Abstract:
The torque confirmation fitting is used for coupling one section of tubing to another and includes a fitting body, a fitting nut, and a torque confirmation portion. The fitting body has a nose section that supports an end of one of the sections of tubing. The torque confirmation portion has a collar portion and one or more prongs. The fitting nut is operably joinable to the fitting body and engageable with the torque confirmation portion. To operate, the non-supported end of the tubing is inserted through the torque confirmation portion and the fitting nut. The fitting nut is then joined to the fitting body and in doing so engages the torque confirmation portion. The continued joining of the fitting nut to the fitting body causes the prong of the torque confirmation portion to provide a visual indication that the fitting nut has been sufficiently, tightly joined to the fitting body.

Description:
FIELD OF THE INVENTION 
     The present invention relates to plastic fittings for joining sections of plastic tubing, and, more particularly, to plastic fittings that provide an indication of achieving a certain torque level upon the tightening of the fitting. 
     BACKGROUND OF THE INVENTION 
     Numerous industries use metallic tubes and fittings of copper, stainless steel, and steel where connection of high strength and integrity are needed. Metallic plumbing is very suitable in many applications. However, in certain industries, the fluids conveyed may attack metal components and the metal can contaminate the conveyed fluids, i.e., the semiconductor processing industry. Highly inert fluoropolymers may be utilized for the fittings, tubing, and components in such applications, for example, polytetrafluoroethylene (PTFE), and perfluoroalkoloxy (PFA). To maintain a clean and non-hazardous environment, it is essential that the fittings provided for coupling to sections of tubing are not easily unintentionally disconnected and that the tubing/fitting interface maintains its integrity even under mechanical stress. Various types of fittings are known in the art for these purposes. 
     One standard type of fitting, known as a FLARETEK® fitting, available from the assignee of this application, provides for a fitting body, with an elongate nose with a tapered or rounded tip, and a fitting nut that is attachable thereto. A section of tubing is placed with a nut thereon in engagement with the elongate nose section and the fitting nut is rotated and drawn onto the fitting body, pinching the flared tubing end between the nut and the fitting body. Although fluoropolymer fittings are very robust and have excellent performance characteristics, for many applications they are not as hard as traditional metal fittings and not as common. Thus, particularly for an infrequent user, providing the proper tightening torque is problematic. Over tightening of the fitting nut to the fitting body may damage the fitting nut, tubing, and/or fitting body. For example, threads may be stripped under substantially less torque than in similarly sized metal fittings. The damage may not be detected until materials are flowing through the various tubing sections and a potentially hazardous leak occurs. Under torqueing can fail to provide an adequate fluid seal and mechanical connection. 
     Thus, there is a need for a fluid flow fitting that provides a fitting assembler with notification that the fitting nut has been sufficiently tightened so that an optimum seal and mechanical connection has been created between fitting body, tubing end, and fitting nut. This notification may be visual, audible, and/or by touch means providing an instant and easily identifiable warning. 
     SUMMARY OF THE INVENTION 
     The needs described above are met by the torque confirmation fitting of the present invention. The torque confirmation fitting is used for coupling to a tubing end having a fluid flow duct and generally includes a fitting body, a fitting nut, and a torque confirmation means. In a preferred embodiment, the fitting body has a nose section that receives a flared end of the tubing. The torque confirmation means has a collar portion and one or more prongs. The fitting nut is rotatably joinable to the fitting body and cooperates with the torque confirmation portion. The end of the tubing with the nut and the torque confirmation thereon is engaged with the fitting body. The fitting nut is then rotatably joined to the fitting body and in doing so engages the torque confirmation portion. The continued tightening of the fitting nut to the fitting body, in the preferred embodiments, causes the prong of the torque confirmation portion to provide a visual indication that the fitting nut has been sufficiently and/or optimally tightened to the fitting body. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a torque confirmation fitting of the present invention. 
     FIG. 2 is an end view of the torque confirmation fitting of FIG.  1 . 
     FIG. 3 is a cross-sectional view of the torque confirmation fitting taken along line  3 — 3  of FIG.  2 . 
