Abstract:
A fitting comprises a body with a generally flat first face, a gland with a generally flat second face, and a collet assembly adapted to be squeezed onto the outside of the conduit. A nut surrounds the gland and is adapted to engage the body, to force the first and second faces into sealing engagement with each other and to force the collet assembly into sealing engagement with a conduit and with an internal passage in the gland. When the nut is an advanced position, it engages the body, transmitting an axially compressive force to the first collet and pressing the forward end face of the gland against the rear end face of the body. When the nut is a retracted position, it has its forward end face no farther forward than the plane of the forward end face of the gland.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates fittings for conduits such as tubes and pipes, and in particular to a flare-less or grip type fitting with a face seal to join a conduit to another component. 
       BACKGROUND 
       [0002]    Flare-less and grip-type fittings use one or two collets (or ferrules) and a nut that cooperate with a body. A leak-proof seal is obtained as the collets are tightened onto a conduit through the axial thrust provided by the nut. The front collet provides a leak-proof seal when the nut and collets are drawn up a specified number of turns. The rear collet grips the conduit to prevent pull off. Other similar fittings use a single collet, and work in much the same way. 
         [0003]    The body of a fitting is adapted not only to accept the conduit and nut from one end, but to be connected to another component at its opposite end. For this reason the body may have, for example, external or internal threads to join it to the other component, or a nipple for connecting it to a hose or a other conduit, or a fitting for a flare union. 
         [0004]    In order to assemble a flare-less or grip-type fitting, it is necessary to insert an end portion of the conduit through the nut, through the collets, and into the body prior to tightening the nut. Once the collets are tightened onto the conduit, they cannot be removed easily, and disassembly of the fitting requires the conduit to be pulled out axially from the fitting body. This fact can make the use of flare-less and grip-type fittings difficult or impossible in some applications. For example, where a conduit must bend sharply, it may be impossible to install the conduit into mutually perpendicular fittings without bending and damaging the tube. 
       SUMMARY 
       [0005]    The present application discloses a fitting for connecting a conduit to another component. The fitting combines a collet-seal with the conduit and an O-ring face seal for connecting to the other component. The fitting comprises a body adapted to connect to the other component. The body has a passage therethrough for carrying a fluid, and the passage terminates at a generally flat first face transverse to the passage. The fitting also comprises a gland having a passage therethrough for carrying a fluid, and the passage through the gland terminates at a generally flat second face transverse to the passage. The first and second faces are proportioned to be positioned in sealing engagement and with the passage through the gland in fluid communication with the passage through the body. The gland has an internal passage for receiving an end portion of the conduit. The fitting further comprises a collet assembly proportioned to surround the conduit and adapted to be squeezed into sealing engagement with the outside of the conduit. A nut surrounds the gland and is adapted to engage the body, to force the first face and second face into sealing engagement with each other and to force the collet assembly into sealing engagement with the conduit and the internal passage in the gland. The nut is movable between advanced and retracted positions. When the nut is in the advanced position, it engages the body, transmitting an axially compressive force to the first collet and pressing the forward end face of the gland against the rear end face of the body. When the nut is in the retracted position, it has its forward end face no farther forward than the plane of the forward end face of the gland. The collet assembly and the gland may be captured at least partially within the nut. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    While the specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed that the same will be better understood from the following description taken in conjunction with the accompanying drawings in which: 
           [0007]      FIG. 1  shows a fitting having features disclosed in this application including I&#39;m not engaging a body to seal a gland to the body; 
           [0008]      FIG. 2  is a cross sectional view of the fitting illustrated in  FIG. 1  but showing the not backed off the body so the body and gland may be separated; 
           [0009]      FIG. 3  is an exploded view of the fitting of  FIG. 1 ; 
           [0010]      FIG. 4  is a cross-sectional view of the fitting of  FIG. 1  before it has been made up; 
           [0011]      FIG. 5  is a cross-sectional view of the fitting of  FIG. 4  after it has been made up; 
           [0012]      FIG. 6  is a cross-sectional view of the fitting similar to that shown in  FIGS. 1-5  but having a single collet. 
           [0013]      FIG. 7  is a cross-sectional view of the fitting similar to that shown in  FIGS. 1-5  but having a different collet; 
           [0014]      FIG. 8  is a cross-sectional view of a fitting similar to that shown in  FIG. 4  but having an alternate structure for capturing a collet assembly and gland within a nut; and 
           [0015]      FIG. 9  is a cross-sectional view of a portion of a fitting similar to that of  FIG. 4  but having a second alternate structure for capturing a collet assembly and gland within a nut. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    The fitting  10  shown in  FIG. 1  is adapted to connect a conduit  12  to another component  14 . To facilitate the description which follows, the terms “forward” and “rearward” or “front” and “rear” are used, but they are not intended to be limiting in any way. As viewed in  FIG. 1 , the rear of any piece is to the left, while the front is to the right, but this convention is intended only to make this description easier to read and understand. 
