Patent Description:
It is the object of the present invention to allow an RFID tag of a tongue to be detected before the tongue is fully inserted into an entry slot of the housing of a locking switch.

The following presents a simplified summary in order to provide a basic understanding of some aspects described herein. This summary is not an extensive overview nor is intended to identify key/critical elements or to delineate the scope of the various aspects described herein. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

In one or more embodiments, an industrial locking system is provided, comprising an actuator assembly comprising a locking tongue, the locking tongue comprising an engagement hole; and a locking switch comprising: a housing comprising at least three entry slots configured to receive the locking tongue from respective at least three directions of approach, and a solenoid-driven locking bolt configured to engage with the engagement hole while the locking tongue is inserted into any one of the at least three entry slots.

Also, a system for locking industrial safety guarding is provided, comprising a locking switch comprising at least three entry slots formed on respective at least three adjacent sides of a housing of the locking switch; and an actuator assembly comprising a locking tongue configured to be received by any entry slot of the at least three entry slots, wherein the locking switch further comprises a solenoid-actuated locking bolt configured to, in response to advancement of the locking bolt while the locking tongue is inserted into any entry slot of the at least three entry slots, engage with an engagement hole formed on the locking tongue.

Also, a locking switch is provided, comprising a housing comprising three or more entry slots, wherein each of the three or more entry slots is configured to receive a locking tongue; and a solenoid-driven locking bolt inside the housing and configured to engage with an engagement hole formed in the locking tongue in response to advancing to a locked position while the locking tongue is inserted into any one of the three or more entry slots.

To the accomplishment of the foregoing and related ends, certain illustrative aspects are described herein in connection with the following description and the annexed drawings. These aspects are indicative of various ways which can be practiced, all of which are intended to be covered herein. Other advantages and novel features may become apparent from the following detailed description when considered in conjunction with the drawings.

The subject disclosure is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. It may be evident, however, that the subject disclosure can be practiced without these specific details.

Furthermore, the term "set" as employed herein excludes the empty set; e.g., the set with no elements therein. Thus, a "set" in the subject disclosure includes one or more elements or entities. As an illustration, a set of controllers includes one or more controllers; a set of holes includes one or more holes; etc..

Various aspects or features will be presented in terms of systems that may include a number of devices, components, modules, and the like. It is to be understood and appreciated that the various systems may include additional devices, components, modules, etc. and/or may not include all of the devices, components, modules etc. discussed in connection with the figures. A combination of these approaches also can be used.

Many industrial machines, robots, or automation systems are protected by safety guarding or fencing that surrounds the hazardous area, forming a protected cell. This safety fencing typically includes a lockable safety gate to allow operator access to the protected area only while the machine or system is not operating and is otherwise in a safe state. Solenoid-driven locking switches are often used to lock these safety gates in the closed position while the protected machine or system is operating in automatic mode and all associated safety devices are in their safe statuses, thereby preventing operator access to the hazardous area while the machine is running.

<FIG> is a perspective view of an example locking switch <NUM> and corresponding locking tongue <NUM>. The locking switch <NUM> is typically mounted to either the frame on which the gate is mounted or on the gate itself. The corresponding locking tongue <NUM> is mounted on the opposite gate component (either on the gate or on the frame) such that the tongue <NUM> aligns with an entry slot <NUM> on the locking switch <NUM>. The locking tongue <NUM> is generally ring-shaped, having a square or circular engagement hole <NUM> configured to receive and engage with the switch's internal solenoid-driven locking bolt when the bolt is advanced (not shown in <FIG>).

When the gate is in the closed position, the locking tongue <NUM> is received in the entry slot <NUM> of the locking switch <NUM>. While the protected machine or automation system is in automatic mode or is running, the locking switch <NUM> actuates a solenoid-driven locking bolt upward through the engagement <NUM> of the locking tongue <NUM>, preventing removal of the locking tongue <NUM> from the locking switch <NUM> and thereby preventing the gate from being opened. Some locking switches <NUM> are electrically connected to the machine cell's safety system such that the machine or automation system cannot be placed in automatic mode unless the locking tongue <NUM> is engaged with the locking switch <NUM>.

Example locking switch <NUM> comprises a main body <NUM> that houses the solenoid and retractable bolt (while retracted) and a attached head <NUM> on which the entry slot <NUM> is formed. Head <NUM> is removably attached to the body <NUM> and can be attached to the body <NUM> in a selected rotational orientation so that the entry slot <NUM> faces a selected one of three or four possible directions oriented at <NUM> increments.

In some installation scenarios, an installer or engineer may not have a priori knowledge of the direction from which the tongue <NUM> will approach the locking switch <NUM>, which may depend on the available mounting options for the tongue <NUM> and the switch <NUM>. In other scenarios, even if the direction of approach is known, it may be necessary to rotate the switch <NUM>, or to rotate the head <NUM> relative to the switch, so that the entry slot <NUM> faces the direction from which the tongue <NUM> will approach. The structural parameters of the locking switch <NUM> can limit available mounting options, or may require a labor-intensive mechanical reconfiguration of the locking switch <NUM> in order to accommodate the requirements of a given mounting scenario.

To address these and other issues, one or more embodiments described herein provide a locking switch configured to accommodate multiple directions of approach of a corresponding locking tongue <NUM> without the need to rotate the head, body, or switch as a whole. To facilitate detection of the tongue from each of these multiple directions, multiple radio frequency identifier (RFID) coils are also installed in the head of the sensor, each of which is capable of detecting an RFID tag on the tongue when the tongue has been inserted into an entry slot.

