Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K11/00—Resistance welding; Severing by resistance heating
  • B23K11/30—Features relating to electrodes
  • B23K11/3072—Devices for exchanging or removing electrodes or electrode tips

Definitions

• the present invention relates to an electrode changer capable of extracting and / or changing the electrodes of a welding gun or a welding device.
• these devices comprise two arms which are movable with respect to each other and each carrying at one of their ends a conical electrode-holder tip on which an electrode is forcibly engaged by conical fitting.
• the two electrodes which are connected to a source of electrical energy pinch the parts to be welded, so as to generate, inside the zone to be welded, a high intensity electric current locally causing a rise in temperature (by Joule effect) at a level corresponding to the welding temperature.
• the electrodes made of a material having a high electrical conductivity (such as copper), each comprise a cylindrical tubular body extended on one side by a tip terminated by a bearing face flat or spherical intended to come to bear on one of the two parts to be welded ("called active face").
• active face a bearing face flat or spherical intended to come to bear on one of the two parts to be welded
• the internal diameter of the tubular body is substantially complementary to that of the electrode holder so as to allow a conical engagement by force of the electrode on the support which ensures a joining of the two parts and which guarantees a good conduction of the electric current at the level of the junction.
• the tip has a shape of revolution (for example frustoconical) tapering from the body to the bearing face, so as to converge the current lines towards the areas to be welded and to obtain, at level of these zones, the desired current density to reach the desired welding temperature.
• a shape of revolution for example frustoconical
• these electrodes are the seat of intense wear which quickly causes deformations of the nozzle and, in particular, of the bearing face. This wear is notably due to the establishment of electric arcs which form between the electrode and the part and which end up corroding the bearing face, it being understood that the more the electrode is deteriorated, the more arcs are formed , therefore the more intense the corrosion (with risk of deterioration of the parts to be welded) and the poorer the quality of the weld.
• this phase of replacing the electrodes is particularly delicate because it involves extraction of the electrode from its support.
• the electrode adheres firmly to its support due to the initial force engagement and then to the effects of thermocompression welding exerted during welding. It is therefore often necessary to exert on the used electrode properly oriented impacts to cause it to take off. This is the reason why the automation of this replacement phase is difficult to envisage.
• patent FR No. 97 03807 a method consisting in bringing the electrode carried by an arm of the clamp into an extraction station, then in carrying out the extraction using a wedge-shaped extraction part bearing between the annular face of the electrode and an annular shoulder of the electrode holder.
• This solution provides for the application of impacts on the extraction part and, simultaneously, of a tensile force on the electrode holders.
• the object of the invention is therefore more particularly to provide a method which makes it possible to eliminate these drawbacks and to solve these problems, in a relatively simple, effective manner and which does not call into question the design and programming of automatic welding machines.
• the invention provides a method involving an electrode changing station comprising a movable transfer head, the movements of which are controlled by a processor coupled to the processor of the welding machine so as to be able to be placed in a theoretical working position identified with respect to the theoretical position of the welding electrode that is to be replaced, as determined by the welding machine, the transfer head comprising an extractor and a charger that can be alternately arranged coaxially to a transfer axis fixed relative to the head, and with a precision suitable for carrying out an electrode change.
• this method is characterized in that it comprises the following change sequence: - the displacement of the transfer head to bring it into its theoretical working position,
• the extractor may involve a rotary jaw comprising a plurality of jaws arranged radially relative to the axis of rotation of the jaw, these jaws being able to pass from a deployed position, in which they delimit a space in which can engage the electrode, in a tight position in which they come to bear on the electrode by exerting on it a centering action, then clamping so as to be able to transmit an extraction torque to it.
• the machine may also be subjected to an axial force so as to exert on the electrode a helical tearing force.
• Figure 1 is a schematic axial section of an electrode and an electrode holder secured to an arm of a welding robot clamp
• FIG. 2 is a perspective view of a welding electrode transfer apparatus according to the invention
• Figures 3 and 4 are top and side views of the apparatus shown in Figure 2;
• Figures 5 and 6 are respectively perspective and side view of the extractor of the transfer device during the engagement phase on an electrode;
• Figures 7 and 8 are figures similar to Figures 5 and 6 showing the extractor in the release position with angular displacement;
• Figure 9 is an axial section of the extractor
• FIGS. 13, 14, 15 are views of a jaw for centering and driving the electrodes, comprising a plurality of jaws, respectively in the deployed position (jaws retracted), in the intermediate position and in the clamped position (jaws resting on the electrode);
• Figures 16 and 17 are perspective views of the loader respectively in the engagement position and in the release position;
• Figures 18 and 20 are axial sections of the charger shown in Figures 16 and 17;
• Figures 19 and 21 are top views, respectively of sections 18 and 20, of the loader shown in Figures 16 and 17;
• Figures 22 and 23 are axial sections of the pivoting device of the transfer head with locking control;
• FIGS. 24a and 24b are respectively an end view and an elevation view of the pivoting mechanism;
• Figure 25 is a longitudinal view and an axial section through. reset mechanism
• FIG. 26 is a partial view of the electrode transfer apparatus, showing the location of the pivoting devices and the reset mechanisms.
• Figure 27 is a perspective view of a second welding electrode transfer apparatus according to the invention.
• Figure 28 is a side view of the apparatus shown in Figure 2;
• Figures 29 and 30 are side views of the frame of the apparatus equipped with a shaper according to two options
• Figures 31 and 32 are perspective views of the shaper alone
• Figures 33 and 34 are side views of the shaper alone;
• Figures 35 and 36 are respectively cross sections, along a vertical plane, and longitudinal, along a horizontal plane, of the shaper alone;
• Figure 37 is a perspective view of the positioner-blocker mechanism
• Figures 38a, 38b, 38c are respectively a longitudinal view, an axial section and a cross section of the positioner-blocker mechanism
• Figures 39a 39b are respectively a longitudinal view and a cross section of the positioner-blocker mechanism
• Figures 40 and 41 are perspective views of the tool holder
• Figures 42, 43, 44 and 45 are cross sections of the tool holder
• Figure 46 is a perspective view of the transfer head;
• Figure 47 is a top view of the transfer head;
• Figures 48, 49 are perspective views of the transfer head housing
• Figure 50 is a side view of the transfer head
• Figure 51 is a longitudinal section of the extractor;
• Figure 52 is a cross section of the charger;
• Figure 53 is a perspective view of the stripped transfer head of the magazine
• Figures 54a, 54b, 55a, 55b, 56a, 56b, 57a, 57b, are top and bottom views of the extraction mechanism;
• Figures 58 and 59 are cross sections of the charger;
• Figure 60 is a cross section of the loader drive mechanism
• Figure 61 is a longitudinal section of the feeder drive mechanism; and Figures 62, 63 are side views of the vertical positioning mechanism of the transfer head.
• the electrode transfer device is intended for extracting and changing the welding electrodes fitted to the welding clamp of a conventional welding robot.
• these electrodes 1 comprise a tubular body 2, slightly conical, open on the side of the largest base at the level of the radial face 3 and extended, on the other side, by a nozzle 4 having a profile of revolution stage comprising two successive chamfers 5, 6 ending in a convex shape 7.
• This electrode 1 is intended to force-engage the conical end of an electrode holder 8 of the clamp so as to obtain a hold by wedging the electrode 1 on the electrode holder 8.
• the clamp comprises two arms, one of which B1 is fixed relative to the frame of the robot, while the other B2 is mobile.
• Each of its two arms is terminated by an electrode holder on which an electrode of the above type can engage.
• the arm B2 is actuated by a mechanism so as to be able to assume a position opposite the arm Bl, known as the closing arm, in such a way that the electrodes 1 ′, 1 ", as shown in FIG. 4, are arranged coaxially one part relative to the other, at a distance from each other which may for example correspond to the thickness of the parts to be welded, and a position remote from the arm Bl, called the opening, in which the electrodes 1 ′ 1 "are separated from each other.
• This mechanism is more particularly designed so as to exert opening and closing maneuvers with relatively high forces (extraction, pinching).
• the electrode transfer device A is secured to the frame of the welding robot by means of a plate P supporting the entire mechanism of the above-mentioned electrode transfer device A, or fixed to the ground and mobile in relation to the welding robot.
• the electrode transfer device A consists of an electric reduction motor M, the output axis of which drives a first arm 9; the shaft of said gear motor M is disposed along a vertical axis Z, parallel to the vertical plane containing the above arms Bl and B2; the arm 9 is perpendicular to the shaft of the reduction gear motor M and can thus pivot around said vertical axis Z in a horizontal plane. This also applies in a position along a horizontal or inclined axis.
