EP3067157B1

EP3067157B1 - A system for coupling/decoupling a threaded tie-rod to/from a tie-rod seating in a gun for deforming fixing elements, and a gun with the system

Info

Publication number: EP3067157B1
Application number: EP16155560.2A
Authority: EP
Inventors: Nerio Bentivogli; Fabio EVANGELISTI
Original assignee: OBER SpA
Current assignee: OBER SpA
Priority date: 2015-03-11
Filing date: 2016-02-12
Publication date: 2018-04-04
Anticipated expiration: 2036-02-12
Also published as: HUE039574T2; TR201809469T4; PT3067157T; ES2676051T3; SI3067157T1; PL3067157T3; HRP20181001T1; ITUB20150545A1; EP3067157A1; RS57427B1

Description

The present invention relates to the technical sector of riveting guns, with particular reference to riveting guns having electro-hydraulic or pneumo-hydraulic activation. A system for coupling/decoupling a threaded tie-rod to/from a tie-rod seating in a gun for deforming fixing elements is disclosed in EP 1.336.442 A2 , on which the preamble of claim 1 is based. Document EP 2.093.024 discloses an electro-hydraulic gun for deforming rivets, comprising:

an activating trigger;
supply means for providing electrical energy;
a threaded tie-rod for engaging in a threaded axial hole of a rivet;
an oil-dynamic system comprising an oil-dynamic fluid, a cylinder, internally of which a piston slides, and activating means destined, by the action of the oil-dynamic fluid, to axially translate the threaded tie-rod in such a way as to determine a plastic deformation of a predetermined portion of the rivet so as to block it to a corresponding wall;
a first electrical micromotor for commanding the compression and discharge runs of the piston internally of the cylinder, respectively destined to raise the pressure of the oil-dynamic fluid up to a maximum predetermined value, and to reduce the pressure of the oil-dynamic fluid;
a second micromotor able to set the threaded tie-rod in rotation to right or left so as to engage or disengage the threaded tie-rod to or from the threaded axial hole of the rivet;
an electronic control unit able to command the first electrical micromotor and the second electrical micromotor.

The supply means are able to supply electrical energy to the electronic control unit, to the first micromotor and to the second micromotor. Document EP 0.999.906 discloses an electro-hydraulic gun for deforming rivets, comprising:

- - an activating trigger;
- - a source of compressed air;
- a threaded tie-rod for engaging in a threaded axial hole of a rivet;
- an oil-dynamic system comprising an oil-dynamic fluid, a cylinder, internally of which a piston slides, and activating means destined, by the action of the oil-dynamic fluid, to axially translate the threaded tie-rod in such a way as to determine a plastic deformation of a predetermined portion of the rivet so as to block it to a corresponding wall;
- a pneumatic motor able to set the threaded tie-rod in rotation to right or left so as to engage or disengage the threaded tie-rod to or from the threaded axial hole of the rivet;
- a pneumatic system, supplied by the source of compressed air, comprising valve means for commanding supply to the motor and for commanding the compression and discharge runs of the piston internally of the cylinder, respectively destined to raise the pressure of the oil-dynamic fluid up to a maximum predetermined value, and to reduce the pressure of the oil-dynamic fluid.

