FR3142547A1 - METHOD AND DEVICE FOR CONTROLLING THE TIGHTENING TENSION OF AN AERONAUTICAL FASTENER - Google Patents

Abstract

METHOD AND DEVICE FOR CONTROLLING THE TIGHTENING TENSION OF AN AERONAUTICAL FASTENER The invention relates to a method of tightening a fastener (30), comprising the following steps: - provision of a screw (32) comprising a head (322), a threaded portion (324) and a recess (326); - insertion of the screw into a hole (20) and installation of a nut (34) on the threaded portion; - engagement of a tip (76) in the cavity, up to contact with the bottom; - rotation of the nut by blocking the rotation of the end piece and the screw; - excitation of an ultrasonic transducer (88) placed on the tip; - receiving and processing ultrasonic waves reflected from a front surface of the screw head, to calculate a tension in the screw; - stopping the rotation of the nut when said tension equals a predefined threshold. Figure for abstract: Figure 3

Description

METHOD AND DEVICE FOR CONTROLLING THE TIGHTENING TENSION OF AN AERONAUTICAL FASTENER Technical field of the invention

The present invention relates to a method for controlling the tightening tension of a fastener as well as a device enabling this control, in particular for the aeronautical industry.

Technical background

It is known in the art that in order to fix two elements together, for example structural elements of an aircraft, these elements comprise aligned holes intended for the mounting of fasteners which ensure the fixing of the elements by tightening them axially against each other.

In this application, the term “fastener” means an assembly comprising a screw and a nut. In the aeronautical industry, the tightening of the nut on the screw must be carried out at a torque predetermined by calculation during the development of the fastener to ensure the tightening of the elements and avoid their accidental separation during operation.

Suitable fasteners for such use are for example HI-LOK™ fasteners as described in US3138987A or HI-LITE™ screws as described in US4326825A. An example of a HI-LITE™ fastener is shown in Figures 1A and 1B.

The HI-LITE™ fastener includes a screw 10, having a protruding head 12, a smooth shank 14, and a threaded end 16. The threaded end 16 includes a hexagonal recess 18. The screw 10 is installed in a bore 20 made in first 22 and second 24 members until the head 12 bears on a front face 26 of the first member 22. The nut 30 is screwed onto the threaded end 16 emerging from the rear face 28 of the second member, opposite the face 28, the screw being immobilized by a wrench or bit (not shown) inserted into the hexagonal recess 18, until the nut contacts the face 28. The nut includes a break groove 32 designed to break at a predetermined tightening torque, providing a tension, or preload, in the screw 10 necessary to withstand the stresses of shear and traction exerted by elements 22, 24 on screw 10.

This assembly solution is widely used and is very efficient, but it does not allow you to check, once the nut is installed on the screw, that the installed tension does not vary over time.

When a conventional nut, without a shear groove, is used, tightening is generally carried out using a torque wrench to the predetermined torque. Even if the torque is well controlled using a wrench, the tolerances of geometry, surface condition and lubrication inevitably lead to a large dispersion of the preload actually installed, which can lead to a risk of breakage of the head or threads, or on the contrary, tightening to a preload lower than the desired preload.

Direct measurement of tension, i.e. the tensile force applied to the screw and the compression force applied to the elements held, is not possible. There are fasteners comprising one or more strain gauges, or an ultrasonic transducer, allowing indirect measurement of the tension of the screw during or after tightening the nut. The gauges or transducers must be positioned on the fastener and electrically powered. This solution therefore requires instrumenting each fastener, which significantly increases its price. Furthermore, the addition of components increases the weight of the fastener, which limits their use in large quantities on an aircraft since several tens of thousands of fasteners are installed on an aircraft. Furthermore, the resistance of electronic components to temperature variations, environmental conditions, and paint does not allow all fasteners to be instrumented and represents a difficulty in qualification. The addition of electrical contacts on the terminals of the gauges or transducers cannot be carried out on all fasteners either, since these terminals must be accessible.

Current technology therefore does not allow a fixing to be installed at a predetermined voltage in an industrial operating context, and this voltage to be checked repeatedly and reliably.

The present invention aims to remedy these drawbacks and relates to a control method and a centering device allowing its implementation, which are simple and effective.

