Coupling and a valve assembly for tubeless tires, and related fitting method

A coupling for valve assemblies, for tubeless tires, includes an enclosure arranged to cover a rigid rim of a vehicle, to delimit a substantially tubular compartment, filled with gas under pressure. The coupling has a first element and a second element crossed respectively by a first through channel, threaded internally, and by a second through channel. The second element cooperates with a valve for the selective closure of the second channel. The first element rests on an internal surface of the rim, which can be activated following its hermetic insertion, from the inside of the compartment. The second element rests on an external surface of the rim, which can be activated following the hermetic screwing, from the outside of the compartment, of a threaded stem of the second element in the first channel, with consequent alignment between the channels to connect the compartment to the outside.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a U.S. National Stage Entry of International Patent Application No. PCT/IB2016/053583, filed Jun. 16, 2016, which claims the benefit of Italian Patent Application No. 102016000041591, filed Apr. 22, 2016, the disclosures of which are hereby incorporated entirely herein by reference.

TECHNICAL FIELD

The present invention relates to a coupling and a valve assembly for tubeless tires, and the relevant fitting method.

BACKGROUND ART

As known, the tires are deformable enclosures, typically made of blends, which cover the rigid rims of bicycles, motorcycles and vehicles in general; a tubular compartment is delimited between rims and tires in which air under pressure is supplied.

According to well-established procedures, each tire is associated with a respective valve assembly, through which it is possible to introduce air or let it flow out, so as to bring the pressure inside the compartment to the desired value.

In conventional tires, the valve assembly leads into an inner tube in turn contained in the compartment while, in the most recent “tubeless” type models, without inner tube, the valve assembly allows to put the external environment directly in communication with the tubular compartment.

More in detail, and precisely with specific reference to “tubeless” tires, the valve assembly comprises an axially symmetrical main body crossed by a longitudinal duct: during fitting, from the inside of the compartment the main body is hermetically inserted in a hole previously made along the surface of the rim, and then made partially protruding from the hole itself.

This way, one portion of the body is maintained protruding outwards: through this, it is possible to introduce air into the compartment, towards which the opposite end of the main body remains facing.

More precisely, the duct is normally locked by a piston supported by an internally hollow needle, in turn screwed on the head of the body, at the end of the protruding portion. When the user wishes to inflate the tire, it is sufficient to temporarily move the plunger and introduce air in the needle by means of a pump previously hooked to the needle at the head of the main body.

This embodiment is not however devoid of drawbacks.

In the fitting phase, to obtain the desired coupling and tightness, at the hole, after having inserted the body from the inside and made it partially protrude, a threaded ring has to be screwed on the protruding portion, so as to tighten the edges of the hole between the ring itself and the base of the main body, remained inside the compartment.

This operation inevitably leaves protruding outwards a portion of the body having a different length from time to time, depending on the size and the shape of the rim, and/or of the other associated components.

This proves to be very undesirable, especially under all circumstances in which the protruding portion has a significant length. As already noted, in fact, to inflate the tire, the user must mate a pump at the head of the main body, and then at the end of its protruding portion.

Therefore, when the body protrudes significantly, in the mating step and subsequently during inflation operations, the user often subjects his/her body to stress that, as a result of the elevated arm, cause bending moments and torques of significant intensity, that may result in breakage or unwanted deformation.

DESCRIPTION OF THE INVENTION

The main aim of the present invention is to solve the aforementioned problems by providing a coupling and an assembly that ensure high resistance to stress, avoiding or at least limiting the risk of breakage or deformation.

Within this aim, one object of the invention is to provide a coupling and a method which enable to fit a valve assembly on a tubeless tire, controlling the length of its external portion, protruding from the tire.

Another object of the invention is to provide a versatile coupling and valve assembly, easily adaptable to any type of tubeless tire and pump (or other inflating device).

Not the least object of the invention is to provide a coupling, a valve assembly and a method that ensure high reliability in operation, affordable costs, safe application and that they are easily obtainable starting from elements and materials commonly available on the market.

Another object of the invention is to provide a coupling and a valve assembly that adopt a technical and structural architecture alternative to those of known assemblies.

This aim and these and other objects that will become better evident hereinafter are achieved by a coupling according to claim1.

This aim and these objects are also achieved by an assembly according to claim8.

This aim and these objects are also achieved by a method according to claim15.

