Method and apparatus for removing a marginal zone external of an outline cut in a glass sheet

Abstract: The invention relates to a method and an apparatus for removing a marginal zone (10) external of an outline (7) cut in a glass sheet, in which method a glass sheet (6) is carried by means of a suction-padded (4) conveyor carriage (1) to a marginal zone removing station, wherein the marginal zone (10) to be re­ moved is subjected to the action of a heating flame by means of a flame burner. During or after the flame heating, the removal of marginal zone (10) is secured by means of mechanical removing members (8) fixed to conveyor carriage (1) and brought to collide with a possibly un­ removed edge zone (10) by moving suction pads (4) and removing members (8) relative to each other. Preferably vertically movable removing members (8) are fixed to suction-pad rods (5) for automatically setting them in a correct position in alignment with marginal zone (10) to be removed.

Description: The present invention relates to a method for removing a marginal zone of glass sheet from an inner zone thereof. Furthermore the invention relates to an apparatus for carrying out the method. The apparatus includes a conveyor carriage fitted with ascendable and descendable suction pads and a marginal zone removing station fitted with flame burners for applying a heating flame to the marginal zone to be removed. From US-A-4698088 a glass plate fabrication machine suitable to small lot production for a wide variety of articles such as window glass of automobiles, for example, side windows, front windows, rear windows and rear quarters are known. US-A-4698088 shows a method like the one defined in claim 1, but with the differences indicated hereinafter. A protrusion 65 is mounted at the end of a piston rod 64, and a marginal zone outside an outline cut is broken by descending the piston rod and protrusion so that the protrusion strikes the marginal zone, and by raising the inner zone of the glass sheet with a suction-pad. In contrast thereof in the present invention the inner zone of the glass sheet is raised, while the outer edge of the marginal zone is restrained against upward movement. As shown in figure 13 of the US-A-4698088 the protrusion 65 engages the marginal zone at a location spaced inwardly from the outer edge thereof, rather than contacting the outer edge. Additionally the prior art discloses separate brackets 57 and 67, respectively, for a suction-pad 56 and protrusion (removing means) 65. If the suction-pad 56 is horizontally moved relative to the transport frame 55, the protrusion 65 is not moved therewith. In contrast thereto the removing means 8 of the present invention are secured to suction-pad rods, whereby the removing means automatically follow the movements of the suction-pads, when they are horizontally moved relative to the conveyor carriage. This feature has a purpose that both the suction-pads and the removing means can be moved in unison with the correct location when the type of glass (size and shape) is changed. The currently available solutions include a flame-effected removal on the one hand and a mechanical removal on the other. In the flame-effected removal procedure, a marginal zone to be removed is first subjected to a heating flame and the corners are then cut open by sharp cutting flames. A drawback in flame-effected removal is a wide marginal zone required thereby, resulting in a large loss of glass. Another drawback is that automatization of a plurality of flame stations is complicated in mixed production. In mechanical removal, the opening of corners is effected by means of a cutting knife and it further requires the use of presses for forcing the marginal zone loose. First of all, a drawback is that two separate removing stations are required and, furthermore, this removing method is also difficult to automatize in mixed production. An object of the invention is to provide a method and an apparatus applicable to the removal of a marginal zone in a glass sheet, which make it possible to remove a very narrow marginal zone (5 - 10 mm) and whose operation can be automated in a simple fashion. This object is achieved by means of the invention on the basis of the method features set forth in the annexed claim 1 and the apparatus features set forth in claim 2. One embodiment of the invention will now be described in more detail with reference made to the accompanying drawings, in which fig. 1 illustrates a mechanical cut-off means included in an edge-removing apparatus of the invention and connected to the suction-pad rod of a conveyor carriage. The apparatus is shown at the first removing stage with a flame heating applied to a marginal zone 10 to be removed. Fig. 2 shows the apparatus of fig. 1 at the second removing stage with mechanical cut-off means 8 colliding against a possibly non-removed marginal zone 10 for removing it from a glass sheet 6. Fig. 3 shows an edge-removing station 2 in a schematic plan view. A method and apparatus of the invention can be applied e.g. in the connection of an assembly described in FI Patent application 885048, with publication no. 89039. A conveyor carriage 1 fitted with suction pads 4 is used to carry a glass sheet 6 from an edge-cutting station to a marginal-zone removing station and, after the removal, further to an edge-grinding station. In the edge-cutting station, a rectangular glass sheet 6 is provided with a cut outline 7, whereby a marginal zone 10 remaining outside said outline is to be removed in an edge-removing station 2. In the edge-removing station, said glass sheet 6 is lowered e.g. upon a grid-like base by descending a portion of carriage 1 having suction-pad rods 5 mounted thereon. This is followed by subjecting the four corners of glass sheet 6 to the action of heating flames by means of flame burners 3, the thermal stresses produced thereby removing and crushing said marginal zone 10 external of outline 7. However, along the long sides of glass sheet 6, the long and narrow marginal zones 10 do not always come loose. In this invention, the removal thereof is secured by means of mechanical removing members 8 which are mounted on rods 5 of suction pads 4 by means of horizontal brackets 14. Thus, the removing members 8 are spaced a certain horizontal distance from suction pads 4. As the size of a glass sheet changes, the location of suction pads 4 is adjusted by displacing suction-pad rods 5 in horizontal direction and, thus, said removing members 8 are also automatically carried to a correct location within the boundaries of a marginal zone 10 to be removed. A spring 11 urges said removing members 8 downwards. A rod 12 is movable through a linear bearing 13, whereby said removing member 8 can be urged upwards against the force of spring 11. The cut-off head of a removing member 8 is provided with a bottom surface 9 bevelled to rise from outside towards inside, whereby the removing member 8 does not require exactly precise positioning in lateral direction. When a glass sheet 6 is laid upon the base of an edge-removing station, said removing members 8 collide with the base and rise upwards against the force of spring 11 (fig. 1). This is followed by a heating shock effected by flame burners 3 for breading and removing the marginal zone 10. However, along the long sides there may remain unroved edge portions if the zone 10 to be removed is narrow. This is followed by lifting glass sheet 6 by means of suction pads 4. The tension of spring 11 prevent removing members 8 from rising along, the possibly unremoved edge portions 10 striking against said inclined bottom surfaces 9 of removing members 8 for detaching said marginal zone 10 along outline 7. The glass sheet is ready to be carried to an edge-grinding station. It is obvious that the invention is not limited to the above preferred embodiment but many modifications of the invention are conceivable within the scope of the annexed claims. For example, the relative movement of removing members 8 and suction pads 4 can be arranged in a variety of ways.

