Patent Publication Number: US-2023135793-A1

Title: Fluid line coupling

Description:
The invention relates to a reversibly detachable fluid line coupling, at least having a coupling sleeve, a locking element and a coupling plug with a locking collar. 
     Fluid line couplings of the stated type are used in multiple applications. One important field of application is automotive engineering. There, use is often made of SAE couplings, that is to say couplings with standardized plug geometries. 
     Such couplings can be plugged into one another and latched relatively securely because of the large guide length of the plug. With this type of coupling, however, it can be difficult to see whether the coupling plug is also correctly latched in the coupling sleeve. Although secure latching can be checked mechanically, this means an increased effort during assembly and is not easy to automate either. US 2017/0363237 A1 discloses such a coupling. 
     In addition, generic couplings are also known which have an optical latching indicator such that the correct fit of the coupling plug is visible. US 2016/0201835 A1 shows such a coupling. Here, however, two locking elements are necessary, which have to engage in one another, which can lead to a tilting of the elements in the event of an axial load that occurs when the coupling plug is inserted, and therefore latching is not achieved. While such a failure is visible in the disclosed embodiment, it is not desired. 
     US 2010/0276924 A1 also discloses a fluid line coupling with a display of the locking state. Although the subject matter of this document has a visual display in the form of an element protruding from the coupling, this only signals whether the locking has been actuated. Manual reworking is necessary here in any case. 
     The invention was based on the object of creating a fluid line coupling of the type described at the outset, the latching state of which can easily be checked automatically, with a visual check being preferred. 
     This object is achieved in that: 
     the coupling sleeve has a collar which faces axially outward from a first opening provided for the insertion of the coupling connector and is spaced apart from the insertion opening, 
     the coupling sleeve has a predetermined number of openings in its outer wall, and 
     the locking element is arranged axially displaceably inside the coupling sleeve and has a number of resilient locking arms that corresponds to the number of openings in the coupling sleeve, 
     the locking arms being distributed on the circumference of the locking element and extending in the axial direction and having actuating/signaling surfaces facing radially outward at their axial ends, and 
     the actuating/signaling surfaces correspond in shape and position to the openings in the coupling sleeve and protrude resiliently through the openings in the coupling sleeve radially outward from the coupling sleeve, 
     the fluid line coupling has a blocking ring enclosing the coupling sleeve, the blocking ring having a base part, a spring part and a blocking part, and the base part and blocking part being resiliently variably spaced apart in the axial direction by means of the spring part, and 
     the blocking ring has an inner diameter that can be slid over the outer circumference of the coupling sleeve with little play, 
     the play between the coupling sleeve and the blocking part being dimensioned in such a way that the blocking part cannot be slid over the actuating/signaling surfaces protruding from the openings in the coupling sleeve, 
     the actuating/signaling surfaces have a different color from the blocking part of the blocking ring, 
     the blocking ring being arranged in the preassembled state on the coupling sleeve in such a way that the base part is supported on the support collar of the coupling sleeve, the blocking part is supported against the actuating/signaling surfaces protruding from the openings in the coupling sleeve, and the spring part is pushed together axially, as a result of which an axial spring force is effective between the base part and blocking part, and, 
     when the coupling connector is pushed in and locked, the actuating/signaling surfaces are displaced in the direction of the interior of the coupling sleeve to such an extent that they no longer protrude from the openings in the coupling sleeve, but are still prevented from sliding out of the coupling sleeve axially by the wall of the coupling sleeve, and therefore the blocking part of the blocking ring is released and is displaced beyond the actuating/signaling surfaces in the direction of the push-in opening by the spring force of the spring part of the blocking ring such that the actuating/signaling surfaces are no longer visible and are also no longer displaceable radially outward from the openings in the coupling sleeve. 
     An arrangement of this type makes it possible to optically signal the locking state of a coupling of the type in question. Only when the coupling is locked are the actuating/signaling surfaces displaced in the direction of the interior of the coupling sleeve and only then can the blocking part slide over the actuating/signaling surfaces. Since the actuating/signaling surfaces have a different color, this change can be easily detected with a camera, even from any viewing angles. This check can thus be fully automated. 
     In a development of the invention, the transition from the locking arms to the radially outwardly directed actuating/signaling surfaces at least partially has a slope. 
     With an axial displacement of the blocking ring in the coupling sleeve in the direction away from the insertion opening, the transition regions slide over the edges of the openings in the coupling sleeve. The smooth transition ensures that the locking arms are pressed into the interior of the coupling sleeve during said movement, with the actuating/signaling surfaces also being pulled inward. 
     In one development of the invention, the locking arms have radially inwardly facing blocking lugs at their axial ends opposite the actuating/signaling surfaces. 
     The blocking lugs engage upon an axial displacement of the locking element and associated displacement of the ends of the locking arms inward over the blocking collar of the coupling connector. Since the actuating/signaling surfaces are still supported axially on the wall of the coupling sleeve, the assembly of locking element and coupling plug can no longer be pulled out of the coupling sleeve. Only when the blocking part of the blocking ring is manually pushed back is it possible for the locking arms to spring apart again such that the coupling is detachable again. 
     In a development of the invention, a predetermined number of locking arms have insertion aids in the form of bevels arranged in the axial direction on their blocking lugs, and said blocking lugs protrude radially into the interior of the coupling sleeve to such an extent that, when the coupling connector is pushed in, the locking collar butts against the bevels and therefore the blocking lugs are displaceable radially outward. 
     Since, when a coupling connector is pushed in, the actuating/signaling surfaces have to be displaced outward in this way, this is thus not possible if the blocking part of the blocking ring is in an incorrect starting position so that the coupling connector cannot be pushed into the coupling sleeve. This ensures that the incorrect starting position of the blocking part is not misinterpreted as a correctly locked coupling. 
     In a development of the invention, the locking arms not having insertion aids at the radial ends of their blocking lugs each have a guide web which extends in the axial direction. 
     The guide webs ensure that the coupling connector is introduced rectilinearly, so that it does not tilt when it is inserted. 
     In a development of the invention, the locking element has axially aligned longitudinal stops in the interior. 
     The driver webs are used to reliably displace the locking element, when the coupling plug is inserted in the axial direction, from the insertion opening in the coupling sleeve into the coupling sleeve in order to reliably ensure that the actuating/signaling surfaces are pulled in. The locking collar butts against the driver webs and thereby pushes the locking element in front of it into the coupling sleeve. 
     In a development of the invention, the locking arms having guide webs each have blocking lugs pointing axially in the direction of the insertion opening in the coupling and spaced radially from the guide webs, the distance between the respective guide web and blocking lug being dimensioned such that the wall of the coupling sleeve can engage in the region of the openings between the guide web and the blocking lug. 
     The blocking lugs prevent the engaging locking arms from not accidentally being able to be pressed slightly into the interior of the coupling housing, when the coupling connector is displaced, in order to avoid the blocking ring sliding over the signaling surfaces although no coupling connector is inserted. 
     In a development of the invention, all the components of the fluid line coupling are formed from plastic. 
     The components of a fluid line coupling according to the invention can be easily produced, for example, by injection molding. Plastic has good spring properties and can easily be colored. 
    
