Detecting conductors in a cable-stripping process

Patent metadata

Field	Value
Publication number	US-10228339-B2
Application number	US-201314436497-A
Country	US
Kind code	B2
Filing date	Oct 3, 2013
Priority date	Oct 18, 2012
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

While stripping an electrical cable in a stripping device of a cable-processing system, detection by an electrically conductive cutting device with a sensor circuit takes place if contact with a conductor occurs. By connecting the sensor circuit to the cutting device a measuring capacitance is developed. Before incising the electrical cable, a capacitance value of the measurement capacitance is determined during a first measurement cycle in which a charge equalization is carried out between the measurement capacitance and a reference capacitance. A parameter is determined in a further measurement cycle in which a charge equalization is again carried out between the measurement capacitance and the reference capacitance, wherein, relative to the first capacitance, the parameter displays a change in the capacitance after incising into the electrical cable. A signal is produced, if the change is greater than an established threshold value, indicating contact with the conductor.

First claim

The invention claimed is:

1. A method for detecting contact of a conductor of an electric cable by an electrically conductive knife during a stripping process in a stripping device of a cable processing installation, wherein a sensor circuit is connected with the knife by a connection forming a measuring capacitance, the method comprising the steps of:
prior to cutting into the electric cable with the knife, determining a first capacitance value of the measuring capacitance during a first measuring cycle in which charge equalization between the measuring capacitance and a reference capacitance of a capacitance circuit of the sensor circuit is performed;
determining a parameter in a further measuring cycle in which charge equalization between the measuring capacitance and the reference capacitance is performed again, wherein the parameter indicates a change in a capacitance value of the measuring capacitance after the electric cable has been cut into by the knife; and
generating a signal if the change is greater than a fixed threshold value, wherein the signal indicates contact with the conductor by the knife;
wherein the first measuring cycle includes the following steps:
producing a defined voltage state at the measuring capacitance;
charging the reference capacitance so that a first voltage with a first voltage value is present at the capacitance circuit;
producing an electrical connection between the measuring capacitance and the reference capacitance enabling charge equalization between the measuring capacitance and the reference capacitance;
measuring a second voltage which is present at the reference capacitance after the charge equalization and which has a second voltage value; and
determining the first capacitance value of the measuring capacitance from the first and second voltage values and the reference capacitance;

including a further measuring cycle with the following steps:
producing the defined voltage state at the measuring capacitance;
charging the reference capacitance so that the first voltage is present at the capacitance circuit;
producing the electrical connection between the measuring capacitance and the reference capacitance enabling charge equalization between the measuring capacitance and the reference capacitance;
measuring the second voltage which is present at the reference capacitance after the charge equalization and which has the second voltage value; and
determining the parameter;

and wherein the first voltage value is measured in the first measuring cycle and is used in a further measuring cycle, and producing the defined voltage state includes coupling a defined voltage potential to the measuring capacitance.

2. The method according to claim 1 wherein during the stripping process a fixed number of further measuring cycles is carried out and wherein in each of the further measuring cycles determination of the parameter is referred to the first capacitance value from the first measuring cycle.

3. The method according to claim 1 wherein the first voltage value has a substantially constant value.

4. The method according to claim 1 wherein the parameter is a second capacitance value of the measuring capacitance and wherein the signal is generated when a difference between the first capacitance value and the second capacitance value exceeds a fixed capacitance threshold value.

5. The method according to claim 1 wherein the parameter is the second voltage value and wherein the signal is generated when a difference between the second voltage value of the first measuring cycle and the second voltage value of the further measuring cycle exceeds a fixed voltage threshold value.

6. The method according to claim 1 wherein producing the defined voltage state includes short-circuiting the measuring capacitance.

7. The method according to claim 1 wherein producing the defined voltage state includes closing a second switch in parallel with the measuring capacitance when an open first switch separates the reference capacitance from the measuring capacitance.

8. The method according to claim 7 wherein charging the reference capacitance includes closing a third switch between the reference capacitance and a voltage source when the second switch is opened.

9. The method according to claim 8 wherein producing the electrical connection comprises closing the first switch, opening the second switch and opening the third switch.

10. The method according to claim 7 wherein all of the switches are opened before a switching process is carried out.

11. The method according to claim 1 wherein when the signal is generated the knife is readjusted and wherein a spacing of the knife from the electric cable containing the conductor is changed.

12. The method according to claim 1 including in response to the signal being generated performing at least one of generating a warning tone, stopping of the stripping process, depositing of the electric cable in a special deposit and performing a statistical analysis.

13. A cable processing insulating device with a stripping device for carrying out the method for detecting conductor contact by the electrically conductive knife in a stripping process according to claim 1 .

14. The method according to claim 1 including a step of connecting a first connection of the sensor circuit to the knife and connecting a second connection of the sensing circuit to a reference potential whereby the measuring capacitance is a sum of all capacitances present between the first connection and the second connection.

15. A method for detecting contact of a conductor of an electric cable by an electrically conductive knife during a stripping process in a stripping device of a cable processing installation, wherein a sensor circuit is connected with the knife by a connection forming a measuring capacitance, the method comprising the steps of:
prior to cutting into the electric cable with the knife, determining a first capacitance value of the measuring capacitance during a first measuring cycle in which charge equalization between the measuring capacitance and a reference capacitance of a capacitance circuit of the sensor circuit is performed;
determining a parameter in a further measuring cycle in which charge equalization between the measuring capacitance and the reference capacitance is performed again, wherein the parameter indicates a change in a capacitance value of the measuring capacitance after the electric cable has been cut into by the knife;
generating a signal if the change is greater than a fixed threshold value, wherein the signal indicates contact with the conductor by the knife;
wherein the first measuring cycle includes the following steps:
producing a defined voltage state at the measuring capacitance;
charging the reference capacitance so that a first voltage with a first voltage value is present at the capacitance circuit;
producing an electrical connection between the measuring capacitance and the reference capacitance enabling charge equalization between the measuring capacitance and the reference capacitance;
measuring a second voltage which is present at the reference capacitance after the charge equalization and which has a second voltage value; and
determining the first capacitance value of the measuring capacitance from the first and second voltage values and the reference capacitance;

including a further measuring cycle with the following steps:
producing the defined voltage state at the measuring capacitance;
charging the reference capacitance so that the first voltage is present at the capacitance circuit;
producing the electrica

Assignees

• Komax Holding Ag

Inventors

• Zemp Benno

Classifications

• H02G1/1253

  making a transverse cut · CPC title

• H02G1/1202

  by cutting and withdrawing insulation · CPC title

• H02G1/1209

  making a transverse cut · CPC title

• H01R43/28 Primary

  for wire processing before connecting to contact members, not provided for in groups H01R43/02 - H01R43/26 · CPC title

• G01N27/22 Primary

  by investigating capacitance · CPC title