Abstract:
A rapid coupling system for establishing a connection of at least two pressurized lines in a pressure sealed manner is provided. A first coupling plug element has an operating mechanism, including a journal, in a connecting block thereof. A second coupling socket element is adapted to be connected to the first coupling element in a pressure sealed manner. A control unit is arranged in a socket element connecting block and includes a displaceable plunger having at least one cam. A pressure relief unit is connectable to at least one of the pressure lines via a pressure relief connection. When the first and second coupling elements are connected to one another, the journal of the operating mechanism displaces the control plunger, causing at least one cam of the control plunger to engage the pressure relief unit.

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to a rapid coupling system. 
   Rapid coupling systems of the generic type are known. They serve for the connection of pressurised, medium-conducting lines and are used in the context of liquids, e.g. hydraulic oils, gasses and other appropriate media. Such rapid coupling systems comprise usually two coupling elements, wherein a first coupling element is a plug element and a second coupling element is a socket element. For coupling the plug element can be plugged into the socket element. The generic rapid coupling system serves also to connect lines which are under high media pressure. To this end the connection must be established either under pressure in the socket element and another time under pressure in the plug element of the coupling system. The connection can also be established under pressure in both coupling elements or in pressureless state of both coupling elements. 
   In rapid coupling systems designed for high media pressure, e.g. of 20 to 50 MPa in one of the two or in both coupling elements, pressure release valves are known for easier handling when establishing the coupling. With the help of such pressure relief valves it is possible to reduce the pressure in the coupling element by diverting a small amount of the medium to the face of the coupling element. This facilitates the connection of the two coupling elements of the rapid coupling system. The arrangement of pressure relief valves in both coupling elements is also known. 
   From DE 41 01 001 a coupling apparatus is known wherein a pressure relief valve is arranged in the interior of at least one coupling element which is actuated when connecting the plug element with the socket element. The pressure relief valve comprises a diverting channel for the media pressure and a cut-off element that is arranged in the pressure relief valve and can be actuated by an actuator. Upon actuation of the pressure relief valve the chambers of the coupling elements associated with it form communicating vessels which leads to a pressure compensation and allows to establish the coupling with less expenditure of energy. 
   A problem that occurs frequently with rapid coupling systems is that the pressure relief valves included in the coupling elements have a complicated structure. In addition to this contamination of the media result in dogged pressure relief valves and stiff rapid coupling systems. Another disadvantage is that depending on the type of rapid coupling system the plug element or the socket element or both coupling elements must be provided with the complicated pressure relief valves. 
   So the object of the present invention is to provide a rapid coupling system of the generic type which allows a simple way of easy coupling under avoidance of the above mentioned disadvantages in all pressure ranges. 
   SUMMARY OF THE INVENTION 
   Easy coupling in all pressure ranges is enabled in that a first coupling element which can be connected with a second coupling element in order to establish a pressure sealed connection between at least two pressurised lines and that an external pressure relief unit is allocated to the rapid coupling system which is connected with at least one of the pressurised lines via at least one pressure relief connection. 
   The first coupling element to establish the rapid coupling is a plug element and the second coupling element is a socket element. The plug element and a journal are located together in a connecting block pertaining to the plug element. The socket element is arranged together with a control unit in another connecting block pertaining to the plug element. This ensures a very compact and functional establishment of the rapid coupling. 
   A preferred embodiment of the invention provides that the external control unit engages in the external pressure relief unit. The pressure relief unit is located in a third connecting block. The control unit comprises a displaceable control plunger with at least one cam. The control plunger with the cam engages in a pressure relief valve system which is arranged in the interior of the pressure relief unit. Depending on the position of the plug element in relation to the socket element, the pressure relief valve system can be opened and closed by means of the said cam. This provides a pressure relief unit that is characterised by a high operational reliability. 
   Preferred according to the invention is further a pressure relief connection between at least one pressurised line and the pressure relief unit wherein each line resp. each coupling pair—plug element and socket element—of the rapid coupling system is allocated a pressure relief connection and a pressure relief valve system. The pressure relief valve system is allocate a pressure chamber and the pressure relief line. When the in-line arranged pressure relief valve system is opened the pressure relief connection towards the pressure chamber and the pressure relief line is released. 
