FR2852659A1 - Compression fitting for assembling PVC pipes, has protection ring interpolated between clamping ring and o-ring seal, and having groove with detent unit complimentary to detent unit set at latter ring in contact with former ring - Google Patents

Abstract

The fitting has a clamping ring (6) extending at an interior of a hollow body (2) and a screw (3) engaged on a threading at an exterior of the body. An o-ring seal (4) is lodged between the ring (6) and a shoulder. A protection ring (5) is interpolated between the ring (6) and seal. The ring (5) has a groove with a detent unit complimentary to a detent unit arranged at an end of the ring (6) in contact with the ring (5).

Description

15 Compression fitting

  The present invention relates to a compression fitting making it possible to assemble tubes, such as impact-modified rigid plastic tubes and in particular those made of impact-modified PVC or CPVC.

  A conventional compression fitting consists of a hollow body, generally made of plastic or metal, intended to receive at least one tube to be connected, and at least one nut which is screwed onto said hollow body. Inside the nut is arranged an annular seal as well as a split clamping ring ensuring the grip of the tube and the compression of the seal.

  International application WO / 02086371 has proposed a new type of compression fitting that is shorter than the previous ones and in which the ring and the seal are housed inside the hollow body of the compression fitting.

  The compression fitting nut has a projection on its end turned towards the tube, which becomes lodged during tightening between the ring and the body, so that the ring pushed back by the projection is compressed radially against the tube and axially against it. the seal, ensuring optimal sealing.

  When using such a compression fitting on a building site, there is however a risk of accidental separation of the constituent parts, or even the loss of the ring or of the seal. Furthermore, if these components fall to the ground, they may then become soiled, which may eventually lead to a leak in the assembly.

  The object of the present invention is therefore to propose a compression fitting of the type described above and of safer use, making it possible to hold in place in the body, the seal and the clamping ring. 20 To this end, the invention relates to a compression fitting of the type comprising at least one hollow body having on its outer wall, at at least one end, an external thread, a deformable clamping ring 25 extending to the inside the hollow body, at the threaded end thereof, a nut which can be screwed onto the thread outside the body and provided with a projection suitable for engaging between the internal face of the hollow body and the external face of the clamping ring when the nut is screwed onto the hollow body, an O-ring seal housed between the clamping ring and a shoulder formed in the internal face of the hollow body, characterized in that a seal protection and retaining ring is interposed between the clamping ring and the O-ring seal, said ring comprising a groove open towards the inside, said groove having a latching means complementary to a latching means m grooved at the end 5 of the clamping ring in contact with the ring, the snap-fastening of the ring on the ring allowing the retaining of the ring on the ring.

  Preferably, the protection and retaining ring has an external lateral face shaped to absorb the dimensional deviations of the hollow body of the compression fitting and to maintain the ring / ring / seal assembly whatever the position of the hollow body during of its manipulation.

  Thus, advantageously, when installing the compression fitting on a building site, the snap-fastening of the clamping ring on the protection and holding ring also makes it possible to keep said ring in the body of the fitting, the positioning this is done safely and without risk of loss of the clamping ring.

  The invention will now be described in more detail with reference to the drawings in which FIG. 1 is a sectional view of the compression fitting according to the invention; 2 shows an enlarged sectional view of the clamping ring and the protection and maintenance ring from the connector according to FIG. 1; Figure 3 shows a sectional view of the compression fitting according to an alternative embodiment of the invention; FIG. 4 represents an enlarged sectional view of the clamping ring and of the protection and maintenance ring coming from the connector according to FIG. 3 and FIG. 5 represents a sectional view of FIG. 3.

  The compression fitting 1 according to the invention comprises a hollow body 2 of plastic material of the polypropylene type and a nut 3 preferably made of polyacetal.

  The hollow body 2 has on its outer wall, at at least one end, an external thread while the nut 3 has an internal thread to cooperate with the external thread of the hollow body 2 during the screwing of the nut 3.

  Inside the hollow body 2 and at the end of it are housed an O-ring seal 4, a ring 5 for protecting the seal 4 and for holding it and a split clamping ring 6.

  The O-ring seal 4 is housed between the clamping ring 6 and a shoulder 2a housed in the internal face of the hollow body 2.

  The nut 3 is provided, at the internal outlet with a cylindrical part for introducing the tube to be connected, with a frustoconical part 3 'for connection to a projection 3a suitable for engaging between the internal face of the hollow body 2 and the external face of the clamping ring 6 when the nut 3 is screwed onto the hollow body 2 (see FIGS. 1 and 3).

  The ring 5 is substantially in the form of a polyacetal washer 5 provided at the end intended to be opposite the clamping ring 6, with a peripheral groove 5 ′ open towards the inside of the hollow body.

  This groove 5 ′ has a latching means 10 complementary to a latching means formed at the end of the clamping ring 6.

  This latching means consists of the inner side wall 5a of the groove 5 'which is arranged obliquely inward of the ring 5.

  The latching means can alternatively be produced by a step on this inner side wall Sa.

  The clamping ring 6 is generally metallic, split and notched internally to ensure by compression the maintenance of the tube to be connected.

  The end of the ring 6 intended to be snapped onto the ring 5 has a snap-on means complementary to that of the ring.

