EP0072713A2 - Unfastening device for screw fasteners - Google Patents

Abstract

Screw clamp pin extractor for clamping pins of the type having a body fastened to a spreader lying between two tongs secured to a screw, and a nut acting against a spring. The extractor comprises a pneumatic motor, a nose portion engaging the clamp pin and carrying a sleeve brought into contact with an assembly of sheets, said extractor comprising moreover an internal mechanical system. When the motor rotates for unscrewing pins the device is locked on the pin and the nut of same can be unscrewed, and thereafter, the pin is extracted through the action of a jack. The extractor can be attached as desired either to the body of the usual manual screwing machine or a robotic head known in itself.

Description

• 1/ mise en place de l'agrafe dans le trou de perçage puis vissage de l'écrou de l'agrafe permettant l'accostage des tôles constituant l'assemblage.
• 2/ dévissage de l'écrou suivi de l'extraction de l'agrafe de son logement.

The present invention relates to screw pinning staples which are used in the following manner, in the aeronautical field in particular:

• 1 / fitting the clip into the drilling hole then screwing the nut of the clip allowing the sheets constituting the assembly to come into contact.
• 2 / unscrewing the nut followed by extracting the clip from its housing.

These two sequences are carried out successively in order to allow the interposition product disposed between the sheets to polymerize or else the assembly to position itself correctly when said assembly does not include such an interposition product.

• - le pas de pose des agrafes est parfois réduit, ce qui nécessite des nez de vissage et de dévissage de faible encombrement,
• - le produit d'interposition entre tôles qui est de consistance caoutchouteuse, "bave" dans les trous ce qui pose des difficultés considérables d'extraction des agrafes après polymérisation.

However, these two implementation sequences pose a certain number of practical problems:

• - the stapling pitch is sometimes reduced, which requires screwing and unscrewing noses of small bulk,
• - the interposition product between sheets which is rubbery in consistency, "drooling" in the holes, which poses considerable difficulties in extracting the staples after polymerization.

However, while the pneumatic screwing and unscrewing materials currently proposed comprise reduced-sized noses suitable for most of the cases encountered, the problem of extracting staples does not remain, to the knowledge of the Applicant, of satisfactory solution to date. Indeed, this operation is always carried out by hand, sometimes in areas of high density of staples, which presents, in addition to the hazards of manual removal, certain dangers of injury to operators.

In addition, this manual design does not predispose to the evolution towards the robotics stage where all operations will then have to be carried out without human intervention.

All the attempts made in this area and known to the Applicant have brought solutions leading to significantly increasing the size of the nose bringing, by the same, the use .possible only in areas with low densities of staples.

The present invention provides an automatic device for unscrewing and depositing a pinning screw clip, which does not have any of the aforementioned drawbacks.

A first advantage of the device according to the invention lies in its simplicity of implementation as a hand pneumatic unscrewer nose used in most cases in the aeronautical field.

A second advantage is that this nose is also adaptable to the arms of the robots which can be, moreover, the same as those which pierce the staple holes and which lay the rivets for final fixing.

A third advantage consists in that this nose is of reduced size, thus allowing access to the staples placed in the areas of high density.

Historically, the idea of equipping pinning staples with a hexagon system on the clamping nut seems to date back to 1962 through American patent 3,024,682.

This had, in its time, the advantage of allowing the installation of staples by pneumatic guns which were already very widespread at that time in the aeronautical environment.

Furthermore, it was taught in this patent that the body of the clip could also be held and immobilized by a hexagonal conformation of the body, which meant that the nose of the screwdriver could then comprise two coaxially rotating tubes, each terminated. , by a hexagonal imprint; the inner tube for the nut and the outer tube for the body of said clip.

The extraction of the staple not being sought, it was always possible to ensure the simple gripping of the staple by bringing the two hexagon parts of the nut and the staple body into coincidence.

The problem of manual extraction of staples was solved in American patent 3.331268 of 1967 which showed how it was possible using a third external tube with hexagonal end to produce, after a rotation of 1/12 of a turn, the gripping of the body of the clip by pressing said last tube under the tips of the sides of the hexagon of the clip.

From then on the extraction of the staples was possible but remained dependent on both the skill of the operator as well as the extent of the imprisonment of the staple in its hole, due to the quantity of product. polymerized interposition that may have spread there.