The invention thus proposes a method for tightening at least one fastener, comprising the following steps: providing a screw comprising: a head having a flat front surface; a threaded portion; and a recess, comprising a flat bottom and a non-circular section; inserting the screw into a bore passing through at least two elements until one end of the threaded portion emerges from the elements, and placing a nut on the emerging end of the threaded portion of the screw; engaging an immobilizing tip in the recess, until a front face of the tip contacts the flat bottom of said recess, said immobilizing tip comprising a shape complementary to the non-circular section of said recess; rotating the nut on the threaded portion of the screw while blocking the rotation of the immobilizing tip and the screw; exciting an ultrasonic transducer disposed on a rear face of the tip, the ultrasonic transducer being capable of generating ultrasonic waves in the tip and the screw when the tip is engaged in the screw recess; receiving the ultrasonic waves reflected by the flat front surface of the screw head and processing the received ultrasonic waves to calculate a voltage in the screw; stopping rotation of the nut when the calculated voltage in the screw equals a predefined threshold voltage.

Thus, thanks to the invention, we ensure that the fixing is installed at the required tension, without the fixing having any transducer or sensor.

The method according to the invention may comprise one or more of the following characteristics, taken in isolation from one another or in combination with one another:

- the ultrasonic transducer is a piezoelectric transducer;

- at the stage of engaging the tip in the screw recess, the immobilizing tip is engaged with a predetermined pressure on the screw by means of at least one elastic member;

- a dry couplant is inserted between the front face of the tip and the flat bottom of the imprint prior to excitation of the transducer;

- a liquid or gel couplant is poured into the imprint prior to excitation of the transducer.

The present invention also relates to a tightening device allowing the implementation of a tightening method as described above, of a screw in a bore passing through at least two elements, the tightening device comprising: a body; an immobilizing tip fixed in rotation and axially movable relative to the body, the tip comprising: an anti-rotation interface configured to engage with a non-circular section of a recess of the screw; a flat front face, configured to contact a flat bottom of the recess; and an opposite rear face; a sleeve movable in rotation relative to the body and configured to drive a nut in rotation; and an ultrasonic transducer, arranged on the rear face of the tip, the ultrasonic transducer being capable of generating ultrasonic waves in the tip and in the screw when the front face of the tip is in contact with the flat bottom of the recess of the screw.

The device used allows fasteners to be installed at the desired tension in a uniform manner, which ensures increased reliability and repeatability of the tightening tension in the assembly.

The clamping device according to the invention may comprise one or more of the following features, taken in isolation from one another or in combination with one another:

- the clamping device further comprises an immobilizer support, said support comprising: a part fixed relative to the body; and a movable part, capable of sliding axially inside the fixed part; the ultrasonic transducer and the immobilizer tip being integral with said movable part;

- the clamping device further comprises a compression spring arranged in the immobilizing support, the spring bearing on the one hand on the movable part and on the other hand on the fixed part of the immobilizing support,

- the socket comprises a front housing, configured to receive the nut for rotating said nut;

- the tip has a density identical to or close to the density of the screw;

- the tip and screw are made of identical or similar materials.

Brief description of the figures

Other features and advantages of the invention will become apparent upon reading the detailed description which follows, for the understanding of which reference will be made to the appended drawings in which:

there is a side view of a prior art fastener;

there is a side and sectional view of a prior art fastener installed in a structure;

there is a side view of a fastener suitable for use in a tightening method according to one embodiment of the invention;

there is a schematic sectional view of a clamping device according to one embodiment of the invention and of the fixing of the , in a first step of a tightening method according to an embodiment of the invention;

there is a similar view the in a second step of said tightening process;

there is a view similar to Figures 3 and 4 in a third step of said tightening method; and

there is a block diagram illustrating steps of an embodiment of the method of tightening the fastener of the by means of the clamping device of figures 3, 4 and 5.

Detailed description of the invention

In the following description, the method and device for tightening a fastener are used to assemble aircraft structures.

This example is however not limiting, the method and the clamping device being applicable to other types of assembly or application, such as for example fasteners assembling structures of land vehicles or wind turbine blades.

Reference is now made to Figures 3 to 5 which show a clamping device 40 configured to clamp a fastener, according to one embodiment of the invention.

Said fixing, shown alone in , comprises a screw 32 and a nut 34. The screw 32 extends along an axis A and comprises a protruding head 322, a threaded portion 324 and an imprint 326.

The imprint 326 is arranged along the axis A and opens onto one end of the threaded portion 324, opposite the head 322. Transversely to the axis A, the imprint 326 has a non-circular section.

