ITBO20080117A1 - ELECTRO-HYDRAULIC PISTOL DEVICE WITH ELECTRONIC CONTROL FOR THE DEFORMATION OF FIXING ELEMENTS - Google Patents

Abstract

The electro-hydraulic pistol device (100) comprises: a first electric micro-motor (1 ), for setting in right-wise or left-wise rotation a threaded rod (2), respectively for engaging or disengaging the rod (2) from a rivet (3); a hydraulic system (4) in which a fluid (F) pushes a cursor (40), associated to the rod (2) for impressing thereon an axial translation which causes plastic deformation of a predetermined portion of the rivet (3), such as to block the rivet (3) to a corresponding wall (P); a second electric micro-motor (5), for commanding a piston (50) destined to compress the fluid (F). An electrical circuit (6) is associated to the above organs, which electrical circuit (6) is managed by a control unit (60), to which are connected: a first micro-switch (61) activated by the rod (2) for activation of the first micro-motor (1) in a right-wise direction; a second micro-switch (62), destined to be activated by a trigger (63) after deactivation of the first micro-switch (61), for activating the second micro-motor (5), first in a direction, for compressing the fluid (F), and then in another direction, for reducing the pressure of the fluid (F), as well as for activating, in phase relation, the first micro-motor (1) in a left-wise rotation; supply means (7) for the circuit (6) and the micro-motors (1, 5). The left-wise rotation of the first micro-motor (1) and the rod (2) proceeds as long as the trigger (63) is kept pressed.

Description

ELECTRO-HYDRAULIC GUN DEVICE WITH ELECTRONIC CONTROL FOR THE DEFORMATION OF FIXING ELEMENTS

DESCRIPTION OF THE INVENTION

The present invention is part of the technical sector of riveting guns, with particular reference to those with servo-assisted operation, used for rivets having a cylindrical shape, a partially threaded axial hole, a stop collar in correspondence with a head and a portion suitably weakened in the which plastic deformation is localized.

The aforementioned rivets are intended to stably join two walls, for example in place of spot welding, or to constitute a threaded anchor bush, of adequate strength, for structures made with materials that are too soft or too thin to give rise to sufficiently strong threads. resistant.

The aforementioned rivets can be of non-negligible dimensions, and for their installation, equipment capable of exerting a high compressive force on them is required.

A known riveting gun, built by the same Applicant in accordance with a corresponding Patent Application for Industrial Invention, BO2007A000311, comprises a body and a handle in which are housed:

- a pneumatic motor, designed to rotate a threaded rod in right or left rotation, respectively to engage or disengage the latter from the axial threaded hole of one of said rivets;

- an oleodynamic system, adapted to impart an axial translation to the motor-tie rod assembly, to determine the plastic deformation of a predetermined portion of said rivet, so as to lock it to a structure;

- a pneumatic thrust amplifier, actuating a piston provided to compress the fluid of said hydraulic system;

- a pneumatic system, in which an auxiliary valve is provided, operated in opening by said tie rod; a main valve, activated in opening by a relative trigger;

- a hydropneumatic exchange valve, connected to the aforementioned hydraulic and pneumatic systems, in which there are provided: first members suitable for detecting the pressure of the hydraulic fluid; second organs, designed to switch the delivery of compressed air from the pneumatic thrust amplifier to the pneumatic motor, upon reaching a predetermined maximum pressure of the hydraulic fluid;

- an emergency command, designed to put the pneumatic motor in left rotation. The operation of said gun is as follows:

- the rivet is placed in the hole prepared for this purpose in the structure, with the relative collar against the latter, or, alternatively, the same rivet is manually positioned in front of the pistol rod;

- the tie rod is inserted into the axial hole of the rivet, up to the beginning of the thread of the latter, thus causing an axial thrust on the tie rod, towards the gun body, which causes the auxiliary valve to open, which allows sending compressed air to the motor, turning it to the right to screw the rivet; when the collar of this reaches the stop of the front head of the body, the automatic closing of the auxiliary valve is determined and therefore the engine stops;