    
     
       An exemplary embodiment of the invention will be discussed in more detail below on the basis of the drawing. 
         FIG.  1    illustrates a fluid line coupling  1  according to the invention in a section. The coupling  1  has a coupling sleeve  2 , a locking element  3 , a coupling connector  4 , a blocking ring  5  and two seals  6 . Furthermore, the coupling has an insertion opening  11  which is provided for inserting the coupling connector. The O-ring seals  6  ensure a secure seal between the coupling sleeve  2  and the coupling connector  4  when the coupling connector  4  is inserted. In this illustration, the coupling connector  4  is inserted into the coupling sleeve, but not locked. The coupling connector  4  has a blocking collar  41 . 
     
    
    
     The individual parts of the coupling  1  will be explained in more detail below. 
     In  FIG.  2   , the coupling sleeve  2  is shown by itself in a perspective view. The coupling sleeve has a wall  22  with four openings  23 . A connection region  24  for connection to a further fluid line, not shown here, is arranged on the coupling sleeve  2  opposite the insertion opening  11 . In the present example, the connection region  24  is angled by 90°, but may be oriented in all conceivable positions. A stop collar  25  facing radially outward is arranged at the end of the coupling sleeve  3  assigned to the connection region  24 . 
     In  FIG.  3   , the locking element  3  is shown by itself. The locking element  3  has four locking arms  31 . The locking arms  31  are aligned axially in such a way that their ends  311  face in the direction of the insertion opening, not shown here, of the coupling sleeve. An actuating/signaling surface  312  which is directed radially outward and differs in color from the other components is arranged in each case at each end  311  of the locking arms  31 . Either a blocking lug  313  or  314  which protrudes radially inward into the locking element  3  is in each case arranged radially opposite the actuating/signaling surfaces  312 . The blocking lugs  313 , which are each in pairs, protrude further inward than the blocking lugs  314 , which are also in pairs. An axially aligned guide web  3142  is arranged on the blocking lugs  314  at their inner ends  3141  in each case. In addition, the blocking lugs  314  each have a blocking web  3144  on their axial end faces  3143 . 
     The blocking lugs  314  prevent the engaging locking arms  31  from not accidentally being able to be pressed slightly into the interior of the coupling housing  2 , when the coupling connector  4  is displaced, in order to avoid the blocking ring  5  sliding over the signaling surfaces  312  although no coupling connector  4  is inserted. 
     The blocking lugs  313  have inwardly directed bevels  3132  on their axial end surfaces  3131 . These serve as an insertion aid for the coupling connector, which is not shown here. 
     The locking arms  31  have an inclined transition surface  3121  in the transition from the arm to the respective actuating/signaling surface  312 . 
       FIG.  4    shows the assembly of the coupling sleeve  2  and the locking element  3 . The locking element  3  is inserted into the interior of the coupling sleeve  2 , which is possible by elastic compression of the locking arms  31 . The compression is facilitated by the inclined transition surfaces  3121  which slide over the edge of the insertion opening  11  when the locking element  2  is pushed in and press the locking arms inward. 
     In the position shown, the actuating/signaling surfaces  312  protrude through the openings  23  in the coupling sleeve since the locking arms  31  have sprung back outward into their starting position. 
     In  FIG.  5   , the blocking ring  5  is shown by itself in its starting position. The blocking ring has a base part  51 , a spring part  52  and a blocking part  53 , with the base part  51  and blocking part  53  being spaced apart resiliently variably in the axial direction by means of the spring part  52 . 
       FIG.  6    shows the fluid line coupling  1  according to the invention in the state as it is also shown in  FIG.  1   , as a longitudinal section. 
