Patent Description:
In the state of the art a plurality of fittings is known.

For example <CIT> discloses a fitting or mounting for producing a press joint with an inserted tube end. It is proposed that the fitting has an end section which can be crimped in order to produce a connection with a tubular component. It is proposed that in an annular bead at least one bulge or indentation is provided to establish a clearance between a sealing ring located in the annular bead and the wall of the end section. The clearance provides a deliberate leakage between the tubular component and the fitting before the crimping of the end section is carried out.

Such a fitting generally only works fine with comparable low pressures. Especially for low pressures the crimping provides sufficient force to establish a force fit between the tubular component and the fitting. However, in case the pressure within the tubular element is increased and/or a force is acting on the tubular element the connection between the fitting and the tubular component might become loose.

In the state of the art further fittings have been proposed to increase a connection between the fitting and the tube. For example <CIT> discloses a tubular press fitting. The press fitting comprises on the inner side at least one tooth element. When pressing the press fitting the tooth element cuts into the outer surface of the tubular element.

Also <CIT> shows a fitting for connecting a tube that uses a comparable connection mechanism. It is proposed that the fitting comprises a pressing section. The pressing section comprises at least two cutting blades which are fixly connected on the inner side of a hollow body of the fitting. When the pressing section is compressed the cutting blades cut into the outer surface of the tube.

<CIT> discloses a coupling installed by crimping, which has an angularly oriented conical surface at an open end surrounded by a ring which receives a pipe element. Dies move radially toward the coupling on jaws of a crimping tool and engage the conical surface along a single line of contact to effect a crimp which secures the coupling to the pipe. A channel for a seal is defined by a respective bulge.

<CIT> discloses a fitting including a substantially cylindrical sleeve and a swage ring. An inner surface of the sleeve includes continuous, circumferentially extending protrusion rings that create corresponding waveforms on a pipe section introduced in the sleeve after swaging.

The shown fittings have however the drawback that the connection force is not sufficient to ensure a secure fastening of the tube within the fitting also when the tube is used in ACR applications (air conditioning and refrigeration applications). In such systems fluids with high pressures are used. At the moment the standard pressure for ACR applications is <NUM> bar but it is planned to increase the standard pressure to <NUM> to <NUM> bar for efficiency reasons. At such pressures the fittings known in the state of the art could not secure a sufficient secure and stiff connection between the fitting and the tube. It has been observed that already below a pressure of <NUM> bar in fittings known in the state of the art the tube starts to move out of the fitting.

It is thus the object of the invention to further develop the fittings known in the state of the art to allow a use of the fitting in systems using pressures of a fluid above <NUM> bar, especially to provide a fitting that securely fastens the tube to a fitting at such high pressures.

This object is achieved by a fitting according to claim <NUM>.

Dependent claims <NUM>-<NUM> define preferred embodiments of the fitting.

The invention furthermore provides a tubing connection according to claim <NUM>.

Dependent claims <NUM> to <NUM> define preferred embodiments of said tubing connection.

An inventive tubing might also be characterized in that the tubular element and/or the fitting comprises at least one metallic material, especially copper, iron, steel, stainless steel, brass, cast material and/or forged material, at least one carbon material and/or at least one plastic material, especially polymethylmethacrylate, polycarbonate, polyvinyl chloride, glass fiber and/or reinforced plastic, and/or combinations of at least two of the before mentioned materials.

Furthermore the invention provides a method according to claim <NUM> for connecting at least one fitting to at least one tubular element.

Dependent claims <NUM> to <NUM> define preferred embodiments of said method.

A crimp in the sense of the invention is an indentation on the outer surface of the tubular element and/or the inner surface of the fitting wherein the thickness of the wall of the tubular element and/or fitting is/are however constant over the area of the indentation.

In comparison to cutting elements known in the state of the art that produce a cut into the outer wall of the tubular element a crimp in the sense of the invention does not weaken the structure of the tubular element/fitting. Especially in fittings known in the state of the art that use cutting elements it can be observed that the cutting elements lead to a weakening of the structure. When high pressures are used especially the tubular element tends to break in the area of the cut.

