Abstract:
A coupling assembly for connecting two tubular elements, in particular ends of two tubes of an air-conditioning system, includes two inter-engaging locking parts which, for the purpose of achieving a locked position, can be rotated with respect to one another and can be displaced with respect to one another in the axial direction. The locking parts utilize a bayonet locking feature and include at least two sub-elements, the sub-elements being fixed in the radial direction by two inter-engaging sleeves.

Description:
The invention relates to a coupling assembly connecting two tubular elements, in particular ends of two tubes of an air-conditioning system, having a bayonet lock in which the inter-engaged locking parts are rotated with respect to one another. 
     PRIOR ART 
     It is know, for example for the purpose of producing a coolant circuit, to connect individual tubes to one another at their ends. For this purpose, use is made of bayonet locks designed, for example, as quick-action couplings. The bayonet locks usually have two mutually associated, inter-engaging locking parts which, for the purpose of achieving a locked position, can be rotated with respect to one another and can be displaced with respect to one another in the axial direction. 
     The disadvantage with the known bayonet locks is that sealing is achieved exclusively via a radially shaped sealing element. In this case, said sealing elements are arranged, usually as sealing discs, between the two ends of the tubular elements. Such a quick-action coupling is unstable in relation to mechanical loading perpendicular to the axis of the two ends. 
     Furthermore, the sealing discs used each have two sealing surfaces, which butt against corresponding shaped sealing surfaces at the ends of the tubular elements. Said sealing surfaces are arranged in a manner radially offset with respect to the longitudinal center axis of the tubular elements, which is disadvantageous, in particular, if a pressurized medium is to be conveyed through the tubular elements. Furthermore, the size and the three-dimensional extent of the sealing surface is a measure of the pressure stability of such a seal; that is to say, the sealing surfaces are enlarged in the radial direction for the purpose of increasing this stability in the case of the known bayonet locks. The coupling is thus widened in the radial direction, and this results in a greater amount of space being required. 
     Also known are bayonet locks which, for the purpose of overcoming the above disadvantages of radial sealing elements, have axially shaped seals. For this purpose, usually one end of the tubular element is widened, in terms of its internal radius, to the external radius of the second tubular element. The two elements are then connected to one another axially. The two ends are thus designed as sealing elements, there inner or outer surface forming the sealing surface of the seal. This results, on the one hand, in an increase in stability of the bayonet lock in relation to transverse forces and, on the other hand, in an increase pressure stability as a result of the enlargement and the axial alignment of the sealing surface. The disadvantage is that, in the case of the known bayonet locks with an axial seal, specially formed tools are to be used, in part, for the purpose of releasing the connection. 
     It is also disadvantageous, in the case of the previously known bayonet locks, that, for fixing the coupling elements axially at the ends of the tubular elements, use is made of, in part, high-outlay arrangements, and that high outlay is involved for the purpose of fitting such a coupling element. 
     The object of the invention is to provide a coupling assembly of the generic type which is of straight forward design and in which it is possible to ensure good sealing action with low forces. 
     A coupling assembly having a bayonet-type locking feature is proposed in order to achieve this object. The coupling assembly has two locking parts each of which comprises two sub-elements. These sub-elements are fixed in the radial direction by two inter-engaging sleeves. It is possible to engage the lock at the ends of two tubular elements, and to remove the lock, without using an additional tool. Thus, it is possible to manually disassemble the coupling assembly. Since the locking parts each comprises a plurality of, preferably two sub-elements, the locking parts may also advantageously be subsequently fitted to, and removed from, a pipeline which has already been laid. In this case, the sub-elements of the locking parts are preferably configured such that they butt against one another in a planar manner and are fixed in position by the sleeves. 
     A development of the invention provides that the sleeves can be fixed in the axial direction by, in each case, one securing ring. A preferred embodiment provides that, when the locked position has been reached, this is indicated by a radial displacement of a moveable pin which is arranged in one of the inter-engaging sleeves. 
     A further preferred configuration of the invention provides that a first locking part comprises a sleeve into which a plug-in section of the second locking part can be latched. This achieves, in a straight forward manner, a positively and frictionally locking connection of the two locking parts to one another. 