EMBODIMENTS OF THE INVENTION

With particular reference to the aforementioned figures, reference number1globally designates a coupling for valve assemblies100, which can find typical application on tubeless tires A, comprising an enclosure B arranged so as to cover a rigid rim C of a vehicle (of any type). This way, in fact, and in a known manner, the tire A and the rim C delimit a substantially tubular compartment D (precisely surrounding the rim C), which is filled with a gas under pressure (typically air) so as to allow optimal support and grip to the ground, for the rim C itself and the vehicle.

It should be explained that in the typical application the tire A is preferably intended to cover rims C of bicycles, but it can also cover rims C of other vehicles. In any case, the tire A is of the “tubeless” type, i.e. the compartment D is without inner tubes and is intended to be entirely filled with air under pressure (through the coupling1and the assembly100, as will be seen).

According to the invention, the coupling1comprises a first element2and a second element3which are crossed by a first through channel2a, which is (completely or partially) internally threaded, and by a second through channel3a, respectively.

As will be illustrated in more detail below, the second element3is adapted to cooperate with a valve101(also of known type), which is comprised in the assembly100and that is able to selectively close the second channel3a, so as to prevent the passage of air until the tire A is inflated or deflated.

It should be specified since now that the protection claimed herein first of all encompasses couplings1wherein, as in the accompanying figures, the valve101is a separate component, distinct from the second element3. In this case, therefore, the valve101is not part of coupling1according to the invention but is comprised in the assembly100, to which in any case the invention is related. Likewise, the scope of protection outlined herein must certainly be understood as extended to couplings1according to the invention which comprise the valve101, since it is integrated in the second element3and can be of the type which will be described in the following pages, or even different, anyway able to prevent and selectively permit the passage of air.

The first element2comprises first means for stable resting on an internal surface E of the rim C (such internal surface E is then directly facing the compartment D). As further explained hereinafter, these first means can be activated automatically when, from the inside of the compartment D, the first element2is inserted, hermetically, in a hole F made along the rim C.

The second element3in turn comprises second means for stable resting on an external surface G of the rim C (such external surface G is then directly facing the external environment), which can be activated (automatically) when, from the outside of the compartment D, a threaded stem3bof the second element3itself is screwed in the first channel2a.

It should also be noticed that with the screwing of the stem3bis first of all possible to mate the two aforementioned elements2,3and, at the same time, to align the channels2a,3a, in order to connect the compartment D to the outside, through precisely the latter.

Air can therefore run through the aligned channels2a,3ato enter or exit the compartment D.

In addition, the coupling1, which performs a similar function of a single body piece in known valve assemblies, is stably mated to the rim C, since from the inside and the outside, the first element2and the second element3, respectively, abut and rest against corresponding surfaces E, G, thus preventing any relative movement by interference.

It should also be specified that the first means and the second means are typically intended to rest against surfaces E, G of the rim C, but their reference to the surfaces of a different component cannot be ruled out, without thereby departing from the scope of protection claimed herein.

It is noticed that, to obtain the desired tightness between the stem3band the first channel2a, the former has to perform a short screwing stroke, so as to engage some spirals of its threads with respective spirals of the threads of the first channel2a.

Nevertheless, in an improved embodiment, precisely to ensure an optimum tightness of the mating obtained with the screwing of the stem3bin the first channel2a, at least one of them (and preferably the stem3b) is spread beforehand with a sealing substance, of the Teflon type (which is a registered trademark) and the like.

Following the screwing, in fact, the sealing substance (whether it is Teflon, which is a registered trademark, or other) completely fills also the minimum cavities that may possibly be formed between the threads of the stem3band of the first channel2a, hindering also the minimum passage of air and therefore precisely ensuring an optimum tightness.

In an embodiment of significant practical interest, given in the accompanying figures as an illustrative and non-limiting application of the invention, the first element2comprises a substantially cylindrical bush4, which is crossed longitudinally by the first channel2aand which can be inserted hermetically in the hole F.

In this embodiment, the first means are constituted substantially by a tangential expansion4aof the bush4, suitably chosen of dimensions greater than those of the hole F (usually standard).

Thus, when the bush4is inserted hermetically in the hole F, the expansion4ais intended to stably rest on the internal surface E of the rim C (surrounding the hole F), preventing further moving forward by mechanical interference.

In a first possible embodiment, it is the bush4that is directly brought to press against the edge of the hole F, to achieve the desired tightness.