In comparison to such a cutting element a hook in the sense of the invention if at all only deforms a corresponding surface of the tubular element fitting but does not cut into the surface. Depending on the material used for the fitting and the tubular element the respective crimp and/or the respective hook element might be pre-formed in the tubular element, for example in case the tubular element comprises plastic materials.

In case the tubular element and/or the fitting comprise(s) for example a metal material it is possible that by reducing the diameter of the pressing section of the press fitting, for example by a press tool, the respective crimp(s) and/or the respective corresponding hook element(s) is/are formed within the tubular element by a hook element and/or the press tool. Due to the fact that the hook is annular, that means is running around the whole periphery of the fitting, it is secured that the form fit leads to the effect that the tube cannot be disconnected from the fitting also when pressures of more than <NUM> bar are used.

The inventive fitting has especially been tested for pressures of about <NUM> bar and no movement of the tubular element with the spectrum fitting could be observed but the test equipment failed.

To provide a sealing of the connection of the fitting with the tubular element the invention defines that a sealing element is provided. The sealing element could be an elastomeric seal that is located within an annular recess. For example the seal might comprise an O-ring. Such a seal might also be used as an indication for a missing connection of the tubing element and the fitting.

In case the seal is dimensioned to have a greater inner diameter in comparison to the auto diameter of the tubular element a leakage is occurring in case the fitting is not pressed. Alternatively the sealing element might comprise a viscouse fluid type sealant contained within a suitable receptacle that may be essentially circular and located in place of or adjacent to the O-ring. The pressing action, when reducing the diameter of the press fitting ruptures the receptacle and releases the sealing liquid.

A fitting might furthermore comprise at least one second end section. This second end section might have any form and function, for example allowing a connection of the fitting to an additional tubular element. This second end connection might allow a connection with an additional tubular element in any way known in the state of the art. The connection to the additional tubular element might be preferably reached by a threaded connection or by a connection element comprising a hook that engages a crimp that are provided within the fitting and further tube, respectively.

Also other connection types for connecting the fitting to another tube maybe used, like click connections, connections via an adhesive material or by welding.

Especially the fitting might be formed as a distributor that means that the fitting comprises a plurality of sections that are directed into different directions, especially off set from a longitudinal axis of the first end section.

To secure a correct positioning of the respective hook relative to the respective crimp, that is/are especially preformed the invention furthermore proposes at least one a alignment element. To reach a coincidence of the hook element with the internal projection within the fitting, especially a circumferential projection might be used. The projection engages with the tube end such that a distance between the projection and the hook element is approximately the same as the distance of the end of a tube element and the crimp.

To further secure the connection between the tubular element and the fitting an additional crimping or cutting element might be provided. Probably such a gripping or cutting element does not cut into the outer surface of the tubular element when the diameter of the fitting is reduced. However in case the tubular element tends to move out of the fitting the gripping element engages the outer surface of the tubular element and hinders the tubular element from a further movement out of the fitting. In such a case the displacement of the tubular element with respect to the fitting can be seen from outside as the hook will not anymore fully engage the crimp and thus becomes visible at least partly.

As already mentioned the structure of the inventive fitting elements allows that the fitting and on/or the tubular element to be made of a variety of different materials, like metallic materials and/or plastic materials and combinations. Thus the fitting becomes useable for nearly any function within an ACR-application.

The reduction of the diameter of the fitting may be reached in different ways. The reduction might be reached by a pressing tool. However it is also possible that the reduction or deformation of the fitting element is achieved by means of an external cap that is shaped to urge a diametrical reduction pressed into a place by an axial pressing of the cap into the fitting. To reach this aim the cap might have a frustoconical cross section such that when the cap is pushed onto the fitting the diameter of the fitting is reduced. The pushing movement might be reached by a turning action to connect the cap to the fitting by a thread and/or a bayonet connection. In general the invention covers any radial movement, linear movement or combination of such movements of a tool or member that leads to an introduction of the hook element into a tubular element, especially a crimp, irrespective whether the tubular element has been preformed, especially whether the crimp has been preformed or not.

