Abstract:
A coupling for connection to a source of fluid pressure such as in a breathing-protection. The coupling has a socket end and a plug end insertable into the socket end. The socket end has a body and a locking sleeve on the body. As the plug end is inserted into the socket end, the locking sleeve is moved axial from a first axial position to a second axial position locking the plug end within the socket end, and rotationally from a release position to a locked position delimiting the movement of the locking sleeve from the second axial position to the first axial position. When the coupling is pressurized, a piston within the body is moved from a retracted position to an extended position delimiting the rotational movement of the locking sleeve from the locked position to the release position.

Description:
CROSS-REFERENCE TO RELATED CASES 
     The present application claims the benefit of the filing date of German Patent Application No. 10 2008 016 029.6, filed Mar. 28, 2008, the disclosure of which is expressly incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The invention concerns a plug coupling for directing a fluid under pressure, especially for breathing-protection devices, with a box-shaped receiving part and a plug part within it, into which a plug can be inserted, whereby the receiving part has a valve housing with locking means mounted inside it to lock the plug part into the plugged-in position in the receiving part and a locking sleeve cooperating with the locking means, arranged to be movable back and forth between two axial positions and also rotatable in such a way that the locking sleeve, which is spring-prestressed in the axial direction, fixes the locking and in the other axial position releases a movement of the locking means as a release position for the plug part in the locked position in the sense of removing the plug part from the receiving part, and that the locking sleeve, also spring-prestressed in the direction of rotation and can be rotated between a first rotational position and a second rotational position on the valve housing, is locked with the valve housing in its first rotational position and in its second rotational position, it permits an axial movement of the locking sleeve in the released position, and whereby an additional security device is provided, applied with the plug part plugged into the plug coupling, against a rotation of the locking sleeve with increasing pressure of the fluid led through it. 
     A plug coupling with the above-mentioned characteristics is known from DE 102005025548 A1, now EP 1 729 051 B1. The plug coupling described therein consists, in its parts most essential for understanding the described invention, of a base body as the receiving part and a plug part. On the base body, a locking sleeve is arranged so as to move between two axial positions, which in the first axial position establishes locking means for locking the plug part in the receiving part and in the second axial position releases the locking device in terms of removing the plug part from the receiving part. In order to make an unintentional detachment of the plug part more difficult, the locking sleeve is also arranged in such a way that it can rotate between two rotational positions so that movement of the locking sleeve from the one axial position, in which the locking means are locked, is blocked until the locking sleeve is changed from a first rotational position to a second rotational position. A fluid chamber between the base body accepting the receiving part and the locking sleeve acts as a further security measure against a detachment of the plug coupling with the plug coupling under pressure. This fluid chamber communicates with the fluid led through the plug coupling and serves to generate a force corresponding to the prevailing pressure hold to hold the locking sleeve in the locking position. The force generated is greater than the force that a user can apply by hand if he tries to move the locking sleeve into the unlocked position. 
     The known plug coupling is associated, first of all, with the disadvantage that the arrangement of the fluid chamber in the receiving part and its connection to the locking sleeve causes a complicated structure of the plug coupling with corresponding individual parts, which is according expensive in production and assembly. Furthermore, it is a disadvantage that securing the locking sleeve is aimed at making it more difficult to move the locking sleeve when the plug coupling is under pressure and it is therefore based on a force closing, so that, for example, at a lower pressure in the plug coupling, no adequate security against detachment of the plug coupling can be given. 
     The invention is therefore based on the task of improving the security of the plug coupling with the characteristics mentioned in the introduction against unlocking when the plug coupling is under pressure and at the same time simplifying the plug coupling in its structure. 
     BROAD STATEMENT OF THE INVENTION 
     In its basic idea, the invention envisions that the security device consists of at least one piston arranged in a hole running radially in and connected to the pressure-directing channel of the plug coupling, which, when the plug coupling is closed by the applied pressure, the piston moved into a position that projects beyond the outer perimeter of the valve housing and prevents a rotary movement of the locking sleeve. 
