FR2783451A1 - ROBOT FOR HANDLING AN OBJECT - Google Patents

Abstract

Robot for handling an object of the type comprising a fixed base (2) on which is mounted a body (3) produced along a vertical reference axis (XX ') and on which is movably mounted an operating arm (4) s 'extending perpendicularly to said body to which it is subject by means of drive means in rotation of 360 degrees in a horizontal plane and means of drive in vertical displacement corresponding to a stroke of gripping, transport, then removal of an object, according to a U-shaped cycle, characterized in that these means are respectively constituted by a geared motor (6, 7) with automatic play take-up and by a piston (24) with pneumatic linear control also connected in rotation with the geared motor.

Description

ROBOT FOR HANDLING AN OBJECT

  The present invention relates to a robot for handling an object and more particularly a robot provided with an operating arm which can be moved both in rotation in a horizontal plane and linearly in a vertical plane. Robots of this type are known and include a fixed base on which is mounted a body produced along a vertical reference axis and on which is movably mounted an operating arm, equipped with an appropriate gripping means, extending perpendicular to said body to which it is secured, on the one hand by means of 360 rotational drive means in a horizontal plane for obtaining predetermined angular positions of the arm and on the other hand by means of vertical displacement drive corresponding to a grip, transport, and then depositing an object stroke, according to a U-shaped cycle. Currently, the means for driving in rotation and in vertical displacement are produced from

  pneumatic or hydraulic cylinders.

  With regard more particularly to the rotational drive movement, this, when obtained by pneumatic means, has the major drawback of limiting the rotational movement which in fact corresponds to angular sectors whose value is defined by stops

properly positioned.

  This causes a difficulty consisting in having to change the angle values which must be predetermined and necessarily limited in number, because a

  value must correspond to the positioning of a stop.

  In addition, it is necessary to provide as many means of damping the operating arm as there are stops, and the movement from one stop to the other is

relatively slow.

  Finally, such a concept does not make it possible to carry out

fine adjustments.

  With regard to the means for driving in vertical displacement, these, even when they are designed from pneumatic circuits, prove to be of great complexity, which of course translates

  by a significant production cost.

  The object of the present invention is to remedy these various drawbacks by replacing the known pneumatic systems for driving in rotation of an arm with a motorized system and for simplifying the drive system in a new and inventive manner.

  in vertical displacement, even if it remains pneumatic.

  To this end, the invention relates to a robot for handling an object of the type comprising a fixed base on which is mounted a body produced along a vertical reference axis and on which is mounted an operating arm, equipped with a means of appropriate grip, extending perpendicular to said body to which it is secured on the one hand by means of 360 rotation drive means in a horizontal plane for obtaining predetermined angular positions of the arm and on the other hand by by means of vertical displacement drive means corresponding to a grip, transport, and then depositing of an object stroke, according to a U-shaped cycle, characterized in that the means for rotating the arm consist of by an electric motor and a reduction gear, the latter being generally constituted by an endless screw in connection with the motor, via or without an elastic coupling, and rotatably mounted between two bearing elements arranged in line in a cage, to mesh with a reduction wheel with helical teeth also arranged in the cage and whose axis of rotation extends orthogonally to that of the screw and is extended by a control shaft at the end of which said operating arm is fixed. Advantageously, according to another characteristic of the invention, the worm is provided with means for automatically taking up play with respect to the reduction wheel, which are constituted by a screw support element on which the bearings are arranged and which is attached in the cage in a mobile manner on a hinge pin, coming from its bottom and located on the side of the end of the screw in connection with the motor, so as to obtain an angular movement of the support element relative to the cage of o relative to the wheel, for a bearing under permanent stress against the latter, ensuring the elimination of games

existing between them.

  According to another characteristic of the invention, the means for driving the vertical displacement of the operating arm consist of a hollow piston inside which is fixed at its upper end a bearing in which is capable of being driven in rotation an auxiliary shaft perpendicularly extending the arm, and in connection with the control shaft produced as an extension of the worm, so that the hollow piston, the bearing, the auxiliary shaft and the operating arm therein fixed constitute an integral sub-assembly capable of sliding in a fixed concentric hollow body with which the piston locally defines an equally concentric chamber delimited on the one hand transversely by the same walls of the piston and of the body which are of different diameters and on the other hand axially by two fixed lower and upper concentric rings forming stops on which said piston is slidably mounted and between which is likely to be struggled axially a flange of the piston which is substantially the same diameter as the hollow body, said flange being disposed between two inlet and outlet holes for pressurized air connected to a pneumatic installation and opening into said chamber to exert a vertical thrust in one direction or the other on the

  flange of the piston supporting the operating arm.