In the embodiment shown, the non-circular section is hexagonal in shape. Alternatively, the non-circular section of the imprint is multi-lobed, for example as described in the applicant's patent FR2967735B1, or of any other non-circular shape making it possible to block the rotation of the screw 32 by inserting a key or a bit of complementary shape.

Unlike the screw 10 of the prior art, the bottom 328 of the imprint is flat and parallel to the end surface 330 of the head 322. More precisely, the bottom 328 of the imprint and the end surface 330 of the head are perpendicular to the axis A.

Preferably, the flat bottom 328 is obtained either by machining the bottom of the imprint, previously produced by broaching, or by electroerosion, or by adding material to the conical bottom imprint so as to obtain a flat bottom. Preferably, the addition of material has a density comparable to that of the screw so as not to disperse or diffract or disturb the path of the ultrasonic waves, as will be described later. Preferably, the roughness Ra of the flat bottom 328 is less than 2.

Apart from the modification relating to the bottom of the imprint and the possible addition of a coupling agent, the screw 32 is similar to the screw 10 of the prior art previously described. In particular, the screw 32 is devoid of any tension sensor, bending sensor, transducer capable of emitting sound waves, ultrasonic waves, or any electrical or electronic component such as batteries, capacitors or antennas.

The nut 34 comprises external drive surfaces 36, for example six or twelve flat surfaces. A suitable nut is for example described in the applicant's patent EP2350473. The nut 34 is also devoid of any tension sensor, bending sensor, transducer capable of emitting sound or ultrasonic waves, or any electrical or electronic component such as batteries, capacitors or antennas.

The clamping device 40 extends along an axis X and comprises a tubular body 42, a sleeve 44 and an immobilizer support 46. The sleeve 44 is rotatable relative to the body 42. In the embodiment shown, the clamping device further comprises a hollow transmission shaft 48, secured to an axial end of the sleeve. The shaft 48 is configured to drive the sleeve 44 in rotation about the axis X.

In the embodiment shown, the clamping device further comprises ball bearings 50 and roller bearings 52. The ball bearings 50 are arranged radially between the sleeve 44 and the body 42, allowing rotation of the sleeve relative to the body. The roller bearings 52 will be described below.

The sleeve 44 is internally hollowed out, the hollowed out portion forming an internal housing extending axially between a first end 54 and an opposite second end 56, both ends being open.

The housing of the sleeve 44 comprises: a distal portion 60 close to the first end 54, an intermediate portion 64 and a proximal portion 66 close to the second end 56 ( ). The distal portion 60 has an inner diameter substantially smaller than the inner diameters of the intermediate 64 and proximal 66 portions. The intermediate portion 64 has a diameter substantially smaller than the inner diameter of the proximal portion 66.

The junction of the distal 60 and intermediate 64 portions forms a first shoulder 68. The junction of the intermediate 64 and proximal 66 portions forms a second shoulder 70 ( ).

The distal portion 60 of the sleeve 44 is configured to receive the nut 34 and drive it in rotation. The internal peripheral wall of the distal portion 60 comprises at least two flat faces 62 intended to engage with at least two flat drive surfaces 36 of the nut 34. Preferably, the sleeve is adapted to the shape of the nut that it must drive, and comprises for example as many flat faces as drive surfaces 36 of the nut. An axial dimension X ₁ of the distal portion 60 is configured to fully accommodate the nut 34 and a projecting part of the threaded portion 324 of the screw, when the nut is installed on the threaded portion and in contact with the rear surface 28 of the second element 24, as shown in .

The immobilizer support 46 comprises a fixed part 72 and a movable part 74. The fixed part 72 is fixed relative to the body 42 in rotation and in translation. The movable part is able to slide axially in the fixed part.

The fixed part 72 comprises a tubular portion 722 and a crown 724, adjacent along the X axis. The tubular portion 722 is arranged in the hollow shaft 48. The roller bearings 52 are arranged radially between the tubular portion 722 and the shaft 48, allowing the rotation of said shaft relative to the fixed part 72 of the immobilizer support 46.

The crown 724 has a tubular shape. A first portion of the crown 724 extends into the hollow shaft and a second portion of said crown extends into the proximal portion 66 of the sleeve 44. An external diameter of the crown 724 is less than an internal diameter of the proximal portion 66 of the sleeve 44. A free end of the crown is arranged near the second shoulder 70. The junction between the tubular portion 722 and the crown 724 forms a counterbore 726, such that the internal diameter of the crown is greater than the internal diameter of the tubular portion 722.

