Patent GB-1484485-A (GB)
Title: Apparatus for bevelling the panels or funnels of television picture tubes
IPC: B24B9/12
Filed: 1974-12-04
Abstract: 1484485 Grinding bevels CORNING GLASS WORKS 4 Dec 1974 [7 Dec 1973] 52422/74 Heading B3D An apparatus for bevelling the sealing edge of substantially rectangular or elliptical viewing panels or funnels of television picture tubes P comprises a workpiece support VC having a shaft 61 rotated by a first rotary motor HM and lowered to engage the sealing edge of the workpiece on to support rollers 19 and lifted therefrom by a first reciprocation motor HUDC, a grinding wheel 27 rotatable by a second rotary motor GWM and movable into a contacting position against the sealing edge, a second reciprocation motor SAC which actuates biasing means in a first mode of operation and which moves this grinding wheel away from such position against the action of the biasing means in a second mode of operation, the grinding wheel being mounted on one end of a swingable support arm 25, and control means influenced by the swinging motion controlling the first or second rotary motor to provide uniform bevelling along the entire content of the sealing edge. The lower part of the apparatus consists of a tub 16, the bottom 16a of which has a plurality of brackets supporting horizontal rollers 11. The axes of the rollers are perpendicular to a central vertical axis C and the inner ends of the rollers are equally spaced from the axis and, in operation, the rollers support the panel P. Slurry is supplied to this apparatus during use and drains from the tub through an opening 16c. The upper part of the apparatus has an arm 39 formed by a plurality of welded plates 41...48. The first rotary motor HM is mounted on the arm 39 and is connected by a rod 106 to a coupling 110 in turn connected for relative axial movement to the shaft 61, the lower end of which carries vacuum chuck VC for holding the panel P. The shaft 61 is rotatable and axially slidable in a housing 56 secured to the arm and is also rotatable in but axially fixed to a housing 85 of a rotary union RU for the supply of vacuum to the chuck VC. A flange 85a of the housing 85 is connected to the rod PR2 of the first reciprocative motor HUDC whereby the shaft 61, and hence the chuck holding the panel, can be lowered to engage the panel P with the rollers and the shaft and panel rotated by the motor HM. The bevel is ground on the sealing edge of the panel by the grinding wheel 27 which has a torric configuration and is driven by the second rotary motor GWM comprising a pressurized fluid driven motor. The motor is adjustably mounted on the end of the support arm 25 secured to a vertical shaft 28 rotatably mounted in a bearing 30 carried by a boss 29 on the bottom 16a of the tub 16. The lower end of the shaft is secured to a bevel gear 31, pulley 33 and a crank arm 34. The crank arm 34 contacts a pin 35 on a crank arm 36 keyed to a shaft 37 which is rotatable in a bearing 62. A second crank arm 65 is also keyed to shaft 37 and is connected by a rod 66 to one end of a double armed lever 67 pivotally supported by a shaft 68, the other end of the lever being connected to the rod PR1 of the second reciprocative motor SAC. An arm 73 clamped to rod 66 is movable between adjustable abutments 76, 77 to determine the amount of movement of the rod by the motor SAC. An adjustable weight 90 is connected by a cable 87 to pulley 33 and acts on the shaft 28 and support arms 25 to urge the grinding wheel towards the panel. The bevel gear 31 engages a pinion on a shaft 95 carrying a cam 96 which acts upon a follower 103 to move a rod 108 of a transducer TD controlling the speed of the motor HM rotating the panel. The apparatus is operated by a control circuit having a number of contacts operated by a timer. With a panel held by the chuck, the timer causes operation of the motor HUDC to lower the shaft 61 and chuck until the sealing edge of the panel is supported by the rollers 19. The timer then operates motor HM to cause rotation of the shaft and panel and operates motor GWM to rotate the grinding wheel. Operation of motor SAC shifts rod 66 and crank arm 36 so that the weight 90 acts on shaft 28 and support arm 25 to urge the grinding wheel 27 into contact with the sealing edge to effect bevelling thereof. As the arm 25 moves about its pivot to follow the edge of the panel, the bevel gears 31 rotate cam 96 and operate the transducer which varies the speed of rotation of motor HM so that even grinding of the bevel is effected. Alternatively, the transducer could control the rotation of the grinding wheel motor GWM.