Abstract:
The present invention is concerned with a connector and in particular a connector capable of connecting both male to male and female to female parts. The present invention thus provides a connector part ( 30 ) including a body-portion ( 31 ) and at least one arm ( 40 ) that projects from an end of the body-portion ( 31 ), the or each arm ( 40 ) being arranged such that the connector part ( 30 ) can be mated with another, substantially identical connector part ( 39 ), so that the or each arm of the connector part ( 30 ) interposes the or each arm of the respective other connector part ( 30 ), wherein the first-connector part ( 30 ) has engagement means ( 33, 42 ) operable to be releasably engaged by the or each arm ( 40 ) of the substantially identical connector part, thereby fixing it relative to the first-said connector part.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is an U.S. national phase application under 35 U.S.C. §371 based upon co-pending International Application No. PCT/GB2006/000152 filed on Jan. 17, 2006. Additionally, this U.S. national phase application claims the benefit of priority of co-pending International Application No. PCT/GB2006/000152 filed on Jan. 17, 2006 and Great Britain Application No. 0500943.6 filed on Jan. 17, 2005. The entire disclosures of the prior applications are incorporated herein by reference. The international application was published on Jul. 20, 2006 under Publication No. WO 2006/075188 A1. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to connector parts and in particular to connector parts for connecting one tubular component to another.  
         [0004]     2. Description of the Prior Art  
         [0005]     Conventional connection apparatus often includes two mating parts: a male part and a female part. The two parts are usually arranged such that the male part is insertable into the female part and releasably fixable thereto. An example of such connection apparatus is a garden hose, where lengths of hose pipe are usually connectable to one another by the provision of either such a male or female part at each end of the hose lengths. However, connection apparatus such as this is disadvantageous in that a male part may not be connected to another male part; and a female part may not be connected to another female part.  
       SUMMARY OF THE INVENTION  
       [0006]     It is an object of this invention to address this problem.  
         [0007]     According to an aspect of this invention there is provided a connector part including a body portion and at least one arm that projects from an end of the body portion, the or each arm being arranged such that the connector part can be mated with another, substantially identical connector part, so that the or each arm of each connector part interposes the or each arm of the respective other connector part, wherein the first-said connector part has engagement means operable to be releasably engaged by the or each arm of the substantially identical connector part, thereby fixing it relative to the first-said connector part.  
         [0008]     Preferably the engagement means are operable by pushing the two connector parts together.  
         [0009]     “Substantially identical” is used to refer, for example, to connector parts produced by the same manufacturing process, e.g. produced using the same mould or the same electronically stored instructions for operating a manufacturing machine, and therefore does not exclude connector parts with variations due to manufacturing tolerances or other such unintended variations. This is advantageous in that only one type of connector part need be manufactured, rather than separate male and female type connector parts, thereby reducing the complexity and cost of the manufacturing process. Thus, it will be appreciated that, unless clearly stated to the contrary, features described as being included in the first-said connector part are also included in the substantially identical, mating connector part and vice versa. The engagement means may include catch means by which one or more arms of the mating connector part are fixable relative to the first-said connector part. The engagement means may include at least part of a lip-and-catch arrangement, one of the lip and the catch being provided on the first-said connector part and the other of the lip and the catch being provided on one or more arms of the mating connector part. Preferably, one or more arms of the first-said connector part includes a catch surface and the body portion includes a lip, the catch surface being arranged to be pushed over the lip of the mating connector part into a position in which the catch surface abuts the lip of the mating connector part when the two connector parts are pushed together, such that separation of the two connector parts is resisted by that abutment. The arm or arms may therefore be considered to “latch over” the lip. Preferably the lip is provided around the body portion. Preferably a respective catch surface is provided adjacent a leading edge of each arm or arms.  
         [0010]     The body portion may be substantially tubular and may be hollow. Preferably, the body portion is substantially cylindrical. The or each arm is preferably arcuate in cross section and projects from a radially outer surface of the end of the body portion, the inner radius of the or each arm being substantially the same as the outer radius of the body portion such that the or each arm is a sliding fit on the body portion of the mating connector part. The body portion may have a mating surface at the end thereof, the mating surface being substantially midway between the lip and the catch surface of the connector part, such that when that connector part is mated with the other, substantially identical connector part, the two mating surfaces abut one another so as to provide a sealed connection between the two connector parts. The mating surface is preferably a flat annular surface, perpendicular to the axis of the tubular body portion. The mating surface may include a seal, such as an o-ring partially embedded therein. Preferably, the seal is an o-ring wherein said o-ring seal is modified to form a toroidal ring having a generally circular cross section with an integral lip which is angled towards the ring axis and which forms the mating face of the seal. When in an assembled condition the two mating surfaces abut one another such that opposing modified o-rings are compressed to form a seal able to withstand internal pressure by virtue of the opposing integral lip shaped protrusions.  
