US2705390A

US2705390A - Method of and apparatus for cutting a moving ribbon of glass

Info

Publication number: US2705390A
Authority: US
Inventors: Peter M Denlow
Original assignee: Pilkington Brothers Ltd
Current assignee: Pilkington Group Ltd
Priority date: 1952-11-14
Filing date: 1953-10-09
Publication date: 1955-04-05
Anticipated expiration: 1972-04-05

Description

April 5, 1955 P. M. DENLOW METHOD OF AN D APPARATUS FOR CUTTING A MOVING RIBBON OF GLASS 4 Sheets-Sheet 1 Filed Oct. 9, 195-3 H11 HIIHIIIIIIIIIIIIIIH Inventor {6: iltorney;

April 5, 1955 P. M. DEN LOW METHOD OF AND APPA RATUS FOR CUTTING A MOVING RIBBON 0F GLASS Filed Oct. 9, 1953 4 Sheets-Sheet 2 Inventor April 5, 1955 p M, ow 2,705,390

METHQD OF AND APPARATUS FOR CUTTING A MOVING RIBBON 0F GLASS Filed ot. 9. 1953 4 She ets-Sheet s Inventor Attorney;

Aprll 5, 1955 P. M. DENLOW 2,705,390 METHOD OF AND APPARATUS FOR CUTTING A MOVING RIBBON OF GLASS Filed Oct. 9, 1955 4 Sheets-Sheet 4 ln venlor By v MWAUQM J United States Patent METHOD OF AND APPARATUS FOR CUTTING A MOVING RIBBON OF GLASS Peter M. Denlow, Eccleston, near St. Helens, England, assignor to Pilkington Brothers Limited, Liverpool, England, a British company Application October 9, 1953, Serial No. 385,191

6 Claims. (Cl. 4948) This invention relates to a method of and apparatus for producing glass sheets of predetermined size from a moving ribbon of glass.

As is well understood in the art, in one method of the manufacture of sheet glass a continuous ribbon of glass issues from an annealing chamber of a drawing kiln, and during the upward movement of the ribbon a horizontally moving scoring device makes an excursion across the width of the ribbon (e. g. as is described in United Kingdom Patent No. 456,822) to form therein during movement in one direction a transverse score line at a predetermined interval from the leading edge according to the desired lengths of sheets to be divided from the ribbon.

The intervals of operation of the scoring device are determined by a switch operated by the leading edge of the ribbon, and the demarked leading end portion of the ribbon is gripped by suckers (e. g. as described in United States Patent No. 2,628,453) and snapped off along the score line. Thereafter each snapped-01f portion is laid flat on a table and longitudinal score lines are manually formed therein along which the glass is snapped to trim off unwanted marginal portions and, if desired, to divide the portion into sections (in sheet form) of desired width.

A main object of the present invention is to provide a method of and an apparatus for producing glass sections in sheet form of predetermined dimensions from a moving ribbon of glass whereby the transverse and longitudinal score lines are formed in the moving ribbon of glass, and so to arrange the score lines that irregular breaking of the glass does not occur.

According to the present invention a method of producing glass sections in sheet form of predetermined dimensions from a moving ribbon of glass is characterised by defining the width of the sections to be produced by forming longitudinal score lines in spaced relation on one face of the moving ribbon, and interrupting each longitudinal score line for a short distance at such a distance from the leading edge of the ribbon that a transverse score line, formed on the other face of the ribbon to determine the length of a sheet, does not cross the longitudinal score lines and does not prematurely start division of the ribbon along the longitudinal score lines in order that a sheet, snapped from the ribbon along a transverse score line, may be snapped subsequently along the longitudinal scorelines in the sheet to obtain the glass sections of predetermined size.