Independently of the activating mode, whether electro-hydraulic or pneumo-hydraulic, the guns for deforming rivets include, in known ways, a containing structure of the constituting elements which comprises a grip connected to an upper body comprising in turn a rear shell, fixed to the grip, and a front shell coupled by threading to the rear shell.
A terminal sleeve is coupled by threading to the free end of the shell, which in the assembled configuration of the gun is freely engaged by the projecting end of the threaded tie-rod.
Starting from a work configuration with use of a predetermined threaded tie-rod suitable for operating on a first type of rivet, when for reasons of work necessity the dimensions of the rivets being worked change it is consequently necessary to replace the threaded tie-rod with another tie-rod suitable for operating on the new type of rivet.
To remove the old tie-rod first the terminal sleeve is disengaged from the front shell, using a suitable tool, and then the front shell is disengaged from the rear shell, using a suitable tool.
In this way the tie-rod seating becomes accessible as well as the corresponding old tie rod, enabling removal of the old tie-rod from the tie-rod seating.
Thereafter the new tie-rod is preliminarily positioned in the tie-rod seating and the front shell is coupled to the rear shell, using a suitable tool, and the terminal sleeve is coupled to the front shell, again using a suitable tool. The tie-rod seating is normally compatible with a broad range of tie-rod types, so as to enable a wide-ranging "setting" during the working stage.
The steps of removing the old tie-rod and positioning the new tie-rod are often long and laborious, especially due to the coupling/decoupling of the tie rod with the tie-rod seating therefor, which can also require the use of appropriate supplementary tools.
These steps mean that the gun is inactive and this has a significantly negative effect on the work cycle.
In some applications the coupling/decoupling operation has been simplified by adopting a tie-rod seating known as "open", with a bayonet coupling of the tie-rod.
In these cases the tie-rod is inserted/de-inserted laterally from the tie-rod seating without the aid of special supplementary tools.
A drawback of these applications consists in the necessary over-dimensioning of the tie-rod in order to withstand the mechanical stresses, with a consequent increase in the overall weight and the volume of the riveting zone.
An aim of the invention is to obviate the above-described drawbacks, by providing a system for coupling/decoupling a threaded tie-rod to/from a tie-rod seating in a gun for deforming fixing elements, able to accelerate the steps of replacing the threaded tie-rod which operates on the same fixing elements.
A further aim of the invention is to disclose a novel system for coupling/decoupling a threaded tie-rod to/from a tie-rod seating, able to accelerate the steps of replacing the threaded tie-rod without requiring any use of special supplementary tools, while at the same time limiting the weights and volumes of the riveting zone.
A further aim of the invention is to provide a gun for deforming fixing elements that is able to limit the inactive periods, to the advantages of the productivity of the work cycle.
These aims are attained by a system for coupling/decoupling a threaded tie-rod to/from a tie-rod seating in a gun for deforming fixing elements, realised according to claim 1.
In particular and further embodiments, the disclosed system for coupling/decoupling a threaded tie-rod to/from a tie-rod seating in a gun for deforming fixing elements comprises one or more of the following characteristics, considered singly or in combination:

means are included for guiding in translation and/or inclination of the threaded tie-rod with respect to the axis of the sleeve during the step of engaging/disengaging the threaded tie-rod to/from the sleeve;
the guide means comprise an insert drawn by the shaft of the activating motor and positioned in proximity of the rear head of the sleeve and orientated according to a diametric plane of the sleeve, and a groove fashioned at the rear end of the threaded tie-rod, which extends with respect to a diametric plane of the threaded tie-rod;
the insert, during the step of engaging/disengaging of the rear end of the threaded tie-rod to/from the sleeve, being able to insert internally of the groove;
the insert is drawn by the shaft of the activating motor with interposing of elastic means which facilitate the coupling of the insert with the groove during the step of engaging/disengaging of the rear end (of the threaded tie-rod to/from the sleeve;
the elastic means enable stabilising the threaded tie-rod in the alignment configuration with the axis of the sleeve;
the groove fashioned at the rear end of the threaded tie-rod comprises: a first straight portion which extends inclined with respect to the axis of the threaded tie-rod, and a second straight portion, for connecting the first portion, which extends perpendicularly with respect to the axis of the threaded tie-rod;
during the engaging step of the rear end of the threaded tie-rod with the sleeve, the insert involves in succession the first portion of the groove and then the second portion; during the step of disengaging the rear end of the threaded tie-rod from the sleeve, the insert involves in succession the second straight portion of the groove and therefore the first straight portion.

The characteristics of the invention will be highlighted in the following in which some preferred but not exclusive embodiments will be described, with reference to the appended tables of drawings, in which:

figures 1, 1A schematically illustrate two lateral and plan views of a riveting gun in operating steps in which access is enabled to the threaded tie-rod and the tie-rod seating;
figures from 2A to 2D illustrate, in smaller scale, lateral views of successive steps of the proposed system during the step of decoupling the old tie-rod from the tie-rod seating;
figure 3 schematically illustrates a lateral view of the riveting pistol illustrated in figure 1 during operating steps of inserting a new tie-rod;
figures from 4A to 4D illustrate, in smaller scale, lateral and detailed views of successive steps of the proposed system during the step of coupling the new tie-rod to the tie-rod seating.