     The invention is connected with the advantage that by means of the piston arranged with pressure applied in the valve housing, the locking sleeve is already positively locked in its first rotational position, which forms the locking position for the plug part, so that when the plug coupling is under pressure the locking sleeve can already not be moved to its second rotational position, in which, a movement of the locking sleeve into its release position for the locking means is at all possible in general. This implies that the pressure control for the piston is essentially simpler to handle that the control in the state of the art for the force to be generated for the force closing. With this simpler control, the structure of the plug coupling becomes simpler, with fewer individual parts. 
     According to one embodiment example, an additional security measure is envisioned, with which detachment of the plug coupling is prevented when the locking sleeve has not completely entered the locking groove in the receiving part. In this case, intermediate positions of the locking means are conceivable, in which the locking sleeve still lies with one part over the piston so that when the piston is under pressure, it cannot be moved out. If the locking sleeve is then rotated back from such an intermediate position to its position permitting movement, unlocking of the plug coupling under pressure is then possible. In order to exclude such a possibility, the invention foresees that the locking sleeve is provided, on its surface facing the piston, with an indentation for positive-locking entrance of the piston into the locking sleeve and for fixing the locking sleeve in both its axial and rotary positions. Thus, if the locking sleeve is rotated in the direction of the rotational position permitting the release position, then the piston under pressure automatically locks the locking sleeve in the indentation and thus prevents it from possibly being moved in spite of the locking sleeve being in the moving position. 
     According to a first embodiment of the invention, it is envisioned that the locking sleeve has a cam springing radially inward that can be moved in the second rotational position, which makes axial movement possible, along a flattening formed on the valve housing, and in the first rotational position, locked with the valve housing, enters the adjacent locking groove of the valve housing on, whereby the hole formed in the valve housing is equipped in such a way that the piston stands out in its pushed-out position above the flattening of the locking housing and thus prevents the locking sleeve from being rotated from the first rotational position to the second rotational position. In this embodiment, the piston projecting out from the flattening of the valve housing formed for the security sleeve is prevents the locking sleeve from rotating into its rotational position in which, after the cam comes free from the locking groove of the valve housing, the cam is equipped with the flattening of the valve housing, and it be moved along the flattening. 
     In this case, it can be envisioned that the piston is pre-stressed by means of a pressure spring arranged in the hole in its position inside the valve housing. by interpreting the force of the pressure spring, the response pressure at which pressure of the fluid being led through remaining in the plug coupling can thus be set, overcoming the spring force of the pressure spring and moving the piston into the hole in its pushed-out position, where the piston fixes the locking sleeve. If the plug coupling is set to detach without pressure the pressure spring thus moves the piston back into its position lying within the valve housing, in which the locking sleeve can be rotated. 
     To seal the hole, it is envisioned, according to one embodiment example, that at the radially outward end of the hole, a tight sleeve is placed to seal the hole and for sealed guiding of the piston, against which the pressure spring with one end lying on the piston is supported. 
     To implement the additional security in this embodiment of the invention, it can be envisioned that an indentation to receive the piston in its pushed-out position is formed in the bottom of the cam facing the valve housing. 
     According to an alternative embodiment of the invention, it is envisioned that the locking sleeve have a cam springing radially inward that, in the second rotational position of the locking sleeve, which makes axial movement possible, can be moved along a flattening formed on the valve housing and in the first position rotational position, locked with the valve housing, enters a locking groove adjacent to the valve housing in the circumferential direction, whereby the hole formed in the valve housing is arranged outside the flattening and in the circumferential segment holding the piston in its second rotational position, permitting the piston to be held in its pushed-in position inside the locking sleeve and an adjacent indentation to received the piston in its pushed-out position are arranged. In this embodiment, arranging a spring applied to the piston can be omitted, since the movement of the piston is controlled, on the one hand, by the effective pressure and, on the other hand, by the formations on the inside of the locking sleeved. To this extent, in this embodiment example, very low pressures are already sufficient to move the piston into its pushed-out position. On the other hand, the piston is pushed back to its pushed-in position in the hole by the rotation of the locking sleeve. 
