Bayonet connector assembly for a fluid line

Abstract: Connection of the bayonet type between a fluid line and a connecting member, comprising a fitting which can be connected to a fluid line and is provided with a substantially cylindrical insertion part, which is provided, at a distance from its axial end, with one or more locking projections which project outwards, and a connecting member which is provided with an insertion bore for accommodating the insertion part of the fitting. The connection member (8) is designed in such a manner that the insertion part (10), in its insertion position, can be fitted into the insertion bore (6), and then the fitting can be moved into a locked position with respect to the connection member by means of relative rotation, so that the fitting is secured against being pulled out of the insertion bore.

Description: The present invention relates to a bayonet connector assembly for establishing a connection between a fluid line and a connecting member, in particular a connection between a hydraulic pressure line and a hydraulic component, such as, for example, a hydraulic cylinder, a hydraulic pump or a valve block. Such a bayonet connection between a fluid line and a connecting memeber is generally known, for example from EP 0 375 666. This known bayonet connection has the drawback that it is undesirably complicated to produce. This is because in this known bayonet connection slots are formed in the connecting member for receiving the diametrally opposite locking projections of the fitting arranged on the fluid hose. These slots lie along the insertion bore and each have a first slot part which extends in the insertion direction and is adjoined by a second slot part which is blind and extends at right angles to the insertion direction. Forming slots of this nature in the object member causes the cost price to become undesirably high. The present invention aims to eliminate the abovementioned drawback and, in particular, to provide a bayonet connection which can be achieved at considerably less expense than the known connection. The invention also aims to provide a right-angled connection between a fluid line and an object, wherein the fluid line projects to the minimum possible extent beyond the object. The present invention provides a bayonet connector assembly according to claim 1. The invention therefore provides for arranging a recess in the connecting member, e.g the gland of a hydraulic cilinder, and fixing a cap, which is to be produced separately, in the said recess. The cap and the recess are preferably of circular design. The cap can be easily and reliably fixed to the connecting member by providing the cap with an outwardly projecting attachment flange and clamping this attachment flange in by pressing the surrounding area of the connecting member over it. The cap is easy to produce. For example, it is possible to produce the cap using the known metal injection-moulding process. The fitting which is to be attached to the fluid line can also be produced using this same process. Further advantageous embodiments of the invention are described in the claims and in the following description, in which the invention will be explained in more detail with reference to the drawing, in which: Fig. 1 shows a diagrammatic, perspective view of the components of a first exemplary embodiment of the bayonet connector assembly according to the invention, in an application in which a hydraulic hose is being connected to the gland of a hydraulic cylinder, Fig. 2 shows a partial longitudinal section through the gland of a hydraulic cylinder and a right-angled hose fitting in accordance with Fig. 1 which is connected thereto, Fig. 3 shows a view which corresponds to that shown in Fig. 2 of a second exemplary embodiment of the bayonet connection according to the invention. Figures 1, 2 and 3 show a metal gland 1 also known as end cover of a linear hydraulic cylinder, only part of which is shown in Figure 1. The gland 1 is attached in a suitable manner to the cylinder tube 2 of the cylinder and has a central axial bore 3 through which the piston rod 4 of the cylinder fits. A bayonet connection is used to connect the piston-rod-side working chamber of the cylinder to a hydraulic hose 5. For this purpose, an insertion bore 6, which in this case is at right angles to the central bore 3, is formed in the gland 1. The insertion side or entrance of the insertion bore 6 lies on the cylindrical outer surface of the gland 1. The hydraulic hose 5 is provided with a metal right-angled fitting 7 having a hose connector body 8 to which the hose 5 is fixed in a manner known per se using a sleeve 9 which is crimped on the hose 5. A substantially cylindrical insertion part 10 of the fitting 7 adjoins the hose connector body 8, the insertion part 10 being directed at right angles to the hose connector body 8. At a distance from the free end of the insertion part 10, there is a groove in which a sealing ring 11 is accommodated. Two locking projections 12 which project diametrally outwards with respect to the insertion part 10 are formed on the fitting 7 at a greater distance than the groove of the sealing ring 11 from the free end of the insertion part 10. Preferably, the fitting 7 is produced using the metal injection-moulding