Abstract:
A tube coupling includes a coupling body ( 10 ) having an open ended throughway ( 11 ) to receive a tube ( 16 ). A collet ( 20 ) is located in the open end of the throughway having a ring ( 21 ) and a plurality of flexible arms ( 22 ) extending into the throughway. The throughway has a tapered cam surface ( 25 ) convergent towards the open end and the collet arms have heads ( 23 ) at their distal ends for engaging both the cam surface and a tube extending through the collet into the throughway to be compressed against the tube by the cam surface with outward movement of the collet with respect to the throughway to secure the tube in the throughway. A collet lock ( 27 ) is rotatably mounted on the coupling body having one rotary position in which the lock holds the collet ( 20 ) and another rotary position in which the collet can move axially.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to United Kingdom Application Serial Nos. 0809685.1, filed May 28, 2008 and 0811665.9, filed Jun. 25, 2008, which are incorporated herein by specific reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. The Field of the Invention 
         [0003]    This invention relates to tube couplings for providing tube connections in lines of tube or pipe for conducting fluids in the form of gases or liquids. 
         [0004]    2. The Relevant Technology 
         [0005]    In our UK Patent Specification No. 1520742 we describe and illustrate a tube coupling comprising a coupling body having an open ended throughway to receive a tube. A collet is located in the open end of the throughway having a ring and a plurality of flexible arms extend generally of the ring into the throughway. 
         [0006]    The throughway has a tapered cam surface convergent towards said open end of the throughway and the collet arms having heads at their distal ends for engaging both the cam surface and a tube extending through the collet into the throughway. The head on the collet arms are compressed against the tube by the cam surface with movement of the collet towards the open end of the throughway to secure the tube in the throughway. The collet ring extends out of the throughway and has an out-turned flange or head to facilitate manipulation of the collet by a tool or by hand to lock and release a tube in the coupling body. A “C” shaped locking clip may be provided for engagement between the head or flange of the collet and the adjacent end of the coupling body to hold the collet in an outwardly extended position in which the tube is locked in the coupling body by the collet to prevent accidental release of the collet. The provision of a separate component for the locking function can result in a collet being left unlocked if a clip is not available for a coupling body or the installer simply overlooks applying the clip to the collet. 
       SUMMARY OF THE INVENTION 
       [0007]    This invention provides a tube coupling comprising a coupling body having an open ended throughway to receive a tube, a collet located in the open end of the throughway having a ring and a plurality of flexible arms extending generally axially of the ring into the throughway, the throughway having a tapered cam surface convergent towards said open end and the collet arms having heads at their distal ends for engaging both the cam surface and a tube extending through the collet into the throughway to be compressed against the tube by the cam surface with outward movement of the collet with respect to the throughway to secure the tube in the throughway and a collet lock rotatably mounted on the coupling body having one rotary position in which the lock holds the collet in said outward tube securing position and another rotary position in which the collet can move axially with respect to the throughway for release and engagement of a tube by the collet. 
         [0008]    In a preferred arrangement according to the invention the collet lock has means for driving the collet outwardly of the throughway with rotation of the lock and to retain the collet in an outward tube securing position. 
         [0009]    More specifically the collet lock and coupling body may have interengaging guide means to displace the collet lock axially outwardly of the coupling body with rotation of the collet lock and thereby to drive the collet outwardly of the coupling body. 
         [0010]    For example, the interengaging means acting between the collet lock and the coupling body may comprise cam means acting between the collet lock and coupling body. 
         [0011]    In the latter arrangement the cam means may comprise a cam and cam follower on the collet lock and coupling body respectively or vice versa. 
         [0012]    In any of the above arrangements the collet lock may comprise a sleeve encircling the coupling body. 
         [0013]    In the latter case the sleeve may be coupled to the ring of the collet to draw the collet outwardly of the coupling body with axial movement of the sleeve outwardly of the coupling body. 
         [0014]    In one, preformed arrangement the collet ring projects from the open end of the coupling body and one end of the sleeve projects beyond that end of the coupling body and has an in-turned flange which engages with the ring so that axially outward movement of the cap drives the collet axially outwardly of the throughway. 
         [0015]    More specifically the collet ring may have an out-turned head and the flange of the sleeve may engage behind the head. 