     In view of a control of the piston movement related to this, according to one embodiment example of the invention, it is envisioned that the transition between the circumferential segment holding the piston in the pushed-in position and indentation is formed as a striking edge for the piston acting in the direction of rotation, with a radius pressing the piston into the hole. 
     In this embodiment example of the invention, too, it is envisioned that in the circumferential segment holding the piston in its pushed-in position, and indentation is made to received the piston in its pushed-out position, so that with this measure, it is again ensured that when the locking sleeve is not set back sufficiently, and the rotation sleeve into the pushing position, the piston under pressure is in the assigned indentation and the locking sleeve is thereby positively locked, although the locking sleeve, after the cam is provided and the valve housing is flattened, is in a rotational position in which movement of the locking sleeve is possible, in principle. 
     In order to be able to unlock this locking after such a locking has occurred, it can be envisioned that the edged delimiting the indentation in the circumferential direction are formed with a radius that presses the piston into the hole. In this example embodiment of the invention, it can be envisioned that the piston is sealed against the hole by means of seal arranged on its circumference. 
     It can be envisioned that cams and assigned flattenings in a symmetric arrangement on sides of the valve housing and the locking sleeve lying opposite each other, and correspondingly two holes with pistons and assigned circumferential segments and indentations are arranged. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein: 
         FIG. 1  shows a plug coupling in a schematic section side view in an uncoupled state, with the plug part not coupled and a locking sleeved in the release position; 
         FIG. 2  shows the object of  FIG. 1  in a partial cross-section view of the locking sleeve and a security device for it; 
         FIG. 2A  shows the object of  FIG. 1  in a partial cross-section as in  FIG. 2 , but with the security device in an extended position; 
         FIG. 3  shows the object of  FIG. 1  with the plug part coupled in; 
         FIG. 4  shows a cross-section view corresponding to  FIG. 3  in a representation according to  FIG. 2 ; 
         FIG. 5  shows another embodiment example of the plug coupling, in a schematic section side view in an uncoupled state and with the locking sleeve in the release position; 
         FIG. 6  shows the object  FIG. 5 , in a partial cross-section view of a locking sleeve and a securing device for it; 
         FIG. 7  shows the object of  FIG. 5  in with the plug part uncoupled; and 
         FIG. 8  shows cross-section view of the uncoupled state according to  FIG. 7 , in a representation corresponding to  FIG. 6 . 
     
    
    
     The drawings will be described further in connection with the following Detailed Description of the Invention. 
     DETAILED DESCRIPTION OF THE INVENTION 
     As results from  FIG. 1 , first of all, the plug coupling consists of a receiving part  10  and a plug part  11  that can be plugged into it. To the extent that the structure of the plug part  11  is not involved for understanding of the present invention, it is only emphasized that a locking groove  12  is formed in the receiving part  10  for the locking of the plug part  11  in the receiving part  10 , to be described later. 
     The receiving part  10  consists of a valve housing  13  with a base body  14  and a base-body sleeve  15  screwed to it, in the front region of which indentations  16  are formed, into which locking balls  17  are inserted. The base body  14  and the base-body sleeve  15  form together a receiving space  50  for the plug part  11 , in which receiving space  50  an inner control sleeve  18  is arranged. The control sleeve in this case holds the locking balls  17  away from the plug path for the plug part  11 . 
     On the outside of the base-body sleeve  15 , a locking sleeve  20  is arranged to move between a first axial position according to  FIG. 1  and a second axial position according to  FIG. 3 , specifically against the force of a pressure spring  21 . In the first axial position, which can be seen in  FIG. 1 , with the plug coupling uncoupled, the locking sleeve  20  has one arm over the assigned indentation  16  in the base-body sleeve  15  and strikes the locking balls  17  on the inner control sleeve  18  with a force acting in the radial direction of the locking-ball system  17 . If, as results from a comparison of  FIGS. 1 and 3 , the plug part  11  is pushed in, striking the inner control sleeve  18  in the receiving space  50  of the valve housing  13 , then the rocking balls  17  lock into the locking groove  12  of the plug part, after which the locking sleeve  20  is pushed by the action of the pressure spring  21  into its second axial position ( FIG. 3 ), in which the locking sleeve  20  fixes and secures the locking balls  17  in the locking groove  12  of the plug part  11 . 
