QUICK CONNECTOR FOR FLEXIBLE TUBES OR PIPES WITH CONICAL RETAINING RING

Abstract: Quick connector for flexible tubes or pipes, which comprises a hollow body (1), equipped on the inside with a seating (2) for an annular seal (3), to which body is secured a collar (4) carrying a conical elastic ring (5) having radial slits open towards the inner edge, the ring diverging towards the free end of the body, into which conical ring there may be inserted a flexible tube (6) in sealing contact with the annular seal (3), which tube can be advanced towards the interior of the hollow body (1) with limited elastic deformation of the conical ring (5) and in conditions of jamming of said conical ring (5) when the tube moves outwards, there being also present a shell (8) projecting outwards from the body (1) and surrounding the flexible tube (6) and having a tapered end (11) towards the inside, the shell (8) being in contact with the internal edge of the slit conical ring (5) and being adapted for preventing, when pushed inwards into the hollow body (1), the jamming of the conical ring (5) on the surface of the flexible tube, thus making its withdrawal possible.

Description: The subject of the present invention is a quick connector for flexible tubes or pipes, capable of being disconnected, with retention of the tube by jamming means. For the connection of flexible tubes to fixed devices, such as valves, joint elements, reducers, user equipment and the like, connections of various types are used, for which it is required that they shall assure both the hydraulic or pneumatic seal and also the mechanical locking of said tubes. A fundamental requirement, especially in the case of the construction of plant of large dimensions, such as for example industrial or domestic hydraulic distribution systems, is that of enabling the connections to be made especially rapidly, without however detracting from the firmness and stability of the connection. In many cases, moreover, the flexible tubes or pipes used are subjected to dimensional variations, for example as a consequence of temperature fluctuations during operation, as in the case of heating or hot water distribution installations, or due to a drop in the ambient temperature; in such cases, as a result of an expansion, it is possible for the tube to depart from the path assigned to it, or for compression forces to act upon the end connections of the tube and, as a consequence of a contraction in the case where a departure from the path of the tube in a layout of short length is prevented, for example in the case of an initial straight layout, tensile forces act upon the end connections, which may also lead to disengagement of one end of the tube from the relevant connection. Many connections are known in the prior art as disclosed into US-A-4.288.113 and FR-A-1.474.023 that show connections that do not allow removal of the fixing ring of the sealing element or are not suitable for high pressure connection, anyhow in both solutions it is not allowed a relative movement between the fixed part and the inserted tube, movement particularly necessary for those uses where a high termic gradient takes place. The need therefore arises to provide a connection which shall assure a solid mechanical locking to the tube, which shall be capable of being disconnected in an especially rapid manner and which shall moreover be capable of assuring an axial deviation of the end of the tube without alteration to its mechanical connection or its hydraulic seal. Said results are achieved by the present invention, which provides a quick connector for flexible tubes and pipes, characterized by the fact that it comprises a hollow body, equipped in its interior with a seating for an annular seal, to which body there is secured a collar carrying a conical elastic ring having radial slits open towards its inner edge, the conical ring diverging towards the free end of the body, into which conical ring there may be inserted a flexible tube in sealing contact with the annular seal, which tube can be advanced towards the interior of the hollow body with limited elastic deformation of the conical ring and in conditions of jamming of said conical ring when movement of the tube occurs in the outward direction, there being also provided a shell projecting externally from the body and surrounding the flexible tube in which the collar seating carries integrally the conical elastic ring and is axially slidable within a sliding of the hollow body, between extreme stop positions defined in the hollow body with a distance of travel greater than or equal to the maximum dimensional variation envisaged for the flexible tube. More particularly the retaining ring is rigidly secured inside the hollow body independently of the collar and it is further provided that the retaining ring is axially linked to the body through a blocking ring inserted into a corresponding annular groove of the body itself. Further details will be apparent from the following description, given with reference to the attached drawings, in which there are shown: in figure 1, a connector according to the prior art in axial section, designed for connecting copper pipes; in figure 2, the known connector of figure 1, in an alternative form of embodiment; in figure 3, a connector according to this invention, in axial section, provided with a facility for compensating expansions. With reference to figs 1 and 2 showing connectors known in the prior art the connector for securing a tube of the flexible type to a fixed member such as in the case of domestic hydraulic installations, is composed of a hollow body 1 of substantially cylindrical form, firmly fixed to the apparatus to which the tube is to be connected, inside which hollow body is formed a seating 2 for a toroidal seal 3; a collar 4, secured to the body 1, carries a conical elastic ring 5 having radial slits open towards the inner edge, shown in unsectioned view in the left half of figure 2. The slit conical ring 5, diverging towards the free end of the body 1, receives inside itself the end of a tube 6 as a result of the elastic bending of the strips 5a defined by the radial slits, thus allowing insertion of the tube into the body 1 as far as its internal annular stop projection 7, but resists, by jamming or wedging action of said strips 5a on the surface of the tube, subsequent withdrawal of said tube, thereby assuring its retention in position; the hydraulic seal of the joint is guaranteed by the sealing ring 3. Inside the collar 4 there is also present a slidable shell 8, equipped with an annular ridge 9 which forms a stop against a corresponding internal shoulder of the collar 4, adapted for preventing its retraction outwards, and with a bearing flange 10, by which the shell 8 can be pushed with its tapered end 11 into contact with the inner edge of the strips 5a of the ring 5, thereby causing the ring to expand and allowing the tube 6 to be withdrawn from the body 1. In this manner, the operations of engagement and disengagement of the tube into and from the body 1 are rendered extremely simple and rapid, without however prejudicing the mechanical firmness and stability of the joint. The tube 6 may be of metal, for example copper, or may be of plastics material having suitable mechanical characteristics for the intended use, such as for example polypropylene, suitable for use in domestic hydraulic installations and the like. For retaining the seal 3 in its seating, a retaining ring 12 is provided; said ring can be fixed in the axial direction by the collar 4. In the form illustrated in figure 1, the ring 12 is a flat ring and the collar 4 possesses axial fins 13 bearing against it; the fins 13, as can be seen more clearly in the right half of figure 1, are deflected inwards by a small angle and alternate with fins 14 having a greater deformation, by means of which the conical ring 5 is secured to the collar 4, at a sufficient distance from the retaining ring 12 to allow the deformation of the conical ring during the engagement and withdrawal of the tube or pipe 6. The fins 13 may also be helically twisted, assuring with their less deformed edge the securing of the retaining ring 12 and with their opposite edge, having a greater bend, the securing of the conical ring 5; in this case it is not necessary to provide fins 14 for blocking the conical ring 5. Alternatively, the retaining ring 12 may extend axially towards the collar 4, for example possessing a cylindrical portion 15 as illustrated in the left part of figure 2, or being formed with a greater thickness, as illustrated in figure 2 in the right part; in such cases the securing in position of the ring 12 and of the conical ring 5 is ensured by tightening of the rings as a unit against an internal stop surface 16 of the body 1, by means of the collar 4. The seating 2 for the seal 3 may also be constructed in the form of an annular groove inside the body 1, closed on three sides, and in this case there is no requirement for providing a retaining ring. The collar 4, in turn, may be secured to the body 1 by a force fit, as indicated in figure 1 and in the left part of figure 2, or may be secured by adhesives or again by screwing, by means of associated screw threads 16, as illustrated in the right part of figure 2. A connection according to the present invention is shown into fig. 3, in fact in the case where the tube or pipe 6 is subject to considerable variations in dimensions, for example due to temperature changes, as in the case of tubes of plastics material, the collar 4 is made slidable inside the body 1 as illustrated in figure 3, inside a sliding seating 17 bounded at the outside by a rim or flange 18 or the like, which prevents withdrawal of the collar 4; the conical ring 5 is secured to the collar 4 for example by means of a bent-over flange 19. In this embodiment, the retaining ring 12 for the seal 3 is secured in position independently of the collar 4, for example by means of a force fit inside the body 1 or, as indicated by broken lines in figure 3, by a retaining ring 20 inserted into a suitable groove. This arrangement allows the collar 4, holding the tube 6 secured by means of the ring 5, to slide inside the hollow body 1 as a consequence of axial expansions or contractions of the tube, thereby avoiding the transmission of loads to the body 1 or the causing of deformations or inflections to the tube. For this purpose, the tube 6, which usually at the time of assembly is in an intermediate position of its dimensional travel, is mounted inside the ring 5 without coming into bearing against the bottom projection 7, as indicated in full line in the left part of figure 3, stopping at a certain distance from this projection; as a result of a subsequent expansion, for example when the maximum operating temperature is reached, the tube can slide inside the ring 5 until it is near the projection 7. A subsequent contraction of the tube 6, for example when the minimum operating temperature of the plant is reached, leads to sliding of the collar 4 in the outward direction inside its seating 17, withdrawal of the tube being prevented by the ring 5, as shown in the right part of figure 3. The shell 8 is made of sufficient length to allow the required sliding distance. In the case where the tube 6 is fitted into the hollow body 1 in conditions of maximum extension of said tube, for example when the tube is at the maximum intended operating temperature or is under axial tension, the tube may be inserted into the ring 5 until it comes into bearing against the projection 7.