  According to another characteristic of the invention, rotary connecting means capable of sliding axially are provided between the control shaft produced as an extension of the worm of the reduction gear and the auxiliary shaft extending perpendicularly the operating arm, so as to allow the execution of the U-shaped cycle. The present invention also relates to the characteristics which will emerge during the

  description which will follow, and which should be

  considered in isolation or according to all their

possible technical combinations.

  This description given by way of example not

  limiting, will better understand how the invention can be realized with reference to the accompanying drawings in which: - Figure 1 shows a handling robot, partially in section, equipped with drive means in rotation and drive in vertical movement

according to the invention.

  - Figures 2 and 3 are detail sectional views showing the rotational drive means, respectively in side view and view of

above according to figure 1.

  - Figure 4 is a sectional view showing the vertical displacement drive means according to Figure 1. The handling robot 1, generally designated in Figure 1, comprises a fixed base 2 on which is mounted a body 3, designated also generally, produced along a vertical reference axis XX 'on which is movably mounted an operating arm 4 equipped at its free end with a suitable gripping means (not shown). Said arm (4) extends perpendicularly to the body 3 and is fixed thereto by means of a head 5. The arm 4 is secured to the body 3 on the one hand by means of rotation drive means. 360 in a horizontal plane for obtaining predetermined angular positions of the arm 4, and on the other hand, by means of drive in vertical displacement corresponding to a gripping, transport and then depositing stroke of a object according to a U-shaped cycle. According to a first characteristic of the invention, the means for rotating the arm 4 consist of an electric motor 6 and a reduction gear 7, the latter being generally constituted by an endless screw 8 in connection with the motor 7, whether or not via an elastic coupling 9, and which is rotatably mounted between two elements 10, 11 forming a bearing arranged in line in a cage 12, to mesh with a reduction wheel 13 with teeth helical also disposed in the cage 12 and whose axis of rotation 14 extends orthogonally to that of the screw 8 and is extended by a control shaft 15 at the end of which is fixed said arm

operation 4.

  According to another essential characteristic of the invention, the worm 8 is provided with means for automatically taking up play with respect to the reduction wheel 13, which are constituted by a support element 16 of screw 8 on which the bearings are arranged 10, 11 and which is mounted in the cage 12 in a mobile manner on a hinge pin 17, coming from its bottom 16a and situated on the side of the end of the screw 8 in connection with the motor 7. In this way, there is obtained an angular movement of the support element 16 relative to the cage 12 o relative to the wheel 13, for a bearing under permanent stress against the latter, ensuring the removal of games

existing between them.

  According to another characteristic of the invention, the permanent support under stress of the screw 8 against the wheel 13 is obtained by means of an elastic return member 18, interposed between a fixed point 19 of the cage 12 and part 20 of the element

  articulated support 16, opposite its articulation 17.

  In fact and preferably, the support element 16 is obtained from a U-shaped structure, the horizontal bottom branch 16a of which is pierced with a hole made under one of its vertical branches 16b and capable of receiving the hinge pin 17 from the bottom of the cage 12, the vertical branches 16b and 16c of the same U comprising housings made opposite for

receive the bearings 10, 11.

  These bearings 10 and 11 are advantageously constituted by angular contact ball bearings, and it is the same for the axis 15 of the reduction wheel 13 which is orthogonal to the worm 8, as described above. Indeed, the aforementioned axis 15 is supported by two bearings 21 and 22, in fact also angular contact bearings which are housed in corresponding housings. A plug 23 pushing on the outer rings of these to

make up for all the mounting games.

  According to another characteristic of the invention, the stressing force of the worm 8 on the reduction wheel 13 is at least reduced during the rotation phase allowing the arm 4 to go from an angular position to another, by a means exerting a force contrary to that of the elastic return member 18 acting on the U-shaped support element 16 of the worm 8 to temporarily remove the stress exerted by said member

elastic return 18.

