Abstract:
A fitting has an external body and a caliper element, lodged in an axial cavity of the body and able to block the end of a tube inside the cavity. The caliper element can be moved from a rearward position blocking the tube, to a forward position releasing the tube, and includes a flanged rim protruding from an end of the body. A security ring is joined to the end of the body from which the flanged rim protrudes. The ring has an outer portion which extend axially from the end and can resist at least an axial force exerted manually, and an innermost portion which is flexible so that when subjected to an axial force exerted manually, it can move axially and to touch the flanged rim. The inner and outer portions are reciprocally positioned so pressure can be exerted on the innermost portion only with a special tool.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a fitting for a tube, especially for braking systems. 
       BACKGROUND OF THE INVENTION 
       [0002]    Fittings for tubes according to the preamble of claim  1  are already known of. Such fittings are known as rapid or super rapid fittings. 
         [0003]    In the braking system sector, especially for heavy vehicles, for reasons of safety, tubes which cannot be extracted from a connection except by an authorised person, are required. As a result, such fittings have a component which blocks the tube that, rather than being possible to manoeuvre by hand as in traditional fittings, is a specific element that can only be manoeuvred through use of a specific tool available to authorised staff. 
       SUMMARY OF THE INVENTION 
       [0004]    The purpose of the present invention is to propose a fitting making it possible to satisfy such requisite of improved security but which, at the same time, uses traditional components. 
         [0005]    Such purpose is achieved by a fitting comprising an external body and a caliper element lodged in an axial cavity of said body and able to block the end of the tube inside said cavity. The caliper element can be shifted from a rearward position blocking the tube to a forward position releasing the tube, and comprises a flanged rim on which the axial force used to shift the caliper into said forwarded release position can be exerted. The flanged rim of the caliper is surrounded by an external security ring portion able to resist at least any axial force exerted manually, said external ring portion being positioned in such a way as to allow access to the flanged rim only by means of a special tool. 
         [0006]    In accordance with a particularly advantageous embodiment, the external security ring portion terminates in a narrowed protecting portion, axially distant from and aligned with the flanged rim of the caliper element. Such protecting portion is flexibly yielding if subjected to said axial force exerted manually, so as to be able to be shifted axially into contact with said flanged rim. The external and protecting portions are reciprocally positioned so as to make pressure solely on the innermost portion possible only by use of the special tool. 
         [0007]    The external security ring portion which surrounds the flanged rim of the caliper element thus prevents access to the latter, except by means of a special tool of such thickness as to engage the flanged rim only, but not the external ring portion. The protecting portion makes it possible to prevent, at the moment of insertion of the tube in fitting, the passage of foreign bodies such as dirt, dust or oil, inside the fitting. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Further features and advantages of the fitting according to the present invention will be evident from the description below, made by way of an indicative and non-limiting example of its preferred embodiments, with reference to the attached figures wherein: 
           [0009]      FIG. 1  shows an exploded view of a fitting according to the invention, in a first embodiment; 
           [0010]      FIG. 2  shows the same exploded view, but in an axial cross-section; 
           [0011]      FIG. 3  shows the assembled fitting in partial axial cross-section; 
           [0012]      FIG. 4  shows, in cross-section, the fitting with a tube inserted and a manoeuvring tool in an idle position; 
           [0013]      FIG. 4   a  shows an enlarged detail of  FIG. 4 ; 
           [0014]      FIG. 5  shows, in cross-section, the fitting with a tube inserted and the manoeuvring tool in an active position releasing the tube; 
           [0015]      FIG. 6  shows an exploded view of a fitting according to the invention, in an embodiment variation; 
           [0016]      FIG. 7  shows the same exploded view but in axial cross-section; 
           [0017]      FIG. 8  shows in partial axial cross-section, the assembled fitting; 
           [0018]      FIG. 9  shows, in cross-section, the fitting with a tube inserted and the manoeuvring tool in an idle position; and 
           [0019]      FIG. 10  shows, in cross-section, the fitting with a tube inserted and the manoeuvring tool in an active position releasing the tube. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    With reference to  FIGS. 1-5 , reference numeral globally denotes a rapid fitting according to the invention in a first embodiment. The fitting  1  is able to fluidically connect a tube  2  to a fluid collection body—not shown. 
