FR2485686A1 - Pipe joint with spherical bearing faces - uses captive slidable rotatable nut sleeve to pull pipe end onto end pipe fitting with barrel thread - Google Patents

Abstract

The screwed pipe joint may be used on gas pipes, using axial compression on part spherical bearing (1b,2b) surfaces to provide the seal. A female pipe fitting (1) provides a concave annular bearing surface (1b) with the mating surface (2b) provided on male fitting (2), the terminal barrel length of the female fitting being threaded (1c), and the male fitting locating a captive axially slidable rotatable nut (4). A rectangular section ring (3) in a barrel groove (2c) is engaged by an internal circumferential rib (4a) to prevent the nut from escaping. The ring is open (3a) and may be force fitted into the groove after the nut is threaded on the male fitting.

Description

IMPROVED CONNECTION WITH SPHERICAL RANGE
AND CONSTITUENT PIECE
The invention relates to an improved spherical bearing connection and extends to the component parts of this connection. It can in particular be applied to make connections for gas pipes.

 It is known that the advantage of spherical fittings is to provide excellent sealing in the absence of an O-ring. In known spherical bearing connections, the movable clamping nut which is associated with one of the parts abuts against a shoulder machined around the periphery of this part, to allow clamping; in most connections, this nut can not be engaged by the rear part of the fitting (larger diameter of this part, elbow fitting, etc ...) and the nut must be crimped around this piece.

 These connections have a serious disadvantage, resulting from the crimping of the nut which causes a weakening thereof on the mechanical level, with the risk of formation of microcracks in the working area of the material. It follows that the clamping force that can accept such connections is limited.

 The present invention proposes to remedy this drawback.

 An object of the invention is in particular to provide improved fittings spherical scope, able to admit much higher forces and, consequently, to condition a better seal at the spherical bearings.

To this end, the present invention relates to a coupling comprising two conjugate parts, a first part provided at one end with an external thread and with a spherical, concave or convex ring-shaped bearing, and a second piece provided with one end of a movable nut with a threaded tapping of the thread of the first piece and a spherical, convex or concave ring-shaped bearing surface co-nested with the spherical bearing surface of the first piece. According to the present invention, the second piece is provided at the rear of its scope with an annular groove in which is inserted a ring #
reported / projecting partially from said groove, the movable nut being adapted to abut against said ring by a rear heel which it is provided.

 According to another characteristic of the invention, the insert ring is open in an area of its periphery to be inserted into force in the corresponding groove by the play of its elasticity; in addition, the nut is a neck nut set up around the second piece before the insertion of said ring.

 This removes all the disadvantages related to crimped nuts. -The décolleté nut which is engaged, by the front, around the second part, before positioning the ring which will serve as a stop, has a mechanical strength much higher than that of nuts crimped because its material has not suffered internal stresses from crimping; this nut is thus able to withstand much higher clamping forces.

 The invention extends to the constituent elements of the coupling described above and in particular to a connecting piece, regardless of its shape, comprising, at the rear of its spherical bearing, on the one hand, an attached ring, projecting partially from an annular groove in said part, on the other hand, a movable nut provided with a heel adapted to abut against said ring.

The description which follows, with reference to the appended drawing, presents, by way of illustrative example, an embodiment of the invention; on this drawing
FIG. 1 is a view in longitudinal section of the two parts of a coupling according to the invention, in disassembled position,
FIG. 2 is a cross-section through a plane AA of one of the parts,
Figure 3 is a partial longitudinal section showing the fitting mounted, with a view of an enlarged detail.

 The connector shown by way of example in the figures is intended for gas pipes and is made of a metal such as cupro-aluminum alloy, brass or steel.

 It consists essentially of two conjugate parts 1 and 2, called to be brazed or welded by their rear part la and 2a on the conduits to be connected.

 The first piece 1, made by bar turning, comprises at its front end, an external thread lc and a concave spherical bearing lb, moreover, it is provided with an external part with cut sides ld for its maintenance during my tax.

The second piece 2, also made by bar turning, comprises at its front end a convex spherical bearing 2b, conjugate of the bearing 1b, and an outer annular groove 2c, in the example of rectangular cross section. In this groove, is disposed a ring 3, open in-3a on its periphery, so as to allow to engage around the piece 2, # to introduce it into the groove 2c e
In addition, a nut 4, made by bar turning with a rear bead 4a, is associated with the part 2. This nut provided with a tapping 4b is engaged from the front around the part 2, before the insertion of the ring. 3-in his throat.

 This nut can thus be implemented regardless of the shape of the rear portion 2a of the part 2, without crimping operation. Under these conditions, it has a high mechanical strength, making it able to withstand significant tightening forces.

 Figure 3 illustrates the mounted fitting; when tightening, the heel 4a of the nut 4 abuts against the ring 3, projecting partially from the groove 2c, and makes it possible to apply the metal spherical bearings 1b and 2b against each other with a high pressure. , in order to obtain a good seal of the connection.

 Of course, the invention is not limited to the terms of the foregoing description, but includes all variants thereof. In particular, it applies as well to the case where the parts 1 and 2 are welded or soldered to the elements to be connected, that in the case where these parts are an integral part of these elements, the spherical bearing surfaces lb, 2b, threading lc. and groove 2c being machined thereon.

 In addition, a preferred embodiment has been described in which the movable nut 4 is associated with the part 2 provided with the convex spherical bearing surface 2b; it is understood that the invention extends to the opposite case where the movable nut is associated with a part provided with a concave bearing, this part being provided with a groove and a ring similar to those described.

Claims (6)

 1 / - spherical fitting, comprising firstly a first part (1) endowed at one end with an external thread (lc) and a bearing surface (1b) in the shape of a concave or convex spherical ring, on the other hand, a second piece (2), conjugated with the first and endowed at one end with a movable nut (4) with a threaded tapping thread (lc) of the first and a bearing surface (2b) shaped of a spherical ring, convex or concave, conjugated with the spherical bearing (lob), said coupling being characterized in that the second piece (2) is provided at the rear of its bearing with an annular groove (2c), in which is inserted an insert ring (3) projecting partially from said groove (2c), the movable nut (4) being adapted to abut against said ring (3) by a rear heel (4a) which it is provided.  2 / - spherical fitting according to claim 1, characterized in that the ring (3) is open in a zone (3a) of its periphery and is inserted into force in the groove (2c) by the play of its elasticity.  3 / - spherical fitting according to one of claims 1 or 2, characterized in that the nut (4) is a neck nut, placed around the second piece (2) before the insertion of the ring (3).  4 / - spherical fitting according to one of claims 1 2 or 3, wherein the second part (2) provided with the nut (4) has a convex spherical bearing surface (2b), and the first piece (1) provided with the thread (lc) has a concave spherical bearing (lb).  5 / - spherical fitting according to one of claims i 2, 3 or 4, for gas pipe, made cupro-aluminum alloy, brass or steel.  6 / - Spherical coupling piece according to one of the preceding claims, characterized in that it comprises, at the rear of its spherical bearing surface (2b), an attached ring (3) projecting partially from an annular groove (2c) formed in said piece, and a movable nut (4) provided with a heel (4a). adapted to abut against said ring (3).