• pivoting assemblies are provided by two lockable pivoting mechanisms essentially comprising a cylindrical shaft 101 and a parallelepiped body 102 as shown in FIG. 22; the pivoting mechanism 10 is arranged such that its shaft 101 is secured to the arm 9 and oriented along an axis X perpendicular to the plane defined by the arm 9 and the axis Z; thus, the parallelepiped body 102 of the pivoting mechanism
• a second arm 11 in the shape of an inverted L, is integral with the body 102 of the pivoting mechanism 10, at the level of the upper end of the L; the other end of the L, the lower end, comprises a second pivoting mechanism 12; the second pivoting mechanism 12 essentially comprises a cylindrical shaft 121 and a parallelepiped body 122, as shown in FIG. 23, and is arranged in such a way that its parallelepiped body 122 is integral with the lower end of the second arm
• the shaft 121 of the pivoting mechanism 12 can pivot in the parallelepiped body 122.
• the axes X and Y compete at a point O ', O "corresponding to the point materializing the center of the barrel of the above electrodes 1', 1".
• the shaft 121 of the pivoting mechanism 12, pivoting in the tubular body 122, is integral with a flange 13, C-shaped; the above-mentioned shaft 121 is perpendicular to the amount of the C representing the above-mentioned flange 13.
• a cylindrical shaft 14 is made integral with the flange 13, passing right through it perpendicularly to the two wings of its C shape, defining an axis ⁇ of rotation; thus, the shaft 14, parallel to the upright of the C representing the above-mentioned flange 13, is perpendicular to the Y axis and can pivot in a plane normal to said Y axis.
• the transfer head T has a shape close to a V, and is articulated around the cylindrical shaft 14, located perpendicular to the plane defined by said V shape, at the base of said V. At each end of said shape in V are located respectively the extractor and the welding electrode charger.
• the transfer head T has four degrees of freedom defined by the four axes of rotation Z, X, Y, ⁇ ; the two axes Z and ⁇ make it possible to bring either the extractor or the charger of said head in a coaxial position relative to the axis of the electrode 1 "; the axes X and Y define an approach sphere relative to the actual position of said 1 "electrode.
• An assembly comprising the elements 10 ′, 11 ′, 12 ′, 13 ′, 14 ′ and the corresponding axes X ′, Y ′, ⁇ ′, arranged head to tail relative to the assembly constituted by the elements 10, 11, 12, 13, 14 and the corresponding axes X, Y, ⁇ , secured to the arm 9, with an opposite end to that secured to the outlet axis of the gear motor M, constitutes the support for the transfer head T '.
• the transfer head T ' has four degrees of freedom defined by the four axes of rotation Z, X', Y ', ⁇ '; the two axes Z and ⁇ 'make it possible to bring either the extractor or the charger of said head in a coaxial position relative to the axis of the electrode l'; the axes X 'and Y' define an approach sphere relative to the real position of said electrode 1 '.
• the transfer head T comprises a body 15, V-shaped, articulated around the cylindrical shaft 14, which is located at the base of said V; the aforesaid body 15 supports, at the two ends of its V-shape, an extractor E whose main axis ⁇ l, in the rest position of said extractor, is collinear with the axis of rotation ⁇ of the transfer head T and a loader C whose main axis ⁇ 3 is also collinear with the axis of rotation ⁇ of the transfer head T.
• the extractor E which will be described in more detail later, essentially consists of a housing 16 supporting an extraction device 17 and a reduction gear motor 18; the extraction device 17 of the extractor E is arranged coaxially with the main axis ⁇ l of said extractor; the gear motor 18 is arranged coaxially to an axis ⁇ 2; the two axes ⁇ l, ⁇ 2 are collinear with the axis of rotation ⁇ of the transfer head T, said extractor E being in the rest position.
• the housing 16 of the extractor E is integral with the body 15 of the transfer head T by means of a cylindrical shaft 19, arranged in the end of the corresponding branch of the V shape of said head, so that the axis ⁇ 0 of the cylindrical axis 19 is perpendicular to the plane defined by the axes ⁇ , ⁇ l; thus, the housing 16 can slightly pivot around the cylindrical shaft 19, between a rest position corresponding to the collinearity of the two axes ⁇ , ⁇ l, and a slightly oblique position, called extraction.
• the charger C which will be described in more detail later, essentially consists of a housing 20 supporting a barrel 21 and of a geared motor drive 22; the barrel 21 of the charger C is arranged coaxially with the main axis ⁇ 3 of said charger; the gear motor 22 is arranged coaxially with an axis ⁇ 4; the two axes ⁇ 3, ⁇ 4 are collinear with the axis of rotation ⁇ of the transfer head T.
• the housing 20 of the charger C is integral with the body 15 of the transfer head T at the end of the corresponding branch of the V shape of said head.
• the transfer head T comprises a lifting device L, pivotally mounted around the shaft 14 of said transfer head T;
• the lifting device L comprises a plate 23, pivotally mounted on the shaft 14 at its lower end, beyond the flange 13, so that it can pivot around the cylindrical shaft 14 and not translate vertically along said cylindrical shaft 14 by means of shoulders not shown.
• Said plate 23 comprises a gear motor 24 actuating a bevel gear 25, which actuates a helical screw 26 whose axis is collinear with the axis ⁇ of the transfer head T; said helical screw 26 bears on the lower surface of the body 15 of the transfer head T and its upward and downward movement caused by the gear motor 24, makes it possible to move the assembly of the transfer head along the axis ⁇ defined by the cylindrical shaft 14.
• the downward movement of the transfer head T allows the approach of the extractor E around the electrode; the upward movement of said transfer head T, preceded by the clamping operation of the electrode described in more detail later, allows the extraction of the electrode.
• the downward movement of the transfer head T allows the charger C to approach the level of the electrode support, allowing the electrode to be changed; the upward movement of said transfer head T allows the magazine C to be released.
• the change operation electrode will be preceded by a rotational movement of said transfer head around its shaft 14, so as to bring the charger C in the position identical to that previously occupied by the extractor E.
• the extractor E consists of a housing 16 supporting an extraction device 17 and a reduction gear motor 18; said housing 16 is integral with the transfer head T via the cylindrical shaft 19; the extraction device 17 of the extractor E is arranged coaxially with the main axis ⁇ l of said extractor; the gear motor 18 is arranged coaxially with the axis ⁇ 2; the two axes ⁇ l, ⁇ 2 are perpendicular to the upper external surface of the housing 16; the gear motor 18 is disposed below the housing 16, integral with said housing, and its drive shaft comprises in the upper part a pinion (not shown), which pinion drives a toothed crown 29 disposed in the middle zone of said housing 16; said toothed ring 29 drives a shaft 30, crossing vertically right through said housing 17 and its axis ⁇ l ', collinear with the two axes ⁇ l, ⁇ 2, is located in the plane containing the axes ⁇ l, ⁇ , closer to ⁇ l axis than the
• the extraction device 17 consists of a crown 32 comprising a plurality of teeth on its external periphery and a plurality of teeth on its internal periphery, the plurality of external teeth being in drive relation with said second ring gear 31; a plurality of jaws, five of which are shown in FIGS.
• jaws 33 a to 33 e pivoting about their respective axes 33 a 'to 33 e' each have a part in an arc of a circle concentric with their axis of rotation and a gripping part; said part in an arc, with an opening of between 100 ° and 180 °, comprises a plurality of teeth meshing with the opposite part of the plurality of internal teeth of said crown 32; the grip part has a slightly rounded tip.
• the transfer head T having its four degrees of freedom described above, will be driven by a self-centering movement of the extraction device 17 relative to the electrode during the rotation in a clockwise direction.
• said crown 32 gradually making the axis ⁇ l coincide with the main axis of the electrode, as shown in FIGS. 13, 14, 15.
• the extractor E comprises a drum 34, integral with the cylindrical shaft 30, in the middle zone of said cylindrical shaft 30, below the ring gear 29; the aforesaid drum 34 comprises on its periphery a plurality of ferromagnetic pads positioned opposite a plurality of electromagnetic angular position sensors 35a to 35c, integral with the housing 16, and arranged radially on said housing 16.
• the extractor E further comprises a disc 36, integral with the cylindrical shaft 30, below said drum 34, close to the underside of the housing 16; the aforesaid disc 36 comprises, in an angular sector between 90 ° and 130 °, a cylindrical zone surrounded on one side by a slight bell-shaped protuberance and on the opposite side, a hook oriented towards said cylindrical zone of the disc 36.