  This has the advantage of relieving the motor 6 during the rotation phase of the arm, therefore avoiding an oversizing of this motor which would be due to the stress, in fact during a phase where this is unnecessary. In addition, this reduces the friction between the screw 8 and the wheel 13, thus avoiding

  premature wear of these elements.

  According to another characteristic of the invention, the means exerting a force contrary to the elastic return member 18 of the worm 8 consists of an electromagnet (not shown) acting in attraction on the U-shaped support element 16 in a direction opposite to that of the elastic return member 18. It is also possible to act on the force of the electromagnet to obtain a pressing force between the screw 8 and the wheel 13 which is programmable as a function of the

precision to be obtained.

  It should also be noted that the U-shaped support element 16 is adjusted bold between the upper and lower wall of the cage 12 of the reduction gear, so as to eliminate any degree of axial freedom and to keep the degree of freedom in rotation around the axis

hinge 17.

  According to another characteristic of the invention, the means for driving in vertical displacement of the operating arm 4 consist of a hollow piston 24 inside which is fixed at its upper end a bearing 25 in which is likely to be driven in rotation an auxiliary shaft 26 perpendicularly extending the arm 4, and in connection with the control shaft 15 made in extension of the worm 8. The hollow piston 24, the bearing 25, the auxiliary shaft 26 and the arm maneuver 4 which is attached to it thus constitute an integral sub-assembly capable of sliding in a fixed concentric hollow body 27 with which the piston 24 locally defines a chamber 50 also concentrically delimited on the one hand transversely by the same walls of the piston 24 and of the body 27 which are of different diameters and on the other hand axially by two concentric rings, one lower 29 of which is movable with the piston 24 and plays a role the scraper in room 50

  and the other upper 28 being fixed and forming a stop.

  In fact, the piston 24 is slidably mounted on the fixed ring 28 and on another fixed ring 51 situated under the movable scraper ring 29. A flange 30 is produced on the piston 24 and is substantially the same diameter as the hollow body 27. Said flange 30 is therefore capable of struggling axially in the chamber and is arranged between two inlet and outlet holes for pressurized air 31, 32 connected to a pneumatic installation and opening into said chamber 50 to exert a vertical thrust in one way or the other on the flange 30 of the piston 24

maneuvering arm carrier 4.

  Preferably, the rings 28, 29 and 51 are constituted by quadrilobe seals ensuring

  also the sealing of the chamber 50.

  The hollow body 27 further comprises two self-lubricating guide rings 33, 34 fixedly disposed on said body beyond each of the abutments 28, 29 of the flange 30 of the piston 24. Furthermore, means 35 for rotating and axially sliding connection are provided between the control shaft 15 produced as an extension of the worm gear 8 of the reduction gear and the auxiliary shaft 26 extending

  perpendicularly the operating arm 4.

  These means consist on the one hand of a first ring 36 which is axially fixed but integral in rotation with one end of the control shaft 15 produced as an extension of the worm 8 of the reduction gear, and on the other hand by a second ring 37 secured both in rotation and in axial displacement of a free end of the auxiliary shaft 26 opposite the operating arm 4 that it extends. Said second ring 37 has two diametrically opposite holes 38, 39 with which two pins freely cooperate, 41 from the first ring 36 on which the holes 38, 39 of the second ring 37 are capable of sliding during axial displacement of the piston 24 o of the auxiliary shaft 26 on which it is fixed or to be driven in rotation by the same

  first ring 36 by action of the gear motor.

Claims (10)