The fixed part 72 also comprises an annular surface 728 perpendicular to the axis X, abutting against the needle rollers 52. The fixed part is thus axially blocked in the hollow shaft and the sleeve 44, between the second shoulder 70 of the sleeve 44 and the needle rollers 52, with a small axial clearance.

The movable portion 74 comprises a collar 742 and a skirt 744 extending axially from the collar. The external diameter of the collar 742 is greater than the external diameter of the skirt 744.

The collar 742 is housed in the second part of the crown 724, itself housed in the proximal portion 66 of the sleeve 44. The external diameter of the collar 742 is less than the internal diameter of the crown 724, with sufficient clearance for the movable part 74 to be able to move axially in the crown 724 of the fixed part 72.

The skirt 744 is able to slide in the intermediate portion 64 of the sleeve, the external diameter of the skirt 744 being less than the internal diameter of the intermediate portion 64.

The clamping device 40 further comprises an immobilizer tip 76 and an ultrasonic transducer 88, housed within the immobilizer support 46. In the embodiment shown, the clamping device 40 also comprises: a resilient member such as a compression spring 90; and a cable 92.

The tip 76 comprises a front face 78 and a rear face 80, both being flat and perpendicular to the X axis. The immobilizing tip 76 comprises an anti-rotation interface 82, adapted to engage in the imprint 326 of the screw 32, the free end of which is the front face 78. The interface 82 may be a cylinder with a hexagonal base if the imprint 326 is hexagonal, or a cylinder with a multi-lobed base if the imprint is multi-lobed. Such a tip is for example described in the applicant's patent FR2967735.

Preferably, the material of the tip 76 is identical or similar to the material of the screw 32. Alternatively, the acoustic impedance - or density - of the tip is identical or close to the acoustic impedance - respectively density - of the screw.

Acoustic impedance is the product of the wave speed in the material and the density of the material. Too great a difference in acoustic impedance can cause a reflection of part of the waves at the interface of the tip and the screw, thus a loss of signal.

For example, if the screw is made of TA6V titanium alloy, the tip will preferably be made of TA6V titanium alloy, or a similar alpha-beta titanium alloy.

In the embodiment shown, the interface 82 is connected by a conical portion to a cylindrical portion of enlarged diameter, in which an annular groove 84 is made. This groove is shown with a V-shaped section in the figures, but it can adopt all sorts of shapes.

The immobilizing tip 76 is fixed to the movable part 74 of the immobilizing support by a pin 86, inserted into a hole in the movable part 74 and housed in the annular groove 84.

The ultrasonic transducer 88 is an ultrasonic transceiver, attached to the rear face 80 of the tip 76. The transducer is connected by the cable 92 to a power supply (not shown) and functions as a transmitter, converting electrical energy into mechanical oscillations to produce ultrasound transmitted into the screw 32 via the immobilizing tip 76. The transducer 88 also functions as a receiver, converting a reflected ultrasonic wave into an electrical signal, transmitted via the cable 92 to an analog or digital electronic device such as a processor (not shown), capable of processing the received electrical signal to calculate the tension in the screw. The transducer may comprise a piezoelectric crystal. The electronic device may be integrated into the tool, or may be remote.

The assembly formed by the transducer 88 and the immobilizing tip 76 is thus secured to the mobile part 74 of the immobilizing support, via the pin 86.

Preferably, a dry couplant is interposed between the front face 78 of the tip and the bottom 328 of the screw recess, in order to improve the acoustic transmission. The couplant may be, for example, a sheet of tin, silver, copper or an elastomeric coupling material such as Aqualene, developed by the company Innovation Polymers, Canada. The sheet has a thickness preferably between 0.0175 mm and 0.6 mm. The sheet may be deposited dry or wet, or even glued, on the front face of the tip.

The compression spring 90 is arranged in the crown 724 of the fixed part 72 of the support 46. It bears axially on the one hand on the collar 742 of the movable part 74 of the support 46, and on the other hand on the counterbore 726 of the fixed part 72 of the support. The collar ensures guidance of the assembly formed by the transducer 88 and the immobilizing end piece 76 parallel to the axis of revolution X of the clamping device 40. The guidance thus ensures that the ultrasonic waves are emitted in the axis X of the clamping device.

