Manipulator assembly

Abstract

A manipulator assembly for manipulating sheet metals to be sub j ected to forming by means of a press, in particular metal discs to be drawn or curved, comprising a first manipulator (10) and a second manipulator (12). The first manipulator (10) comprises two first end support elements (14) suitable for forming two sheet metal support points lying on a horizontal plane, said two first end support members (14) being vertically translatable. The second manipulator (12) is a cartesian manipulator comprising a third end support element (16) suitable for forming a third sheet metal support point.

Description

"MANIPULATOR ASSEMBLY"DESCRIPTION

[0001] The present invention relates to a manipulator assembly for manipulating sheet metal to be subj ected to forming by means of a press , in particular metal discs to be drawn or curved, for example for pressuri zed tanks and apparatuses .

[0002] A first method for the industrial production of ends consisted in the use of presses using hydraulic actuation in order to form the ends using a hot process starting from flat discs heated to a temperature higher than that of normali zation . With the evolution of materials , presses were then developed for cold pressing, but for rather limited thicknesses .

[0003] Mechanical screw presses using a progressive forming method were then introduced . The convex disc was obtained by using "open" molds and manually moving the sheet metal disc between one stroke and the other of the press . Thi s technique requires an additional processing step for forming the edge . For this step, special machines are used, called edging machines .

[0004] Following an increase in demand for tanks and pressuri zed apparatuses , during the years following World War I T , manufacturers switched from mechanical screw presses to hydraulic presses which enabled the use offorces with values decidedly higher than those obtainable with mechanical presses .

[0005] With forces of 150 to 300 tons , a new range of thicknesses could be cold pressed, easily reaching 20 mm for construction steels .

[0006] By using hydraulic presses for convex ends it was possible to produce a large range of diameters , within the limit of the width of the press portal , and using molds of considerably smaller dimensions than those for the hot method .

[0007] The width of the press portal and the increase in the thicknesses that may be cold machined have made it possible to create edging radii that are even greater than 300 mm in width . At this point , the need has arisen to design solutions for handling large discs within the portal of the press . Auxiliary devices have therefore been developed, intended for the manipulation of discs , which are referred to as disc manipulators .

[0008] A known disc manipulation system consists of a floating j ib with a chain-mounted electric hoist . A portal press requires a gap between the crosspieces that is suf ficient to house the mold assembly and the upper and lower mold holder tables . The disc li ft system consists of a chain operated by an electric winch or electrohydraulic system, mounted on a ib structure fixedto the upper crosspiece of the press . The chain is fastened on a pin that passes through the center of the disc such that it may be disassembled when it is necessary to press the central part . To press the central part , it is necessary to use a double li ft with diametrically opposite grippers on the edge of the disc . An additional li ft is also required on the opposite side of the press .

[0009] Such a system allows for the vertical li fting of the disc, while the rotation necessary for the angular displacement with respect to the mold pack is manual .

[0010] The larger the diameter and weight of the disc, the greater the number of operators required to rotate the disc .

[0011] The pressing command is cyclical with a timer or is controlled by the operator . It follows that the operators are within the work area and directly involved in displacing the disc, also during the press ing step .

[0012] This system has made it possible to make convex discs of a diameter and weight never before made using cold presses . However, it is slow and requires a massive use of labor, even up to ten operators for discs with diameters greater than five meters . This method has therefore been progressively abandoned insofar as it does not comply with those regulations regarding j ob securitythat have since been adopted in almost all countries of the world .

[0013] Another known manipulator is of the combined type with a tiltable crosspiece and a li fting carriage structure divided into two blocks . In this manipulator, the vertical gap of the press must be enlarged insofar as the li fting and rotation system has a footprint inside the portal .

[0014] This manipulator configuration is based upon two separate structures installed on the front and on the back of the press . The front part is a truss that is inclined by a hydraulic actuator with a support running inside the beam that supports a wheel that is in contact with the disc .

[0015] The rear part is a structure that supports a carriage provided with a mechanical movement that slides inside and outside the press .

[0016] Two li fting and rotation systems are mounted upon this carriage , substantially two wheels , wherein the center distance thereof is mechanically adj usted in order to adapt the centers of rotation to the diameter of the discs to be formed .

[0017] The discs are li fted using hydraulic cylinders in synchrony with the raising of the main li fting cylinder of the press . The rotation of the li fting wheels isactuated by hydraulic motors .

[0018] A single operator may control the entire forming process in being able to control each axis from the command console .