- pressing the trigger commands the opening of the main valve, which allows the sending of compressed air to the thrust amplifier, through the hydropneumatic exchange valve, with a consequent increase in the pressure of the hydraulic fluid and the start of the axial translation of the motor unit - tie rod;

- keeping the trigger pressed, the translation continues, causing a progressive compression of the rivet which therefore deforms towards the outside, in the weakened portion, to define an annular edge, adhering to the facade of the structure opposite to that on which the collar rests, with this resulting in the locking of the rivet;

- always with the trigger pressed, when the maximum pressure foreseen for the hydraulic fluid is reached, the second parts of the hydropneumatic exchange valve intervene, which interrupt the flow of compressed air towards the thrust amplifier and send it to the pneumatic motor, placing it in left rotation; at the same time, the air contained in the thrust amplifier is discharged to the outside;

- the left rotation of the motor is transmitted to the threaded rod which is unscrewed from the rivet, now locked to the structure:

- the operator releases the trigger when the tie rod has disengaged from the rivet.

The riveting gun just described works very well, but necessarily requires a source of compressed air to which it can be connected; its use is therefore precluded where this source is not available.

The object of the present invention is therefore to propose an electro-hydraulic gun device with electronic control for the deformation of fastening elements, therefore not requiring connection to a source of compressed air.

Another purpose of the invention is to offer an electro-hydraulic pistol device which has an operating logic that is entirely similar to that of the known type pistol mentioned in the introduction.

Another object of the invention relates to the desire to propose an electro-hydraulic pistol device which can be produced in numerous variants, different for the type of electrical power supply envisaged and / or for the construction architecture, with components that can be housed in the body and in the handle. or external to these.

A further purpose of the invention consists in the possibility of offering particularly compact and lightweight versions of the electro-hydraulic pistol device, thanks to the external location of components.

The characteristics of the invention will be made clear in the following description of preferred embodiments of the invention, in accordance with what is reported in the claims and with the aid of the attached drawing tables, in which:

• Fig. 1 illustrates an embodiment of the electro-hydraulic gun device in question, in a schematic sectional side view;

• Fig.2 shows a section on the II-II plane of Fig.1;

• Fig.3 shows a section on the III-III plane of Fig.1;

• Figs. 4 to 11 show views similar to Fig. 1, with the electro-hydraulic device in the most salient operating phases.

With reference to the aforementioned figures, 100 indicates a first embodiment of the electro-hydraulic pistol device in question, as a whole; in the remainder of the description, for greater clarity, said device 100 is simply referred to as a gun.

The gun 100 comprises a body 101 and a handle 102 in which are housed: - a first electric micromotor 1, able to rotate a threaded rod 2 by means of first transmission members 11, respectively to engage or disengage the latter from the threaded axial hole 3A of one of said rivets 3;

- an oleodynamic system 4 comprising a cylinder 51, containing a fluid F and connected to a chamber 41, in which a slider 40 is slidable to impart an axial translation to the tie rod 2, to determine the plastic deformation of a predetermined portion of said rivet 3, so as to lock it to a corresponding wall P;

- a second electric micromotor 5, able to control, by means of second transmission members 52, the forward and return stroke of a piston 50, designed to compress, in said forward stroke, the fluid F of said hydraulic system 4 in the cylinder 51;

- an electric circuit 6, in which are provided: a control unit 60; a first microswitch 61, adapted to be operated by said tie rod 2 for the activation of the aforementioned first micromotor 1 so that the tie rod 2 turns right; a second microswitch 62, adapted to be operated by a relative trigger 63, for the activation of the aforementioned second micromotor 5 first in one direction and then in the other and, in a phase relationship determined by the aforementioned control unit 60, of the aforementioned first micromotor 1 in opposite rotation to the first;

- accumulators 7, associated with an ON / OFF switch, not shown, for supplying electrical energy to said electric circuit 6 and, through this, to the aforementioned first and second micromotors 1, 5.