<FIG> are right side, front, and left side views of an example locking switch <NUM> according to one or more embodiments. <FIG> is a perspective close-up view of the top of locking switch <NUM>. Similar to example switch <NUM>, locking switch <NUM> comprises a main body <NUM> that houses the solenoid, locking bolt mechanism, and other electrical and electronic components. A cable port <NUM> is formed on the body housing <NUM> to receive power and signal cabling that interfaces with the switch's internal circuitry. Switch <NUM> also comprises a head <NUM> mounted to the main body <NUM>. In contrast to head <NUM> of switch <NUM>, head <NUM> comprises three entry slots 204a, 204b, and 204c. A first entry slot 204b is formed on a front side of head <NUM>, while entry slots 204a and 204c are formed on the right and left sides of head <NUM>, respectively. This configuration supports three orthogonal directions of approach of a corresponding locking tongue without the need to rotate the head <NUM> relative to the body <NUM>, or to rotate the switch <NUM> as a whole.

Embodiments of locking switch <NUM> can include detection circuitry that detects when the tongue has been inserted into any of the three entry slots 204a, 204b, or 204c, indicating that the locking bolt can be advanced in order to properly engage with the locking tongue. In some embodiments, this detection circuity can control an output signal (e.g. sent via a cable installed through cable port <NUM>) that indicates whether the locking tongue is inserted into one of the entry slots 204a, 204b, or 204c. In some implementations, this output signal may be used to control when the locking bolt transitions from the retracted (unlocked) position to the advanced (locked) position.

<FIG> is a perspective view of an example actuator assembly <NUM> that can be used with locking switch <NUM>, and which includes an RFID tag <NUM> that can be detected by RFID coils housed in the switch <NUM> (to be discussed in more detail below). Actuator assembly <NUM> comprises a base <NUM> in which is mounted a locking tongue <NUM> (or locking key) configured to engage with any of the entry slots 204a. 204b, or 204c of locking switch <NUM>. Mounting holes <NUM> are formed through base <NUM> and can be used in connection with mounting hardware to mount the actuator assembly <NUM> to a structure (e.g., the frame on which a safety gate is mounted or the gate itself).

Locking tongue <NUM> is formed on one end of an actuating shaft <NUM>, and the other end of actuating shaft <NUM> is installed within a recess <NUM> of base <NUM>. In the example depicted in <FIG>, tongue <NUM> has formed therein a substantially square bolt engagement hole <NUM> configured to receive the locking switch's locking bolt when the bolt is advanced, although bolt engagement holes of other shapes are also within the scope of one or more embodiments. RFID tag <NUM> is mounted in the tongue <NUM> within a circular mounting feature (e.g., a hole or recess) formed in the tongue <NUM> adjacent to the bolt engagement hole <NUM>. When tongue <NUM> is inserted within any of the entry slots 204a, 204b, or 204c, RFID coils mounted in the locking switch's head <NUM> can detect the presence of the RFID tag <NUM> and thereby confirm that the tongue <NUM> is inserted into the locking switch <NUM> and that the locking bolt can be engaged.

<FIG> is a perspective view of the top of locking switch <NUM> with the casing of head <NUM> removed, revealing a bushing <NUM> within which is housed the solenoid-driven locking bolt that, when advanced, engages with the inserted tongue <NUM>. A coil housing <NUM> is mounted above the locking bolt bushing <NUM> on the ceiling <NUM> of locking switch <NUM>. <FIG> is a perspective view of the top of locking switch <NUM> with both the casing of head <NUM> and the coil housing <NUM> removed. Enclosed within the coil housing <NUM> are three RFID coils <NUM> electrically connected in series, each coil <NUM> corresponding to a different one of the three entry slots 204a, 204b, and 204c. When head <NUM> is in place, each coil <NUM> is oriented above one of the entry slots 204a, 204b, and 204c to facilitate detection of the tongue's RFID tag <NUM>. The series-connected RFID coils <NUM> are components of a detection circuit housed in the locking switch <NUM>, which controls an output signal based on detection of the presence of the RFID tag <NUM>.

As shown in <FIG>, RFID coils <NUM> are mounted on bobbin <NUM>, which is mounted to the ceiling <NUM> of the locking switch <NUM>. <FIG> is a perspective, cross-sectional view of a bobbin assembly <NUM> comprising bobbin <NUM> and coils 506a, 506b, and 506c. Bobbin <NUM> has a substantially round profile and a top surface (or coil mounting surface) that slants upward from its edge to its center, yielding a top surface having a degree of tilt θ relative to the bottom surface (that is, the surface that mounts to the locking switch's housing). In an example embodiment θ may be approximately <NUM> degrees. However, other degrees of tilt are also within the scope of one or more embodiments. An opening <NUM> is formed in the center of bobbin <NUM> and is configured to receive the locking bolt when the bolt is advanced.

RFID coils 506a, 506b, and 506c are mounted on the slanted top surface of bobbin <NUM>. As a result, when bobbin <NUM> is mounted in the locking switch <NUM>, each RFID coil <NUM> is tilted relative to the plane of the ceiling <NUM> such that the coil's axis - and consequently the coil's sensing field - is directed outward from the center of the bobbin <NUM>. Tilting the RFID coils <NUM> in this manner can increase the lateral sensing distance of each RFID coil <NUM>, allowing the tongue's RFID tag <NUM> to be detected before the tongue <NUM> is fully inserted into the entry slot <NUM>. This feature, together with the relatively large size of the tongue's engagement hole <NUM>, can promote a large degree of mechanical freedom when aligning the engagement hole with locking bolt, as discussed in more detail below.

