Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L19/00—Joints in which sealing surfaces are pressed together by means of a member, e.g. a swivel nut, screwed on or into one of the joint parts
  • F16L19/08—Joints in which sealing surfaces are pressed together by means of a member, e.g. a swivel nut, screwed on or into one of the joint parts with metal rings which bite into the wall of the pipe
  • F16L19/083—Joints in which sealing surfaces are pressed together by means of a member, e.g. a swivel nut, screwed on or into one of the joint parts with metal rings which bite into the wall of the pipe the longitudinal cross-section of the ring not being modified during clamping
  • F16L19/086—Joints in which sealing surfaces are pressed together by means of a member, e.g. a swivel nut, screwed on or into one of the joint parts with metal rings which bite into the wall of the pipe the longitudinal cross-section of the ring not being modified during clamping with additional sealing means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L19/00—Joints in which sealing surfaces are pressed together by means of a member, e.g. a swivel nut, screwed on or into one of the joint parts
  • F16L19/06—Joints in which sealing surfaces are pressed together by means of a member, e.g. a swivel nut, screwed on or into one of the joint parts in which radial clamping is obtained by wedging action on non-deformed pipe ends
  • F16L19/065—Joints in which sealing surfaces are pressed together by means of a member, e.g. a swivel nut, screwed on or into one of the joint parts in which radial clamping is obtained by wedging action on non-deformed pipe ends the wedging action being effected by means of a ring

Definitions

• the present invention relates to a joint for connecting pipes composed of a body provided at least at an end with an outer thread; a cylindrical seat for inserting the pipe inside said body; a ring nut intended to be screwed at the end of said body on the thread, said ring nut being provided with an inner conical surface; at least a clamping ring with an outer shell surface that is at least partially conical and intended to cooperate with the inner conical surface of said ring nut and which ring internally has teeth intended to grip the end of the pipe inserted in the joint and said ring having the possibility of being tightened by means of a radial restriction caused by the ring nut being screwed on the body, at least a seal between the cylindrical seat of the joint and the outer wall of the pipe. Joints of this type are known and widely used.
• the pipe is introduced into the joint which is in its pre-assembled condition and with the tightening ring nut already screwed on the thread.
• the tightening ring nut is in an initial screwing condition wherein the clamping ring is not compressed against the pipe for clamping it into the joint yet, while the seal has such a diameter to allow the pipe to slide inside it generating a frictional resistance that can be easily overcome by a manually applied force. Therefore the pipe can slide inside the clamping ring and the seal being brought in the proper coupling position into the joint body.
• the pipe Once the pipe has reached the complete coupling position, it is mechanically clamped by screwing the tightening ring nut acting on the clamping ring by means of respective conical surfaces .
• the tightening ring nut can be also provided for the tightening ring nut to exert an axial compression on the seal by means of the axial movement along the joint body that is transmitted to the clamping ring and in this case it acts also as seal pushing means .
• the inner conical surface of the ring nut is pushed to contact the conical surface of the end of the clamping ring so when the ring nut is screwed the axial advance of the ring nut causes a radial constriction of the clamping ring gripping the pipe wall by a series of conical inner teeth due to the relative sliding motion of two conical surfaces of the above mentioned two parts .
• Joints for pipes commercially available have a type of clamping ring, whose inner diameter is slightly smaller than the outer diameter of the pipe therefore said ring is elastically deformed, i.e. it is slightly widened, when the pipe is inserted in the joint and such deformation causes an intrinsic force for the elastic returning action in the original/not stressed position to be generated by means of which, inner teeth of the ring, by gripping the outer surface of the pipe allow the ring to be firmly tightened thereon.
• the above clamping ring carries out its function by its physical structure/shape, being composed of a ring, usually a plastic one, having an axial open slot at both head sides.
• the clamping ring is inserted by forcing it on the pipe and this leading to: both a certain difficulty for inserting the pipe in the joint, and the fact that, when the pipe is taken out from the joint, such ring remains clamped on the pipe, since the gripping action of teeth thereof does not allow the ring to slide on the outer surface of the pipe, towards the end thereof housed in the joint.
• a further drawback of joints actually on the market is the fact that the clamping action by the ring on the pipe cannot be easily reproduced.
• This drawback is caused by two facts: the first one is that the ring is clamped on the pipe by two forces: an intrinsic elastic return force, previously described, that can clamp the ring on the pipe in a wrong position, and a tightening force by the radial restriction deriving from the tightening/pressing action determined by screwing the ring nut on the body.
• the second fact is that due to the coupling action the clamping ring/ring nut that is generally made with a conicity of about 8-10 degrees causes also a very high screwing length on the body.
• the angle of inclination of conical walls with respect to the central axis of the cone defined by said conical walls defines the travel of the ring nut necessary to tighten the pipe in its clamped condition.
• An acute angle, so wherein the conicity is relatively small, i.e. conical surfaces are slightly inclined with respect to the central axis of the cone defined by said conical walls results in a relatively low torque for screwing the ring nut, but the travel necessary for obtaining a sufficient tightening action is relatively long so the ring nut has to be turned a lot of time when screwing it.
• the aim of the present invention is to provide a joint for connecting pipes able to overcome in a simple and inexpensive way above drawbacks of commercially used joints.
• the invention achieves the above aims by providing a joint whose clamping ring has an intrinsic elastic force for firmly maintaining a condition wherein its inner diameter is slightly greater than the outer diameter of the pipe or however it is such that the latter can be inserted by an axial sliding action without any impediments in the clamping ring, and said clamping ring can be elastically deformed narrowing the inner port delimited by the ring against the action of said elastic force in a condition with the diameter reduced with respect to the diameter in its resting condition, at such an extent that teeth of the ring grip the outer surface/wall of the pipe by firmly clamping it inside the joint, said reduction being generated by the action of the conical surface of the ring nut on the conical surface of the clamping ring during the screwing action.