Claims: A method of removing a marginal zone (10) of a glass sheet (6) from an inner zone thereof, comprising the steps of: cutting an outline (7) in a glass sheet (6) to define an inner zone of the glass sheet located inside of the outline (7), and a marginal zone (10) of the glass sheet (6) located outside of the outline (7); positioning the glass sheet (6) on support surface means such that both said inner zone and said marginal zone (10) are supported from below by said support surface means; arranging a conveyor carriage (1) carrying suction pads (4) and mechanical removing means such that said suction pads (4) adhere to the inner zone of the glass sheet (6), and a bottom surface of said mechanical removing means (8) contacts an outer edge of the marginal zone (10), said bottom surface being beveled and extending downwardly so that a lowermost end thereof is situated outwardly relative to an innermost end thereof, said removing means and said suction pads (4) being capable of relative movement upwardly and downwardly; carrying the glass sheet (6) by means of the suction padded (4) conveyor carriage (1) to a marginal zone removal station; heating the marginal zone (10) by means of a flame burner (3) to at least partially remove the marginal zone (10) from the glass sheet (6); and raising said carriage (1) to move said suction pads (4) and inner zone upwardly relative to said bottom surface of said removing means (8) whereby said bottom surface restrains upward movement of the outer edge of the marginal zone (10), causing the marginal zone (10) to break along said outline (7) and being removed from said inner portion. An apparatus for removing a marginal zone (10) from a glass sheet (6), wherein the marginal zone (10) is located outside an outline cut in the glass sheet (6), comprising: a conveyor carriage (1) for carrying a glass sheet to the marginal zone removal station; a plurality of suction pad rods (5) mounted on said conveyor carriage (1) for movement therewith; a plurality of suction pads (4) mounted to said suction pad rods (5) for attachment to and carrying of the glass sheet (6); a plurality of mechanical removing means (8) mounted on respective rods of said suction pad rods (5), said removing means (8) and its respective suction pad rod (5) being capable of relative movement upwardly and downwardly; said removing means are provided with a contact surface (9) which is beveled in a manner that it rises when proceeding from the outer edge of removing means (8) towards the inner edge; means for heating the marginal zone (10) for at least partially removing the marginal zone (10) from the glass sheet (6), by heating means including flame burners (3); and means for moving said suction pad rods (5) and suction pads (4) upwardly relative to said mechanical removing means (8) whereby upward movement of the marginal zone (10) is restrained by said mechanical removing means (8) to cause the marginal zone (10) to be removed from the glass sheet (6); said suction pad rods (5) being horizontally movable relative to said conveyor carriage (1) so that said suction pads (4) and said mechanical removing means (8) can be horizontally adjusted relative to the glass sheet (6).

Inventors: IKOLA KIMMO JUHO, STENMAN KIMMO ENSIO, IKOLA, KIMMO JUHO, STENMAN, KIMMO ENSIO
Applicants: TAMGLASS ENG OY, TAMGLASS ENGINEERING OY
Application year: 1990
Main classification: C03B33
IPC codes: C03B33