<FIG> is a cross-sectional top view of locking switch <NUM> with the tongue <NUM> of actuator assembly <NUM> inserted into the front facing entry slot 204b. <FIG> is a perspective view depicting relative positions of the actuator assembly <NUM> and RFID coils 506a, 506b, and 506c when the tongue <NUM> is inserted into the front facing entry slot 204b (for clarity, <FIG> and <FIG> depict RFID coils <NUM> as being oriented to reside in the same plane rather than being tilted; however, in claimed embodiments the RFID coils <NUM> will be tilted by bobbin <NUM> as shown in <FIG> and <FIG>). As shown in these figures, bolt engagement hole <NUM> aligns with the locking bolt <NUM> and RFID tag <NUM> resides below RFID coil <NUM> while tongue <NUM> is inserted into the entry slot <NUM>. RFID coils 506a, 506b, and 506c are connected in series and are electrically driven by detection circuitry <NUM> inside the sensor's housing to generate three separate electromagnetic fields. This detection circuitry <NUM> includes an RFID transceiver that detects disturbances to any of the three electromagnetic fields due to the presence of RFID tag <NUM> within range of the electromagnetic field. Such disturbances modulate an RFID current signal into the detection circuitry <NUM>, which detects the presence of the tongue <NUM> based on these current signal modulations.

Since RFID coils 506a, 506b, and 506c are connected in series, disturbances to any of the three electromagnetic fields generated by the respective three coils <NUM> are detected by the RFID transceiver of detection circuitry <NUM>. Thus, a single RFID transceiver can be used to detect entry of the tongue <NUM> into any of the three entry slots 204a, 204b, and 204c, mitigating the need for three separate RFID transceivers. This configuration can also yield a relatively fast response time, since the tongue's RFID tag <NUM> can be detected from multiple directions by monitoring only one signal, without the need to multiplex signals or analyze multiple signal lines. In some embodiments, the middle RFID coil 506b can be flipped in polarity relative to the polarities of RFID coils 506a and 506c, partially cancelling the magnetic field in the center of coil <NUM> and reducing interference of the RFID signal on the bolt detection signal.

<FIG> is a top view of an example tongue component <NUM> that can be used in the actuator assembly <NUM> to prevent premature detection due to parasitic effects. As shown in this figure, tongue component <NUM> comprises a gap <NUM> that runs from the edge of RFID tag mounting hole <NUM> (in which the RFID tag <NUM> resides) through the entire length of the articulating shaft <NUM>, splitting the articulating shaft <NUM> along its lengthwise axis. Gap <NUM> is designed to mitigate potential parasitic effects of the metal tongue component <NUM> that could otherwise cause the tongue <NUM> to act as an antenna in the presence of the RFID coils' magnetic fields, resulting in premature detection of the tongue <NUM> before the tongue is inserted to a viable locking depth.

This electrical configuration, together with the mechanical design of the locking switch's head <NUM>, affords a degree of installation flexibility by supporting three different directions of approach of the tongue <NUM> without the need to rotate head <NUM> or, in some cases, to re-orient the locking switch as a whole. This arrangement is supported by an electrical detection system that can detect entry of the tongue <NUM> from any of the multiple directions by monitoring a single electrical signal with one sensor.

As noted above, RFID coils <NUM> are tilted outward by virtue of the slanted surface of bobbin <NUM> (see <FIG>). This extends the sensing distance of each RFID coil <NUM> and allows the detection circuitry <NUM> to detect the tongue's RFID tag <NUM> before the tongue <NUM> is fully inserted into an entry slot <NUM>. This extended detection distance can work in conjunction with an engagement hole <NUM> that is sized to be considerably larger than the locking bolt <NUM> to introduce a large degree of misalignment tolerance between the tongue <NUM> and the locking bolt <NUM>. That is, sizing the tongue's engagement hole <NUM> to be larger than the cross-sectional profile of the locking bolt <NUM> allows the locking bolt <NUM> to successfully engage with the tongue's engagement hole across a larger range of tongue insertion depths than would be possible if the engagement hole <NUM> was sized more closely to the locking bolt's profile. Since this design does not require the tongue <NUM> to be fully inserted into an entrance slot <NUM> before the locking bolt <NUM> can be engaged, the extended sensing distance that results from tilting of the RFID coils <NUM> as shown in <FIG> can facilitate detection of the RFID tag <NUM> at the earliest insertion position at which the locking bolt <NUM> can be safely advanced while ensuring reliable engagement with the engagement hole <NUM>.

In some embodiments, a further degree of misalignment tolerance between the tongue <NUM> and the locking switch <NUM> can be achieved by designing the actuator assembly <NUM> such that the tongue <NUM> can articulate within the base <NUM> to a limited degree. Returning to <FIG>, tongue <NUM> is formed on one end of an articulating shaft <NUM> that is mounted within a recess <NUM> of base <NUM>. The shaft <NUM> is unrestrained in the x-y plane (that is, the plane parallel with the front face of the base <NUM>), allowing the shaft <NUM> and tongue <NUM> to pivot away from its normal axis relative to base <NUM> within the bounds of recess <NUM>. In some embodiments, the shaft <NUM> may also be afforded limited sliding movement along the z-axis (perpendicular to the face of base <NUM>). Designing the actuator assembly <NUM> to permit a limited degree of tongue articulation in this manner further increases the misalignment tolerance between the tongue <NUM> and the locking switch <NUM>. allowing the tongue <NUM> to be inserted into an entry slot <NUM> and engaged with the locking bolt <NUM> even if the tongue <NUM> is imperfectly aligned with these switch components.

