HK1205232B - Threadless pipe coupling - Google Patents

Description

Threadless pipe coupling

Technical Field

The present invention relates to a threadless pipe coupling comprising: a socket; a plug configured for insertion into the receptacle in an insertion direction; a sealing member arranged between a circumferential outer surface of the plug and a mating inner surface of a circumferential side wall of the socket to provide a fluid tight seal when the plug is placed in the socket, the sealing member comprising a first sealing surface oriented in the same direction as the insertion direction and an oppositely placed second sealing surface, wherein the plug is retained in the socket by means of a locking member inserted in a transverse direction through a slot in the circumferential side wall of the socket to engage around the plug in a position closest to the second sealing surface, and when seen in a radial direction an end of the locking member is positioned in an installation position between the outer surface of the plug and the circumferential side wall of the socket, the locking member comprising a first axial end face and a second axial end face placed opposite the first axial end face, and the notch is bounded by an axial contact surface.

Within the scope of the present application, fluid may relate to liquid (in particular water), as well as to gas. In particular, the threadless pipe coupling of the present invention is configured for use in constructing and operating a pipeline and/or distribution network for oil, water and/or gas supply.

Background

Known pipe couplings, in particular in the field of oil, water and gas supply, are usually threaded couplings, or couplings which require fastening of threaded fasteners in flanges, which takes time to make the connection.

Furthermore, such threaded couplings are generally made of metal, steel, and in particular cast iron, because of the ease of production and the well-known strength of these materials. However, it is difficult to prevent corrosion of the surfaces of the threads of such connections, for example by means of a protective coating, because such protection may affect the function of the threads or because the protection will be damaged during assembly of the pipe coupling. As a result, the reliability of the coupling device is affected, particularly when used in harsh environments, such as underground use or when otherwise exposed to corrosive environments. Another drawback of such a threaded coupling is that it may sometimes be difficult to control the positioning of the connected components in terms of rotation about the axial direction, for example when installing the valve in a line and/or when it is desired to branch off a tap from the main supply line in any direction.

US 5,607,192 and GB768,974 disclose a pipe connection as described in the introduction. A disadvantage of such a coupling device is that under axial load there is a risk that the locking member will disengage from the recess in which it is placed. This is due to the configuration of the engagement surface between the locking member and the recess.

US 4,269,436 and GB827,247 disclose a tube connection structure in which locking is achieved by inserting a flexible element through an aperture. A drawback of this solution is that the coupling and locking by inserting the flexible element constitutes a cumbersome process.

Disclosure of Invention

It is therefore an object of the present invention to provide a quick coupling device which is both simple to connect and at the same time provides a safe and reliable coupling device for use in a supply line/network.

According to an aspect of the invention, there is provided an unthreaded pipe coupling as described in the introduction, with the axial end faces converging outwardly in the radial direction and the axial contact faces converging outwardly in the radial direction.

The pipe coupling of the invention is plug-in, in which a male plug is introduced into a female socket in an insertion direction and is fixed by inserting a locking device in a direction transverse to the insertion/separation direction, so as to prevent separation in a separation direction opposite to the insertion direction. Thus, in the context of the present application, the terms "axial" and "transverse" are defined with respect to the direction of insertion/separation, wherein the axial direction is defined parallel to the direction of insertion/separation, and wherein the transverse direction is defined perpendicular to the axial direction.

The sealing means ensures a sealed (i.e. fluid tight) connection, forming a fluid passage through the plug and the socket. Typically, the main axis of the fluid channel formed by the pipe coupling is also parallel to the axial direction. Preferably, the sealing means is a sealing member, such as an O-ring or a sealing member having any other known suitable sealing profile. The coupling device comprises a retaining device for retaining the plug in sealing engagement with the socket.

For connecting the coupling device, the plug is inserted into the socket in the insertion direction. When the plug is placed in the socket, the sealing means (preferably an elastic sealing member) forms a fluid tight seal between the circumferential outer wall of the plug and the inner surface of the receiving cavity formed by the circumferential side wall of the socket. The receptacle has a slot provided in the circumferential side wall through which the locking member is inserted when the plug is placed in the receptacle. Axial tensile forces may arise as a result of external forces acting on the pipe coupling from the outside and/or as a result of fluid overpressure acting on the pipe coupling from the inside compared to the surroundings. The axial tensile force acting on the pipe coupling urges the plug in a direction out of the socket (i.e., in a direction opposite to the insertion direction). Axial compression forces may occur due to, for example, a negative pressure/vacuum within the tube compared to the ambient environment. The axial compressive force acting on the tube coupling urges the plug in a direction toward the inside of the receptacle (i.e., in the same direction as the insertion direction). The locking member interacts with the plug and receptacle to withstand any axial tensile forces attempting to remove the plug from the receptacle and preferably also to withstand any axial compressive forces attempting to move the plug into the receptacle beyond a predetermined insertion depth of a desired insertion location.

Under axial load, the inclined mating axial surfaces interact to produce a radially inwardly directed force on the locking member to retain the locking member in the engaged position.

In case the surfaces are not plane but more or less rounded, it should be understood that the tangents of the surfaces in question define the direction of convergence.

As seen in the insertion direction, the locking member is arranged behind the sealing joint formed by the sealing means. The sealing of the pipe coupling is thus independent of the means for securing the plug to the mechanical connection of the socket. The locking member engages around the plug. To this end, the locking member preferably encloses more than half of the peripheral contour of the plug and preferably also interacts with the plug to provide a retaining/locking effect relative to the socket along more than half of the peripheral contour. Thus, the retention strength of the coupling against axial forces is improved, in particular against tensile axial forces acting in opposite directions on the plug and the socket, and also against compressive forces.

In one embodiment, the plug may be formed as a simple circumferential edge on the tube end to hold the sealing means in place before the edge (i.e. between the tube end and the edge), wherein the edge simultaneously provides an axial abutment surface for holding the plug in the mating socket with the aid of a locking member placed behind the edge (i.e. on the opposite side of the edge to the sealing member).

By inserting the plug into the socket and subsequently locking the position of the plug by inserting the locking member through the slot in the circumferential side wall of the socket, the threadless pipe coupling can be assembled quickly and easily without the need for any tools. Threadless pipe couplings can also be quickly and easily disassembled by simply removing the locking member and pulling the plug and socket apart. However, in order to avoid accidental disengagement of the pipe coupling, it is important to avoid any accidental disengagement of the locking member. Thus, as seen in the radial direction, the end of the locking member in the mounted/inserted position is positioned between the outer surface of the plug and the circumferential side wall of the socket and is thus hidden from the outside. Thus, the end of the locking member is protected from any interference from external influences which may damage the locking member or cause the locking member to be unintentionally disengaged from its engagement with the plug or even unintentionally push the locking member completely out of the pipe coupling, resulting in an unintentional separation of the pipe coupling and, as a result, in a severe leakage of, for example, water or gas.