   A preferably preferred embodiment of the invention further provides for several coupling pairs to be integrated in the rapid coupling system. In this case several lines are connected each with one pressure relief valve system and each through a pressure relief connection. The opening of the pressure relief valve systems depends on the control unit through which the medium streams into the pressure chamber—and from there into the joint pressure relief line. Depending on the prevailing pressure in the pressure relief line and the coupling pair, a pressure relief of the coupling pairs of the rapid coupling system occurs. 
   In a preferred embodiment of the invention it is possible to synchronise the opening of the pressure relief valve system during coupling by means of the control unit in accordance with the cam located on the control plunger. This way the pressure compensation of several coupling pairs is carried out synchronously through the appropriate pressure relief connections and the joint pressure relief line. 
   In a further preferred embodiment of the invention, in order to achieve a possibly short but synchronised opening of the respective pressure relief valve system, the control plunger is arranged such that the cam moves into the pressure relief valve system, or comes out of it, exactly in the moment when the respective sealing units in the coupling elements open or close. 
   In an advantageous embodiment an internal pressure relief valve in the interior of at least one coupling element can be abandoned due to the arrangement of an external pressure relief unit. 
   In the following further preferred embodiment of the invention are described by means of one coupling pair. 
   They apply accordingly, however, for embodiments of several coupling pairs contained in the rapid coupling system. 
   Another preferred embodiment of the invention is that in a first step the pressurised line is coupled with each other which causes a simultaneous axial shifting of the journal on the plug element in the direction of the socket element. The journal shifts the control plunger while forming a stop. In the rapid coupling system a sealing unit in the socket element and a sealing unit in the plug element are released and the medium flows first from a channel in the socket element into a first chamber in the plug element. Simultaneously the cam of the control plunger actuates a pressure relief valve by means of a valve ball thus opening a pressure relief valve system and consequently the pressure relief unit. 
   Further preferred in a second step following the first one, another sealing unit of the plug element is opened which triggers the coupling pair of the rapid coupling system to open completely. The pressure relief valve system is still open due to the continuous engagement of the cam on the valve ball of the control plunger that is pushed further into the pressure relief valve system, so that a pressure relief continues. 
   In a third coupling step the journal shifts the control plunger axially and connects the chamber and the channel with each other while simultaneously releasing the valve. The cam of the control plunger keeps the pressure relief valve system open and releases the pressure relief connection to the pressure relief chamber and the adjacent pressure relief line in order to allow a pressure relief within the rapid coupling system. 
   In the last step the sealing unit opens completely thus causing the cam of the control plunger to withdraw from the pressure relief valve system due to further axial shifting of the coupling elements and the journal while releasing the valve ball and the pressure relief valve, and the pressure relief valve system to close allowing a pressure build-up in the rapid coupling system. 
   In a preferred embodiment of the invention there can furthermore a control plunger with several cams be provided, so that opening and closing of the rapid coupling system is possible by means of repeated opening and closing of one or several pressure relief valve systems. In this case a pressure relief is possible at different times in the coupling elements of the rapid coupling system. 
   Further preferred embodiment of the invention result from the other features specified in the sub-claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be further explained in the following by means of the related drawings. In these: 
       FIG. 1  is an external view of a rapid coupling system in an uncoupled state; 
       FIG. 2  is a cross-sectional view of the rapid coupling system in an uncoupled state; 
       FIG. 3  is a cross-sectional view of the rapid coupling system in a partially coupled state in a first coupling step; 
       FIG. 4  is a cross-sectional view of the rapid coupling system in a partially coupled state in a second coupling step; 
       FIG. 5  is a cross-sectional view of the rapid coupling system in a coupled state, and 
       FIG. 6  is an external view of a rapid coupling system in a coupled state. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The rapid coupling system as a whole denoted by  100 —depicted in  FIG. 1  in an uncoupled state—provides a principally known basic construction. It consists of two coupling elements  12  and  14 . Wherein the coupling element  12  is a plug element and the coupling element  14  is a socket element. The particularity of the rapid coupling system  100  is that several plug elements  12  of several pressurised lines L 1 , L 2 , L 3 , L 4  to be connected with each other are arranged in a connecting block  18 . The opposing socket elements  14  of the plug elements  12  are combined in one connecting block  16 . The lines L 1 , L 2 , L 3 , L 4  extending from the socket elements  14  are not depicted in FIG.  1 . 
     FIG. 1  shows further a journal  42  that is centrically arranged in the connecting block  18  between the lines Lx. Opposing the said journal  42  there is a control plunger  44  between the socket elements  14  that is centrically arranged in the connecting block  16 . 
