter of the inside O-ring  490  is slightly less than the outside diameter of the male coupling member so that the parts must be pressed tightly together to snap and seat the male coupling member into the female coupling member and the inner latching ring into the latching annulus. When thus assembled, an annular manifold  560  is defined between the extractor head and the drum insert circumscribing male coupling member so as to provide communication from the air return bore  459  to the air passages  80 . Communication is also established between the passageways  70  and  458 . It is to be noted that the extractor head and drum insert can be interfitted irrespective of their relative rotational positions so that no rotation of the head is required to couple it to the insert, although swiveling of the head is accommodated if forces on the head require it. 
     After the extractor head  430  and the drum insert  52  are thusly interfitted, the latching sleeve  434  is rotated clockwise (from the top) about sixty degrees or one-sixth of a turn into its latching position (FIG.  13 ). Such rotation causes the bearing surfaces  534  to push the latching balls  480  into the latching groove  112  thereby to latch the coupling members  74  and  448  together. Rotation of the sleeve on the head is limited by the stop lug  470  engaging one of the ends  542  of the limit slot  540  so as to insure alignment and to indicate t and to indicate to the operator that latching has been achieved. 
     To uncouple the extractor head  430  from the drum insert  52 , the latching sleeve  434  is rotated counterclockwise (from the top) about sixty degrees or one-sixth of a turn into its unlatched position (not shown). Again, engagement of the stop lug  470  with the opposite end  542  of the limit slot indicates to the operator that the unlatched position is reached. As such, the recesses  530  are opposite to the holes  476  and balls  480 , thereby allowing the balls to move into the recesses and withdraw into their holes. The head can then be lifted off from the insert. 
     It will be understood from the foregoing that a very simple, yet highly effective, fluid coupling  425  has been provided. The coupling enables the extractor head  430  to be coupled and latched, and unlatched and uncoupled, without requiring any rotation of the extractor head relative to the drum insert. Yet the coupling allows swiveling of the head relative to the insert and the sleeve if necessary. Moreover, this coupling and uncoupling and latching and unlatching is achieved without any threaded or unthreading of the parts. The coupling can be entirely and effectively molded out of chemically-resistant plastic as described thus minimizing manufacturing costs. In addition, the head and sleeve are compatible with the same drum insert that is used with the multiple delivery lines involved with the first embodiment. 
     Although preferred embodiments of the present invention have been shown and described, various modifications, substitutions and equivalents may be used therein without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.