         [0011]     The or each arm may be waisted adjacent the leading edge thereof such that the leading edge is deflectable relative to the remainder of the respective arm thereby facilitating the latching of each catch surface over the respective lip.  
         [0012]     Preferably the first-said connector part includes at least two arms. The arms of the first connecting part or of the mating connector may have one or more longitudinal slits provided which improve the flexibility of the arm and aid the formation of the catch-lip engagement.  
         [0013]     The first-said connector part may be a single, integral piece. The first-said connector part may include two or more pieces. The first-said connector part preferably includes a tubular, radially innermost piece inside a sleeve, the radially innermost piece including the mating surface and the sleeve including the body portion and the arms. Preferably the radially innermost piece is axially abuttable by the sleeve such that when mated to the mating connector part, the two radially innermost pieces are pressed together at their mating surfaces to create a sealed connection therebetween.  
         [0014]     The first-said connector part may include additional engagement means operable to resist the retraction of at least one of the arms of the mating connector part from the first-said connector part by resisting the un-latching of one or more catch surface of the mating connector part from the lip of the first-said connector part. Preferably, the additional engagement means includes a ring operable to surround and radially constrain the radially outermost surfaces of the arms of the mating connector part, thereby preventing the or each catch surface thereof from riding back over the lip. The ring may be releasably locatable in a position in which it radially constrains the arms by the provision of a lip-and-catch arrangement between the ring and the arms. Preferably the ring includes an inwardly-projecting lip adjacent a leading edge of the ring and preferably at least one arm includes a second, cooperating catch surface on its radially outermost surface. Preferably the second catch surface is provided adjacent a mid point of the arm, such that resilience of material of the arm causes the arm to abut both the ring that surrounds it and the body portion with which it is engaged.  
         [0015]     In an alternative embodiment, the engagement means may comprise at least one lock ring and an abutment on said at least one arm of the first connector part or mating connector part, said lock ring having a formation which is operable to engage and axially constrain said at least one arm by rotation of said lock ring around its longitudinal axis relative to the first connector part or mating connector part. Preferably the formation on said lock ring includes a helical surface and said abutment on said arm or arms includes a helical surface, said helical surfaces being frictionally engageable during rotation of said lock ring about its longitudinal axis relative to the first connector part or mating connector part so that relative rotation of the lock ring and arms is resisted. Preferably, the lock-ring comprises one or more cutaway sections adjacent the leading edge of the ring which allow the lock-ring to pass over the abutments on the arms of the first connecting part or mating connector.  
         [0016]     Preferably the first connecting part may be mated to the mating connector part with both the catch and lip engagement means and the twisting engagement means described above to create a seal connection therebetween. Alternatively, the catch and lip and twisting engagement means may be used independent of one another.  
         [0017]     A tertiary lock may be incorporated in the engagement means to provide a more secure seal between the first connecting part and the mating connector part. The tertiary lock may be provided by a further lip and catch arrangement, one of the lip and catch being provided at the end of one or more of the arms of the first connecting part or mating connector and the other of the lip and catch being provided in a corresponding position on the radially internal surface of the locking ring.  
         [0018]     Although it is stated above that the first-said connector part is preferably for connecting to another connector part substantially identical to the first-said connector part, the first-said connector part may be for connecting to a further connector part having substantially the same arm arrangement and substantially the same body portion such that the two connector parts can be mated, but the further connector part including further features or structure. For example, a body portion of the further connector part may be integral with tubing used for conveying liquids or gases such as a hose pipe nozzle or a sprinkler head, or, for example, the further connector part may have a body portion that is formed into a right angle.  
         [0019]     According to another aspect of this invention there are provided two connector parts, each connector part being substantially identical to the respective other connector part, and each connector part including a body portion and at least one arm that projects from an end of the body portion, the or each arm of each connector part being arranged such that each connector part can be mated with the respective other connector part so that the or each arm of each connector part inter-digitates with the or each arm of the respective other connector part, wherein each connector part has engagement means operable to be releasably engaged by the or each arm of the respective other connector part, thereby fixing the two connector parts together.  