[0019] The system makes it possible for the first time to simultaneously form large-diameter discs packaged on top of each other thereby drastically reducing the manufacturing time for convex ends . This multiple disc molding technique facilitates the machining of thin thicknesses and large diameters of stainless steel , which would otherwise be impossible with a single disc due to the excessive machining and surface work-hardening which would have been necessary to obtain a regular shape .

[0020] The obvious disadvantages of this system are the inability to use forkli fts for the loading and unloading of the discs and convex discs within the frontal area .

[0021] Managing the movement of the inclination of the front inclinable truss and the sliding of the third wheel in synchrony with the translation of the carriage of the li fting wheels is also complex .

[0022] This system also requires speci fic operator experience , and the axis positioning speeds are limited due to the complexity of the interpolation of the axes .

[0023] A further known manipulator is of the type with a single carriage integral within a single translating bodyinside the press portal .

[0024] This type of manipulator has greatly expedited the processing times insofar as the movement of the carriage allows for the simultaneous translation of the three support wheels of the disc .

[0025] There remains , however, a certain problem with the positioning of the front wheel which moves by means of a parallelogram system with the entire parallelogram translating within guides in the carriages . A third movement is the sliding movement .

[0026] Three axes are therefore required in order to tilt the disc and adapt the position of the wheel relative to the diameter of the disc . The combination of the movements due to the need to interpolate a hydraulic angular movement and two linear movements ( one hydraulic and the second possibly electric ) is certainly not easy also in view of the inertia involved . For this reason, high speeds and accelerations of these axes are not possible .

[0027] The obj ect of the present invention is to propose a manipulator assembly that is capable of overcoming the limits of the manipulators mentioned above .

[0028] Such an obj ect is achieved using a manipulator assembly according to claim 1 . The dependent claims describe preferred or advantageous embodiments of themanipulator .

[0029] The features and advantages of the manipulator assembly according to the invention shall be made readily apparent from the following description of preferred embodiment examples thereof , provided purely by way of non-limiting examples , with reference to the accompanying figures , wherein :

[0030] - Figure 1 is a perspective view of a manipulator assembly according to the invention, in an embodiment , and of an example of a press whereto it is slaved;

[0031] - Figure 2 is a view similar to the previous one , wherein the press is shown only partially such that all components of the manipulator assembly are visible ;

[0032] - Figure 2a is a plan view from above of a manipulator of the manipulator assembly;

[0033] - Figure 3 is a schematic side view of the manipulator assembly;

[0034] - Figure 4 is a view similar to the previous one , with the manipulator assembly in a di f ferent position; and

[0035] - Figure 5 is a plan view from above of the manipulator assembly in Figure 3 and 4 .

[0036] In said drawings , a manipulator assembly according to the invention has been indicated in the entirety thereof with the numeral 1 .

[0037] The manipulator assembly 1 is suitable for manipulating sheet metal 2 to be formed by means of a press 3 , in particular metal discs to be drawn or curved . The press 3 forms a portal 4 for accessing the mold 5 from opposite sides for forming the sheet metal .

[0038] The manipulator assembly 1 comprises a first manipulator 10 and a second manipulator 12 that are separated therebetween .

[0039] In particular, the first manipulator 10 and the second manipulator 12 are suitable for being positioned facing therebetween on opposite sides of the portal 4 of the press 3 .

[0040] In a general embodiment , the first manipulator 10 comprises two first end support elements 14 suitable for forming two sheet metal 2 support points .

[0041] These two first end support elements 14 lie on a hori zontal plane and are vertically translatable .

[0042] The second manipulator 12 is a cartesian manipulator . The second manipulator 12 comprises a third end support element 16 suitable for forming a third support point for the sheet metal 2 . The term "cartesian" conventionally indicates that the operating member , in this case the third end support element 16 , is moved along three orthogonal axes .

[0043] In an embodiment , the two first end support elements14 are movable for varying the mutual distance thereof .Adj usting the distance between the two first end support elements 14 allows metal discs with signi ficantly di f ferent diameters to be supported .

[0044] In an embodiment , the two first end support elements 14 are hori zontally translatable along a first direction X towards / away from the portal 4 of the press 3 .

[0045] In an embodiment , the first and second manipulators 10 , 12 comprise electromechanical devices for moving the first terminal support elements 14 and the third terminal support element 16 , respectively . The electromechanical devices comprise electric motors and electric axes . The electric motors are used to control the rotation of the first terminal support elements 14 about a respective rotation axis and possibly to adj ust the position of the rotation axes on a plane wherein, as in the embodiment represented in the drawings and described below, the end support elements 14 are implemented by motori zed wheels . The electric axes are used for the translation movements of the terminal support elements 14 , 16.