     The blocking ring  5  is slipped over the coupling sleeve  3  and the actuating/signaling surfaces  312 , with the actuating/signaling surfaces  312  being able to spring inward when pushed on. This step is possible only if the coupling connector is not inserted. The base part  51  is now supported against the stop collar  25  of the coupling sleeve  2 . When the blocking ring  5  is pushed on, the blocking part  53  can be pushed together in the direction of the base part  51  of the blocking ring  5  such that, in the position shown, the actuating/signaling surfaces  312  are again in their starting position. The blocking part  53  of the blocking ring  5  is now supported axially against the actuating/signaling surfaces  312  protruding outward through the openings  23  in the coupling sleeve  2 , and therefore it cannot slide axially over the actuating/signaling surfaces  312 . The coupling connector  4  is inserted but not yet locked and protrudes axially into the interior of the coupling sleeve through the seals  6 . It is guided radially by the blocking collar  41  and the guide webs  3142  of the blocking lugs  314 . Owing to the fact that the blocking lugs  314  do not protrude so far into the interior of the coupling sleeve, the blocking collar  41  fits between the guide webs  3142  with little play. 
       FIG.  7    shows the same state of the fluid line coupling  1  as in  FIG.  6   . While the blocking collar  41  of the coupling connector  4  slides past the guide webs  3142 , it butts against the bevels  3132 . As a result, the locking webs  31  concerned can be pushed further outward through the openings  23  in the coupling sleeve  2 . 
     As it is pushed in further, a state that is shown in  FIG.  8    is established. The blocking collar  41  now butts against stops  32  of the locking element  3  and pushes the latter axially in front of it. The sloping transition surfaces  3121  are positively guided over the edges of the openings  23  and are displaceable inward as a result. 
       FIG.  9    shows the locked state of the fluid line coupling  1 . The blocking lugs  313  and  314  now reach behind the blocking collar  41  into the interior of the coupling sleeve  3  to such an extent that the coupling connector  4  is locked. At the same time, the blocking part  53  is pushed over the actuating/signaling surfaces  312  by the spring part  52 . As a result, it is no longer possible to displace said surfaces outward. The coupling  1  is now firmly locked. 
     When the coupling  1  is loaded by fluid pressure, the coupling connector is displaceable a small distance in the direction of the insertion opening  11 . The locking element  3  is supported on the edges of the openings  23  facing the insertion opening  11  on the coupling sleeve  3 , and therefore the coupling connector  4  can no longer slide out. 
     Owing to the fact that the actuating/signaling surfaces  312  of different color are covered by the blocking part  53 , an optical check, in particular with a camera, is possible. 
     To detach the coupling, the blocking part  53  is displaceable manually in the direction of the base part  51 . The actuating/signaling surfaces  312  are thereby releasable and the locking arms displaceable outward. The coupling  1  is detachable again by pulling on the coupling connector  4 . 
     LIST OF REFERENCE SIGNS 
     Part of the Description 
     
         
           1  Fluid line coupling, coupling 
           11  Insertion opening in the coupling  1   
           2  Coupling sleeve 
           21  O-ring seals 
           22  Wall of the coupling sleeve  2   
           23  Openings in the wall  22   
           24  Connection region of the coupling sleeve  2   
           25  Stop collar of the coupling sleeve  2   
           3  Locking element 
           31  Locking arms 
           311  Ends of the locking arms 
           312  Actuating/signaling surface 
           3121  Transition surfaces 
           313 ,  314  Blocking lugs 
           3131  End surfaces of the blocking lugs  313   
           3132  Bevels of the blocking lugs  313   
           3141  Inner ends of the blocking lugs  314   
           3142  Guide webs on the blocking lugs  314   
           3143  Axial end surfaces of the blocking lugs  314   
           3144  Locking webs on the blocking lugs  314   
           32  Longitudinal stops in the coupling sleeve  2   
           4  Coupling connector 
           41  Blocking collar of the coupling connector  4   
           5  Blocking ring 
           51  Base part of the blocking ring  5   
           52  Spring part of the blocking ring  5   
           53  Blocking part of the blocking ring  5   
           6  O-ring seal