Patent ID: 12258986

DETAILED DESCRIPTION OF EMBODIMENTS

In the embodiment described hereafter, reference is made to an insertable clamp intended mainly for the temporary assembly of at least two drilled parts, of plate type, in the aeronautical and space industry. This non-limiting example is given for better understanding of the invention and does not exclude its use on other types of structures in related industries such as the automobile industry.

In the remainder of the description, the term “clamp” is used to designate an insertable clamp for the temporary assembly of drilled structures.

FIG.3shows in sectional view a clamp100including a main body10, wherein operates a major portion of the actuation mechanism of the clamp, a central part20, coaxially inserted inside the main body and rotationally locked in relation thereto, a clip30, passing through the central part and extending outside of the main body along its longitudinal axis X, a spreader40, fixed in relation to the main body and making it possible to open the clip when the mechanism of the clamp is actuated, a driver nut50, actuating said mechanism by a rotation about the longitudinal axis of the main body, and a spring60, placed inside the main body and providing a permanent alignment of the clip30with the longitudinal axis of said body as explained further.

The clamp100makes it possible to temporarily assemble at least two drilled parts200aand200b, by pressing them firmly against one another, by the compression of said parts between the main body10and the clip30, said clip passing through aligned holes produced in said parts. The resulting compressive stress is controlled by the tightening of the clamp.

The main body10, with reference toFIG.4, is tubular, has a roughly cylindrical shape with circular base and includes at one of its ends, so-called “front end” because intended to come into contact with the parts to be assembled, a collar11fastened in a housing12of said body, said housing being shaped to also receive the central part20and rotationally lock it. The housing12includes to this end a shape capable of translationally and rotationally locking the collar11and the central part20. Thus, in the example inFIG.4, the housing12comprises peripheral notches121machined in the bore13of the body, of prismatic shape and each having a base122defined by the removal of material on the bore. Furthermore, each notch121has an axis substantially parallel to the longitudinal axis X of the main body10. Therefore, the notches121make it possible to translationally guide the collar11and the central part20during their insertions into the housing12of the main body10, while making it possible to insert other elements of the clamp into the main body10, by the front end. The housing12may have other shapes making it possible to rotationally lock the collar11and the central part20, by means of lobes or ribs, hollow or protruding in relation to the bore of the main body. The translational locking may be performed for example by a wall extending perpendicular to the longitudinal axis X, occasionally distributed or in the form of a continuous shoulder, or by the addition of an elastic element elastically engaged in a recess produced in the bore of the main body, and radially extending inwardly over a sufficient distance in order to obstruct the central part20and provide its translational locking.

The central part20is also translationally immobilized along the axis X, abutting against the bases122of the notches121and a rear face of the collar11.

The collar11may for example be interlocked by clipping or clicking together at the end of the main body10, and defines an annular and preferably flat bearing surface111, in order to improve the contact with the parts to be assembled.

The central part20, with reference toFIG.5, has a polygonal flat shape, preferably regular, whereof the number of vertices21, materialized by corners, corresponds to the number of notches121of the housing12arranged in the main body10. Thus, each corner21comes to rest on the base122of a notch121so as to perform an interlocking between the central part20and the main body10. This mounting makes it possible to rotationally lock the central part20in relation to the main body10, with an improved stability while limiting the wear of the surfaces in contact, as opposed to a locking on a smooth bore without notches.

In the example of embodiment illustrated, the central part20has a regular hexagonal outer shape and comprises a through-hole23making possible the passage of the clip30.

The central part20further includes a diametrical groove24that makes it possible to rotationally immobilize the spreader40, said spreader having a T-shape. The groove24is produced on a front face25of the central part20and extends perpendicular to the longitudinal axis X. The central part20also has a bearing surface26opposite the front face25.

The clip30, according to the example of embodiment illustrated, is of elastic nature and includes a threaded end31initially placed inside the main body10, two branches32each of which ends with a protruding rounded end33, the two rounded ends33forming a hooking spur, hereafter referenced33.

The threaded end31, shown in sectional view inFIG.3, has a hollow cylindrical shape, open at one end and closed by a bottom at the opposite end, and includes a thread311on its outer lateral surface. The open end defines an annular edge312, whereon rests a washer72. The washer72has an outside diameter less than the inside diameter of the main body10, and an inside diameter sufficient for making possible the passage of the branches32of the clip30. The washer72is thus capable of sliding into the body10.