         [0017]    The conduit  12  may be what is termed the “tube”, a “pipe”, or any other type of device for carrying fluid under pressure. The fluid may be a liquid or gas, a combination, or even a slurry. The fluid may be at a higher or lower pressure than ambient. 
         [0018]    The component  14  can be any device or object to or from which fluid from the conduit  12  is to flow. As illustrated in  FIG. 1 , the fitting  10  includes a body  16  with a threaded end portion  18  which can be screwed into the component  14 . However, the body  16  may be connected to the component  14  by other means, or many the integrally formed with it. 
         [0019]    The fitting  10  includes the body  16 , a gland  28 , and a nut  30 . The body  16  includes a central passage  20  and a rear end face  22  generally normal to the axis of passage  20 . The gland  28  includes a front end face  32 . The two interfaces  22  and  32  are proportioned to seat against each other. When the nut  30  is screwed onto the body (moving to the right in  FIG. 1 ), the front end face  32  of the gland  28  is pulled tight against the rear end face  22  of body  16  to form a fluid tight seal between the gland  28  and the body  16 . When the nut  30  is screwed off the body  16 , the nut is free to slide along the conduit  12  (to the left or rear in  FIG. 1 .) The nut  10  can be retracted to the left as shown in  FIG. 1  by sliding along the conduit  12  so that it&#39;s front end face  34  is to the rear of end face  22  of the body  16  as shown in  FIG. 2 , and in that condition, a conduit  12 , nut  30 , and gland  28  can slide laterally with respect to the body  16 . As a consequence of being able to retract the nut  30  until it clears the body  16 , the fitting  10  can be used in tight quarters. Axial movement of the conduit  12  is not required to separate conduit from the body  16 . 
         [0020]      FIG. 3  shows the fitting  10  in an exploded cross-section view. The body  16  includes the central passage  20 . The passage  20  carries fluid from the gland  28  to the component  14 . The body  16  also includes an external hex surface  36  which facilitates screwing the threaded end portion  18  of the body into the component  14 . In some applications the hex surface  36  may not be required, for example, where the body  16  is integrally formed with the component  14  or welded to it. 
         [0021]    The rear end portion  38  of the body  16  includes threads  40 . The threads  40  engage the threads  42  in the front end portion  44  of the nut  30 . The threads  42  and  44  cooperate to pull the nut  30  over the body  16 . The threads  42  and  44  may be replaced by any equivalent structure such as a pin and cam arrangement like those found in bayonet fittings. 
         [0022]    The body  16  terminates at a rear end face  22 . The rear end face  22  is generally flat and transverse to the axis of passage  20 . Generally, the rear end face  22  may be normal to the axis of passage  22 . An annular recess  52  is formed in the end face  22  to hold a resilient O-ring seal  54  which helps seal the gland  28  to the body  16 . 
         [0023]    The gland  28  has a forward end face  32  and a central passage  62 . The forward end face  32  is generally flat and transverse to the axis of passage  62 . Generally, the forward end face  32  may be normal to the axis of the passage  62 . When the fitting  10  is made up by turning the nut  30  onto the body  16 , the forward end face  32  of the gland  28  presses against the rear end face  22  of the body  16  and compresses the O-ring  54  to make a fluid tight seal between the gland and the body. 
         [0024]    There are numerous types of face-to-face connections which may be used. The connection between the gland  28  in the body  16  may be of the type described in SAE 1453, but many others are known and may be required for particular applications. In some the forward end face  32  of the gland  28  and the rear end face  22  of the body  16  may be provided with interlocking ridges and grooves rather than being completely flat. These ridges and grooves may be circumferential to provide a seal, or radial to provide for a particular angular alignment. In addition, as noted above, the rear end face  22  of the body  16  and the forward end face  32  of the gland  28  may be inclined with respect to the axis of the central passage  62  through the gland  28  and the central passage  20  through the body  16 . 
         [0025]    An annular face  64  in passage  62  enlarges the diameter of the passage  62  so that it can accommodate an end portion  66  of the conduit  12 . The annular face  64  limits forward movement of the conduit  12  as it is inserted into the gland  28 . 
         [0026]    The fitting  10  may use two collets, front collet  70  and rear collet  72 , to seal against the conduit  12  and to hold the conduit in place. The front collet  70  includes a cylindrical inside surface  74  that initially slides over the outside of the conduit  12 , as shown in  FIG. 4 . The front collet  70  also includes an exterior tapered surface  78 . 