Claims: Quick connector for flexible tubes or pipes, comprising a hollow body, (1) internally equipped with a seating (2) for an annular seal, (3) to which body there is secured a collar (4) carrying a conical elastic ring (5) having radial slits open towards its inner edge, the ring diverging towards the free end of the hollow body, (1) inside which conical ring (5) there may be inserted a flexible tube or pipe (6) in sealing contact with the annular seal, (3) which tube can be advanced towards the interior of the hollow body (1) with limited elastic deformation of the conical ring and in conditions of jamming or wedging of said conical ring (5) when outward movement of the tube occurs, there being also provided a shell (8) projecting outwards from the body (1), surrounding the flexible tube (6) and having its inward (9) end tapered and in contact with the inner edge of the conical ring, (5) the shell (8) being adapted for preventing, when it is pushed inwards into the body (1), jamming of the conical ring (5) on the surface of the flexible tube (6), characterized by the fact that the collar (4) carries integrally the conical elastic ring (5) and is axially slidable within a sliding seating (17) of the hollow body, (1) between extreme stop (18) positions defined in the hollow body (1) with a distance of travel greater than or equal to the maximum dimensional variation envisaged for the flexible tube. Quick connector for flexible tubes or pipes according to claims 1, in which the seating (2) for the annular seal (3) comprises a retaining ring (12) blocking the annular seal (3) towards the outside of the hollow body, characterized by the fact that the retaining ring (12) is rigidly secured inside the hollow body (1) indipendently of the collar (4). Quick connector for flexible tubes or pipes according to claim 2 characterized by the fact that the retaining ring (12) is axially linked to the body (1) through a blocking ring (20) inserted into a corresponding annular groove of the body itself.

Inventors: CERIANI, GIULIANO
Applicants: FINIMPRESA S.R.L.
Application year: 1988
Main classification: F16L37
IPC codes: F16L37