         [0016]    In any of the latter arrangements said cam surface may be formed around the coupling body and a cam or cams may be formed in the sleeve which engage the cam surface. 
         [0017]    In one example according to the invention the cam surface may be formed on the outer side of the coupling body within the sleeve and the cam or cams may be formed in the sleeve. 
         [0018]    In a further arrangement, the cam surface may be formed on the throughway within the coupling body and the cam or cams may be formed on the in-turned flange at said one end of the sleeve and to engage the cam surface and project into the throughway. 
         [0019]    In any of the latter arrangements the cam surface on the coupling body may be shaped so that there is 90° of rotation of the cap between the collect locked and collet released positions. 
         [0020]    According to a further feature, the cam surface is shaped to resist rotation of the sleeve in either direction from the collet locking position. 
         [0021]    For example, the cam surface may be provided with a shallow recess to receive the cam in the collet locking position to provide resistance to rotation of the sleeve from the collet locking position in either direction. 
         [0022]    In any of the above arrangements the coupling body may have one or more apertures to enable the location of a tube inserted into the throughway to be viewed. 
         [0023]    In the latter case the sleeve is shaped to cover the aperture or apertures in the collet locked position and to reveal the aperture or apertures in the collet released position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The following is a description of some specific embodiments of the invention, reference being made to the accompanying drawings in which: 
           [0025]      FIG. 1  is a cross-sectional view through a tube coupling having a coupling body, a collet in the coupling body for locking a tube in place, a tube inserted into the coupling body and a locking device for the collet to prevent inadvertent release of a tube from the coupling body with the locking device shown in the unlocked position and with a window in the coupling body to view the locking mechanism revealed by the collet locking device; 
           [0026]      FIG. 2  is a similar view to  FIG. 1  showing the locking device in the collet locking position and the window into the coupling body covered by the collet locking device; 
           [0027]      FIG. 3  is a view of the tube coupling in a condition shown in  FIG. 2  with the section taken at 90° to that of  FIG. 2 ; 
           [0028]      FIG. 4  is a perspective view of the tube coupling as shown in  FIG. 1  with the tube omitted; 
           [0029]      FIG. 5  is a perspective view of the tube coupling as shown in  FIG. 2  with the tube omitted; 
           [0030]      FIG. 6  is a perspective view of the tube coupling as shown in  FIG. 5  with the collet locking device omitted; 
           [0031]      FIG. 7  is a side view of the coupling body as shown in  FIG. 6 ; 
           [0032]      FIG. 8  is a perspective view of the collet locking sleeve; 
           [0033]      FIGS. 9 to 13  are perspective views of a double-ended version of the coupling body of  FIGS. 1 to 5  showing the sequence of operations in inserting a tube into one end of the coupling body, locking the tube in the coupling body against removal and releasing the lock to enable the tube to be withdrawn; 
           [0034]      FIGS. 14 to 18  are similar views to  FIGS. 5 to 8  showing a modified cam encircling the outer side of the coupling body and cam follower in the collet locking sleeve; 
           [0035]      FIGS. 19 to 32  correspond to  FIGS. 1 to 13  and show a third modified arrangement; 
           [0036]      FIGS. 33 to 41  show a fourth modified arrangement and  FIGS. 42 to 50  show a fifth modified arrangement; and 
           [0037]      FIGS. 51 and 52  show a sixth modified arrangement. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]    Referring firstly to the arrangement of  FIGS. 1 to 8  of the drawings, there is shown a tube coupling body  10  moulded in high strength plastics material having a central throughway  11  which terminates in an internal cylindrical spigot  12 . 
         [0039]    An annular recess  13  extends into the wall of the coupling body from an end face  14  of the coupling body and terminates in a step  15  to form a socket for receiving an end of a tube  16  around the spigot  12 . 
         [0040]    The external surface of the spigot adjacent the end  15  of the socket is corrugated as indicated at  17  to grip the internal surface of the tube  16  and the outer surface of the spigot is also formed with two spaced annular grooves  18  in which O ring seals  19  are located to seal with internal surface of the tube  16  located over the spigot. 
