Control system for an unwinding roll

• US 4,151,403 A
• Filed: 10/05/1977
• Issued: 04/24/1979
• Est. Priority Date: 10/05/1977
• Status: Expired due to Term

• Current Assignee: Molins Machine Company Incorporated (MPAC Group PLC)
• Original Assignee: Molins Machine Company Incorporated (MPAC Group PLC)
• Inventors: Woolston, Allan B.
• Primary Examiner(s): Thesz, Joseph M.
• Application Number:
  US05/839,680
• Time in Patent Office: 566 Days
• Field of Search: 235/92 DN, 235/92 CT, 235/92 CP, 235/92 DP, 242/186, 242/57, 242/201, 242/58.1, 364/562, 364/468, 364/470
• US Class Current: 702/163
• CPC Class Codes: B65H 19/10 in unwinding mechanisms or in connection with unwinding operations
• CPC Class Codes: B65H 2301/41522 Detecting residual amount of web
• CPC Class Codes: B65H 2553/51 Encoders, e.g. linear
• CPC Class Codes: G01B 11/043 for measuring length

Abstract

An optical encoder generates a train of digital pulses as a function of the length of web material unwound per revolution of an unwinding roll. A counter counts the encoder pulses for each revolution of the roll. The counts of the encoder pulses are accumulated over a first set of revolutions of the roll. A programmed microprocessor effects a base computation of (1) the average change in the number of pulses generated per revolution of the roll and (2) the length of web remaining on the roll after the first set of revolutions. Thereafter, the base computation of web length is updated at each revolution of the roll. The counter may comprise an addressable hardware counter chain alone or in combination with a read/write memory which counts the number of times that the counter chain overflows.

Claims

1. Apparatus for determining the length of web remaining on an unwinding roll, comprising:

first means for generating a train of digital pulses representative of the length of web unwound per revolution of the roll;

second means for monitoring the number of revolutions of the roll;

third means operatively associated with said first and second means for accumulating successive counts of said pulses over a predetermined number of revolutions of the roll;

fourth means operatively associated with said first, second and third means for computing the average change in the number of said pulses generated per revolution of the roll over a predetermined number of revolutions of the roll and for computing the length of web remaining on the roll after each revolution thereof based on said computed average change and the accumulated counts of said pulses.

2. The apparatus according to claim 1 wherein said third means comprises an addressable hardware counter chain.

3. The apparatus according to claim 1 wherein said fourth means includes a programmed microprocessor.

4. The apparatus according to claim 3 wherein said microprocessor includes means for detecting whether said computed length of web is less than a preselected length.

5. The apparatus according to claim 1 wherein said fourth means includes means for detecting overflow of said counter chain and a read/write memory for counting the number of times overflow of said counter chain is detected.

6. A control system for a mechanism operatively associated with an unwinding roll of web material, comprising:

first means for measuring the length of web unwound per revolution of the roll;

second means for monitoring the number of revolutions of the roll;

third means operatively associated with said first and second means for summing the measurements of web length over a predetermined number of revolutions of the unwinding roll;

fourth means operatively associated with said first, second and third means for computing the average change in the measurements of web length per revolution of the unwinding roll over a predetermined number of revolutions of the roll and for computing the length of web remaining on the roll after each revolution thereof based on said computed average change and the summed measurements of web length; and

fifth means operatively associated with said fourth means for actuating the mechanism.

7. The control system according to claim 6 wherein said third means includes an addressable hardware counter chain.

8. The control system according to claim 6 wherein said fourth means includes a programmed microprocessor.

9. The control system according to claim 8 wherein said microprocessor includes means for detecting whether said computed length of web is less than a preselected length.

10. The control system according to claim 6 wherein said fourth means includes means for detecting overflow of said second means and a read/write memory for counting the number of times overflow of said second means is detected.

11. An automatic splice control system for a web splicer apparatus which includes at least one running web roll and one ready web roll and a splice mechanism for splicing the running web to the ready web, comprising:

a sensor for generating a digital signal per revolution of the running roll;

an encoder operatively associated with the running web for generating a train of digital pulses representative of the length of web unwound per revolution of the running roll;

a counter operatively associated with said sensor and said encoder for accumulating successive counts of said encoder pulses over a predetermined number of revolutions of the running roll;

a programmed microprocessor operatively associated with said counter for computing the average change in the number of said encoder pulses generated per revolution of the running roll over a predetermined number of revolutions of the roll and for computing the length of web remaining on the roll after each revolution thereof based on said computed average change and said accumulated count; and

means operatively associated with said microprocessor for causing the splicer apparatus to initiate a splice sequence wherein the running web is spliced to the ready web.

12. The automatic splice control system according to claim 11 wherein said counter comprises an adjustable counter chain connected to said encoder and said microprocessor includes a random access memory for counting the number of times said counter chain overflows.

13. A method of determining the length of web remaining on an unwinding roll, comprising:

generating a train of digital pulses representative of the length of web unwound per revolution of the roll;

monitoring the number of revolutions of the roll;

accumulating successive counts of said pulses over a predetermined number of revolutions of the roll;

computing the average change in the number of said pulses generated per revolution of the roll over a predetermined number of revolutions of the roll; and

computing the length of web remaining on the roll after each revolution thereof based on said computed average change and the accumulated counts of said pulses.

14. The method according to claim 13 including detecting whether said computed length of web is less than a preselected length.

15. A method of controlling a mechanism operatively associated with an unwinding roll of web material, comprising:

measuring the length of web unwound per revolution of the unwinding roll;

monitoring the number of revolutions of the roll;

summing the measurements of web length over a predetermined number of revolutions of the unwinding roll;

computing the average change in the measurements of web length per revolution of the unwinding roll over a predetermined number of revolutions of the roll;

computing the length of web remaining on the roll after each revolution thereof based on said computed average change and the summed measurements of web length; and

actuating the operating mechanism as a function of the computation of length of web remaining on the roll.

16. The method according to claim 15 wherein said actuating step includes detecting whether said computed length of web is less than a preselected length.

17. A method of controlling a web splicer apparatus which includes at least one running web roll and one ready roll and a splice mechanism for splicing the running web to the ready web, comprising:

generating a digital signal per revolution of the running roll;

generating a train of digital pulses representative of the length of web unwound per revolution of the running roll;

accumulating successive counts of the pulses over a predetermined number of revolutions of the running roll;

computing the average change in the number of the pulses generated per revolution of the running roll over a predetermined number of revolutions of the roll;

computing the length of web remaining on the roll after each revolution thereof based on the computed average change and the accumulated counts of pulses; and

causing the splicer apparatus to initiate a splice sequence wherein the running web is spliced to the ready web when said computed length of web is less than a preselected value.