[0046] In an embodiment , the manipulator assembly 1 comprises a control unit for the electromechanical devices - not shown .

[0047] Furthermore , the manipulator assembly may comprise position sensors suitable for detecting the position ofthe end support elements 14 , 16 .

[0048] The control unit is programmed to control the electromechanical devices according to the position of the terminal support elements 14 , 16 detected by the position sensors such as to implement a predetermined movement cycle of the sheet metal .

[0049] In particular, the control unit is configured such as to interpolate the position of the third end support element 16 with the position of the first two end support elements 14 such as to make the three support points integral therebetween in those planes that are in contact with the sheet metal .

[0050] In an embodiment , the first two end support elements 14 consist of a pair of first wheels 142 .

[0051] More speci fically, the first manipulator 10 comprises a pair of wheel support arms 18 . Each first wheel 142 is mounted on the distal end of a respective wheel support arm 18 .

[0052] The first manipulator 10 further comprises an arm support structure 20 , 22 . Each support arm is hinged to the arm support structure 20 , 22 such as to be rotatable in a hori zontal plane about a vertical oscillation axis . The wheel support arms 18 are further translatable in height along the arm support structure 20 , 22 . Additionally, the arm support structure 20 , 22 istranslatable hori zontally .

[0053] The first manipulator 10 comprises a pair of first electric motors 24 . Each first electric motor 24 is mounted on a respective wheel support arm 18 and is operable such as to rotate a respective first wheel 142 about a wheel rotation axis .

[0054] In one embodiment , the two wheel support arms 18 are hinged to a hori zontal plate 20 that supports two arm motors 30 , each actuatable such as to cause a rotation of the respective wheel support arm 18 on the hori zontal plane .

[0055] Furthermore , for example , due to a crossed rod lever 302 represented in particular in the plan view of Figure 2a, each arm motor 30 , in addition to adj usting the inclination of the respective wheel support arm 18 , is also able to orient the rotation axis of the wheels 142 , i . e . , to cause an angular displacement of the rotation axis of a respective first wheel 142 in a hori zontal plane .

[0056] In an embodiment , the first manipulator 10 further comprises a pair of vertical extension idle pins 26 , each mounted for example on a respective wheel support arm 18 , which act as stops to prevent the sheet metal from slipping out of position during rotation .

[0057] In particular, the rotation axi s of the first wheels142 is oriented for varying the mutual distance of the first wheels such that the rotation axis of the wheels is always oriented substantially radially with respect to the center of the sheet metal 2 .

[0058] In an embodiment , the first motors 24 are mounted coaxially to the rotation axis of the wheels 142 .

[0059] The hori zontal plate 20 is vertically translatable along a vertical plate 22 by means of an electric axis of plate translation 202 .

[0060] This vertical plate 22 is anchored to a carriage 32 which in turn is mounted on a hori zontal guide 34 which allows the carriage 32 to translate , by means of an electric axis of carriage translation 36 , in the direction X towards / away from the press .

[0061] Returning now to the second manipulator 12 , in an embodiment , the third end element 16 consists of an idle wheel 162 . In particular, the rotation axis of this idle wheel 162 is substantially oriented such as to be parallel to the first direction X, i . e . , the direction towards / away from the press 3 .

[0062] More speci fically, in an embodiment, the second manipulator 12 comprises a support crosspiece 40 extending along the first direction X . The idle wheel 162 is mounted on the support crosspiece 40 with the possibility of translating along the support crosspiece40 by means of an electric axis of idle wheel translation42 , for example also mounted on the support crosspiece 40 .

[0063] In turn, the support crosspiece 40 is translatable in height by means of an electric axis of crosspiece translation 44 , along a crosspiece support structure 46 .

[0064] Furthermore , the crosspiece support structure 46 is coupled to a hori zontal guide 48 which allows the crosspiece support structure 46 to translate hori zontally by means of an electric axis for moving the crosspiece support structure 50 along a second direction Y, perpendicular to the first direction X .

[0065] It is evident that the manipulator assembly described above allows the intended obj ects to be achieved .

[0066] Due to the use of electromechanical systems for moving all of the axes , it is possible to obtain much more accurate control of the position of the end support elements of the sheet metal than in any previous manipulator configuration .

[0067] Higher accelerations and speeds may be achieved, which benefits productivity .

[0068] The electric axes have a higher ef ficiency with respect to hydraulic axes and the oil is totally eliminated .

[0069] The area in front of the portal is engaged by the cartesian manipulator, which, being totally evacuable , facilitates loading and unloading operations and the safe tooling of the machine .