     FIG. 4 is a detailed cross-sectional view of the torque confirmation fitting, indicated as detail area B on FIG.  3 . 
     FIG. 5 is a perspective view of a torque confirmation portion of the present invention. 
     FIG. 6 is a perspective view of an alternative embodiment of the torque confirmation fitting of the present invention. 
     FIG. 7 is an view of the torque confirmation fitting of FIG.  6 . 
     FIG. 8 is a cross-sectional view of the torque confirmation fitting taken along line  8 — 8  of FIG.  7 . 
     FIG. 9 a  is a detailed cross-sectional view of the torque confirmation fitting, indicated as detail B on FIG.  7 . 
     FIG. 9 b  is detailed cross-sectional view of the torque indicating elements and torque indicator windows. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Each embodiment of the torque confirmation fittings of the present invention, described herein, provides for quick assembly of the fitting to tubing end portion and provides a verification of proper tightening of the fitting. The tubing end portion may be part of a section of tubing or may be a portion of a component such as valve, filter, pump, another fitting or other fluid handling component. 
     A first embodiment  100  of the torque confirmation fitting  10  is depicted in FIGS. 1-4. As shown, torque confirmation fitting  10  generally comprises a fitting body, or first coupling means  112 , a fitting nut, or second coupling means,  114  and torque confirmation portion  116 . Referring specifically to FIGS. 1 and 2, fitting nut  114  and torque confirmation portion  116  are shown secured to fitting body  112 . Those exterior portions of fitting nut  114 , torque confirmation portion  116 , and fitting body  112  not concealed by the securement of fitting nut  114  and torque confirmation portion  116  to fitting body  112  may be appreciated herewith. Specifically, the non-concealed portion of fitting body  112  is generally cylindrical in shape and preferably incorporates one or more planar surfaces  118  for easier grasping of fitting body  112  during assembly. 
     The non-concealed portion of the exterior of fitting nut  114  has a generally cylindrical body  115  with a plurality of winged extensions  120 , facilitate grasping and turning of fitting nut  114  during assembly of torque confirmation fitting  10 . Each winged extension  120  generally comprises an enlongate, substantially flat top face  122  and a pair of elongate, substantially parallel and planar side faces  124  that extend substantially perpendicularly from the top face  122 . Further defining the exterior of fitting nut  114  are a plurality of elongate separator faces  126 , which are positioned between opposite side faces  124  of adjacent winged extensions  120 , and a pair of substantially parallel end faces  130 . 
     The non-concealed portion of torque confirmation portion  116  is defined by a plurality of prongs, or projecting means,  134  which extend beyond one of end faces  130  and surround a section of tubing  136  secured therein. Each prong  134  is separated from the other by a spacer portion  138  of torque confirmation portion  116 . 
     Referring now to FIGS. 3,  4 , and  5 , cross-sectional views of embodiment  100  of torque confirmation fitting  10  with the tubing end  139  secured therein are depicted. The cross-sectional views of FIGS. 3 and 4 help to further define those portions of fitting body  112 , fitting nut  114 , and torque confirmation portion  116  concealed in FIGS. 1 and 2, as well as the interior configuration of fitting body  112 , fitting nut  114  and torque confirmation portion  116 . As shown, fitting body  112  is preferably of a unitary configuration having a central bore  140  extending therethrough. The unitary configuration of fitting body  112  generally includes an outer ring portion  142 , an annular recessed portion  144  proximate outer ring portion  142 , a threaded exterior surface portion  146  proximate annular recessed portion  144 , and a recessed, tapered nose section  148 , proximate threaded exterior surface portion  146  and surrounding central bore  140 . 
     Fitting nut  114 , like fitting body  112 , is also preferably of a unitary configuration, and incorporates an inner nut portion  150 . Inner nut portion  150  of fitting nut  114  is preferably defined by a lower, threaded inner surface portion  152 , wherein the threads of threaded inner surface portion  152  are designed to interface with the threads of threaded exterior surface portion  146  of fitting body  112 . Inner fitting portion  150  is further preferably defined by an intermediate circumferential wall portion  154  and a distal circumferential wall portion  156 , both of which define bores  155  and  157 , respectively. Intermediate wall portion  154  and circumferential outer wall portion  156  are joined by a radial extender section  158 . The gap between the bore  157  and the tubing define an indicator window  159  indicated by dashed lines. 