It should be noted in addition that the pneumatic screwdrivers would benefit from a significant improvement consisting in putting the engine in stalling in screwing or unscrewing as soon as the appearance of a predetermined torque, which had the advantage of considerably reducing the consumption of air without damaging the material.

In general, the rest of the text will show how, by virtue of the implementation of the invention, the prior techniques can be improved to lead to an advanced device allowing the unscrewing and the extraction of the staples. fully automatic pinning.

In any case, the invention will be clearly understood in the following text which will show how, in support of the appended drawings, it can be implemented, both with regard to its application on hand-held screwing machines and on robot arm.

• la figure 1 montre schématiquement et en coupe axiale, une agrafe d'épinglage à vis en regard de son trou d'agrafage ;
• la figure 2 montre schématiquement et en coupe axiale la même agrafe dans son trou avant polymérisation du produit d'interposition ;
• la figure 3 montre l'agrafe en position après polymérisation :
• la figure 4 montre schématiquement comment l'agrafe est extraite de son trou ;
• la figure 5 est une vue en coupe axiale d'un nez de dévissage - extraction conforme à l'invention ;
• la figure 6 est une vue montrant un détail agrandi, selon flèche A de la figure 5 ;
• la figure 7 est une vue montrant un détail agrandi, selon flèche B de la figure 5 ;
• la figure 8 est une vue schématique en coupe du système de pression différentielle ;

et la figure 9 est une vue en plan d'une machine à main de dévissage et extraction d'agrafe selon l'invention.In the drawings:

• Figure 1 shows schematically and in axial section, a screw pinning staple opposite its stapling hole;
• Figure 2 shows schematically and in axial section the same clip in its hole before polymerization of the interposition product;
• FIG. 3 shows the clip in position after polymerization:
• Figure 4 shows schematically how the clip is extracted from its hole;
• Figure 5 is an axial sectional view of a unscrewing nose - extraction according to the invention;
• Figure 6 is a view showing an enlarged detail, along arrow A of Figure 5;
• Figure 7 is a view showing an enlarged detail, along arrow B of Figure 5;
• Figure 8 is a schematic sectional view of the differential pressure system;

and FIG. 9 is a plan view of a hand machine for unscrewing and extracting staples according to the invention.

Referring to FIG. 1, it can be seen that a screw pinning staple essentially comprises on the one hand, a hollow body 1 which may be made of plastic and which is integral with a spacer f located between the clamps 2 'and 2 "secured to a screw 2, and on the other hand to a spring 3 and a nut 4 engaged on the screw 2 and which acts against said spring 3.

The usual pneumatic system moreover comprises a body 5 receiving the motor (not shown) which drives in rotation an inner tube 6 provided with a hexagon at its end while two other tubes, one of which is external marked 7 and finished in its end by a hexagon is fixed by its connection to 5 and, the other, marked 8 and which is intermediate is also terminated at its end by an imprint also hexagonal.

As soon as the hexagonal part of the body 1 of the staple is engaged in the corresponding imprint of the tube 7, the staple is in place and is locked when the tube 8 has turned 1/12 of a turn so that the the hexagon footprint plates of 8 are located under the points of the hexagon in the hexagonal part of the clip.

The clip thus grasped and locked is introduced into the hole of the assembly consisting of the sheets 9 and 10 and of the interposition product 11.

According to the second phase of the operation shown in FIG. 2, the nut 4 is screwed up to a preset torque so that the pliers 2 'and 2 ", while moving away, come to hang on the opposite side of the assembly thus producing under the effect of the spring 3 the approach of the sheets 9 and 10 towards one another. The nose can then be evacuated after rotation of 1/12 of a turn of the tube 8 relative to the tube 7.

In the third phase shown in Figure 3, the clip is left in place for the duration of the polymerization of the product 11 while the spring 3, restoring its energy tends to produce the approximation of the sheets 9 and 10 in the area of hole during this same time.

According to the fourth phase very particularly foreshadowing the implementation of the invention, the nose is replaced on the clip to lead, after proper unscrewing of the nut 4, to the complete extraction of the latter.

It should be noted that this FIG. 4 is well representative of the problems encountered prior to the application of the invention insofar as the excess of product 12 was lodged in the hole itself as a result of the pressurization of the sheets, thereby making it extremely difficult to extract the clip from its hole.

Indeed, it was necessary to exert a significant traction in the direction F of FIG. 4, on the nose to obtain the extraction of the clip, this traction causing correlatively a bossing of the assembly such as that is shown in dotted lines in this same figure 4.