• the clamping ring has two crowns of opposite axial slots and they are open alternatively on one of the two opposite head sides so to give the plane development of the shell surface of the clamping ring a shape that can substantially resemble a linked series of letters S.
• a first crown of separating axial slots is composed of slots such to form a crown of axial tongues retained on a material continuous annular support and such tongues can be circumferentially compressed against the outer surface of the pipe, said slots being open only at one of the head sides of the ring.
• a second crown of axial slots comprises at least one or more intermediate axial slots provided at a median position of each axial tongue formed by the above first crown of slots.
• Intermediate slots of said second crown of slots are open at the side opposite to the preceding ones and have such a depth in the body of the axial tongues that is enough to guarantee a certain circumferential elasticity.
• These radial changes obviously occur toghether with restrictions or extensions i.e. shortenings and/or elongations of the circumference of the clamping ring due to the presence of axial slots and particularly of the two axially opposed crowns .
• Slots have such an axial length that they end beyond a circumference provided in an intermediate position and particularly in the median position of the axial length of the clamping ring.
• This arrangement advantageously allows to have different changes of the radius of the two axial ends of the clamping ring so that it may take a condition wherein the shell wall conically becomes widener from one end to the other head end or vice versa it becomes conically narrower from said one to said other end.
• the present joint has an initial entrance region having a diameter greater than the outer diameter of the clamping ring and an annular groove for fitting an annular tooth retaining the clamping ring which tooth engages by snapping in the groove by retaining the clamping ring in a condition engaged in the body, with a predetermined retaining force and such that the ring can be disengaged from the body by a manual action.
• said clamping ring by means of the presence of the second crown of axial slots and by means of the behaviour of the clamping ring under the elastic compression or extension stress, said clamping ring, is slightly elastically circumferentially deformed that is its inner port is slightly narrowed, still however guaranteeing an inner diameter of said port greater than the outer diameter of the pipe. Said slight circumferential deformation of the side of the ring intended to be inserted in the body of the joint, i.e.
• the side of the ring having on its outer shell surface the annular retaining tooth causes the tongues of the clamping ring projecting towards the entrance side of the body to slightly outwardly open wide with respect to the central axis of the joint obtaining a flower- like opening whose petals are composed of tongues of the clamping ring.
• Such configuration gives the pipe a port, when it is inserted, having a greater diameter with respect to the inner diameter of the clamping ring in the resting condition with the ring inserted in the body.
• the force coupling the ring in the body is such that it is greater than the force generated by possible slipping effects of the pipe when it slides .
• the clamping ring on its outer surface, particularly at the end of the ring intended to elastically interact with the annular fitting groove in the inner wall of the seat for the insertion of the pipe, has a projecting annular tooth.
• the opposite end of the outer surface of the ring i.e. the end intended to elastically interact with the ring nut, has a wedge-like or conical inclined surface, which wedge-like or conical surface has the same inclination or an inclination consistent with the inner conical surface of the ring nut that interacts when it is screwed on the body.
• the clamping ring on its inner surface, at the end intended to clamp the pipe in the joint, has one or more teeth that make one or more series of crowns of teeth.
• said peaks of teeth making the one or more series of crowns of teeth of the clamping ring preferably lie on two or more axially adjacent circumferences and said circumferences are concentric having such diameters that progressively reduce their own value from the outermost crown of teeth, i.e. the one at the end of the clamping ring, to the innermost one.
• a first embodiment of the present invention provides mutual abutting conical surfaces and that is the inner one of the ring nut and the outer one of the clamping ring provided at the end thereof outside the seat of the pipe in the body of the joint, to have a relatively abrupt inclination and comprised between 25 and 40° preferably about 30°.
• This relatively abrupt inclination of the conical surface (corresponding to an opening angle of the cone of 60°) it is possible to obtain a sealing tightening of the joint on the pipe by a screwing rotation of the ring nut of about half a turn. This is particularly advantageous as regards the speed of intervention especially under uncomfortable working conditions .
• the short rotation of half a turn is also for loosening the joint from the tightened condition of the pipe to freely take out the pipe from the joint.
• the lower radial compression force exerted by the ring nut on the tongues of the clamping ring, with respect to a lower inclination of the cooperating conical surfaces of the clamping ring and of the ring nut, is compensated for the fact that by means of the particular flower-like configuration of the clamping ring, in the not tightened condition of the joint but in its mounted condition, the tongues are arranged as to be open wide and the radial compression action exerted thereon by the ring nut resembles to an oscillation of said tongues, so that when on the tongues two or more crowns of inner radial teeth are provided which are arranged along one of two or more circumferences respectively having a different axial position with respect to the extension of said tongues, the compression exerted by the ring nut on the tongues causes one of the two or more crowns of teeth to grip the pipe at a time and in a progressive way with reference to the axial direction towards the end of the clamping ring cooperating with the ring nut.
• a second embodiment of the present invention provides a joint of the type described hereinbefore wherein the conical surface at the head end of the clamping ring faced towards the tightening ring nut and the inner conical surface at the end of the tightening ring nut opposite to the threaded portion of the joint body have two adjacent portions having a different inclination with reference to the central axis of the pipe and/or tightening ring nut and/or clamping ring, a first portion of said conical surface, at the end of the clamping ring and at the corresponding end of the tightening ring nut, having an inclination (with respect to said central axis of the pipe and/or ring nut and/or clamping ring) that is greater than the inclination of a second portion of the conical surface to which said first conical surface portion is connected in the direction of the threaded portion of the joint body, i.e. in the direction for introducing the pipe into the joint.
• the inclination of the second conical surface portion is substantially the same both as regards the conical surface of the tightening ring nut and as regards the conical surface of the clamping ring.
• the inclination of the first conical surface portion of the tightening ring nut on the contrary is different from and slightly lower than the inclination of the first conical surface portion of the clamping ring.