         [0027]    The gland  28  ( FIG. 3 ) includes a tapered surface  80  which cooperates with the tapered surface  78  of the front collet  70 . The tapered surface  80  is conical, opening outward as it extends rearward. When the front collet  70  is forced forward, it burnishes and then squeezes the conduit  12  forming a fluid tight seal as it is driven to the position shown in  FIGS. 2 and 5 . 
         [0028]    The rear collet  72  ( FIG. 3 ) includes a tapered front end portion  82 , an annular shoulder  84 , and a cylindrical inside surface  86 . The inside surface  86  is proportioned to slide over the end portion  66  of the conduit  12  before the fitting  10  is made up for the first time, as shown in  FIG. 4 . During initial makeup of the fitting, the tapered front portion  82  of the rear collet  72  engages with a tapered entry passage  88  of the front collet  70  and is driven radially inward and bites into the conduit  12 , preventing the conduit from being withdrawn.  FIGS. 2 and 5  show the fitting  10  after it has been made up the first time. 
         [0029]    The rear collet  72  may also include a tubular extension  90  which extends rearward from the annular shoulder  84 . See  FIG. 3 . A tubular extension  90  has an outside diameter proportioned to fit through an opening  92  in the nut  30 . The tubular extension  90  serves to keep the rear collet centered and also to protect the conduit  12  from abrasion as the nut  30  is rotated. 
         [0030]    While the fitting  10  is described as using a front and rear collets  70  and  72 , it is possible to use a single collet  120  in place of the front and rear collets, and single collet flare-less fittings are well known. Such a fitting  10 ′ is shown in  FIG. 6 . Other style collets may also be used, such as the collets  122  and  124  used in fitting  10 ″ shown in  FIG. 7 . The fittings  10 ′ and  10 ″ are identical to the fitting  10  except for the collets used in changes to the nut to accommodate the collets. They need not be described further. 
         [0031]    As shown in  FIG. 3 , the nut  30  includes a central passage  94  forward of and larger than the rear opening  92 . The rear opening  92  and the central passage  94  are connected by an inclined surface  96  which is parallel to the annular shoulder  84  of the rear collet and proportioned to engage the annular shoulder of the rear collet as the nut  30  is driven forward. The central passage  94  forms a cavity in which the front and rear collets  70  and  72  are located when the fitting  10  is assembled. The forward portion of the central passage  94  includes threads  42  which, as discussed above, cooperate with the threads  40  on the body  16 . 
         [0032]    Before assembly, the gland  28 , nut  32 , and front and rear collets  70  and  72  are free of each other. Loose collets and a gland may be hard to manipulate and install correctly. Therefore the gland  28  and nut  30  are designed to retain the collets  70  and  72  prior to initial makeup of the fitting  10 . To this end, the central passage  94  in the nut  30  includes an annular ridge  100 . The annular ridge  100  includes the tapered surface  102  which faces the front of the nut  30  and a stop surface  104  which faces to the rear. The annular ridge  100  in the nut  30  cooperates with a similar annular ridge  106  located at the rear end of the gland  28 . The ridge  106  in the gland  28  includes a tapered surface  108  which faces rearward and a stop surface  110  which is more nearly perpendicular to the axis of the gland  28  and faces forward. The ridges  100  and  106  act as a one-way catch, allowing assembly but not disassembly of the nut  30  onto the gland  28 . 
         [0033]    To assemble the nut  30 , collets  70  and  72 , and gland  28 , the front collet  70  is first placed in the gland  28  with the tapered surface  78  of the front collet  70  touching the tapered surface  80  of the gland. Next, the rear collet  72  is positioned with its forward tapered surface  82  in contact with the tapered surface  88  at the rear of the front collet  70 . Thereafter the nut  30  is placed over the two collets  70 ,  72  and the gland  28 . As the ridge  106  at the rear of the gland passes the rear end of the threads  42 , the tapered surface  108  of the ridge  106  engages the tapered surface  102  of the ridge  100 . A slight force is required to squeeze the ridge  106  past the ridge, facilitated by the two tapered surfaces  108  and  102  and the relatively thin section  112  at the rear of the gland  28 . As the gland is forced further into the central passage  94  in the nut  30 , the ridge  106  expands radially outward, and thereafter the stop surface  110  and the stop surface  104  on the gland  28  and nut  30 , respectively, prevent the gland  28  from being removed. Thus the collets  70  and  72  and the gland  28  are captured within the nut  30 , and it is therefore impossible to lose the two collets  70  and  72  without destructively removing the gland  28 . The position of the ridge  106  and the ridge  102  are selected so that the stop surfaces  104  and  110  engage each other as the nut is being moved rearward only after the end face  34  of the nut  30  has moved rearward of the end face  60  of the gland  28 , as shown in  FIG. 2 . 