The threaded end31holds the two branches32so that they are embedded at the bottom and elastically free at the opening of said threaded end. To this last end, each branch32of the clip30has a local concavity321opposite the lateral wall of the threaded end31so as to define a spacing between said wall and the branches32at rest, for a mobility of said branches when moving them apart.

Each branch32of the clip30is turned back from its local concavity321and extends, along the axis X of the main body10, until the hooking spur33.

The hooking spur33, as highlighted above, consists of two rounded ends of the branches32, each of said ends has a flat face, the two flat faces are applied against one another when the clip30is closed (position at rest), and spaced apart when the clip is open (constrained position). The hooking spur33has a hooking surface331at its junction with the branches32, said surface is intended to come into contact with the parts to be assembled when the clamp100is sufficiently tightened. This hooking surface331is annular and, preferably, flat to avoid damaging the surfaces on contact.

The two branches32of the clip30are spaced apart, both at rest and when constrained, and define a slot34wherein the spreader40is placed.

The spreader40, with reference toFIG.6, is a T-shaped rod including a longitudinal portion41and a transverse portion42. The longitudinal portion41has a length less than the length of the branches32of the clip30and is disposed in the slot34between said branches. The transverse portion42is for its part placed in the diametrical groove24of the central part20so that it is rotationally locked, to the nearest functional clearance, in relation to said part and, thereby, in relation to the main body10.

FIG.7shows in front view the spreader40in place in the central part20, the transverse portion42being introduced into the diametrical groove24.

The spreader40, fixed in relation to the main body10, makes it possible to open the clip30by moving the branches32apart from one another when exposed to a movement, more specifically a removal, of said clip in relation to the main body. This movement is produced by the actuation of the driver nut50that constitutes the member for controlling the clamp100.

The driver nut50, according to the example of embodiment illustrated, has a roughly cylindrical shape with circular section of varying diameter, the diameter being larger at the free end of the driver nut, which corresponds to a manual gripping zone by the user, in order to reduce the tightening or at the very least pre-tightening force necessary before using tools. This varying section defines a recess52upstream of the main body10, between the free end of the driver nut and its opposite end translationally locked inside said body. Indeed, the driver nut50is mounted, in the main body10, rotationally free about the longitudinal axis X of said body while being translationally locked between an abutment71and the flaps of the main body10that come to latch on a shoulder of the recess52. Thus the driver nut50and the main body10are mounted in pivot connection of axis X. The driver nut has a constant overall length out of the main body, which speeds up the installation of a plurality of clamps on a structure or a drilling grid by a robot, the latter not having to identify any obstacles or modify its path to avoid them. Furthermore, the abutment71may advantageously constitute a sliding member in order to facilitate the rotation of the driver nut50in the main body10.

The driver nut50mainly includes a tapped bore51provided with an internal thread511for cooperating with the threaded end31of the clip30. Indeed, the rotation of the driver nut50produces a screwing or an unscrewing, according to the direction of said rotation, of the clip30in the bore51of said driver nut. In addition the threaded end31of the clip30is held engaged in the bore51by means of the spring60, placed around the branches32between the central part20and the annular edge312of said threaded end as shown inFIG.3.

The driver nut50includes at its closed end an indentation53adapted to receive the clip of another clamp. Indeed, when a plurality of clamps are transported by a pipe one behind the other, as shown inFIGS.10and11, the indentation53makes it possible to center the clamps in the pipe.

According to the example of embodiment illustrated, the indentation is a cone of angle α, for example 120°, and of axis substantially identical to the longitudinal axis X of the clamp. The shape of the indentation may vary in order to adapt to other shapes of clips.

The spring60is disposed in the main body10between the central part20and the washer72. The spring60is advantageously a compression spring permanently exerting a force along the longitudinal axis X tending to push back the clip30, via its threaded end31, in the direction of the removal, namely towards the bore51of the driver nut50, when said end is not totally introduced into said bore. This force also has the advantage of centering and engaging the threaded end31at the entrance of the tapped bore51. This has the effect of advantageously preserving a substantially constant alignment of the clip30in the clamp100, compared to a clamp of the prior art that does not possess any retaining means exerting on the threaded end31. More specifically, the longitudinal axis of the clip30and the longitudinal axis X of the main body10remain substantially identical, thus facilitating the insertion and the removal of the clamp100in the holes of the structures to be assembled.