Returning now to <FIG>, some embodiments of bobbin assembly <NUM> may also include an inductive coil <NUM> mounted within the opening <NUM> of the bobbin <NUM>. Coil <NUM> is part of an LC tank circuit housed within the switch housing used to detect and confirm that the locking bolt <NUM> has been advanced. <FIG> is a cross-sectional view of the locking switch's head <NUM> with actuator assembly <NUM> inserted and engaged with the locking switch. For clarity, the bobbin <NUM> is omitted from this view to illustrate the positions of RFID coils <NUM> and inductive coil <NUM>. An LC tank circuit including inductive coil <NUM> in parallel with a capacitor (not shown in <FIG>) acts as an inductive sensor that detects when the locking bolt <NUM> is in the advanced position. For example, the circuit can drive an alternating current through the coil <NUM>, where the frequency of the current is a function of the inductance of the coil <NUM>. Inductive coil <NUM> resides along the edge of the bobbin's central opening <NUM> so that locking bolt <NUM> passes through the coil <NUM> when advanced to the locked position. While locking bolt <NUM> is in the advanced (locked) position, the presence of the metal locking bolt <NUM> within the coil's magnetic field changes the inductance of the coil <NUM>, and thus changes the frequency of the current signal. This change in the frequency of the current signal is detected by the LC tank circuit which generates a confirmation signal in response, indicating that the locking bolt <NUM> is in the advanced position. Thus, inductive coil <NUM> and its associated LC tank circuit provide a noncontact method for confirming that locking bolt <NUM> has properly advanced and engaged with tongue <NUM>. The use of an inductive sensor allows the position of locking bolt <NUM> to be detected without the use of a magnet or optical sensing, yielding a robust solution for bolt detection.

For embodiments of locking switch <NUM> that include both inductive coil <NUM> for detecting the locking bolt <NUM> and RFID coils <NUM> detecting the locking tongue <NUM>, different types of metal can be used for the tongue <NUM> and the bolt <NUM> to ensure that the inductive coil <NUM> reliably detects locking bolt <NUM> without detecting the locking tongue <NUM>. In general, the metal used to fabricate the locking bolt <NUM> can be chosen as one having intrinsic properties that cause the inductive coil <NUM> to induce a greater frequency shift than those of the metal chosen for the locking tongue <NUM>. In an example embodiment, locking tongue <NUM> can be made of <NUM> series stainless steel (e.g., <NUM>, <NUM>, etc.), while locking bolt <NUM> can be made from <NUM> series stainless steel. <FIG> is a graph <NUM> that plots sensor inductance shift as a function of sensor frequency for a variety of materials. The amount of sensor inductance shift is a function of intrinsic properties of the respective materials. The horizontal line <NUM> represents the lack of frequency shift when no metal is present (free space). The top line <NUM> represents the inductance shift of stainless steel <NUM>, line <NUM> represents the inductance shift of stainless steel <NUM>, and the bottom line represents the inductance shift of aluminum <NUM>. If stainless steel <NUM> and stainless steel <NUM> are chosen as the materials for locking tongue <NUM> and locking bolt <NUM>, respectively, the relative inductance shifts modeled by graph <NUM> can be used to find an operating frequency for the inductive sensor (including inductive coil <NUM>) that maximizes detection of locking bolt <NUM> while minimizing detection of the locking tongue <NUM>; e.g., by selecting a sensor operating frequency corresponding to a sufficiently large inductance shift for stainless steel <NUM> (line <NUM>) to ensure reliable detection of the locking bolt <NUM>, and a sufficiently small inductance shift for stainless steel <NUM> (line <NUM>) to ensure that the locking tongue <NUM> is not detected by the inductive sensor.

Also, for embodiments in which both inductive coil <NUM> and RFID coils <NUM> are included in the same locking switch, the tilting of the RFID coils <NUM> due to the slanted surface of bobbin <NUM> can minimize the risk of interference between the RFID coils <NUM> and inductive coil <NUM>, since the RFID coils are tilted relative to the inductive coil causing the sensing fields of the RFID coils to be directed away from that of the inductive coil. In some embodiments, the RFID coils <NUM> and inductive coil <NUM> can be operated at different operating frequencies (e.g., <NUM> for the inductive coil <NUM> and <NUM> for the RFID coils <NUM>) to further minimize the risk of interference between the two sensing systems.

Industrial safety applications can be made more robust if their associated locking switches are capable of validating proper operation of their locking bolts. This can include validating that the locking switch is capable of reliably confirming the actual position of the locking bolt. Some locking switches may perform this validation by advancing the locking bolt to the locked position and then retracting the bolt back to the unlocked position during a test sequence, and confirming that the bolt detection signal was properly received. However, since this validation approach requires the locking bolt to be actuated, normal operation of the switch must be interrupted in order to validate locking bolt detection. If the locking switch is currently holding a safety gate in the closed and locked position, actuating the locking bolt during this test sequence causes the safety gate to become temporarily unlocked, creating a potential safety hazard.

To address this issue, one or more embodiments of locking switch <NUM> can include validation circuitry that validates operation of the lock detection signal without requiring the locking bolt <NUM> to be actuated or otherwise interrupting the functionality of the locking switch <NUM>. <FIG> is a generalized diagram of an example validation circuit that includes diagnostic circuitry capable of confirming the locking switch's bolt detection capability without interrupting the function of the switch <NUM>. In this example, the LC tank circuit <NUM> used to detect the locking bolt <NUM> while in its advanced (locking) position comprises the inductive coil <NUM> (which can mounted in bobbin <NUM> in some embodiments, as discussed above) and a capacitor <NUM> connected in parallel. An inductance-to-digital converter (LDC) <NUM> (or another type of conversion component) is connected to the nodes of LC tank circuit <NUM> and translates the measured frequency of the current signal generated by the LC circuit <NUM> to digital data that is placed on a data bus <NUM> (e.g., an I2C bus or another type of data bus). This frequency signal is indicative of the inductance of coil <NUM>, which in turn is a function of the presence or absence of locking bolt <NUM> within the magnetic field of inductive coil <NUM>. Although <FIG> depicts an LDC <NUM> as the conversion component used to translate the current signal frequency to digital data, other types of conversion components can also be used to generate a digital value proportionate to the current signal frequency in some embodiments.