• the extractor E further comprises a piston 38, disposed radially to the aforesaid disc 36, along an axis contained in the plane defined by the axes ⁇ , ⁇ l, ⁇ l ', facing the peripheral surface of the aforementioned disc 34, passing through the housing 16 in the opposite direction to that of the extraction device 17; said piston 38 comprises at its internal end, opposite the disc 36, a pin 37 whose axis is collinear with the axis ⁇ l ', and at its external end, a pin 39, whose axis is orthogonal to that of the pin 37; thus, the aforesaid disc 36, driven, clockwise, by the reduction motor 18, by means of its drive pinion, the toothed ring 29 and the cylindrical shaft 30, is present:
• the so-called “locking” position makes it possible to keep the jaws retracted in the deployed position of the extraction device 17, in order to avoid possible contact of said jaws with the electrode during the positioning of the extractor E around the electrode; the so-called “progressive clamping” position of said jaws makes it possible to pass from the deployed position to the clamped position.
• an index i (FIG. 9) urged by a friction mechanism firstly ensures that the ring 33 for supporting the jaws is prevented from rotating.
• the index i disappears to release the crown 33 which can then rotate in synchronism with the crown 32 with, however, a tightening hold due to the torque generated by the friction forces ; the third step called “tilting” allows said housing 16 to tilt slightly around the cylindrical shaft 19, the pin 39 being received in a recess, not shown, located in the body 15 of the transfer head T.
• the charger C consists of a housing 20 supporting a barrel 21 and a reduction gear motor 22; the barrel 21 of the charger C is arranged coaxially with the main axis ⁇ 3 of said charger and comprises a plurality of lids intended to receive the electrodes; the gear motor 22 is arranged coaxially with the axis ⁇ 4; the two axes ⁇ 3, ⁇ 4 are collinear with the axis of rotation ⁇ of the transfer head T.
• the housing 20 of the charger C is secured to the body 15 of the transfer head T via a tenon / mortise connection at the end of the corresponding branch of the V-shape of said head.
• the gear motor 22 is disposed below the housing 20, integral with said housing, and its drive axis comprises in the upper part a disc 40 disposed between the upper wall of the housing 20 and the barrel 21.
• the barrel 21 is pivotally mounted around a shaft 41, which is integral with the housing 20 and is coaxial with the axis ⁇ 3; a disc 42, of outside diameter less than the outside diameter of the barrel, is pivotally mounted around the shaft 41 and is arranged below said barrel 21; the disc 42 is made integral with the barrel 21 by two threaded screws 43, arranged axially.
• the disc 42 consists of a plurality of branches of a number equivalent to that of the plurality of lids situated on the barrel and intended to receive the electrodes; each branch, of equal length, widens from the center to the edge of the disc and forms a double plurality of points on the outer periphery of said disc; each branch is separated from the adjacent branches by a slot of equivalent shape and having two parallel edges; the end of each branch has a circular notch connecting the two points of the periphery of the disc 42; the set of branches represents a Maltese cross, the number of branches of which is equivalent to the number of electrodes placed on said barrel 21.
• the above-mentioned disc 40 has on its upper face, facing the above-mentioned disc 42, a on the one hand, a first tenon of cross section in a half-moon and, on the other hand, diametrically opposite, a tenon of circular section; the first tenon is intended to be housed in the notches of the branches of the disc 42; the second stud is intended to be housed in the slots separating said branches from the disc 42; thus, during a 360 ° rotation of the disc 40 around the axis ⁇ 4, the first tenon then the second tenon drive the disc 42 in rotation around the axis ⁇ 3 by a sector of angle equivalent to that of 'a branch and a slot of the aforesaid disc 42.
• the angular displacement of the disc 42 is transmitted to the barrel 21 and thus makes it possible to position the electrode opposite the corresponding housing of the electrode holder.
• each electrode comprises a tubular body 2 extended by a nozzle 4 having a stage revolution profile which comprises a chamfer 5 for connection between said tubular body 2 and said nozzle 4; an O-ring 46 is arranged around the electrode on said tubular body 2, near said chamfer 5, and makes it possible to maintain the electrode in a vertical position in the cover of barrel 21; the final positioning of the electrode in the corresponding housing of the electrode holder, that is to say the fitting, is carried out by a closing movement of the welding device.
• the transfer head T comprises an elevation device L, pivotally mounted around the shaft 14 of said transfer head T.
• the pivoting mechanisms 10 and 12 comprise a cylindrical shaft, respectively 101 and 121, which can slide and pivot in the bore of a body of parallelepiped shape, respectively 102 and 122; the two mechanisms being of equivalent structure, we will limit our to the example shown in FIGS. 22 and 24.
• the cylindrical shaft 101 passes right through the parallelepipedic body 102 and is supported in the above body by two ball bushings 103 and 104, respectively disposed at the end of the said body near the end of the cylindrical shaft 101 integral with the arm 9, and close to a blocking device B.
• the locking device comprises a support cup 105, a locking washer 106, a support washer
• the body 102 comprises, on the side of the blocking device, an annular recess arranged coaxially with the axis X of said body; the above-mentioned recess contains the support cup 105, the locking washer 106 and the support washer 107.
• the . support cup 105 of inverted L-shaped section, secured by its external face to the body 102, bears on the internal face of the recess and is freely traversed by the cylindrical shaft 101.
• the locking washer 106 in the form of a cup having a concavity facing the adjacent end of the body 102, is also crossed freely by the cylindrical shaft 101; its external face, of cylindrical shape, coaxial with the axis X, bears freely on the internal surface of the support cup 105.
• the support washer 107 of rectangular section, is also freely traversed by the cylindrical axis 101; its external face, of cylindrical shape, coaxial with the axis X, bears freely on the internal surface of the recess of the body 102, at a distance from the support cup 105 greater than the displacement of the locking screw 108.
• the locking screw 108 comprises a sleeve, externally threaded and a cylindrical shoulder, coaxial with the axis X, allowing the gripping of the locking screw; the cylindrical internal surface of the threaded sleeve bears freely on the shaft 101; the threaded cylindrical outer surface is screwed into the end flange 109 of the body 102; the end of the threaded sleeve, opposite the gripping shoulder, bears on the support washer 107.
• the end flange 109 of cross section equivalent to the body 102, is integral with the aforesaid body by a fixing means not shown, and comprises, coaxially with the axis X, a threaded surface, complementary to the threaded sleeve of the locking screw 108.
• a rotational movement of the locking screw 108 causes the translation of the aforesaid screw taking support on the support washer 107 which, in turn, takes support on the locking washer 106, causing its radial deformation; this radial deformation has the effect of reducing the inside diameter and increasing the outside diameter of the said locking washer 106, causing the shaft 101 and the support cup 105 to join together and, consequently, the joining of the shaft 101 and the body 102.
• the counterclockwise reverse movement of the locking screw 108 causes the shaft 101 and the body 102 to become detached.
• a disc 110 is integral with the end of the shaft 101 opposite to that concerned by the locking device B; the aforesaid disc 110 comprises on an area of its peripheral surface an arm, of the same thickness as the cylindrical part of the disc 110, arranged radially and comprising a cylindrical orifice, crossing the thickness of the arm and whose axis is parallel to the body X axis 102; this orifice is the housing of a stud secured to a reset mechanism which will be described below.
• the arm of the disc 110 integral with the shaft 101, pivots about the axis X and translates along said axis X, as a function of the relative movement between the shaft 101 and the body 102 of the pivoting mechanism with locking 10. It is the same for the arm of the disc 130, integral with the shaft 121 of the pivoting mechanism with blocking 12.
• a reset mechanism RZ which will be described below, is reproduced in four copies, at a rate two reset mechanisms by pivoting device with lock; in fact, each pivoting device has, as indicated above, two degrees of freedom, namely: a rotational movement around the axis of the body of the pivoting device and a translational movement along the above-mentioned axis; thus, each degree of freedom is associated with a reset mechanism.