     The locking sleeve  20 , in the embodiment example presented, consists of several parts, which, however, are determined constructively and functionally and are not of importance for implementing the invention. 
     As results from viewing  FIGS. 1 to 4  together, a flattening  27  is formed, which extends in the longitudinal direction of the valve housing  13  on the base body  14  of the valve housing  13 , the length of which corresponds to at least the path of movement of the locking sleeve  20  between its release position ( FIG. 1 ) and its secure position ( FIG. 3 ). The locking sleeve  20  has a cam  29 , which springs inward, which, in one rotational position of the locking sleeve  20  with the flatting  27 , is oriented in such a way that the cam  29  slides over the flattening  27  and thereby makes a movement of the locking sleeve  20  possible. Furthermore, a locking groove  28  is formed in the base body  14  to receive the cam  29 , into which the cam  29  locks in the coupled position of the plug coupling, as results from viewing  FIGS. 3 and 4  together. The locking sleeve is thereby subject to the action of a pressure spring, which prestresses the locking sleeve  20  in the position in which the cam  29  lies in the locking groove  28 . Thus, starting from the representation according to  FIGS. 1 and 2 , if the plug part  11  is coupled into the receiving part  10 , then the locking sleeve  30  is moved due to the action of the spring  21  into the secure position according to  FIG. 3 , and in this position, it rotates into its second rotational position, in which the cam  29  comes free from the locking groove  28  and is oriented toward the flattening  27 , so that a movement of the locking sleeve  20  along the flatting  27  is possible. 
     To secure the plug coupling against detachment of the plug coupling under pressure, a hole  23  running radially in the base body  14  is formed, which is arranged in such a way that, on the one hand, it is connected to the passage channel  22  of the coupled plug coupling, which is under pressure, and at its other end, it ends in the flattening  27 . In the hole  28 , a piston is arranged so as to movable, whereby a sealing sleeve  25  is placed at the end of the hole  23  that opens in the flattening  27  and seals the hole  23  that is under pressure when the plug coupling is coupled. the piston  24  is fed in the sealing sleeve  25  in a sealed manner, whereby the piston is supported, on the one sided, by a pressure spring  26 , and on the other side on the sealing sleeve, prestressed in its pushed-in position ( FIG. 2 ). 
     If the hole  23  comes under pressure with the plug coupling coupled and the fluid under pressure been fed through, then the piston  24  is pushed out against the spring  26  acting on it, so that one end projects from the flattening  27 . Since in this coupled position, the locking sleeve  20  is in a rotational position in which its cam  29  lies in the locking groove  28 , rotation of the locking sleeve is prevented with piston pushed  25  out under pressure. In this way, it is ensured, through the positive-locking security device, that uncoupling of the plug coupling is not possible. 
     As an additional measure, the cam  29  has on its bottom, facing the base body  14 , an indentation  30  to receive the piston  24  in its pushed out position. Specifically, to the extent that in the front locking position for the locking balls  17 , the locking sleeve is not completely in its secure position with the cam  29  rotated in the locking groove  28 , but has assumed an intermediate position, this intermediate position can be viewed in such a way that the end of the cam  29  is still over the piston, so that the piston  26  under pressure cannot come completely out from the hole  23 , but only at the bottom against the cam  29 . From such an intermediate position, no fixation of the locking sleeve  20  is given by the piston under pressure. As depicted in  FIG. 2A , it is now ensured, by the indentation  29  envisioned on the cam  29 , that when the security sleeve  20  is rotated into its release position, the piston  24  under pressure is locked into the indentation  30  of the cam  29  and thus the locking sleeve  20  is positively locked on the base body of the valve housing  13 , so that movement of the locking sleeve  20  is excluded. 
     If, with the plug coupling is placed without pressure, it is uncoupled, then the spring  26  presses the piston  24  back into its initial position, in which rotation of the locking sleeve  20  into its rotational position that makes movement possible. 