Further according to the present invention, there is provided in apparatus for vertically drawing fiat glass in ribbon form including means for scoring a line of breakage across the ribbon emerging from the annealing chamber of a drawing kiln at a predetermined distance from the leading edge of the ribbon; retractable cutters for forming longitudinal score lines in spaced relation on the moving ribbon operatively associated with interrupting mechanism, said interrupting mechanism comprising a settable switch actuated by the leading edge of the ribbon, said settable switch controlling an electrical circuit comprising actuating means associated with a spring controlled valve to move the latter to the open position, a piston working in a cylinder supplied with motive fluid through said valve, means operatively associated with the piston and said actuating means for dissociating the actuating means for said valve from said valve to permit said valve to return to closed position, said piston actuating the retractable scoring means to move them out of operative position, and means for returning the actuating means "ice into association with the valve, and the retractable scoring means to operative position when the fluid is cut off from the cylinder.

The invention comprehends a novel method of operation in which the score lines are so arranged as not to cross each other, as viewed through the glass, and by this arrangement premature breaking at the longitudinal score lines when the glass is snapped at the transverse score lines is avoided.

In order that the invention may be clearly understood one preferred embodiment thereof as applied to the annealing chamber of a vertical drawing kiln will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

Fig. 1 is a diagrammatic side elevation of apparatus according to the invention,

Fig. 2 illustrates, to a relatively small scale, the manner in which transverse and longitudinal scores are formed in a moving glass ribbon.

Fig. 3 illustrates, to the same scale as used in Fig. 2, a leading end portion of the ribbon. after it has been snapped from the ribbon,

Fig. 4 illustrates to the same scale at Fig. 3 the portions shown in Fig. 3 after snapping thereof has been effected along the longitudinal scores formed therein to complete the production of glass sections of predetermined dimen- SlOIlS.

Fig. 5 is a broken plan of part of the device which makes the longitudinal score lines,

Fig. 6 is a fragmentary sectional elevation taken on line VI-VI of Fig. 5, and

Fig. 7 is a pictorial illustration showing diagrammatically one of the longitudinal scoring devices and actuating mechanism therefor, the transverse scoring device being omitted for the sake of clarity.

In the drawings like references indicate the same or similar parts.

Referring to the drawings, a continuous ribbon 1 of glass is drawn upwards through an annealing chamber indicated at 2 of a vertical drawing kiln (not shown) by a vertical series of pairs of rollers (mounted within the annealing chamber) of which one pair only is indicated at 3, Fig. 1. These rollers 3 are driven in known manner by gears, not shown, from a shaft 4 rotated by a pulley 5 and multiple belt 6 from the output shaft of an infinitely variable gear coupled to an electric motor (not shown).

The ribbon 1 is advanced by the rollers in the annealing chamber at a constant speed and a transverse score line T, F1g. 2, is formed on one face thereof at a predetermined interval from the leading edge of the ribbon according to the required length of the sheet sections to be separated in succession from the ribbon, by a transverse scoring device 7 mounted on a carriage 8, reciprocable across the ribbon 1 by wire cable 9.

Movement of the carriage 8 may be controlled conveniently in the manner described in United Kingdom spec fication No. 456,822. Movement of the carriage 8 is initiated by the closing of a mercury switch 10 adjustab1y mounted on a post 11 for pivotal movement by the leading edge of the advancing ribbon 1. At the end of a to-and-fro excursion of the carriage 8, the carriage is halted until a subsequent actuation by closing of the mercury switch 10.

The scoring device 7 acts against the rear face of the Ilbl'JOIl 1, which is supported against the thrust of the device by a roller 12. The scoring device 7 engages the ribbon only while being moved in one direction across the ribbon and the transverse score line T, Fig. 2, formed by it does not extend to the longitudinal edges of the ribbon but stops just short thereof. Accordingly the ribbon is not weakened across its entire width and this provision ensures that snapping of the glass along a transverse score line T does not occur prior to the leading end portion of the ribbon reaching a position at which it can be snapped oif under proper control. This may, in known manner, be effected by atilting sucker device 13, Fig. 1, which may be of the form described in United States Patent No. 2,628,453 which is moved into gripping engagement with the front of the glass and then forwardly tilts the leading end portion of the ribbon so that it snaps along the line T, the snapped-01f portion as illustrated in Fig. 3 being then lowered by the sucker device on to a portable frame or table. The thrust of the suckers 13 against the ribbon is counteracted by means of rollers 14 mounted on arms 15, whose position may be adjusted by the levers 16.