The gun 100 also comprises an emergency button control, not shown in detail but preferably arranged with a position and / or conformation protected from accidental operations, associated with the aforementioned electric circuit 6 and provided to activate the aforementioned first micromotor 1 so that the tie rod 2 is in left rotation, in the conditions described below.

The aforementioned first transmission members 11 consist, for example, of a train of gears also having the function of a speed reducer; preferably, said members 11 determine the same direction of rotation for the micromotor 1 and for the tie rod 2 (Figs. 2 and 3).

The aforesaid second transmission members 52 consist, for example, of a planetary reduction gear.

The operation of the gun 100 is now described for the application of a rivet 3 to a wall P, starting from the inoperative position of Fig. 4, in which:

- the first and second micromotors 1, 5 are stationary;

- the pressure in the hydraulic system 4 is at a minimum, with the piston 50 in its lowered position in the cylinder 51 and the slider 40 advanced into the chamber 41, towards the front head 101A of the body 101, due to the action of a relative contrast spring 42;

- the switch associated with the accumulators 7 in the ON position.

The rivet 3 is placed in the hole prepared for this purpose in the wall P, with the relative collar 3B abutting against the latter, or, alternatively, the same rivet 3 is manually positioned in front of the tie rod 2 of the gun 100 (see again Fig. 4).

Similarly to the known riveting gun, mentioned in the introduction, the tie rod 2 is inserted into the axial hole 3A of the rivet 3, up to the beginning of the threading of the latter, thus causing an axial thrust on the threaded tie rod 2, towards the body 101 of the gun 100, which causes the first microswitch 61 to be activated; the closing of the contact in the latter provides the signal to the control unit 60 to activate the first micromotor 1 in the appropriate direction, placing the tie rod 2 in right rotation in order to screw the rivet 3.

When the collar 3B of this reaches the abutment of the front head 101A of the body 100, the tie rod 2 is drawn outwards, releasing the first microswitch 61, thereby causing the first micromotor 1 to stop (Fig.5).

By pressing the trigger 63, the second microswitch 62 is activated and the control unit 60 starts the automatic operating cycle of the gun 100 (Fig. 6).

The aforementioned second micromotor 5 is then activated in the appropriate direction to determine the said forward stroke of the piston 50 in the cylinder 51, with a consequent increase in the pressure of the oleodynamic fluid F in the chamber 41 of the slider 40 (Fig. 7).

By keeping the trigger 63 pressed, the plunger 50 continues to rise, while the fluid F under pressure overcomes the resistance of the contrast spring 42 and pushes the cursor 40 to move back, together with the associated threaded rod 2.

The translation continues, causing a progressive compression of the rivet 3 which therefore deforms towards the outside, in the weakened portion, to define an annular edge 3C, adhering to the face of the wall P opposite to that on which the collar 3B rests, thereby determining locking the rivet 3 (Fig. 8).

The increase in pressure in the hydraulic system 4 increases the resistance to the rise of the piston 50, which involves a proportional increase in power absorption by the second micromotor 5.

The value of said absorption is constantly monitored by the control unit 60, since the force exerted on the tie rod 2 to deform the rivet 3 is related to it by means of suitable parameters.

On the basis of the maximum force for which the gun is to be calibrated, the maximum absorption peak that the second micromotor 5 must reach is calculated and the corresponding data is stored in the control unit 60.

When the instantaneous absorption detected equals the maximum expected value, and therefore having reached the predetermined deformation force, the control unit 60 reverses the rotation of the same second micromotor 5, with consequent inversion of the movement of the piston 50 (Fig. 9).

What has just been said causes a sudden drop in the pressure of the hydraulic fluid F, thereby ceasing the retraction of the slider-tie rod assembly and therefore the stress on the rivet 3.

While the piston 50 continues its descent, due to the action of the second micromotor 5, the contrast spring 42 again prevails over the force determined by the pressure of the fluid F and pushes forward the cursor 40 and the tie rod 2.