The assembly formed by the immobilizing tip 76 and the transducer 88 is thus movable in the axial direction X between a first position, in which the spring is relaxed (figures 3 and 4), and a second position, in which the spring is compressed ( ) and capable of imparting a predetermined pressure to the immobilizing tip 76. The assembly formed by the immobilizing tip 76 and the transducer 88 is fixed in rotation relative to the body 42.

A method of tightening the fastener 32, 34 in two elements 22, 24 by means of the device 40 will now be described. This method makes it possible to tighten the fastener while controlling the tightening tension induced in the screw by tightening the nut on the screw and the two elements.

We now refer to the showing the steps of the method 100 for tightening a fastener, implemented by means of a tightening device 40 described previously.

During a step 101, the screw 32 is inserted into the bore 20 of the elements 22, 24 previously described, until one end of the threaded portion 324 emerges from the element 24. The nut 34 is put in place on said end of the threaded portion 324, engaging a few threads, as visible in the .

Then, during a step 102, the tightening device 40 is approached to the fastener so that the immobilizing tip 76 engages in the imprint 326 of the screw 32. The movement of the device 40 is continued until the front face 78 of the tip contacts the flat bottom 328 of the imprint, and the distal portion 60 of the socket contacts the drive surfaces 36 of the nut, as visible in the . In this position, the axis X of the clamping device coincides with the axis A of the fastener; and the front 78 and rear 80 flat faces of the end piece 76, the flat bottom 328 of the imprint and the face 330 of the head end of the screw are parallel to each other and perpendicular to the coincident axes of revolution X and A. The collar 742 is moved axially, away from the shoulder 70, due to the engagement between the screw and the immobilizer.

The front face 78 of the tip is held in contact against the flat bottom 328 of the imprint with a pressure predetermined by the stiffness of the spring 90.

Due to the engagement of the anti-rotation surfaces of the tip and the screw, the assembly formed by the ultrasonic transducer 88, the immobilizing tip 76 and the screw 32 is fixed in rotation.

Then, during a step 103, the sleeve 44 is rotated along the X axis relative to the body 42. The screw being blocked in rotation relative to the body by means of the immobilizing end piece 76, the nut 34 is screwed onto the threaded portion 324 of the screw.

During a step 104, simultaneous with step 103, US ultrasounds are emitted by the transducer 88 through the immobilizing tip 76 and the screw 32 ( ). The immobilizing tip 76 thus ensures the propagation of the waves transmitted by the transducer towards the fixing via the bottom 328 of the flat imprint.

The US ultrasound propagates in the screw, reflects on the end surface 330 of the screw head and returns to the transducer 88 in the form of an echo. The transducer 88 transforms the received acoustic energy into electrical energy, and transmits this energy in the form of an electrical signal to a remote electronic device via the cable 92.

During a step 105, the external electronic device processes the received electrical signal in order to determine a voltage in the screw.

According to one embodiment, the tension in the screw 32 is determined from the strain of the screw and the Young's modulus via Hooke's law. The strain of the screw is obtained from measurements of the time of a round trip of a wave, and compared to a pre-recorded strain value corresponding to a predefined threshold tension. The Young's modulus E is a constant associated with the material of the screw 32.

Alternatively, the voltage in the screw 32 is determined from the measurement of the variation of the impedance of the screw, via the measurement of the resonance frequency which depends on the stress in the screw.

Alternatively, other methods of calculating bolt tension can be used, such as one of the methods described in the publication “Review of Bolted Connection Monitoring” by Tao Wand et al., available at the URL http://dx.doi.org/10.1155/2013/871213.

Then, during a step 106, the electronic device emits a signal, or displays an indication that the induced voltage is equal to the predefined threshold voltage, so that an operator installing the fastener stops tightening the nut. Alternatively, the electronic device is configured to control the tightening process and stop it as soon as the value of the calculated voltage equals the predefined threshold voltage, without human intervention.

The predefined threshold voltage may be the voltage predetermined by calculation when designing the fastener, or a voltage slightly lower than this value in order to take into account the calculation time of the electronic device and the time required to display the stop instruction, during which times the nut is rotated by the tightening device.

Then, the clamping device 40 is disengaged from the screw 32 and the nut 34, and can be used to install another fastener.

Optional steps can be added to the steps previously described in order to improve the control of the clamping tension. These steps are shown in broken lines on the .

Thus, during an optional step 107, inserted between steps 101 and 102, a dry couplant can be intercalated between the front face of the tip and the flat bottom 328 of the imprint of the screw 32 so as to cover the flat bottom 328 of the imprint. This couplant can be useful for ensuring better transmission of the waves in the screw 32.