• the first conical surface portion is connected to the second conical surface portion by a rounded or beveled arcuate portion, while as regards the tightening ring nut the two first and second conical surface portions are connected by an angle.
• the first conical surface portion has an inclination with respect to the central axis of the pipe and/or tightening ring nut and/or clamping ring greater than 30° and lower than 80°, and preferably it is from 40° to 60°, particularly from 45° to 50°.
• the second conical surface portion has an inclination lower than 40°, preferably lower than 30° and particularly from 10° to 30°.
• Second conical surface portions having the lower inclination or conicity allow teeth of the clamping ring to be pushed into the pipe wall by a relatively poor effort, resulting in a first effective gripping of the ring on the pipe, and in addition it results in an axial travel for compressing the annular seal, while once such condition is obtained, the additional compression of teeth of the clamping ring into the pipe wall is achieved firstly by means of hydraulic pressure of the fluid when exceeding a certain pressure completing the gripping action caused by the first cone and then by a short tightening travel since such effect is obtained when the tightening ring nut and the clamping ring cooperate one with the other with corresponding first greatest conical surface portions , even when the movement tightening the ring nut is completed.
• said first conical surface portions have a greater conicity leads to a greater retaining action of the pipe in the direction withdrawing it when the inner pressure reaches very high values or under strong mechanical pulling conditions of the pipe applied to the joint.
• a possible movement of the pipe with respect to the joint due to the inner pressure or to the pipes being pulled from the joint automatically causes teeth of the clamping ring to highly increase their compression in the pipe wall and so to increase the force or resitence clamping the pipe.
• a seal of the pipe inside the joint which seal is housed in a suitable seat obtained inside the body, and in the resting condition, i.e.
• the annular seal for example is of the 0-ring type or the like. Said annular seal is housed in an enlargement of the seat
• An embodiment of the invention provides the seat of said annular seal of the 0-ring type or the like to be composed of a radial enlargement of the seat of the pipe in the body of the joint which enlargement has a slightly conical shell surface which conical shell surface ends by an annular shoulder at the end opposite to the one for inserting the pipe.
• the smallest diameter of said conical narrowing or reduction is however greater than the outer diameter of the pipe and the conical shell surface has an axial length that is slightly greater than the diameter of the cross section of the 0-ring annular seal.
• axial pushing means provided in the joint act on the seal, are automatically driven by the tightening movement of the ring nut and they push the seal against the annular shoulder at the end having the smallest diameter of the conical shell surface of the seat of the seal, while diametric size of said conical shell, of the pipe and of the seal are such that with under the not tightened condition the pipe can freely axially slide in the seal and with the joint in its tightened condition the seal is tightly forces in the narrowing portion between the pipe and the wall of said narrowing and it is elastically circumferentially deformed so that its inner diameter is smaller than the outer diameter of the pipe.
• the seal of the O-ring type or the like can elastically return in its initial position i.e. in the conical narrowing portion having the greatest diameter and such elastic return occurs either spontaneously, or at least partially by means of the drawing action of the pipe when it is taken out from the joint.
• a friction between the annular seal and the pipe and the annular seal and the opposite conical shell surface of the seat of the seal is originated.
• the configuration of said seat of the annular seal of the 0-ring type being slightly conical and having a length close to the diameter of the longitudinal section of the annular seal, when the pipe is taken out from the joint, said seal recovers its initial position i.e.
• An alternative variant embodiment of the invention provides the seat of said annular seal of the O-ring type or the like to be composed of an inner annular radial shoulder making an abutment radial surface for the seal.
• Such radial abutment surface is oriented radially from the axis of the pipe and it is faced towards the tightening ring nut that is it is faced in a direction opposite to the direction introducing the pipe, while the seal is housed in an inner radial groove in the shell wall of a coupling union for the pipe.
• Such groove is delimited at the side opposite to the annular shoulder, of said coupling union, by a radial narrowing composed of two opposing conical surfaces , the conical narrowing surface faced towards the annular abutment shoulder being a surface for wedging the annular seal when said seal is pushed in the direction withdrawing the pipe.
• the difference between the outer diameter of the pipe and the inner diameter of the seal is from 0,5 mm to 3 mm, particularly from 1 to 2.
• the radial groove has such a diameter that the seal housed in said groove and in its resting condition has an inner diameter that is slightly shorter than the outer one of the pipe the difference being such that the pipe can be introduced inside the union and through the tight seal without too much resistence.
• the annular narrowing has a radial projection of 0.1 to 0.5 mm, preferably from 0,2 to 0,4 mm in the direction of the joint or the chord of the 0-ring.
• the shell conical surface has an axial lenght that is slightly greater than the diameter of the cross- section of the 0-ring annular seal. With the joint not tightened, the annular seal is housed in the portion having the greatest diameter. According to a further embodiment of the present joint the seal of the pipe inside the joint, in its resting condition, i.e.
• said seal can elastically take again its original resting shape either in a spontaneous manner or by means of at least partially the action dragging the pipe when it is withdrawn from the joint and under such condition it allows the pipe to slide being withdrawn from the joint without interacting with said seal thus not deforming it.
• one of the main advantages of the present invention is the joint tightened on the pipe being intended to absorb axial movements due to such high pressures of the fluid and also to use them and said withdrawing movements in order to generate a condition increasing the clamping force and/or the sealing condition.
• Still another variant embodiment of the joint according to the present invention provides the annular seal to be of the lip type or the like .
• Said lip seal has a base ring and an extension/lip attached to an end of the inner surface of the base ring.
• the seat of the annular lip seal is composed of a cylindrical wall and an annular axial abutting shoulder of the base ring.
• the inner surface of the base ring is cylindrical or if necessary slightly conical for allowing the elasticity to increase and also the elasticity to be adjusted.