         [0020]     Optional features of the first-said connector of the one aspect of this invention may also be optional features of each of the connector-parts of the other aspect of this invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     Specific embodiments of this invention are now described by way of example only and with reference to the accompanying drawings, in which:  
         [0022]      FIG. 1  is a sectional view of two mated connector parts employing a push engagement means;  
         [0023]      FIG. 2  is a plan view and a part-sectional view of a radially innermost piece of one of the connector parts;  
         [0024]      FIG. 2   a  is an end view of the radially innermost piece;  
         [0025]      FIG. 2   b  is a detailed sectional view of part of the radially innermost piece;  
         [0026]      FIG. 3  is a sectional view of a sleeve of the connector part;  
         [0027]      FIG. 3    a  is a plan view of the sleeve;  
         [0028]      FIG. 3   b  is an end view of the sleeve;  
         [0029]      FIG. 4  is a sectional view of a lock ring of the connector part.  
         [0030]      FIG. 5  is a sectional view of two mated connector parts employing a twisting engagement means.  
         [0031]      FIG. 5   a  is an enlarged sectional view of opposing o-lip seals at abutting mating surfaces.  
         [0032]      FIG. 6  is a detailed sectional view of the body portion of the connector part.  
         [0033]      FIG. 6   a  is a plan view of an arm of a connector part showing a helical radially outermost surface.  
         [0034]      FIG. 6   b  is an enlarged sectional view of a groove provided at the mating surface.  
         [0035]      FIG. 6   c  is an end view of an arm of a connector part.  
         [0036]      FIG. 7  is a sectional view of a lock ring with helical radially innermost surface.  
         [0037]      FIG. 7   a  is a scrap view in the direction of arrow A in  FIG. 7  showing the helical radially innermost surface.  
         [0038]      FIG. 7   b  is an end view of the lock ring.  
         [0039]      FIG. 8  is a cross section of a toroidal shaped o-lip seal.  
         [0040]      FIG. 8   a  is an enlarged sectional view of a toroidal shaped o-lip seal.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0041]      FIG. 1  shows two generally cylindrical connector parts  10 ,  10 ′. The connector parts  10 ,  10 ′ are shown in cross section, the section being taken along a longitudinal axis of the connector parts  10 ,  10 ′. The two connector parts  10 ,  10 ′ are substantially identical and so the structure of one  10  of the connector parts  10 ,  10 ′ only will be described for simplicity, it being understood that the structure of the other connector part  10 ′ is the same, within the limits of normal and acceptable manufacturing variation.  
         [0042]     The connector part  10  includes a radially innermost piece  20 , a sleeve  30  and a lock ring  50 .  
         [0043]     The radially innermost piece  20  is substantially cylindrical and is formed of a single piece of injection-moulded plastic, for example an acetal homopolymer plastic, such as DELRIN. Such plastics exhibit good resistance to fatigue and tend not to absorb water. As is shown more clearly in  FIG. 2 , the radially innermost piece  20  has a non-mating end  22  and a mating end  24 . The internal diameter of the cylindrical radially innermost piece  20  is constant along the length of the radially innermost piece  20 , however a screw thread  26  is formed in the inner surface of the radially innermost piece  20  at its non-mating end  22 . The screw thread  26  is for connecting the non-mating end  22  of the radially innermost piece  20  to apparatus (not shown) that is to be connected to other apparatus (not shown) by means of the two connector parts  10 , 10 ′. For example, an end of a length of garden hose (not shown) may include a cooperating screw thread on the outside thereof that can be screwed into the non-mating end  22  of the radially innermost piece  20 . Alternatively, an end of a mechanical transmission shaft (not shown) may be screwed into the non-mating end  22  of the radially innermost piece  20 .  
         [0044]     As shown in  FIG. 2 , the outside surface of the radially innermost piece  20  is stepped so as to be of lesser diameter at the non-mating end  22  than at the mating end  24  thereof, with a step  120  therebetween. To facilitate screwing such apparatus as that mentioned above to the non-mating end  22  of the radially innermost piece  20 , the outer surface of the radially innermost piece  20  includes two parallel and radially opposite flat surfaces  21  adjacent the non-mating end. These flat surfaces  21  are shown in  FIG. 2A  and are arranged for gripping by an operator or placing between the jaws of a wrench, so as to gain angular purchase on the radially innermost piece  20 .  