The control unit 60, with a suitable phase relationship with respect to the descent of the piston 50, also starts the first micromotor 1, to set the threaded rod 2 in left rotation so that it unscrews from the rivet 3 now locked to the wall P (Fig. 10).

The second micromotor 5 is kept in motion until the piston 50 reaches its lowered starting position, after which it is automatically deactivated by the control unit 60 (see again Fig. 10); the signal certifying the achievement of said position can be given by an end-of-stroke sensor (not shown), or by the increase in absorption of the micromotor 5 following the interception of a mechanical limit switch 53 integral with the same piston 50.

The rotation of the first micromotor 1, on the other hand, remains as long as the trigger 63 is kept pressed, therefore the rotation of the tie rod 2, for unscrewing the rivet 3 just applied, continues for the time established by the operator.

When the trigger 63 is released, with consequent stopping of the first micromotor 1, the foreseen operating program is completed (Fig. 11).

At this point the gun 100 is again in the condition described with reference to Fig.4, with the control unit 60 set up for a new cycle.

A particularly skilled operator, therefore, is able to best synchronize the disengagement of the tie rod 2 with the stop of the micromotor 1, in order to make the gun 100 immediately ready for another rivet 3 previously positioned on the wall P.

If the trigger 63, by mistake or other, is released before the disengagement of the tie rod 2 has taken place, unscrewing can be completed by pressing the aforementioned emergency command, to reactivate the micromotor 1 with further left rotation of the tie rod 2.

It should be emphasized that the gun 100, as described, is not affected in the least by a possible maneuver error if, following an early release of the trigger 63, a new pressure follows on it.

The control logic of the control unit 60, in fact, can be programmed to continue the interrupted cycle if, for example, the release occurs during the deformation phase of the rivet 3.

If, on the other hand, the maneuver error concerns the final unscrewing phase, with a subsequent pressure on the trigger 63 instead of activating the aforementioned emergency command, the gun repeats the automatic pulling cycle on the tie rod 2 without causing unwanted stresses on the rivet. 3 applied, as on reaching the same previous maximum pressure of the fluid F, the control unit 60 interrupts the action and starts unscrewing, so that the only drawback that occurs is a modest waste of time.

For the electro-hydraulic gun device in question, other embodiments are provided in addition to the one illustrated and described up to now.

In a second embodiment, not shown, it is provided that the accumulators 7 and possibly also the control unit 60 are housed in a module external to the body of the gun, to contain the weight and overall dimensions of the latter and make it easier to handle. use.

In a third embodiment, also not illustrated, it is envisaged to eliminate the accumulators and withdraw electricity from a mains socket, with the interposition of a suitable transformer / rectifier, in order to obtain unlimited working autonomy. also in this case combined with a consistent weight reduction.

Of course, with regard to the latter solution, the total independence of the device from external energy sources is lost, but it is quite clear that it is much easier to have a power outlet than a source of compressed air. In a further embodiment, not illustrated, it is envisaged to combine the constructive characteristics of the two embodiments mentioned above, by providing a module external to the body of the gun which contains, in addition to the accumulators and the control unit, the transformer / rectifier for the '' mains power supply and possibly a device for recharging the same accumulators.

From the above it can be understood how the electro-hydraulic pistol device proposed fully achieves the intended purposes, in particular to obtain an operating logic completely similar to that of the known type gun mentioned in the introduction, without requiring power supply. with compressed air.

The constructive possibilities given by the choice of electric drives allow to easily set up, and without any contraindication on the functioning, numerous constructive variants, able to satisfy needs otherwise destined to remain unanswered.

Thanks to the external location of components such as accumulators, in fact, it is possible to obtain considerable benefits in terms of compactness and lightness of the device, with obvious advantages for its use.

It is understood, however, that what has been said above has an exemplary and not limiting value, therefore any detailed changes, which would be necessary subsequently to introduce, for constructive and / or functional reasons, are considered as of now to fall within the same protective scope defined by the claims reported below.