         [0021]    The fitting  1  comprises an external body  10  which extends axially from an inlet portion  13 , which the tube  2  is inserted into, to an outlet portion  14 , suitable for joining to the fluid collector body. To form such coupling, the outlet portion  14  has, for example, a threaded portion  15 . 
         [0022]    The body  10  defines internally an axial cavity  12 . 
         [0023]    In the body  10 , a first annular shoulder  16  is formed which a sealing element, such as an o-ring  18  rests on. 
         [0024]    According to one embodiment, a second annular shoulder  20  is formed inside the body  10  which a guide sleeve  22  for the end of the tube  2  inserted in the fitting  1  rests on, on the opposite side to that on which it is attached to the collector body. 
         [0025]    A caliper element  24  is seated in the body  10  for blocking the end of the tube  2  in the fitting  1 . 
         [0026]    The caliper element  24  is comprises an essentially cylindrical body  25  at the end of which a number of biting teeth  26  are provided, individuated by notches  27  directed according to the generators of the cylindrical body. Each of said teeth  26  has a conical external surface  26 ′ which tends to widen radially towards the end, and pointed portions  28  facing inwards radially, able to interact with the external surface of the tube  2 . Each tooth  26  terminates moreover in a countersunk surface at the end  29  able to interact with the sealing element  18 , as will be explained better below. 
         [0027]    On the side opposite the teeth  26 , the body  25  of the caliper element terminates in a flanged rim  30  which protrudes from the inlet portion  13  of the body  10 . 
         [0028]    Internally, the body  10  of the fitting  1  also has an annular projection  32  protruding radially inwards and able to interact with the external conical surface  26 ′ of the teeth  26 , when the element is in the blocked position, as will be illustrated below. 
         [0029]    Normally, or following the insertion of the end of the tube  2  in the caliper element, the latter finds itself in an idle position, in which the biting teeth  26  are found beyond the annular ridge  32  (in relation to the direction of insertion of the tube) of the body  10 . The tube, advancing in the caliper element  24 , widens the teeth  26  and hits against the rim of the guide sleeve  22  resting on the second shoulder  20 . 
         [0030]    Simple pulling of the tube backwards and/or the onset of the pressure of the fluid inside the fitting provokes a backward movement of the tube  2  and therefore an interaction of the pointed portions  28  of the teeth  26  with the surface of the tube. The caliper element  24  too tends therefore to move backwards, until the annular projection ridge  32  in the body  10  engages the external surface  26 ′ of the teeth  26 , pushing them radially and forcing them to bite the tube more strongly. In this position, the tube  2  remains firmly inserted in the fitting. 
         [0031]    The fitting  1  also comprises a security ring  40  fitted onto the body  10  of the fitting. 
         [0032]    The security ring  40  comprises a cylindrical portion  42  fitted onto the body  10 , near the input end  13  and extending axially from such end of the body  10 . Said cylindrical portion  42  therefore has a bigger internal diameter than that of the tube  2 , for example equal to the external diameter of the flanged rim  30  of the caliper element  24 . 
         [0033]    The security ring  40  terminates, on the part opposite the body  10 , narrowing into an annular protecting portion  44  able to embrace, making contact with the same, the outer surface of the tube  2 . In other words, the internal diameter of said annular portion is equal to the external diameter of the tube  2 . Consequently, the annular portion  44  is essentially axially aligned to the flanged rim  30  of the caliper element  24 . 
         [0034]    The cylindrical portion  42  and the annular portion  44  are joined by an intermediate portion  46 . Preferably, such intermediate portion  46  extends in a radial direction, that is perpendicularly to the main axis of the fitting  1 . 
         [0035]    Advantageously, moreover, the annular portion  44  terminates with an inner countersunk surface  44 ′, so as to facilitate the insertion of the tube  2  into the security ring. 
         [0036]    The cylindrical portion  42  of the ring  40  has the characteristic of not being deformable axially if subjected to an axial force exerted with a person&#39;s hand. Such function may be obtained by choosing a suitable material and/or appropriate thickness for the cylindrical portion  42 . 
