Vacuum holder system and method for use in bending glass

A system for use in bending glass comprising:

• a vacuum holder having a downwardly facing surface including spaced openings therein;
• a roller conveyor for conveying a heated sheet of glass below the vacuum holder in a vertically spaced relationship thereto;
• first means for providing relative vertical movement between the holder surface and a heated sheet of glass below the holder surface on the conveyor so as to position the holder surface in proximity with the heated sheet of glass;
• blower means for drawing a vacuum and supplying positive gage pressure air;
• and damper means for communicating the blower means with the holder surface openings to initially draw a vacuum within the holder surface openings to engage and support a heated glass sheet in proximity therewith against the downwardly facing holder surface and the damper means subsequently reducing the extent of vacuum drawn to prevent deformation of the heated sheet of glass at the openings in the holder surface, the first means being operable to position the holder surface with the heated sheet of glass thereon above the roller conveyor in a spaced relationship such that a mold can be moved under the holder above the conveyor, and the damper means finally supplying positive gage pressure air from the blower means to the holder surface openings to force the glass sheet downwardly away from the holder surface so that bending can take place on the mold.

A system for use in bending glass comprising:

• a vacuum holder having a downwardly facing surface including spaced openings therein;
• a roller conveyor for conveying a heated sheet of glass below the vacuum holder in a vertically spaced relationship thereto;
• first means for providing relative vertical movement between the holder surface and a heated sheet of glass below the holder surface on the conveyor so as to position the holder surface in proximity with the heated sheet of glass;
• a first vacuum blower;
• a second positive pressure air blower;
• a damper including a housing for communicating the first and second blowers with the holder surface openings;
• the damper having vanes projecting from a common axis about which the vanes are mounted for rotation with each other within the housing;
• and an actuator that rotates the damper vanes within the housing to initially communicate the vacuum blower with the holder surface openings to engage and support a heated glass sheet in proximity therewith against the downwardly facing holder surface and the actuator subsequently rotating the damper vanes to reduce the extent of vacuum drawn by the vacuum blower to prevent deformation of the heated sheet of glass at the openings in the holder surface, the first means being operable to position the holder surface with the heated sheet of glass thereon above the roller conveyor in a spaced relationship such that a mold can be moved under the holder above the conveyor, and the actuator subsequently rotating the damper vanes to finally communicate the positive pressure air blower with the holder surface openings to supply positive gage pressure air thereto so as to force the glass sheet downwardly away from the holder surface so that bending can take place on the mold.

A system for use in bending glass comprising:

• a vacuum holder having a downwardly facing surface including spaced openings therein;
• a conveyor for conveying a heated sheet of glass below the vacuum holder in a vertically spaced relationship thereto;
• a first vacuum blower;
• a second positive pressure air blower;
• a damper including a housing for communicating the first and second blowers with the holder surface openings;
• the damper having three vanes projecting from a common axis about which the vanes are mounted for rotation with each other within the housing;
• said damper housing having an opening to the atmosphere;
• and an actuator including a digital positioner that rotates the damper vanes within the housing to (1) initially communicate the vacuum blower with the holder surface openings to engage and support a heated glass sheet from the conveyor against the downwardly facing holder surface, (2) subsequently reduce the vacuum drawn within the holder surface openings by the vacuum blower to prevent deformation of the heated glass sheet at the openings, (3) thereafter communicate the positive pressure air blower with the holder surface openings to supply positive gage pressure air thereto so as to force the glass sheet downwardly away from the holder surface, and (4) finally isolate the first and second blowers as well as the damper housing opening from the holder surface openings while allowing pressurized air from the second blower to be exhausted to the atmosphere.

A method for supporting and quick releasing heated sheets of glass being conveyed for processing, the method comprising:

• conveying a heated sheet of glass on a roller conveyor to below a downwardly facing surface of a vacuum holder;
• providing relative vertical movement between the heated sheet of glass and the holder to position the sheet of glass in proximity to the holder surface;
• initially drawing a sufficient vacuum within spaced openings in the downwardly facing surface of the vacuum holder so as to support the heated sheet of glass in engagement therewith;
• then reducing the degree of vacuum drawn within the holder surface openings to prevent deformation of the heated glass sheet at the openings;
• positioning the holder surface with the heated sheet of glass thereon in a spaced relationship above the roller conveyor so a bending mold can move between the conveyor and the holder surface;
• and subsequently supplying positive gage pressure air to the holder surface openings to force the sheet of glass downwardly away from the holder surface.

A method for supporting and quick releasing a heated sheet of glass being conveyed for processing, the method comprising:

• conveying a heated sheet of glass on a roller conveyor to below a downwardly facing surface of a vacuum holder;
• providing relative vertical movement between the heated sheet of glass and the holder to position the sheet of glass in proximity to the holder surface;
• communicating a vacuum blower with spaced openings in the downwardly facing surface of the vacuum holder so as to support the heated sheet of glass in engagement therewith;
• then reducing the degree of vacuum drawn within the holder surface openings to prevent deformation of the heated glass sheet at the openings;
• positioning the holder surface with the heated sheet of glass thereon in a spaced relationship above the roller conveyor so a bending mold can move between the conveyor and the holder surface;
• and subsequently communicating a positive pressure air blower with the holder surface openings to force the sheet of glass downwardly away from the holder surface.

A system for use in bending glass comprising:

• a heating chamber;
• a conveyor for conveying glass to be heated through the heating chamber;
• a holder located above the conveyor within the heating chamber;
• the holder including a plenum and a downwardly facing surface having restricted openings communicating the plenum and the heating chamber;
• a gas jet pump located within the heating chamber and having a passage that communicates the holder plenum and the heating chamber;
• and a pressurized gas source located externally of the heating chamber and communicated with the passage of the jet pump so as to produce a primary gas flow therethrough away from the holder plenum toward the heating chamber in order to thereby induce a secondary gas flow from the plenum to the heating chamber such that a vacuum is drawn at the holder surface openings to receive a heated sheet of glass from the conveyor and support the glass sheet against the holder surface.

A system for use in bending glass comprising:

• a heating chamber;
• a conveyor for conveying glass to be heated through the heating chamber;
• a holder located above the conveyor within the heating chamber;
• the holder including a plenum and a downwardly facing surface having restricted openings communicating the plenum and the heating chamber;
• a gas jet pump located within the heating chamber and having a passage that communicates the holder plenum and the heating chamber;
• the pump having jet openings into the passage;
• said jet openings being inclined axially along the passage in a direction away from the holder plenum toward the heating chamber;
• a pressurized gas source located externally of the heating chamber and communicated with the jet openings of the jet pump so as to produce a primary gas flow in the jet pump passage away from the holder plenum toward the heating chamber in order to thereby induce a secondary gas flow from the plenum to the heating chamber such that a vacuum is drawn at the holder surface openings to receive a heated sheet of glass from the conveyor and support the glass sheet against the surface;
• and a heater for heating the pressurized gas prior to introduction thereof into the gas jet pump.