process, so that the fitting 7 has a unitary metal body. A production process of this nature is particularly preferable if the dimensions of the fitting 7 are small. The gland 1 is provided, on the insertion side of the insertion bore 6, with a circular recess 15 which has a circumferential surface 16 and an annular base surface 17, the base surface 17 forming the transition between the circumferential surface 16 of the recess 15 and a part of the insertion bore 6 which has a diameter which is matched to the diameter of the insertion part 10. This latter diameter of the insertion bore 6 is such that the sealing ring 11 fits in with the appropriate sliding fit desired for a liquid seal. A circular cap 20 which is provided with a passage opening 21 for the fitting 7 provided with locking projections 12 is fixed in the recess 15. In this case, the base surface 17 of the recess 15 and the opposite underside of the cap 20 form a chamber. The passage opening 21 and this chamber are such that it is possible for the fitting 7, in its insertion position which is shown in Figure 1, to fit into the insertion bore 6 until the locking projections lie below the level of the underside of the cap 20, and then for the fitting 7 to be rotated through a quarter turn into a locked position thereof, in which the locking projections 12 are covered by the cap 20 and the fitting 7 cannot be pulled out of the insertion bore 6. In this case, the cap 20 has an annular wall 23 with an external diameter which is smaller than the diameter of the recess 15 and an internal diameter which is greater than the diameter of the fitting 7 at the level of the locking projections 12. An outwardly projecting attachment flange 24, the thickness of which is less than the depth of the recess 15 in the gland 1, is provided on the underside of the annular wall 23. The attachment flange 24 is clamped in between the base surface 17 of the recess 15 and parts of the edge region, lying around the recess 15, of the gland 1 which are pressed over the attachment flange 24. For this attachment, it is preferable for an annular ram to be placed on the said metal annular region of the gland 1 and then for a considerable pressure to be applied, so that the edge region of the gland 1 which projects above the attachment flange 24 of the cap 20 is plastically deformed and pressed over the attachment flange 24. The cap 20 furthermore has an end wall 25 which spans the top side of the annular wall 23 and is provided with the passage opening 21 for the fitting 7. The cap 20 is preferably made from metal using the metal injection-moulding process. Figures 2 and 3 furthermore show an annular spring 30 which can be compressed elastically in the insertion direction and bears against the base surface 17 of the recess 15. The spring 30, which is preferably formed from a thin strip of spring steel which is suitably corrugated, serves to press the locking projections 12 of the fitting 7, especially in the locked position, towards the underside of the cap 20. In this case, a securing recess 31, into which the locking projection 12 moves, under pressure from the spring 30, in the locked position of the fitting 7, is formed on the underside of the cap 20 for each locking projection 12 of the fitting 7. Preferably, the spring 30 is enclosed between the cap 20 and the gland 1. The embodiment shown in Figure 3 differs from the design shown in Figure 2 only by the fact that the distance between the locking projections 12 and the hose connector body 8 of the fitting 7 is shorter than in Figure 2. This distance is such that, in the fitted position, the hose connector body 8 virtually bears against the top side of the cap 20, the slight clearance serving to allow the fitting 7 to be pressed slightly into the insertion bore 6 counter to the spring force, in order to be able to release the locking projections 12 from the securing recesses in the cap 20. As a result, a hydraulic hose which is to be connected to the right-angled fitting 7 lies close to the cylinder in the longitudinal direction, so that the complete assembly does not take up much space. It will be clear that it is also possible for the annular gland 1 to be provided, at the location of the insertion bore 6, with a recess in the form of a shallow flat instead of a circular recess. In this case too, a suitably shaped, substantially rectangular cap can be fixed on by pressing the adjoining edge regions of the gland 1 over the cap. If the cap 20 is designed to be slightly elastically deformable, the spring 30 can be dispensed with. In this case, the above-described securing action of the cap 20 can be obtained if the chamber between the cap 20 and the base surface 17 is slightly smaller than the thickness of the locking projections 12, so that the cap 20 has to expand outwards in order to allow the locking projections to move past when the fitting 7 is rotated into the locked position. In another embodiment of the bayonet connection according to the invention (not shown), the cap is of rigid design and the locking projections of the fitting are of elastic design, so that in the absence of the spring described here the locking projections are deformed elastically when the fitting is rotated into the locked position, so that the fitting is secured in this position.