         [0037]    In addition, advantageously, the resistance to axial deformation of the cylindrical portion  42  is further accentuated by the fact that it rests, at least in part of its transversal cross-section, on the annular rim  13 ′ defining the inlet of the body  10 . 
         [0038]    The intermediate portion  46 , rather, has the characteristic of being flexibly yielding if subjected to such axial force. In other words, an axial force, exerted that is to say along the main axis of the fitting, applied to the intermediate portion  46  and/or the annular portion  44 , causes the bending of such intermediate portion  46  as a result bringing the annular portion  44  closer to the flanged rim  30  of the caliper element  24 . 
         [0039]    Upon cessation of the axial pressure, the intermediate portion  46  and thus the annular portion  44  connected to it return to their original position. 
         [0040]    Such elastic yielding function may be absolved by choosing a suitable material and/or reduced thickness for the intermediate portion  46 . 
         [0041]    It should be noted that the radial extension of the intermediate portion  46  and of the annular portion  44  is such that once the tube has been inserted in the fitting  1  through the security ring  40 , it is not possible to press the intermediate portion and/or annular portion  44  with the fingers without acting on the cylindrical portion  42  too. The result is that the intermediate portion  46  cannot be bent axially and consequently nor can the annular portion  44  be made to advance axially towards the caliper element  24 . 
         [0042]    By acting rather with a “localised” pressure on the intermediate portion  46  and/or the annular portion  44  only, with the same force applied one can achieve such axial shifting of the annular portion  44 . 
         [0043]    The length or axial extension of the security ring  40  is chosen so that the axial shift of the annular portion  44  which can be obtained by operating in a manual but localised manner makes it possible to bring said annular portion  44  into contact with the flanged rim  30  of the caliper element, so as to transmit the pressure exerted to the latter. 
         [0044]    For the realisation of the security ring  40  advantageously a polymer, natural or synthetic shape memory material may be used at least for the intermediate and annular 44 portions. The different rigidity between the cylindrical portion and the intermediate portion may be obtained by a different cross-linking of the polymer and/or by giving different thicknesses to the two parts, as shown in the example illustrated. 
         [0045]    According to an embodiment variation of the fitting  100  illustrated in  FIGS. 6-10 , wherein the elements of the fitting common to the first embodiment have been indicated with the same reference numerals, the flanged rim  30  of the caliper element  24  is surrounded by an external annular security portion  420  obtained as an extension of the inlet portion  13  of the body  10  of the fitting which terminates at least at the height of the flanged rim  30 , preferably beyond said rim, as in the example shown. Once a tube  2  has been inserted in the fitting, such external annular portion  420  prevents access to the flanged rim  30  with the fingers, making the use of tool specially designed for releasing the tube necessary. 
         [0046]    Advantageously, at the inlet portion  13  of the body which surrounds the flanged rim  30  of the caliper element a protective cap  421  is fitted which comprises an external cylindrical portion  422 , which envelops said inlet portion  13 , and which terminates narrowing to an annular portion of protecting  440  axially distanced from and aligned with the flanged rim  30 . Such annular protecting portion  440  is able to embrace the outer surface of the tube  2 , being in contact with it when inserted in the fitting. Advantageously, moreover, the annular protecting portion  440  terminates with a countersunk inner surface  440 ′, so as to facilitate insertion of the tube  2 . 
         [0047]    The annular protecting portion  440  is joined to the external cylindrical portion  422  by an intermediate portion  460 . Preferably, such intermediate portion  460  extends in a radial direction, that is, perpendicularly to the main axis of the fitting  100 . 
         [0048]    The intermediate portion  460 , rather, has the characteristic of being flexibly yielding if subjected to axial force exerted manually. In other words, an axial force, exerted that is to say along the main axis of the fitting, applied to the intermediate portion  460  and/or the annular portion  440 , causes the bending of such intermediate portion  460  as a result bringing the annular portion  440  closer to flanged rim  30  of the caliper element  24 . ( FIG. 10 ). 
         [0049]    Upon cessation of the axial pressure, the intermediate portion  460  and thus the annular portion  440  connected to it return to their original position. 