         [0041]    The tube is held on the spigot in the socket by means of a collet indicated at  20  also formed in moulded plastics. The collet comprises a ring  21  located at the mouth of the socket and having a plurality of axially extending flexible arms  22  which terminate in heads  23 . Metal teeth  24  are moulded into the heads and project on the inner sides of the heads to engage and grip the tube  16 . 
         [0042]    The wall of the coupling body around the socket is formed with a tapered cam surface  25  converging towards the open end of the socket with which the heads  23  are engageable to compress the heads against the outer surface of the tube with a slight withdrawal movement of the collet from the coupling body. 
         [0043]    The ring  21  of the collet projects outwardly of the open end of the socket and has an integral out-turned flange or head  26  which overlies the end of the coupling body. 
         [0044]    A collet lock comprising sleeve  27  is located on the coupling body adjacent the open end of the coupling body for rotation about the coupling body and also for axial sliding movement on the end of the coupling body. The sleeve has an in-turned flange  28  which engages between the end of the coupling body and the head  26  of the collet. 
         [0045]    The outer wall of the coupling body encircling the socket is formed with spaced ports  29  to enable the locking of a tube by the heads of the collet to be viewed and checked by the operator. 
         [0046]    Referring now to  FIGS. 6 to 8  of the drawings, the external wall of the coupling body adjacent the end  14  is formed with an encircling cam surface indicated at  30  and facing towards the open end of the throughway. The cam surface has two deep slots  31  extending along the coupling body from the open end of the body past the windows  29  and between the slots the cam surface comprises shallow rising ramps  32  extending from the sides of the slot which end in short ridges  33  with a shallow recess  34  between the ridges. 
         [0047]    The sleeve  27  has a pair of generally rectangular integral cam followers  35  (only one of which can be seen in  FIG. 8 ) which are moulded integrally with the inner side of the sleeve and the in-turned flange at the end of the sleeve. The cam followers  35  have a circumferential length corresponding to the width of the slots  31  formed in the cam face on the coupling body. The cam followers engage the cam face and by rotation of the sleeve the axial position of the sleeve with respect to the coupling body is adjusted. When the cam followers  35  are engaged in the slots  31 , the flange  29  on the sleeve is located against the end of the coupling body and the collet can be pushed into the socket in the coupling body until the head  26  of the collet engages the flange  28  of the sleeve. In that position of the collet, the heads on the arms of the collet are just disengaged from the tapered cam surface in the coupling body allowing the tube to be inserted or withdrawn from the coupling body. When the sleeve  27  is rotated through 90° to disengage the cam followers  35  from the slots  31 , the cam followers ride up the ramps  32  lifting the in-turned end  28  of the sleeve away from the end of the coupling body and forcing the head  26  of the collet away from the end of the coupling body. The cam followers  35  eventually ride over the ridges  33  at the top of the ramps and then drop into the recesses  34  which hold the cam followers against rotation with respect to the coupling body. In this position the heads  23  of the collet are held forcibly against the tapered cam surface  25  in the coupling body locking the heads against the tube  16  and thereby locking the tube in the coupling body. To release the tube from the coupling body, the sleeve  27  is rotated to drive the cam followers  35  out of the recesses  34  and then back into register with the slots  31  where a sleeve can again slide axially over the coupling body until the flange of the sleeve engages the end of the coupling body allowing the collet  20  to move inwardly to release the gripping engagement of the heads of the collet with the tube. 
         [0048]    In a further arrangement which is not illustrated the cam is formed in the cap and the cam followers on the coupling body to displace the cap axially with rotation of the cap as outlined above. 
         [0049]    The end  40  of the sleeve remote from the top wall  28  is formed with alternate troughs and peaks around the sleeve such as a sinusoidal shape so that in the troughs of the shape, the windows  29  in the coupling body wall are revealed to enable the locking of the tube in the coupling body to be viewed. The windows  29  are exposed when the sleeve is in the collet release position so that the operator can see that the tube  16  is fully inserted onto the spigot  12  in the coupling body before rotating the sleeve to cause the product to grip and lock the tube in position. In the latter position of the sleeve with the cam followers  35  engaged in the recesses  34  in the cam face, the peaks of the sleeve cover the slots in the coupling body. It will be appreciated that other shapes may be applied to the end of the sleeve to achieve the same effect. For example the end of the sleeve may have spaced indentations or recesses to reveal the windows in the coupling body. 