• Said abutting shoulder of the base ring of the lip seal has an abutting surface that is preferably slightly inclined with the inclination having a direction equal to the direction of the conical surface of the ring nut.
• the base ring of the lip seal has a cross section that resembles a right-angled trapezium which oblique side has such an inclination to be complementary with the annular abutting shoulder of the seal on the body.
• the inner diameter of the base ring of the lip seal when it is not stressed, is greater than the outer diameter of the pipe, while the inner port delimited by the lip of said seal, has an inner diameter smaller than the outer diameter of the pipe, but it is such that when the pipe is inserted in the body the lip of the seal cooperates with the outer surface of the pipe but only by means of a slipping action so that the lip, of said lip seal, does not lead to a physical impediment for inserting the pipe in the body of the joint so it is freely inserted in the joint. This is also in the case if the joint is not thightened when the pipe is taken out from the joint.
• the radially outer surface of the lip of the lip of the seal overlaps the radially inner surface of the base ring of said seal, thus forming a kind of circular space with a wedge- shaped cross section between said two surfaces; at the same time the radially inner surface of the lip, rests against the outer surface of the pipe without preventing it to be easily taken out from the body, while with the joint tightened on the pipe, there are provided suitable pushing means which axially act on the base ring of the seal by pushing it against the annular abutting shoulder of the body and by circumferentially expanding it, which espansion leads to a pressure on the lip of the seal allowing the inner surface of said lip to adhere by a pressing action against the outer surface of the pipe so to generate the desired hydraulic sealing effect.
• the inclination of the surface of the annular abutting shoulder makes a kind of compression such that, the elastic deformation of the base ring following it leads to a deformation of the inner surface of the base ring of the seal.
• the circular space having a wedge-shaped section is flooded by the fluid, that, by acting on the inner surface of the lip of the seal, pushes said lip against the outer surface of the pipe, thus coopoerating with the pushing action of the base ring following the elastic deformation thereof made by pushing means, thus increasing the hydraulic sealing effect of the seal.
• the intensity of the action of the fluid on the inner surface of the lip, of the lip seal it substantially directly proportional to the pressure of the fluid inside the pipe therefore an increase of the action of the liquid pressure on the lip can be associated to an increase in the pressure of the fluid in the pipe consequently increasing the hydraulic sealing effect.
• the lip seal can elastically and spontaneously recover its initial shape under not stressed conditions, thus allowing the pipe to be taken out from the joint without any mechanical and/or excessive friction impediments .
• both of the 0-ring type or the like or of the lip type are composed of the combination of the ring nut and the clamping ring which have conical or cylindrical cooperating surfaces that cooperate one with the other when the ring nut is screwed on the body.
• the clamping ring is elastically circumferentially tightened against the outer surface of the pipe and at the same time it is axially pushed inside the body.
• the material composing the clamping ring has an hardness greater than the one of the material composing the pipe.
• Such technical solution is absolutely necessary for causing teeth of the axial crowns of the clamping ring to grip the outer surface of the pipe .
• the axial movement of the clamping ring inside the body leads the ring to be axially pushed/compressed against the annular seal.
• the body can be provided with limit stops for screwing the ring nut.
• Such screwing limit stops are composed of one or more surface abutment projections constituting indicators and/or limiting means of the screwing travel of the ring nut on the body, which indicators and/or limiting means allow the user of the joint to tighten the ring nut on the body such to always guarantee the optimal operation of the joint.
• the body can be provided with means for temporary positioning and retaining the ring nut partially screwed on the joint body and wherein the pipe can be inserted into the joint through the ring nut, the clamping ring and the seal that, under such partial screwing condition, have an inner diameter greater than or substantially equal to the one of the pipe and being such to allow it to pass without an excessive effort, which means retain the ring nut under said partial screwing condition in a temporary way and by force that can be manually overcome.
• said means are composed of at least a radial projection in the trajectory corresponding to the peak of an outer thread of the coupling union for the pipe, which projection can be elasically deformed by a predetermined manual force and which projection cooperates with engaging nothces or grooves provided at the head side of the tightening ring nut faced towards the joint body.
• said projection or projections have a protrusion slightly greater than the depth of grooves of the inner thread on the tightening ring nut, therefore the engaging interaction of said projection or projections is in the area of the head side of the tightening ring nut, while once said projections penetrate into the ring nut thread they freely move into grooves of said inner thread being elastically bent and resulting in a slight friction.
• the joint of the present invention is provided with anti-rotational means preventing the ring nut from being unscrewed once it reaches the predetermined tightening stop position.
• said anti-rotational means are composed of one or more radial teeth having the front faces faced towards the ring nut at a radial plane that is slightly upstream than the radial plane where the head side of the tightening ring nut faced towards the joint body falls once the ring nut is in the final tightening position, said radial anti-rotational tooth or teeth beingn engaged in corresponding recesses or nothces provided in the head side of the tightening ring nut, said teeth being provided beyond the end of the threaded portion.
• Particularly anti-rotational teeth have a lower elastic deformability than projections for temporary positioning and retaining the ring nut in its partial screwed condition, while engaging recesses or nothces of the ring nut can be the same cooperating both with temporary retaining projections and with anti- rotational teeth .
• fastening/anchoring means generally represented by a further thread, which fastening means allow the joint to interact with other devices for example valves, or T or elbow joints, or still other joints of the type previously described, and of the type commercially available in order to allow two final sections of pipes having different sections or composed of different material to be coupled.
• the body thereof is internally made such to have at least two abutting shoulders of the pipe end having an inner diameter slightly smaller one with respect to the other. Due to this inner configuration of the body, the same joint can be used for pipes having different diameters without changing neither the sealing ring, nor the annular seal, since due to the characteristics of the joint that have been previously described, both the clamping ring, and the annular seal have the possibility to change, within material limits allowed thereto, their inner port, thus to be adapated to clamp/retain also pipes having different diameters .