   The socket elements  14  are furthermore connected with a pressure relief unit  70 . The elements of the pressure relief unit  70  are connected with the connecting block  16  through another connecting block  82 . 
   Integrated in the pressure relief unit  70  are the pressure relief valve systems  50 . In  FIG. 1  only the external connections of the pressure relief valve systems  50  are visible. Each line Lx is allocated a separate pressure relief valve system  50 . The existing pressure relief valve systems  50  are connected with a joint pressure relief line  48  by a pressure relief chamber  46  that is not visible in Fig. 
     FIG. 2  shows a cross-section through a rapid coupling system  100  in the uncoupled state. To facilitate the figure, only one plug element  12  and one socket element  14  of the rapid coupling system  100  for one line Lx are depicted in cross-sectional view. The plug element  12  is connected with a journal  42  through the connecting block  18 . 
   In starting position, the housing face  24  of the housing  22  of plug element  12  is in contact with an axially displaceable housing element  62  of the socket element  14 . On the other hand, the face of a tappet  28  which seals by means of a sealing unit  38  on the housing  22  of the plug element  12 , is in contact with a fixed mounted sliding element  26 . 
   The sliding element  26  runs in a sliding element bearing  40 . The tappet  28  which is axially guided in a tappet bearing  86  is pressed against the sealing unit  38  by the force of a spring element  76  and shuts of a chamber  34  from the atmosphere. The chamber  34  is shut off against a medium-conducting, pressurised channel  68  by a valve  30  on a sealing element  32 . 
   A pressure relief valve  56  can be arranged in the valve  30 . The function of the rapid coupling system  100  according to the invention in accordance with the explanations of the other figures, however, is provided also without such pressure relief valve. 
   The socket element  14  seals an external housing  20  against the connecting block  16 . It is mounted non-displaceable in relation of connecting block  16 . Next to the exterior housing  20  on the interior surface there is a housing element  21  which forms a stop on a housing block  84  and seals by means of a sealing unit  36  against the housing block  84  of the socket element  14 . 
   The sealing unit  36  of housing element  21  further seals an adjacent housing element  62  located more in the interior against the exterior housing  20 . 
   The housing element  62  is arranged on the interior surface of the housing element  21 . Another axially displaceable housing element  64  is arranged at a certain distance to a housing element  23  in the interior of the socket element  14 . The housing element  62  is axially displaceable between the housing elements  62  and  64  as well as  21  and  23  working against the force of spring elements  58  and  60 . Spring element  58  is arranged between the housing elements  62  and  23  and spring element  60  is arranged between the housing elements  64  and  23 . In the uncoupled state, the sliding element  26  seals the socket element  14  against die axially displaceable housing element  64  by means of a sealing unit  88 . 
   Next to the sliding element  26  there is a channel  66  that is open towards the medium-conducting line Lx of the coupling element  14 . The channel  66  is integrated in the housing block  84 . 
   On the housing block  84 , there is the control plunger  44  integrated in the connecting block  16  by means of a bearing housing  78  and kept at a fixed parallel distance to the rapid coupling system  100 . 
   The control plunger  44  is aligned along the same axis with the journal  42  and forms a stop  80  in the bearing housing  78  in the uncoupled state. The end of the control plunger  44  which does not face the journal is connected by means of a sealing unit with an intermediate bearing  90  and by means of another sealing unit with the pressure relief unit  70 . In the uncoupled state, the control plunger  44  does not engage in the pressure relief unit  50  by means of a control unit  10 . 
   The control unit  10  comprises the control plunger  44  and at least one cam  54  that is arranged on the control plunger  44 , which in the uncoupled state does not engage in the pressure relief unit  50 . 
   The pressure relief unit  50  comprises a valve spring  72  and a valve ball  74 . The valve ball  74  is arranged radially on the control plunger  44 . 
   Extending from the pressure relief chamber  46  there is, on the one hand, at least one pressure relief connection  52  to at least one medium-conducting pressurised line Lx. Such pressure relief connection  52  is closed by the pressure relief valve system  50  in the uncoupled state. On the other hand, the pressure relief chamber  46  is allocated a pressure relief line  48  which is jointly available via the pressure relief valve system  50  to all existing pressure-releasing pressure relief lines  52 . All elements of the pressure relief unit  70  are also accommodated in the connecting block  82 . 