A master controller <NUM> on the data bus <NUM> monitors the digital frequency signal on the data bus <NUM> and confirms that the locking bolt <NUM> has properly advanced - or has properly retracted - based on measured changes to the digital frequency value. For reliability purposes, some embodiments may also include a watchdog controller <NUM> that is tied to the data bus <NUM> and performs redundant monitoring of the digital frequency signal. In some embodiments, both the master controller <NUM> and the watchdog controller <NUM> may perform parallel independent monitoring of the digital frequency signal and collectively confirm the position of the locking bolt <NUM> only if both controllers <NUM> and <NUM> reach the same conclusion. In some embodiments, the master controller <NUM> and/or the watchdog controller generates a confirmation signal in response to this confirmation that the locking bolt <NUM> has advanced.

To verify that this locking bolt validation system is reliably monitoring and reporting the state of the locking bolt, a diagnostic capacitor <NUM> is connected to the LC tank circuit <NUM> via a diagnostic switch <NUM> (e.g., a solid state switching device). Diagnostic capacitor <NUM> remains isolated from the LC tank circuit <NUM> while the diagnostic switch <NUM> is disabled. During a diagnostic sequence initiated and controlled by the master controller <NUM>, the diagnostic switch <NUM> is enabled (e.g., by a signal applied to the diagnostic switch's Enable input by master controller <NUM>), which causes the diagnostic capacitor <NUM> to be electrically connected to the LC tank circuit <NUM> in parallel with capacitor <NUM>. The capacitance of diagnostic capacitor <NUM> is sized such that connecting the diagnostic capacitor <NUM> in parallel with tank capacitor <NUM> creates a shift in the frequency of the current signal through the LC tank circuit <NUM> that is roughly the equivalent of the frequency shift caused by the presence of the locking bolt <NUM> within the magnetic field of coil <NUM>. That is, whereas advancement of locking bolt <NUM> to the locked position changes the inductance of coil <NUM> in a manner that alters the frequency of the current through the LC tank circuit <NUM> by a predictable frequency shift magnitude, connecting diagnostic capacitor <NUM> to the LC tank circuit <NUM> (by enabling diagnostic switch <NUM>) changes the capacitance of the LC tank circuit <NUM> in a manner that alters the frequency by a substantially equal frequency shift magnitude.

During the diagnostic sequence, master controller <NUM> can enable the diagnostic switch <NUM> and monitor the digital frequency value generated by the LDC <NUM> to verify that the frequency value changes as expected. For example, during normal operation of the locking switch <NUM> the master controller <NUM> can monitor the digital frequency value on bus <NUM> and, in response to determining that the frequency value changes by a defined frequency shift magnitude indicative of the presence of the locking bolt within the coil's magnetic field, generate a confirmation signal indicating that the locking bolt <NUM> has been advanced. The defined frequency shift magnitude may be defined as a valid frequency shift range to allow for small frequency variations.

During a diagnostic sequence, master controller <NUM> can enable diagnostic switch <NUM> and, in response to determining that the digital frequency value shifts by the defined frequency shift magnitude (within a defined tolerance) within an expected time duration after enabling the diagnostic switch <NUM>, confirm that the locking bolt validation system is operating properly and is capable of reliable detecting the state of the locking bolt <NUM>. Alternatively, if the master controller <NUM> determines that the digital frequency value has not shifted by the defined frequency shift magnitude within the defined time duration after enabling the diagnostic switch <NUM>, the master controller <NUM> generates an error signal. The error signal may include an error message rendered on a client device indicating that the locking bolt validation system is not working properly, or may be an error signal sent to an external safety or control system. This diagnostic sequence can be performed regardless of whether the locking bolt <NUM> is currently advanced or retracted, and does not require the locking bolt <NUM> to be physically actuated in order to validate the LC tank circuit <NUM> and its associated LDC <NUM>. During the diagnostic sequence, any control outputs from the locking switch <NUM> that would otherwise be generated in response to detecting that the locking bolt has been advanced are disabled to prevent false indications being sent to external control or safety systems.

In contrast to locking switches that employ two separate optical sensors to detect the locking bolt's lock and unlock positions, respectively, the use of an inductive sensor (LC tank circuit <NUM>) with associated diagnostic circuitry requires only a single sensor to confirm the position of the locking bolt <NUM> in a robust and reliable manner.

<FIG> is a generalized diagram of another example embodiment of locking bolt validation circuit including diagnostic circuitry. This example embodiment adds a separate diagnostic controller <NUM> so that operation of the master controller <NUM> and watchdog controller <NUM> is included in the scope of validation. In contrast to the embodiment depicted in <FIG>, the enable signal that controls the state of diagnostic switch <NUM> is generated by this new diagnostic controller <NUM> rather than by master controller <NUM>. Diagnostic controller <NUM> validates operation of the locking bolt detection circuitry by monitoring outputs of the master controller <NUM> and watchdog controller <NUM> rather than by monitoring the digital frequency signal directly as in the embodiment depicted in <FIG>.

