The invention relates to a coupling for connecting hoses or the like for a medium under pressure in accordance with the preamble to Claim 1.

Detachable couplings for connecting hoses or the like for pressure media are used extensively in industry and handicrafts, especially couplings for compressed air. Such couplings are often used for connecting a compressed air tool or the like to a compressed air source. The female part of the coupling has a valve element which makes it possible to keep the hose leading to the female part continuously under pressure. The nipple of the coupling is connected to a hose or the like which leads to a compressed air tool. When changing tools or detaching the tool from the compressed air source for some other reason, there is often relatively high pressure there. When the nipple is disconnected from the female part, there is powerful recoil throwing the nipple in the hose connected thereto. There is also a loud noise at disconnection. Both the recoil force and the sound are disadvanta¬ ges which should be removed for,among other things, reasons of safety.

The purpose of the present invention is to achieve a coupling of the type descri- bed by way of introduction which removes the above mentioned disadvantages and makes possible disconnection of the nipple from the female part while the coupling is under pressure, without any recoil or noise.

This is achieved according to the invention by means of a coupling which is characterized by the features disclosed in die characterizing portion of Claim 1.

Suitable embodiments of the coupling according to the invention are disclosed in the subclaims.

The invention will be described in more detail below with reference to the accompanying drawing, in which

Figure 1 shows a longitudinal section through a coupling according to one embodiment of the invention in its connected state, Figure 2 shows the coupling according to Figure 1 at the beginning of the disconnecting process, Figure 3 shows the coupling of Figures 1 and 2 in an intermediate position during a disconnecting process, and

Figure 4 shows the female part of the coupling shown in Figures 1-3 after disconnection of the nipple.

The coupling shown in the drawing comprises a female part 1 and a nipple 2 insertable therein. The female part 1 is provided with an attachment means 3 for a hose or a pipe, and the nipple 2 is provided with attachment means 4 for insertion into a hose. The female part 1 is intended to be connected to a pressure medium source (not shown) while the nipple 2 is intended to be connected via hose to a tool or the like (not shown).

A ball lock means of a type known per se widi a number of balls 5 distributed about the periphery and disposed in radial openings in the female part 1 and cooperating with a circumferential groove 6 in the nipple, is arranged in the vicinity of the free end of the female part 1. The functioning of this ball lock means is well known and the ball lock means is used to lock the nipple 2 in its inserted position in the female part 1 , as shown in Figure 1. The balls 5 are kept pressed into the groove 6 by means of a ring 7, which is axially movable along the outside of me female part 1 and which is biased by means of a spring 8 towards the locking position shown in Figure 1.

The nipple 2 is hollow and keeps a valve element 9, in the position shown in Figure 1 , spaced from a valve seat 10 within the female part 1. The valve element 9 is provided for this purpose with a hollow extension 11 which is provided with radial openings adjacent the valve element proper 9 to make possible flow of medium through the coupling. In this position shown in Figure

1 , the nipple 2, via the extension 11 has moved the valve body 9 away from the valve seat 10, by compressing a spring 12.

The extension 11 is provided at its outer surface with a peripheral groove 13, into which there extends a shoulder 14 at one end of an arm 15. The drawing shows only one arm 15, but in practice the female part 1 is provided with a plurality of such arms spaced circumferentially. At the end of the arm 15 remote from the shoulder 14 there is a rounded projection 16, which in the engaged position shown in Figure 1 extends into the groove 6 in the nipple 2.

In the position shown in Figure 2, a disengaging process has just began. A sleeve 17, which is biased by a spring 18 to the coupled position shown in Figure 1 , has been moved away from the free position of the female part 1. The ring 7 has followed the sleeve 17 against the force of its spring 8, so that a a bevelled end of the ring 7 cooperates wim the balls 5. In this position, the balls 5 can move radially outwards and thus press the ring 7 further backwards against the force of the spring 8. A projection 19 on the sleeve 17 abuts against die radially outer surface of the arm 15 and keeps it in engagement wit die groove 6 in me nipple 2.

When die nipple 2, as a result of the force of die spring 12 is pressed by die extension 11 of the valve element 9, axially out of die female part 1 , me balls 5 will be pressed radially outwards from the groove 6 by virtue of the fact that the edges of the groove 6 are oblique. The nipple 2 is tiiereby freed to move axially out of die female part 1 until it reaches die position shown in Figure 3. In tiiis position the valve element 9 has been moved into sealing engagement widi die valve seat 10, so that no flow of medium is possible through me female part 1. The arm 15 is however, retained widi its projection 16 extending into the groove 6 because the projection 19 on die sleeve 17 will not permit the arm 15 and its projection 16 to move radially outwards. The nipple 2 is thus held in an in¬ termediate position. Pressure medium in the nipple 2 and in the hose connected

thereto can thus exit through the gap between the extension 11 of the valve element 9 and the female part 1 into the surroundings. The pressure in the nipple

2 providing the axial force on the nipple 2 away from the female part 1 drops of course. This force exerts a radially outwardly directed force on the projection 16 and the arm 15. The arm 15 is provided with a depression 20 with oblique edges, into which the projection 19 of the sleeve 17 extends. The radially outwardly directed force on the arm 15 holds die sleeve 17 in d e position shown in Figure

3 until the internal pressure in die nipple 2 has dropped to a predetermined level. When this level has been passed, the force on the spring 18 will overcome me radially outwardly directed force on me arm 15, so that the projection 19 can be moved out of the depression 20. The spring 18 can thereafter displace the sleeve 17 to the position shown in Figure 4, in which the arm 15 can pivot radially outwards to mus free me nipple 2 for removal from the female part 1.

The process described above enables the nipple 2 to be removed from the female part 1 in a controlled and satisfactory manner even if the interim pressure in me coupling is relatively high. In summary, it can be said that the nipple 2 is first moved to an intermediate position, in which the valve element 9 seals against me valve seat 10, whereafter the internal pressure on e nipple 2 and the portions connected thereto will be allowed to drop in a controlled manner by releasing to the surroundings. When die internal pressure has dropped to a certain level, which can be determined by suitable dimensioning of die components, the nipple 2 is released for removal from die female part 1. In this manner, bodi noise and the powerful recoil are avoided, which means that the disengagement can be done in a satisfactory manner as regards safety and convenience.

The invention is of course not limited to the embodiment described above. However, it can be modified widiin the scope of the attached patent claims.