Below the transverse scoring device 7, Fig. 1, are provided three retractable scoring devices 17, the number of such devices depending on the number of sections in sheet form into which a leading portion of the ribbon 1 is to be divided. In Fig. 2 is illustrated a part of a leading portion of a ribbon intended to be divided into two sections S1, S2, Fig. 4, and the unwanted marginal portion E of the ribbon removed therefrom. Accordingly three retractable scoring devices 17 for producing the requisite longitudinal score lines are provided, only one of which is illustrated in Figs. to 7, and these form three longitudinal score lines L1, L2, and L3, Fig. 2, in the ribbon, before the leading portion is demarked by the transverse scoring device 7. As can be seen from Fig. l, the scoring devices 17 are located below the device 7 and act against the front face of the ribbon. To prevent the ribbon snapping along the lines L1, L2 and L3 before such action can be performed under proper control, and also to avoid irregular breaking, the operation of the retractable scoring devices 17 is interrupted at predetermined intervals so that the score lines L1, L2, L3 are each interrupted for a short distance D, see Fig. 2, at such a distance from the leading edge of the ribbon 1 that a transverse score line T, as viewed through the glass ribbon, does not cross the longitudinal score lines L1, L2, L3.

Referring now in particular to Figs. 5 and 7 of. the

drawings of which Fig. 7 illustrates diagrammatically one form of apparatus for interrupting the operation of the retractable scoring devices 17, each scoring device 17 is carried by an arm 18, supported by a pivot pin 19, Figs. 6 and 7 in a frame 20 on a bracket 21 secured to a cross bar 22 fixed by bolts 23, Fig. 5, to brackets 24 mounted on the machine frame 25. The bracket 21 is slidable along the cross bar 22 to permit the position of the scoring device 17 to be adjusted relative to the longitudinal edges of the ribbon 1, and the frame 20 is pivoted at 26 to the bracket 21 to permit the frame 20, arm 18 and device 17 to be swung anti-clockwise as viewed in Fig. 6, about the pivot 26 to inactive position. The scoring device 17 is maintained in operative engagement with the ribbon 1 by a spring 27, Fig. 6, which 4,

acts on the arm 18 and is tensioned by an adjusting screw 28. The ribbon 1 is supported against the thrust of each scoring device 17 by rollers 29, Fig. 1.

Each of the scoring devices 17 is supported by the cross bar 22, as just described, and a bail 30 common to the devices 17 is provided to retract simultaneously the devices from operative engagement with the ribbon 1, the bail 30 being movable to engage the lower ends of the arms 18 and swing them anti-clockwise, as viewed in Fig. 6. The bail 30 is supported at its ends by rocking arms 31 pivoted on bolts 32, Fig. 5, carried in the brackets 24, and connecting

rods

33, 34, connect the rocking arms 31 with bell-

cranks

35, 36 secured to a fixed cross-shaft 37 journaled in bearings 38 supported by a bearer 39 secured to the machine frame 25. The bell-crank carries a pin 40 to which is connected a spring 41.

Operation of the bail 30 is initiated by a second mercury switch 42, Figs. 1 and 7, pivotally supported by the post 11 for engagement by the leading edge of the ribbon 1 at a predetermined distance in advance of which the switch 10 is engaged by the leading edge of the ribbon. The switch 42 is so spaced from switch 10 that it initiates operation of the bail 30 to retract the scoring devices 17 from the ribbon at the predetermined position on the ribbon in advance of that at which the ribbon is to be engaged by the transverse scoring device 7, and mechanism about to be described permits the bail to be restored to its inactive position, clear of the arms 18, after a predetermined interval of time, this interval being so chosen that by retracting the scoring devices 17 from the ribbon and then restoring them to operative engagement therewith the longitudinal score lines L1, L2, L3 formed in the ribbon are interrupted at a predetermined distance from the leading edge of the ribbon to provide for a distance D, Fig. 2, the area of the ribbon which is not scored longitudinally and across substantially the centre of which, considered in the direction of movement of the ribbon, the transverse score line T is formed so that it does not cross the longitudinal score lines L1, L2, L3 as viewed through the ribbon.