• the reset mechanism RZ referenced 200, comprises a tubular part comprising two cylindrical sleeves of the same diameter 201 and 202, integral with one another by a third sleeve 203, of short length, of the same outside diameter and having a smaller inside diameter than that of the above sleeves
• the assembly is coaxial with a main axis ⁇ 5; two cylindrical ends 204 and 205 are respectively fixed to the sleeves 201 and
• each of the aforesaid ends 204 and 205 consists of a cylindrical sleeve whose internal surface is integral with the external surface of said cylindrical sleeves 201 and 202, and of a wall normal to the main axis ⁇ 5; the end piece 204 has, at its wall normal to the main axis ⁇ 5, a cylindrical orifice with a diameter less than the inside diameter of said central sleeve 203; a cylindrical shaft 206, sliding freely in the orifice of the wall of the end piece 204, penetrates the assembly consisting of the three sleeves 201, 202, 203, and comprises, near the internal end, a shoulder of equivalent length the length of the sleeve 203, and sliding freely in the inner cylindrical part of said sleeve 203; on either side of the shoulder of the cylindrical shaft 206, two other cylindrical sleeves 207, 208 with a length close to a third of that of the sleeves 201, 202, slide freely on the cylindrical shaft 206 and on the
• a displacement of the cylindrical shaft 206, caused by an external force, along the axis ⁇ 5, causes additional compression of one of the two helical springs concerned; the external force ceasing, the cylindrical shaft returns to its initial position, its shoulder being in facing with the sleeve 203.
• the pivoting devices with blocking 10, 12 each comprise two reset mechanisms corresponding to the two degrees of freedom that said pivoting devices with blocking 10, 12.
• the second arm 11 in the shape of an inverted L, comprises at the upper end of the L, the pivoting device
• the cylindrical shaft 101 of the pivoting device 10 is coaxial with the axis X and integral with the first arm 9;
• the cylindrical shaft 121 of the pivoting device 12 is coaxial with the axis Y and integral with the flange 13 of the transfer head T.
• the arm of the disc 110, integral with the shaft 101 of the pivoting device 10 comprises two tenons, one of which is coaxial with the shaft 101 and the other of which is perpendicular to said shaft 101; likewise, the arm 210, integral with the shaft
• the 121 of the pivoting device 12 comprises two tenons, one of which is coaxial with the shaft 121 and the other of which is perpendicular to said shaft 121.
• the pivoting device 10 comprises two reset mechanisms 200a, 200b; similarly, the pivoting device 12 comprises two reset mechanisms 200c, 200d.
• the flange 213a of the reset mechanism 200a is integral with the first tenon of the arm of the disc 110 of the pivoting device 10.
• the flange 214a of the reset mechanism 200a is secured to the vertical upright of the inverted L of the arm 11.
• the flange 213b of the reset mechanism 200b is secured to the second tenon of the arm of the disc 110 of the pivoting device 10.
• the flange 214b of the reset mechanism 200b is integral with the body 102 of the pivoting device 10.
• the flange 213c of the reset mechanism 200c is integral with the first tenon of the arm of the disc 130 of the pivoting device 12.
• the flange 214c of the reset mechanism 200c is integral with the horizontal upright of the inverted L of the arm 11.
• the flange 213d of the reset mechanism 200d is secured to the second tenon of the arm of the disc 130 of the pivoting device 12.
• the flange 214d of the reset mechanism 200d is secured to the body 122 of the pivoting device 12.
• the electrode change sequence is as follows:
• the electrode transfer device according to the invention is also intended for extracting and changing the welding electrodes fitted to the welding clamp of a conventional welding robot.
• the clamp comprises two arms, one of which B1 is fixed relative to the frame of the robot, while the other B2 is mobile.
• Each of its two arms is terminated by an electrode holder on which an electrode of the abovementioned type can be engaged, that is to say one secured to the electrode holder of arm B 1, and one "secured to the electrode holder of arm B2.
• the electrode transfer device A is not secured to the frame of the welding robot; it rests on the ground, in the immediate vicinity of the welding robot. Furthermore, in the same way as the first example, the electrode transfer device which will be described, allows the two electrodes associated with the electrode holders of the two arms of the welding gun to be changed, by tilting the second arm after the replacement of the electrode of the electrode holder of the first arm.
• the electrode transfer apparatus A comprises a column I of rectangular section, the main axis Z of which is vertical and parallel to the vertical plane containing the above arms Bl and B2.
• column I supports, opposite the welding robot, a tank BA for receiving used electrodes, and on the side opposite to said welding robot, an electronic unit BE containing the various command and control members of the welding machine. transfer of electrodes A.
• this second example only has a single transfer head T making it possible to extract and replace the used welding electrodes on the two aforementioned arms Bl, B2, according to a process which will be described later.
• the transfer head T comprises an extractor E and a charger C, substantially identical to those described according to the first example; the said transfer head T is integral with a tool holder PO, allowing a displacement of the transfer head T along two orthogonal axes ⁇ l and ⁇ 2, respectively the axis of translation, perpendicular to the plane defined by the two arms Bl, B2, and the axis of engagement / disengagement, perpendicular to the axis ⁇ l, and contained in a plane parallel to the plane defined by the two arms Bl, B2.
• the PO tool holder is integral with the CO conformator, allowing the PO tool holder to:
• the CO shaper includes a central shaft CO whose axis is the above axis ⁇ 3; said central shaft COi comprises at one of its ends a flange C0 2 , in the form of a disc, making it possible to. secure the above-mentioned tool holder PO to the central shaft COi; moreover, it is pivotally mounted and slidable in a parallelepipedic body C0 3 , by means of two bearings or bearings C0 4 , C0 5 , arranged at each end of said body C0 3 ; thus, the aforesaid central shaft COi can pivot around its axis ⁇ 3 and move along said axis ⁇ 3.
• the parallelepiped body C0 3 comprises two ribs of the same thickness, and of width close to that of said body C0 3 , located symmetrically on either side of the body C0 3 , in a plane perpendicular to the axis ⁇ 3, which plane is located approximately the first third of the length of the body C0 3 , close to the flange C0 2 .
• each of said ribs are mounted two shafts C0 6 , C0 7 , whose respective axes are mutually parallel and perpendicular to the axis ⁇ 3; the aforesaid shafts C0 6 , C0 7 are mounted to pivot and slide in their respective ribs by means of bearings, respectively C0 61 , C0 62 , C0 71 , C0 72 ; moreover, the shafts C0 6 , C0 7 emerge on either side of the width of their respective ribs.
• a frame C0 8 of rectangular shape and thickness close to that of the above-mentioned ribs, surrounds the above-mentioned body C0 3 at the level of the said ribs and is integral with the two shafts C0 6 , C0 7 , at the level of their emerging parts, while leaving sufficient play; thus, this clearance allows the assembly consisting of the body C0 3 and the central shaft COi to move in the frame COg along the above axis ⁇ 5.
• the above-mentioned shafts C0 6 , C0 7 emerge in their turn from the frame C0 8 on either side of said frame COg so as to be able to slide in two curved grooves situated in two walls C0 9 , CO 10 ; the above walls C0 9 , CO ⁇ 0 are arranged in a vertical plane, on either side of said frame C0 8 , and integral with a horizontal sole CO n , itself integral with the above-mentioned column I, at its the top part.
• the two ribs, located in the COg frame each form an arc, the center of which is at point O corresponding to the point materializing the center of the barrel of the above electrodes 1 ', 1 ".
• the axis ⁇ 3 of the central shaft COi can pivot around the point O in a vertical plane, the axis ⁇ 5 of translation of said axis ⁇ 3 of the central shaft COi describing a cylindrical surface whose axis is horizontal and passes by point O.
• the central shaft COi can pivot around its axis ⁇ 3, translate along said axis ⁇ 3 and translate perpendicular to said axis ⁇ 3 in a plane passing through the aforesaid axis ⁇ 4, which plane can pivot around said axis ⁇ 4, the above axis ⁇ 4 passing through the above point O.
• the frame C0 8 comprises, at the lower level, a rib extending downward, which is crossed by a shaft C0 12 whose axis ⁇ 6 is parallel to the axes of the above trees C0 6 , C0 7 ; this CO ⁇ 2 shaft, rotatably mounted in the above rib of the frame C0 8 , emerges on either side of said rib; each of the two ends of the shaft CO 2 is pivotally mounted in a flange CO 3 , H-shaped; said ends of the shaft CO ⁇ 2 pass through the two upper arms of the H and are held by two screws secured to the shaft CO ⁇ 2 .
• the other two lower arms of the H are crossed by a shaft C0 14 whose axis ⁇ 7 is parallel to the axis ⁇ 6; the aforesaid shaft CO] 4 is pivotally mounted in an arm C0 15 ; the ends of the shaft C0 14 pass through the two lower arms of the H and are held by two screws secured to the shaft C0 14 .
