Title of Invention

"A GANTRY ROBOT"

Abstract

A gantry robot comprising a manipulator having a gripper secured therewith being mounted on a pair girders secured at the top ends of the columns, an AC servo motor being mounted onto said column such that to provide motions to said manipulator and gripper, a controller is provided with a teach box facility for controlling the operation of said manipulator and gripper, means are provided for external interlocks for system integration, safety in operation and process specific coordination.

Full Text

This invention relates to a Gantry Robot. The manufacturing activities in an industry involves metal forming such as bending and rolling, metal cutting such as lathe, milling and boring. Fabrication such as various types of welding. Material handling such as loading and unloading of materials and components to a machine is done by the operator himself if it is within his capacity. Heavier components are handled by the operator with the assistance of a helper. Further heavier components are handled by providing a manually operated mechanical or an electrical hoist to each such machine. Sometime the overhead crane of the shop is used for loading and unloading of materials from machines. In the past, such machines were multipurpose, manual and was very slow. So time taken including handling of material was not a matter of concern. But now with the advent of operations research and its application in manufacturing Industries for improvement of productivity it became very important to reduce labour and time wasted in handling material. Coupled with this, with the development of computer saw its application in metal working machines, particularly special purpose machine adapted to produce a single job respectively in the form of CNC (Computer Numerical Control). Such machines became very sophisticated in terms of-higher productivity and was very costly. Whereas the entire operations are done automatically what is still being done manually is loading positioning and unloading of the material or components in such machines. Thus the machines are kept idle for considerable time and is an area of concern. For this purpose and for loading, unloading of job to a machine and for movement from machine to storage area an overhead electric gantry crane is used. These cranes have three axis movement/ X, Y and Z direction and all movements are operated with a motor. The crane is operated manually by an operator from a cab at one end of the crane. In very exceptional case, as in a hazardous process shop, the crane can have dual control with remote operation through radio. These cranes are not very accurate and cannot position jobs in machines for automatic operation. Invariably the operator has to adjust and set the job manually which takes considerable time. Therefore an object of the present invention is to propose a gantry robot for handling of materials to process in the processing machines particularly CNC machines to reduce idle time and increase in tool engagement time. Another object of the present invention is to propose a gantry robot for CNC machine which is exclusive and integral with the machine. Thus the other common handling facilities like overhead cranes etc. are free According to this invention there is provided a gantry robot comprising a manipulator having a gripper secured therewith being mounted on a pair girders secured at the top ends of the columns, an AC servo motor being mounted onto said column such that to provide motions to said manipulator and gripper, a controller is provided with a teach box facility for controlling the operation of said manipulator and gripper, means are provided for external interlocks for system integration, safety in operation and process specific coordination. In accordance with this invention the Gantry Robot has four axis manipulator provided with hydraulic gripper secured with the manipulator. AC servo motors having input/output conveyors are provided for providing motion to the manipulator and hydraulic gripper. The controller is provided with a teach box facility to control the movements of the manipulator and the gripper. Means are provided for external interlocking for system integration, safety in operation and process specific coordination. The manipulator is provided such that to have motion in the X-axis and Y-axis so as to cover the area of the work center. It has a Z traverse to lift/pick the work piece to do respective job with consistent and improved productivity. Yet another object of the present invention is to provide a gantry robot for offering user friendly operator interface, programming language and user file handling under the Gross (Gantry robot operating system Software) resident in an Industrial PC and closed loop position control of AC servo motors under the axis controllers which is a reliable and predictable throughput. Still another object of the present invention is to provide an automated system of loading, positioning and unloading of work piece on machines which relieves labour fatigue considerably and increases machine utilization