Further, according to an embodiment of the threadless pipe coupling according to the invention, at least one axial end face is inclined and the other axial end face is perpendicular to the longitudinal axis of the pipe coupling and the axial contact surfaces, and each axial contact surface is directed towards an axial end face and is formed with an equivalent angled surface.

Further, according to an embodiment of the threadless pipe coupling according to the invention, both axial end faces are inclined and converge outwardly at the same angle, and the axial contact surfaces have equivalently formed angled surfaces.

Thus, the assembly between the two parts is improved.

Further, according to an embodiment of the threadless pipe coupling according to the invention, the minimum distance between the converging axial contact surfaces is d1 and the maximum distance between the axial end faces is substantially d 1.

Thus, the locking member is fitted into the notch. For improved safety, the minimum distance between the axial contact surfaces is placed furthest away from the central axis, while the maximum distance between the axial end surfaces is placed closest to the central axis.

Further, according to an embodiment of the threadless pipe coupling according to the invention, the at least one axial contact surface is provided with a circumferential recess provided in an area closest to a centre axis of the pipe coupling, and the facing axial end surfaces are provided with circumferential shoulders adapted to engage the recess when the locking member is placed in the slot.

Thus, the fastening of the locking device is improved.

Further, according to an embodiment of the threadless pipe coupling according to the invention, a first axial end surface of the locking member cooperates with an axial abutment surface provided on the plug, and a second axial end surface of the locking member, opposite to the first end surface, cooperates with an axial contact surface provided on the socket for taking up tensile axial forces pulling the plug and the socket away from each other.

This retaining effect is obtained by the locking member interacting in axial direction with both the plug and the socket via the mating bearing surfaces. These mating bearing surfaces are formed by the axial end face of the locking member and one or more mating axial abutment surfaces on the plug, together with one or more mating axial contact surfaces provided on the socket. The bearing surface is subjected to a force in the axial direction in order to hold the plug in its inserted position in sealing engagement with the socket and to provide at least a pulling lug for a sealing connection. The first and second end surfaces of the locking member are oriented in opposite directions. Thus, the axial end face of the locking member interacts with at least one axial abutment surface provided on the plug, and the at least one axial contact surface on the socket is oppositely oriented with respect to the corresponding axial abutment surface of the plug.

When the pipe coupling is assembled, the abutment surface of the plug and the corresponding contact surface of the socket face each other to enclose the locking member. When viewed in the plug-in direction, the axial abutment surface of the plug is positioned in front of the locking element and the corresponding axial contact surface of the socket is positioned behind the locking element. The tensile force pulls the axial abutment surface of the plug towards the mating first end surface of the locking element, which transmits said force via the second end surface to the corresponding axial contact surface of the socket. Thus, the plug and the socket exert oppositely directed forces on the locking member in the axial direction. Thus, the locking member bears the tensile force acting on the pipe coupling. Thus, the socket is retained in the plug, preventing the pipe coupling from separating due to axial tensile forces.

Advantageously, the plug and the socket may further comprise a secondary axial abutment surface and a contact surface, respectively. The secondary axial abutment surfaces of the plug and the secondary axial contact surfaces of the socket interact with the first and second end faces of the locking member to bear compressive axial forces acting on the pipe coupling for urging the plug towards the socket in the insertion direction.

Further, the secondary axial abutment surfaces of the plug and the corresponding secondary axial contact surfaces of the socket are oriented towards each other to enclose the locking member. However, when viewed in the insertion direction, the secondary axial abutment surface of the plug is positioned behind the locking member and the secondary axial contact surface of the socket is positioned in front of the locking member. The insertion depth of the plug is thus defined by the interaction of the minor abutment surfaces and the contact surfaces with the locking member. In combination with the above-mentioned retaining effect of the main abutment surfaces and the contact surfaces, the locking member may thus restrict or even lock the axial position of the plug in the socket.

Advantageously, the abutment surface of the plug may be formed by a circumferential groove in the outer surface of the plug and/or one or more circumferential ribs/edges/flanges provided on the outer surface of the plug. The axial contact surface of the socket may be formed by an axially oriented face of the locking element insertion slot and/or by a groove/edge/flange on the inner side of the circumferential side wall of the socket.

Further, according to an embodiment of the threadless pipe coupling according to the invention, the locking member is horseshoe-shaped with a first leg and a second leg, the distal ends of the first leg and the second leg being separated by a gap, and their proximal ends opposite the distal ends being connected to each other by a bridge. The legs of the horseshoe-shaped locking member are configured to engage around the plug to hold the locking member in place. The horseshoe-shaped clearance opening defined by the distal ends of the legs is concealed within the socket between the circumferential outer surface of the plug and the circumferential side wall of the socket. Thus, the risk of unintentionally disturbing the distal end of the locking member is avoided and unintentional separation of the threadless pipe coupling is avoided.

In a preferred embodiment, the gap width of the locking member is smaller than the outer diameter at the waist of the plug where the locking member is to be placed. Thus, the locking member is further secured against unintentional release from its insertion position. After insertion of the locking member through the insertion slot of the receptacle, the distal end of the locking element is in contact with the outer surface of the plug. Advantageously, the distal end of the locking member is suitably shaped so as to facilitate the spreading apart of the legs of the locking member when the locking member is pushed further into the slot in the transverse direction and onto the outer surface of the plug at which the distal ends of the legs first come into contact. This is achieved by the shape converting the transversely applied force into a radially outwardly directed force acting on the legs of the locking member when the legs of the locking member first contact and slide over the surface of the plug to eventually snap into place between the peripheral wall of the receptacle opposite the slot and the outer surface of the plug. For example, the surface of the distal end may be configured to be tangential to the outer surface of the plug at first contact during insertion, and may also be rounded so as to maintain more or less tangential contact as the distal end of the locking element slides over the outer surface of the plug. Further advantageously, the friction between the locking member and the plug during insertion may be reduced by a suitable choice of the material for the surface and/or by applying a lubricant.

Further, according to an embodiment of the threadless pipe coupling, the locking member is a spring clip configured to engage around the plug by a snap fit. The snap-fit engagement ensures that the laterally inserted locking member can be automatically held in place in its inserted position, allowing a reliably sealed fluid connection to be formed very quickly by means of a threadless pipe coupling.

According to an embodiment of the threadless pipe coupling, the locking member is a spring clip configured to engage around the plug by a snap-fit.

Further, according to an embodiment of the threadless pipe coupling, the locking member in the inserted position does not extend outside the protruding profile of the surface of the socket, as seen in a projection in the axial direction. Thus, the risk of the locking means being unintentionally released due to interference from external influences is further reduced. As explained in further detail below, a gripping device may be provided on the locking device in order to facilitate removal of the locking device for disassembling the coupling device.