Further aspects and advantages of the claimed invention become apparent from the following description of preferred embodiments of the invention that are explained with the help of the following figures in which.

<FIG> shows a cross sectional view of a tubing connection according to a first aspect of the invention. The tubing connection <NUM> comprises a fitting <NUM> and a tubular element <NUM>. As can be taken from <FIG> the tubular element <NUM> comprises a crimp <NUM> forming a second crimp in the sense of the claims formed on the outer surface of the tubular element.

The thickness of the wall of the tubular element <NUM> is constant over the whole length of the tubular element <NUM>, especially in the area of the crimp <NUM>. The fitting <NUM> comprises a first section <NUM> including a first connection element <NUM>. Furthermore the fitting <NUM> comprises a second end section <NUM> comprising a second connection element in form of a thread <NUM>.

In the area of the end section <NUM> furthermore an annular grove <NUM> is provided in which a first sealing element in form of an O-ring <NUM> is located. According to the invention the first connection element <NUM> comprises a hook element <NUM> forming a first hook element in the sense of the claims. The hook element <NUM> is formed as an annular element that is projecting radially inwardly from the fitting <NUM>.

To connect the fitting <NUM> to the tubular element <NUM> to provide the tubing connection <NUM> the tubular element <NUM> is introduced into the fitting <NUM> such that an end <NUM> of the tubular element <NUM> engages an alignment element in form of a step <NUM>. With the step <NUM> it is secured that the crimp <NUM> is aligned with the hook <NUM>. With a pressing tool known in the state of the art the end section <NUM> is then compressed such that the diameter of the fitting, especially of the area of the hook <NUM>, is at least partly reduced, such that the hook <NUM> engages in a form-fit and force-fit manner into the crimp <NUM>. As already described above in <FIG> an embodiment of the invention is shown in which the end section <NUM> having the inventive hook <NUM> is combined with a threaded section <NUM>.

As can be taken from <FIG> the invention might however be also utilized such that the fitting comprises two end sections comparable to the end section <NUM>. In <FIG> the tubing connection <NUM>' does comprises an end section <NUM>' and an end section <NUM>'.

The elements of the tubing connection <NUM>' that are functionally corresponding to the elements of the tubing connection <NUM> have the same reference number, however ticked. In comparison to the step <NUM> in the tubing connection <NUM>' a circumferential projection <NUM>' is provided. Furthermore the end section <NUM>' comprises an annular grove <NUM>' comparable to the grove <NUM>' and a hook element <NUM>' representing a third hook element in the sense of the claims comparable to the hook element <NUM>'.

Thus to connect the tubular elements the tubular elements are inserted into the fitting <NUM>' and the end section <NUM>' as well as the end section <NUM>' are pressed such that at least a part of the diameter of the respective end sections, especially in the area of the hooks <NUM>', <NUM>', is reduced. Variations of such fittings and tubing connections provide multiple sockets with different angular directions and/or tube diameters. The tubular element <NUM> as well as the fitting <NUM> may be metallic or made of plastic.

In <FIG> a detail view of the section A in <FIG> is shown. From <FIG> it becomes especially apparent that the (first) hook <NUM>' is positioned to coincident with a preformed circumferential indentation forming the (second) crimp <NUM>'. To provide a coincident of the hook <NUM>' and the crimp <NUM>' an inclusion of an internal circumferential projection <NUM>' to engage with a tube end <NUM>' is used. In this way the distance between the hook element <NUM>' and the projection <NUM>' is approximate to the distance between the crimp <NUM>' and the tube end <NUM>'. As it is furthermore shown in <FIG> in the area of the grove <NUM>' a gripping element in form of a sharp edge <NUM>' is utilized to provide additional tube engagement, especially in case a movement of the tubular element <NUM>' relative to the fitting <NUM>' occurs.

In <FIG> a partial cross sectional view of a third embodiment of a tube connection <NUM> is shown. The elements of the tube connection <NUM> that correspond to the elements of the tube connection <NUM> and <NUM>', respectively, have the same reference numbers, however increased by <NUM>.

