Manufacture of flat glass having controlled width and nip width

A linear movement monitoring device used in combination with an attenuating apparatus of the type comprising means for applying translational and longitudinal forces to a glass ribbon moving along a glass ribbon movement path on a pool of supporting molten metal;

• means mounting the applying means for moving the applying means along a reciprocating path generally transverse to the glass ribbon movement path, comprising:
• means responsive to the movement of the moving means for generating a signal during movement of the moving means along the reciprocating path;
• and
• means responsive to said generating means for converting the signal from said signaling means to linear dimensions to determine distance and direction of movement of the moving means along the reciprocating path.

An angular movement monitoring device used in combination with an attenuating apparatus of the type comprising a base pivotally mounted for movement along a reciprocating arcuate path;

• means mounting the base for applying translational and longitudinal forces to a glass ribbon moving along a glass ribbon path on a pool of supporting molten metal;
• and means mounting the base for moving the base along the arcuate path, comprising:
• means responsive to the movement of the base along the arcuate path for generating a signal during movement of the base along the arcuate path;
• and
• means responsive to said generating means for converting the signal from said generating means to degrees to determine distance and direction of movement of the base along the reciprocating arcuate path.

An improved apparatus for attenuating a glass ribbon to be moved along a glass ribbon movement path on a pool of supporting molten metal wherein the attenuating apparatus is of the type comprising means for applying translational and longitudinal forces to the ribbon, the applying means including means for engaging the upper surface of the ribbon;

• a base pivotally mounted for movement along a reciprocating arcuate movement path relative to the glass ribbon movement path;
• means for moving the applying means along a first reciprocating path generally transverse to the glass ribbon movement path, and means for moving the base along the arcuate movement path, the improvement comprising:
• means for sensing the incremental displacement of the edge of the glass ribbon along a second reciprocating path generally parallel to the first reciprocating path;
• means for mounting said sensing means in spaced relation to the engaging means and over the surface of the supporting molten metal and upper surface of the glass ribbon;
• means responsive to said sensing means and acting on the moving means for moving the applying means in a first direction to increase nip width of the glass ribbon when the nip width as indicated by said sensing means is at least equal to or below minimum nip width of a predetermined range and for moving the applying means in a second direction opposite to the first direction to decrease the nip width when the nip width as indicated by said sensing means is at least equal to or greater than maximum nip width of the predetermined range;
• first means responsive to the movement of the means for moving the applying means for generating a signal during movement of the moving means along the first reciprocating path;
• first means responsive to said first generating means for converting the signal from said signaling means to linear dimensions to determine distance and direction of movement of the moving means along the reciprocating path;
• second means responsive to the movement of the base along the arcuate path for generating a signal during movement of the base along the arcuate path;
• and
• second means responsive to said second generating means for converting the signal from said generating means to degrees to determine distance and direction of movement of the base along the reciprocating arcuate path.

In a method of manufacturing flat glass comprising the steps of providing molten glass on a pool of supporting molten metal, flowing the molten glass downstream along a ribbon movement path on the pool of molten metal, applying attenuating forces upon the glass ribbon while cooling the glass ribbon to form a dimensionally stable ribbon wherein the attenuating forces are applied by attenuating means adjacent the edges of the glass ribbon at an angle to the normal of the glass movement path and the attenuating means are moveable along a reciprocating path generally transverse to the ribbon movement path;

• and removing the dimensionally stable glass ribbon from the supporting molten metal, the improvement comprising the steps of:
• measuring the distance between the edge of the ribbon and the position on the ribbon where the attenuating forces are applied to determine nip width;
• and
• moving the attenuating means in response to the measured distance (1) in a first direction along the reciprocating path to decrease the nip width when the nip width is greater than a predetermined amount and (2) in a second direction along the reciprocating path opposite to the first direction to increase the nip width when the nip width is less than a predetermined amount.

In a method of manufacturing a flat glass ribbon including the steps of containing a pool of supporting molten metal in a container having sidewalls spaced a known distance apart;

• providing molten glass on the pool of supporting molten metal;
• flowing the molten glass downstream along a ribbon movement path on the pool of supporting molten metal;
• applying attenuating forces upon the glass ribbon while cooling the glass ribbon to form a dimensionally stable glass ribbon wherein the attenuating forces are applied by rotary attenuating means adjacent the edges of the glass ribbon at an angle to the normal of the glass movement path, said attenuating means having an elongated axis which is pivoted about a vertical axis, said elongated axis being transverse to the glass movement path, and the attenuating means are reciprocably movable along an arcuate linear path;
• and removing the dimensionally stable ribbon from the pool of supporting molten metal, the improvement comprising the steps of:
• measuring the width of the ribbon at positions where the attenuating forces are applied;
• measuring the angle subtended by the elongated axis of the attenuating means and the ribbon path to determine the angle of attenuation;
• determining the incremental changes of the angle of attenuation required to provide a desired predetermined ribbon width;
• and
• moving the attenuating means along the arcuate linear path to change the angle of attenuation in an amount sufficient to provide the desired predetermined ribbon width at the positions on the ribbon where the attenuating forces are applied.