     Furthermore, a preferred configuration of the invention provides that a sealing element is designed as an axial element which, when the components of the assembly are locked, is compressed in the axial direction. For this purpose, the sealing element preferably has shaped portions which can be displaced axially by the sealing surfaces without the latter being deflected radially in the process. The forces which are to be overcome by the axial compression of the shaped portions during transfer of the locking components into the locked position may be used simultaneously during unlocking of the bayonet lock, with the result that the forces which have to be applied from the outside for the purpose of releasing the assembly may be relatively low. As a result, it is also possible for the lock to be locked and unlocked without any additional tools. 
     Further advantageous configurations of the invention can be gathered from the rest of the features mentioned in the claims. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The invention is explained in more detail hereinbelow, by way of an exemplary embodiment, with reference to the drawings, in which: 
     FIG. 1 shows an exploded perspective view of an exemplary embodiment of the coupling assembly according to the invention; 
     FIG. 2 shows an elevational view, partly in section, of the coupling assembly according to FIG. 1 in an unlocked position with the components separated; 
     FIG. 3 shows an elevational view, partly in section, of the coupling assembly in a locked position; and 
     FIG. 4 a,  FIG. 4 b  and FIG. 4 c  show, in schematic perspective views, individual steps for reaching the locked position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 illustrates an exploded illustration of a coupling assembly  10  for connecting two tubular elements, namely, a first tube  12  and second tube  14 , each having end portions  16  and  18 , respectively, to be joined together. The tube end portion  16  has a first sealing surface  22 , which is formed by a flange  24 . In this case, the sealing surface  22  forms a radial annular surface. 
     The end portion  18  of the second tube  14  has a widened section  30 , which is designed such that an internal diameter of the widened section  30  is of essentially the same size as an external diameter of the end  16  of the tube  12 . This ensures that the end  16  of the first tube  12  can be displaced axially, or pushed, into widened section  30  of the second tube  14 . On its end side, the end  18  of the tube  14  has a disc-like flange  36  which forms an annular sealing surface  38 . The annular sealing surfaces  22  and  38  are thus located opposite one another at an axial distance apart and parallel to one another. 
     Also provided is a sealing element  34  of essentially annular design, the internal diameter of the sealing element  34  being approximately of the same size as the external diameter of the end  16  of the tube  12 . As a result, the sealing element  34  can be pushed onto the end  16 . Once the tube  14  has been plugged on, the sealing element  34  is thus positioned between the radial, annular sealing surfaces  22  and  38  and butts against said sealing surfaces  22 ,  38  or is clamped between said sealing surfaces  22 ,  38 . 
     The arrangement  10  further comprises a bayonet lock  40  which comprises two locking parts  42  and  44 . The locking part  42  comprises two sub-elements  46  and  48  which are each of approximately semi-circular design. Each of the sub-elements  46  and  48  has a planar contact surface  54  and  56 , these surfaces abutting against one another when they are subsequently positioned on the tubes  12  and  14 . For the purpose of fixing the two sub-elements  46  and  48 , use is made of a sleeve  92 , of which the internal diameter is of the same size as the external diameter of the first locking part  42 . For the purposes of the rest of the description, it is assumed that the locking part  42  forms a unit comprising the sub-elements  46  and  48 . 
     The locking part  42  has an axial through-opening  58 , of which the internal diameter corresponds to the external diameter of the tube  12 , the term “corresponds”, in the context of the present invention, being understood as meaning the same diameters. Furthermore, the locking part  42 , on the outside of the region which contains the axial through-opening  58 , has a tapered section  57  with radial depression  59 . The depression  59  can receive a securing ring  102 , which fixes the axial position of the sleeve  92 . For this purpose, the sleeve  92  has at one end  93 , on an inner surface  94 , a protrusion  100  which is preferably shaped radially. The protrusion  100  has an internal diameter which is smaller than the external diameter of the securing ring  102  and which corresponds to the external diameter of the tapered section  57 . This fixes the axial position of the sleeve  92  relative to the first locking part  42 . 