• the present joint has the possibility of being used not for only one pipe having a specific outer diameter, but is can be used for at least two pipes having different outer diameters , even if slightly differing one from the other .
• Fig.l is a section view of an half of a joint with the clamping ring engaged in the joint in its condition not tightened on the pipe.
• Fig.2 is the clamping ring engaged in the joint in its tightened condition on the pipe.
• Figs . 3 and 4 are a side view of the clamping ring and a top view thereof respectively.
• Fig.5 is a detail of the clamping ring.
• Fig.6 particularly is the position of the annular seal of the 0-ring type or the like with the joint in its not tightened condition.
• Fig.7 is a detail of the position of the annular seal of the 0-ring type or the like with the joint tightened on the pipe.
• Fig.8 particularly is the position of the lip seal with the pipe not inserted in the joint.
• Fig.9 is the position of the lip seal with the pipe in the inserted condition wherein the joint is not tightened on the pipe.
• Fig. 10 particularly is the position of the lip seal with the joint tightened on the pipe.
• Fig.11 is a section view according to a diametral plane of an alternative embodiment of the joint and with the pipe in the withdrawn condition .
• Fig.12 is a section view of the joint of Fig.11 wherein the pipe is in a first partial position inside the joint, the ring nut and the clamping ring being already assembled on the joint body with the ring nut screwed on the joint body wherein said ring is completely open and said condition of the pipe and joint corresponding also to a condition with the pipe partially withdrawn from the joint.
• Fig.13 is a section view like fig.12 and wherein the pipe and the joint are in a second position wherein the pipe is completely inserted into the joint body and the ring nut is only partially rotated such to cause the ring to be in the initial tightening condition on the pipe .
• Fig.14 like figures 12 and 13 is the pipe and the joint in a third position, wherein the ring nut is completely screwed on the joint till the ring nut completely abuts against limit stops means provided on the joint body.
• 15 is a view like previous figures with the joint and the pipe in a fourth condition wherein the pipe is moved in the withdrawing direction with respect to the complete introduction position into the joint body because of hydraulic pressure or a pulling action exerted on the joint, while the clamping ring by the portion having an abrupter inclination with respect to the axis of the pipe cooperates with the corresponding portion of the ring nut having a correspondingly abrupter inclination with respect to the axis of the pipe and while the 0-ring seal is more wedged between the outer wall of the pipe and a portion of the seat conically narrowing in the withdrawing direction of the pipe from the joint body.
• Fig.16 is an enlarged detail of the seal seat with the seal in the position of figure 15.
• Fig.17 is a perspective view of the sleeve forming the joint body and wherein limit stop abutment means provided on the joint body and means for temporary stopping the free rotation of the ring nut on the thread of the joint body by a frictional locking action can be seen.
• the body of the joint has a union 101 for coupling the pipe 5 having an outer thread 201.
• the union 101 has an inner shoulder 301 being a radial abutment surface for an annular seal 11 of the 0-ring type.
• the inner annular shoulder 301 is also a side wall of a seat housing said annular seal in the form of a groove made in the inner surface of the coupling union 101.
• the pipe is retained in place by a clamping ring 2 by an intrinsic elastic force firmly keeping it under a condition wherein its inner diameter is slightly greater than the outer diameter of the pipe 5, in its resting condition, i.e. with the pipe not tightened into the joint. Therefore the pipe can be inserted into the clamping ring 2 with no physical obstacles.
• the clamping ring 2 is tightened on the pipe by means of a tightening ring nut 4 whose inner thread can be screwed on the outer thread of the coupling union 101.
• a tightening ring nut 4 whose inner thread can be screwed on the outer thread of the coupling union 101.
• Particularly fig.l shows the joint in its not tightened condition.
• the clamping ring 2 even if the clamping ring 2 is engaged in the body 1 , however it has an inner diameter that is slightly greater than the outer diameter of the pipe 5.
• the clamping ring has one or more crown of teeth 6. These teeth have no interaction with the pipe 5 when the joint is in its not tightened condition so that upon the introduction of the pipe 5, it is not subjected to any physical impediments by the clamping ring 2.
• the clamping ring 2 has snapping means for the engagement by applying a slight external pressure in the body 1.
• Said means are composed of a projecting tooth 7 obtained on the outer shell surface of the clamping ring 2, which projecting tooth 7 engages in a suitable annular fitting groove 8 obtained on the inner surface of the body 1 by this arrangement.
• Said clamping ring 2 is firmly retained in the body 1 by a predetermined retaining force, which is however greater than the force generated by possible slipping actions when the pipe 5 is taken out from the joint, so the ring 2 can be disengaged by the body 1 only by means of an external operation made by the user, i.e. by a simple manual action.
• the external shell surface of the clamping ring 2 at the ring end intended for the elastic interaction with the ring nut 4 has a wedge-shaped or conical surface 102 that, during the step screwing the ring nut 4, just cooperates with an inner conical surface portion 104 of the ring nut 4.
• Fig.2 shows the joint in its tightened condition.
• the inner diameter of the clamping ring 2 is smaller than the outer diameter of the pipe 5 so said teeth 6 grip the outer surface of said pipe 5 allowing the ring 2 to firmly clamp said pipe 5 in the joint.
• the clamping ring 2 In addition to the fact of being elastically deformed narrowing its inner port, the clamping ring 2, contemporaneously to the above mentioned action, is subjected to an axial movement towards the inside of the body 1, still due to the ring nut 4 being screwed on said body.
• the ring nut 4 As it is easy to guess, by screwing the ring nut 4 on the body 1 an axial movement of the ring nut 4 towards the body 1 occurs . Since the inner conical surface of the ring nut 4 interacts with the wedge-shaped or conical surface of the ring 2, it results that upon an axial movement of the ring nut 4 after it has been screwed on the body 1 a movement of the ring 2 occurs in the same direction.