• the aforesaid arm CO ⁇ 5 articulated at one of its ends by means of the shaft CO ⁇ , is also articulated at the other end by means of a shaft CO ⁇ 6 whose axis ⁇ 8 is parallel to the axis ⁇ 7; the above-mentioned shaft C0 16 is pivotally mounted in the two branches of a C-shaped CO ⁇ base, integral with the sole COn; the ends of the shaft C0 16 cross the two branches of the C and are held by two screws integral with the shaft CO ⁇ 6 .
• the flange CO ⁇ 3 in the form of H, associated with the two shafts CO ⁇ 2 , CO]
• the arm CO 15 associated with the two shafts CO ⁇ 4 , CO ⁇ 6 , the base C0 17 , secured to the sole CO] ls allow the CO g frame to be held laterally.
• the crew surrounding the central shaft COi consisting of the co ⁇ s C0 3 , the frame CO s , the flange CO ⁇ 3 , the arm CO ⁇ 5 , and the shafts C0 6 , C0 7 , CO ⁇ 2 , CO ⁇ 4 , represents a certain mass, to which must be added the representative masses of the tool holder PO and of the transfer head T, the center of gravity of the assembly lying in a plane close to that defined by the sole CO ⁇ .
• a first connection system between the frame C0 8 and the column I or the associated sole COn will exert an almost vertical force from bottom to top, the amplitude of which is close to the mass of the above-mentioned assembly.
• a second connection system between the COg frame and the walls C0 9 , CO ⁇ 0 will exert two opposing forces.
• the first system as shown in Figures 29, 30, can take two forms:
• the cable being secured, at one of its ends, to a guided sliding arm, itself secured to the frame C0 8 , and at the other end of the above against weight,
• Figure 30 a second option ( Figure 30) comprising a gas spring secured, at one of its ends, to a fixing flange itself secured to the column I, and at the other end of a fixing flange itself secured to the frame C0 8 .
• the second system as shown in Figures 31, 33, 34, comprises two air springs CO ⁇ 8 , CO 19 , exerting an almost vertical force, one from top to bottom and the other from bottom to top in bearing, on the one hand, on the walls C0 9 , CO 10 and, on the other hand, on the frame C0 8 .
• the gas spring C0 18 is integral, at its upper articulation with the frame C0 8 , and at its lower articulation with the wall CO 9 .
• the gas spring CO 19 is integral, at its lower articulation of the frame C0 8 , and at its upper articulation of the wall
• the central shaft COi associated with its mobile equipment previously described, can pivot around its axis ⁇ 3, translate along said axis ⁇ 3 and translate pe ⁇ endicululaire to said axis ⁇ 3 in a plane passing through the aforesaid axis ⁇ 4, which plane can pivot around said axis ⁇ 4, the aforesaid axis ⁇ 4 passing through the above point O.
• four degrees of freedom are associated with said central shaft COi.
• the extractor E is positioned precisely around the used electrode and consequently defines the positioning of the transfer head T; the corresponding position of the transfer head T must be kept to allow precise positioning of the charger C, when changing a new electrode.
• the positioner-blocker mechanism PB comprises a tubular part comprising two cylindrical sleeves of the same diameter 301 and 302, integral with one another by a third sleeve 303, of short length, coming to cover one of the ends of each of the sleeves 301, 302, and having a smaller internal diameter than that of the sleeves 301 and 302; the assembly is coaxial with a main axis ⁇ 0; two cylindrical ends 304 and 305 are respectively secured to sleeves 301 and 302 at their free end; each of the aforesaid ends 304 and 305 consists of a cylindrical sleeve whose internal surface is integral with the external surface of said cylindrical sleeves 301 and 302, and of a wall normal to the main axis ⁇ 0; the end piece 304 comprises at its wall normal to the main axis
• a housing of parallelepiped shape 314 is crossed by the free end of the cylindrical shaft 306; at the level of the cavity of said casing 314, surrounding the cylindrical shaft 306, two plates 315, 316, of rectangular shape, are arranged substantially pe ⁇ endicular to the shaft 306 which passes through them; these two plates 315, 316, are pierced with a cylindrical orifice whose internal diameter is slightly greater than the external diameter of the shaft 306; said plates 315, 316 are arranged one opposite the other and each comprise, one facing the other, a blind hole for accommodating a compression spring 317, thus tending to separate the two plates 315 , 316 from each other.
• two pins 318, 319, respectively associated with the plates 315, 316, whose main axis is pe ⁇ endicular to the axis ⁇ 0, are integral with the casing 314; thus, the two plates 315, 316 are kept pivoting one opposite the other and, being subjected to a spacing due to the presence of the compression spring 317, will make it possible to block the shaft 306 relative to the casing 314 .
• a metal cable under sheath 320 is secured at one of its ends to the plate 315; disposed parallel to the axis ⁇ 0, it passes through a metal tube 321, itself integral with the end piece 304 and pressing, at one of its ends, on the plate 316.
• a tensile force applied to the cable 320, relative to the casing 314 allows the plate 315 to be brought closer to the plate 316, so as to arrange them substantially parallel, which, consequently, frees the shaft 306 in translation.
• the positioner-blocker mechanism PB comprises a stirrup 322, U-shaped, the axis of articulation ⁇ O ', crossing the two branches of the U, is pe ⁇ endicular to the axis ⁇ O; this stirrup 322 is associated with the positioner-blocker mechanism PB, at the casing 314, by means of two shoulder screws 323, 324, integral with the casing 314, allowing said stirrup 322 to pivot freely around the axis ⁇ O '; a third shouldered screw 325, secured to the base of the U, is arranged so that its axis ⁇ O "is pe ⁇ endicular to the plane defined by the axes ⁇ O and ⁇ O '.
• All of the elements referenced 322, 323, 324, 325 constitute the second attachment point of the positioner-blocker mechanism PB.
• Four positioner-blocker mechanisms PB1, PB2, PB3, PB4 are associated with the four degrees of freedom of the central shaft COi; more precisely, the fourth mechanism PB4 only includes the blocking part.
• the central shaft COi comprises at its free end, opposite to that associated with the circular flange COi, a finger CO 20 , secured at one of its ends, to the central shaft COi, and arranged pe ⁇ endicular to the axis ⁇ 3; at the other free end, the CO 20 finger comprises a pin whose axis is parallel to the aforesaid CO 20 finger; this pin determines the fixing point of two positioner-blocker mechanisms PB1, PB2, by means of their respective flange 313.
• the positioner-blocker mechanism PB1 is arranged so that its main axis ⁇ 0 is pe ⁇ endicular to the axis ⁇ 3 of the central shaft COj; the upper fixing point, as indicated above, is integral with the pin 20 CO pin; the lower fixing point, at its shoulder screw 325, is located on a base C0 2 ⁇ , itself secured to the co ⁇ s C0 3 ; thus, the PB1 positioner-blocker mechanism positions and blocks the central shaft COi in rotation around its axis ⁇ 3, that is to say according to its first degree of freedom.
• the positioner-blocker mechanism PB2 is arranged so that its main axis ⁇ O is parallel to the axis ⁇ 3 of the central shaft COi; the upper fixing point, as indicated above, is integral with the pin 20 CO pin; the lower fixing point, at the level of its shoulder screw 325, is integral with the co ⁇ s C0 3 ; thus, the positioner-blocker mechanism PB2 positions and blocks the central shaft COi in translation along its axis ⁇ 3, that is to say according to its second degree of freedom.
• the positioner-blocker mechanism PB3 is arranged so that its main axis ⁇ O is pe ⁇ endicular to the respective main axes of the positioner-blocker mechanisms PB1, PB2; it is therefore pe ⁇ endicular to the axis ⁇ 3 of the central shaft COi; the upper fixing point, at its flange 313 is integral with the COg frame; the lower fixing point, at the level of its shoulder screw 325, is integral with the co ⁇ s C0 3 ; thus, the positioner-blocker mechanism PB3 positions and blocks the central shaft COi in translation along the axis ⁇ 5, that is to say according to its third degree of freedom.
• the PB4 positioner-blocker mechanism only includes the blocker part; it is arranged so that its main axis ⁇ 0 is substantially parallel to the main axis ⁇ 0 of the positioner-blocker mechanism PB 1; the upper fixing point, at its flange 313 is integral with a spacer C0 2 connecting the two walls C0 9 , CO ⁇ 0 , at their upper part, parallel to the sole COn; the lower fixing point, at the level of its shoulder screw 325, is integral with the frame C0 8 ; thus, the positioner-blocker mechanism PB4 blocks the central shaft COi in rotation around the point O, corresponding to the point materializing the center of the barrel of the electrode, that is to say according to its fourth degree of freedom. Furthermore, the above blocker part is associated with the two gas springs C0 18 , CO ⁇ 9 , previously described, in order to constitute the positioner-blocker mechanism PB4.