Claims (15)

CLAIMS 1) Electro-hydraulic pistol device with electronic control for the deformation of fastening elements, of the type comprising: a threaded tie rod 2, able to engage with the threaded axial hole 3A of a rivet 3; a hydraulic system 4, adapted to impart an axial translation to said threaded tie rod 2, to determine the plastic deformation of a predetermined portion of the aforementioned rivet 3, so as to lock it to a corresponding wall P, with said device 100 characterized in that it comprises : a first electric micromotor 1, adapted to make the said threaded tie rod 2 rotate right or left, respectively to engage or disengage the latter from the aforementioned axial threaded hole 3A; means 40, associated with said tie rod 2 and adapted to impart the aforementioned axial translation to the latter, for the action of the oleodynamic fluid F of said system 4; a second electric micromotor 5, adapted to control the compression and discharge strokes of a piston 50 inside a cylinder 51, respectively intended to raise the pressure of the fluid F of said hydraulic system 4, up to a predetermined maximum value, and to break down the same pressure; an electric circuit 6, managed by a control unit 60, in which a first microswitch 61 is provided, adapted to be operated by said tie rod 2 for the activation of the aforementioned first micromotor 1, so that the same tie rod 2 is in rotation right, and a second microswitch 62, adapted to be operated by a trigger 63, after the deactivation of said first microswitch 61, for the activation of the aforementioned second micromotor 5, first in one direction and then in the other, as well as for the activation, in phase relation with the activation of the discharge stroke of the aforementioned piston 50, of the aforementioned first micromotor 1, so that the aforementioned tie rod 2 is in left rotation; power supply means 7, for supplying electrical energy to said electric circuit 6 and, through this, to the aforementioned first and second micromotors 1, 5. 2) Device according to rev. 1, characterized by the fact that said means 40 consist of a slider, slidably inserted into a chamber 41 and subject, on one side, to the action of a contrast spring 42 and, on the other hand, to the action of the oleodynamic fluid F of said system 4. 3) Device according to rev. 1, characterized in that the aforementioned control unit 60 is provided with means for detecting the instantaneous power absorption of the aforementioned second micromotor 5, and with calculation means for relating said absorption value with the aforementioned pressure of the oleodynamic fluid F . 4) Device according to rev. 1, characterized in that the first transmission members 11 are interposed between the aforementioned first micromotor 1 and said threaded tie rod 2. 5) Device according to rev. 4, characterized by the fact that said first transmission members 11 consist of a train of gears designed to reduce the number of revolutions from the input to the output of the motion. 6) Device according to rev. 1, characterized in that second transmission members 52 are interposed between said second micromotor 5 and said piston 50. 7) Device according to rev. 6, characterized in that said second transmission members 52 consist of a planetary reduction gear. 8) Device according to rev. 1, characterized in that an emergency button control is provided, associated with the aforementioned electric circuit 6 and provided to activate the aforementioned first micromotor 1 so that the tie rod 2 is in left rotation. 9) Device according to rev. 1, characterized in that said power supply means 7 is associated with a two-position switch, respectively for connecting and excluding the same means 7 to and from the aforementioned electrical circuit 6. 10) Device according to claim 1 or 9, characterized in that said power supply means 7 are housed in the body 101 and in the handle 102 of the same device 100. 11) Device according to claim 1 or 9, characterized in that said power supply means 7 are housed in a module external to the same device 100. 12) Device according to rev. 1 or 9 or 10 or 11, characterized in that said feeding means 7 consist of accumulators. 13) Device according to rev. 1 or 9 or 10 or 11, characterized in that said power supply means 7 consist of a transformer / rectifier adapted to be connected to an external electric line. 14) Device according to claim 1, characterized by the fact that said control unit 60 is housed in the body 101 and in the handle 102 of the same device 100. 15) Device according to claim 1, characterized in that said control unit 60 is housed in a module external to the same device 100.