• the annular groove 8 has a certain axial extension and the tooth 7 of the clamping ring 2 can move, during the axial movement, towards the seal, by means of a suitable conicity of the annular fitting groove 8.
• Fig.3 shows a side view relating to a preferred solution used for the clamping ring 2. As it can be easily noted it has two axial slots 9 and 10 that are opposite and open alternatively on one of the two opposite head sides .
• axial slots 9 allow the crowns of teeth 6 on the head side of the ring intended to interact with the ring nut 4 , to be tightened by a radial restriction under the narrowing action caused by ring nut 4 screwed on the body 1, while axial slots 10 on the head side opposite to the above mentioned head side, allow the ring 2 to be deformed just enough to be inserted in the body 1 and to allow the fitting tooth 7 of the ring 2 to be engaged by a snapping action in the suitable fitting groove 8 obtained on the inner surface of the body 1 and therefore to allow the ring 2 to take a shape resembling flower petals .
• Fig.4 shows a top view of the clamping ring 2 through which it is possible to see the spatial arrangement of the two axial slots 9 and 10. As it is noted, they are staggered one with respect to the other with a given constant angle.
• Fig.l and fig.5 show a detail of the clamping ring 2 which has an intrinsic elastic force for firmly maintaining a condition such that its inner diameter is slightly greater than the outer diameter of the pipe 5 so it can be inserted in the ring without any mechanical and/or excessive friction impediments even in the engaging condition of fig.l.
• peaks of teeth 6 forming the crowns of teeth of the ring 2 lie on concentric circumferences which have diameters that are progressively reduced in their value from the outermost crown of teeth 6 to the innermost one.
• Fig.6 shows a section plane/cross section of the joint according to a first embodiment, wherein particularly the position of the annular seal such as O-ring or the like 11 can be noted being inserted inside the body 1, with the joint in its not tightened condition.
• the seat of said annular seal 11 is composed of a conical narrowing characterized by a first slightly conical portion 103 and a second portion 203 being more conical with respect to the preceiding portion, which conical narrowing extends in the side opposite to the end of the joint for introducing the pipe by a third conical narrowing 303 being slightly conical and whose length is approximately equal to the size of the diameter of the longitudinal section of the seal 11. Said terminal portion 303 of the above conical narrowing, constitutes actually the seat of the annular seal 11 with the joint tightened on the pipe 5.
• the annular seal 11 in its rest condition i.e. with the joint not in its not tightened condition, has an inner diameter greater than the outer diameter of the pipe 5 and for this reason, as it is shown in figure 6, after said seal 11 has been inserted in the body 1 it is housed in the first conical narrowing portion 103 having said greater diameter and such to keep the seal in the largest radially condition and so allowing the pipe 5 not to have any mechanical and/or excessive friction impediments when it is inserted in the joint.
• Figure 7 shows the position of the annular seal 11 with the joint tightened on the pipe 5.
• Said seal in comparison with the previous fig. 6, is axially moved towards the bottom of the seat of the seal and wherein there is provided the slightly narrowed conical portion having the smallest diameter among various diameters of the seat of the seal and however it is such to determine an inner radial compression of the annular seal against the pipe.
• Said movement of the seal 11 is caused by the pushing action made by suitable pushing means which, according to a specific technical solution, are represented by the clamping ring 2 and the ring nut 4.
• the seal After said movement and forcing action, the seal is subjected to an elastic deformation radially narrowing it, so, as it can be noted in fig.7, the inner diameter of the seal 11 is smaller than the outer diameter of the pipe 5 and such condition allows said seal 11 to adhere against the outer wall of the pipe 5 thus guaranteeing the desired hydraulic sealing effect.
• the shape memory of the clamping ring 2 allows it to elastically return back to its original not stressed shape when the compression due to the ring nut 4 has been removed, since the deformation circumferentially tightening the ring 2 due to the compression of the ring nut 4 is an elastic deformation and so, it does not lead to any considerable plastic deformation i.e. permanent deformation of the ring. Therefore the ring 2 by recovering its original shape, i.e. by becoming wider, causes the final portion of said ring 2, represented by the projecting annular tooth 7 , to slide on the wall of the conical narrowing inside the body 1 thus leading the ring 2 to axially move towards the entrance of the joint.
• the ring 2 is not more in interaction with the seal 11 that can elastically return back to its initial position inside the body 1 , i.e. on the side of the conical narrowing having the greatest diameter.
• Such movement can occur either spontaneously or at least partially by means of the pipe 5 being drawn when it is taken out from the joint and said movement is made easier by the slight conicity of the portion 303 i.e. of the sealing seat.
• FIGs 11 to 16 show a variant embodiment wherein according to a first advantageous characteristic, said coupling union 101 has an inner radial narrowing 401 composed of two opposed conical surfaces 501, 601. One of which substantially arising from the annular, radial shoulder 301 towards the opposite end of the coupling union 101 that is in the withdrawing direction of the pipe 5, and which conical surface 601 converges towards the inside of the pipe, and at the narrowing 401 it is connected to a conical surface 501 diverging towards the end of the coupling union faced in the direction for withdrawing the pipe 5 from the joint.
• the clamping ring 2 and the tightening ring nut 4 cooperate one with the other by means of mutually interaction conical surfaces provided at inner and outer head ends of the ring nut 4 and clamping ring 2 respectively, which head ends are at the opposite side of said two parts with respect to the coupling union 101.
• the clamping ring has two subsequent conical surface portions denoted by 102, 102', which have a different conicity and are connected by a rounded or beveled arcuate portion 202.
• the first conical surface end portion has a greater inclination than the one of the second conical surface portion.
• inclination refers to the angle between an axial straight line tangent to the conical surface and the pipe axis, of the ring nut 4 and/or of the clamping ring 2.