         [0050]    Such elastic yielding function may be absolved by choosing a suitable material and/or reduced thickness for the intermediate portion  460 . 
         [0051]    In this case too, the radial extension of the intermediate portion  460  and of the annular portion  440  is such that, once the tube  2  has been inserted in the fitting  1 , it is not possible to press the intermediate portion  460  and/or the annular portion  440  with the fingers without also acting on the cylindrical extension  420  of the end  13  of the body  10 . 
         [0052]    In other words, the embodiment variation of the fitting illustrated in  FIGS. 6-10  differs from the form of embodiment shown in  FIGS. 1-5  by the fact that the cylindrical portion  42  of the security ring  40  is replaced by the extension  420  of the inlet portion  13  of the body  10 . In the embodiment variation, therefore, the cylindrical portion  422  of the protective cap  421  has the main function of coupling to the body  10  and acting as a support to the yielding portion  460  and the annular protecting portion  440 . 
         [0053]    According to one embodiment, near the inlet portion  13 , the body  10  is fitted on its outer surface with a cuneiform annular tooth  50  able to facilitate the application of the security ring  40  or protective cap  421  to the body  10  and to prevent accidental slipping off. 
         [0054]    The present invention also relates to a tool  60  able to exert localised pressure on the annular protecting portion  44 ;  440  of the security ring or protective cap respectively. 
         [0055]    According to one embodiment, such tool  60  can be rapidly coupled to the tube  2 . For example the tool  60  has a “C”-shaped transversal cross-section so as to be geometrically and firmly coupled to the tube  2 . 
         [0056]    The tool  60  comprises a flanged portion head  61 , able to be engaged manually by an operator, and a collar  62  extending from said head portion  61  and which, when the tool  60  is joined to the tube  2 , adheres to it and faces the fitting. 
         [0057]    The collar  62  is of a thickness more or less equal to that of the annular protecting portion  44 ;  440 , so that however much the tool is pressed into contact with said ring the collar acts solely on the internal annular portion  44 ;  440 , or at most also on the intermediate portion  46 ;  460 . 
         [0058]    The tool  60  therefore acts as an adaptor or reducer element to concentrate the force exerted by the operator on the head portion  60  of a circumference, or in any case on an annular surface of a thickness essentially equal to that of the annular portion  44 ;  440 . 
         [0059]      FIGS. 4 ,  9  show the fitting  1  with the tool  60  connected to the tube  2  but in a distanced position from the annular protecting portion  44 ;  440 . 
         [0060]      FIGS. 5 ,  10  show the tool  60  in pressure on the annular portion  44 ;  440 . As anticipated above, in this condition an operator is able, with the tool  60 , to act on the annular portion  44 ;  440  and therefore on the flanged rim  30  of the caliper element  24 , pushing it into a forward position in which the tube is released. In such forward position, the biting teeth  26  disengage from the annular ridge  32  and, thanks also to the cone-shaped surface of the end  29  of said teeth and the sealing element  18 , distanced sufficiently to enable the disengagement of the pointed portions  28  from the surface of the tube  2 , and therefore the extraction of the same from the fitting. 
         [0061]    It should be noted that this operation requires a force exerted by the operator similar to the force that direct action on the caliper element of a traditional fitting would require. 
         [0062]    Advantageously, the security ring  40  can be fitted onto a fitting  1  having a body  10  and a caliper element  24  of the known type. In other words, this application does not require the supplier of couplings to produce and deal in specific fittings. 
         [0063]    A further, non-secondary aspect of the fitting which the present invention relates to is that the annular protecting portions  44 ,  440  of the security ring  40  and protective cap  421  perform an important function of protecting the fitting from dirt, dust or other agents which might get into it. 
         [0064]    In fact, if the tube  2  is not clean, when it is inserted in the security ring  40  or in the protective cap  421  the outer surface of the end which goes into the fitting is cleaned by contact with the annular portion  44 ;  440  of the security ring or protective cap. 
         [0065]    A man skilled in the may make modifications, adjustments and replacements of elements with others functionally equivalent to the fitting described above so as to satisfy contingent requirements, while remaining within the scope of the following claims. Each of the characteristics described as belonging to a possible embodiment may be realised independently of the other embodiments described.