In comparison to the before described embodiments in the embodiment shown in <FIG> at least partly pressing of the first connection <NUM> is reached by a cap element <NUM>. As can be seen from <FIG> the cap <NUM> has an inclined inner surface such that when the cap <NUM> is pushed into the direction B in <FIG> the first connection element <NUM> is compressed, especially the hook element <NUM> is forced into the crimp <NUM>. The movement of the cap <NUM> might be reached by a not shown thread.

In <FIG> the partial cross sectional view of a fourth embodiment of a tube connection <NUM> is shown. The elements of the tube connection <NUM> that correspond to the elements of the tube connection <NUM> have the same reference numbers, however increased by <NUM>.

In contrast to the before described embodiments the respective hook element of the first connection element is not formed in the fitting <NUM> but is provided in the tubular element in form of a hook element <NUM> representing a second hook element in the sense of the claims. The hook element <NUM> is cooperating with a crimp <NUM> that is formed in the fitting <NUM> and represents a first crimp in the sense of the claims.

In <FIG> the tube connection <NUM> is shown in the connected status. This means that the fitting <NUM> has at least partly been compressed, especially in the area of the first connection element <NUM> such that the crimp <NUM> engages in a force-fit and form-fit manner the hook <NUM> formed in the tubular element <NUM>. Before the compression the crimp <NUM> had a greater diameter to receive the tubular element <NUM>, especially the hook <NUM>. Especially an end element <NUM> provided a diameter of the fitting <NUM> that was greater than the diameter of the tubular element <NUM> in the area of the hook <NUM>.

<FIG> shows a partial cross sectional view of a fifth embodiment of a tube connection <NUM>. The elements of the tube connection <NUM> that correspond to the elements of the tube connection <NUM> have the same reference number, however increased by <NUM>.

The tube connection <NUM> mainly differs from the tube connection <NUM> in that neither the (second) crimp <NUM> nor the (first) hook element <NUM> have been preformed in the tubular element <NUM> and a fitting <NUM>, respectively. Both the crimp <NUM> and the hook element <NUM> have been formed when the diameter of the first connection element <NUM> has been at least partly reduced.

Thus in the unconnected state the fitting <NUM> and the tubular element <NUM> have a mainly flat or cylindrical cross sectional form. However by the pressing the hook element <NUM> is formed and due to the pressure that is transferred via the hook element <NUM> onto the surface of the tubular element <NUM> the crimp <NUM> is formed. However still a form-fit between the crimp <NUM> and the hook element <NUM> is reached such that due to the annular form of the hook element <NUM> and the crimp <NUM> a relative movement between the tubular element <NUM> and the fitting <NUM> also it high pressures is avoided.

In <FIG> a sixth embodiment in form of a tube connection <NUM> is shown. The elements of the tube connection <NUM> that correspond to the elements of the tube connection <NUM> have the same reference number, however increased by <NUM>.

In contrast to the tube connections <NUM>, <NUM>', <NUM>, <NUM>, <NUM> described before the form-fit and force-fit connection between the fitting <NUM> and the tubular element <NUM> is not reached by a hook/crimp connection but a connection between two crimps. Similar to the tube connection <NUM> the tubular element <NUM> comprises a (second) crimp <NUM>. Comparable to the tube connection <NUM> the fitting <NUM> comprises a (first) crimp <NUM>. To reach a form-fit and force-fit connection between the crimps <NUM>, <NUM> in the crimps a securing element in form of a latch ring <NUM> is positioned. To connect the tubular element <NUM> to the fitting <NUM> the latch ring <NUM> is located within the crimp <NUM>, when the fitting <NUM> is pushed over the tubular element <NUM>. However at this point of time before a pressing of the fitting <NUM> the diameter of the tubular element <NUM> is increased, especially in the area of the crimp <NUM> such that the latch ring <NUM> can be located in the area of the crimp <NUM>. When the diameter of the first connection element <NUM> is at least partly reduced the crimp <NUM> engages the latch ring <NUM> leading to a form-fit and force-fit connection of the tubular element <NUM> and the fitting <NUM>.