Claims: Bayonet connector assembly for connection of a fluid line, said connector assembly comprising a fitting (7) which is connectable to a fluid line and is provided with a substantially cylindrical insertion part (10), said insertion part (10) having at a distance from its axial end one or more locking projections (12) which project outwards, said connector assembly further comprising a connecting body which is provided with an insertion bore (6) for receiving the insertion part (10) of the fitting, the connecting body being adapted for receiving the insertion part of the fitting (7) in an insertion position thereof relative to the connecting body and for a subsequent relative rotation of the fitting with respect to the connecting body into a locked position of the fitting, so that the fitting is secured against being pulled out of the insertion bore, the connecting body being provided, at the entrance of the insertion bore (6), with a recess (15) which has a circumferential surface and an annular base surface (17), the internal dimension of the circumferential surface (16) being greater than the diameter of the fitting at the level of the locking projections (12), and the base surface (17) forming a transition between the circumferential surface of the recess and a part of the insertion bore (6) which has a diameter which is adapted to slidingly receive the insertion part (10), characterised in that a cap which fits into the recess is fixed in the latter, which cap is provided with a passage opening for the fitting provided with locking projections, the base surface of the recess (17) and the opposite underside of the cap delimiting a chamber which allows the fitting to be rotated into the locked position in which the locking projections (12) are covered by the cap. Connector assembly according to claim 1, in which the base surface of the recess and the underside of the cap, at at least one position, define a narrowed section in the chamber with a passage cross section which is smaller than the largest dimension of that section of a locking projection of the fitting which moves past the said narrowed section when the fitting is being moved into the locked position, the cap being elastically deformable in order for the locking projection to move past the narrowed section. Connector assembly according to claim 1, in which the distance from the base surface to the underside of the cap is such that it is possible for the locking projections to move past without hinderance when the fitting is being moved into the locked position, and in which connection an elastically compressible spring member is situated in the chamber, which spring member, in the mounted position of the connection, lies between the base surface and the locking projections and presses the locking projections towards the underside of the cap. Connector assembly according to claim 2 or 3, in which a securing recess is provided on the underside of the cap for each locking projection, for the purpose of accommodating the locking projection in the locked position of the fitting. Connector assembly according to claim 3, in which one or more securing elevations, which are directed towards the base surface, are provided on the underside of the cap for each locking projection, which securing elevations, in the locked position of the fitting, secure the locking projection so that it cannot rotate. Connector assembly according to one or more of the preceding claims, in which the cap is attached in the connection member by deforming parts of the connection member which lie around the cap. Connector assembly according to claim 6, in which the cap has an annular wall with an external diameter which is smaller than the diameter of the recess and an internal diameter which is greater than the diameter of the fitting at the level of the locking projections, an outwardly projecting attachment flange, the thickness of which is less than the depth of the recess in the connection member, being provided on the underside of the annular wall, and the attachment flange being clamped in between the base surface of the recess and those parts of the connection member which are pressed over the attachment flange, and the cap furthermore having an end wall which spans the top side of the annular wall and is provided with the passage opening for the fitting. Connector assembly according to claim 3, in which the spring is clamped in between the cap and the base surface of the recess. Connector assembly according to one or more of the preceding claims, in which the fitting is a right-angled fitting with a hose connector body and the insertion part directed at a right angle thereto, the distance between the locking projections and the hose connector body being such that, except for a slight clearance, the hose connector body lies along the top side of the cap in the locked position of the fitting.

Inventors: VAN MEERVELD MARTEN, VAN MEERVELD, MARTEN
Applicants: ACTUANT CORP, ACTUANT CORPORATION
Application year: 1999
Main classification: F16L37
IPC codes: F16L37