EP0300984B1 - Manipulator for metal sheets - Google Patents

Abstract

The manipulator comprises a support structure 1 with a vice 5 vertically disposed capable of grasping a plate sheet 22 and carrying it to the press 23, the plate sheet performing a rigorously linear course. The support structure is intended to perform a rototranslatory motion, rotating around pivot 11 which is located corresponding to the extremity of the support structure opposite to the extremity in which the vice 5 is placed. This pivot slides along guide 13 which is located laterally with respect to the direction of advance of the plate, the direction of the guide being perpendicular with respect to the direction of advance of the plate. The energy required to transport the plate from the loading zone to the press is reduced to about one-half with respect to the energy required in similar devices of known type in which a support structure which carries the plate sheet from the loading zone to the press performs exactly the same course of the plate (see FIG. 3).

Description

The present invention relates to a manipulator for sheet metal sheets. Such a manipulator, in accordance with the preamble of claim 1, is known from document JP-A-58-168 445.

Manipulators for metal sheets are known in the form of flat sheets, which are capable of picking them up from a loading area and then bringing them to a press brake which ensures the folding of one or more of their edges.

Once folded and welded to each other appropriately, these sheets are used both in the automotive sector for the production of vehicle hulls and in the field of household appliances (refrigerators, washing machines, air conditioners) or for the production of shelving for furniture and the like.

In the current state of the art, manipulators are known comprising in particular a jaw provided with two opposite jaws oriented vertically and suitable for gripping each sheet in the loading area to bring it to the press; this jaw has the possibility of turning around its axis in one direction or the other, thereby causing the rotation of the sheet metal sheet which can be subjected to the folding operation at all its sides.

In one of these devices, it is provided that the two jaws of the jaw are mounted at the end of a C-profile structure which is capable of performing only a linear movement, the jaw thus always always facing towards the sheet insertion area in the press.

The loading of the sheets on the manipulator must necessarily be carried out in a direction transverse to that of advance of the manipulator.

The main disadvantage of such a device lies in the fact that it is absolutely impossible to load a sheet on the manipulator before the latter has unloaded the previous sheet and has completed the reverse return stroke so as to have rear relative to the loading device. In addition and the fact that the manipulator, which constitutes a large mass structure, performs a movement of advance exactly equal to that accomplished by the sheet, it is understood that It is essential to have recourse to a large power motor, which determines an increase in the cost of the device as well as an increase in the energy consumption necessary for the movements of the latter.

In another manipulator of known type, the jaw is supported by a gantry-shaped structure, which also has only one possibility of linear movement from the loading area to the press.

The fundamental drawback of such a structure lies in its large transverse size, since the distance which separates the two columns must be greater than the greatest diagonal of the sheet of metal in order to allow the angular displacement of the latter; moreover, the gantry guides are very stressed and tend to deform, determining, in the final analysis, a certain imprecision in the folding operation. In addition, even in this case also, it is necessary to move the entire large mass of the gantry by an amount equal to the displacement printed on the sheet of sheet metal. Compared to the previous device, it is however possible to have in the loading area a new sheet of sheet metal immediately after the gantry has left it to go towards the folding area.

In both devices, there are jaws which are capable of turning only at an angle of 90 ° and 180 °, which excludes for example the possibility of working a sheet of sheet metal which is not rectangular in profile.

The present invention proposes to produce a manipulator device for sheets which has advantageous structural and functional characteristics compared to those of similar devices of known type.

Another object of the invention is to provide a manipulator which includes a device for securely locking the jaw in any position desired by the user, while being capable of allowing the rotation of the jaws which grip the sheets at angles of any desired value and in particular different from 90 ° and 180 °, as is the case similar devices of known type.

The manipulator for sheet metal sheets according to the invention is defined in claim 1.

The invention in fact provides that the support structure of the upper jaw, having a double T-shaped profile, is articulated, at its side opposite to that on which said upper jaw is mounted, on a carriage which can move on a guide oriented in a direction perpendicular to that of the path taken by the sheet to reach the press. Vice versa, the lower jaw is mounted on a vertical shaft. The latter constitutes the connecting pivot between the lower lateral end of the support structure and a longitudinal carriage which is provided with the possibility of moving in the direction of advance of the sheet.