The

switches

10 and 42 are adjustable lengthwise of the post 11, a wing-nut 43, Fig. l, permitting adjustment of the switches roughly to determine the position at which switch 10 will be engaged by the leading edge of the ribbon 1 and adjusting screws 44, 45 permitting respectively fine adjustment of the height of switch 10 and adjustment of switch 42 relative to switch 10.

Referring to Fig. 7, the switch 42 is included in an electric circuit supplied with current through a manually operated switch 46. When the mercury switch 42 is actuated by the leading edge of the ribbon 1 it causes a contactor 47 to be closed so that current passes to and energises the coil of a solenoid 48. The solenoid 48 is provided with an armature 49 having a forked end carrying a pivot pin 50 from which depends a latch 51 having formed therein a latching notch 52 which normally engages one end of a lever 53 pivoted at 54, the other end of the lever engaging a spring-controlled plunger 55 of an air valve 56.

The inlet side of the air valve 56 is connected by piping 57 with a source, not shown, of compressed air and the outlet side of the valve is connected by piping 58 through a device 59 of known construction which permits air to pass freely to a cylinder 60 but obstructs air passing in the opposite direction, the degree of obstruction being controlled by an axially displaceable regulator 61. In the cylinder 60 works a piston 62 from which depends a piston rod 63 having at its lower end a fork 64 by which it is connected to the pin 40 carried by the bell-crank 35. The valve 56 is normally in the closed position.

The piping 57 on the inlet side of the air valve 56 includes a shut-off valve 65 by which air from a compressor, not shown, can be admitted to or excluded from the piping, a pressure reducing valve 66, and an air-line oiling point 67.

In operation, the switch 46 is closed, as shown in Fig. 7, and on actuation of the mercury switch 42 by the leading edge of the ribbon 1, the contactor 47 places the solenoid 48 in circuit and its armature 49 is actuated so that the latch 51 is drawn upwards, thus rocking the lever 53 to release the air valve 56 and permit the passage of air under pressure into the cylinder 60. The air entering the cylinder causes the piston 62 to be raised thus rocking the bell-

cranks

35, 36 clockwise, as viewed in Fig. 7 so that the bail 30 is moved towards the front of the ribbon 1, engages the lower ends of arms 18, and swings the retractable scoring devices 17 out of engagement with the ribbon.

The switch 42 remains operated for a period longer than that during which operation of the scoring devices 17 is to be interrupted and the interval during which the devices 17 remain ineffective is determined by an adjustable abutment comprising a set-screw 68 in a block 69 slidable lengthwise of the piston rod 63. A biased trip member 70 rests on the set screw 68 and as the piston rises the member 70 is rocked about its pivot 71 until a pin 72 on the trip member engages the latch 51 and rocks it clockwise, Fig. 7, about its pivot 50 until it is disengaged from the lever 53, as indicated in chain-lines, Fig. 7. The spring-controlled plunger 55 is then released, thus cutting off the supply of air under pressure to the cylinder 60 whereupon

weights

73 and 74 carried respectively by the piston rod 63 and the bell-crank 36 cause the piston to descend at a rate regulated by the regulator 61 and the air in the cylinder to be exhausted by the valve 56, through an exhaust pipe 75. As the piston descends, the trip member 70 automatically returns to pristine position, the bell cranks 35, 36 and the bail 30 are also gradually restored to their starting positions thus permitting the scoring devices 17 to reengage the ribbon 1. The mercury switch 42 returns to its normal inoperative position when, under proper control the leading end portion of the ribbon is snapped off in known manner along a score line T by means of the tilting sucker device 14, and the electric circuit is then broken through the contactor 47 so that the solenoid 48 is de-energised and the latch 51 reassumes a vertical position, engaging the control lever 53.

The distance D, Fig. 2, between the adjacent ends of successive longitudinal score lines may be about one inch.

It should, however, be so chosen that on each side of the transverse score line T is a distance not less than about one-quarter of an inch wide which is not weakened by longitudinal score lines. Adjustment of the distance D between the adjacent ends of successive longitudinal score lines may, as desired, be obtained by adjusting the position of the abutment 68 on the piston rod 63.

