FR2516615A1 - Coupling for two tubes - has two sets of curved blades with alternative, offset curvatures to aid assembly - Google Patents

Abstract

The coupling consists of a split ring (1) from which extend a series of longitudinal blades. The blades are cranked into a concave form. The peaks of the curved surfaces of the baldes are staggered so that alternate blades have their peaks at one position (N2) and the others at a second position (N1) along their lengths. The ends (3) of the blades are curved inwards to facilitate the insertion of the coupling into an outer tube. The coupling is fixed to the tube by the lugs (5). When the second component or rod is inserted into the coupling it meets resistance in two distinct stages. However the normal full force will be required to disengage the coupling.

Description

 The present invention relates to a coupling device of two parts allowing a reduction of the efforts of introduction of the male part into the female part.

 In the coupling devices making it possible to join a male part and a female part in a non-definitive way, it is difficult to achieve a satisfactory compromise between the need to ensure a solid fixing of the parts with respect to each other and that of allowing easy introduction without long and / or complicated manipulations. The device according to the invention proposes to provide a satisfactory response to these often contradictory requirements by allowing a significant reduction in the insertion forces while retaining sufficient resistance to extraction to ensure a solid coupling.

 To do this, it comprises an intermediate coupling element mounted on one of the parts to be assembled and consisting of flexible curved blades fixed by one of their ends around a collar so that the centers of curvature of said blades are distributed alternately on at least two levels by delimiting the cross sections constituting the active parts for applying the pressure forces of the flexible blades on the second part to be assembled.

The description which follows, with reference to the appended drawings, will allow a better understanding of the invention
- Figure 1 is a view of the element according to the invention.

 - Figure 2 is a section of said element.

 - Figures 3 and 4 show two possibilities of coupling using an element according to the invention.

 A piece 1 (freeze 1) in the form of a collar is provided with flexible blades 2 and 3 distributed axially around said collar. The blades 2 have a curvature whose center is located at a level N2 of their height; similarly the center of curvature of the blades 3 is located at a level N1 distinct from the first. The blades 2 and 3 alternate around the collar so as to form two narrowed cross sections, at the level of the levels Ni t N2, on which the pressure forces are applied. In the example chosen, the curvature of the blades is concave so as to cooperate with a male part 4 (fig. 3). To do this, the collar 1 is provided with fixing lugs 5 used to make the device integral with the female part 6 to be coupled.

The blades are disposed axially in elastic support along the internal wall of the part 6 by the action of their convex free end on said wall. The male part 4 engages in the middle of the blades by overcoming a first resistance created at level N1 by the blades 3, then a second resistance created at level N2 by the blades 2, the total effort necessary to mating. On the other hand, at the extraction the two levels act simultaneously and one thus preserves a sufficient resistance to prevent an untimely uncoupling.

An alternative embodiment is shown in FIG. 4, in this case, the coupling element is made integral by means of the tabs 7 of the male part 8 to be coupled. The flexible blades 9 and 10 are provided with convex curvatures and extend axially along the external wall of the male part 8 on which their concave free ends are in elastic support and exert a pinching effect. The assembly is engaged in the female part 11 on the internal wall of which it exerts a first force at level N1 then a second at level N2 as above.

 The examples which have been described relate to a system with two levels of force, of course, and without departing from the scope of the present invention, it is possible to design systems with multiple levels, the introduction force being , each time divided by the number of these levels.

Claims (3)

 1 - Device for coupling two parts allowing a reduction in the forces of introduction of the male part into the female part,  Characterized in that it comprises an intermediate coupling element mounted on one of the parts to be assembled and consisting of flexible, curved blades, fixed by one of their ends around a collar so that the centers of curvature of said blades are distributed alternately on at least two levels delimiting cross sections constituting the active parts for applying the pressure forces of the flexible blades on the second part to be assembled.  2 - Device according to claim 1,  Characterized in that the intermediate coupling element is introduced axially along the internal wall of the female part to be coupled and that the flexible blades have a concave curvature determining on at least two levels the cross sections acting under pressure on the engaged male part inside the space delimited by said blades.  3 - Device according to claim 1,  Characterized in that the intermediate coupling element is arranged axially along the external wall of the male part to be coupled and that the flexible blades have a convex curvature determining on at least two levels of the cross sections acting under pressure on the part female in which they are engaged.