         [0045]     With reference to  FIG. 2 , the mating end  24  of the radially innermost piece  20  includes a mating surface  27 . The mating surface  27  is a flat, annular surface that lies in a radial plane of the radially innermost piece  20 . A continuous annular channel  28  is formed in the mating surface  27  so as to have an opening that projects axially. The channel  28  houses a resiliently compressible o-ring seal  29  that, in an uncompressed condition, projects slightly beyond the opening of the channel  28 . A radially innermost wall  28 A of the channel  28  is oblique to the axis of the radially innermost piece  20  such that the channel  28  is narrower towards its opening. This serves to retain the seal  29  in the channel  28 .  
         [0046]      FIG. 3  shows the sleeve  30  in more detail. The sleeve  30  is also a single piece of injection-moulded DELRIN. The sleeve  30  includes a cylindrical portion  31  with two arms  40  projecting from a mating end  34  of the cylindrical portion  31 . The cylindrical portion  31  of the sleeve  30  is for fitting closely around the outside of the radially innermost piece  20 . Thus, the inside surface of the cylindrical portion  31  is stepped so as to be of lesser diameter at a non-mating end  32  thereof than at a mating end  34  thereof, with a step  130  therebetween. When the sleeve  30  is fitted around the outside of the radially innermost piece  20 , the mating surface  27  of the radially innermost piece  20  projects beyond the mating end  34  of the sleeve  30 .  
         [0047]     The cylindrical portion  31  of the sleeve  30  has an outside that is of constant diameter, save for the provision of a ridge-like lip  33  and a circlip groove  39 . These are shown in  FIG. 3A . The lip  33  runs circumferentially around the outside of the cylindrical portion  31  and is v-shaped in cross-section. The lip  33  is positioned substantially midway along the length of the cylindrical portion  31 , but at a specified axial distance from the step  130  of the inside surface of the cylindrical portion  31 . The circlip groove  39  runs circumferentially around the outside of the cylindrical portion  31 , adjacent the non-mating end  32  thereof.  
         [0048]     Each arm  40  includes a base portion  45  and a tip portion  46 . Each base portion  45  projects from the cylindrical portion  31  of the sleeve  30 , and each tip portion  46  projects from the respective base portion  45  to a respective tip  47 . The two arms  40  are diametrically opposed, project axially and are arcuate in cross section so as to be concentric with the cylindrical portion  31 . The arcuate width of the tip portion  46  of each arm  40  tapers towards a shorter arcuate width at the tip  47  of that arm  40 . This reduction in the arcuate width of each tip portion  46  is intended to promote bending and ease of engagement of the tip portion  46  for reasons that are described below.  
         [0049]     With reference to  FIG. 3 , the outside surface of the base portion  45  of each arm  40  is of constant radius. The outside surface of each base portion  45  is joined to the outside surface of the respective tip portion  46  by a chamfer  48  such that the radius increases from the base portion  45  to the tip portion  46 . The outside surface of each tip portion  46  tapers from the respective chamfer  48  to a smaller radius at the respective tip  47 . Thus, each chamfer  48  and the respective tip portion  46  meet at a respective ridge  49 .  
         [0050]     The inside radius of each of the arms  40  is such that they would be a sliding fit over the lip  33 . At the tip portion  46  of each arm  40 , structure thereof projects radially inwards so as to form a respective, inwardly-projecting, arcuate, shallow flange  42 . The radius of each shallow flange  42  is such that the shallow flanges  42  would be a sliding fit over the outside of the cylindrical portion  31 .  
         [0051]      FIG. 4  shows the lockring  50 , which is also a single piece of injection-moulded DELRIN. The lockring  50  is substantially cylindrical and has a mating end  54  and a non-mating end  52 . The internal surface of the lockring  50  includes a portion  56  of constant radius at the non-mating end  52 , the radius being such that this portion  56  is a sliding fit on the cylindrical portion  31  of the sleeve  30 . The internal surface of the lockring  50  also includes a mid portion  57  that is oblique to the axis of the lockring  50  such that the internal radius thereof increases from the portion of constant radius  56  to the mating end  54 . An inwardly-projecting lip  58  is provided at the mating end  54 . The lip  58  runs circumferentially around the inside of the lockring  50 . The radius of the lip  58  is such that it is an interference fit with respect to the ridge  49  of each arm  40  and such that it is a sliding fit on the mid portion  45  of each arm  40 .  