The unscrewing and extraction nose according to the invention comprises, as will be explained below, a part bearing on the assembly while a jack comes to evacuate the clip from its hole as soon as the unscrewing phase of the nut.

Such a nose essentially comprises, as can be seen from FIG. 5, a motor part, a bushing part and a piston part.

According to the invention, the motor part is known per se, and can result either from an adaptation in hand pistol configuration, or from a more advanced configuration in an automated station in robotic applications.

In both cases and according to this figure 5 the motor air begins by rotating the bushing 13 via the axis 14 and the marker driver 15.

This socket 13 is screwed by a thread 13 'not to the left, into another socket 16 which can rotate angularly by 30 ° to lock or unlock under the effect of friction in the screw threads and by the fact of the light formed in the part 16 as shown in detail in FIG. 6.

The sleeve 16 is moreover immobilized in translation, as can be seen in FIG. 7, by the axis screw 17 which only allows its single rotation of 30 °.

Locking takes place under the effect of the rotation of the sleeve 16 in front of the lock 18 which is itself immobilized in rotation relative to the external body 19 by means of the screw 20 which also subjects it in translation relative to the socket 16.

The body 19 is also immobilized in rotation on the piston 21 via the axis of the stop ring 22.

The piston 21 is immobilized in rotation relative to the inner cylinder guide 23 by the pin screw 17.

In the unscrewing phase, the sleeve 13 advances axially in the sleeve 16 by the fact of the presence of the left-hand thread 13 'and this, until the screw 24 comes to abut at the end of the axial light 24' made in part 15 which causes the engine to stall.

The sleeve 13 causes in its axial displacement, the axis 14 which then pushes on the screw of the staple marked 2.

It should be noted that said socket 13 comprising a ring 13 "with internal hexagonal imprint and having a thread in the socket 16 which is not less than the pitch of the nut 4 of the clip, advances faster than recedes said nut 4 and that, as a result, the spring 25 is then compressed under the effect of said ring 13 'which ejects, during unlocking, the clip from the nose of the screwdriver.

The engine part has two conduits, one 26 communicating the pressure from the PM motor to the differential marked 28 in FIG. 8, the other marked 27 bringing the pressure of said differential 28 to the cylinder through the chamber 21 '.

The stalling of the motor resulting from the advance of the screw 24 coming into abutment at the bottom of the lumen 24 'according to FIG. 5, causes a pressure difference on the differential 28 through the conduit 26.

The pressure, having increased on the motor side PM, and the control pressure PT being fixed, allows differential differential 28 to allow air to pass through the duct 27 to the chamber 21 'of the O-ring cylinder 32 and 33.

The piston 21 thus actuated pushes on the external body 19 which consecutively moves the clip away from the surface of the assembly formed by the sheets 9 and 10.

This is obtained by the fact that the socket 16, which carries an internal hexagon at its end, can rotate _{30 ° (} or a _1/12 of a turn) in front of the other hexagon ring or latch 18 thanks to the presence of the axis screw 20, as shown in detail in FIG. 6.

This 1/12 turn rotation is made possible due to the friction of the threads of the thread 13 ', between the sockets 13 and 16, as has already been mentioned previously.

• - le corps 19 appuie sur l'assemblage 9-10 (par l'intermédiaire d'une bague 35 qui peut être en plastique) ;
• - l'agrafe est maintenue en place par le verrou 18 ;
• - l'appui d'extraction est assuré par le fait que la partie six pans de la douille 16 accroche les angles six pans de l'agrafe 1, après rotation de 1/12 de tour de la douille 16 par rapport à la vis axe 20 ;
• - le mouvement axial de traction est assuré par le déplacement axial de la douille 16 par rapport à la bague 35 (ou le corps 19 qui lui est lié).

In this way, extraction of the clip is made possible since:

• - The body 19 presses on the assembly 9-10 (via a ring 35 which can be made of plastic);
• - The clip is held in place by the latch 18;
• - the extraction support is ensured by the fact that the hexagonal part of the socket 16 hooks the hexagonal angles of the clip 1, after 1/12 of rotation of the socket 16 relative to the axis screw 20;
• - The axial traction movement is ensured by the axial displacement of the sleeve 16 relative to the ring 35 (or the body 19 which is linked to it).

When the clip is extracted from its hole, it suffices to rotate the motor in the direction of screwing, which has the effect of unlocking the sleeve 16 as a result of friction in the threads 13 'and which, moreover, causes expulsion. During this time, the jack is no longer supplied and the spring 34 returns it to its initial position.