Further, according to an embodiment of the threadless pipe coupling, at least one of the axial end surfaces of the locking member and the mating abutment surface of the plug and/or the mating contact surface of the socket are perpendicular to the axial direction and parallel to each other.

The pairs of cooperating bearing surfaces, which are oriented perpendicular to the axial direction and parallel to each other, transmit/receive axial forces acting also in the axial direction on the pipe coupling. By providing such an axial bearing surface, the generation of radial components, and in particular radially outwardly directed force components acting on the locking member, which components may otherwise lead to an unintentional ejection of the locking member from its insertion position when an axial load is applied to the pipe coupling device, is avoided.

Thus, a first axial end surface of the locking member perpendicular to the axial direction may cooperate with a parallel axial abutment surface of the plug to form a pair of axial bearing surfaces. Accordingly, a second axial end surface of the locking member perpendicular to the axial direction may cooperate with a parallel axial contact surface of the plug to form another pair of axial bearing surfaces.

Further, according to an embodiment of the threadless pipe coupling, at least one of the axial end surfaces of the locking member is convexly tapered, and the mating abutment surface on the plug and/or the mating contact surface of the socket is concavely tapered, so as to press the locking member radially inwards when the mating surfaces are pressed towards each other due to an axial load applied to the pipe coupling. By providing a concave tapered surface on the plug and/or the socket (wherein the mating first and/or second end faces of the locking member are convexly tapered), an axial load applied to the pipe coupling device generates a radially inwardly directed force component acting on the locking member, thereby holding the locking member in the inserted position. The axial load may be a tensile axial force pulling the plug out of the socket in a separating direction opposite to the plug-in direction, and/or a compressive axial force pushing the plug into the socket in the plug-in direction. The term "concave taper" refers to a tapered surface in which the normal vector of the surface points inwardly toward the central axis of the pipe coupling. Accordingly, the term "convex taper" refers to a tapered surface in which the normal vector of the surface points outwardly (i.e., away from the central axis of the pipe coupling).

According to an embodiment of the threadless pipe coupling, at least one of the axial end surfaces of the locking member is convexly tapered, and the mating abutment surface on the plug and/or the mating contact surface of the socket is concavely tapered, so as to press the locking member radially inwards when the mating surfaces are pressed towards each other due to an axial load applied to the pipe coupling.

Further, according to an embodiment of the threadless pipe coupling, the locking member is provided with an extension flap, which is hinged to the distal ends of the first and second legs. The extending tabs allow to increase the effective engagement surface of the locking element and to increase the friction of the peripheral profile involved in the retention/locking interaction between the locking element and the plug/socket. The extension flap is configured to extend into the gap between the distal ends of the legs of the horseshoe-shaped locking element in order to close or at least reduce said gap. Preferably, the locking element with the extending tabs surrounds the circumference of the plug, thereby providing a retention/locking effect that is evenly distributed around the circumference of the pipe coupling.

According to an embodiment of the threadless pipe coupling, the locking member is provided with an extension flap, which is hinged to the distal ends of the first and second legs.

Further, according to an embodiment of the threadless pipe coupling, the locking member is provided with one or more gripping means thereon, wherein the gripping means are configured to grip the locking member for removing the locking member from the insertion position. The gripping means for disassembling the locking ring preferably comprises lugs and/or recesses configured to allow finger engagement of the locking member, thereby allowing the locking member to be removed by hand without the need for additional tools. Alternatively or additionally, the gripping means may comprise recesses and/or protrusions configured to engage with a corresponding gripping tool. The gripping means is to be arranged in a position on the locking member which is accessible from the outside of the socket when the locking member is in its insertion position. For example, since the distal end in the insertion position is hidden within the circumferential wall of the socket, the gripping means provided at the distal end are not suitable for the purpose of removing the locking member from its insertion position.

According to an embodiment of the threadless pipe coupling, the locking member is provided with one or more gripping means for gripping the locking member in order to remove the locking member from the insertion position.

Advantageously, a protective flange/rim is provided on the socket around any protruding gripping means in order to provide a protruding contour of the outer surface of the socket, as seen in axial projection, said protruding contour encompassing the locking means. Thus, unintentional release of the locking device due to interference with larger tools (such as digging tools in underground installations) is avoided, making it easier to intentionally remove the locking device from the insertion position using a finger, a small hand tool, or a special gripping tool.

Furthermore, according to an embodiment of the threadless pipe coupling, the pipe coupling comprises a plurality of locking members. Preferably, each locking member interacts with a respective mating axial abutment surface on the plug and a respective mating contact surface on the socket. By using a plurality of locking members, the retention and/or locking of the plug in the socket is improved. By providing redundancy with additional locking elements, the safety of the pipe coupling is enhanced.

According to an embodiment of the threadless pipe coupling, the pipe coupling comprises a plurality of locking members.

Furthermore, according to an embodiment of the threadless pipe coupling, the sealing member is pre-mounted on the outer surface of the plug. Preferably, the sealing member is held in place by a circumferential groove in the outer surface of the plug and/or by one or more radially outwardly projecting lugs on the outer surface of the plug. The pre-installation of the sealing means avoids the need to handle the sealing means when connecting the pipe coupling. As an alternative to pre-mounting the sealing device on the plug, the sealing device may be pre-mounted in the socket. However, pre-installation on a plug is somewhat easier to handle at the time of production, or at the time of replacement or inspection of the seal (e.g., during maintenance work).

According to one embodiment of the threadless pipe coupling, the sealing member is pre-mounted on the outer surface of the plug.

Advantageously, the peripheral side wall of the socket comprises two cavities with different internal diameters located in the receiving cavity formed by the peripheral side wall. In the outer chamber adjacent the receiving opening of the receptacle, the inner diameter reaches or exceeds the outer diameter of the plug, with an uncompressed resilient sealing means (such as an O-ring) mounted on the outer surface of the plug. In the inner chamber, in which the sealing joint is to be formed, the value of the inner diameter is smaller than the sealing means in the uncompressed state, as is required for achieving a fluid-tight connection. A transition region is provided between the outer and inner chambers where the inner diameter of the receiving cavity of the socket gradually/smoothly decreases from the inner diameter of the outer chamber to the inner diameter of the inner chamber. Preferably, the cross-section of the inner chamber, the outer chamber and the transition region is circular, as seen in a transverse section perpendicular to the axial direction. Thus, insertion of the plug into the socket is simplified, and where applicable also compression of any resilient sealing means pre-mounted on the plug, and the risk of damage to the sealing means during insertion is reduced. It is further advantageous if a slot for insertion of the locking device is provided in the outer region of the socket. Thus, the risk of damage to the sealing means during insertion is further reduced.

Further, according to an embodiment of the threadless pipe coupling, the pipe coupling comprises a plurality of sealing members, thereby improving the sealing. Furthermore, the redundancy of the additional sealing means increases the reliability of the sealing of the pipe coupling.