• each positioner-blocker mechanism PB1, PB2, PB3, PB4 comprises a metallic cable under sheath making it possible to unlock the corresponding shaft by pulling on said cable. These pulls will be performed automatically at the transfer head T, and will be described later.
• the above transfer head is integral with the central shaft C ⁇ ! through the PO tool holder; it essentially consists of a so-called motorized "XY" table allowing the transfer head to move along the two orthogonal axes referenced ⁇ l, ⁇ 2.
• the tool holder PO as shown in FIGS. 40, 41, essentially comprises two orthogonal C-shaped cradles; a first cradle, integral with the central shaft COi belonging to the CO shaper, whose main axis ⁇ 2 is located in a plane containing the axis ⁇ 3 of the central shaft CO l5 which first cradle supports and drives a second cradle whose l main axis ⁇ l is pe ⁇ endicular to the plane defined by the above axes
• the above second cradle supports and drives the transfer head T.
• the central shaft COi can pivot around its axis ⁇ 3, the axis ⁇ 2 of the first cradle may not be vertical and the axis ⁇ l of the second cradle may not be horizontal.
• each of the aforementioned cradles in the form of a C, comprises a driving mother screw whose axis corresponds to the main axis of said cradle, and two guide columns, of circular section, whose axes are parallel to said main axis of the cradle.
• the lead screw is kept pivoting in the cradle at the level of the two branches of the C; the two guide columns are secured to the cradle also at the level of the two branches of the C.
• Each of the mother screws is secured to one of its ends of a pulley, which is driven, by means of a belt, by an electric motor, which is secured to the cradle by means of a plate.
• the lead screw is in connection with an angular position sensor also integral with the corresponding cradle.
• Each of the mother screws drives a threaded nut in shape correspondence with the threads of the mother screw; a first nut of the first cradle drives the second cradle; a second nut of the second cradle drives the transfer head T.
• the drive of the second cradle or of the transfer head by the corresponding nut comprises a mechanism making it possible to obtain a certain elasticity, on either side of a equilibrium position, along the main axis of the corresponding cradle. Said mechanism makes it possible to position the mobile element of the cradle in abutment on either side of the movement of said mobile element.
• the first cradle P0 20 o in the form of C, secured to the central shaft COi of the conformator CO by means of the circular flange C0 2 , comprises: - a screw mother PO 20 ⁇ , the axis of which is collinear with the main axis ⁇ 2 of the cradle P0 20 o, pivotally mounted at the level of the two branches of the C, - two guide columns P0 2 o, PO 203 , whose axes respectively ⁇ 2 ', ⁇ 2 "are parallel to the main axis ⁇ 2, mounted integral with the two branches of the C, - a toothed pulley PO 20 , mounted integral with the mother screw PO 20 ⁇ , at the upper end of said mother screw PO 20 ⁇ , a PO 20 electric motor, the main axis ⁇ 2 '"of which is parallel to the axis ⁇ 2, mounted integral with a plate PO 208 , which is integral with the upper branch of the C
• a second toothed pulley PO 205 secured to the shaft of the electric motor PO 207 , driving the pulley PO 204 by means of a toothed belt PO 206 ,
• An angular position sensor PO 209 the shaft of which is driven by the lead screw PO 20 ⁇ at its lower end, the co ⁇ s of said sensor PO 20 ⁇ being integral with the lower branch of the C of the cradle P0 20 o.
• the second cradle P0 10 o driven by the lead screw PO 20 ⁇ and guided by the guide columns P0 2 o 2 , P0 2 o 3 of the first cradle, comprises:
• a notched pulley PO ⁇ 04 mounted integral with the mother screw POioi, at a first end of said mother screw POioi, - an electric motor PO 10 , whose main axis ⁇ l '"is parallel to the axis ⁇ l , mounted integral with a plate PO ⁇ 08 , which is integral with the corresponding branch of the C of the POioo cradle,
• a second toothed pulley PO ⁇ 05 secured to the shaft of the electric motor PO ⁇ 0 , driving the pulley PO 104 by means of a toothed belt PO ⁇ 06 ,
• the first cradle is shown in cross section along the plane defined by the axes ⁇ 2, ⁇ 3; in the example shown in Figure 43, the first cradle is shown in cross section along the plane containing the axis ⁇ 2 and pe ⁇ endicular to the axis ⁇ 3.
• the PO 20 ⁇ lead screw is pivotally mounted:
• the lead screw PO 20 ⁇ drives a threaded nut P0 2 ⁇ , of partially circular section, which nut P0 2 ⁇ 4 slides freely in a cylindrical cavity P0 2 i 5 , concentric with the axis ⁇ 2; the cylindrical cavity P0 2 ⁇ 5 passes right through the POioo cradle at the level of the wall connecting the two branches of the C.
• the aforementioned nut P0 i4 is not directly integral with the POioo cradle, as indicated above, a mechanism makes it possible to associate said nut P0 2 ⁇ with a degree of freedom along the axis ⁇ 2. Indeed, the nut P0 2 ⁇ 4 is positioned between two rings P0 2 ⁇ 6 , P0 2 ⁇ 7 , of circular section, of length close to that of the nut P0 2 ⁇ , and sliding freely in the cylindrical cavity P0 2 to 5 .
• the above cylindrical cavity P0 2 ⁇ 5 is limited, at each of its ends, by two flanges P0 2 ⁇ 8 , P0 2 ⁇ 9 , integral with the cradle POioo, respectively at the upper level and at the lower level of said cradle POioo-
• the spaces in the cylindrical cavity P0 2 ⁇ 5 defined, on the one hand, by the ring P0 2i6 and the flange P0 2 ⁇ 8 and, on the other hand, by the ring P0 2 ⁇ 7 and the flange P0 219 respectively contain the springs PO 220 and P0 221 , which springs P0 22 o and P0 22 ⁇ are mounted in compression.
• the admissible travel, along the axis ⁇ 2, by the nut P0 2! 4 , is defined by two stops consisting of two plates P0 22 , P0 223 , housed in a recess P0 224 , and integral with the cradle POioo-
• the P0 224 recess, of parallelepiped shape is located in the central part of the POioo cradle, the opening facing the POioi screw, its depth being slightly less than that of the deepest generator of the cylindrical cavity P0 2 ⁇ 5 , the width being close to three times the diameter of the mother screw POioi, and its length, along the axis ⁇ 2, slightly less than the length equivalent to the sum of the lengths of the nut P0 2i4 and the two rings P0 2 ⁇ 6 , P0 2 ⁇ 7 .
• the rectangular plates P0 222 , P0 223 are located in the bottom of the abutment P0 22 , on either side of the nut P0 2 ⁇ 4 , and integral with the cradle POioo-
• the two rings P0 2 ⁇ 6 , P0 2i7 have a shoulder of smaller diameter than that of the cylindrical cavity P0 2 ⁇ 5 , on the side of their bearing face with the nut P0 2 ⁇ 4 .
• the abovementioned rectangular plates P0 2 2 , P0 223 have, at each of their ends, lugs coming to bear on the abovementioned shoulders of the two rings P0 2 ⁇ 6 , P0 2! 7 .
• the nut P0 2 ⁇ 4 has two flats, symmetrical with respect to the axis ⁇ 2, located in a plane parallel to the plane defined by the axes ⁇ 2, ⁇ 3.
• the two rectangular plates P0 222 , P0 223 bear on the above-mentioned flats of the nut P0 2J4 .
• the length of these bearing surfaces being greater than the length of the nut P0 214 , it can thus move on either side of the point of equilibrium by a distance equal to half the difference in length between the bearing faces of the two plates P0 222 , P0 223 , and the length of the nut P0 2 ⁇ .
• PO 202a , PO 2 02b, PO 203a , PO 203 b ball rings, integral with the POioo cradle, allow the movement of said cradle along the guide columns, respectively PO 202 , PO 203 , integral with the cradle P0 2 oo -
• the second cradle is shown in cross section along the plane containing the axis ⁇ l and pe ⁇ endicular to the axis ⁇ 2; in the example shown in Figure 45a, the second cradle is shown in cross section along the plane containing the axis ⁇ l and pe ⁇ endicular to the axis ⁇ 3; in the example shown in Figure 45b, the second cradle is shown in cross section along the plane containing the axis ⁇ 3 and pe ⁇ endicular to the axis ⁇ l.