Alternatively, this couplant may be a liquid couplant, such as water, or a gel couplant, poured into the impression.

In an optional step 108, after step 106, the calculated tension value and the reference of the fastener may be recorded in an external database. This recording may be necessary to verify the tension installed in the fastener over time.

The tightening method described above has the advantage of installing a recessed fastener without additional delay compared to a prior art fastener, while reliably and repeatably controlling the tension in the screw.

The device implemented also allows for a gain in productivity. Indeed, the device according to the invention allows for increased precision during control and/or measurements, and therefore eliminates additional verification steps in the event of doubt about the reliability of a measurement.

The tension in the screw can be measured over time using the previously described tightening device by disengaging the socket 44, since the installed tension of the measured fastener has been recorded in a database, during the additional step 108.

Claims (11)

Method for controlled tightening of a fastener (30) comprising a screw and a nut, characterized in that the method comprises the following steps:
a. Providing a screw (32) comprising: a head (322) having a flat front surface (330); a threaded portion (324); and a recess (326), comprising a flat bottom (328) and a non-circular section;
b. Inserting (101) the screw into a bore (20) passing through at least two elements (22, 24) until one end of the threaded portion emerges from the elements, and placing a nut (34) on the emerging end of the threaded portion of the screw;
c. Engagement (102) of an immobilizing tip (76) in the imprint, until a front face (78) of the tip contacts the flat bottom (328) of said imprint, said immobilizing tip comprising a shape complementary to the non-circular section of said imprint;
d. Rotating (103) the nut on the threaded portion of the screw while blocking the immobilizing tip and the screw in rotation;
e. Excitation (104) of an ultrasonic transducer (88) disposed on a rear face (80) of the tip, the ultrasonic transducer being capable of generating ultrasonic waves in the tip (76) and the screw (32) when the tip is engaged in the imprint of the screw;
f. Receiving (105) ultrasonic waves reflected from the flat front surface of the screw head and processing the received ultrasonic waves to calculate a tension in the screw;
g. Stop (106) the rotation of the nut when the calculated tension in the screw equals a predefined threshold tension. The tightening method of claim 1 wherein the ultrasonic transducer (88) is a piezoelectric transducer. Tightening method according to claim 1 or 2 wherein, in the step of engaging the tip in the imprint of the screw, the immobilizing tip (76) is engaged with a predetermined pressure on the screw (32) by means of at least one elastic member (90). Method according to one of the preceding claims, in which a dry couplant is interposed between the front face (78) of the tip and the flat bottom (328) of the imprint prior to the excitation of the transducer (88). Method according to one of the preceding claims, in which a liquid or gel couplant is poured into the imprint (326) prior to the excitation of the transducer (88). Clamping device configured for implementing a controlled clamping method according to one of claims 1 to 5, of a screw in a bore (20) passing through at least two elements (22, 24), the clamping device comprising:
- a body (42);
- a tip (76) immobilizing fixed in rotation and axially movable relative to the body (42), the tip comprising: an anti-rotation interface (82) configured to engage with a non-circular section of a recess of the screw; a flat front face (78), configured to contact a flat bottom (328) of the recess; and an opposite rear face (80);
- a socket (44) movable in rotation relative to the body (42) and configured to drive a nut (34) in rotation; and
- an ultrasonic transducer (88), arranged on the rear face (80) of the tip, the ultrasonic transducer (88) being capable of generating ultrasonic waves in the tip (76) and in the screw (32) when the front face (78) of the tip is in contact with the flat bottom (328) of the imprint (326) of the screw. Clamping device according to claim 6, further comprising an immobilizer support (46), said support comprising: a fixed part (72) relative to the body; and a movable part (74), capable of sliding axially inside the fixed part; the ultrasonic transducer (88) and the immobilizer tip (76) being integral with said movable part (74). Clamping device according to claim 7, comprising a compression spring (90) arranged in the immobilizing support (46), the spring bearing on the one hand on the movable part (74) and on the other hand on the fixed part (72) of the immobilizing support. Clamping device according to one of claims 6 to 8, in which the socket comprises a front housing (60), configured to receive the nut (34) for driving said nut in rotation. Clamping device according to one of claims 6 to 8, in which the tip has a density identical to or close to a density of the screw. Clamping device according to one of claims 6 to 8, in which the tip and the screw are made of identical or similar materials.