In the preferred solution, on the other hand, illustrated in the attached figures, the bush4(or in any case the first element2) is covered externally with a first gasket5(usually made of rubber or other elastomeric material).

This way, it is precisely the first gasket5that is pressed against the edge of the hole F: thanks to the elastic properties of the material with which it is made, it can adapt to the shape and any imperfection of the hole F to the best, precisely ensuring an optimal tightness of the mating obtained as a consequence of the insertion of the first element2in the hole F.

With further reference to the solution illustrated in the accompanying figures, the second element3is constituted by a substantially axially symmetrical tube (suitably shaped, as will be seen), which is precisely crossed by the second channel3athat forms, with its end portion, the stem3b.

In this preferred but not exclusive embodiment, the second means of stable resting are constituted by an intermediate portion of the tube, which is contiguous to the stem3b, and forms externally a sort of knurled ring6.

The ring6thus performs a dual function: thanks to knurling, it can first be easily tightened by a respective tool (pliers or the like, such as will be shown below), to obtain the facilitated movement of the stem3b, and of the tube (in particular to screw or unscrew it). Moreover, it is precisely the ring6that is intended to rest stably on the external surface G of the rim C, as a consequence of the hermetic screwing of the stem3bin the first channel2a.

Similarly to the expansion4a, the ring6causes the stop of the screwing of the stem3bin the first channel2aand prevents further strokes.

As a matter of fact, therefore, in the preferred (not exclusive) solution the rim C remains tightened between the expansion4aand the ring6, resulting in the stable mating between the coupling1and the rim C (whatever the size and the shape of the latter).

It is specified that it is envisaged the possibility to place a second gasket externally to the tube, between the ring6and the stem3b, so as to obtain an optimal resting on the external surface G of the rim C.

Advantageously, the tube also has an external groove7, substantially on the opposite side with respect to the stem3b, for mating to a protective cap, which can be arranged so as to cover the second element3.

Note how simply varying the groove7(and therefore with minimal changes to the second element3and maintaining the same first element2) it is possible to adapt the coupling1to different types of cap or otherwise prepare it for mating with different structures, ensuring high versatility to the invention.

A special example of a protective cap to be fitted on the tube is shown inFIGS. 5 to 7and will be described in more detail below.

This invention (and the protection claimed herein) also relates to a valve assembly100, intended for tubeless tires A which, as already observed, comprise an enclosure B normally arranged so as to cover a rigid rim C of a vehicle, to delimit a substantially tubular compartment D, which can in turn be filled with pressurized gas (typically air).

As far as the extension of the scope of application and protection are concerned, the same considerations apply as indicated in the previous pages in relation to coupling1.

According to the invention, in addition to a coupling1having one or more of the various features indicated in the previous pages, the assembly100comprises a valve101for the selective closure of the second channel3a. More precisely, this valve101is normally arranged so as to hinder the free passage of gas through the channels2a,3a(to maintain the desired pressure value in the compartment D) and can be deactivated selectively (and temporarily) to allow the introduction of gas in the compartment D (typically by means of a pump) and/or the exit of gas from the compartment D (simply by leaving the passage open and exploiting the difference in pressure with the external environment).

It is specified that the assembly100according to the invention can above all comprise three distinct components, constituted precisely by the first element2, the second element3and the valve101.

Likewise, the assembly100can also simply have a first element2and a second component, in which are integrated the second element3and the valve101(of the type that will be illustrated below, or even different).

In one form of embodiment of significant practical interest, mentioned for illustrative and non-limiting purposes for the application of the invention, the valve101comprises a sleeve102axially crossed by a through duct.

Thanks to an external thread103, the sleeve102can be partially screwed into the second element3(in the second channel3a), on the opposite side with respect to the stem3b.

Inside the sleeve102a piston104therefore slides which, when the sleeve102is screwed into the second element3, can be arranged so as to close the second channel3a, in at least one active configuration. In the solution of the attached figures, this is made possible by the shape given to the ending part of the piston104, which replicates that of at least a portion of the second channel3a: in the active configuration, the piston104is arranged in a such a manner that its ending part is in this portion, precisely hindering completely the second channel3a.

The piston104is then movable selectively from the active configuration, to allow the introduction of gas into the compartment D and/or the exit of gas from the compartment D itself.