         [0052]      FIG. 1  shows an assembled arrangement of the connector part  10 , in which the radially innermost piece  20 , the sleeve  30  and the lockring  50  are fitted to one another so as to be co-axial. The radially innermost piece  20  is placed inside the sleeve  30  with the step  120  of the former abutting the step  130  of the latter. This results, as stated above, in the mating surface  27  of the radially innermost piece  20  projecting beyond the mating end  34  of the cylindrical portion  31  of the sleeve  30 . The lockring  50  is placed around the sleeve  30 , with the mating end  54  of the lockring  50  projecting in the same direction as the mating end  34  of the sleeve  30 . A circlip  60  is then placed in the circlip groove  39  of the sleeve  30  to retain the lockring  50  around the sleeve  30 . In operation, the one connector part  10  is connected to the other connector part  10 ′. The two connector parts  10 ,  10 ′ are presented to one another so as to be 90 degrees out of alignment, i.e. so that the arms  40  of the one connector part  10  interpose the arms  40 ′ of the other  10 ′. The two connector parts  10 ,  10 ′ are pressed together until the arcuate shallow flange  42 ,  42 ′ of each arm  40 ,  40 ′ has passed over the lip  33 ′,  33  of the respective other sleeve  30 ′,  30 . In so doing, the arms  40 ,  40 ′ bend radially outwards so that the shallow flanges  42 ,  42 ′ “latch” over the respective lip  33 ′,  33 . The shallow flanges  42 , 42 ′ come to rest in abutment against the respective lip  33 ′,  33 . Also, the arcuate shallow flange  42 ,  42 ′ of each arm  40 ,  40 ′ presses inwardly on the cylindrical portion  31 ′,  31  of the respective other sleeve  30 ′,  30 . Thus, the shallow flanges  42 ,  42 ′ act as catch surfaces. This provides both axial and radial location and results in the mating surface  27 ,  27 ′, and hence the o-ring seal  29 ,  29 ′ therein, of each radially innermost piece  20 ,  20 ′ being pressed firmly together so that a fluid tight seal exists between the two radially innermost pieces  20 ,  20 ′. This is the primary means of connection.  
         [0053]     Although not a feature of this embodiment, it is envisaged that a resiliently compressible member, such as a wave washer may be provided between the respective two abutting steps  120 ,  130 ;  120 ′,  130 ′ of each connector part  10 ,  10 ′. The characteristics of such a resiliently compressible member would affect the pressure between the mating surfaces  27 ,  27 ′ of mating connector parts  10 ,  10 ′ and resiliently compressible members may be selected with this in mind.  
         [0054]     Each lockring  50 ,  50 ′ is then pushed towards the respective other sleeve  30 ′,  30  so that the inwardly-projecting lip  58 ,  58 ′ of each lockring  50 ,  50 ′ passes over the tip portion  46 ′,  46  of each of the arms  4 O′,  4 O of the respective other sleeve  30 ′,  30 . In so doing, the arms  40 ,  40 ′ are deflected radially inwards until each inwardly-projecting lip  58 ,  58 ′ has passed over the ridge  49 ′,  49  of the respective arm  40 ′,  40 , whereupon the arms  40 , 40 ′ at least partially recover their shape. In this position, the inwardly-projecting lip  58 ,  58 ′ lies across the outermost surface of the base portion  45 ′,  45  of the arms  40 ′,  40  of the respective other sleeve  30 ′,  30 . Thus, the lockrings  50 ,  50 ′ serve to prevent the disconnection of the two sleeves  30 ,  30 ′ and hence of the two connector parts  10 ,  10 ′ by preventing the arcuate shallow flanges  42 ,  42 ′ from moving radially outwards so that they may pass back over the lip  33 ′,  33  of the respective other sleeve  30 ′,  30 . This is the secondary means of connection and may be considered an auxiliary mechanism to the primary means of connection.  
         [0055]     In this embodiment, the base portion  45 ,  45 ′ of each arm  40 ,  40 ′ is of a width such that, once mated, the base portions  45 ,  45 ′ form a complete cylinder of interposed arms  40 ,  40 ′. This provides angular location of the one connector part  10  relative to the other  10 ′ and also serves to provide additional radial location.  
         [0056]     It is envisaged that each inwardly-projecting lip  58 ,  58 ′ may be an interference fit against the base portion  45  of the respective arms  40 ′,  40  that are surrounded thereby. This would result in the arms  40 ,  40 ′ being continually pressed against the cylindrical portion  31  of the respective sleeve  30 , thereby further preventing unwanted disconnection.  
