Diagnostic element for validation of bolt detection of a guard locking switch in a static state

Patent metadata

Field	Value
Publication number	US-11328548-B2
Application number	US-202017020912-A
Country	US
Kind code	B2
Filing date	Sep 15, 2020
Priority date	May 31, 2019
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

A system for sensing a position of a locking bolt of an industrial locking switch includes an inductive circuit, a converter, and a master controller. The inductive circuit includes an inductive coil and a capacitor electrically connected in parallel. The inductive coil is positioned to receive a locking bolt of an industrial locking switch when the locking bolt is transitioned to a lock position. The converter is configured to convert a frequency of a current signal on the inductive circuit to a digital frequency value. The master controller is configured to generate a bolt detection signal in response to determining that the digital frequency value changes by an amount equal to or substantially equal to a defined frequency shift corresponding to a frequency shift induced by the inductive coil in response to presence of the locking bolt within the inductive coil's magnetic field.

First claim

What is claimed is:

1. A locking switch, comprising:
one or more entry slots configured to receive a locking tongue;
a radio frequency identifier (RFID) tag attached to the locking tongue; and
a detection circuitry comprising one or more RFID coils, wherein each of the one or more RFID coils is attached to one of the one or more entry slots, wherein the detection circuitry is configured to:
generate a current signal through the one or more RFID coils; measure one or more modulations of the current signal; detect insertion of the locking tongue into one of the one or more entry slots based on the measurement; and generate a detection signal in response to the detection of insertion of the locking tongue into one of the one or more entry slots;
further comprising a locking bolt configured to engage with the locking tongue when advanced to a locking position; and
a control circuity configured to receive the detection signal and determine a position of locking bolt based at least in part on the detection signal.

2. The locking switch of claim 1 , wherein the one or more entry slots comprises: a first entry slot located on a first side of the locking switch, a second entry slot located on a second side of the locking switch, and a third entry slot located on a third side of the locking switch.

3. The locking switch of claim 2 , wherein the locking tongue is configured to insert in one of the first, the second, or the third entry slots.

4. The locking switch of claim 3 , wherein the one or more RFID coils comprises: a first RFID coil attached to the first entry slot, a second RFID coil attached to the second entry slot, a third RFID coil attached to the third entry slot.

5. The locking switch of claim 4 , wherein the first, the second, and the third RFID coils are electrically connected in series.

6. The locking switch of claim 1 , wherein the one or more RFID coils are mounted on a top surface of a bobbin mounted inside a housing of the locking switch, wherein the top surface of the bobbin is slanted relative to a bottom surface of the bobbin, wherein the top surface tilts the one or more RFID coils outward from a center of the bobbin.

7. A system for sensing a position of a locking bolt of an industrial locking switch, comprising:
an inductive circuit comprising an inductive coil and a capacitor electrically connected in parallel, wherein the inductive coil is positioned to receive a locking bolt of an industrial locking switch when the locking bolt is transitioned to a lock position;
a converter configured to convert a frequency of a current signal on the inductive circuit to a digital frequency value; and
a master controller configured to generate a bolt detection signal in response to determining that the digital frequency value changes by an amount equal to or substantially equal to a defined frequency shift corresponding to a frequency shift induced by the inductive coil in response to presence of the locking bolt within the inductive coil's magnetic field;
wherein the inductive coil is mounted in a central opening of a bobbin mounted inside a housing of the locking switch; and
an RFID coil is mounted on a top surface of the bobbin that is slanted relative to a bottom surface of the bobbin, and the top surface tilts the at least one RFID coil relative to the inductive coil.

8. The system of claim 7 , wherein
the bobbin is oriented to cause the locking bolt to pass through the central opening and the inductive coil when the locking bolt is transitioned to the lock position.

9. The system of claim 8 , wherein a first operating frequency of the inductive coil is different than a second operating frequency of the radio frequency identifier (RFID) coil mounted on the bobbin and configured to detect insertion of a locking tongue into the locking switch.

10. The locking switch of claim 9 , wherein
the locking bolt comprises a first metal and the locking tongue comprises a second metal, and
the first metal causes the inductive coil to induce a greater frequency shift of the current signal than the second metal.

11. A method for detecting positions of a locking tongue of a locking switch, comprising:
one or more entry slots configured to receive a locking tongue;
a radio frequency identifier (RFID) tag attached to the locking tongue;
generating a current signal through an inductive sensing circuit attached to one of the one or more entry slots, in response to detecting that a locking tongue is advanced to a locking position, wherein the inductive sensing circuit comprises an inductive coil and a capacitor;
converting a frequency of the current signal to a digital frequency value;
determining whether a shift in the digital frequency value corresponds to an expected frequency shift of the current signal induced by the inductive coil in response to advancement of the locking tongue; and
generating a lock detection signal in response to determining that the shift in the digital frequency value corresponds to the expected frequency shift of the current signal;
further comprising a locking bolt configured to engage with the locking tongue when advanced to a locking position; and
a control circuity configured to receive the detection signal and determine a position of locking bolt based at least in part on the detection signal.

12. The method of claim 11 , further comprising:
generating a current signal through one or more radio frequency identifier (RFID) coils attached to one or more entry slots of the lock switch;
measuring one or more modulations of the current signal through the one or more RFID coils;
detecting insertion of the locking tongue into one of the one or more entry slots based on the measurement; and
generate a detection signal indicating that the lock tongue is advanced to the locking position in response to the detection of insertion of the locking tongue into one of the one or more entry slots.

13. The method of claim 11 , further comprising connecting a diagnostic capacitor in parallel with the capacitor of the inductive sensing circuit.

14. The method of claim 13 , wherein the connecting comprises enabling a diagnostic switch that electrically connects the diagnostic capacitor to the inductive sensing circuit.

15. The method of claim 13 , wherein the diagnostic capacitor has a capacitance that, in response to connection of the diagnostic capacitor to the inductive circuit in parallel with the capacitor, causes the frequency of the current signal to shift by the defined frequency shift.

16. The method of claim 13 , further comprising in response to determining that the frequency of the current signal through the inductive sensing circuit does not change, within a defined duration after the connecting of the diagnostic capacitor, by an amount equal to or substantially equal to a frequency shift caused by presence of the locking bolt in the inductive coil's magnetic field, generating an error message indicating that the inductive sensing circuit is not operating correctly.

17. The method of claim 16 , wherein the generating the error signal comprises sending the error signal to at least one of an industrial safety system or an industrial control system.

Assignees

• Rockwell Automation Tech Inc

Inventors

• Wolfe Timothy P
• Cai Yongyao

Classifications

• G07C9/28 Primary

  the pass enabling tracking or indicating presence · CPC title

• E05B2047/0094

  Mechanical aspects of remotely controlled locks · CPC title

• H03K17/9545

  with variable frequency · CPC title

• F16P3/08

  in connection with the locking of doors, covers, guards, or like members giving access to moving machine parts · CPC title

• H03K17/9502

  Measures for increasing reliability · CPC title