     The sleeve  92  also has a protrusion  91 , which extends out from the inner surface  94 , parallel to the axis of the tube  12 , and has a groove or shoulder  89 . The protrusion  91  has an inner surface  87  which is configured such that it is located on a lateral surface  61  of the locking part  42  in a positively locking manner and thus prevents radial rotation of the sleeve  92  and the locking part  42 . The lateral surface  61  also has a groove or shoulder  63  on which, once the bayonet lock  40  has been fitted, the groove/shoulder  89  of the sleeve  92  is located, with the result that the sleeve  92  is arranged in a defined position in relation to the locking part  42 . 
     The locking part  42  further comprises a sleeve  60  with a sleeve inner surface  62 . Radially inwardly directed protrusions  64  are arranged on the sleeve inner surface  62 . The sleeve  60  forms, in practice, an interior of the bayonet lock  40 . 
     The locking part  44  likewise comprises two essentially semi-circular sub-elements  50  and  52 . Each of the sub-elements  50  and  52  has two planar contact surfaces  68  and  70 , which abut against one another when the locking part  44  is placed in position. It is thus also possible for the locking part  44  to be subsequently placed in position on the tube  14 . The locking part  44  is fixed in the radial direction by a sleeve  104 . The sleeve  104  has an internal diameter which corresponds to the external diameter of the locking part  44 . The sleeve  104  also has a lateral surface  106 , of which the diameter corresponds to the internal diameter of the first sleeve inner surface  94 . 
     The locking part  44  has a through-opening  76 , of which the internal diameter corresponds essentially to the external diameter of the widened section  30  of the tube  14 . The locking part  44  can thus be moved axially in relation to the widened section  30  and the flange  36 . 
     Furthermore, at its end  73 , the locking part  44  has a tapered section  74  with a radial depression  75 . In this case, the depression  75  may, again, receive a securing ring  102 , of which the external diameter, again, is greater than the internal diameter of a protrusion  108  which extends radially inwards at the end  105  of the second sleeve  104 . The internal diameter in the region of the sleeve  104  which has the protrusion  108  corresponds to the external diameter of the tapered section  74  of the locking part  44 . This fixes the sleeve  104  in the axial direction. 
     The sleeve  104  also has a protrusion  110 , which extends out from an inner surface  112 , parallel to the axis of the tube  14 . The protrusion  110  has an inner surface  114  which is designed such that it is located on a lateral surface  53  of the locking part  44  in a positively locking manner and thus prevents radial rotation of the sleeve  104  and of the locking part  44 . 
     Furthermore, in the region of a plug-in section  77 , the sub-element  50  of the locking part  44  has a depression  78 , of which the lateral surface  80  corresponds to the internal diameter of the protrusion  64  of the first locking part  42 . 
     In the region of the plug-in section  77 , the sub-element  52  has a radially running annular surface  82 . The annular surface  82  has a first section  84 , which runs parallel in relation to the sealing surfaces  22  and  38  and passes into a second section  86 , which runs conically or obliquely in relation to the sealing surfaces  22  and  38 , at an angle to a plane perpendicular to the axis of the tubes  12  and  14 . Finally, the section  86  is followed by an again parallel section  88 , which terminates at an axially running, stop-forming protrusion  90 . 
     The overall axial length of the plug-in section  77  is such that, when it is plugged into the sleeve  60  of the locking part  42 , it can engage behind the protrusions  64  by way of its annular surface  82 . The internal diameter of the plug-in section  77  is selected to be greater than the external diameter of the flanges  24  and  36 . 
     The first sleeve  92  also has at least one bore  95 , in which there is arranged a radially displaceable pin  96  which serves as an indicator element. On its radially inwardly arranged side, the pin  96  has a rounded section  98 . In the unlocked position, the rounded section  98  projects beyond the inner surface  94  of the sleeve  92 . 
     FIG. 2 shows the coupling assembly  10 , in a partially sectioned illustration, in an unlocked position, while FIG. 3 shows the coupling assembly  10  in a locked position. The same parts as in FIG. 1 are provided with the same designations, so they will not be explained again. 
     FIG. 2 shows clearly that, in the unlocked state, the pin  96  is displaced radically inwards to such an extent that it does not project beyond the outer surface of the sleeve  92 . The pin  96  has thus been fully retracted into the bore  95 . 