When the leading end portion of the ribbon reaches a predetermined position it is, in known manner, as mentioned above, and under proper control, snapped off the ribbon along the transverse score line T. Theportion of ribbon as illustrated in Fig. 3, so removed is disposed on a portable frame or a table and then, again under proper control, the marginal portions E, Fig. 4, are snapped off along the lines L1, L3 and the remaining portion is then snapped along line L2 to produce two glass sections S1, S2 in sheet form of predetermined dimensions.

I claim:

1. A method of producing glass sections in sheet form of predetermined dimensions from a moving ribbon of glass characterised by defining the width of the sections to be produced by forming longitudinal score lines in spaced relation on one face of the moving ribbon, forming transverse score lines on the other face of the ribbon to determine the length of the sections, interrupting each longitudinal score line for a short distance at such a distance from the leading edge of the ribbon that a transverse score line does not cross the longitudinal score lines and does not prematurely start division of the ribbon along the longitudinal score lines when the ribbon is snapped along a transverse score line, and snapping the ribbon along a transverse score line and subsequently along the longitudinal score lines to obtain the glass sections of predetermined size.

2. In apparatus for vertically drawing flat glass in ribbon form including means for scoring a line of breakage across the ribbon emerging from the annealing chamber of a drawing kiln at a predetermined distance from the leading edge of the ribbon; retractable cutters for forming longitudinal score lines in spaced relation on the moving ribbon, operatively associated with interrupting mechanism, said interrupting mechanism comprising a settable switch actuated by the leading edge of the ribbon, a spring controlled valve, actuating means for said valve and electrical means controlled by the said settable switch for activating the said actuating means to move the valve to the open position, a piston working in a cylinder supplied with motive fluid through said valve, means operatively associated with the piston and said actuating means for dissociating the actuating means for said valve from said valve to permit said valve to return to closed position, means operatively connecting said piston to the retractable cutters to move them out of operative position upon admission of fluid to the cylinder, and means for returning the retractable cutters to operative position and the piston and the dissociating means respectively to the inoperative position when the fluid is cutoff from the cylinder.

3. Apparatus according to claim 2 including means adjustably associating the dissociating means with the piston whereby the means for dissociating the actuating means for said valve is adjustable with respect to the piston so that the period of dissociation may be regulated.

4. In apparatus for vertically drawing flat glass in ribbon form including means for scoring a line of breakage across the ribbon emerging from the annealing chamber of a drawing kiln at a predetermined distance from the leading edge of the ribbon: retractable cutters for forming longitudinal score lines in spaced relation on the moving ribbon, an interrupting mechanism operatively associated with said retractable cutters, said interrupting mechanism comprising a settable switch actuated by the leading edge of the ribbon, said settable switch controlling a circuit comprising a solenoid to which a vertically disposed latch is hinged, whereby the latch is raised when the circuit is energised, a piston working in a cylinder, a spring controlled valve controlling supply of motive fluid to the cylinder, said valve being normally held in the closed position, a control lever connected with the valve and engaged by the latch whereby the valve is moved to open position when the latch is raised, a piston rod connected to the piston, means articulated to said rod for moving the retractable scoring means out of the normal (operative) position when the switch is actuated, a biased trip supported for actuation by said piston rod and disposed in proximity to the latch so that in one direction of movement of the rod the trip disengages the latch from the control lever and frees the valve to return to closed position for the fluid, said trip automatically regaining pristine position in the other direction of movement of the piston rod; the arrangement being such that motive fluid is only passed to the piston cylinder when the latch rocks the control lever to move the valve to the on position, achieved by the operation of the settable switch, said latch being reset when the switch resets and de-energises the circuit.

5. Apparatus according to claim 4 including an abutment supported by the piston rod for actuating the trip and means adjustably securing the abutment with respect to the piston rod, the period of admission of motive fluid being regulated by the setting of the abutment on the piston rod.

6. Apparatus according to claim 4 wherein the means for moving the retractable scoring means comprises a biased bell crank operatively connected to the piston rod, a bail disposed transversely of the ribbon to engage the retractable scoring device and links connecting the bell crank to the bail for retracting the scoring device when motive fluid is admitted to the piston cylinder.

Williamson Apr. 19, 1932 Hinkle Oct. 21, 1.941