When the longitudinal carriage is moved forward in order to determine the advance of the sheet, the transverse carriage is able to move along its guide, the whole structure thus achieving a "feathered" movement with " the pole "nevertheless mobile so that the two jaws and consequently the sheet move in a perfectly rectilinear movement. There are also provided specific means to allow and determine the rotation of the two vertical jaws about their own axis, in order to allow the press to work on all sides of the sheets.

In a preferred embodiment of the invention, an effective locking means is provided for the lower jaw, which makes it possible to stop the angular travel of this jaw at any desired value and not only at three or four pre-established positions. , as in known type devices. In practice, around a part of the shaft of which the jaw is integral, is arranged a cylindrical annular chamber whose partition wall with the aforementioned shaft is intended to bend once said chamber is filled with 'a fluid under pressure, in order to exert a force on the shaft to prevent rotation.

Of course, there are provided specific means for determining the rotation of the shaft which carries the lower jaw, the movement of the latter being naturally taken up by the upper jaw.

Advantageously, an automatic device will be provided for controlling the angular position of the jaws in order to satisfy the particular requirements for bending the edges of the sheet metal sheet.

It is easily understood that the energy necessary to ensure the movement of the movable members of the manipulator is much lower than that necessary to operate the movement of the movable members of the manipulators of known type; in fact these latter members are intended to follow a path exactly equal to that made by the sheet from the loading area to the press, while in the device according to the invention, the movement accomplished by the baricenter of the movable members is almost half that of sheet metal. In addition, in the device according to the invention, it is possible to have a new sheet of sheet metal in the loading area at each instant following the moment when the previous sheet was gripped by the manipulator to be brought to the press. folder, loading can also occur when the manipulator is returned to position for picking up a new sheet.

The unloading of the folded sheet can be carried out from the moment when the two jaws open until the moment when the manipulator is ready to start again to bring a new sheet to the press.

In the device according to the invention, it is also possible to carry out the loading and unloading of the sheets of sheet metal both on the right and on the left (the loading can also be carried out from the front), reverse of similar devices of known type where the loading must necessarily take place in a single direction.

All this considerably reduces the time that elapses between the loading of the sheet on the manipulator and the arrival of the latter on the press brake. Thanks to the particular movement of the movable parts of the manipulator, which requires energy approximately reduced by half compared to similar devices of known type, it is possible to use for the movement a motor of power approximately half that required for the aforementioned devices, although heard with equal mass of the manipulator, which reduces the cost of the latter and simultaneously the energy consumption necessary for its use.

• La fig. 1 est une vue en élévation de l'ensemble du dispositif suivant un mode de réalisation de l'invention.
• La fig. 2 montre en coupe partielle un détail de ce dispositif.
• Les fig. 3 , 4 et 5 constituent chacune une vue en plan schématique par dessus du dispositif, montré au cours de trois phases différentes du fonctionnement.

The foregoing characteristics and still other characteristics of the invention will now be illustrated in detail with reference to a particular embodiment of said invention, with the aid of the appended drawings, in which:

• Fig. 1 is an elevational view of the entire device according to an embodiment of the invention.
• Fig. 2 shows in partial section a detail of this device.
• Figs. 3, 4 and 5 each constitute a schematic plan view from above of the device, shown during three different phases of operation.

In fig. 1, it can be seen that the device according to a particular embodiment of the invention comprises an upper support element 1 articulated in 2 to a lower support element 3; this structure affects the general shape of a double T.

At one of their wings, the two support elements are connected by a hydraulic jack 4 whose body is fixed to one of said elements, while the rod is made integral with the opposite element; this jack is able to intervene to cause the rotation of the upper element 1 around the pivot 2, with a view to bringing the two wings closer to the support elements assembled by said cylinder while simultaneously moving the opposite wings apart from one another. At the level of the wing of the upper support 1 opposite to that which is associated with the jack 4, an upper jaw 5 oriented vertically and capable of rotating about its own axis is provided. the lateral end of the lower support element 3 is profiled so as to present a series (two in this case) of teeth 6 engaged in the spaces provided between the corresponding teeth 7 provided on a longitudinal carriage 8; the lower support element 3 and the carriage 8 are connected to each other in a rotary manner by means of a shaft 9, oriented vertically and integral with a lower jaw 10, said shaft being arranged inside seats in teeth 6 and 7.