According to an embodiment of the threadless pipe coupling, the pipe coupling comprises a plurality of sealing members.

Furthermore, according to an embodiment of the threadless pipe coupling, the pipe coupling further comprises radial guiding/centering means and/or axial supporting means in order to reduce any slack of the pipe coupling when the plug is tilted and/or inclined with respect to the socket. Thus, the reliability of the seal and the reliability of the mechanical connection provided by the pipe coupling is enhanced.

According to an embodiment of the threadless pipe coupling, the pipe coupling further comprises radial guiding/centering means and/or axial support means in order to reduce any slack of the pipe coupling when the plug is tilted and/or inclined with respect to the socket.

Advantageously, the radial guiding/centering means may comprise one or more centering rings arranged behind the sealing means and/or further advantageously behind the locking means. The centering ring may be conically tapered in order to wedge the plug into a centered position in the socket and avoid tilting/skewing of the plug relative to the socket. Advantageously, the axial support means may comprise an axial bearing surface on the plug which cooperates with a corresponding axial bearing surface on the socket to prevent tilting/skewing of the plug relative to the socket. Any combination of a plurality of radial centring means and/or a plurality of axial bearing means and/or one or more centring means with one or more axial support means will further act to mitigate undue deformation of the sealing means due to tilting or skewing of the plug relative to the socket, thereby avoiding any risk of seal failure.

Advantageously, according to one embodiment, the plug and/or the socket are made of cast iron encapsulated with a corrosion protective coating. Preferably, the corrosion protection coating is a powder coating, such as an epoxy powder coating. Alternatively, the plug and/or receptacle may also be made of other materials suitable for underground operations and corrosive environments, such as plastic materials, corrosion-resistant metal alloys, or corrosion-protective metal alloys.

Advantageously, according to one embodiment, the locking member is made of a plastic material, such as POM. The material selected for the locking member should generally be stiff with respect to compression in the axial direction, but provide sufficient resilience in the radial direction to allow lateral insertion of the locking member around the plug, preferably so that the locking member engages around the plug by a spring-resilient snap action. An example of a plastic material that meets these conditions is Polyoxymethylene (POM), which is a relatively hard, resilient material, suitable for providing a spring action, and which meets the requirements of avoiding damage to, for example, the epoxy powder coating of the plug and/or socket. Other suitable plastic materials may include thermoplastic materials suitable for production by injection molding, as long as sufficient stiffness can be provided to resist axial compression and sufficient resilience in the radial direction as required to allow insertion of the locking member in the transverse direction can be achieved. Alternatively, the locking member may also be made of a metal or metal alloy, such as a resilient steel, preferably stainless steel.

In the case of a corrosion protective coating provided on the plug and/or socket, any damage to such a coating when inserting the locking member should be avoided. Advantageously, this can be achieved by: the locking member is made of a material having a sufficiently soft surface so as not to cause scratching/damage on the surface of the plug and/or receptacle. Alternatively or additionally, the locking member should advantageously be shaped so as to avoid the formation of sharp edges on those parts, i.e. parts which come into contact with the surface of the plug and/or socket during insertion of the locking member, and preferably also when the locking member is in its inserted position.

Further, according to a preferred embodiment of the threadless pipe coupling, the circumferential outer surface of the plug and the mating inner surface of the circumferential side wall of the socket have a circular cross-section when viewed in a transverse sectional direction perpendicular to the axial/insertion direction. Thus, the threadless pipe coupling is configured to allow the plug to freely rotate relative to the receptacle about a central axis in the axial direction. This allows the rotational positioning of the plug relative to the socket to be easily adjusted at any rotational angle about a central axis (i.e. an axis of rotational symmetry which is parallel to the axial direction and comprises the respective centers of the concentrically aligned circular cross-sections of the plug and the socket).

According to an embodiment of the threadless pipe coupling, the circumferential outer surface of the plug and the mating inner surface of the circumferential sidewall of the socket have a circular cross-section.

Further, according to an embodiment of the threadless pipe coupling, the plug of the assembled pipe coupling is freely rotatable relative to the socket about a Centre Axis (CA) parallel to the axial direction.

Further, according to an embodiment of the threadless pipe coupling, stop means are provided to limit or prevent a rotation of the plug relative to the socket about a centre axis parallel to the axial direction. Although the circular cross-section of the plug and receptacle allows the plug of the connected pipe coupling to rotate freely relative to the receptacle, it may be desirable in some circumstances to: such rotation is prevented by providing a lock stop, or limited to at least a predetermined angular range by providing a limit stop. A locking stop may be useful, for example, to secure the pipe coupling against rotation when a tapping tool (tap) is used to connect the building pipe to the main supply line. A limit stop may be useful, for example, to limit the angular range of the valve relative to the orientation of the line intercepted by the valve. The predetermined limited angular range covers less than 360 degrees of rotation, for example 270 degrees of rotation, 180 degrees of rotation, 120 degrees of rotation, or 90 degrees of rotation. The stop means may be realized, for example, as one or more cooperating radial protrusions and recesses provided on the plug and the socket.

According to an embodiment of the threadless pipe coupling, stop means are provided to prevent rotation of the plug relative to the socket about a Centre Axis (CA) parallel to the axial direction.

Further, according to an embodiment, the threadless pipe coupling further comprises a protective sleeve applied around the socket, wherein the protective sleeve encapsulates the locking member in the insertion position and seals the slot of the socket. The sleeve prevents the ingress of dust, mud or fluid from the outside which may corrode or otherwise damage the pipe coupling. The protective sleeve thus protects the pipe coupling in a harsh environment. The protection sleeve further secures the locking member against accidental removal from the insertion position, thereby achieving an even more secure connection. The sleeve is particularly advantageous in embodiments where the locking element does not protrude from the surface of the receptacle.

According to an embodiment of the threadless pipe coupling, the locking member comprises a locking sleeve, wherein the locking sleeve is arranged to be inserted into the receptacle.

Advantageously, according to one embodiment, the protection sleeve is axially slidable between a first axial position, which permits access to the slot for insertion/removal of the locking member, and a second axial position, which prevents access to the slot for the locking member. Further advantageously, according to one embodiment, the protection sleeve is rotationally slidable around a peripheral surface of the socket between a first rotational position, which permits access to the slot for insertion/removal of the locking member, and a second rotational position, which prevents access to the slot for the locking member. Further advantageously, according to a preferred embodiment, the slidable protective sleeve is held in the second position by a snap-fit engagement. Advantageously, the snap fit may be provided by an edge on an inwardly facing surface of the protection sleeve, which edge engages the locking member insertion slot of the socket when entering the second axial and/or rotational position. Alternatively or additionally to the protection sleeve, the tube coupling may comprise a foil sheath enclosing at least the socket and sealing the slot of the socket. Preferably, the sheath is made of a shrink hose material configured to fit snugly around the assembled pipe-coupling. Thus, a sealed encapsulation is provided to protect the pipe coupling from external influences, such as corrosion or dust intrusion, and further to secure the locking member against accidental removal from its insertion position.

