Patent GB-1331499-A (GB)
Title: Apparatus and method of searching for locating and engaging  an article
IPC: B25J13/08
Filed: 1970-09-24
Abstract: 1331499 Workpiece transferring AMERICAN ASSOCIATED CYBERNETICS Inc 24 Sept 1970 [25 Sept 1969 20 Aug 1970] 45434/70 Heading B3B [Also in Divisions B8 and G4] Apparatus capable of searching for, locating and engaging an article, e.g. a workpiece during a drilling operation, comprises a frame, an article engaging head 126 movablly mounted on said frame for movement along at least first and second orthogonal axes, drive means for moving said article engaging head along the first and second axes, position sensor means providing a first signal representative of the position of the article engaging head along the first axis, an article responsive sensor mounted on the head and providing another signal when the article responsive means detects an article when said head is driven by the drive means along the second axis, control means for controlling the drive means in response to said first and said other signal, and actuating means for actuating said article engaging head to engage the article. The position sensor means operative along, e.g. a horizontal axis, comprises a row of sensors 100 that can be selectively energized to be actuated by an actuator 102 movable with the horizontal movement of the head. The head 126 may include a photometric scanning sensor 932 for responding to an article within its range and stopping the movement of the head. The sensor 932 comprises a spotlight meter having an optical field of 3 degrees, or more, and which is responsive to light reflected from the article. The apparatus is programme controlled. In the embodiment described the apparatus comprises a machine having a base, which may be portable on wheels, on which a laterally movable carriage 24 is driven by a motor 30 and lead screw 44. Sensor means 56 control the speed and position of the carriage 24. On the carriage 24 is mounted a slide 60 movable by means of a motor 80 and lead screw 84 drive. Sensors 100 and actuator 102 control the speed and position of the slide 60. At the end of a channel member 72, 74 carried by the slide 60 is a vertical rack member 110 carrying the head 126. A motor 122 drives a pinion 116 to raise and lower the head 126. Switches 144, 146 and sensors 150, 148 control the vertical movement of the head 126. Automatic control.-A programme is set up by a series of detents on a drum rotatable to actuate a series of control switches. The function of the programme includes selectively energizing the position sensors, e.g. sensors 100, to fix a stop position, and a position prior to the stop position where deceleration of the moving part starts, and to select resistances in the drive motor circuits to select a feed speed. The sensors may be capacitance or inductance responsive, or be photo-cells. The movement of the head 126 in the three mutually perpendicular axes may take place simultaneously or consecutively. The head 126 may comprise a pressure cylinder operated gripping device on which are mounted sensors for controlling movement along the three axes, and the article responsive sensor 932. The photometric scanning device 932 is selfadjusting to ambient light conditions. After a signal is produced, and acted upon, by a reflection from an article, a control circuit (Fig. 10, not shown) operates to cancel the signal so that only the initial movement into the optical field produces a signal. This signal is passed to a trigger circuit which passes out a symmetrical square wave output to operate solenoid switches of the control circuit. The duration of the square wave output is proportional to the amount of light reflected so articles can be distinguished by their reflective characteristics or by their colour by counting the number of square waves.