         [0034]    As an alternative to the ridges  100  and  106 , a threaded arrangement may be used as shown in  FIG. 8 . Here the female threads  42 ′ in the nut  30 ′ extended rearward to join the passage  94 . (The ridge  100  in the nut has been eliminated.) On the gland  28 ′, the ridge  106  has been replaced by male threads  140 . The threads at  140  cooperate with the threads  42 ′. Because the male threads  140  have an outside diameter smaller than the inside diameter of the passage  94  through the nut  30 , once the nut  30  has been screwed onto the gland  28 ′ by turning it through the required number of turns, the gland is free to move axially within the nut, and the collets  70  and  72  are captured within. 
         [0035]    Another alternative to the ridges  100  and  106  is to replace one of them with a spring clip  150 .  FIG. 9 . For example, the ridge  106  may be replaced with a annular recess  152  proportioned to receive the spring clip  150 . When the ridge  100  is pressed past the spring clip  150 , it cannot be removed, thus guaranteeing that the collets will be retained in place between the nut  30  and gland  28  prior to initial make up of the fitting  10 . In a further variation, the ramp  100  and/or the ramp  106  may shaped to retain the gland but allow disassembly. This can be done, for example, by making the stop face  104  a ramp, symmetrical with the tapered surface  102 . 
         [0036]    Various techniques may be used to assure that the collets  70  and  72  remain properly aligned prior to insertion of the conduit  12  into the fitting  10  and initial makeup of the fitting on the conduit. One such arrangement is shown in  FIG. 4 . Here the body  16  has been threaded into the nut  30  until there is contact between the tapered surface  80  of the gland  28 , the tapered surface  78  of the front collet  70 , between the tapered surface  88  at the rear of the front collet and the tapered surface  82  at the front of the rear collet  72 , and between the shoulder  89  on the rear collet and the tapered surface  96  in the nut. The contact should not involve an axial preload which might distort the collets making installation of the conduit  12  difficult. 
         [0037]    Other techniques may also be used to hold the collets  70  and  72  in alignment with the passage  92  through the nut  30  and the passage  62  through the gland  28 . These techniques include adhesives and/or lubricants to hold the collets  70  and  72  and gland  28  in proper orientation. One product that may be used is wax which may hold the collets  70  and  72  in place. The adhesive and/or lubricant may be applied as a coating or it may be foamed to full the entire space between the collets  70  and  72  and the nut  30  except for a passage where the tube  12  will be inserted. As an alternative, the tubular extension  90  of the rear collet  72  may be extended so that even when the gland  28  is in its forward most position, the tubular extension is housed within the rear opening  92  in the nut  30 . In this case the tubular extension may be provided with a dimple which projects outwardly and contacts the passage  92  through the nut  30 . Upon initial makeup of the fitting, the dimple is forced through the passage  92  in the nut, its purpose having been served. 
         [0038]    To use the fitting  10 , a conduit  12  is inserted through the opening  92  in the nut  30 , through the passage  86  through the rear collet  72 , through the passage  74  through the front collet  70 , and into the gland  28  until the leading end face of the conduit  12  contacts the annular face  64  in the gland. See  FIG. 4 . The gland  28  is then placed with its front end face against the rear end face  22  of the body  16 . The nut  30  is then turned to engage the threads  40 ,  42  to pull the nut forward. The inclined surface  96  in the nut forms a shoulder which engages the annular shoulder  84  of the rear collet  72 , pushing it forward. The rear collet  72  in turn pushes the front collet  70  forward into the tapered surface  80  at the rear of the gland  28 . As the nut  30  moves forward, the collets  70  and  72  slide along and then are compressed around and into the conduit  12 , sealing against it. At the same time the front face  32  of the gland  28  is pressed against the rear face  22  of the body  16 , compressing the O-ring  54  and effecting a seal between the gland and the body, as shown in  FIG. 5 . Thus a single nut  30  serves both to drive the collets  70  and  72  into sealing engagement with the conduit  12  and to pull the front face  32  against the rear face  22  of the body  16 . It is noteworthy that a single operation, holding the body  16  against rotation while turning the nut  30 , serves both to compress the collets  70  and  72  onto the conduit  12  and to seal the gland  28  against the body  16 . In addition, the fitting  10  is axially compact, allowing it to be used in some applications where longer fittings or combinations of fittings cannot be used. 
         [0039]    When it is necessary to disconnect the conduit  12  from the component  14 , the nut  30  may be screwed back and then slid rearward until its end face  34  is rearward of the front face  32  of the gland  28 , as shown in  FIG. 2 . This allows lateral movement of the gland  28  and nut  30  with respect to the body  16  with little or no axial movement of the forward end face  32  of the gland away from the rear end face  22  of body  16 . 
         [0040]    While the inventive principles have been illustrated by the description of various embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will be readily apparent to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus, methods and examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive principles.