Method for controlling the rotary drive of a hot forming machine

Patent metadata

Field	Value
Publication number	US-11326675-B2
Application number	US-201916445630-A
Country	US
Kind code	B2
Filing date	Jun 19, 2019
Priority date	Jun 19, 2018
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

A method for controlling a rotary drive of a hot forming machine having a plurality of processing stations arranged in a circular manner and a rotary table arranged thereabove, in which glass tubes to be processed are held and moved from one processing station to the next by a stepwise rotary movement, is provided. The rotary table is driven by a step gear by which a movement of a drive shaft is translated into a cyclic step movement, a step cycle of which comprises a movement phase and a subsequent standstill phase. A first value for the angular velocity of the drive shaft is assumed at a first time in the movement phase of the step cycle and a second value different from the first value is assumed at a second time in the standstill phase of the same step cycle.

First claim

What is claimed is:

1. A hot forming machine, comprising:
a plurality of processing stations arranged in a circular manner and a rotary table arranged thereabove, in which glass tubes to be processed are held and movable from one processing station to the next by a stepwise rotary movement, the rotary table being connected on a drive side to a step gear which translates a movement of a drive shaft into a cyclic step movement, a step cycle of which comprises a movement phase and a subsequent standstill phase; and
a drive unit comprising:
a drive motor adapted to drive the drive shaft at a variable, predeterminable angular velocity; and
a control unit adapted to drive the drive shaft in such a manner that the angular velocity of the drive shaft assumes a first value at a first time in the movement phase of the step cycle and assumes a second value different from the first value at a second time in the standstill phase of the same step cycle.

2. The hot forming machine according to claim 1 , wherein the first value is higher than the second value.

3. The hot forming machine according to claim 1 , wherein the angular velocity is constant during the movement phase.

4. The hot forming machine according to claim 1 , wherein the angular velocity is constant during a time span within the standstill phase.

5. The hot forming machine according to claim 4 , wherein the time span comprises more than 60% of the standstill phase.

6. The hot forming machine according to claim 1 , wherein a plurality of step cycles immediately follow one another, an angular velocity curve of each step cycle being identical.

7. A drive unit for a hot forming machine having a plurality of processing stations arranged in a circular manner and a rotary table arranged thereabove, in which glass tubes to be processed are held and movable from one processing station to the next by a stepwise rotary movement, the rotary table being connected on a drive side to a step gear which translates a movement of a drive shaft into a cyclic step movement, a step cycle of which comprises a movement phase and a subsequent standstill phase, the drive unit comprising:
a drive motor adapted to drive the drive shaft at a variable, predeterminable angular velocity; and
a control unit adapted to drive the drive shaft in such a manner that the angular velocity of the drive shaft assumes a first value at a first time in the movement phase of the step cycle and assumes a second value different from the first value at a second time in the standstill phase of the same step cycle.

8. The drive unit according to claim 7 , wherein the drive motor is designed as a synchronous motor.

9. The drive unit according to claim 7 , wherein the step gear is designed as a cylinder cam gear.

10. A control unit for a rotary drive of a hot forming machine having a plurality of processing stations arranged in a circular manner and a rotary table arranged thereabove, in which glass tubes to be processed are held and movable from one processing station to the next by a stepwise rotary movement, the rotary table being connected on a drive side to a step gear which translates a movement of a drive shaft into a cyclic step movement, a step cycle of which comprises a movement phase and a subsequent standstill phase, the control unit being adapted to drive the drive shaft of the step gear with a variable angular velocity in such a manner that the angular velocity of the drive shaft assumes a first value at a first time in the movement phase of the step cycle and assumes a second value different from the first value at a second time in the standstill phase of the same step cycle.

11. A method for retrofitting a hot-forming machine with a plurality of processing stations arranged in a circular manner and a rotary table arranged thereabove, in which glass tubes to be processed are held and movable from one processing station to the next by a stepwise rotary movement, the rotary table being connected on a drive side to a step gear which translates a movement of a drive shaft into a cyclic step movement, a step cycle of which comprises a movement phase and a subsequent standstill phase, the method comprising:
retrofitting a control unit in the hot forming machine, the control unit being adapted to drive the drive shaft in such a manner that the angular velocity of the drive shaft assumes a first value at a first time in the movement phase of the step cycle and assumes a second value different from the first value at a second time in the standstill phase of the same step cycle.

12. The method according to claim 11 , further comprising retrofitting a drive motor for driving the drive shaft with a variable, predeterminable angular speed in the hot forming machine.

13. The method according to claim 12 , wherein the drive motor is designed as a synchronous motor.

Assignees

• Schott Schweiz Ag

Inventors

• Studerus Diego

Classifications

• C03B23/045 Primary

  Tools or apparatus specially adapted for re-forming tubes or rods in general, e.g. glass lathes, chucks (C03B23/043 takes precedence) · CPC title

• C03B23/112

  Apparatus for conveying the tubes or rods in a curved path around a vertical axis through one or more forming stations · CPC title

• C03B23/043

  Heating devices specially adapted for re-forming tubes or rods in general, e.g. burners · CPC title

• Y02P40/57

  Improving the yield, e-g- reduction of reject rates · CPC title

• F16H27/04 Primary

  for converting continuous rotation into a step-by-step rotary movement · CPC title