According to another aspect of the present invention, there is provided a plug for a threadless pipe coupling, wherein the plug is configured for use in a threadless pipe coupling according to any of the embodiments described above.

According to another aspect of the present invention, there is provided a socket for a threadless pipe coupling, wherein the socket is configured to be used in a threadless pipe coupling according to any of the embodiments described above.

According to another aspect of the present invention, there is provided a locking member for a threadless pipe coupling, wherein the locking member is configured to be used in the threadless pipe coupling according to any of the embodiments described above.

According to another aspect of the invention, a saddle clamp for building a tapping joint of a supply line for water or gas is characterized in that it comprises a plug for a threadless pipe coupling and/or a socket for a threadless pipe coupling, wherein the plug and socket are configured for use in a threadless pipe coupling according to any of the embodiments described above. The tap fitting of a water or gas supply line is therefore characterized in that it comprises a threadless pipe coupling according to any of the embodiments described above. Further, the saddle clamp for building a tapping joint of a supply line for water or gas is characterized in that it comprises a plug for a threadless pipe coupling and/or a socket for a threadless pipe coupling, wherein the plug and socket are configured for use in a threadless pipe coupling according to any of the embodiments described above. The use of a threadless pipe coupling according to any of the embodiments described above significantly simplifies the task of constructing and running a tap fitting. A tap fitting is used when branching a new line from an existing line (e.g. when branching a building siding from a main water or gas supply line).

Drawings

The invention is further explained below with reference to exemplary embodiments, wherein, in general, like reference numerals refer to like parts. The figures show:

figure 1 is an axial cross-sectional view of a threadless pipe coupling according to one embodiment,

figure 2 is an axial cross-sectional view of a receptacle and plug for a pipe coupling according to another embodiment,

fig. 3 is a transverse cross-sectional view of the pipe coupling of fig. 2, wherein the plug is placed in the socket and the locking element is inserted,

figure 4 is an axial cross-sectional view of the locking element of figure 3,

figure 5 is an axial cross-sectional detail of a socket according to an embodiment of the threadless pipe coupling,

fig. 5a is an axial cross-sectional detail of a socket according to an embodiment of a threadless pipe coupling, the socket comprising a recess,

figure 6 is an axial sectional detail of a locking member for the pipe coupling of figure 5,

fig. 6a is an axial cross-sectional detail of a locking member for the pipe coupling of fig. 5a, said locking member comprising a shoulder,

figure 7 is an end view of the locking element including the extension tab,

figure 8 is a different embodiment of the locking element comprising a gripping device,

figure 9 is another embodiment of the locking element,

figure 10 is a perspective view of a receptacle and corresponding locking element for a threadless pipe coupling according to another embodiment,

fig. 11 is a transverse cross-sectional view of the pipe coupling of fig. 9, with the plug placed in the socket and the locking element inserted,

fig. 12 is a partially cut away side view of a pipe coupling according to another embodiment, the pipe coupling including a protective sleeve,

fig. 13 is a side view, partially cut away, of a pipe coupling according to another embodiment, including another protective sleeve,

fig. 14 is an axial cross-sectional view of an unthreaded pipe coupling device, including a stop device,

fig. 15 is an axial cross-sectional view of an unthreaded pipe coupling device including a stop device and a radial guide/centering device, according to another embodiment, an

FIG. 16 is a perspective view of a saddle clamp tap joint including a pipe coupling according to another embodiment.

Detailed Description

With reference to fig. 1, a tap fitting for branching a side pipeline 2 from a main pipeline 1 by means of a saddle 3 may comprise a threadless pipe coupling 100. The saddle 3 may comprise a socket 101 forming a female part of the pipe coupling 101. The pipe end of the side line 2 or, as shown in the figures, the adapter part 4 (which receives the side line 2 in a sealing and clamping engagement) may be provided with a plug 102 which forms a protruding part of the pipe coupling 100, which plug is inserted into the socket 101 in the insertion direction 10, thus forming a fluid passage which is sealed by a sealing member 103 which is provided between a circumferential outer surface 104 of the plug 102 and a mating inner surface 105 of a circumferential side wall 106 of the socket 101. The sealing member 103 comprises a first sealing surface 160, which is oriented in the same direction as the insertion direction, and an oppositely arranged second sealing surface 161. When the plug 102 is placed in the socket 101, the plug 102 is held in the socket 101 by means of a locking member 107 which is inserted through a slot 108 in a circumferential side wall 106 of the socket 101 in a transverse direction perpendicular to the insertion direction 10. The locking member is horseshoe-shaped and engages around the plug 102 in a groove 109 provided on the circumferential outer surface 104 of the plug 102 and located behind the sealing member 103 when seen in the insertion direction 10, wherein an end of the locking member 107 is positioned between the outer surface 104 of the plug 102 and the circumferential side wall 106 of the socket 101 in its mounted position when seen in the radial direction. In the mounted position, the locking member 107 does not protrude outside the contour of the socket 101. Thus, the locking member 107 is protected from interference from external influences, which may lead to unintentional removal of the locking member 107 and thus to undesired detachment of the pipe coupling device 100.

The locking member 107 has a first axial end face 110 which cooperates with an axial abutment surface 111 on the plug 102 and a second axial end face 112 which is opposite the first end face 110 and which cooperates with an axial contact surface 113 on the socket 101 so as to receive an axial tensile force which pulls the plug and socket away from each other, thereby retaining the plug 102 in the socket 101. Further, the first and second axial end surfaces 110, 112 of the locking member 107 may cooperate with axial contact surfaces 114 on the receptacle 101, and axial abutment surfaces 115 on the plug 102, respectively, to prevent insertion of the plug 102 beyond a predetermined insertion depth in the receptacle 101 and to lock the plug 102 in a fixed position relative to the receptacle 101. In the embodiment shown, the axial abutment faces 111, 115 of the plug 102 are formed by axial side walls of the recess 109. The bottom of the groove 109 defines the diameter of the waist of the plug 102 at the location of the locking member 107. The axial contact surfaces of the socket may be formed by the axial side walls of the slot 108, by grooves (not shown), and by radially inwardly projecting flanges, all provided on the circumferential side wall 106 of the socket 101.