  This latching means is preferably constituted by the outer face of the ring 6 which extends obliquely 30 to cooperate with the oblique inner side wall Sa of the groove 5 'of the ring 5.

  As a variant, the external face of the ring 6 may have a step.

  The opposite end of the tightening ring 6 is generally made frusto-conical 6 'to cooperate with the frusto-conical part 3' of the nut 3.

  In the alternative embodiment, shown in FIGS. 3, 4 and 5, the hollow body 2 has a first bore 21 whose diameter corresponds to that of the O-ring 4, and a second bore 22, of greater diameter, intended to receive the ring 50 for protecting the seal and holding it.

  The ring 50 has substantially the same conformation as the ring 5 of Figures 1 and 2, but it also carries a skirt 51 15 intended to come to bear on the O-ring 4. Therefore, the outer diameter of the skirt 51 is less than the diameter of the first bore 21 of the hollow body 2 in order to allow the skirt 51 to be introduced without friction into the first bore 21 of the hollow body 2.

  Between the bores 21 and 22, the hollow body 2 has an annular surface 20 capable of playing the role of abutment for the lower annular wall 52 of the ring 50, to prevent excessive tightening of the nut 3 does not cause crushing of the O-ring 4 by the skirt 51 liable to damage the seal 4.

  When using a connector according to the invention, in the body of which has been previously inserted in each socket 30 an O-ring 4, a protection and holding ring 5 and a tightening ring 6, the tube is introduced. in the nut up to the stop 23 of the body 2 of the fitting and after passage of the seal then the nut 3 is screwed until it locks. During this screwing operation, the conical part 3 ′ of the nut tightens the clamping ring 6, split and notched on the tube and acts simultaneously in compression on the O-ring 4 via the ring 5.

  The plastic tube is scratched by the notches of the ring which constitutes as many retention zones opposing the accidental dislocation of the tube.

  Note also that the outer side face of the ring (5 50) is not cylindrical. In the embodiment of Figure 2, the side face 53 of the ring 5 is rounded, or curved, without sharp edges. In the example of FIG. 4, the lateral face 54 of the ring 50 is bitronconical. This non-cylindrical conformation of the outer lateral surface of the ring has a double function.

  First of all, it allows easy positioning of said ring in the hollow body 2 because it does not require it to be presented in a plane strictly perpendicular to the axis of the hollow body 2.

  Then, it makes it possible to ensure the locking of the ring in the hollow body 2 during handling of the connector.

  In fact during these vacuum manipulations, when the nut 3 is removed from the hollow body, a tilting of the hollow body having the effect of presenting the opening of the hollow body downwards causes by gravity a relative tilting of the assembly ring-ring with respect to the hollow body. During this relative tilting, the mean plane of the ring inclines relative to the axis of the hollow body and cannot be perpendicular to it. This relative tilting is authorized by the non-cylindrical shape of the outer surface of the compression ring. By this relative tilting, the ring is blocked in the bore of the hollow body after a pivoting of some 5 degrees. Thus it does not fall and retains the clamping ring 6 thanks to their reciprocal latching means. It also maintains the O-ring 4 inside the body of the fitting.

Claims (7)

  1. Compression fitting (1) of the type comprising at least one hollow body (2) having on its outer wall, at at least one end, an external thread, a deformable clamping ring (6) extending inside of the hollow body (2), at the threaded end thereof, a nut (3) which can be engaged by screwing onto the thread outside the body (2) and provided with a projection (3a) suitable for 10 to s '' between the inner face of the hollow body (2) and the outer face of the clamping ring (6) when screwing the nut (3) on the hollow body (2), an O-ring seal (4 ) housed between the clamping ring (6) and a shoulder (2a) formed in the internal face 15 of the hollow body (2), characterized in that a ring (5) for protecting the seal and holding it is interposed between the clamping ring (6) and the O-ring seal (4), said ring (5) comprising a groove (5 ') open inwards, said groove 20 (5') having a locking means additional uetting of a latching means arranged at the end of the clamping ring (6) in contact with the ring (5), the snap-fastening of the ring on the ring allowing the retaining of the ring on the 'ring.   2. Connection according to claim l, characterized in that the ring (5) is in the form of a washer and may further comprise a skirt (51).   3. Connection according to one of claims 1 and 2,   characterized in that the ring (5 50) has an external lateral face (53 54) shaped to absorb the dimensional deviations of the hollow body (2) of the compression fitting (1) and to maintain the ring / ring / seal assembly whatever the position of the hollow body during its handling.   4. Connection according to one of claims 1 to 3,   characterized in that the external lateral face (53) of the ring (50) is rounded or curved, without sharp edges.   5. Connection according to one of claims 1 to 3,   characterized in that the external lateral face (54) of the ring (50) is bitronconical.   6. Connection according to one of claims 1 to 5,   characterized in that the latching means of the ring consists of the vertical wall (5a) of the groove (5 ') which is made oblique towards the inside of the ring (5), the external face of the ring (6) extending obliquely to cooperate with said oblique vertical wall (5a).   7. Connection according to one of claims 1 to 6,   characterized in that the complementary latching means of the ring (5) and the ring (6) are respectively a step on the vertical wall (5a) of the groove of the ring (5) and a step on the outer face of the ring (6).