and is very precision in positioning jobs on the machine. and place them on the work centre or discharge station. The Z slide carries the gripper for automatic loading and unloading of work pieces. The gripper is mounted on a rotary mounting which facilitate indexing to keep the work piece in desired orientation. The input and output chain conveyors are provided for loading the work piece at a define location and for moving the work piece away from the work position. The Gantry Robot according to a preferred embodiment is herein described and illustrated in the accompanying drawings wherein: Fig.l shows the plan view of the Gantry Robot with a CNC machine located under the Gantry Robot. Fig. 2 shows the plan view of the manipulator along the X-axis and Y-axis Fig.3 shows the manipulator driving system along Z-axis Fig.4 shows the rotary axis assembly Fig. 5 shows the plan view of the gripper. Fig.6&7 shows the conveyor assembly. Fig.8 - shows the schematic of servo control means and Fig.9 shows the schematic of the controller. Referring to the drawings particularly Fig.l the Gantry Robot has four columns 5 for supporting girders 10 at two sides longitudinally. Tie beams 5A are provided between said girders and at the other sides of said columns for securing said girders with each other. A gripper 6 with a rotar axis 5 is mounted on the girders 10 slidably in X, Y and Z directions. Input conveyor 7 and output conveyor 8 are provided along the length of the girders for providing the work piece on the working station of the CNC machine 1 and for removing the work piece from the work station of the machine 1 provided with a pellet 2, machine controller 4 and Robot Controller 3. Reference is now made to Fig.2 the manipulator assembly comprises two girders 10 mobnted on the column 5 at the sides longitudinally, Ti beams 5A are provided between said girders and near the column 5 to secure the girders 10 with each other at both the sides thereof. Pulley assemblies 13 with pulleys 11 are provided at top end of. each column such that to drive the belts 12 provided for driving the X slide 17 of the manipulator. LM guides 14 are provided on the same side at which the girders 10 are provided for supporting LM blocks 15 which moves in X direction having a X slide 17 mounted thereon. A servo motor M1 is provided for driving the pulley assembly 13 having conveyor belts 12 provided therewith. A Y slide 18 is mounted on the guides 18A which are supported on the LM blocks 15. The Y slide 18 is adapted to be moved by means of a pulley assembly 13A having a belt 12A provided therewith in the Y direction. A motor M2 is provided for driving pulley assembly 13A. Z slide 19 with a motor M4, is secured with the Y slide 18 for providing movement to the Z slide 19 in the vertical direction. A motor M3 is provided for the rotary axis movement to the manipulator for placing the work piece on the working station of the machine at the desired position, As shown in Fig.3 the Z-axis assembly to provide movement to said gripper in the vertical direction comprises a servo motor M to driving with screw means 21 through a driving belt 20. The Z slide 19 slides over linear motion (LM) guides 14A through LM blocks ISA. Further the rotary axis assembly as shown in Fig.4 comprises crossed roller bearings 23 of the Z slide and a rotary joint flenge 22 provided for imparting rotary movement to the Z slide 19. Reference is now made to Fig.5 the gripper comprises jaws 24 secured with dovetail slides 25 which is adapted to be slided through a hydraulic cylinder 27. Reference is now made to Figures 6 & 7 wherein the conveyor belt assembly is shown. The conveyor belt assembly comprises a slats and chain assembly 35 mounted over a driven sprockets/roller 31 and a drive sprocket/roller 28. The driven and drive sprockets 31 & 28 are mounted over a frame 32. A motor 30 is provided at the bottom of frame 32 and is connected with the drive sprockets/roller 28 through a gear box 29. A tray 33 is provided at one side end of the conveyor and a hydraulic cylinder 34 is provided at the other side of said end of the conveyor assembly. Reference is now made to Fig.8. wherein the servo control system is shown, The servo control system comprises a speed controller 36 connected to a current controller 37 having a actual current means 38 connected to the input terminal of the current controller 37. The output of the current controller 37 is connected to the pulse width modulator 39 provided for converting the continuous analog value in to the binary signal. The output of the pulse-width modulator 39 is connected to a pulse drive circuit 40 of co-ordinator 41. The co-ordinator 41 comprises a pulse drive circuit 40 secured with a tacho-voltage 42 having a current meter 38 connected therewith. The outputs of inverter 42 are connected to an AC synchronous motor 43 which is connected to a tacho-generator 44. The tacho-generator is connected to a shaft encoder 45. Further the output of invertor 42 are connected to a current device 38. Similarly the tachogenerator 44 and shaft encoder 45 are connected to a tachovoltage