Referring to fig. 2 to 4, the pipe coupling 200 includes a socket 201 and a plug 202. The receiving cavity of the socket 201 comprises cylindrical chambers 216, 218, 219, and a conical chamber 217 connecting the cylindrical chamber 218 with the cylindrical chamber 216. The chambers 216, 217, 218, 219 are defined by the circumferential wall 206 of the socket 201. The circumferential outer surface 204 of the plug 202 has cylindrical surfaces 220, 221 that mate with the cylindrical cavities 216, 219 of the receptacle 201 for alignment when the plug 202 is placed in the receptacle 201. Specifically, cylindrical surface 220 mates with cylindrical cavity 216, and cylindrical surface 221 mates with cylindrical cavity 219. The plug 202 further comprises a radial flange 222 having an axial abutment surface 223 that directly interacts with an axial contact surface 224 on the socket 201 to define the insertion depth and prevent the inserted plug 202 from tilting relative to the socket 201. A sealing member (not shown) is preferably pre-installed on the plug 202 and held in place in a circumferential channel 225 provided at the end of the plug 202. The sealing member protrudes slightly out of the channel 225 and forms a fluid tight seal by pressing the sealing member between the bottom of the channel 225 on the circumferential outer surface 204 of the plug 202 and the inner surface of the cylindrical chamber 216 of the socket 201. To facilitate easy insertion of the plug 202 into the receptacle 201 when the sealing member is pre-installed in the passage 225 of the plug 202, the inner diameter of the cylindrical chamber 219 is greater than or equal to the outer diameter of the expanded sealing device installed in the passage 225 of the plug 202. Furthermore, the inner diameter of the cylindrical chamber 218 is larger than the outer diameter of the expanded sealing device mounted in the passage 225 of the plug 202, and the conical chamber 217 provides a smooth transition from the larger inner diameter of the cylindrical chamber 218 to the smaller diameter of the cylindrical sealing chamber 216. The transition may be, for example, conical or smoothly rounded. The plug 202 is fixed in the inserted position by a locking member 207. The locking member 207 is inserted through a semi-circular slot 208 located in the circumferential side wall 206 of the socket 201 in the region of the annular chamber 218, wherein the slot 208 is oriented transversely with respect to the axial direction indicated by the central axis CA. In its installed position, the locking member 207 engages around the plug 202 in a recess 209 which is aligned with the notch 208 when the plug 202 is correctly placed in the socket 201.

The locking member 207 is horseshoe shaped having a first leg 226 and a second leg 227, wherein distal ends 228, 229 of the first and second legs 226, 227 are separated by a gap, and their proximal ends opposite the distal ends are connected to each other by a bridge 230. The bottom of the recess 209 defines a waist of the plug 202 at the location where the locking member 207 is mounted. The locking member 207 is made of an elastic material and in its relaxed state the gap between the distal ends 228, 229 of the locking member 207 is smaller than the diameter of the plug 202 at the waist in the bottom of the recess 209. The locking member 207 is installed by: the legs 226, 227 are extended to slide around the bottom of the groove 209 by inserting the locking member 207 transversely through the slot 208 into the groove 209 with the distal ends 228, 229 leading and pushing the locking member 207 with a slight pressure applied to the pressure surface 231 on the bridge 230 until the locking member 207 snaps into place to engage around the plug 202 in the groove 209. Advantageously, the distal end of the locking member is suitably shaped so as to extend the legs of the locking member when the locking member is inserted transversely through the slot to engage around the plug. To this end, the surface of the distal end may be configured to be tangential to the outer surface of the plug (where the locking member first encounters the outer surface of the plug), and may also be rounded so as to maintain a more or less tangential contact as the distal end of the locking element slides over the outer surface of the plug during insertion.

Preferably, the locking member 207 is generally dimensioned such that it is also in its relaxed state after being mounted, relative to the diameter of the waist of the groove 209, thereby avoiding any continuous stress when connecting the pipe coupling 200 and possible failure of the material of the locking member 207. When placed in the pipe coupling 200, the locking member 207 interacts via its axial end faces 210, 212 with the side walls 211, 213, 214, 215 of the groove 209 and of the slot 208 to lock the plug 202 in place in the socket 201. The axial end faces 210, 212 of the locking member 207 and the mating axial abutment faces 211, 215 of the plug 202 and the mating contact surfaces 213, 214 of the socket 201 are planar, parallel to each other, and at least one surface is inclined with respect to the radial direction.

The pipe-coupling device 200 may be disconnected by: the locking member 207 is simply removed from the recess 209 through the slot 208 and the plug 202 is pulled out of the receptacle 201. To facilitate easy intentional removal, the locking member 207 preferably includes gripping means, such as outwardly projecting lugs 232, 233 on the legs 226, 227 for gripping and disengaging the locking member from its engaged position with two fingers. To avoid inadvertent removal of the locking device (e.g., interference due to rough handling of the tube coupling device with an excavating tool), the distal ends 228, 229 of the locking members 207 are placed between the outer surface 204 of the plug 202 and the circumferential sidewall 206 of the receptacle 201 when viewed in the radial direction. Further, the locking member 207 preferably does not protrude from the protruding profile 234 of the receptacle 201 when viewed in an end view in the axial direction.

Fig. 5 and 6 show details of an embodiment of the pipe coupling, wherein the locking member 507 has convex conical axial end surfaces 510, 512 and the socket 501 has a transverse insertion slot 508 with concave conical axial side walls 513, 514 for cooperation with the convex conical end surfaces 510, 512 of the locking member 507. Accordingly, the axial abutment surface of the respective plug (not shown) may also have a convex conical surface corresponding to the mating concave conical end surface of the locking member 507. Thus, under axial load, the inclined mating axial surfaces interact to produce a radially inwardly directed force on the locking member 507 to hold the locking member 507 in the engaged position.

The locking member comprises a first axial end face 510 and a second axial end face 512 disposed opposite the first end face 510, and the slot 508 comprises and is bounded by axial contact surfaces 513, 514. The axial end faces 510, 512 converge outwardly in the radial direction, and the axial contact surfaces 513, 514 also converge outwardly in the radial direction. The angle between the converging surfaces-the apex angle-is preferably 3-15 deg., more preferably 3-8 deg..

In this figure, both axial end faces are inclined, converge outwardly and have the same angle. The same applies to the axial contact surfaces. However, the surfaces may also be formed such that at least one axial end surface 510, 512 is inclined and the other end surface is perpendicular to the longitudinal axis of the pipe coupling. The contact surfaces directed towards the end faces are formed with equally angled surfaces.

Fig. 5a and 6a show a modified embodiment of the pipe coupling shown in fig. 5 and 6. The side walls/axial contact surfaces 513, 514 are each provided with a circumferential recess 562 which is placed closest to the centre axis. The end faces 510, 512 are provided with a circumferential shoulder 563. When locking member 507 is placed in insertion slot 508, shoulder 563 abuts recess 562 to provide a more secure locking mechanism.

The minimum distance between the converging axial contact surfaces 514, 513 is d1 and the maximum distance between the axial end faces 510, 512 is substantially d 1. Thus, the locking member may be pressed down in the notch. In addition, the fit between the two parts appears to be such that the locking member is safely placed.