[0070] It is possible to make much smaller disc diameters due to the freedom of movements of the manipulators , and, in particular, the possibility of moving the third terminal support element closer to the center of the shaft of the press cylinder .

[0071] The axes of the cartesian manipulator are easily interpolated with those of the first manipulator and move the workpiece as i f the three wheels were in fact integral in those planes that are in contact with the workpiece .

[0072] The position control of the contact point of the idle wheel is automatically compensated as the working angle of the workpiece varies thereby avoiding the risk of loss of the reference with respect to the edge of the disc being processed .

[0073] A considerable improvement of the CNC execution is achieved for greater ease of manipulator control and easier synchroni zation in translation with respect to the molds of the press .

[0074] Furthermore , substantial reduction in the masses of the axes of the manipulator assembly is observed, withrespect , for example , to those manipulators that require guide carriages , a parallelogram, rods and a rod connecting arm to support the wheel .

[0075] In an embodiment , all of the axes are governed by linear guides with very low maintenance .

[0076] Further advantages include a higher axis speed in the absence of premature wear phenomena of the seals of traditional hydraulic actuators , a drastic reduction in noise to operate the axes and, overall , a drastic reduction in the environmental impact of the machinery .

[0077] In order to meet contingent needs , a person skilled in the art may make a number of changes , adaptations , and substitutions of elements with other functionally equivalent ones , to the embodiments of the manipulator assembly according to the invention, without departing from the scope of the following claims . Each of the features described as belonging to a possible embodiment may be obtained independently of the other described embodiments .

Claims

CLAIMS1. A manipulator assembly for manipulating sheet metals to be subjected to forming by means of a press, in particular metal discs to be drawn or curved, where the press forms a portal (3) for accessing the sheet metal forming die on opposite sides, the assembly comprising a first manipulator (10) and a second manipulator (12) , said first and second manipulators being suitable for being positioned facing each other on the opposite sides of the press portal, wherein the first manipulator (10) comprises two first end support elements (14) suitable for forming two sheet metal support points lying on a horizontal plane, said two first end support members (14) being vertically translatable, and wherein the second manipulator (12) is a cartesian manipulator comprising a third end support element (16) suitable for forming a third sheet metal support point.

2. Manipulator assembly according to claim 1, wherein the two first end support elements (14) are movable for varying their mutual distance.

3. Manipulator assembly according to claim 1 or 2, wherein the two first end support elements (14) are horizontally translatable along a first direction (X) towards / away from the press portal.

4. Manipulator assembly according to any one of the preceding claims, wherein the first and second manipulators (10, 12) comprise electromechanical devices for moving the first end elements (14) and the third end element (16) , respectively.

5. Manipulator assembly according to the preceding claim, comprising a control unit for controlling the electromechanical devices, the control unit being programmed to command the electromechanical devices to implement a movement cycle of the sheet metal.

6. Manipulator assembly according to the preceding claim, wherein the control unit is configured to interpolate the position of the third end support element (16) with the position of the first two end support elements (14) such as to make the three support points mutually integral in the contact planes with the sheet metal .

7. Manipulator assembly according to any one of the preceding claims, wherein the first two end support elements (14) consist of a pair of first wheels (142) , the first manipulator (10) comprising:- a pair of wheel support arms (18) , each first wheel (142) being mounted to the distal end of a respective wheel support arm (18) ; an arm support structure (20, 22) , each wheel supportarm (18) being hinged to the arm support structure (20, 22) such as to be rotatable in a horizontal plane about a vertical oscillation axis, the wheel support arms (18) being further translatable in height along the arm support structure (20, 22) , the arm support structure being horizontally translatable; a pair of first electric motors (24) , each first electric motor (24) being mounted to a respective wheel support arm (18) and being actuatable to rotate a respective first wheel (142) about a wheel rotation axis;- a pair of arm motors (30) , each actuatable to cause a rotation of the respective wheel support arm (18) on the horizontal plane and to cause an angular displacement of the rotation axis of a respective first wheel (142) in a horizontal plane.

8. Manipulator assembly according to any one of the preceding claims, wherein the third end support element (16) consists of an idle wheel (162) , the second manipulator (12) comprising:- a support crosspiece (40) extending along the first direction (X) , the idle wheel (162) being mounted to the support crosspiece (40) with the possibility of translation along the support crosspiece;- an electric axis (42) of idle wheel translation mounted to the support crosspiece (40) and actuatable to causethe idle wheel (162) to translate; a crosspiece support structure (46) , the support crosspiece (40) being translatable in height along the crosspiece support structure (46) , the crosspiece support structure (46) being horizontally translatable along a second direction (Y) perpendicular to the first direction (X) .

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