GB338778A - Improvements in or relating to apparatus for severing the edges of glass sheets - Google Patents

Abstract

338,778. White, A. E., (Pittsburgh Plate Glass Co.). Dec. 24, 1929. Cutting.-Relates to the apparatus described in Specification 338,045 for removing the edges of a continuously-formed ribbon of glass. The invention consists in providing means for removing the edge-severing strips in advance of the application of heat to the transverse strips, and for supporting them so that they adjust themselves to the position of the glass ribbon. The invention, as described in the prior Specification, is used in conjunction with a device for cutting off sections from the continuous ribbon of glass by electrically heating the glass along a transverse line and then chilling it to cause it to crack. This device comprises a pair of strips of high resistance metal supported on each side of the glass ribbon 2 by bars 4, 5 carried by levers 17 pivoted to frames 6. A solenoid 14, when energized, forces the strips into contact with the glass. The frames 6 are suspended by a cable 7 to which counterbalance weights 11 are attached, and the frames can move upwards with the glass ribbon when the strips are in contact with it. After the glass has been heated sufficiently, a tool is applied to cause it to crack and the section of glass so detached is removed to a rack. The edge removing device which forms the present invention includes two vertical bars 21 each of which supports a resistance strip 23. The bars are carried by guide bars 27 which can slide vertically through brackets 29, 30 forming parts of a frame 31, 32. Each bar 21 is supported by a cable 36 and is balanced by a counterweight 35. The frame member 31 can be adjusted in relation to the member 32 by a brace 41, and the whole frame is pivoted on a standard 45. The position of the standard is adjustable on the platform 3, and this adjustment, in conjunction with stop screws 48, 50, enables the resistance strips to be adjusted in relation to the surface of the glass ribbon 2. In use, the resistance strips are supplied with current before the solenoids 14 are energized to clamp the bars 4, 5 against the glass, so that the strips 23 heat lines along the edges of the glass before it is heated along the transverse lines. After the bars 4, 5 are clamped to the glass, they move upwards with it until they engage the bars 21 thus causing the vertical heaters to move with the glass during the remainder of the heating- period. After the section of glass is cracked-off and removed, it is chilled along the vertical heated lines by the application of a wetted tool and the edges are thus cracked off. The. heaters return by gravity to the starting-position after the section of glass has been removed. The heating-strips need not be in contact with the glass but may be supported a. little distance from it so that it is heated by radiation. This may be done by setting each strip in a groove on its supporting-bar, and by providing the bar with a distance piece which prevents it from touching the glass