• Such term substantially is like the term conicity which in this document refers to the opening angle of the cone.
• the inner conical surface of the ring nut 4 is also composed of a first and a second portion denoted by 104 and 104' and which inner conical surface portions of the ring nut 4 like conical surface portions of the clamping ring 2 have two different inclinations and particularly the first end portion 104 has a greater inclination than the second conical surface portion 104' being less inclined.
• first conical surface portions 102 and 104 of the clamping ring 2 and of the tightening ring nut 4 respectively are abrupter than second conical surface portions 102' and 104' of corresponding parts, i.e. of the clamping ring 2 and of the tightening ring nut 4.
• the second conical surface portions 102' and 104' of the clamping ring and of the tightening ring nut 4 have the same inclination, for example 30°, and are intended for sliding one upon the other when the tightening ring nut 4 is screwed for being tightened on the coupling union 101 and against the clamping ring 2.
• the first two portions 102 and 104 on the contrary are more inclined, for example 50°.
• the first conical surface portion 102 of the clamping ring 2 has a greater inclination than the corresponding first conical surface portion 104 of the tightening ring nut 4.
• the arcuate or beveled portion 202 connecting the first and second conical surface portion 102 and 102' allows a passage free from resistances of above mentioned operating conditions to be provided, since during the passage between the two conicities the arcuate portion causes the clamping ring to have always only one tangent point against the profile of the angle area between the two conical surface portions 104 and 104' of the ring nut. Therefore a passage without resistence peaks occurs.
• the first conical surface portion of the ring nut and/or of the clamping ring has an inclination with respect to the central axis of the pipe and/or tightening ring nut and/or clamping ring greater than 30° and lower than 80°, and preferably it is from 40° to 60°, particularly from 45° to 50°.
• the second conical surface portion of the ring nut 4 and of the clamping ring 2 it has an inclination lower than 40°, preferably lower than 30° and particularly from 10° to 30°.
• the shown pipe joint is of the type wherein, the pipe can be inserted and withdrawn from the joint with the seal , clamping ring 2 tightening ring nut 4 assembled on and/or into the coupling union 101.
• the clamping ring 2 and the O-ring seal 11 have such an inner diameter that the pipe can slide into said parts with a frictional resistence against sliding that can be overcome by a manually applied force and without any excessive effort and without mechanically damaging the pipe and/or said two parts 2 and 11.
• inner conical surfaces 104, 104' of the ring nut abut against outer surfaces of the clamping ring 2 and act for circumferentially pressing the clamping ring.
• seal 11 it can be provided with such a diameter that even with the ring nut partially screwed it has an inner diameter shorter than the pipe diameter to such an extent that the head side of the pipe upon introduction into the coupling union 101 elastically expands the seal 11 which is prevented from sliding in the introduction direction by the annular shoulder. In the withdrawing direction the seal 11 is prevented from sliding by the head wall of the clamping ring 2 denoted by 302.
• the inner diameter of the seal can be such that it is shorter than the outer diameter of the pipe for an amount lower than or similar to 1 to 2,4 mm, in proportion to the size of the joint and to the chord of the O-ring.
• the groove housing the seal 11 is composed of a radial portion wider than the area with shortest diameter of the coupling union 101 from 0,1 to 0,5 mm, particularly 0,2 mm to 0,4 mm, in proportion to the size of the joint and the chord of the 0-ring.
• the latter expands the seal 11 and passes therein by a certain friction that due to said differences between the inner diameter of the seal and the outer diameter of the pipe is adjusted such that the friction of the pipe sliding inside the seal can be overcome by means of a manual force applied by a user and without using tools, at least considering a predetermined diameter range of the pipe.
• Fig. 8 shows a section plane/cross section of the joint 1 having inside the body 1 a lip seal 12, with the joint 1 in its not tightened condition and with the pipe 5 (shown by the broken line) not inserted in said joint.
• the lip seal 12 is composed of a base ring 13 having an inner diameter slightly greater than the outer diameter of the pipe and of an extension/lip 14, secured to an end of the inner surface of the base ring 13 in which the inner port delimited by said lip, has an inner diameter smaller than the outer diameter of the pipe .
• the section of said lip seal 12 or better to say the section of the base ring 13 of said seal 12 resembles to a right-angled trapezium whose oblique side has such an inclination to be complementary to the inclination of the annular abutting shoulder, which with the inner cylindrical wall of the body 1 constitutes the seat of said seal
• Fig. 9 shows a section plane/cross section of the joint 1 having inside the body 1 a lip seal 12, with the joint 1 in its not tightened condition and with the pipe 5 inserted in said joint.
• the lip 14 of the seal 12 cooperates with the outer surface of the pipe 5 when it is introduced in the joint but only by a slipping action by the inner surface 15 of said lip 14 without preventing to easily take out the sealing body, therefore even by using lip seals of the type described hereinbefore, the pipe can be freely introduced in the joint without any mechanical and/or excessive frition impediments .
• the outer surface 16 of the lip 14 comes to overlap the inner surface of the base ring 13 thus arising a space 17 having a wedge- shaped cross section.
• Fig. 10 shows a section plane/cross section of the joint 1 having a lip seal 12 inside the body 1, with the joint tightened on the pipe 5.
• the clamping ring 2 such as previously described, not only is circumferentially tightened against the outer wall of the pipe 5 according to the arrow F, but it is also subjected to an axial movement towards the inside of the body 1 and such movement causes said clamping ring together with the ring nut to act as a pushing means against the annular lip seal 12. Due to said axial movement of the clamping ring 2 , the seal 12 is pushed against the annular abutting shoulder and following said pushing action the seal 12 is circumeferentially widened.