  1. Robot for handling an object of the type comprising a fixed base (2) on which is mounted a body (3) produced along a vertical reference axis (XX ') and on which is movable an operating arm (4 ) equipped with a suitable gripping means extending to said body to which it is secured, on the one hand by means of 360 rotation drive means in a horizontal plane for obtaining predetermined angular positions of the arm and on the other hand by means of drive for vertical displacement corresponding to a grip, transport, and then depositing of an object, according to a U-shaped cycle, characterized in that the drive means in rotation of the arm (4) are constituted by an electric motor (6) and a reduction gear (7), the latter being generally constituted by a worm (8) in connection with the motor (7), via or not of an elastic coupling (9), and rotatably mounted between e two elements (10, 11) forming a bearing arranged in line in a cage (12), to mesh with a reduction wheel (13) with helical teeth also arranged in the cage (12) and whose axis of rotation (14 ) extends orthogonally to that of the screw (8) and is extended by a control shaft (15) at the end of which is fixed said operating arm (4).   2. Robot according to claim 1, characterized in that the worm (8) is provided with means for automatically taking up play with respect to the reduction wheel (13), which are constituted by a support element (16) of screw (8) on which the bearings (10, 11) are arranged and which is attached in the cage (12) in a mobile manner on a hinge pin (17), coming from its bottom (16a) and located on the side of the end of the screw (8) in connection with the motor (7), so as to obtain an angular movement of the support element (16) relative to the cage (12) o relative to the wheel ( 13), for a permanent restraint against it, ensuring the removal of existing games between them.   3. Robot according to claim 2, characterized in that the permanent support under stress of the screw (8) against the wheel (13) is obtained by means of an elastic return member (18), interposed between a fixed point (19) of the cage (12) and a part (20) of the articulated support element (16), opposite its articulation (17).   4. Robot according to claim 2 or 3, characterized in that the support element (16) is obtained from a U-shaped structure, the horizontal bottom branch (16a) of which is pierced with a hole made under a of its vertical branches (16b) and capable of receiving the hinge pin (17) coming from the bottom of the cage (12), the vertical branches (16b and 16c) of the same U comprising housings made opposite for receive them bearings (10, 11).   5. Robot according to claim 3 or 4, characterized in that the stressing force of the worm (8) on the reduction wheel (13) is at least reduced during the rotation phase allowing the arm (4) to go from one angular position to another, by a means exerting a force contrary to that of the elastic return member (18) acting on the U-shaped support element (16) of the worm (8) to temporarily remove the constraint exerted by   said elastic return member (18).   6. Robot according to claim 5, characterized in that the means exerting a force contrary to the elastic return member (18) of the worm (8) consists of an electromagnet (not shown) acting in attraction on the U-shaped support member (16) in a direction opposite to that of the elastic return (18).   7. Robot according to claim 1, characterized in that the drive means for vertical displacement of the operating arm (4) consist of a hollow piston (24) inside which is fixed at its upper end a bearing ( 25) in which an auxiliary shaft (26) which is perpendicularly extending the arm (4) is capable of being rotated, and in connection with the control shaft (15) produced as an extension of the worm (8), so that the hollow piston (24), the bearing (25), the auxiliary shaft (26) and the operating arm (4) which is attached to it constitute an integral sub-assembly capable of sliding in a concentric hollow body fixed (27) with which the piston (24) locally defines a chamber (50) also concentric delimited on the one hand transversely by the same walls of the piston (24) and of the body (27) which are of different diameters and other starts axially by two concentric rings, one of which lower (28) is movable with the piston (24) and plays a scraper role in the chamber (50) and the other (29) of which is fixed and forms an abutment on said piston (24) which is slidably mounted on said fixed ring (28) and another fixed ring (51) located under the movable scraper ring (29), so that a collar (30) produced on the piston (24), substantially of the same diameter as the body hollow (27), or capable of struggling axially in the chamber (50) between two inlet and outlet holes for pressurized air (31, 32) connected to a pneumatic installation and opening into said chamber (28) for exert a vertical push in one direction or the other on the flange (30) of the piston (24) carrying the arm operation (4).   8. Robot according to claim 7, characterized in that the hollow body (27) further comprises two self-lubricating guide rings (33, 34) fixedly disposed on said body beyond each of the stops (28, 29) flange (30) of the piston (24).   9. Robot according to any one of claims 1   8, characterized in that means (35) for rotary connection and capable of sliding axially are provided between the control shaft (15) produced as an extension of the worm (8) of the reduction gear and the auxiliary shaft ( 26) extending perpendicularly the operating arm (4).   10. Robot according to claim 9, characterized in that these means consist on the one hand by a first ring (36) fixed axially but integral in rotation with one end of the control shaft (15) produced as an extension of the worm (8) of the reducer, and on the other hand by a second ring (37) integral both in rotation and in axial displacement of a free end of the auxiliary shaft (26) opposite the operating arm ( 4) that it extends, said second ring (37) comprising two diametrically opposite holes (38, 39) with which cooperate two pins (40, 41) coming from the first ring (36) on which the holes are likely to slide ( 38, 39) of the second ring (37) during an axial displacement of the piston (24) o of the auxiliary shaft (26) on which it is fixed or of being rotated by the first ring ( 36) by action of the gearmotor.