     Referring to FIGS. 3,  4 , and  5 , torque confirmation portion  116  includes a collar portion  170  and plurality of torque indicating elements configured as prongs  134 , which are preferably integral with collar portion  170 . Collar portion  170  is preferably defined by a substantially cylindrical, lower face  172  may define an annular space  174  extending therethrough. Collar portion  170  is further preferably defined by a pair of substantially parallel radial side walls  176 , which extend perpendicularly between inner surface/bore  172  and an outer surface  178 . Substantially cylindrical upper face  178  is interrupted by a notch  180 . Notch  180  is defined by a first surface  182  and a second surface  184  that are joined to create a triangularly shaped recess. Notch  180  enables better flexing of collar portion  170  as prongs  134  are pressed radially inward when being inserted through fitting nut  114 . 
     Each prong  134  of torque confirmation portion  116  is preferably defined by a proximal portion  184  with a substantially, rectangularly-shaped cross-section, a shank portion  185 , a distal portion  186  with a substantially triangular cross-section and an annular recess  185 . 1 . Proximal portion  184  includes a radial face  188  on collar portion  170  as well as an outer surface  190  and a inner surface  192 . Distal portion  186  includes a inner surface  194  that extends angularly, e.g., 30 degrees, upward from inner face  192 . Distal portion  186  further includes an outer surface  196  that extends angularly, e.g., 50 degrees, between an extender section  198  and lower face  194 . 
     In securing embodiment  100  of torque confirmation fitting  10  to tubing  136 , the pre-flared end  139  of tubing  136  is oriented confronting tapered nose section  148  of fitting body  112  and is placed thereon typically with the nut and torque confirmation portion  116  positioned on the tubing  136  slightly offset from the tubing end  139 . Torque confirmation portion  116  is then moved proximate the flared portion of tubing  136 . The fitting nut  114  with the torque confirmation portion  116  is slid towards fitting body  112  until threaded side portion  146  of fitting body  112  engages with fitting nut  114 . Fitting nut  114  is manually rotated such that the threads  146 . 1  of fitting body  112  and threads  146 . 2  of the fitting nut  114  act to draw fitting nut  114  axially towards outer ring portion  142  of fitting body  112 . 
     As fitting nut  114  is axially drawn towards outer ring portion  142 , prongs  134  of torque confirmation portion  116  wedged under bore  157  and are flexed slightly inward and radially compressed by inner fitting portion  150  of fitting nut  114 , the flexing ability enhanced by virtue of notch  180 , and are edged closer to the distal end faces  130 . Simultaneously, collar  170  of torque confirmation portion  116  is acting to pinch the pre-flared end of tubing  136  to tapered nose section  148  of fitting body  112 . At a predetermined position of the fitting nut  114  on the fitting body which corresponds to a specific torque level, the drawing of fitting nut  114  towards fitting body  112  causes upper wall portion  156  of fitting nut  114  to push past the prongs whereby the prongs  134  snap on to flex radially outward at distal end face  130 . The outward flexing of prongs  134 , in a preferred embodiment, make a snapping sound providing an audible indication to the user that the proper torque of fitting nut  114  to fitting body  112  has been achieved. The snapping may be sensed by touch particularly where the nut is being manually tightened by hand or even where a wrench type tool is utilized. Moreover, the extension of the distal portion  186  of the torque confirmation portion through the indicator window  159  provides visual indication of proper positioning of the nut and proper torque. Further, the outward flexing of prongs  134  acts to substantially lock fitting nut  114  into position. The torque indicating elements thus are locking members. Further, the upward flexing, the locking, provides the user with notice that fitting nut  114  has been sufficiently tightened to fitting body  112  such that an adequate or optimal seal has been created between tapered nose section  148  of fitting body  112  and the pre-flared end of tubing  136  and collar  170  of torque confirmation portion  116 . Specifically, the collar  170  is axially loaded and compressed, said compression facilitated by notch  180 , and the shoulder  139 . 1  of the flared end is axially compressed. The angle or taper of the shoulder  139 . 1  and nose section  148  provides a component of radial compression at the seal interface  139 . 2 . Thus, torque confirmation portion  116  and the window  159  provide means for indicating proper torque of the nut. 