• the annular abutting shoulder being slightly inclined, a kind of compression of seal 12 occurs therefore it results that the base ring 13 of said seal 12 is subejcted to the deformation, and such deformation results in the inner surface of the base ring to be circumferentially widened. After said circumferential widening, the inner surface of the base ring 13 pushes against the outer surface 16 of the lip 14 pushing/forcing the inner surface 15 of the lip 14 to tightly adhere against the outer surface of the pipe 5.
• the operating condition of the joint i.e.
• the circular space 17 having a wedge-shaped section is flooded by the fluid which exters a pressure on the outer surface 16 of the lip 14 , which pressure pushes the inner surface 15 of said lip 14 towards the outer surface of the pipe 5 thus cooperating with the pushing action of the base ring 13 following the elastic deformation thereof.
• the pushing action of the fluid against the outer surface 16 of the lip 14 of the seal 12 is substantially directly proportional to the pressure of the fluid inside the pipe, so by increasing the pressure, as a consequence the hudraulic sealing effect of the seal 12 increases .
• the clamping ring 2 spontaneously recovers its original position, such as shown in fig.9 and consequently, the lip seal can elastically recover its initial/original shape under not stressed conditions, either in a spontaneous way or also at least partially by the pipe being drawn when it is taken out from the joint.
• the invention allows to leave the joint in its ready condition to insert the pipe, with the seal housed in the seat and with the pipe freely moving inside it; the clamping ring already fitted in its seat and in its opened condition like a flower allowing the pipe to freely slide inside it and with the ring nut screwed on the body of the joint with the conical face abutting against the conical face of the clamping ring at the beginning of the predetermined screwing travel necessary for mechanically clamping the pipe and the desired hydraulic tight seal . Therefore the user has only to insert the pipe in the joint and so to tighten the joint by a simple rotation of the ring nut that is of minimum extent and that can be indicated by a reference between the body and the ring nut.
• the invention provides a radial projection 701 or two or more radial projections in the trajectory at one peak of a thread 201 of the coupling union 101 arising from said area in the trajectory of the peak of said thread 201 and which projection or projections are engaged into a corresponding notch or recess or in a crown of notches or recesses 204 provided at the head side of the tightening ring nut 4 faced towards the coupling union 101 that is in the front with reference to the direction for introducing the pipe 5 into the joint or screwing said tightening ring nut 4.
• Said notches or recesses 204 are open both at the head side and at the inner surface of said end of the tightening ring nut 4.
• Radial projections 701 at the bottom of the thread 201 can be elastically deformed and have such a protrusion to project with a slight interaction inside grooves 304 between threads 404 of the tightening ring nut 4, and to project more beyond the radial inner edge 504 of front recesses 204.
• interactions between projections 701 and front recesses 204 occur causing the ring nut 4 to move forward by steps which can be easily manually overcome, by holding it in the partial screwing position with respect to the coupling union 101.
• projections 701 are elastically deformed and come out from front recesses 204 passing inside the groove 304 of the thread where there is some friction obtained by the slight interaction between the projection or projections 701 and the groove 201 preventing the ring nut from freely rotating holding its predetermined preassembly position.
• the action provides to temporary hold the ring nut in a predetermined screwing position.
• the thread 201 on the coupling union 101 is provided in an axial position of said coupling union 101 corresponding to a partial screwing position of the tightening ring nut 4 wherein the clamping ring 2 and the seal 11 allow the pipe to be inserted and/or in case withdrawn by sliding inside the clamping ring 2 and the seal 11. So the tightening ring nut 4 is temporary effectively retained in its starting position which can be overcome by a simple manual effort.
• the tightening ring nut 4 and the clamping ring 2 manufactured with two conical portions denoted by 102, 102' and 104', 104' respectively cause the choice of the readiness position with the ring nut temporary retained in the partial screwing position (preassembly) on the coupling union 101 to be such that the rotation necessary to completely tighten the ring nut 4 in order to sealingly clamp the joint on the pipe is very small, approximately from half a turn to one complete turn of the ring nut, so the joint is tightened on the pipe by a very light effort and by a very simple and quick movement.
• limit stop means for the screwing tightening travel of tightening ring nut 4 on the pipe preventing also the tightening ring nut 4 from being unintentionally rotated.
• Said means advantageously are composed of a radial tooth 801 or two radial teeth or a crown of more radial teeth.
• Such radial tooth or teeth 801 are provided on the coupling union 101 in an axial position with respect to the axial position of the tightening ring nut 4 being screwed on said coupling union 101 corresponding to the joint being completely tightened on the pipe 5 , so when the ring nut reaches said axial position the radial tooth or teeth of the ring nut 204 engage into corresponding front recess or recesses 204 of the tightening ring nut 4.
• This can be obtained by means of the elasticity of radial teeth 801 that can be also the intrinsic elasticity of the material itself.
• the radial tooth or teeth 801 are composed of radial axially oriented ribs having such a circumferential thickness which thickness is lower than the corresponding size of front recess or recesses 204 of the ring nut.
• the limit stop for the introduction of the pipe denoted by 901 in figures can be omitted and the body 1 of the joint can have an inner diameter that is always slightly greater than the pipe diameter. So together with the characteristic for introducing and withdrawing the pipe into the joint without too much friction a repair joint can be obtained that is a joint particularly suitable for making repairs .
• the longer joint body 1 free from inner annular abutment shoulder 901 of the pipe allows the joint to slide inside the pipe to be repaired, without the need of disassembling ring nuts and clamping rings from the body 1 and so making repair actions considerably more easier.

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• 2008
  • 2008-02-27 AU AU2008220767A patent/AU2008220767B2/en active Active
  • 2008-02-27 WO PCT/EP2008/052366 patent/WO2008104561A2/en active Application Filing
  • 2008-02-27 EP EP08717174A patent/EP2126443A1/de not_active Withdrawn
  • 2008-02-27 WO PCT/EP2008/052367 patent/WO2008104562A1/en active Application Filing

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