It should be noted that the problem of misalignment of the clip relates mainly to the so-called “flat” clips, as opposed to cylindrical clips, when they are introduced into circular fastening holes. The clip30, according to the embodiment illustrated, is of “flat” type andFIGS.1and2make it possible to view its shape in two orthogonal planes.

Therefore, the alignment effect obtained by the spring is more noteworthy in the case of “flat” clips.

The fact that the compression spring60holds the threaded end31pressed against the threads of the tapped bore51also guarantees a grip facilitated between the threads during the screwing.

The clamp100such as described, with reference toFIG.3, makes it possible to provisionally assemble the two parts200aand200b, which may moreover be of different thicknesses, in view of their final fastening by riveting for example. The clamp100may also be used in the case of a plurality of parts to be assembled. For this, with reference toFIGS.1and8A, the clip30is initially introduced into the drilled holes of said parts, which are then positioned opposite one another, the clamp being in minimum tightening position with the clip in closed position. Still in minimum tightening position, the clamp100is introduced into the parts via its clip30until the bearing surface111of the collar11of the main body10comes into contact with a front face201aof the first part200a.

Subsequently, with reference toFIG.8B, the clamp100is progressively tightened by the rotation of the driver nut50, rotationally moveable in relation to the main body10, in order to bring back the hooking spur33of the clip30applied against a rear face202bof the second part200b. Indeed, as explained above, the rotation of the driver nut50produces a translation of the clip30along the longitudinal direction X, due to the cooperation between the tapped bore51and the threaded end31initially engaged in said bore. The movement of the clip30thus corresponds to its partial removal inside the driver nut50. The tightening of the clamp100is then continued until a maximum tightening position is obtained that corresponds to a firm compression of the parts200aand200bbetween the main body10and the hooking spur33. In this position, the hooking spur33is in contact with the rear face202bof the second part200bby its hooking surface331.

The hooking of the rear face202b, or more specifically of the wall of the drilled hole of said face, of the second part200bby the hooking spur33of the clip30is made possible by the opening of said clip as the clamp is tightened, this opening resulting by a moving apart of the branches32so that the width of the spur33at its hooking surface331is greater than the diameter of the drilled hole of the second part200bwherein the clamp is introduced.

Indeed, the movement of the clip30and, thereby of its branches32, in the direction going from the main body10to the driver nut50causes the branches32to move apart on the spreader40, the latter remaining fixed in relation to the main body10. The profile of the branches32, and in particular the inner profile in contact with the spreader40, has a shape adapted so that said branches start to move apart from one another from the start of the tightening of the clamp100. In the example illustrated inFIG.3, in closed position of the clip30, the portion of the slot34upstream of the spur33not occupied by the spreader40has a thickness decreasing from the end of said spreader, so that the penetration of the spreader into this portion of lower thickness causes the branches32to move apart.

The moving apart of the branches32of the clip30may continue until the spreader40passes through the hooking spur33as shown inFIG.8B.

Thus, the force exerted by the hooking spur, then in contact with the wall of the hole of the rear part of the assembly, drives it against the other parts, whereof the outer front part is abutting against the bearing surface of the main body. The parts are consequently firmly pressed.

FIGS.9A to9Cillustrate the clamp100in successive tightening positions, wherein the travel x of the clip30progressively decreases during the tightening to reach the minimum travel xmincorresponding to the total lowest thickness of an assembly for which the clamp100may be used.

Preferably, the clamp100has a larger diameter D, for example at its main body10, equal to 10.5 millimeters to the nearest metric tolerances. This limited size makes it possible to mount a plurality of clamps close together in the same assembly and also to facilitate the access by means such as robotized installation modules.

In view of the present description, some elements of the invention may be produced differently or replaced by other equivalent elements without departing from the scope of the invention, this not being limited solely to the example described and illustrated. For example, the washer72may be fastened to the threaded end31, or the threaded end31may be provided with a collar whereon the spring60rests in order to push back the clip30towards the driver nut and hold it coaxial with the main body10.