Tube coupling bodies

[0002] This is a Continued Prosecution of application Ser. No. 09/116,279, filed Jul. 16, 1998, which is a continuation-in-part of application Ser. No. 08/669,086, filed Jun. 24, 1996, now U.S. Pat. No. 5,779,284 and a continuation of application Ser. No. 08/670,943, filed Jun. 26, 1996 now abandoned.

[0003] 1. Field of the Invention

[0004] This invention relates to tube coupling bodies of the type in which an open ended throughway has a resilient fingered collet to receive and hold an end portion of a tube inserted into the throughway.

[0005] 2. Background of Prior Art

[0006] My UK Patent Specification No 2,172,948 describes and illustrates a tap or valve body having a throughway to receive a tube which is locked in the throughway and is sealed to the bore by O-ring seals. The collet is encircled by an insert sleeve which is locked in the throughway by means of a collet having a plurality of resilient fingers. The collet is encircled by a plastics insert sleeve located in a counterbore at the end of the throughway and held therein by a spring ring embedded in the sleeve with an outwardly angled outer periphery to engage and grip the surface of the counterbore.

[0007] The angled outer periphery of the spring ring is almost entirely embedded in the insert sleeve which resists deflection of the ring as it is inserted into the counterbore. As a result, if the coupling body is formed on a soft plastics material, this is likely to be damaged on insertion of the sleeve reducing the effectiveness of the grip of the spring ring with the surface of the counterbore.

[0008] This invention provides a cylindrical attachment for locking in a bore the attachment having an external surface formed with an annular groove which has one side nearest one end of said attachment, and a metal grab ring embodied in the sleeve, said grab ring having multiple resilient fingers around an outer periphery of said ring projecting radially beyond the outer surface of the attachment and the ring being located adjacent said one side of said groove so that on insertion of the attachment into the throughway, the resilient fingers are flexed away from said one side of said groove and are thereby angled towards the other end of the attachment by engagement with a surface of the throughway, the flexing of the fingers being accommodated by the annular groove and the resilience of the fingers causing the fingers to grip said surface of the throughway to prevent attachment from being withdrawn from the throughway, the open end with one end of the sleeve located within the throughway and the other end at the end open of the throughway, the insert sleeve having a tapered internal cam surface reducing towards said other end of the sleeve with which fingers of a tube gripping collet are engageable to receive and lock a tube inserted into the throughway in the coupling body, the external surface of the sleeve having an annular groove and a metal grab ring embodied in the sleeve adjacent the side of the groove nearest said one end of the sleeve and having multiple fingers around its outer periphery projecting radially beyond the outer surface of the sleeve so that on insertion of the sleeve in the throughway, the resilient fingers are angled towards the other end of the sleeve by engagement with the surface of the throughway, the angling of the fingers being accommodated by the annular groove and the resilience of the fingers causing the fingers to grip with the surface of the throughway to prevent the insert sleeve from being withdrawn from the throughway.

[0009] The attachment may have an outwardly projecting encircling flange at said other end thereof which engages with the end face of the coupling body around the open end of the throughway to limit inserting of the sleeve into the throughway.

[0010] The attachment may have an external diameter corresponding to the internal diameter of the throughway and said annular groove is formed in the external surface of the attachment midway along the attachment.

[0011] FIG. 1 is an assembly view of a tube coupling including coupling body having a throughway for receiving a tube and an insert sleeve mounted in the throughway which a collet is locatable for receiving and locking a tube in the throughway;

[0012] FIG. 2 is a similar to view to FIG. 1 showing insert sleeve and collet prior to insertion in the coupling body;

[0013] FIG. 3 is a end view of a grab ring embodied in the insert sleeve of the sleeve in the coupling body; and

[0014] FIGS. 4 to 15 show further similar arrangements.

[0015] Referring firstly to FIG. 1 of the drawings, there is shown a tube coupling indicated generally at 10 and comprising a moulded plastics tube coupling body 11 having an open ended throughway 12 in which a tube end is engageable. Towards the open end of the throughway, the throughway is formed with a series of stepped counterbores comprising a first counterbore 13 providing an annular seat in which an end of a tube to be held in the coupling body is located, a second counterbore 14 in which an O ring seal 15 is mounted for sealing with the external surface of the tube and a third counterbore 16 at the open end of the throughway in which an insert sleeve 17 is mounted and in which a resilient fingered collet 18 is located to receive and grip the tube.