At the end of the cycle, the socket 13 moves back until the axis 14 abuts on the driver 15 from which the stalling of the motor results, which means that the stapler is in the rear position and ready to extract the next clip.

The differential 28 according to FIG. 8 has a flexible membrane 39 defining two chambers

the one 40 of PM pressure arrival, by the return pipe of the engine by the pipe 26, and returning to the jack by the pipe 27, the other 41 receiving the pressure witness PT arriving by the pipe 42 and which can possibly be adjusted by the needle screw 42 '.

The differential 28 can be fixed as desired, either on the lower part of the stock 36 of an air pistol of the usual type (as is more particularly shown in FIG. 9), or on a robot head known per se 43 ( not shown further in this description).

According to the first solution represented in FIG. 9, the operator apprehends in the usual way the stick 36 provided at its end with the pressure differential 28 while this differential is itself connected to the air intakes by the conduits 26 (PM ) and 27 (PV) passing through the trigger guard 44 further constituting physical protection of the operator's hand.

• - lorsque le moteur tourne au dévissage :
• . la pression témoin PT réglée dans la chambre 41 par la vis pointeau 42' ;
• . la pression du moteur PM est inférieure à PT dans la chambre 40 ;
• - lorsque le moteur tourne au vissage :
• . la pression du moteur PM est nulle dans la chambre 40 ;
• . l'air n'alimente pas le vérin et la membrane 39 est dans la position représentée en traits forts sur la figure 8.
• - lorsque le moteur est calé au dévissage :
• . la pression témoin PT reste constante dans la chambre 41 ;
• . la pression du moteur PM est supérieure à PT dans la chambre 40 ;
• . la membrane 39 est dans la configuration représentée en pointillé sur la figure 8 et le vérin se retrouve alimenté en air par le conduit 27 ;
• - lorsque le moteur est calé au vissage :
• . la pression témoin PT reste constante dans la chambre 41 ;
• . la pression du moteur PM est nulle dans la chambre 40 ;
• . l'air n'alimente pas le vérin, et la membrane 39 est dans la configuration représentée en trait plein sur la figure 8.

The role of the pressure differential is multiple:

• - when the engine is running when unscrewed:
• . the witness pressure PT set in chamber 41 by the needle screw 42 ';
• . the pressure of the motor PM is less than PT in the chamber 40;
• - when the engine is running when screwing:
• . the pressure of the PM motor is zero in the chamber 40;
• . the air does not supply the jack and the membrane 39 is in the position shown in strong lines in FIG. 8.
• - when the engine is stalled when unscrewed:
• . the control pressure PT remains constant in chamber 41;
• . the pressure of the motor PM is greater than PT in the chamber 40;
• . the membrane 39 is in the configuration shown in dotted lines in FIG. 8 and the jack is supplied with air by the conduit 27;
• - when the engine is stalled when screwing:
• . the control pressure PT remains constant in chamber 41;
• . the pressure of the PM motor is zero in the chamber 40;
• . the air does not supply the jack, and the diaphragm 39 is in the configuration shown in solid lines in FIG. 8.

In this way it can be seen that the automatic sequences of unscrewing-extracting staples or unclipping which is identical, are provided entirely by the device described above in accordance with the invention.

In addition, it can also be seen that the nose 5 can be fixed by a sleeve 30 either on a body 36 of a conventional hand-held screwdriver as shown in FIGS. 5 and 9, or on a robot head known per se and symbolized by the item 43.

• - perce les trous ;
• - positionne et visse les agrafes ;
• - désagrafe (conformément à l'invention) ;
• - pose les rivets (ou boulons) définitifs,seules les têtes étant changées en fonction des opérations envisagées.

It is obvious that, in the latter case, the robot used for the stapling operation could be the same as that which:

• - drills holes;
• - positions and screws the staples;
• - stapler (according to the invention);
• - installs the final rivets (or bolts), only the heads being changed depending on the operations envisaged.

It goes without saying that the present invention has only been described and shown as a preferred example and that technical equivalences may be made in its constituent elements without going beyond the ambit of said invention, which is specified in the following claims.

