FR2548941A1 - ROBOT WITH ARM ELBOW FOR CUTTING - Google Patents

Abstract

A.ROBOT WITH ELBOW ARM FOR CUTTING, ESPECIALLY FOR CUTTING USING AN AUTOGENOUS OR METAL PLASMA TORCH, ROBOT WITH AN ELBOW ARM AND A ROTATING JOINT FIXED AT THE FREE END OF THE ELBOW ARM. B.ROBOT CHARACTERIZED IN THAT A CUTTING TORCH 32 WITH THE HEIGHT CONTROL 55 OF THE CORRESPONDING TORCH ARE ATTACHED TO THE ROTATING JOINT 18. C. THE INVENTION RELATES TO ROBOTS ESPECIALLY WELDING.

Description

"Angle robot for cutting metal with a blowtorch

autogenous or plasma ".

  The invention relates to a robot arm for cutting especially for cutting with an autogenous torch or plasma metal, robot comprising an angled arm and a rotary joint attached to the free end of the folding arm. Angled robots are used to automate production operations and constitute a

  necessary condition to permanently increase the yield.

  Angle-arm robots for cutting, in particular for cutting with the aid of an autogenous blowtorch or a metal plasma torch, and to which is associated a program unit, for guiding the torch, automatically along an predetermined trajectory, are increasingly used in recent years for the machining of t 8 (Advertising Document Messer Griesheim No. 32 3023, 1981, Eurobot 3 and Advertising Document Messer Griesheim No. 32 3020, 1983, Eurobot - W). The trajectory of the movement of the known bent-arm robot, that is to say, the tracing of the cut by a point-by-point path, is programmed by hand at the different points of the trajectory. program, we put the different axes

2548941.

  in the corresponding position and by pressing the program key, they are stored in the robot control. In autogenous torch or plasma cutting machines, the cutting torch must be described by means of a command. of trajectory, a trajectory curved in space, arbitrary, with great precision

of repetition.

  When the curved trajectory in space has a non-regular pattern or because of the effect of heat on the workpiece, there are variations in the height of the workpiece, the programming of the irregularly curved path is on the one hand very costly, even impossible, because it is necessary to go step by step a very

  a large number of points of the trajectory, for example it is necessary to record up to 2,000 points of the trajectory.

  On the other hand, variations in the height of the part by drawing during the cutting are not taken into account by the program control.

  erroneous cutting with the aid of the autogenous torch or plasma.

  It is an object of this invention to simplify three-dimensional cutting trajectory programming using the program unit described above.

  The present invention also aims to automatically compensate for the variations in height of the parts by stretching during cutting, so that the cutting torch is guided to "the correct height" that is to say at a constant distance beyond- In this case, the "correct height" is at least from time to time different from the "programmed height". For this purpose, the invention relates to a robot of the above type, characterized in that a torch of

  cutting with the torch height control corres-

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  is attached to the rotary joint.

  The advantages of the invention lie essentially in the fact that in a simple manner, by the arrangement of the cutting torch height control on the rotary joint of the right-angle robot, the number of trajectory points at command since the differences in height of the path are no longer to be taken into account separately and that furthermore the height variations are compensated by stretching Thanks to the installation according to the invention, it is possible advantageously with recorded routes in two dimensions, to cut pieces having a three-dimensional shape, and whose height is automatically maintained at a constant level. In particular, to implement these advantages without the need for a costly programming unit or program, a motorized trolley is provided between the rotating joint of the folding arm robot and the

cutting torch.

  An embodiment of the invention will be described in more detail with the aid of the accompanying drawings, in which:

  Figure 1 is a perspective view of the robot with crank arm according to the invention.

  FIG. 2 is an enlarged view of the components, the rotary joint, the cutting torch and the torch height control.

  FIG. 1 shows a boom robot with five degrees of freedom generally bearing the reference. The five degrees of freedom of the folding arm robot 10 are produced by the rotation unit 12, the arms 14, 16.

  as well as the rotary joint 18.

  The driving of the controlled axes 12, 14, 35 16 is ensured by servomotors 20, 22, 24.

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  rotary assembly 18 is driven by a motor, not shown

  in detail, allowing to turn this rotary joint 18 of 180 as well as 300.

  According to an exemplary embodiment of the invention, there is provided a carriage 26 at the rotary joint 18, which carriage consists of a guide piece 28 attached to the rotary joint 18 and a piece of

  carriage 30 with linear movement on the guide piece 28.