[0016] Reference is now made to FIG. 2 which illustrates the insert sleeve 17 and collet 18 prior to insertion in the counterbore 16 in the coupling body. To locate the sleeve, it is formed with out-turned flange 21 to engage the end face 22 of the coupling body 11. Between the end face 19 and flange 21, the insert sleeve has a cylindrical outer surface 23 which is a close fit in counterbore 16. Midway along the surface there is an annular rectangular section groove 24 and a grab ring 25 is embedded in the insert sleeve on the side of the groove 24 adjacent the side 28 of the groove nearest to end face 19 of the sleeve. The grab ring has a inner L-section annular portion 26 and a multiplicity of radial teeth 27 closely spaced around the annular portion. The grab ring is elevation in FIG. 3.

[0017] Prior to insertion of the insert sleeve 17 into the counterbore 16, the teeth 27 of the grab lie adjacent the side 28 of the groove nearest end 19 of the insert sleeve. On forcing the insert sleeve 17 into the counterbore 16, the teeth 25 are flexed by engagement with the surface of the counterbore away from the side 28 of the groove into the groove as shown in FIG. 1 and the resilience of the teeth holds the teeth firmly against the counterbore to resist extraction of the insert sleeve.

[0018] The inner side of the insert sleeve is formed with a tapered cam surface 30 extending from end 19 of the sleeve and terminating in an annular step 31 facing into the throughway. The tapered cam surface is engageable with heads 32 at the ends of resilient fingers 33 of the collet 18 to deflect the fingers inwardly as the collet is moved outwardly of the insert sleeve to cause the collet fingers to grip and engage a tube extending through the collet. The shoulder 31 at the reduced diameter end of the cam surface. 30 provides a stop with which the head 32 are engageable when a tube is present in the collet to prevent inadvertent extraction of the collet from the coupling body.

[0019] In the above described embodiments a tube coupling body has an insert sleeve locked in the body by means of a grab ring embedded in a groove in the outer side of the sleeve. The following is a description of a number of embodiments in which similar grab ring arrangements are used to lock different components in bores in bodies. In each instance, the components of the grab ring and groove in which it is mounted are given the same reference numerals as hitherto.

[0020] In the arrangement of FIG. 4, a plane tubular sleeve 50 has an enlarged annular head 51 at one end thereof. The head has an outer surface 52 in which the annular rectangular section groove 24 is formed with a grab ring 25 embodied in the head at one side of the groove. As before, the grab ring has an inner L-section annular portion to anchor the ring in the head and a multiplicity of radially spaced teeth 26 to engage the bore in the body in which the annular head is located to lock the bore in the head as described previously. The sleeve 50 can receive an end of a flexible tube or other component.

[0021] FIG. 5 of the drawings shows a similar arrangement to that of FIG. 4 except that the tube coupling is double ended having two projecting sleeves 50 with a central annular head 51 to lock in a bore in a body as described above.

[0022] FIG. 6 shows a further variant in which one side of the head 51 has an outwardly projecting flange 53 to form a stop limiting insertion of the head into a bore.

[0023] FIG. 7 shows a variant on the arrangement of FIG. 4 in which the external surface of the tube is formed with encircling ridges 54 to receive and grip a tube fitted over the sleeve.

[0024] FIG. 8 show a double ended version of the coupling body of FIG. 7.

[0025] FIG. 9 shows a further variation in which a sleeve 50 has an external screw thread 51 to which a tube with a screw threaded fitting at the end thereof can be coupled.

[0026] FIG. 10 shows a double ended version of the arrangement of FIG. 9.

[0027] FIG. 11 shows an annular socket 56 having an external encircling groove 20 and grab ring 25 mounted in one side of the groove to lock the socket in a bore in a body. The socket has a plane bore or an internal screw thread 57 as shown.

[0028] FIG. 12 shows a variation in which the socket 56 has an internal grab ring 58 to receive and lock a tube in the socket.

[0029] FIG. 13 shows a further variation in the form of a solid plug 59.

[0030] FIG. 14 shows a tube coupling body 60 having a throughway 61 open at both ends in which tube gripping collets 62 are mounted to receive and lock ends of tubes in the end of the coupling body. At the centre of the coupling body there is an enlarged head 63 having a rectangular groove 24 and grab ring 25 as described above for locking the coupling body the a bore in a component.

[0031] FIG. 15 shows a variation on the coupling body of FIG. 14 in which one end only of the coupling body has a collet 62 to receive and lock a tube therein, the other end having a plane bore 64 which may receive a further component.