Patent GB-901794-A (GB)
Title: Glass cutting apparatus
IPC: C03B33/037
Filed: 1960-01-13
Abstract: 901,794. Cutting glass sheets. PITTSBURGH PLATE GLASS CO. Jan. 13, 1960 [Jan. 19, 1959], No. 1238/60. Class 56. Apparatus for cutting glass sheets comprises conveyer means to move in a given path a glass sheet having a leading edge, a glass scoring tool adapted to be moved transversely of the path of movement of the glass sheet to score the sheet, means adapted to sense the position of the leading edge of the moving glass sheet, motor means to move the sensing means in a path parallel to the path of movement of the glass sheet, the sensing means being adapted to initiate the transverse movement of the glass scoring tool and the movement of the sensing means being controllable by indicating means operatively connected to the sensing means so as to score a predetermined length of the glass sheet. The indicating means comprises first digit-signifying means to indicate by binary digital numbers actual positions of the sensing means in its path of movement, the first means being controllable by second digit-signifying means which indicates by a decimal digital number a predetermined position of the sensing means and therefore a length of glass sheet to be cut by the apparatus and converts the decimal digital number to the corresponding binary digital number for equation with the first digitsignifying means so that when a coincidence occurs between the numbers the operation of motor means for moving the sensing means is stopped. The glass sheet G is fed by rolls 33 of a conveyer 32 to a belt conveyer 40 and thence to rolls 29 of a conveyer 25, each roll of which can be rotated at slow speed or fast speed to separate a cut sheet from the main sheet. The belt conveyer 40 has belts 41 with a top horizontal run over idler pulleys 42, 43 and which are driven by pulleys 45 from a motor M, the belts 41 being supported by pairs of plates 77 and 61. Pulleys 42 are mounted on pairs of plates 58 pivoted on a shaft 59 and between each pair of plates 58 is mounted one of the plates 61. The plates 58 support a shaft 67 with cam followers 68 pressing against cam-plates 75 giving a normal intermediate position, a raised position in which the pulleys 42 snap the glass along a score line and a lowered position so that any glass, such as waste glass, can be conveyed off belts 41 to a Gullet hopper. Cam-plates 75 are keyed on shaft 73 which is connected by a link 72 to the piston-rod 71 of an hydraulic cylinder 69 operated from the intermediate position by a solenoid 1SV (not shown) to retract rod 71 to raise pulleys 42 for cracking off and by a solenoid 2SV (not shown) to extend rod 71 for removal of waste glass. Mounted above the glass sheet, on longitudinally extending plates 78, is a fixed bridge 95 and a carriage 85, for the cutter assembly, having double-flanged wheels 88 and V-shaped wheels 89 on end-plates 86, 87 to ride on support and guide-rails 79, 80 for movement with the glass sheet G. The bridge 95 comprises a tubular member 96 with brackets 97 supporting a shaft 99 and brackets 100 supporting a shaft 101. Racks 104 connected at one end to the plates 86, 87 of carriage 85 are slidably supported in saddle members 103 for engagement with gears 105 rotating on shaft 101, so as to synchronize the movements of the plates 86 and 87. Cam discs 106 keyed on shaft 99 are engaged in the home position of carriage 85 by cam followers 170 rotating on plates 86, 87 and the discs 106 are shaped to give a rapid initial acceleration of carriage 85. The shaft 99 is driven from an electric motor M1, continuously operated, through a single revolution clutch 112 having a driving sleeve 113 keyed by gears 114, 115 to the motor M1, the hub 116 of clutch 112 being keyed by pin 117 to shaft 99 and the clutch 112 being brought into operation by a trip cam 118 normally held out of operation by a bar 123 pivoted by a link to the end of the piston-rod 132 of a cylinder 133 operated by a solenoid 3SV (not shown). Carriage 85 is moved forwardly with the glass sheet G by engagement therewith of pairs of front or rear vacuum cups 195, 216, each pair mounted on carriage 85 by brackets 186 and a shaft 200 which has a cross-pin 204 resting on a pair of crank arms 189 fixed on shaft 188 mounted in bearings 187 on brackets 186. To lift the vacuum cups 195 or 216, the shaft 188 is rotated by crank arms 190 connected to the piston-rods 193 of air cylinders 194. To reduce the load on the vacuum cups 195 or 216 during movement of carriage 85, the plates 86, 87 are connected to the piston-rods of a pair of hydraulic cylinders 217 (Fig. 1) operated by a double solenoid four-way valve 218 (Fig. 3), energization of solenoid 13SV-A providing the forward force during cutting and the other solenoid 13SV-B (not shown) being energized to return the carriage 85 to its home position and hold it there. A bar 135 extending along one side of the apparatus has equally spaced knobs 136 on its top surface and a rack 137, with horizontallyextending teeth, mounted thereover. The bar 135 is mounted on spaced rollers 141 and guided by side rollers 142 supported by bars 138 and 143. At the forward end of bar 135 is mounted the sensing mechanism comprising a side arm 149 extending over the conveyer 25 and having a limit switch 1LS to be tripped by arms 153, 154, the arm 154 lying in the path of the moving glass sheet G. A roller 156 on arm 154 rolls on the glass till the trailing edge has passed, when arm 154 drops back and arm 153 opens limit switch 1LS. The bar 135 is moved according to the length of sheet required by engagement of rack 137 with a gear 292 driven from an hydraulic motor 290 through gear 291 and clutch MC-1 and is held in the required position by a pawl 160 mounted on the piston-rod 165 of air cylinder 166 so that retraction of rod 165 lowers extension 168 on pawl 160 between the knobs 136 on bar 135.  The cutting mechanism 230, which is similar to that .disclosed in Specification 900,983, is mounted on a support assembly 225 comprising a plate 226 having wheels 227 to ride in grooves 224 of a guide-plate 223 extending across carriage 85. The plate 226 has tape clamps 228 to engage a tape 229 passing round idler pulley 176 and pulley 179 driven by motor 181 to drive the assembly 225 to score the glass sheet G by wheel 231 and to return the assembly, the motor 181 being operated through limit-switches and solenoids to give fast speed, with slow start and finish, in either direction. A snapping assembly 250, to run the cut for the front and rear edge trims of a sheet, comprises spaced plates 251 supporting wheels 254 which ride on flanges secured to plates 245, the assembly being moved to and from operative position by an hydraulic cylinder 259 secured by its rod 258 to a plate 256 connected between plates 251. In the operative position, rollers 269 abut the sheet edge and the glass is opened by a head 279 moving up under the scored line between a pair of abutment heads 284, the head 279 being on a shaft 272 connected by links 275, 277 to the piston-rod 264 of hydraulic cylinder 265. The electric circuit disclosed includes a pair of binary drum switches 306, 307 for controlling the length of cut. The shafts 305 of the switches 306, 307 are keyed to shafts 300, 304, and the shaft 300 is connected through gears 299, 298 and 294 to mesh with the gear 292 driving the bar 137, the shaft 300 also having a timing gear 301 driving a timing belt 302 passing round a timing gear on shaft 304. The apparatus can be used in conjunction with an automatic inspection and computing device for determining a programme of cutting according to the position of defocts in the glass sheet. Specifications 901,795 and 901,796 also are referred to.