of the coordinator 41. The output of tachovoltage is connected to input speed controller 36. The pulse/pause ratio of the signal is proportional to the amplitude of the input signal. The pulse width modulated set point signal drives the invertor which produces a voltage proportional to the set point. The mean value of which is determined by the pulse/pause ratio. In AC feed drives, the function of the electromechanical commutation is performed by an electronic commutator, and thus the power section of a transister pulse with modulator, invertor is driven by the shaft angle encoder signals. The actual speed value is provided by a brushless AC tachogenerator. Reference is now made to Fig.9 the Robot Controller comprises a PC/AT Robot operating system 46 connected with a micro-processor based axis controller 47. The Robot operating system (ROS) is provided for Robot controller front end interface and the microprocess based axis controller is provided for motor controllers for realising the closed loop position control for individual motors. The motion of the manipulator are driven by AC servo motors M1, M2, M3 and M . The controller is provided with teach box facility and a programming language with easy to use syntax for use programming facilities for external interlocks for system integration, safety inoperation/ and a process specific coordination. The operator commands written in Robot programming language are interpreted by the controller to generate individual axis control. The axis control then carjsry out the positioning function in closed loop operation by monitoring the position of using incremental encoder feed back facility. Gantry Robot operating system software (GROSS) is the enviornment under which the gantry robot functions are available to the operator offering flexibility, easy to use language and features to integrate the robot with existing work enviornments. The robot has several safety features like motor overload protection, excess heating of motors, limit switch for end limits, power failure etc. causing generation of. emergency condition and holding the manipulator static in the event of above failures. WE CLAIM: 1. A gantry robot comprising a manipulator having a gripper secured therewith being mounted on a pair girders secured at the top ends of the columns, an AC servo motor being mounted onto said column such that to provide motions to said manipulator and gripper, a controller is provided with a teach box facility for controlling the operation of said manipulator and gripper, means are provided for external interlocks for system integration, safety in operation and process specific coordination. 2. A gantry robot as claimed in claim 1 wherein said manipulator comprises an X-slide are mounted slidably on linear motion (LM) guides, a Y-slide is supported slidably on another set of linear motion guides being mounted on said linear motion guides, a Z-slide is slidably supported on Y-slide, pulley assemblies are provided near the top end of the columns for providing movement to said X-slide in the X-direction. 3. A gantry robot as claimed in claim 2 wherein pulley assemblies are secured with said X-slide being provided for providing motion so said Y-slide mounted on said X-slide slidably. 4. A gantry robot as claimed in claim 2 wherein said linear motion guides comprises a pair of guide rods being mounted over the girders mounted on a plurality of columns at either sides, tie beams are secured with said girders at either ends thereof for securing said girders with each other. 5. A gantry robot as claimed in claim 2 wherein said X slide is supported on said linear motion guide by means of linear motion blocks supported slidably on said linear motion guides, 6. A gantry robot as claimed in claim 1 wherein said controller connected to a current controller being connected with pulse-width modulator, the outputs of the pulse-width modulator are connected to a coordinator which is connected to an invertor having an AC synchronous motor, the outputs of said AC motor are connected to the tachogenerator which is connected to a shaft controller. 7. A gantry robot as claimed in claim 6 wherein said coordinator comprises a pulse drive circuit having a current means and tachovoltage means connected therewith, the current menas are adapted to be connected with the output of said invertor and the output of said current means is connected to the input of said current controller, the outputs of tachogenerator and shaft encoder are connected to tachovoltage of said coordinator, the output of said tachovoltage is connected to the input of said speed controller, 8. A gantry robot substantially as herein described and illustrated in the drawings.

Documents:

571-del-1995-abstract.pdf

571-del-1995-claims.pdf

571-del-1995-correspondence-others.pdf

571-del-1995-correspondence-po.pdf

571-del-1995-description (complete).pdf

571-del-1995-drawings.pdf

571-del-1995-form-1.pdf

571-del-1995-form-2.pdf

571-del-1995-form-3.pdf

571-del-1995-form-4.pdf

571-del-1995-form-5.pdf

571-del-1995-form-6.pdf

571-del-1995-form-9.pdf

571-del-1995-gpa.pdf