As is also apparent from the attached figures, the movement of the piston104, which allows to remove it at least partially from the second channel3a, preferably takes place by acting on a shank105of the piston104itself, which protrudes from the opposite side with respect to the sleeve102and which is therefore maintained easily accessible during use.

The valve101shown in the figures is of the type commonly known as “Presta” valve; alternative embodiments cannot however be ruled out in which the valve101is instead of the “Schrader” type or even a different type.

Conveniently, the assembly100also comprises at least one protective cap110having a first internal seat111and arrangeable to at least partly cover the second element3and the valve101.

The protective cap110comprises first tightening means112defining the aforementioned tool for the facilitated movement of the stem3bin screwing and/or unscrewing in the first channel2a.

The first tightening means112comprise at least one serrated surface113that is formed on a portion of the first internal seat111and which is intended to grip on the knurled ring6.

In this regard it is noticed that, in the present context, “serrated surface” means a generic surface having protrusions and recesses, which can consist of a series of teeth and/or of a sort of knurling and which, placed in contact with the knurled ring6, allow the stable gripping of the latter.

The protective cap110is deformable between an inactive configuration, wherein the serrated surface113is moved away from the knurled ring6and the protective cap110is free to rotate around the tube of the second element3, and a work configuration, wherein the serrated surface113is approached to and grips the knurled ring6and the setting in rotation of the protective cap110sets in rotation the knurled ring6around its own axis.

Preferably, the protective cap110is made of plastic so as to be manually pressed by the user to pass from the inactive configuration to the work configuration and elastically return to the inactive configuration when the user stops pressing it.

More in detail, the serrated surfaces113are two and are arranged on diametrically opposite sides to the first internal seat111. The pressing of the walls of the protective cap110allows approaching the serrated surfaces113to the knurled ring6on opposite sides to the same, ensuring the stable gripping of the knurled ring6by the user who, in practice, can use the protective cap110as a maneuvering element to screw and unscrew the second element3with respect to the first element2.

As said, in the inactive configuration the protective cap110is freely rotatable around the second element3. For this purpose the protective cap110comprises an internal raised part114facing the first internal seat111and which engages the external groove7of the second element3. The external groove7has an annular and circular shape and, therefore, the mating between the external groove7and the internal raised part114is such as to allow the protective cap110to rotate around the second element3without the possibility of sliding longitudinally to the coupling1. To remove the protective cap110from the second element3, the user must manually apply a force on the protective cap110directed to force the exit of the internal raised part114from the external groove7and to remove the protective cap110from the coupling1.

Conveniently, the protective cap110comprises an external profile115of wing and aerodynamic shape and, when the protective cap110is in the inactive configuration, the setting in rotation of the rim C during the normal advancement of the vehicle to the ground determines the automatic flag-like positioning of the protective cap110.

The flag-like positioning of the protective cap110means that the cap110is arranged “edgewise” with respect to the flow of air that strikes it during motion. In this position, the external profile115of the protective cap110provides the least possible friction. The flag-like positioning of the protective cap110is automatic, considering that, as said, in the inactive configuration the protective cap110is free to rotate around the second element3and, therefore, the flow of air that strikes it during motion constitutes the only force able to make it rotate.

The protective cap110also comprises second tightening means116for the facilitated screwing of the sleeve102in the second element3.

The second tightening means116comprise at least a second internal seat117formed in the protective cap110and having at least a prismatic section117amateable in a prismatic manner to a corresponding prismatic surface102aof the sleeve102.

In practice, when the user removes the protective cap110from the second element3by disengaging the internal raised part114from the external groove7, then the user can put on again the protective cap110on the valve101, this time no longer at the first internal seat111but rather at the second internal seat117.

The setting in rotation of the protective cap110mated to the prismatic surface102asets in rotation the sleeve102around its own axis and the protective cap110is used as a maneuvering element to screw and unscrew the valve101with respect to the second element3.

Besides the coupling1and the assembly100, the present invention (and the protection claimed herein) also relates to a method for fitting a valve assembly100on tubeless tires A, comprising an enclosure B normally arranged so as to cover a rigid rim C of a vehicle, in order to delimit a substantially tubular compartment D, fillable with gas (air) under pressure (according to what has been already noticed in the previous pages).

The method consists, at a step a., of preparing a first element2and a second element3which are crossed by a first internally threaded through channel2aand by a second through channel3a, respectively.