Fig. 7-9 show by way of example further advantageous features of different embodiments of a locking member for a threadless pipe coupling. The horseshoe-shaped locking member 707 shown in fig. 7 includes extension tabs 750, 751 that are hinged to distal ends 728, 729 of legs 726, 727. The extension tabs 750, 751 are configured to extend into and substantially fill the gap between the distal ends 728, 729 so as to form a closed loop or at least reduce the gap when the locking member 707 is installed in any embodiment of a pipe coupling according to the present invention. The extension tabs 750, 751 do not assist in snapping the locking member 707 onto the plug, but they allow for an increase in the effective axial mating surface of the locking element and for an increase in the friction of the peripheral profile involved in the retention/locking interaction, yet allow for easy and quick insertion of the locking member 707 into the pipe coupling for full engagement around the plug. Fig. 8 shows different embodiments of the locking element, including different types of gripping means 832, 833, 835, 836, 837, 838. The different types of gripping devices 832, 833, 835, 836, 837, 838 may be used independently, or may be used in combination with one another. In addition to the lugs 832, 833 arranged at the legs of the locking element, the gripping means may also comprise a boss 835 on the top of the bridge, protrusions/noses 836, 837 on the sides of the bridge configured to be gripped by hand, and/or a recess/recess 838 provided on the outside of the locking member and configured to be gripped by a tool.

The locking member may advantageously be shaped to increase the flexibility in the radial direction while increasing the rigidity of the locking member in the axial direction. Fig. 9 shows such an embodiment of a locking member 907, which may be made of e.g. a plastic material, or of metal, such as stainless steel, wherein the shape is undulated in the circumferential/tangential direction, whereas the shape is linearly extruded in the axial direction. In addition to controlling flexibility, the wave shape also provides a gripping means.

Fig. 10 shows a perspective view of a socket 1001 with a transverse insertion slot 1008 and a corresponding locking element 1007. The slot 1008 is provided with a protective edge 1039 surrounding the slot 1008 in order to protect the locking member 1007 in its inserted position from unintentional interference from influences from the outside.

Fig. 11 shows a cross-sectional end view of a pipe coupling 1000 in the axial direction. The pipe coupling 1000 comprises a socket 1001, a plug 1002 placed in the socket 1001, and a locking member 1007 which in its inserted position engages around the plug 1002. Distal ends 1028, 1029 of locking member 1007 are positioned such that they are protected from external interference and are located between circumferential sidewall 1006 of receptacle 1001 and outer surface 1004 of plug 1002. The locking element is provided with a pressure surface 1031 comprising a boss 1035 on the top of the bridge of the locking element 1007 and lugs 1032, 1033 projecting radially outward from the legs 1026, 1027 on the sides of the locking element. When viewed in axial projection in fig. 11, the protective edge 1039 provides a protruding profile 1034 that completely surrounds the profile of the locking element 1007 in the inserted position, thereby protecting the locking element 1007 from inadvertent removal as described above.

Fig. 12 shows another embodiment 1200 of a pipe coupling comprising a socket 1201 and a plug 1202 locked together by a locking member 1207. The tube coupling 1200 further comprises a protection sleeve 1240 slidable between a first open position a on the socket 1201 in which the insertion slot 1208 of the socket 1201 is accessible, and a second closed position B in which any gap at the outer joint 1242 between the plug 1202 and the socket 1201 and the insertion slot 1208 are covered by the protection sleeve 1240. Preferably, the protective sleeve 1240 has inwardly projecting latch noses 1241 which engage the slots 1208 when the sleeve 1240 is in the closed position B. The protective sleeve may be adapted to the embodiment shown in fig. 1-6 a.

An alternative embodiment 1300 of a pipe coupling is shown in fig. 13, which comprises a protective sleeve 1340 and which may also be applied to the embodiments shown in fig. 1-6 a. The pipe coupling 1300 also has a socket 1301 and a plug 1302 locked together by a locking member 1307. The protection sleeve 1340 is slidable between a first open position a on the plug 1302 in which the insertion slot 1308 of the socket 1301 is accessible when the plug 1302 is placed in the socket 1301, and a second closed position B in which any gaps at the outer engagement 1342 between the plug 1302 and the socket 1301, as well as the insertion slot 1308, are covered by the protection sleeve 1340. Preferably, the protection sleeve 1340 also has an inwardly projecting latch nose 1341 that engages the notch 1308 when the sleeve 1340 is in the closed position B. The protection sleeves 1240, 1340 effectively prevent any dirt from entering into the locking mechanism and further into the sealing portions of the tube coupling devices 1200, 1300 and, in addition, effectively secure the locking members 1207, 1307 in their inserted position.

Fig. 14 and 15 show further embodiments 1400, 1500 of a pipe coupling, here embodied in the form of a saddle clamp tap joint for connecting a side line to a main line. The tube coupling 1400, 1500 is provided with stop means comprising protrusions 1443, 1543 on the plugs 1402, 1502 and mating recesses 1444, 1544 on the sockets 1401, 1501. The embodiment shown in fig. 15 further includes extensions 1545, 1546 on receptacle 1501 and plug 1502, respectively, and an additional guide/centering ring 1547 to prevent plug 1502 from tilting relative to receptacle 1501, as indicated by the double arrow. The socket/plug tube coupling may be integrally formed with the tube end at which it is disposed (as shown for example in the socket portions 1401, 1501 on the clamp 3), or the socket/plug tube coupling may also be provided as an adaptor which may be attached to any other component, for example by means of conventional screws, as indicated in the distal end of the plug portions 1402, 1502 of the tube couplings 1400, 1500 shown in fig. 14 and 15.

Fig. 16 shows the use of a freely rotatable embodiment of a pipe coupling 1600 for branching off a building line 2 from a horizontal main supply line 1, wherein a vertical tap joint is provided from the top using a saddle 3. The upper part of the saddle clamp 3 is provided with a socket 1601 receiving a plug 1602, which is locked to the socket 1601 by a locking element 1607. Plug 1602 is also connected to horizontal building line 2 by a 90 degree bend. Since plug 1601 is configured to freely rotate relative to receptacle 1602 about a vertically oriented central axis CA, building line 2 can be easily adjusted to point in any horizontal direction, thus significantly simplifying the installation of such building lines.

While the present invention has been discussed with respect to exemplary embodiments, alternative and equivalent variations of these embodiments will be apparent to those of ordinary skill in the art. For example, instead of using a pipe coupling in a tap fitting, the pipe coupling may also be used for making, operating and breaking any other fluid connection in a supply network, such as for connecting pipe ends to each other, for inserting a valve in a pipeline, for temporarily connecting a tap bit, etc. Also, the plug and receptacle are clearly interchangeable to replace the receptacle with a plug, and vice versa, without departing from the scope of the invention.