• the POioi lead screw is pivotally mounted:
• the mother screw PO 101 drives a threaded nut POn 4 , of circular section; the aforesaid nut POn is not directly integral with the casing Ca of the transfer head T, as indicated above; a mechanism makes it possible to associate with said nut PO ⁇ a degree of freedom along the axis ⁇ l.
• the nut PO ⁇ is positioned between two rings POn 6 , POn 7 , of section circular, of length close to that of the nut POn 4 , and sliding freely in a cylindrical cavity POn 5 , concentric with the axis ⁇ l.
• a crew POn 8 of the nut POn 4 , of parallelepiped shape is maintained in a cavity in shape correspondence with said crew co POs PO ⁇ g, in the housing Ca of the transfer head T.
• Said crew co ⁇ s POn 8 includes:
• the two rings POu 6 , PO n7 located on either side of the nut POn 4 , each have, on the side opposite their bearing face with said nut POn 4 , a circular recess making it possible to accommodate a spring.
• Two flanges POn 9a , POn 9b secured to the crew POn 8 , each comprising a cylindrical orifice with a diameter slightly greater than the diameter of the mother screw POioi, seal the coaxial cavity POn 5 and constitute a stop for each spring.
• Two springs PO ⁇ 26 , PO ⁇ 27 , mounted in compression are thus held in the two cavities, located on either side of the nut POn 4 , consisting of the cylindrical cavity POn 5 and respectively, of the ring PO ⁇ 6 and of the POn flange 9a , and POn ring 7 and POn flange 9b .
• the nut PO ⁇ is held between two half-moons PO ⁇ 22a , PO ⁇ 22 , of width equal to a circular shoulder located on the periphery of said nut PO 114 , internal diameter equal to the external diameter of said shoulder of the nut PO n 4 and of external diameter slightly less than the thickness of the crew co ⁇ s PO ⁇ ; said half-moons P0 122a , PO ⁇ 22b , are integral with the nut POn 4 by two clamping screws not shown.
• Two shoulder screws PO ⁇ 23a , PO ⁇ 23b are screwed into the half-moons, respectively PO ⁇ 22a , PO mb along the axis ⁇ 12; said shoulder screws PO ⁇ 23a , PO ⁇ 23b each maintain a ball bearing and a spacer, respectively PO ⁇ 24a , PO ⁇ 25a , and PO ⁇ 24b , PO ⁇ 25b ; the outside diameter of said ball bearings PO ⁇ 24a , PO ⁇ 24b is slightly less than the width of the oblong section of the above cavities PO ⁇ 2 ⁇ a , POi 2 i b -
• the nut POn 4 can move on either side of the point of equilibrium by a distance equal to half the difference between the length of the oblong section of the above cavities PO ⁇ 2 ⁇ a , PO J i b , and the outside diameters of the above ball bearings PO ⁇ 24a , PO ⁇ 24b .
• Ca of the transfer head T allow the displacement of said co ⁇ s along the guide columns, respectively PO ⁇ 02 , PO ⁇ 03 , integral with the cradle
• the transfer head T comprises four sub-assemblies: - an extractor E, intended to allow the transfer head T to be positioned around the electrode to be extracted, then to extract it by pinching said electrode followed by a rotational movement, - a charger C, intended, after displacement of the transfer head T, to replace the extractor E, to place the new electrode on the holder electrode, - a motorized group Mo, intended to drive the extractor E in rotation, to activate and deactivate the positioner-blockers,
• the aforesaid transfer head T consists of a housing Ca, of complex shape, essentially parallelepiped, associated with two plates Pex, Pmo, respectively "extractor plate” and “motor plate”.
• the casing Ca includes a number of bearing surfaces, flat and cylindrical, making it possible to position and secure the following sub-assemblies:
• the motor plate Pmo secured to the casing Ca along a vertical bearing face pe ⁇ endicular to the reference plane ⁇ and disposed at one end of said casing Ca, supporting a motor whose main axis ⁇ 9 is parallel to the reference plane U, and a transmission by pulleys and toothed belts,
• the transfer head T comprises, as indicated above, the motor plate Pmo comprising:
• the pulleys T 2 , T 4 are of diameters smaller than those of the pulleys T 3 , T 5 , so as to reduce the angular rotation speed of the shaft T ⁇ 0 relative to that of the motor shaft Ti and thus to increase the torque transmitted by said shaft T ⁇ 0 .
• the above-mentioned motorized group Mo comprising the plate Pmo, the motor Ti, the pulleys T 2 , T 3 , T 4 , T 5 , the belts T 6 , T 7 , drives the shaft T ⁇ 0 of the extractor sub-assembly E by means of the friction mechanism T 9 .
• the shaft T 10 comprises, over approximately a quarter of its length, a cylindrical surface supporting a bush Tu, integral with the shaft T 10 ; the aforesaid bush Tu is made integral with the pulley T 5 by means of the friction mechanism T 9 , bearing on the pulley T 5 by means of another bush T ⁇ 2 , in two parts enclosing said pulley T 5 .
• the cylindrical bearing of the shaft T ⁇ 0 also supports two ball bearings T ⁇ 3 , T ⁇ 4 , integral with the casing Ca of the transfer head T; thus, the Tio shaft is pivotally mounted in said housing Ca.
• the T ⁇ 0 shaft also comprises, over approximately three quarters of its length, a threaded part, constituting a lead screw.
• This threaded part drives a rack T ⁇ 5 , of cylindrical section whose main axis is collinear with the axis ⁇ 10, the bore of said rack T 15 being threaded in accordance with the shape of the threaded part of the shaft T ⁇ 0 .
• the rack T ⁇ 5 has two parallel flats, arranged over its entire length, symmetrical with respect to the axis ⁇ 10, the two flats being parallel to the so-called reference plane ⁇ .
• One of the above-mentioned flats has a series of straight teeth, the other flap constitutes a guide bearing in rotation, the rack T ] 5 being able to slide in the housing Ca by means of two guide rings T ⁇ 6 , T ⁇ 7 , integral with the housing Ca , located at the opposite end to that of the cylindrical bearing of the shaft T 10 .
• a guide roller T ⁇ 8 located between the above rings T i6 , T 17 , whose axis ⁇ 14 is parallel to the plane called reference II and perpendicular to the axis ⁇ 10 of the rack T ⁇ 5 , is supported on the flat constituting the anti-rotation guide range.
• a rotational movement of the shaft T ⁇ 0 causes a translational movement of the rack T ⁇ 5 , along said axis ⁇ 10; which translational movement of the rack T 15 causes a rotational movement of a pinion T ⁇ 9 , secured to a shaft T 20 , whose main axis is the axis ⁇ 6, previously defined, the teeth of said pinion ⁇ 9 being conformity of form with the abovementioned series of straight teeth of the rack T 15 .
• the drive assembly of the extractor E whose main axis ⁇ 6 is pe ⁇ endicular to the axis ⁇ l and parallel to the so-called reference plane II, said assembly being associated with the the aforementioned rack T ⁇ 5 , includes: - the Pex plate, defined above, secured to the housing Ca,
• the shaft T 20 the main axis of which is collinear with the axis ⁇ 6, pivotally mounted by means of two ball bearings T 21 , T 22 , integral with the casing Ca, and located approximately in the central part of said tree T 20 ; furthermore, said shaft T 20 has a shoulder in excess thickness close to the upper bearing T 22 ,
• a shaft T 23 the main axis of which is collinear with the axis ⁇ 6, is integral with the aforesaid shaft T 20 at its lower end, and drives an angular position sensor T 24 , the stator of which is integral with the casing Ca, - a pinion T 25 , the main axis of which is collinear with the axis ⁇ 6, mounted clamped between two lower and upper coaxial rings, respectively T 26 , T 27 ,
• a cam T 3 ⁇ pivotally mounted around the shaft T 20 , by means of the aforesaid ball bearing T 30 .
• the two coaxial rings T 26 , T 27 integral with the shaft T 20 in rotation, and being able to slide freely on said shaft T 20 , secure the pinion T 25 of the shaft T 20 by means of two washers coaxial friction T 25a , T 25b , thanks to the tightening carried out by the nut T 28 pressing on the ring T 2 via the set of washers T 29 , the ring T 26 being supported on the abovementioned shoulder in extra thickness of the shaft T 20 .
• a pin not shown, whose main axis is parallel to the axis ⁇ 6, integral with the coaxial ring T 26 , rotates the cam T 3 ⁇ .
• the electrode extraction mechanism is identical in all respects to the mechanism described above, concerning the first example of an electrode transfer device according to the invention, said extraction mechanism being coaxial with the axis ⁇ 7, housed in the above bore of the Pex plate and maintained between the two lower and upper plates, respectively Pexa, Pexb.
