Patent GB-1483360-A (GB)
Title: Apparatus for transferring a rectangular or generally elliptical viewing panel to a grinding station and for grinding the panel
IPC: H01J9/46
Filed: 1974-11-05
Abstract: 1483360 Grinding CORNING GLASS WORKS 5 Nov 1974 [5 Nov 1973] 47763/74 Heading B3D Apparatus for transferring a rectangular or generally elliptical viewing panel P for a cathode-ray tube or television picture tube between a panel receiving station and a grinding station and for flat grinding of an annular sealing edge at the station comprises a platform 30 and jig 33 for supporting the panel at the receiving station, a rotatable vacuum chuck assembly VC and pivoting transfer arm 39 for holding and transferring the picked-up panel and rotating it not the grinding station, an even number of flat motor-driven grinding wheels 21, ... 24 lying in a common plane, the centres of rotation of the wheels being radially symmetrically disposed about an axial centre line A-A, and an electrical power source and control circuit for operating the apparatus in the proper sequence. As described, the apparatus has a tub 14 carried by a support 11 from a base 12, the tub having four supports 15 for bushes 16 in which are shafts 19 rotated by motors M1, M2. The upper ends of the shafts carry grinding discs 21, ... 24, the operative surfaces of which lie in a common plane. Adjacent grinding discs rotate in opposite directions, and the discs are equally positioned about the axis A-A. Slurry supplied to the discs falls to the sloping bottom of the tub and is collected by a drain pipe 14c. The platform 30 is secured by arms 31, 32 to the base and has an upper surface 30c on which the panel can be positioned by a jig 33 with its centre at a point B. An arm 39 is mounted on a shaft 35 rotatable in a bearing 36 and can be swung by operation of a piston-andcylinder device HIDC so that its end is aligned with the position B at the panel receiving station or with a position C aligned with the axis A-A at the grinding station. The arm 39 carries a motor H.M. having an output shaft connected by a rod 106 to a sleeve 11D, in turn connected to a shaft 61, the lower end of which carries the vacuum chuck VC having an annular cover 130 held by clamping bands 131, 132. The shaft 61 is keyed to a sleeve 58 which is rotatable in a housing 56 secured to the arm 39. The shaft 61 extends through a rotary union RU by which a vacuum source can be connected to a bore 61c in shaft 61 leading to the vacuum chuck. A quadrant 85a extends from an annular member 85 rotatably mounted on shaft 61. A rod 90 is secured to the quadrant and a boss 92 on the rotary union RU and is slidable in bus-bars 94, 95 in a part 96 integral with the housing 56. A cylinder-and-piston device HUDC carried by the arm 39 has its rod PR2 secured to the quadrant 85. In operation, a panel P is positioned on the support 30 and a push button is pressed to start a timer of a control circuit having a number of switches operated in sequence. The motors for rotating the grinding discs are energized and, with the arm 39 positioned so that the vacuum chuck is above position B at the receiving station, cylinder HUDC is actuated to extend its rod PR2 and lower the drive shaft 61 so that the chuck engages and holds the panel. The operation of the cylinder is then reversed to raise the panel and cylinder HIOC is actuated to swing arm 39 to position the panel at point C wherein motor HM is energized to rotate shaft 61 and cylinder HUDC is again actuated to lower the shaft 61 so that the edge of the skirt portion of the panel is engaged by the grinding wheels for a predetermined time. Thereafter the panel is returned to the receiving platform 30 and released by the chuck.