With reference to the above-described tables reference numeral 1 denotes an electro-hydraulic gun for deforming the fixing elements, in the following referred to a riveting gun for the sake of simplicity, provided with a system for coupling/decoupling a threaded tie-rod (2) to/from a tie-rod seating (3).
The riveting pistol (1) comprises, in known ways as indicated in the introductory preamble:

an activating trigger (8);
a threaded tie-rod (2) for engaging, with a front end (2A) thereof, in a threaded axial hole of a deformable fixing element;
a tie-rod seating (3) in which the rear end (2P) of the threaded tie-rod (2) can be positioned;
an oil-dynamic system comprising an oil-dynamic fluid, a cylinder, internally of which a piston slides, and activating means destined, by the action of the oil-dynamic fluid, to axially translate the tie-rod seating (3) and the threaded tie-rod (2) in such a way as to determine a plastic deformation of a predetermined portion of the fixing element so as to block the fixing element to a corresponding surface;
a first electric micromotor for commanding compression and discharge runs of the piston internally of the cylinder;
a second electric micromotor able to set the threaded tie-rod (2) and the tie-rod seating (30) in rotation so as to engage or disengage the front end (2A) of the threaded tie-rod (2) to or from the threaded axial hole of the fixing element;
at least an electronic control unit able to control and command the first and second electric micromotors;
supply means for providing electrical energy to the electronic control unit and the first and second electric micromotors;

In known ways, the riveting gun (1) comprises a containing structure of the constituting elements which comprises a grip (100) connected to an upper body comprising in turn a rear shell (101P), fixed to the grip (100), and a front shell (101A) coupled by a threading to the rear shell (101P).
A terminal sleeve (102) is coupled by a threading to the free end of the front shell (101A), which in the assembled configuration of the gun (1) is freely engaged by the front projecting end (2A) of the threaded tie-rod (2). In a novel way, the riveting gun (1) comprises a system for coupling/decoupling the threaded tie-rod (2) with/from the tie-rod seating (3) that is able to significantly accelerate the replacement steps of the threaded tie-rod (2) which operates on the fixing elements, advantageously limiting the inactive periods of the riveting gun (1), to the advantage of the productivity of the work cycle.
On the basis of this system, and in a novel way, the tie-rod seating (3) comprises a tubular sleeve (30) provided with a front head (30A) having a truncoconical geometry that enables transit of the front end (2A) of the threaded tie-rod (2), and a lateral slit (4) which extends longitudinally, enabling transit of the front end (2A) and the rear end (2P) of the threaded tie-rod (2), facilitating insertion of the rear end (2P) of the threaded tie-rod (2) internally of the sleeve (30) and the corresponding alignment of the threaded tie-rod (2) with the axis (Y) of the sleeve (30).
The front end (2A) of the threaded tie-rod (2) has a cylindrical geometry and the rear end (2P) of the threaded tie-rod (2) has a truncoconical geometry. The front head (30A) and the lateral slit (4) of the sleeve (30) are profiled such as to enable translation (T) and/or inclination (R) of the threaded tie-rod (2) with respect to the axis (Y) of the sleeve (30) during the step of engaging/disengaging of the threaded tie-rod (2) to/from the sleeve (30).
The disclosed system for coupling/decoupling a threaded tie-rod (2) to/from the tie-rod seating (3) comprises means for guiding in translation (T) and/or inclination (R) the threaded tie-rod (2) with respect to the axis (Y) of the sleeve (30) during the step of engaging/disengaging the threaded tie-rod (2) to/from the sleeve (30).
In a preferred embodiment, illustrated in the appended figures of the drawings, the guide means comprise:

an insert (5) drawn by the shaft (50) of the activating motor and positioned in proximity of the rear head (30P) of the sleeve (30) and orientated according to a diametric plane of the sleeve (30),
a groove (6) fashioned at the rear end (2P) of the threaded tie-rod (2), which extends with respect to a diametric plane of the threaded tie-rod (2).