     Referring to FIG. 1, structure on the prongs, such as on the inward face  193  of the distal portion of the torque confirmation portion can engage with structure  191  on the nut, for example, a multiplicity of grooves on the distal end face to securely lock the nut in place on the fitting at the appropriate position and/or optimal tightening level. 
     The predetermined amount of torque at which the torque indicating elements  134  provide indication, i.e. snap out, can be adjusted by varying the configuration of torque confirmation portion. Distal circumferential wall portion  156  define an annular inwardly extending collar  156 . 1  which has a length 1 1 . The torque confirmation portion  134  has an annular recess  185 . 1  which has a length 1 2 . 1 1  may be sized to be slightly greater than 1 2  such that the collar portion must be axially compressed to allow the annular recess  185 . 1  to fully engage the annular inwardly extending collar  156 . 1 . Such compression is controlled by the size and positioning of the notch  180 . Thus by providing alternate collars, that have different recess lengths 1 1  and different collar  170  configurations, the predetermined torque can be controlled. 
     An alternative embodiment  200  of torque confirmation fitting  10  is depicted in FIGS. 6,  7 ,  8 ,  9   a,    9   b.  As shown, torque confirmation fitting  10  generally comprises a fitting body (or first coupling means)  212 , a fitting nut (or second coupling means)  214  and a torque confirmation portion  216 . Referring specifically to FIGS. 5 and 6, fitting nut  214  and torque confirmation portion  216  are shown secured to fitting body  212 . Those exterior portions of fitting nut  214 , torque confirmation portion  216 , and fitting body  212  not concealed by securement of fitting nut  214  and torque confirmation portion  216  to fitting body  212  may be appreciated herewith. Specifically, the non-concealed portion of fitting body  212  is generally cylindrical in shape and preferably incorporates one or more planar surfaces  218  for easier grasping of fitting body  212  during assembly. 
     The non-concealed portion of the exterior of fitting nut  214  is also generally cylindrical in shape but is provided with a plurality of winged extensions  220 , which provide for easier grasping and turning of fitting nut  214  during assembly of torque confirmation fitting  10 . Each winged extension generally comprises an elongate, substantially planar top face  222  and a pair of elongate, substantially parallel and planar side faces  224  that extend substantially perpendicularly from planar top face  222 . Further defining the exterior of fitting nut  214  are a plurality of elongate separator faces  226 , which are positioned between opposite side faces  224  of adjacent winged extensions  220 , and a pair of substantially parallel end faces  230 ,  231 . The distal end face  231  preferably includes a plurality of indicator windows configured as apertures  232  that are designed to receive torque indicating elements, configured as prongs, or projecting means,  234  of torque confirmation portion  216 ; only the rounded tips  235  of prongs  234  are visible in FIGS. 1 and 2. A section of smaller diameter tubing  236  is shown extending from fitting nut  214  while a section of larger diameter tubing  237  is shown by hidden lines within fitting body  212 . 
     Referring now to FIGS. 8 and 9, cross-sectional views of embodiment  200  of torque confirmation fitting  10  are depicted. The cross-sectional views of FIGS. 7 and 8 help to further define those portions of fitting body  212 , fitting nut  214 , and torque confirmation device  216  concealed in FIGS. 5 and 6, as well as the interior configurations of fitting body  212 , fitting nut  214 , and torque confirmation portion  216 . As shown, fitting body  212  is preferably of an integral configuration having a central bore  240  extending therethrough. The end of the fitting body opposite the nut may have threads, other connection means, or be attached to or integral with devices such as valves or other fluid handling components or equipment. The integral configuration of fitting body  212  generally includes an outer ring portion  242 , which has grasping surfaces  218  for a wrench. The ring portion can also serve as a stopping ring preventing over travel of fitting nut  214 , a threaded side portion  246  proximate annular recessed portion  244 , and a recessed, tapered nose section  248 , proximate threaded exterior portion  246  and surrounding central bore  240 . 