         [0050]      FIGS. 9 to 13  show a double-ended coupling body of the form shown in  FIGS. 1 to 8  showing a sequence in which the tube is inserted into the coupling body, the sleeve is rotated to lock the tube in the coupling body, the sleeve is rotated to release the tube and the collet is pressed inwardly to allow the tube to be withdrawn from the coupling body. 
         [0051]      FIGS. 14 to 22  show a similar arrangement with modified cam profile  31  and cam follower  35  as best seen in  FIGS. 16 to 18 . The extent of axial displacement of the sleeve is reduced in this arrangement because the cam has only shallow recesses  31  extending along the coupling body in place of the deep slots  31  of the previous arrangement. The features of the arrangement are otherwise similar to the previously described embodiments. 
         [0052]      FIGS. 9 to 27  show a still further arrangement in which the cam surface  31  for actuating the sleeve is formed internally in the mouth of the coupling body and the cam followers  35 . 
         [0053]      FIGS. 33 to 41  and  42  to  50  show still further forms of cam around the mouth of the coupling body and on the in-turned flange at the end of the sleeve. Again the operation of the sleeve for locking and releasing the collet is much the same as that described in respect of the first embodiment. 
         [0054]    In a further arrangement applicable to any of the above arrangements rotation of the sleeve with respect to the coupling body is limited to 180° by, for example, an element on the sleeve and an end stop formed in said cam. 
         [0055]      FIGS. 51 and 52  show yet a further application of the invention.  FIG. 51  shows the coupling body  10  of the modified arrangement with the collet and collet lock removed. 
         [0056]    The coupling body end  14  has a peripheral rebate indicated generally at  50  which forms an axially facing step  51  adjacent the end of the coupling body and a short collar  52  on the end of the coupling body. The collar  52  has four equi-spaced integral, outwardly projecting lugs  53  the outer faces of which are slightly proud of the outer face of the coupling body  10 . 
         [0057]    Each lug  53  has an adjacent cam  54  which winds around the collar  52 . Each cam comprises a ramp  55  rising from the step  51  to a flat  56  extending parallel to the end of the coupling body and which leads to the lug  53  associated with the cam. A short spline  57  is formed down the outer side of the collar  52  above the flat  56  adjacent one side of the lug  53  and a similar spline  58  is formed on the outer side of the collar adjacent the other side of the lug  53 . 
         [0058]    Referring now to  FIG. 52  of the drawings, the sleeve  27  has four equi-spaced cam followers  35  moulded in the sleeve adjacent the end flange  28  of the sleeve. Each cam follower  35  has splines  59  formed on the inner side of the cam follower at either end thereof for a purpose to be described later. Tapered slots  60  extend axially along the inner side of the sleeve to one side of each of the cam followers  35 . 
         [0059]    When the sleeve  27  is assembled on the coupling body, the slots  60  are aligned with the lugs  53  to ease the location of the sleeve onto the coupling body. The cam followers  35  engage in the peripheral rebate  50  around the end of the coupling body, each follower being movable between a lug  53  and a cam  54 . When the sleeve  27  is rotated to cause the cam followers  35  to rise up the ramps  55 , the sleeve is displaced axially outwardly of the coupling body as described earlier to hold the collet located in the mouth of the coupling body in the tube locking position. The sleeve reaches its position of maximum axially outward movement from the coupling body when the cam followers  35  move onto the flats  56  of the cams. The sleeves  35  can be locked in that position by forcing the leading spline  59  of the cam follower  35  past the spline  57  on the adjacent side of the lug  53  to resist return movement of the sleeve. 
         [0060]    When the sleeve is rotated in the opposite direction, the cam followers  35  run over the flats  56  and down the ramps  55  of the cams  54  onto the step  51 . The sleeve is then allowed to move axially over the coupling body releasing the locking engagement of the collet with the tube and allowing the tube to be withdrawn from the coupling body. The sleeve can be retained in that position by snapping the spline  59  at the leading end of the cam follower in its return movement past the spline  58  on the side of the lug  53  adjacent the bottom of the ramp  55 . Thus the cam followers  35  are constrained to move between adjacent pairs of lugs  53  to have an overall rotation of a little less than 90°. 
         [0061]    The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.