Subsequently, the method consists, at a step b., of inserting hermetically, from the inside of the compartment D, the first element2in a hole F made along the rim C, until the first element2rests stably on an internal surface E of the rim C.

Then, at a step c. the method provides to screw hermetically, from the outside of the compartment D, a threaded stem3bof the second element3into the first channel2a, until the second element3rests stably on an external surface G of the rim C and with consequent alignment between the channels2a,3a, in order to connect the compartment D to the outside.

Subsequently, at a step d. the method provides to associate with the second element3, on the opposite side with respect to the first element2, a valve101for the selective closure of the second channel3a, which is normally arranged so as to hinder the free passage of gas through the channels2a,3a, and selectively deactivatable to allow the introduction of gas in the compartment D and/or the exit of gas from the compartment D.

It should also be noticed that the step d. can be accomplished in advance, since the present invention also relates to the realization of couplings1and assemblies100wherein the valve101is integrated in the second element3.

At the end of step d., therefore, through the valve assembly100it is first of all possible to prevent the unwanted exit of air from the compartment D, and, where appropriate, taking care to deactivate it temporarily, it is possible to inflate the tire A, attaching a pump to the valve101and/or to the second element3.

The operation of the coupling and of the valve assembly according to the invention is thus already been substantially anticipated in the previous pages, and in any case is the following.

To mate the assembly100to a rim C covered with a tire A (with a delimiting compartment D between them), it is envisaged first of all to insert from the inside of the compartment D, in the hole F, the first element2, carrying the expansion4aresting on the internal surface E of the rim C.

In this condition, the passage of air between the hole F and the first element2is preferably prevented by the first gasket5.

Subsequently, from the outside of the compartment D the stem3bis screwed in the first channel2aof the first element2, and the screwing stroke continues until the ring6rests on the external surface G of the rim C.

When such layout is obtained, the expansion4aand the ring6are evidently pressed against the internal surface E and the external surface G, respectively and therefore prevent any movement of the coupling1(comprising the elements2,3now mutually constrained in a stable manner, thanks to the screwing of the stem3b) with respect to the rim C. In this condition, the air can enter the compartment D or exit only through the channels2a,3a(thanks to the tightness that is achieved between the threads of the stem3band those of the first channel2a), mutually aligned.

The passage of air is regulated by the valve101, which is mated to the coupling1at the free end of the second element3, protruding externally, where, however, also a pump has to be attached (according to modalities known in themselves), when the tire has to be inflated.

In this circumstance, the user must move the piston104from the active configuration thus allowing air to enter in the duct defined internally to the sleeve102; from it, the air no longer hindered by the piston104can be conveyed to the channels2a,3a, and therefore in the compartment D.

While the single body piece present in the known valve assemblies (replaced in the assembly100by the coupling1) protrudes outward with a different portion from time to time, depending on the shape of the rim C and of its size, this doesn't occur using the coupling1according to the invention.

In fact, even when the distance varies between the internal surface E of the rim C (against which the first element2rests) and the external surface G of the rim C (against which the second element3rests), the screwing stroke varies accordingly of the stem3bin the first channel2a, which continues precisely until the second element3rests, with the ring6, on the external surface G of the rim C.

After reaching this condition, the externally protruding portion of the coupling1(of the second element3) is clearly predefined a priori and constant, since substantially equal to the distance between the ring6and the free end of the tube.

It is therefore possible to size the tube in such a way that the protruding portion of the coupling1has the desired length, sufficient to enable a practical mating to the pump (or other devices), but not so long to determine a significant lever arm and therefore dangerous bending moments or torques, when in fact the user mates the pump to the valve101and/or to the second element3.

The use of two elements2,3therefore allows to achieve the intended object, since it is possible to control the length of the protruding portion of the coupling1(of the second element3) and of the assembly100, maintaining it sufficiently reduced so as to avoid dangerous stress and thus avoiding (or at least limiting) the risk of breakage or deformation.

The mating between coupling1(and/or assembly100) and pump has greater strength and greater resistance to transverse thrust, compared to known solutions.

It should also be noticed that the coupling1and the assembly100prove to be extremely versatile, since, as already observed, it is sufficient to make small changes to the second element3to allow its mating to caps and other structures of any shape and size, without having to completely change the components.

The pumps can also be any, dedicated or commercial, simply by varying the shape of the coupling1and in particular of the second element3and/or of the valve101.