  A ball-and-socket rotary spindle, not shown in detail, is mounted on the guide piece 28, which pin serves to guide the carriage-shaped part. The spindle rotational pin is driven by

  a motor provided in the guide piece 28.

  As shown in FIG. 2, the cutting torch 32 with a tilting fork-shaped member 34 is provided on the carriage-shaped part 30.

  Between the flanks 36, 38 of the fork-shaped part 34 is a bearing block not shown in detail, which is connected to the sidewalls 36, 38 of the fork-shaped part 34 by a shaft The shaft is mounted The lower face of the bearing block constitutes a fastening plate screwed onto the trolley-shaped portion. The front face of the fork-shaped part 34 is aligned with holes in the sidewalls 36, 38 as well as on a hole in the block. is made in the form of a torch holder An autogenous cutting torch 32 is fixed in the bore 42 of the torch holder 40, the torch being fed by gas supply pipes and

oxygen 44, 46.

  A control box 48 is attached to one side of the fork member 34; the control and oscillation circuit of the capacitive height control 55 of the torch is housed in the housing 48. The electrical supply of the control and oscillation circuit 35 is provided by the lines 50 of the housing side of the housing 2548941). control 48 facing the nozzle 52 of the torch is a capacitive sensor element 54 The capacitive sensor element 54 consists of a sensor 56 provided in the immediate vicinity of the nozzle 32 of the torch; the sensor 56 is connected to the control box 48 by a fixing rod 58. On the side of the control box 48 opposite the torch holder 40 is connected an air supply 64 which serves for the cooling of the electronic components /

  electrical oscillating circuit and capacitive adjustment.

  On the same side of the carriage 26, a feed 66 is attached to the trolley portion 30, which feeds the air via a copper tube 68 for the interval between the sensor 56 and the workpiece. air in this intermediate volume, air whose pressure 15 is adjusted in any way by a valve 70, it ensures firstly the cooling of the sensor 56 and secondly maintains a constant atmosphere between the element of capacitive sensor 54 and the room so that the gases of

  Combustion as well as smoke etc. do not influence the capacitance between the sensor 56 and the workpiece.

  When the capacitive pitch control 56 of the torch determines a deviation of the height of the workpiece from the programmed height and / or the height set by the torch height control 55, the pitch signal controls the motor of the carriage 26 and the carriage 26, whose travel preferably corresponds to 50 mm, to move the torch 32 correspondingly to the constant distance set by the control of

torch height 55.

  In order to arrive at a correct programming, the carriage 26 is commanded so that during programming it is in a middle position. This is thus ensured for a posteriori adjustment during cutting in an area of between + 20 mm and 20 mm. At the end of a cut, the carriage 26 automatically returns to the upper position. For a new part, the torch is guided from this upper position to the workpiece and

the sensor 56 adjusts the height.

  It is of course also possible to control the motorized carriage indirectly through the torch height control 55 by providing the height signals to the robot control to control the

motorized trolley 26.

  It is furthermore possible to introduce directly into the robot control the height variations detected by the torch height control 55, and

  which displaces the entire bent arm robot and thus the cutting torch to adjust it to the desired height In this case, the motorized carriage 26 can be removed from the rotary joint 18.

R E V E N D L C A T IO N S

  1) Robot with an angled arm for cutting, in particular for cutting with the aid of an autogenous or metal plasma torch, robot comprising an angled arm and a rotary joint fixed to the free end of the robot angled arm characterized in that a cutting torch (32) with the corresponding torch height control (55) is attached to the joint

rotary (18).

  2) An elbow robot according to claim 1, characterized in that a motorized carriage (26) is fixed between the rotary joint (18) and the cutting torch (32) with the corresponding control

torch height (55).

  3) An elbow arm according to any one of claims 1 or 2, characterized in that

  the height control (55) of the torch is connected

  directly to a robot control.

  4) Robot arm according to claim 2, characterized in that the output signals of the height control (55) of the torch are susceptible

  to be supplied to the motor of the carriage (26).

   An elbow robot according to any one of claims 1 to 4, characterized in that the torch height control (55) is a control of

capacitive height.

  6) Robot with crank arm according to any one of claims 1 to 5, characterized in that

  air supply (64, 66) for cooling the control box (48) and the sensor (56) and for maintaining a constant atmosphere between the sensor (56) and the workpiece is associated with the height control (55) torch.