   On the basis of the arrangement of the rapid coupling system  100  as specified in FIG.  1  and  FIG. 2 , a gradual pressure relief of the rapid coupling system  100  can be achieved in the plug element  12  and the socket element  14 . In the following it shall be assumed that, in the uncoupled state, both coupling elements  12  and  14  in the channels  66  and  68  are pressurised. 
     FIG. 3  shows a cross-section through a rapid coupling system  100  in a first coupling step. In this first coupling step the socket element  14  is pressure-releasable during coupling. The function of the pressure relief is specified in detail in the following. To this end only those reference numbers are referred to which are required to explain the action. The other reference numbers correspond to those specified in  FIGS. 1 and 2 . 
   The starting position is the uncoupled rapid coupling system  100  as displayed in FIG.  2 . By axial displacement of the connecting block  18  with the integrated plug element  12  and the journal  42  in the direction of the socket element  14 , the housing end wall  24  of the housing  22  is pushed into the socket element  14 . 
   As a result, the housing elements  62  and  64  are axially displaced in the direction of the channel  66  against the spring elements  58  and  60 . 
   As a result of the opposed force emanating from the stationary sliding element  26 , the tappet  28  is displaced axially in the direction of the channel  68  working against the force of the spring element  76 . 
   As a result of this arrangement the sealing unit  88  of the sliding element  26  on housing element  62  is released. At the beginning of the axial displacement the journal  42  gets in contact with the control plunger  44 . 
   The control plunger  44  is pushed deeper into the pressure relief unit  70  than in starting position. The cam  54  engages with the valve ball  74 . Against the action of the valve spring  72  the valve ball  74  releases an opening between the pressure relief unit  52  and the pressure relief chamber  46 . Due to the pressure relief chamber  46  being connected with a unpressurised pressure relief line  48 , a pressure relief occurs in the socket element  14  and partially in the plug element  12  according to the principle of communicating vessels. 
   The pressure relief action carries on through the pressure relief connection  52  via the channel  66  up to the chamber  34  in the plug element  12 . Due to this displacement the control plunger  44  leaves its stop  80  in the bearing housing  78 . 
     FIG. 4  shows a cross-section through the rapid coupling system  100  in the coupled state after the first coupling step. 
   It is recognisable that due to the axial displacement of the housing elements  62  and  64  the sealing unit  88  is released and providing a connection to the chamber  34 . The spring element  76  of the plug element  12  is already in a state of partial tension. The pressure relief valve system  50  is open and a pressure compensation occurred through channel  66  and the pressure relief connection  52 . 
   In continuation of the movement of the connecting blocks  16  and  18  towards each other the control plunger  44  continues to travel deeper into the pressure relief valve system  50 .  FIG. 4  shows that the cam  54  is further arranged within the range of the valve ball  74 . 
   A special embodiment which is not essential for the invention, however, enables a first pressure relief by means of a pressure relief valve  56  in one of the two coupling elements  12  or  14 . In this embodiment the pressure relief valve  56  is arranged in the plug element  12 . 
   The end of tappet  28  facing the valve  30  engages on a push pin integrated in valve  30 , which releases a relay flow in the existing gaps of valve  30 . An arrangement like this is known already and serves in this place only to explain and complete the function of the rapid coupling system  100 . 
   During the triggered relay stream leading to a first pressure compensation between the chamber  34  and the channel  68  the valve  30  keeps still resting against the sealing element  32 . 
   During the further coupling process the valve  30  is further displaced axially in the direction of the channel  68  caused by the action of tappet  28 . The sealing element  32  is released and the channel  68  is released from pressure by means of the pressure relief unit  70  via chamber  34 . 
     FIG. 4  shows further that the journal continues to displace the control plunger  44  deeper into the pressure relief unit  70  simultaneously. Once the end of the cam  54  is reached the cam starts travelling away from the valve ball  74 . Once the cam  54  starts travelling away from the valve ball  74  the pressure relief valve system  50  closes and consequently the pressure relief chamber  46  is closed. 
   Such pressure relief function according to the  FIGS. 3 and 4  can be achieved for any number of coupling pairs  12  and  14  in that several pressure relief valve systems  50  and the related pressure relief connections  52  are arranged radially around the pressure relief chamber  46 . Other non-radial arrangements are also conceivable. 
   Due to the cam  54  being arranged all over the circumference of the control plunger  44 , the control unit  10  acts equally pressure-releasing on several coupling pairs  12  and  14  via the pressure relief valve system  50  and the pressure relief connections. 