Reference numerals

1 main pipeline

2 side pipeline

3 saddle-shaped clamp

4 fitting

10 plug insertion direction

X0O pipe coupling device

X01 socket

X02 plug

x03 sealing member

Circumferential outer surface of x04 plug

Inner surface of circumferential sidewall of x05 socket

Circumferential side wall of x06 socket

x07 locking member

x08 transverse insertion slot

x09 circumferential groove

x10, x12 first and second axial end faces

x11, x15 axial abutment surface

x13, x14 axial contact surface

Cylindrical chamber of x16, x18, x19 socket

Tapered chamber of x17 socket

Cylindrical portion of the circumferential outer surface of an x20, x21 plug

x22 radial flange

x23 axial abutment surface

x24 axial contact surface

x25 circumferential channel

x26, x27 support leg

x28, x29 distal end

x30 bridge

x31 pressure surface

x32, x33 holding device (lug)

Projection profile of x34 socket

x35 holding device (Boss)

x36, x37 holding device (protrusion/nose/recess)

x38 holding device (concave/concave seat)

x39 protective edge

X40 protective sleeve

x41 latch lug

Outer joint between x42 plug and socket

x43, x44 stop device

x45, x46 extensions

x47 guiding/centering device

x50, x51 extension tab

x60 first sealing surface

x61 second sealing surface

x62 circumferential recess

x63 circumferential shoulder

A open position

B closed position

CA central axis.

Claims (18)

1. Threadless pipe coupling (x00) comprising: a socket (x 01); a plug (x02) configured for insertion into the socket (x01) in an insertion direction (10); a sealing member (x03) arranged between a circumferential outer surface (x04) of the plug (x02) and a mating inner surface (x05) of a circumferential side wall (x06) of the socket (x01) so as to provide a fluid tight seal when the plug (x02) is placed in the socket (x01), the sealing member (x03) comprising a first sealing surface (x60) facing the insertion direction and an oppositely facing second sealing surface (x61), wherein the plug (x02) is held in the socket (x01) by means of a locking member (x07) inserted through a slot (x08) in the circumferential side wall (x06) of the socket (x01) in a transverse direction perpendicular to the insertion direction to engage around the plug (x02) at a position closest to the second sealing surface (x61), when seen in a radial direction, a distal end (x28, x29) of the locking member (x07) is positioned in an installed position between an outer surface (x04) of the plug (x02) and the circumferential side wall (x06) of the socket (x01), the locking member comprising a first axial end surface (x10) and a second axial end surface (x12) placed opposite to the first axial end surface (x10), and the slot being defined by axial contact surfaces (x13, x14), characterized in that the axial end surfaces (x10, x12) are convexly tapered and the axial contact surfaces (x13, x14) are concavely tapered for cooperating with the axial end surfaces (x10, x12), such that the cooperating axial end surfaces (x10, x12) and the axial contact surfaces (x13, x14) which are inclined under an axial load interact to generate a locking force directed in the radial direction upwards in the transverse direction of the locking member (x07) (x07) remains in the engaged position.

2. Threadless pipe coupling according to claim 1, wherein both of the axial end faces (x10, x12) are inclined and converge outwardly at the same angle, and the axial contact surfaces (x13, x14) have equally formed angled surfaces.

3. Threadless pipe coupling according to claim 1 or 2, wherein the minimum distance between the converging axial contact surfaces (x14, x13) is d1 and the maximum distance between the axial end faces (x10, x12) is substantially d 1.

4. Threadless pipe coupling according to claim 1 or 2, wherein at least one axial contact surface (x13, x14) is provided with a circumferential recess (x62) provided in a region closest to the centre axis of the threadless pipe coupling (x00), and the facing axial end face (x10, x12) is provided with a circumferential shoulder (x63) adapted to engage the circumferential recess (x62) when the locking member is placed in the slot (x 08).

5. Threadless pipe coupling according to claim 1 or 2, wherein the first axial end face (x10) of the locking member (x07) cooperates with an axial abutment face (x11) provided on the plug (x02), and the second axial end face (x12) of the locking member (x07) opposite to the first axial end face (x10) cooperates with the axial contact surface (x13) provided on the socket (x01) so as to withstand tensile axial forces pulling the plug (x02) and socket (x01) away from each other.

6. Threadless pipe coupling according to claim 1 or 2, wherein the locking member (x07) is horseshoe shaped with a first leg (x26) and a second leg (x27), the distal ends (x28, x29) of the first leg (x26) and the second leg (x27) being separated by a gap, and the proximal ends opposite the distal ends (x28, x29) being connected to each other by a bridge (x 30).

7. Threadless pipe coupling according to claim 6, wherein the locking member (x07) is a spring clip configured to engage around the plug (x02) by snap-fit.

8. Threadless pipe coupling according to claim 5, wherein the locking member (x07) does not extend outside the protruding profile (x34) of the surface of the socket (x01) in the inserted position, as seen in a projection in an axial direction parallel to the insertion direction (10).

9. Threadless pipe coupling according to claim 6, wherein the locking member (707) is provided with an extension flap (750, 751) hinged to the distal ends (728, 729) of the first and second legs (726, 727).

10. Threadless pipe coupling according to claim 1 or 2, wherein one or more gripping means (x32, x33, x35, x36, x37, x38) are provided on the locking member (x07) for gripping the locking member (x07) for removing the locking member (x07) from the insertion position.

11. Threadless pipe coupling according to claim 1 or 2, wherein the threadless pipe coupling comprises a plurality of locking members (x 07).

12. Threadless pipe coupling according to claim 1 or 2, wherein the sealing member (x03) is pre-mounted on the outer surface (x04) of the plug (x 02).

13. Threadless pipe coupling according to claim 1 or 2, wherein the threadless pipe coupling (x00) comprises a plurality of sealing members (x 03).

14. Threadless pipe coupling according to claim 1 or 2, wherein the threadless pipe coupling further comprises radial guiding/centering means (x47) and/or axial support means (x23, x24) in order to reduce any slack of the threadless pipe coupling (x00) when the plug (x02) is tilted and/or inclined with respect to the socket (x 01).

15. Threadless pipe coupling according to claim 1 or 2, wherein the circumferential outer surface (x04) of the plug (x02) and the mating inner surface (x05) of the circumferential side wall (x06) of the socket (x01) have a circular cross-section.

16. Threadless pipe coupling according to claim 8, wherein the plug (x02) of the threadless pipe coupling (x00) as assembled is freely rotatable relative to the socket (x01) about a Central Axis (CA) parallel to the axial direction.

17. Threadless pipe coupling according to claim 8, wherein the threadless pipe coupling is provided with stop means (x43, x44) to prevent the plug (x02) from rotating relative to the socket (x01) around a Centre Axis (CA) parallel to the axial direction.

18. Threadless pipe coupling according to claim 1 or 2, further comprising a protective sleeve (x40), wherein the protective sleeve (x40) encapsulates the locking member (x07) in the inserted position and seals the slot (x08) of the socket (x 01).