The insert (5), during the step of engaging/disengaging of the rear end (2P) of the threaded insert (2) to/from the sleeve (30), is able to insert internally of the groove (6).
As can be seen in particular from figures 4A-4D, the insert (5) is drawn by the shaft (50) of the activating motor with interposing of elastic means (9) which facilitate the coupling of the insert (5) with the groove (6) during the step of engaging/disengaging of the rear end (2P) of the threaded tie-rod (2) to/from the sleeve (30).
At the end of the engaging step of the rear end (2P) of the threaded tie-rod (2) with the sleeve (30), the elastic means (9) enable stabilising the threaded tie-rod (2) in the alignment configuration with the axis (Y) of the sleeve (30).
By way of example the groove (6) realised at the rear end (2P) of the threaded tie-rod (2) comprises a first straight portion (61) which extends inclined with respect to the axis (X) of the threaded tie-rod (2), and a second straight portion (62), for connecting the first portion (61), which extends perpendicularly with respect to the axis (X) of the threaded tie-rod (2).
During the engaging step of the rear end (2P) of the threaded tie-rod (2) with the sleeve (30), the insert (5) involves in succession the first portion (61) of the groove (6) and then the second portion (62).
On the contrary, during the disengaging step of the rear end (2P) of the threaded tie-rod (2) from the sleeve (30), the insert (5) involves in succession the second portion (62) of the groove (6) and then the first portion (61).
With the threaded tie-rod (2) in the alignment configuration with the axis (Y) of the sleeve (30), stabilising configurations are possible, which cooperate with the guide means of the threaded tie-rod (2) and with the elastic means (9).
These configurations comprise a first truncoconical portion (71), fashioned at the front end (30A) of the sleeve (30), able to abut against a corresponding second truncoconical portion (72), fashioned in proximity of the rear end (2P) of the threaded tie-rod (2) in the alignment configuration of the threaded tie-rod (2) with the axis (Y) of the sleeve (30).
The abutment between the first (71) and second (72) truncoconical portions is realised on completion of the insertion step of the threaded tie-rod (2) internally of the sleeve (30), with the elastic means (9) pressing the insert (5) against the second straight portion (62) of the groove (6).
Starting from a work configuration characterised by use of a predetermined threaded tie-rod (2) suitable for operating on a first type of rivet, when for reasons of work necessity the dimensions of the rivets being worked change it is consequently necessary to replace the threaded tie-rod (2) with another tie-rod suitable for operating on the new type of rivet.
To remove the old tie-rod (2) first the terminal sleeve (102) is disengaged from the front shell (101A), using a suitable tool (109), and then the front shell (101A) is disengaged from the rear shell (101P), using a suitable second tool (110) (figures 1, 1A).
In this way the tie-rod seating (3) becomes accessible as well as the corresponding old tie rod (2), enabling removal thereof from the tie-rod seating (3).
Figures from 2A to 2D illustrate lateral views of successive steps of the decoupling of the old tie-rod (2) from the tie-rod seating (3).
On conclusion of the de-coupling, first the new tie-rod (2) is preliminarily positioned in the tie-rod seating (3) and the front shell (101A) is coupled to the rear shell (101P), using the second tool (110), and the terminal sleeve (102) is coupled to the front shell (101A), using the first tool (109) (figure 3).
Figures from 4A to 4D illustrate detailed lateral views of successive steps of the coupling of the new tie-rod (2) to the tie-rod seating (3).
Figure 4A illustrates the translating insertion (T) of the front end (2A) of the threaded tie-rod (2) in the lateral slit (4) of the sleeve (30), with a successive (not illustrated) inclination (R) for "aligning" the front end (2A) of the threaded tie-rod (2) with the front head (30A) of the sleeve (30).
Figure 4B illustrates how the stem of the threaded tie-rod (2), when advancing (T), involves both the lateral slit (4) and the front head (30A) of the sleeve (30), with a successive inclinations (R) for facilitating the inserting of the rear end (2P) of the threaded tie-rod (2) internally of the sleeve (30).
Figure 4B shows the first engagement of the insert (5) with the first portion (61) of the groove (6), which extends inclined with respect to the axis (X) of the threaded tie-rod (2), with an initial stressing of the elastic means (9).
In figure 4C the threaded tie-rod (2) is still advancing (T), so as to complete, with further inclinations (R), the inserting of the rear end (2P) of the threaded tie-rod (2) internally of the sleeve (30).
In figure 4C it can be observed how the insert (5), subjected to the action of the elastic means (9) and still engaged with the first portion (61) of the groove (6), is in proximity of the passage of the second portion (62) of the groove (6), which extends perpendicularly with respect to the axis (X) of the threaded tie-rod (2).
In figure 4D the threaded tie-rod (2) is aligned with the axis (Y) of the sleeve (30) and the rear end (2P) thereof is disengaged from the lateral slit (4) and positioned internally of the sleeve (30).
In figure 4D it can be observed how the insert (5) is pressed by the elastic organs (9) against the second portion (62) of the groove (6). The steps of the decoupling of the old tie-rod (2) from the tie-rod seating (3) are the same that can be deduced by observing figures from 4D to 4A, and obviously inverting the translation (T) and the inclination (R) directions.
It can easily be understood that the front head (30A) and the lateral slit (4) of the sleeve (30) are profiled such as to enable translation (T) and/or inclination (R) of the threaded tie-rod (2) with respect to the axis (Y) of the sleeve (30) during the step of engaging/disengaging of the threaded tie-rod (2) to/from the sleeve (30).
The foregoing description and the tables of drawings refer purely by way of example to a system for coupling/decoupling a threaded tie-rod to/from a tie-rod seating applied to a riveting gun having an electro-hydraulic activation.
It is however understood that the system for coupling/decoupling a threaded tie-rod to/from a tie-rod seating can equally be applied to a riveting gun having an pneumo-hydraulic activation comprising, in known ways indicated in the introductory preamble:

an activating trigger;
a source of compressed air;
a threaded tie-rod for engaging in a threaded axial hole of a rivet;
an oil-dynamic system comprising an oil-dynamic fluid, a cylinder, internally of which a piston slides, and activating means destined, by the action of the oil-dynamic fluid, to axially translate the threaded tie-rod in such a way as to determine a plastic deformation of a predetermined portion of the rivet so as to block it to a corresponding wall;
a pneumatic motor able to set the threaded tie-rod in rotation to right or left so as to engage or disengage the threaded tie-rod to or from the threaded axial hole of the rivet;
a pneumatic system, supplied by the source of compressed air, comprising valve means for commanding supply to the motor and for commanding the compression and discharge runs of the piston internally of the cylinder, respectively destined to raise the pressure of the oil-dynamic fluid up to a maximum predetermined value, and to reduce the pressure of the oil-dynamic fluid.

From the above-described it can easily be observed that the present system for coupling/decoupling a threaded tie-rod to/from a tie-rod seating in an electro-hydraulic or pneumo-hydraulic riveting gun evidently enables accelerating the steps of replacing the threaded tie-rod which operates on the rivets (deformable fixing elements).
This is due to the presence and the particular conformation of both the front head and the lateral slit of the sleeve, which enable simple and easy steps of extraction/insertion of the threaded tie-rod from/into the tie-rod seating, significantly accelerating the setting steps of the riveting gun.
This characteristic enables limiting the inactive stages of the riveting gun during the setting step, to the advantage of the productivity of the work cycle. The system for coupling/decoupling of the invention further enables accelerating the steps of replacing the threaded tie-rod without any use of special supplementary tools, while at the same time limiting the weights and volumes of the riveting zone.

Claims

A system for coupling/decoupling a threaded tie-rod to/from a tie-rod seating in a gun for deforming fixing elements,
the threaded tie-rod (2) comprising a front end (2A) for engaging in a threaded axial hole of the deformable fixing element, and a rear end (2P) provided for coupling with the tie-rod seating (3); the threaded tie-rod (2) being, by action of an oil-dynamic fluid, able to translate axially so as to determine a plastic deformation of a predetermined portion of the fixing element so as to block the fixing element to a corresponding wall, and by action of a motor is able to rotate with respect to the translation axis in order to enable the threaded tie-rod (2) to engage/disengage to and from the threaded axial hole of the deformable fixing element; the coupling system being characterised in that the tie-rod seating (3) comprises a tubular sleeve (30) provided with:
- a front head (30A), having a truncoconical geometry and enabling transit of the front end (2A) of the threaded tie-rod (2), and

- a lateral slit (4) which extends longitudinally, enabling transit of the front end (2A) and the rear end (2P) of the threaded tie-rod (2), facilitating insertion of the rear end (2P) of the threaded tie-rod (2) internally of the sleeve (30) and the alignment of the threaded tie-rod (2) with the axis (Y) of the sleeve (30);
with the front end (2A) of the threaded tie-rod (2) having a cylindrical geometry and the rear end (2P) of the threaded tie-rod (2) having a truncoconical geometry;
the front head (30A) and the lateral slit (4) of the sleeve (30) being profiled such as to enable translation (T) and/or inclination (R) of the threaded tie-rod (2) with respect to the axis (Y) of the sleeve (30) during the step of engaging/disengaging of the threaded tie-rod (2) to/from the sleeve (30).
The system of claim 1, characterised in that it comprises means for guiding in translation (T) and/or inclination (R) the threaded tie-rod (2) with respect to the axis (Y) of the sleeve (30) during the step of engaging/disengaging the threaded tie-rod (2) to/from the sleeve (30).
The system of claim 2, characterised in that the guide means comprise:
- an insert (5) drawn by the shaft (50) of the activating motor and positioned in proximity of a rear head (30P) of the sleeve (30) and orientated according to a diametric plane of the sleeve (30),