• the extractor E comprises, in addition to the elements described above, an articulated arm T 32 , oscillating around a shaft T 33 , the central axis ⁇ 15 of which is parallel to the axes ⁇ 6, ⁇ 7 and situated at the top of an isosceles triangle whose base is defined by said axes ⁇ 6, ⁇ 7; this swing arm T 32 is actuated, in its central part, by the cam T 3i ; it has at one end, close to its axis of articulation ⁇ 15, a locking lug oriented towards the extractor, and at its other end a hinge shaft T 34 making it possible to drive, in horizontal translation, a shoe T 35 , which drives, via four cannons T 36a ⁇ b,, d, the four sheathed cables which actuate the four positioner-blockers PB1, PB2, PB3, PB4.
• the articulated arm T 32 controls, via the cam T 31 , on the one hand, the extractor in the clamping position and, on the other hand, the blocking or unblocking of said positioner-blockers, depending on the angular position of said cam T 31 .
• Two locking pins T 39 , T 40 located in the corner opposite to the shaft T 34 of the Pex plate, are arranged on either side of the extractor; both are urged each by a compression spring, not shown, so as to be in contact, respectively, with the upper part T 38 ⁇ and with the lower part T 382 , of the jaw support crown T 38 .
• the aforesaid jaw support crown T 38 comprises five jaws T 38a , T 38b , T 38c , T 3 g d , T 38e , not shown, articulated respectively around the shafts T 38a ' , T 38b' , T 38c >, T 38c i ' , T 38e >.
• a toothed crown T 37 concentric with the jaw support crown T 38 , is driven by the pinion T 25 , and in turn, drives the toothed parts of said clamping jaws T 38a , T 38b , T 38c , T 38d , T 38th .
• This assembly is identical to that described above under the first example of an electrode transfer device.
• FIGS. 54 to 57 represent the four stages concerning the blocking of the electrode in the extractor and the rotation of said electrode so as to separate it from its electrode holder.
• the lug of said arm is inserted into a notch in the lower part T 382 of the jaw support ring T 38 , blocking in rotation the jaw support ring T 38 ,
• the shaft T 34 drives the shoe so as to pull on the cables of the four positioner-blockers, causing the unlocking of said positioner-blockers.
• the pinion T 25 rotates counterclockwise, the toothed crown T 37 rotates clockwise, which, by reaction effect due to the presence of said jaws, tends to rotate the support crown jaws T 38 counterclockwise; moreover, said jaw support ring T 38 is locked in rotation, on the one hand, by the lug T 39 at the level of the upper part T 381 and, on the other hand, by the lug of the arm T 32 at level of the lower part T 382 .
• the electrode is also driven clockwise and separates from its electrode holder.
• the lower lug T 40 engages in a notch located in the lower part T 3 g 2 ; which has the effect, during the fourth step, of blocking the rotation of the jaw support crown T 38 and of maintaining the electrode between the five clamping jaws.
• the charger C consists of a barrel T 4 ⁇ whose main axis is the axis ⁇ 8; said barrel T 4J comprises a plurality of lids intended to receive the electrodes; unlike the barrel, referenced 21, of the first example of an electrode transfer apparatus, said barrel T 41 comprises lids which can alternately receive electrodes, the tubular part of which is sometimes oriented upwards, sometimes oriented downwards; a metal ring elastic, not shown, keeps the electrodes in the lids.
• a shaft T 2 pivotally mounted in the casing Ca, makes the above-mentioned barrel T 4 ⁇ integral with a disc T 44 which, by means of a nut T 43 , is screwed at the level of the upper part of said shaft T 42 .
• the disk T 42 is identical to that described in the first example under the reference 42; it includes, identically, a plurality of branches of a number equivalent to that of the plurality of lids situated on the barrel, all of these said branches representing a Maltese cross.
• a disc T 45 the main axis of which is ⁇ l l, comprises, in the manner previously described under the reference 40, a first tenon of section in a half-moon T 46 (ex 44) and a second tenon of circular section T 7 (ex 45).
• the above-mentioned disc T 45 is secured to a shaft T 49 , which is secured to a disc T 50 , the assembly being coaxial with the axis ⁇ l 1.
• the angular displacement of the disc T 44 is transmitted to the barrel T 4 ⁇ and thus makes it possible to position the electrode opposite the corresponding housing of the electrode holder.
• the 360 degree rotational drive of the assembly T 45 , T 48 , T 50 is carried out by means of a rack T 52 , the main axis of which is ⁇ 12; the aforementioned rack T 52 drives in rotation, during its longitudinal displacement, a free-rotating equipment around the shaft T 48 , namely: a pinion T 49 , in connection with the above rack T 52 and a drum T 5 ⁇ , integral with the above pinion T 49 .
• the drum T 5 ⁇ comprises a ratchet T 54 whose axis of rotation ⁇ l l "is parallel to the axis ⁇ l l, which ratchet is in shape correspondence with a notch made on the peripheral surface of the disk T 50 ; during the rotation of the drum T 51 , driven by the translation of the rack T 52 , the ratchet T 5 in turn drives the disc T 50 and therefore the disc T 45.
• the backward movement of the rack T 52 does not cause the disc T 50 , given the non-reversibility of the ratchet T 5 and the presence of a second ratchet T 53 in correspondence of shape with a notch on the peripheral surface of the disc T 45 , which ratchet T 53 has its axis of rotation ⁇ l parallel to the axis ⁇ l l.
• the round-trip movements of the above rack T 52 are carried out during the movements of the transfer head T; in fact, the rack, passing right through the casing Ca, protrudes by a length corresponding to the plurality of teeth necessary to rotate the above pinion T 49 by 360 °; thus, each time the transfer head T is brought into abutment during its movement along the axis ⁇ l, the rack T 52 is introduced towards the inside of the casing Ca; the 360-degree rotational movement of the assembly described above is carried out at the end of translation of the transfer head T, from its loading position to its extraction position.
• a detector for the presence of electrodes T 55 is positioned on the casing Ca so as to generate an optical beam which will be reflected by the electrode in the event of its presence, or by a reflector situated beyond the barrel T 41 , in the absence of an electrode in said barrel T 41 .
• a mechanism will be provided for verifying the operation of the extractor by means of the absence of an electrode on the electrode holder as well as the loading of the new electrode by the presence of the latter on the holder. -electrode.
• a mechanism associated with the transfer head T and the tool holder PO, makes it possible, during the phase of extraction of the electrode from its electrode holder, to limit the stroke, along the axis ⁇ 2, of said transfer head T, on either side of the middle position.
• a finger T 55 integral with the cradle P0 20 o, is positioned in the center of one of the external faces of said cradle P0 2 oo, and oriented in the direction of the transfer head T.
• two pawls T 56a , T 56 pivotally mounted around their shaft, respectively T 57a , T 57b , which are integral with the flange POn 9b of the PO ⁇ crew 18 and their axis, respectively ⁇ 16a, ⁇ 16b, is parallel to the axis
• the above-mentioned pawls T 56a , T 56 are arranged head to tail, on either side of the axis ⁇ l, at a distance equal to the width of the above-mentioned finger T 55 , and are each actuated by a spring, not shown. , so that their respective bearing surface is pe ⁇ endicular to the so-called reference plane ⁇ .
• the finger T 55 causes the lower pawl T 56 to tilt by a neighboring angle 45 degrees counterclockwise, allowing passage to the transfer head T; the finger T 55 , arriving in the middle position, comes into abutment low against the bearing surface of the upper pawl T 56a .
• the finger T 55 causes the upper pawl T 56a to tilt by an angle close to 45 degrees clockwise, allowing passage to the transfer head T; the finger T 55 , arriving in the middle position, comes into high abutment against the bearing surface of the lower pawl T 56b .
• the mechanism described above makes it possible, in the extraction position of the transfer head T, to limit the stroke of said transfer head T to approximately half the stroke defined by the cradle P0 20 o along the axis ⁇ 2, on either side of the middle position.
• the sequence for changing the electrodes is as follows:

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• 2002
  • 2002-10-17 FR FR0212954A patent/FR2845938B1/fr not_active Expired - Fee Related
• 2003
  • 2003-10-16 EP EP03776969A patent/EP1551587A2/de not_active Withdrawn
  • 2003-10-16 AU AU2003286226A patent/AU2003286226A1/en not_active Abandoned
  • 2003-10-16 WO PCT/FR2003/003062 patent/WO2004035251A2/fr not_active Application Discontinuation

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