In this embodiment, during the diagnostic sequence, diagnostic controller <NUM> enables switch <NUM> and monitors the detection signals generated master controller <NUM> and watchdog controller <NUM>. Each controller <NUM> and <NUM> generates its detection signal in response to detecting the expected shift in the digital frequency signal caused by switching the diagnostic capacitor <NUM> to the LC tank circuit <NUM>. If the detection signals from both the master controller <NUM> and watchdog controller <NUM> indicate that the expected frequency shift has been detected within a defined time duration after generating the enable signal, diagnostic controller <NUM> determines that the locking bolt detection circuitry is operating properly. Alternatively, if diagnostic controller <NUM> does not received one or both of the detection signals from the master controller <NUM> or the watchdog controller <NUM> within the defined time duration after initiating the enable signal, the diagnostic controller <NUM> determines that the locking bolt detection circuitry is not functioning properly and generates an error signal.

The various sensing and validation features described herein can be used collectively in a single locking switch in some embodiments. Other embodiments may comprise locking switches that incorporate only a subset of the disclosed sensing and validation features. For example, some embodiments of the disclosed locking switch <NUM> may include both RFID coils <NUM> and inductive coil <NUM>. Other embodiments may incorporate only the RFID coils <NUM> without including inductive coil <NUM>, while still other embodiments may include only the inductive coil <NUM> without including RFID coils <NUM>. Moreover, while embodiments of locking switch <NUM> have been described herein as including three locking tongue entry slots <NUM>, some embodiments may include more than three tongue entry slots <NUM> (and corresponding RFID coils <NUM>) without departing from the scope of one or more embodiments. Some embodiments may also comprise only two tongue entry slots <NUM> and corresponding RFID coils <NUM>.

<FIG> illustrate methodologies in accordance with one or more embodiments of the subject application. While, for purposes of simplicity of explanation, the methodologies shown herein are shown and described as a series of acts, it is to be understood and appreciated that the subject innovation is not limited by the order of acts, as some acts may, in accordance therewith, occur in a different order and/or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate that a methodology could alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all illustrated acts may be required to implement a methodology in accordance with the innovation. Furthermore, interaction diagram(s) may represent methodologies, or methods, in accordance with the subject disclosure when disparate entities enact disparate portions of the methodologies. Further yet, two or more of the disclosed example methods can be implemented in combination with each other, to accomplish one or more features or advantages described herein.

<FIG> is an example methodology <NUM> for detecting insertion of a locking tongue of an actuator assembly into an industrial locking switch from any of three different directions of approach. At <NUM>, a determination is made as to whether an RFID tag mounted on a locking tongue of an actuator assembly is detected by any of a first RFID coil located inside a first entry slot of an industrial locking switch, a second RFID coil located inside a second entry slot of the industrial locking switch, or a third RFID coil located inside a third entry slot of the industrial locking switch. If the RFID tag is not detected by any of the three RFID coils (NO at step <NUM>), step <NUM> repeats until any of the three RFID coils detects the RFID tag (YES at step <NUM>), causing the methodology to proceed to step <NUM>, where a confirmation signal indicating that the locking tongue has been inserted into one of the entry slots is generated. In an example implementation, the confirmation signal may be an interlock signal sent to an external or internal control system that controls the position of the locking switch's locking bolt, such that the locking bolt is engaged only if the confirmation signal is received. The first, second, and third RFID coils can be electrically connected together in series, and the determinations as to whether the RFID tag has been detected by any of the three RFID coils can be made by detection circuitry based on measured modulations induced on a current through the coils as a result of disturbances to the coils' electromagnetic fields by the RFID tag.

<FIG> is an example methodology <NUM> for validating correct operation of an inductive sensor used to detect the position of the locking bolt of an industrial locking switch. Initially, at <NUM>, a position of the locking bolt is detected based on measurement of a frequency shift of the inductive sensor's current, where this frequency shift is caused by presence of the locking bolt within a magnetic field of the inductive sensor. In an example implementation, the inductive sensor may comprise an LC tank circuit having an inductive coil positioned such that the locking bolt enters the inductive coil's magnetic field when advanced to the locked position.

At <NUM>, a determination is made as to whether a diagnostic test of the inductive sensor is initiated. If the diagnostic test is not initiated (NO at step <NUM>), the methodology returns to step <NUM> and the locking switch continues to operate normally, with the inductive sensor detecting when the locking bolt is in the advanced (locked) position during normal operation. If the diagnostic test is initiated (YES at step <NUM>), the methodology proceeds to step <NUM>, where a diagnostic switch is enabled that electrically connects a diagnostic capacitor to the inductive sensor. Electrically connecting the diagnostic capacitor changes the capacitance of the inductive sensor in a manner that replicates the frequency shift induced by the presence of the locking bolt during normal operation.

At <NUM>, a determination is made as to whether a frequency shift similar to that caused by presence of the locking bolt in its locked position is detected. If such a frequency shift is detected (YES at step <NUM>), operation of the inductive sensor is validated and the methodology returns to step <NUM>. If the frequency shift is not detected (NO at step <NUM>), the methodology proceeds to step <NUM>, where a determination is made as to whether a defined time duration has elapsed since enabling the diagnostic switch at step <NUM>. If the defined duration has not elapsed (NO at step <NUM>), the methodology returns to step <NUM> and the inductive sensor continues to be monitored for the expected frequency shift. Steps <NUM> and <NUM> repeat until either the frequency shift is detected at step <NUM> (thereby validating operation of the inductive sensor) or the defined time duration elapses at step <NUM>. If the expected frequency shift is not detected before the defined time duration has elapsed (YES at step <NUM>), the methodology proceeds to step <NUM>, where an error signal is generated indicating that operation of the inductive sensor cannot be validated.