- a groove (6) fashioned at the rear end (2P) of the threaded tie-rod (2), which extends with respect to a diametric plane of the threaded tie-rod (2),
the insert (5), during the step of engaging/disengaging of the rear end (2P) of the threaded tie-rod (2) to/from the sleeve (30), being able to insert internally of the groove (6).
The system of claim 3, characterised in that the insert (5) is drawn by the shaft (50) of the activating motor with interposing of elastic means (9) which facilitate the coupling of the insert (5) with the groove (6) during the step of engaging/disengaging of the rear end (2P) of the threaded tie-rod (2) to/from the sleeve (30).
The system of claim 3 or 4, characterised in that the groove (6) fashioned at the rear end (2P) of the threaded tie-rod (2) comprises :
a first straight portion (61) which extends inclined with respect to the axis (X) of the threaded tie-rod (2), and a second straight portion (62), connecting to the first portion (61), which extends perpendicularly with respect to the axis (X) of the threaded tie-rod (2).
The system according to claim 5, characterised in that during the engaging step of the rear end (2P) of the threaded tie-rod (2) with the sleeve (30), the insert (5) involves in succession the first straight portion (61) of the groove (6) and then the second portion (62); during the step of disengaging the rear end (2P) of the threaded tie-rod (2) from the sleeve (30), the insert (5) involves in succession the second straight portion (62) of the groove (6) and therefore the first straight portion (61).
The system of one of claims from 4 to 6, characterised in that it comprises:
a first truncoconical portion (71) internally conformed by the front head (30A) of the sleeve (30); a second truncoconical portion (72) conformed by the rear end (2P) of the threaded tie-rod (2); and in that in the alignment configuration of the threaded tie-rod (2) with the axis (Y) of the sleeve (30), the second truncoconical portion (72) goes to abut against the first truncoconical portion (71), and the elastic means (9) press the insert (5) against a portion of the groove (6).
An electro-hydraulic gun for deforming fixing elements, comprising:
- an activating trigger (8);

- a threaded tie-rod (2) for engaging, with a front end (2A) thereof, in a threaded axial hole of a deformable fixing element;

- a tie-rod seating (3) in which the rear end (2P) of the threaded tie-rod (2) can be positioned;

- an oil-dynamic system comprising an oil-dynamic fluid, a cylinder, internally of which a piston slides, and activating means destined, by the action of the oil-dynamic fluid, to axially translate the threaded tie-rod in such a way as to determine a plastic deformation of a predetermined portion of the fixing element so as to block the fixing element to a corresponding wall;

- a first electric micromotor for commanding compression and discharge runs of the piston internally of the cylinder;

- a second electric micromotor able to set the threaded tie-rod (2) in rotation so as to engage or disengage the threaded tie-rod (2) to or from the threaded axial hole of the fixing element;

- at least an electronic control unit able to control and command the first and second electric micromotors;

- supply means for providing electrical energy to the electronic control unit and the first and second electric micromotors;

- a system for coupling/decoupling the threaded tie-rod 2 to and from the tie-rod seating (3) according to one of claims from 1 to 7.
A pneumo-hydraulic gun for deforming fixing elements, comprising:
- an activating trigger;

- a threaded tie-rod (2) for engaging, with a front end (2A) thereof, in a threaded axial hole of a deformable fixing element;

- a tie-rod seating (3) in which the rear end (2P) of the threaded tie-rod (2) can be positioned;

- a source of compressed air;

- an oil-dynamic system comprising an oil-dynamic fluid, a cylinder, internally of which a piston slides, and activating means destined, by the action of the oil-dynamic fluid, to axially translate the threaded tie-rod in such a way as to determine a plastic deformation of a predetermined portion of the fixing element so as to block the fixing element to a corresponding wall;

- a pneumatic motor able to set the threaded tie-rod in rotation to right or left so as to engage or disengage the threaded tie-rod to or from the threaded axial hole of the rivet;

- a pneumatic system, supplied by the source of compressed air, comprising valve means for commanding supply to the motor and for commanding the compression and discharge runs of the piston internally of the cylinder, respectively destined to raise the pressure of the oil-dynamic fluid up to a maximum predetermined value, and to reduce the pressure of the oil-dynamic fluid.

- a system for coupling/decoupling the threaded tie-rod 2 to and from the tie-rod seating (3) according to one of claims from 1 to 7.