     FIG. 5  shows the rapid coupling system  100  in a completely open coupled state. 
   The spring element  76  is displayed in a state of complete tension. The tappet  28  presses against the valve  30  and the housing  22  of the plug element  12  is displaced completely in the direction of the socket element  14 . The housing face  24  has pressed the housing element  62  against the spring elements  58  and  60  so that the sealing unit  88  of the sliding element  26  releases completely the connection between the chamber  34  and the channel  66 . 
   The control plunger  44  is pushed deeper into the pressure relief unit  70  by the journal  42  so that the cam  54  travels away from the valve ball  74  and the effect on the valve body is stopped. The valve ball closes under the effect of the spring  72 . As a result, the pressure relief function of the pressure relief unit  70  is discontinued. Inside the rapid coupling system  100  the full media pressure builds up in the associated open coupling elements  12  and  14 . 
   In the last phase of the coupling process of the connecting blocks  18  and  16  the plug element  12  is displaced together with the socket element  14  relative to the exterior non-displaceable housing  20  of the socket element  14  inside the connecting block  16 . The plug element  12  as a whole and the socket element  14  guided by the housing element  21  are displaced together with the housing block  84  in the exterior housing  20 . Because of the connection between the housing block  84  and the bearing housing  78  by means of the intermediate bearing  90  the connecting block  82  as a whole is displaced by the same distance together with the integrated pressure relief unit  70 . The rapid coupling system  100  has now reached its coupled end position. 
     FIG. 6  shows an external view of the rapid coupling system  100  in a coupled state. Visible are the coupled lines L 1  and L 2  between the connecting blocks  16  and  18  and the connecting block  82  which accommodates the pressure relief unit  70 . The lines L 3  and L 4  are located invisibly behind the lines L 1  and L 2 . 
   The pressure relief unit  70  is conducted by means of the pressure relief chamber  46  which is invisible from outside towards the common pressure relief line  48 . Just implied by their locking elements are the pressure relief valve systems  50  which are arranged radially to the control plunger  44  and which are opened and closed during the coupling process by means of the journal  42  and the control plunger  44 . Further the exterior housing  20  of the plug element  12  is visible. The housing block  84  between the connecting blocks  16  and  82  makes  FIG. 6  complete. 
   The rapid coupling system  100  is opened the other way round. 
   In accordance with the coupling steps specified in  FIGS. 4 and 3 , first the chamber  34  opposite of channel  68  is closed by means of the valve  30  under pressure relief caused by pressure relief unit  70 . 
   The force of the spring element  76  causes the tappet  28  to return to its starting position. The housing elements  62  and  64  are also displaced back to their starting positions caused by the force of the spring elements  58  and  60  so that the sealing unit  88  of the sliding element  26  rests sealing again on the housing element  64 . 
   This seals the channel  66  in the socket element  14  under pressure relief against the chamber  34  or tappet  28  respectively. 
   Simultaneously the pressure relief unit  70  closes in that the control unit  10  leaves the area of the valve ball  74  in the pressure relief unit  70 , and pressure relief is discontinued. So subsequent to the separation of the connecting blocks  16  and  18 , each of the coupling elements  12  and  14  for itself is sealed against the pressure relief unit  52  as well as on its face wall. 
   LIST OF REFERENCE NUMERALS 
   
       
         100  rapid coupling system 
         10  control unit 
         12  plug element 
         14  socket element 
         16  connecting block 
         18  connecting block 
         20  exterior housing 
         21  housing element 
         22  housing 
         23  housing element 
         24  housing face 
         26  sliding element 
         28  tappet 
         30  valve 
         32  sealing element 
         34  chamber 
         36  sealing unit 
         38  sealing unit 
         40  sliding element bearing 
         42  operating mechanism (journal) 
         44  control plunger 
         46  pressure relief chamber 
         48  pressure relief line 
         50  pressure relief valve system 
         52  pressure relief connection 
         54  cam 
         56  pressure relief valve 
         58  spring element 
         60  spring element 
         62  housing element 
         64  housing element 
         66  channel 
         68  channel 
         70  pressure relief unit 
         72  valve spring 
         74  valve ball 
         76  spring element 
         78  bearing housing 
         80  stop 
         82  connecting block 
         84  housing block 
         86  tappet bearing 
         88  sealing unit 
         90  intermediate bearing 
         91  sealing unit 
       Lx lines