Bayonet Catch for a Line of Pressurized Medium

The present invention relates to a valve having a bayonet catch for connecting it to a discharge line.

The valve has a tubular body, a lever journalled pivotably to the body for turning a valve means, as well as coupling elements at the forward end of said body for disconnectably coupling to it the connecting plug of a line, said coupling elements comprising a push-pull sleeve surrounding the forward end of the body.

A problem with such prior art bayonet catches for pneumatic lines is that, as the catch is opened, the working side pressure discharges at great force through a plug just disconnected with the consequence that the line might get out of hand and cause damage by hitting surrounding objects.

In order to overcome this problem, an object of the invention is to provide a bayonet catch that cannot be released until the working pressure within the coupling has been allowed to discharge to atmosphere in a controlled manner while the plug is still connected to the bayonet catch. This object is achieved by the invention on the basis of the characteristics set out in the annexed claims.

One embodiment of the invention will now be illustrated and described with reference made to the accompanying drawings.

FIG. 1 shows a bayonet catch of the invention in longitudinal section with the catch connected and the valve in open position.

FIG. 2 is a plan view of the same bayonet catch.

FIG. 3 shows diagrammatically the relative positions of various bayonet catch components with the valve closed and the connecting plug disconnected.

FIG. 4 is similar to FIG. 3 illustrating the stage when the plug is pushed in and the valve is still closed.

FIG. 5 shows the stage when operating lever has been turned through 15.degree. for displacing a push-pull sleeve to close a bleed passage before the valve is opened.

FIG. 6 shows the stage when lever has been turned to completely open the valve with other components remaining in the position shown in FIG. 5.

The bayonet catch comprises a single-piece tubular body member 10 fitted with a pivotably journalled operating lever 1. Lever 1 turns a ball-shaped valve means 12 for opening and closing the flow of a pressurized medium, e.g. compressed air, from inlet side to outlet side. The inlet line is connected to the left-hand end of body 10 and the outlet line is connected to a connecting plug 11. Body 10 is provided with passages for balls 9 acting as coupling elements which, when plug 11 is inserted in position, sink in a groove 15 made in plug 11. A push-pull sleeve 4 prevents balls 9 from rising out of groove 15 with the consequence that plug 11 remains in position. The end of plug 11 rests against a seal 8 which is fitted in a sleeve 13 and biased by a spring 7. Between valve means 12 and seal 8, the body is provided with an outlet passage 14 which, in the case shown in FIG. 1, is closed by a seal 6 of said push-pull sleeve 4.

A dowel 2 mounted on operating lever 1 is engaged in a slideway 3 made in push-pull sleeve 4, the configuration of said slideway 3 determining the axial position of push-pull sleeve 4 at various swing angles of lever 1. Furthermore, a spring 5 urges push-pull sleeve 4 towards the connecting position.

Operation of the bayonet catch proceeds as follows.

In the basic position shown in FIG. 3, the inlet side is pressurized and due to the position of lever 1 said ball 12 is closed. Dowel 2 is engaged in a curve at the end of slot 3 for locking lever 1 which is in its zero position, or in the position turned 90.degree. aside. The external surface of sleeve 13 keeps balls 9 projected, said sleeve 4 thus remaining in retracted position. Shown in FIG. 4 is the connection of a connecting plug. Plug 11 is pushed into body 10, said seal 8 sealing the space between body 10 and plug 11. Sleeve 13 moves from under said balls 9 allowing them to drop in groove 15 formed on plug 11. At the same time, spring 5 pushes sleeve 4 on top of said balls 9, thus locking plug 11 in position. As sleeve 4 and the associated slot or slideway 3 are moving, the engagement between a curve at the end of slot 3 and dowel 2 is disengaged with a consequence that lever 1 can be turned. During the first 15.degree. turn (FIG. 5), sleeve 4 slides forward in a manner that seal 6 closes the outlet passage 14 provided on body 10 with said ball 12 still remaining closed. As the swing or turn of lever 1 proceeds, said ball 12 begins to open and is fully open when lever 1 is parallel with the valve body (FIG. 6). During the turning motion of lever 1 between FIGS. 5 and 6, said sleeve 4 need not be displaced any longer but, instead, the dowel-slot deadlock 2, 3 serves to hold it in position. Disconnection of plug 11 is effected as follows. When lever 1 is turned towards the zero position shown in FIG. 3, ball 12 begins to close and is fully closed by the time said lever is 15.degree. away from the zero position (FIG. 5). As the turning proceeds, the dowel-slot combination 2, 3 displaces sleeve 4 rearwards to withdraw seal 6 from in front of outlet passages 14, whereby the pressure remaining in the outlet side hoses and working machines discharges through outlet passages 14 to atmosphere. Turning of lever 1 to the zero position shown in FIG. 4 does not yet release plug 11 but, instead, lever 1 must be turned e.g. 10.degree. further for allowing balls 9 to rise and spring 7 to push plug 11 out and to shove sleeve 13 under said balls 9 with a consequence that sleeve 4 is engaged in back-up position. When the grip is released from lever 1, said lever moves into the zero position, i.e. 90.degree. aside.