<FIG> shows a cross sectional view of a tubing connection <NUM> according to a seventh embodiment. The elements of the tubing connection <NUM> which corresponds to the elements of the tubing connection <NUM> have the same reference number, however increased by <NUM>. Similar to the tubing connection <NUM> the tubing connection <NUM> comprises a cap <NUM>. The cap <NUM> forms a part of the fitting <NUM> which comprises a fitting body <NUM> and the cap <NUM> in form of a sleeve.

Furthermore the tubing connection <NUM> differs from the before described tubing connections, especially fittings, in that the hook element <NUM> is formed by a plurality of teeth <NUM> that are formed on a plurality of tongues <NUM>. In addition to the teeth <NUM> covering only a part of the circumference of the tubular element <NUM> respectively, the tongues <NUM> furthermore comprises respective sleeve retainers <NUM>.

In <FIG> the tubing connection <NUM> is shown in a preconnected state, that means the hook element <NUM> is in a form-fitted manner but not in a force-fitted manner connected to the crimp <NUM>. By pushing the sleeve <NUM> into the direction of the fitting body <NUM> the engagement surface <NUM> on the inside of the sleeve <NUM> gets into contact with the surface of the hook element <NUM> such that a radially outward movement of the hook element <NUM> is prohibited as shown in <FIG>. Furthermore in this position an engagement element <NUM> is in connection with the sleeve retainer <NUM> such that the sleeve <NUM> is hold in the position shown in <FIG>.

In not shown embodiments the sleeve and the fitting might be connectable via a threaded connection and/or a bayonet connection. Thus by a rotational movement of the sleeve a longitudinal movement of the sleeve along the fitting is caused.

In <FIG> a partial cross sectional view of an eighth embodiment in form of a tubing connection <NUM> is shown. The elements of the tubing connection <NUM> with corresponds to the elements of the tubing connection <NUM> have the same reference number, however increased by <NUM>. The tubing connection <NUM> comprises a metallic fitting <NUM> and a tubular element <NUM> which is made at least partially of a plastic material.

To allow an electrical connection via the tubular element <NUM> the tubular element comprises a conductive pipe layer <NUM>. Furthermore the tube connection <NUM> comprises a pipe insert <NUM>. The pipe insert <NUM> is inserted partly into the tubular element <NUM> and comprises a indentation. This indentation might have the form of a fifth crimp <NUM> having a continuous thickness but might also be formed by a cut out, a pressed indentation or any other forming style.

Furthermore the pipe insert <NUM> comprises a first clearance <NUM> into which a second sealing element in form of an O-Ring <NUM> is inserted. By the O-Ring <NUM> a gap between the tubular element <NUM> and the pipe insert <NUM> is sealed. Furthermore the pipe insert <NUM> comprises a second clearance <NUM> into which a third sealing element in form of an O-Ring <NUM> is inserted. By the O-Ring <NUM> a gap between the pipe insert <NUM> and the fitting <NUM> is sealed.

In <FIG> the tube connection <NUM> is shown in a connected state. As can be taken from the <FIG> by pressing a part of the connection <NUM> in a radial direction the tubular element <NUM> has been deformed in the area of the hook element <NUM> and the crimp <NUM>, respectively. By this deformation a first crimp <NUM> is formed within the tubular element <NUM>. As can be taken furthermore from <FIG> the step <NUM> fulfils the function of an alignment element to align the pipe insert <NUM> relative to the fitting <NUM>. Furthermore by a step <NUM> formed within the pipe insert <NUM> the tubular element <NUM> is aligned relative to the pipe insert <NUM> and thus relative to the fitting <NUM>.