     In the locked position, which is shown in FIG. 3, the end  16  of the tube  12  engages in the widened section  30  of the tube  14 . At the same time, the plug-in section  77  of the locking part  44  engages in the sleeve  60  of the locking part  42 . With reference to the steps which are explained in even greater detail with reference to FIGS. 4 a  to  4   c,  the locking parts  42  and  44  are rotated with respect to one another during transfer from the unlocked position, according to FIG. 2, into the locked position according to FIG. 3, in which case said locking parts simultaneously advance towards one another in the axial direction. The axial advancement of the locking parts  42  and  44  is designed by the progression of the annular surface  82 . When the plug-in section  77  is plugged into the sleeve  60 , the protrusions  64  engage in the region of the depression  78  of the plug-in section  77 . Upon rotation of the locking part  44 , the protrusion  64  then abuts against the annular surface  82 . 
     The locking parts  42  and  44  are rotated with respect to one another until such time as the protrusion  64  can be guided along the annular surface  82 . This achieves the situation where the locking parts  42  and  44  are moved towards one another in the axial direction in the conically running section  86 . The definitive locked position is then reached when the protrusion  64  abuts against the protrusion  90 . In the locked position, the sleeve  104  likewise engages in the sleeve  92 . In the axial advancement of the locking parts  42  and  44  towards one another during rotation, the sleeve  104  reaches that region of the sleeve  92  in which the pin  96  is arranged. As rotation of the locking parts  42  and  44  with respect to one another continues, during which time the rounded section  98  of the pin  96  slides along the ramp  72 , the pin  96  is displaced radially outwards, with the result that it projects beyond the outer surface/lateral surface  101  of the sleeve  92 . The pin  96  thus serves for indicating the locked position of the coupling assembly  10 . If this locked position is correct, it is possible to feel or to see the pin  96 . 
     While the locking parts  42  and  44  move towards one another in the axial direction, and thus the flanges  24  and  36  advance towards one another, the sealing element  34  comes into abutment with the sealing surfaces  22  and  38 . 
     FIGS. 4 a  to  4   c  show graphically once again the guidance of the coupling assembly  10 , that is to say the locking parts  42 ,  44  from the unlocked position to the locked position. FIG. 4 a  is the unlocked position with the locking part  42  arranged on the end  16  of the tube  12  and the locking part  44  arranged on the end  18  of the tube  14 . 
     In accordance with FIG. 4 b,  the locking part  44  is introduced into the sleeve  60  of the locking part  42  by way of its plug-in section  77 . At the same time, the end  16  of the tube  12  passes into the widened section  30  of the tube  14  and the sleeve  104  passes into the sleeve  92 . The locking part  44  is pushed into the locking part  42  in a defined position, in which the protrusion  64  can engage in the depression  78  and be pushed through in the axial direction there. Once the protrusion  64  has moved axially along the lateral surface  80  of the depression until it is level with the annular surface  82 , the locking parts  42  and  44  are rotated with respect to one another. In this case, the protrusion  64  is guided along the annular surface  82 , with the result that—as has already been explained—axial movement additionally takes place at the section  86 . During rotation of the locking parts  42 ,  44  with respect to one another, the rounded section  98  of the pin  96  slides on the ramp  72  and is thus pushed radially outwards through the bore  95 . The section  88  of the annular surface  82 , in turn, runs parallel to the rotary movement (i.e. parallel to a plane perpendicular to the axis of the tubes  12  and  14 ), with the result that there is no more axial movement. The protrusion  64  is guided as far as the protrusion  90  and abuts against the latter without stressing. Rotation of the locking parts  42  and  44  with respect to one another in the opposite direction, and thus unlocking of the coupling assembly  10 , can take place if the protrusion  64  is guided into the region of the conically running section  86  again. Since the sealing element  34  usually consists of an elastic material which is compressed/pressed together in the axial direction during locking, it is thus possible to provide a restoring force for the unlocking operation. The operation of unlocking the assembly is thus assisted in the region of the conically running section  86 , with the result that there is no need for any additional tools.