Downwards, the lower support element 3 is extended by a pin 11 mounted on a transverse carriage 12 movable along a guide 13. The entire structure is supported by a fixed base 14 which has a horizontal part facing the above-mentioned guide, while at its vertical part faces the longitudinal carriage, which is connected to it in the same way by pads 15, arranged horizontally and suitable for moving along linear guides 15 'advantageously from ball circulation type. On the longitudinal carriage 8 is further provided a motor 16, electric or hydraulic, for driving in rotation a toothed wheel 17 cooperating with a rack 18 which is carried by the vertical part of the fixed base and which s' extends longitudinally. On the longitudinal carriage is mounted another electric motor 19 with a vertical axis which cooperates by means of a pinion 20 with a toothed wheel 21 whose axis is oriented vertically and which is integral with the lower end of the shaft 9.

Referring to fig. 3, it can be seen that the sheet metal sheet 22 which has just been loaded onto the manipulator using suitable devices, not illustrated in the drawing because of known type, is intended to be gripped by the clamp formed by the two jaws, preferably at its central part. In fig. 3, it can be seen that the loading takes place from right to left in the transverse direction with respect to the direction of advance of the sheet from the loading zone to the press 23. In the loading position, the transverse carriage and therefore the pivot 11 are located at the level of the anterior end of travel of the guide 13, as illustrated in the figure. On the latter, we can see that there is no problem opposing the fact that the manipulator can be loaded on the left or on the back.

In this figure, we can still see a sheet 25 already subjected to the folding operation on two of its edges, and which is removed from the working area, for example using pliers 24.

In fig. 4 and 5, it can be seen that when the electric motor referenced 16 in FIG. 1 begins its rotation, it determines the movement of the longitudinal carriage, not shown in the drawing for the purpose of simplification, relative to the fixed base, the latter not having itself been shown for clarity; of course the transverse carriage is intended to move along the guide 13, being carried at the end part of said guide towards the half of the path (fig. 5) which goes from the loading area to the press, to then return once again to the level of the most advanced part of the aforementioned guide (fig. 4). It goes without saying that if the carriage performs a strictly rectilinear movement, the lower support element 3 performs a rotation-translation movement by turning around the pivot 11, which in turn moves on the guide 13 in a rectilinear movement.

At the end of the travel of the longitudinal carriage, the sheet 22 is in position so that one of its edges can be folded by the press 23. If it is necessary to fold the other edges of this sheet, it is understood that the support elements 1 and 3 are moved back, also in this case following the rotation of the electric motor which determines the displacements of the longitudinal carriage, in order to allow the rotation of the sheet metal, determined by the movement of the electric motor 19 to through the toothed wheel 21, the shaft 9 and therefore the lower jaw 10.

In fig. 5, there has been illustrated in broken lines the limit of the space occupied by the sheet during this rotation, the rear limit of this circumference in practice determining the most advanced position at which the next sheet 22 can be brought, which must be loaded during the folding phase of the previous sheet. It is possible to pre-arrange the upper jaw 5 so that it is mounted idly inside the seat provided on the upper support 1, its rotation being ensured by the torsional force than through the sheet exercises on it the lower jaw 10.

As a variant, the upper jaw can be connected to the lower jaw 10 by means of mechanical deflection devices, housed inside the body of the carriage 8 and of the support elements 1 and 3; this solution, although more complex from a structural point of view compared to the previous one, has the important advantage of allowing the two jaws to always perform the same angular movements.

It is effectively structurally impossible to ensure that the axes of the two jaws are perfectly superimposed; if these two axes are always in the same position, the dimensions of the bending will be constant for each sheet, while if the axes are arranged offset, each sheet will have different final dimensions from the previous one.

In fig. 4 and 5, it can be seen that the unloading of the sheet 25, already folded along its edges, which will be carried out using a device of known type, using for example a clamp 24, can occur from the moment during which the two jaws open up to where the manipulator, after being loaded with a subsequent sheet, again comes close to the press; in fact and for safety reasons, we limit ourselves to delaying this operation until the moment the manipulator leaves the loading area.

In accordance with a preferred embodiment of the invention, a special mechanism is provided for blocking the angular position of the lower jaw 10 (FIG. 2). Around the outer wall of the shaft 9 integral with this jaw, and on one of the teeth 7 of the longitudinal carriage 8 is in fact formed an annular cylindrical chamber 26 which through a pipe 27 can be filled with a hydraulic fluid , for example from a hydraulic pump or the like. The inner wall which forms the chamber 26 and which constitutes the element separating it from the outer wall of the shaft 9 is very thin and can therefore be elastically deformed appreciably when the fluid pressure exceeds a certain value. predetermined, thereby interfering with the wall of the shaft and prohibiting any subsequent rotation thereof, so that the blocking is thus ensured.