Embodiments, systems, and components described herein, as well as industrial control systems and industrial automation environments in which various aspects set forth in the subject specification can be carried out, can include computer or network components such as servers, clients, programmable logic controllers (PLCs), automation controllers, communications modules, mobile computers, wireless components, control components and so forth which are capable of interacting across a network. Computers and servers include one or more processors-electronic integrated circuits that perform logic operations employing electric signals-configured to execute instructions stored in media such as random access memory (RAM), read only memory (ROM), a hard drives, as well as removable memory devices, which can include memory sticks, memory cards, flash drives, external hard drives, and so on.

Similarly, the term PLC or automation controller as used herein can include functionality that can be shared across multiple components, systems, and/or networks. As an example, one or more PLCs or automation controllers can communicate and cooperate with various network devices across the network. This can include substantially any type of control, communications module, computer, Input/Output (I/O) device, sensor, actuator, instrumentation, and human machine interface (HMI) that communicate via the network, which includes control, automation, and/or public networks. The PLC or automation controller can also communicate to and control various other devices such as standard or safety-rated I/O modules including analog, digital, programmed/intelligent I/O modules, other programmable controllers, communications modules, sensors, actuators, output devices, and the like.

The network can include public networks such as the internet, intranets, and automation networks such as Common Industrial Protocol (CIP) networks including DeviceNet, ControlNet, and Ethernet/IP. Other networks include Ethernet, DH/DH+, Remote I/O, Fieldbus, Modbus, Profibus, CAN, wireless networks, serial protocols, near field communication (NFC), Bluetooth, and so forth. In addition, the network devices can include various possibilities (hardware and/or software components). These include components such as switches with virtual local area network (VLAN) capability, LANs, WANs, proxies, gateways, routers, firewalls, virtual private network (VPN) devices, servers, clients, computers, configuration tools, monitoring tools, and/or other devices.

In order to provide a context for the various aspects of the disclosed subject matter, <FIG> and <FIG> as well as the following discussion are intended to provide a brief, general description of a suitable environment in which the various aspects of the disclosed subject matter may be implemented.

With reference to <FIG>, an example environment <NUM> for implementing various aspects of the aforementioned subject matter includes a computer <NUM>. The computer <NUM> includes a processing unit <NUM>, a system memory <NUM>, and a system bus <NUM>. The system bus <NUM> couples system components including, but not limited to, the system memory <NUM> to the processing unit <NUM>. The processing unit <NUM> can be any of various available processors. Multi-core microprocessors and other multiprocessor architectures also can be employed as the processing unit <NUM>.

The system bus <NUM> can be any of several types of bus structure(s) including the memory bus or memory controller, a peripheral bus or external bus, and/or a local bus using any variety of available bus architectures including, but not limited to, <NUM>-bit bus, Industrial Standard Architecture (ISA), Micro-Channel Architecture (MSA), Extended ISA (EISA), Intelligent Drive Electronics (IDE), VESA Local Bus (VLB), Peripheral Component Interconnect (PCI), Universal Serial Bus (USB). Advanced Graphics Port (AGP). Personal Computer Memory Card International Association bus (PCMCIA), and Small Computer Systems Interface (SCSI).

The system memory <NUM> includes volatile memory <NUM> and nonvolatile memory <NUM>. The basic input/output system (BIOS), containing the basic routines to transfer information between elements within the computer <NUM>, such as during start-up, is stored in nonvolatile memory <NUM>. By way of illustration, and not limitation, nonvolatile memory <NUM> can include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable PROM (EEPROM), or flash memory. Volatile memory <NUM> includes random access memory (RAM), which acts as external cache memory. By way of illustration and not limitation, RAM is available in many forms such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM).

Computer <NUM> also includes removable/non-removable, volatile/nonvolatile computer storage media. <FIG> illustrates, for example a disk storage <NUM>. Disk storage <NUM> includes, but is not limited to, devices like a magnetic disk drive, floppy disk drive, tape drive, Jaz drive, Zip drive, LS-<NUM> drive, flash memory card, or memory stick. In addition, disk storage <NUM> can include storage media separately or in combination with other storage media including, but not limited to, an optical disk drive such as a compact disk ROM device (CD-ROM), CD recordable drive (CD-R Drive), CD rewritable drive (CD-RW Drive) or a digital versatile disk ROM drive (DVD-ROM). To facilitate connection of the disk storage <NUM> to the system bus <NUM>, a removable or non-removable interface is typically used such as interface <NUM>.

It is to be appreciated that <FIG> describes software that acts as an intermediary between users and the basic computer resources described in suitable operating environment <NUM>. Such software includes an operating system <NUM>. Operating system <NUM>, which can be stored on disk storage <NUM>, acts to control and allocate resources of the computer <NUM>. System applications <NUM> take advantage of the management of resources by operating system <NUM> through program modules <NUM> and program data <NUM> stored either in system memory <NUM> or on disk storage <NUM>. It is to be appreciated that one or more embodiments of the subject disclosure can be implemented with various operating systems or combinations of operating systems.