Claims (5)

, 1. Screw pinning staple remover of the type comprising a body (1) secured to a spacer (1 ') located between two clamps (2'-2 ") secured to a screw (2) and a nut (4) acting against a spring (3), characterized in that it comprises: - a pneumatic motor (36-43) with timing for screwing and unscrewing without air cut; - a nose (5) positioned on the engine and comprising: . a hexagonal socket (13) comprising a sliding ring (13 ') with hexagonal recess, . a locking sleeve (16) carrying twice two radial lights allowing a rotation of 30 ° relative to a lock (18) and terminated by a hexagon and which, after rotation, provides support under the point of the sides of the 'clip, . said latch (18) being immobilized, both in rotation relative to an external body (19) and in translation, relative to the locking sleeve (16), by means of axis screws (17-20), . a protective ring (35) in contact with the sheet metal assembly (9-10), . an outer body (19) sliding axially on the sleeve (16) under the effect of a piston (21), . said piston (21) being linked to the external body (19) by means of a stop ring (22), . a connecting sleeve (30) for securing the nose (5) to the engine (36-43), . a jack consisting of the piston (21), with its chamber (21 '), secured to the sleeve (30), . an internal guide (23) guiding the sleeve (21) in translation and in translation the locking sleeves (16), using the screw-axes (17), . a cylinder return spring (34), . a power take-off (15) linked to the motor and ensuring the rotation of a drive axis (14), . said axis (14) sliding axially in the power take-off (15) and ensuring the driving of the sleeve (13), . two stop screws (24) for stalling the engine, - a differential pneumatic device (28) comprising: . the actual differential (28) which carries a membrane (39) defining a first chamber (40), into which an engine pressure conduit (26) opens with an actuator control conduit (27) and a second chamber (41), into which opens a control pressure line (42) of the engine, possibly adjustable by a screw pointed at (42 '), . a means of connection between the differential (28) and the body (36) of a screwdriver or the body (43) of a robot head and which allows the pressure test point (42), the arrangement of said motors, nose and differential then being such that: - the nose (5) can be engaged on the clip (1) until the ring (35) is in contact with the surface of the sheet metal assembly, - when the motor turns in unscrewing, it can, initially, drive the power take-off which itself in turn drives the axis (14) and the sleeve (13) and the latter then rotating in the sleeve ( 16) by driving it in rotation through 30 ° as a result of friction in the thread (13 ') from which results the locking on the clip and in a second step, allow advancement in this socket (16) by pushing on the rod (2) of the clip while unscrewing the nut (4) and, at the end of the stroke, the abutment of the screws (24) in the bottom of the light of the power take-off (15), whence results the stalling of the motor correlatively causing the differential (28) to operate, which in turn feeds the jack (21) through the chamber (21 '), which causes the staple to be extracted, - when the motor turns in screwing, the jack is then no longer supplied and returns to its initial position under the action of the spring (34) while the friction in the threads (13 ') then causes: . firstly, unlocking the clip, . secondly, the return of all the constituent elements to their initial positions. 2. Staple remover according to claim 1, characterized in that conduits provide: - the supply (26) of the pilot motor pressure (PM), taken at the level of the motor inlet (36-43) rotating when unscrewing, - the air supply (27) to the jack, taken at the differential (28), - the supply (42) in the chamber (41) of the differential (28), of the control pressure (PT),
the function of said feeds being to allow that: - when the engine is running when unscrewed: . the control pressure (PT) is set constant in the chamber (41), . the engine pressure (PM) is less than (PT) in the engine pressure chamber (40), hence a lack of supply to the jack (21), - when the engine is stalled when unscrewed: . the control pressure (PT) is constant in the chamber (41), . the engine pressure (PM) is greater than (PT) in the engine pressure chamber (40), from which results a supply to the jack, - when the engine is running when screwing: . the control pressure (PT) is constant in the chamber (41), . the engine pressure (PM) is zero in the engine pressure chamber (40), the pressure tap being located on the engine supply when unscrewed, hence the absence of supply to the jack, - when the engine is stalled when screwing: . the control pressure (PT) is constant in the chamber (41), . the engine pressure (PM) is zero where there is no power to the cylinder. 3. _A staple remover according to claims 1 and 2, characterized in that the motor, the nose and the differential pneumatic device constitute a portable machine with revolver handle and trigger while the motor pressure and jack supply conduits are arranged in a trigger guard which also provides mechanical protection for the operator's hand. 4. A staple remover according to claims 1 and 2, characterized in that the motor, the nose, the differential pneumatic device and the conduits constitute an assembly carried by a robot arm. 5. A stapler according to claim 1, characterized in that the jack is of annular conformation around the rotating part of the nose.

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