     The embodiment example represented in  FIGS. 5 through 8  differs from the embodiment example described above in  FIGS. 1 through 4  essentially in an alternative formation of the pressure-controlled piston arrangement for fixing the locking sleeve  20 . To the extent that additional constructive differences exist in the formation of the valve housing  13  and the plug part  11 , these differences are not further relevant for the present invention, so they will not be discussed separately. It will only be noted that a hand wheel  35  is envisioned for activation of the locking sleeve and connected appropriately to the locking sleeve and that a unified pressure spring  36  is envisioned to be applied by the locking sleeve  20  or the hand wheel  36  with action in both axially and in rotationally. 
     To the extent that also in this embodiment example a movable piston  24  is again envisioned as a security device for the locking sleeve  20 , under pressure in a hole  23 , a spring applied to the piston is omitted in this embodiment example. Rather, control of the piston between its position pushed out from the hole  23  and its pushed-in position in the base body  14  by rotation of the locking sleeve  20 , which encloses the valve housing completely for this purpose. On the inside of the locking sleeve  20 , a circumferential segment  40  is first formed, which holds the piston  24  in the pushed-in position in hole  23 . In this position, according to  FIGS. 5 and 6 , the locking sleeve  20 , with the cam  29  formed on it is directed to the flattening  27  of the base body  14 , and can thus move between the axial positions assigned to it. On the circumferential segment  40 , an indentation  41  is connected, which, on the one hand, provided sufficient free space for the piston  24  to be pushed out from the hole  23 , so that in the pushed-out position, the piston  24  projects over the surface of the base body  14  of the valve housing  13 . The striking edge  42  between the circumferential segment  40  and the indentation  41  thus represents a positive locking for fixation of the locking sleeve  20  in the locking position represented in  FIGS. 7 and 8 , in which, because of the effect of the rotational-pressure spring  36 , the locking sleeve  20  is rotated into its rotational position in which the cam  29  lies in the locking groove  28  and prevents movement of the locking sleeve  20 . If the piston  24  is pushed out and thus lies in the indentation  41  of the locking sleeve  20 , because of the pressure applied outward in the hole  23 , rotation of the locking sleeve  20  into its other rotational position according to  FIG. 6  is excluded. 
     In this embodiment example of the invention, the movement path of the piston  24  is controlled solely by the pressure prevailing in the passage channel  22 , whereby the piston  24  is sealed against the hole  23  by a seal  46  arranged on its outer circumference. Since, to the extent that the piston  24  can move slightly in the hole  23 , low pressures are already sufficient to contribute to the movement of the piston  24 . To the extent that a back movement of the piston  24  into the hole  23  is to occur with the plug coupling free of pressure, this takes place by a rotation of the locking sleeve  20  from the rotational position represented in  FIG. 8  to the rotational position represented in  FIG. 6 , and for this purpose, the striking edge  42  is implemented with an appropriate radius to facilitate movement of the piston  24 . 
     As in the embodiment example described in  FIGS. 1 through 4 , an indentation  43  is also envisioned in this embodiment example, in which the piston  24  under pressure is locked when the locking sleeve  20  is to be rotated into its movement position while still under the action of pressure. In order that this security position can also be released, the edges  44  delimiting the indentation  43  are formed with an appropriate radius that facilitates the piston  24  being pushed into the hole when free of pressure. 
     In the embodiment example represented in  FIGS. 5 through 8 , two holes each are envisioned in a symmetric arrangement with two pistons, and correspondingly, the locking sleeve has two cams  29  and two circumferential segments  29  and indentations  41 , and the base body  14  of the valve housing  13  is also equipped with two flattening  27  and two locking nuts  28 . 
     Otherwise, however, the plug coupling according to  FIGS. 4 through 8  fulfills the same function as that described in the embodiment example according to  FIGS. 1 through 4 . 
     As it is anticipated that certain changes may be made in the present invention without departing from the precepts herein involved, it is intended that all matter contained in the foregoing description shall be interpreted as illustrative and not in a limiting sense. All references including any priority documents cited herein are expressly incorporated by reference.