     Fitting nut  214 , like fitting body  212 , is also preferably of a integral configuration, and incorporates an inner fitting portion  250 . Inner fitting portion  250  of fitting nut  214  is preferably defined by a threaded inner portion  252 , wherein the threads of threaded inner portion  252  are designed to interface with the threads of threaded exterior portion  246  of fitting body  212 . Inner fitting portion  250  is further preferably defined by an intermediate wall portion  254  and a distal wall portion  256 , both of which are generally planar surfaces. Intermediate wall portion  254  and distal wall portion  256  are joined by an extender section  258 . As indicated previously, fitting nut  214  is further defined by a plurality of indicator windows configured as apertures  232 , which are positioned above distal wall portion  256  and extend from extender section  258  through to end plate  230 . Apertures  232  are of a diameter to accommodate prongs  234 . 
     Torque confirmation portion  216  preferably includes a collar portion  270  and a plurality of prongs  234 , which are preferably unitary with collar portion  270 . Collar portion  270  is preferably defined by a substantially planar lower face  272  that surrounds an aperture  274  extending therethrough. Collar portion  270  is further preferably defined by an elongate side wall  276  and a shortened side wall  278 . Elongate side wall  276  extends between lower face  272  and an upper face  280 , which extends the length of prong  234 . Shortended side wall  278  extends between lower face  272  and a lower surface  282  of prong  234 . Thus, each of prongs  234  is preferably cylindrical in shape having rounded tip  235  and an upper point and lower point of the cylinder defined by upper face  280  and lower surface  282 , respectively. Upon insertion of prong  234  through aperture  232 , notch engaging portion  264  extends through the indicator window providing a visual indication of proper tightening. 
     The apertures have a diameter d 1  and the tip  235  of the prongs  234  have a diameter d 2  which may be appropriately sized with d 1  less than d 2  torque. The prongs  234  may have a locking means configured as an annular recess  235 . 1 . 
     The predetermined torque of a fitting can be varied by selecting appropriately sized diameters d 1  and d 2 . 
     In securing embodiment  200  of torque confirmation fitting  10  to tubing  236 , the pre-flared end  285  of tubing  236  with the nut and torque confirmation portion thereon, is oriented facing tapered nose section  248  of fitting body  212  and is placed thereon. Fitting nut  214  is engaged with the fitting body  212  with the apertures  232  aligned with prongs  234  of torque confirmation portion  216 . Fitting nut  214  is then preferably manually rotated such that the threads of fitting body  212  and fitting nut  214  act to axially draw fitting nut  214  towards outer ring portion  242  of fitting body  212 . 
     As fitting nut  214  is drawn towards outer ring portion  242 , prongs  234  are driven through apertures  232  of fitting nut  214 . Simultaneously, collar  270  of torque confirmation portion  216  is acting to pinch the pre-flared end of tubing  136  to tapered nose section  248  of fitting body  212 . Eventually, the drawing of fitting nut  214  towards fitting body  212  causes tip  235  of prong  234  to extend beyond end plate  230  out the indicator window providing a visual signal indicating to the user that fitting nut  214  has been tightened sufficiently to fitting body  212  such that a seal has been created between tapered nose section  248  of fitting body  212 , the pre-flared end of tubing  236 , and collar  270  of torque confirmation portion  216 . Specifically, a pinch point has been created between tapered nose section  248 , tubing  236 , and collar  270  and effected a seal thereby. 
     It should be noted that the torque confirmation fittings  10  described herein may be utilized to secure pre-flared tubing or, alternatively, the torque features of the fittings  10  may be incorporated into a self-flaring fitting that is designed for use with non-flared tubing. Such self-flaring fittings are described in co-pending U.S. patent application Ser. No. 09/589,690, entitled “Self-Flaring Plastic Fittings” with the same inventors, the same filing date, and the same owner as the instant application. Said application is incorporated herein by reference. 
     The present invention may be embodied in other specific forms without departing from the spirit of the essential attributes thereof; therefore, the illustrated embodiments should be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.