Method for forming a groove in a glass tube
AssigneeGTE Products Corporation
InventorJonathan M. Gregory
Life of this patent
Estimating the term…
Abstract
A method for forming a groove in a glass tube without contacting the glass tube in the groove region. The method includes the steps of rotating the glass tube about its longitudinal axis, heating a localized area of the glass tube where a groove is to be formed sufficiently to soften the glass tube in the localized area, stretching the glass tube along its longitudinal axis by a first distance sufficient to cause a reduction in the diameter of the glass tube in the localized area, and compressing the glass tube along its longitudinal axis by a second distance sufficient to produce a groove in the localized area. The glass tube is rotated during the steps of heating, stretching and compressing the glass tube. Heating is preferably performed by directing the flames from one or more torches at the groove area.
Claims22
A method for forming a groove in a glass tube, comprising the steps of:
- rotating the glass tube about its longitudinal axis;
- heating a localized area of the glass tube where a groove is to be formed sufficiently to soften the glass tube in the localized area;
- stretching the glass tube along its longitudinal axis by a first distance sufficient to cause a reduction in the diameter of the glass tube in the localized area;
- and
- compressing the glass tube along its longitudinal axis by a second distance sufficient to produce a groove in the localized area, said steps of heating, stretching and compressing the glass tube being performed during rotation of the glass tube.
A method for forming a groove in a glass tube, comprising the steps of:
- clamping end portions of the glass tube;
- rotating the glass tube about its longitudinal axis;
- heating a localized circumferential area of the glass tube where a groove is to be formed sufficiently to soften the glass tube in the localized area;
- terminating heating of the glass tube;
- before substantial cooling of the glass tube, pulling said end portions of the glass tube along its longitudinal axis by a first distance sufficient to cause a reduction in the diameter of the glass tube in the localized area;
- and
- before the glass tube hardens, pushing end portions of the glass tube along its longitudinal axis by a second distance sufficient to produce a groove in the localized area, said steps of heating, pulling and pushing the glass tube being performed during rotation of the glass tube.
Dependencies are inferred from the claim text.