This type of blocking has the important advantage of being extremely precise at all the angular positions of the shaft and consequently it lends itself particularly well to allow the bending of the sheet to any angular position. More specifically, this arrangement makes it possible to work sheet metal sheets having a profile different from the rectangular profile. It should also be considered that the sheets are sometimes cut irregularly with different shapes from the exact rectangular profile. In the case where two sheets must be superimposed, it is necessary that the edges correspond perfectly and by operating with the above-mentioned device, it is possible to allow the sheet to be folded so that the fold obtained is strictly parallel at the end edges of said sheet, thereby allowing the imperfection of the cut to be recovered and in particular to use a sheet which would otherwise have to be discarded.

Claims (7)

1. Manipulator for metal sheets, of the type comprising a supporting construction with two clamping jaws (5-10) orientated vertically and aligned axially so as to grip, level with the feed zone, a horizontally arranged metal sheet (22), said construction incorporating actuating means for allowing the metal sheet to be moved linearly until it reaches a bending press (23), devices being associated with said jaws (5-10) in order to fix their rotation about their axis, so as to allow the sheet to be subjected to a bending operation on all or some of its sides,
   characterised in that the supporting construction is shaped overall like a double T with an upper element (1) which, at the extremity of one of its sides, comprises the seat for the shaft of the upper jaw (5), and a lower support element (3) articulated (at 2) to the former in the central joining region, said lower support element (1) continuing downwards by way of a trunnion (11) mounted on a transverse carriage (12) which runs along a guide (13) orientated perpendicularly to the line joining the zone for feeding the sheet metal and the press, said guide (13) being provided laterally with respect to the aforementioned line, its direction intersecting said line at the halfway level, the guide (13) being carried by a fixed shoulder (14) which laterally with respect to the jaw zone continues vertically, the lateral extremity of the lower support element (3) being articulated, by the shaft (9) which supports the lower jaw (10), to a longitudinal carriage (8) which on the side incorporates lugs (15) adapted to move along linear guides (15') provided on the vertical portion of the foregoing shoulder (14), these linear guides (15') extending parallel with respect to the line joining the feed zone and the press, means (16-17-18) being provided to ensure forward motion of the longitudinal carriage (8) along these linear guides (15') and also means (19, 20, 21) for generating rotation of the shaft (9) and hence that of the lower jaw (10).
2. Manipulator according to claim 1, characterised in that the means for ensuring the forward motion of the longitudinal carriage (8) are constituted by a motor (16) carried by the carriage and horizontally orientated so as to rotate a toothed wheel (17) which meshes with a rack (18) provided on the vertical portion of the shoulder (14), which rack (18) extends parallel to the orientation of the linear guides (15').
3. Manipulator according to either of claims 1 and 2, characterised in that the means for enduring the rotation of the shaft (9) are constituted by an electric motor (19) carried by the longitudinal carriage (8) in order to ensure the rotation, by way of a pinion (20), of a toothed wheel (21) rigidly joined coaxially to the aforementioned shaft (9).
4. Manipulator according to any one of claims 1 to 3, characterised in that the two support elements (1-3) are joined to one another, at their side opposed to that carrying the jaw (5, 10), by beans of a hydraulic-type actuator (4) whose body is rigidly joined to one of the aforementioned elements (1, 3), whilst the upper extremity of the rod thereof is secured to the opposed support element, the displacement of sad rod being adapted to generate the rotational movements of the upper element (1) about the central pivot (2) of said elements.
5. Manipulator according to any one of claims 1 to 4, characterised in that the lateral extremities of the lower support element (3) and of the longitudinal carriage (8) which mutually face one another are configured to present a set of teeth which then engage between the teeth of the opposed element.
6. Manipulator according to any one of claims 1 to 5, characterised in that about the shaft (9) which carries the lower jaw (10) there is provided a cylindrical annular chamber (26), the wall which separates this chamber from the outer wall of the shaft (9) being made from an elastic material of reduced thickness, the device including means for ensuring entry of a pressurised fluid into the interior of said chamber via a conduit (27) incorporated in the body of the carriage (8).
7. Manipulator according to any one of claims 1 to 6, characterised in that it comprises mechanical return means housed inside the bodies of the longitudinal carriage (8) and of the two support elements (1, 3), said means being adapted to mechanically link the two jaws (5-10) and to ensure identity of the angular displacements of said jaws about their axis.

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