A user enters commands or information into the computer <NUM> through input device(s) <NUM>. Input devices <NUM> include, but are not limited to, a pointing device such as a mouse, trackball, stylus, touch pad, keyboard, microphone, joystick, game pad, satellite dish, scanner, TV tuner card, digital camera, digital video camera, web camera, and the like. These and other input devices connect to the processing unit <NUM> through the system bus <NUM> via interface port(s) <NUM>. Interface port(s) <NUM> include, for example, a serial port, a parallel port, a game port, and a universal serial bus (USB). Output device(s) <NUM> use some of the same type of ports as input device(s) <NUM>. Thus, for example, a USB port may be used to provide input to computer <NUM>, and to output information from computer <NUM> to an output device <NUM>. Output adapters <NUM> are provided to illustrate that there are some output devices <NUM> like monitors, speakers, and printers, among other output devices <NUM>, which require special adapters. The output adapters <NUM> include, by way of illustration and not limitation, video and sound cards that provide a means of connection between the output device <NUM> and the system bus <NUM>. It should be noted that other devices and/or systems of devices provide both input and output capabilities such as remote computer(s) <NUM>.

Computer <NUM> can operate in a networked environment using logical connections to one or more remote computers, such as remote computer(s) <NUM>. The remote computer(s) <NUM> can be a personal computer, a server, a router, a network PC, a workstation, a microprocessor based appliance, a peer device or other common network node and the like, and typically includes many or all of the elements described relative to computer <NUM>. For purposes of brevity, only a memory storage device <NUM> is illustrated with remote computer(s) <NUM>. Remote computer(s) <NUM> is logically connected to computer <NUM> through a network interface <NUM> and then physically connected via communication connection <NUM>. Network interface <NUM> encompasses communication networks such as local-area networks (LAN) and wide-area networks (WAN). LAN technologies include Fiber Distributed Data Interface (FDDI), Copper Distributed Data Interface (CDDI), Ethernet/IEEE <NUM>, Token Ring/IEEE <NUM> and the like. WAN technologies include, but are not limited to, point-to-point links, circuit switching networks like Integrated Services Digital Networks (ISDN) and variations thereon, packet switching networks, and Digital Subscriber Lines (DSL). Network interface <NUM> can also encompass near field communication (NFC) or Bluetooth communication.

Communication connection(s) <NUM> refers to the hardware/software employed to connect the network interface <NUM> to the system bus <NUM>. While communication connection <NUM> is shown for illustrative clarity inside computer <NUM>, it can also be external to computer <NUM>. The hardware/software necessary for connection to the network interface <NUM> includes, for exemplary purposes only, internal and external technologies such as, modems including regular telephone grade modems, cable modems and DSL modems, ISDN adapters, and Ethernet cards.

<FIG> is a schematic block diagram of a sample computing environment <NUM> with which the disclosed subject matter can interact. The sample computing environment <NUM> includes one or more client(s) <NUM>. The client(s) <NUM> can be hardware and/or software (e.g., threads, processes, computing devices). The sample computing environment <NUM> also includes one or more server(s) <NUM>. The server(s) <NUM> can also be hardware and/or software (e.g., threads, processes, computing devices). The servers <NUM> can house threads to perform transformations by employing one or more embodiments as described herein, for example. One possible communication between a client <NUM> and servers <NUM> can be in the form of a data packet adapted to be transmitted between two or more computer processes. The sample computing environment <NUM> includes a communication framework <NUM> that can be employed to facilitate communications between the client(s) <NUM> and the server(s) <NUM>. The client(s) <NUM> are operably connected to one or more client data store(s) <NUM> that can be employed to store information local to the client(s) <NUM>. Similarly, the server(s) <NUM> are operably connected to one or more server data store(s) <NUM> that can be employed to store information local to the servers <NUM>.

What has been described above includes examples of the subject innovation. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the disclosed subject matter, but one of ordinary skill in the art may recognize that many further combinations and permutations of the subject innovation are possible. Accordingly, the disclosed subject matter is intended to embrace all such alterations, modifications, and variations that fall within the scope of the appended claims.

In particular and in regard to the various functions performed by the above described components, devices, circuits, systems and the like, the terms (including a reference to a "means") used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., a functional equivalent), even though not structurally equivalent to the disclosed structure, which performs the function in the herein illustrated exemplary aspects of the disclosed subject matter. In this regard, it will also be recognized that the disclosed subject matter includes a system as well as a computer-readable medium having computer-executable instructions for performing the acts and/or events of the various methods of the disclosed subject matter.

In addition, while a particular feature of the disclosed subject matter may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms "includes," and "including" and variants thereof are used in either the detailed description or the claims, these terms are intended to be inclusive in a manner similar to the term "comprising.

In this application, the word "exemplary" is used to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the word exemplary is intended to present concepts in a concrete fashion.

Claim 1:
A locking switch (<NUM>), comprising:
a housing (<NUM>) comprising two or more entry slots (<NUM>), wherein each of the two or more entry slots is configured to receive a locking tongue (<NUM>);
a solenoid-driven locking bolt inside the housing and configured to engage with an engagement hole (<NUM>) formed in the locking tongue in response to advancing to a locked position while the locking tongue is inserted into any one of the two or more entry slots;
two or more radio frequency identifier, RFID, coils (<NUM>) mounted inside the housing and positioned above the two or more entry slots, respectively, wherein the two or more RFID coils are electrically connected in series, and wherein each of the two or more RFID coils is configured to, in response to insertion of the locking tongue into a corresponding one of the two or more entry slots, detect a presence of an RFID tag (<NUM>) mounted on the locking tongue; and
a bobbin (<NUM>) mounted inside the housing,
wherein
the bobbin comprises a first surface that is slanted relative to a second surface opposite the first surface and the bobbin comprises an opening (<NUM>) in a center of the bobbin configured to receive the locking bolt when the locking bolt advances to a locked position,
the two or more RFID coils are mounted to the first surface, and
the slanted surface orients the two or more RFID coils to direct an axis of each of the two or more RFID coils outward from the center of the bobbin.