The use of the pipe insert <NUM> further allows a user to better check the correct position of the fitting <NUM> relative to the tubular element <NUM> by a marking process. For this purpose the user can use the step <NUM> to align the pipe insert <NUM> with the tubular element <NUM> before the pressing of the fitting <NUM>. In a first step the user positions the end of the tubular element <NUM> side by side to the pipe insert <NUM> such that the step <NUM> abuts the end <NUM> of the tubular element <NUM>. The user then marks on the outside of the tubular element <NUM> where the fifth crimp <NUM> is located. In other words the user uses the crimp <NUM> as a guidance for a depth marking. In the next step the user then inserts the pipe insert <NUM> into the tubular element <NUM> as shown in <FIG> and presses the fitting <NUM>.

In case the tubing connection <NUM> is connected in the correct way the position of the marking will fall under the hook element <NUM>. Thus in case the position of the marking and the hook element <NUM> will not fall together it is indicated to the user that the fitting <NUM> is not connected correctly.

In <FIG> variations of the tube connection <NUM> are shown. As can be taken from a comparison of <FIG> and <FIG> the crimp <NUM> within the pipe insert <NUM> might have different cross sectional forms.

Furthermore the tube connection might comprise, as shown in <FIG>, a pipe conductor <NUM> leading to an electrical connection of the pipe insert <NUM> with the pipe layer <NUM>.

Such a connection might also be provided by a pipe layer <NUM> that extends out of the tubular element <NUM> as shown in <FIG>.

In <FIG> a ninth embodiment of a tubing connection <NUM> is shown. The elements of the tubing connection <NUM> which correspond to the elements of the tubing connection <NUM> have the same reference number, however increased by <NUM>.

As can be taken from <FIG> the pipe insert <NUM> might have a flat or plain surface, especially might not have an additional crimp. Irrespective of this missing crimp by a pressing of the connection <NUM> the hook element <NUM> deforms the tubular element <NUM> such that a crimp <NUM> is formed that is in form-fit and force-fit connection to the hook element <NUM>.

In <FIG> a tenth embodiment in form of a tube connection <NUM> is shown. The elements of the tubing connection <NUM> that correspond to the elements of the tubing connection <NUM> have the same reference number, however increased by <NUM>.

In comparison to the tube connection <NUM> the tube connection <NUM> comprises a pipe insert <NUM> that provides a gripping structure on the outer surface in form of teeth <NUM>.

A variation of the tubing connection <NUM> is shown in <FIG> in form of an eleventh embodiment formed by a tubing connection <NUM>. Elements of the tubing connection <NUM> corresponding to tubing connection <NUM> have the same reference number, however increased by <NUM>. In the tube connection <NUM> the pipe insert does not provide a crimp corresponding to the crimp <NUM> but nearly the complete outer surface of the pipe insert <NUM> is formed with a gripping structure comprising teeth <NUM>.

Claim 1:
Fitting (<NUM>, <NUM>') for connecting to a tubular element (<NUM>, <NUM>') having an axial first end section (<NUM>, <NUM>', <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), the fitting comprising at least one first connection element (<NUM>, <NUM>', <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and at least one first sealing element arranged at least partly in a radially outwardly extending annular recess (<NUM>, <NUM>'), wherein the diameter of at least a part of the first connection element (<NUM>, <NUM>', <NUM>, <NUM>, <NUM>, <NUM>) can be reduced in a radial direction in order to produce a connection, wherein the first connection element comprises at least one radially inwardly extending first hook element (<NUM>, <NUM>', <NUM>, <NUM>, <NUM>, <NUM>) being preformed in the fitting (<NUM>, <NUM>'), being formed as an element that runs circumferentially around the whole periphery of the fitting such that the hook element defines said axial end section of the fitting, and being configured to be connected in force-fit and form- fit manner to at least one first crimp (<NUM>, <NUM>', <NUM>, <NUM>, <NUM>, <NUM>) formed on the outer surface of the tubular element (<NUM>, <NUM>', <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) when the diameter of at least a part of the connection element is reduced, and wherein the radially outwardly extending annular recess (<NUM>, <NUM>') additionally forms a gripping element for engaging the outer surface of the tubular element and that is axially spaced apart from the first hook element (<NUM>, <NUM>', <NUM>, <NUM>, <NUM>, <NUM>).