         [0057]     It will be appreciated that the connection operation as described above is accomplished by pushing first the sleeves  30 ,  30 ′ together and then pushing the lockrings  50 ,  50 ′ together. This is both simple and quick. The two connector parts  10 ,  10 ′ are disconnected by reversing the procedure described above. As described above, the connector parts  30 ,  30 ′ may have respective apparatus (not shown) connected to the radially innermost piece  20 ,  20 ′ of each connector part  10 ,  10 ′. For example, piping for carrying liquids and/or gases may be attached to each radially innermost piece  20 ,  20 ′. Alternatively, conduit for carrying electrical or some such other cable by be so joined. Mechanical drive shafts for rotary, linear or some such other form of motion may also be connected in this way. It is envisaged that alternative connecting means to that of the screw thread  26  may be used to connect one or both of the connector parts  10 ,  10 ′ to such apparatus.  
         [0058]     In an alternative and simplified embodiment, each identical connector part may not include a lockring, but may include only a respective radially innermost piece and sleeve, the radially innermost piece and sleeve being as described above.  
         [0059]     In another alternative and even simpler embodiment, each identical connector part may include the sleeve only. This other alternative embodiment might be suitable for an application in which fluid-tight sealing is not needed. Alternatively, it is envisaged that the mating end of the cylindrical portion of each sleeve may be provided with an o-ring seal, so that this other alternative embodiment might be used in applications where fluid-tight sealing is needed.  
         [0060]     An alternative embodiment is shown in  FIG. 5 . This includes a connector part  70 , which has a radially innermost piece  71  which is generally similar to the radially innermost part  20  and sleeve  30  described in  FIG. 1  above. In this embodiment, the engagement means is provided through a lock-ring  72  and arms  73  of the connector part  70 . The lock-ring  72  surrounds and restricts the arms  73  of the connecting part  70  to draw and hold the connector part  70  and mating connector part  70 ′ together. This engagement means is shown in more detail in  FIG. 6  and  FIG. 7 . Each arm  73  has a part cylindrical portion  74  which terminates in a radially protruding lip  76  at its mating end. The lip  76  has an annular, rear face  75  which extends along a helical path  77  and has a slight axial lead along the radially outermost surface of the cylindrical portion  74 .  
         [0061]     The lock ring  72  is shown in  FIG. 7 . The lock ring  72  comprises a generally cylindrical tubular member  85  which has a first inwardly directed, annular flange at its non-mating end  76   a , and a second inwardly directed annular flange at its mating end  76   b . The second annular flange has two angularly extending spaced cut out portions  80  which define angularly spaced flange portions  81 ,  81 ′. The angular extent of each cut out portion  80  corresponds to the angular extent of each arm  73 . The cutaway portions  80  are thus able to accommodate each respective arm  73  of the connector part  70  when the lock-ring  72  is slid over an opposing connector part  70 ′. The end face  82  of each flange portion  81  extends along a helical path at a slight axial lead and is thus complementary to the helical face  77  provided on the radially outmost surface of the cylindrical portion  74 .  
         [0062]     In operation, the one connector part  70  and the other connector part  70 ′ are presented to one another to form a complete cylinder of interposed arms as described above in relation to the first embodiment. Each lock ring  72  is then pushed towards the respective other connector part  70 ,  70 ′ so that an arm of the respective other connector part  70 ,  70 ′ is accommodated in each respective cutaway portion  80  such that each lip  76  is passed completely through the cut out  80 . Each lock ring  72  is then twisted through 90° around its longitudinal axis so that each lip  76  moves behind its associated flange portion  81  into the axial space between the flange  76   a  and flange portion  81 . During this operation, the helical face  75  of each lip  76  comes into frictional engagement with the helical face  82  of the associated flange portion  81  in order to lock the two together. Thus, the lock rings  72  serve to prevent the disconnection of the two connector parts  70 ,  70 ′ by preventing the arms  73  of each respective connector part from moving away from the opposing arms  73 ′ of the other connector part. Further, the complementary helical faces  75  and  82  serve to pull the mating surfaces  47 ,  47 ′ of the connectors together when they are engaged to ensure a tight seal.  
         [0063]      FIG. 8  shows a cross section through an olip seal  83 . The olip seal  83  is manufactured from a plastics or rubber material such a VITON. The olip seal  83  is toroidal and has an integral lip shaped protrusion  84  angled towards the toroidal axis. In use, an olip seal  83  is located in a groove in the mating surface  47  of each connecting part  70  such that the integral lip shaped protrusion  84  points away from the main body the connector part  70 . Thus, when in its connected state, opposing olips  83  form a tight seal by opposing lip shaped protrusions  84  being compressed against each other. The seal formed is thus able to withstand increased internal pressures, should they arise, by virtue of the resistance generated by the opposing lips shaped protrusions  84 .