Test button operation tracker

Abstract

A circuit breaking device comprising a test button is provided. The test button 110 comprises a first member 111 that is configured to rotate around a longitudinal axis when the test button 110 is actuated such that the rotational position of the first member before actuation of the test button is different to the rotational position of the first member after actuation of the test button. A user may inspect the rotational position of the first member of the test button to determine whether the test button has been actuated in accordance with a predefined schedule.

Description

[0001] Test Button Operation Tracker

[0002] Field

[0003] The disclosure relates to a test button operation tracker. In particular, the disclosure relates to a test button for a circuit breaker that allows a user to determine information relating the previous operation of the test button via visual inspection.

[0004] Background

[0005] Circuit breaking devices are required to perform reliable disconnection of a current path under one or more fault conditions. It is known to include test buttons in circuit breaking devices to allow users to confirm that a circuit breaking device is functioning correctly. A test button may simulate a fault condition in the circuit breaker and thereby confirm that the circuit breaking device is capable of responding correctly to the fault condition. For example, a test button may simulate a leakage current in an ROD (Residual Current Device), RCCB (Residual Current Circuit Breaker) or RCBO (Residual Current Circuit Breaker with Overcurrent Protection) to ensure a current path is interrupted when a leakage current is present.

[0006] Testing of a circuit breaking device may be required to be performed at prescribed regular intervals. The requirements for testing may be defined, for example, by the manufacturer of the circuit breaking device, a safety standards organization, government legislation, or the internal policy of a company or organization. IEC 62350 standard recommends that RCDs are tested using a test button once every six months for residential or similar application. Manufacturers may specify more stringent testing requirements based on the device design, such as requiring monthly testing. Ensuring that testing is performed with the required regularity requires accurate recording of performed test events, scheduling of future test events, and communication of the test history with members of a team responsible for testing of the safety equipment. Such procedures are burdensome and can lead to safety failures when performed unreliably. Furthermore, existing testing procedures do not provide any means for verifying recorded information in relation to test.

[0007] There is a need for a circuit breaking device having the capability of improved features for determining past test operations of the test device.

[0008] Summary of Invention

[0009] One aspect of the disclosure provides a circuit breaking device comprising a test button. The test button comprises a first member that is configured to rotate around alongitudinal axis when the test button is actuated such that the rotational position of the first member before actuation of the test button is different to the rotational position of the first member after actuation of the test button. A user may inspect the rotational position of the first member of the test button to determine whether the test button has been actuated in accordance with a predefined schedule. For example, a user may compare the actual rotational position of the first member with the expected rotational position of the first member that would result from actuation of the test button according to the predefined schedule. A discrepancy between the actual rotation position and the expected rotational position may be used as an indication that the schedule has not been followed correctly or as a prompt for performing an operation with the test button to bring the rotational position of the first member into correspondence with the expected position.

[0010] In some examples, the test button is configured to be actuated by pressing the test button in a first direction parallel with the longitudinal axis. In these examples, actuation of the test button can be performed in the same way regardless of the rotational position of the first member. This provides a simple mechanism for linking the position of the first member of the test button to a physical operation of the test button.

[0011] In some examples, pressing the test button causes the first member to rotate about its longitudinal axis while moving linearly along the first direction.

[0012] In some examples, the position of the first member after actuation of the test button corresponds to the position of the first member before actuation of the test button rotated around the longitudinal axis.

[0013] In some examples, the first member rotates through an angle of less than 360° when the test button is actuated and, preferably, wherein the first member rotates through an angle of 360° / N, where N is an integer. The cycle of N positions of the first member can be repeated indefinitely without the device needing to be reset.

[0014] In some examples, actuation of the test button comprises a first linear motion in which the first member moves along a first direction from a first position to a second position, and a second linear motion in which the first member returns to first position from the second position.

[0015] In some examples, the circuit breaking device, further comprises a fixed pin, wherein the first member comprises an outer surface comprising a groove arranged to receivethe pin such that the pin guides the first member to undergo a rotation when the first member moves linearly along the first direction.

[0016] In some examples, the first direction is parallel to the longitudinal axis of the first member.

[0017] In some examples, the test button further comprises a first resilient member that biases the first member in a linear direction towards the first position. The first resilient member causes the first member to return to the same position at the after actuation of the test button as before actuation of the test button.

[0018] In some examples, the first member comprises a first surface having at least two indicia thereon, wherein the test button further comprises a second member surrounding at least part of the first surface of the first member, the second member comprising a window that allows one of the at least two indicia to be seen depending on the rotational position of the first member. The indicia visible on the first surface of the first member can be used to indicate the rotational position of the first member to a user.

[0019] In some examples, when the test button is actuated, the second member linearly comoves with the first member without rotating, such that the first member rotates with respect to the second member.

[0020] In some examples, the second member covers at least one of the at least two indicia depending on the rotational position of the first member.

[0021] In some examples, the at least two indicia indicate different time periods or different numbers. The time periods or numbers can be compared with the time periods or numbers expected when following a predefined schedule to determine whether the schedule operation of the test button is in accordance with the schedule.

[0022] In some examples, the at least two indicia indicate halves of the year, quarters of the year, the names of months, or days of the week.

[0023] In some examples, actuation of the test button causes a leakage current to introduced between a neutral line and a test line of the circuit breaker.

[0024] In some examples, the test button comprises a second resilient member that biases the first member in a first rotational direction during at least part of the motion of thefirst member when the test button is actuated. The second resilient member ensures that rotation of the first member is always in the same direction.

[0025] In some examples, the second resilient member engages a section of a side surface of the first member having a substantially polygonal cross section.

[0026] Brief Description of the Figures

[0027] The disclosure is described with reference to the following figures:

[0028] Fig. 1 provides a schematic illustration of a circuit breaking device in accordance with examples of the disclosure;

[0029] Fig. 2a and 2b illustrate a test button in accordance with examples of the disclosure; Fig. 3 illustrates a first member of a test button in accordance with an example of the disclosure;

[0030] Fig. 4 illustrates a resilient member in accordance with an example of the disclosure; Fig. 5a illustrates a sectional view of a circuit breaking device without showing the test button;

[0031] Fig. 5b illustrates a sectional view of a circuit breaking device including the test button;

[0032] Fig. 6 illustrates a sectional view of part of a circuit breaking device in which the test button is in a state that occurs before and after actuation of the test button;

[0033] Fig. 7 illustrates a sectional view of part of a circuit breaking device in which the test button is in a state that occurs during actuation of the test button;

[0034] Figs. 8a and 8b illustrate a plan view of a circuit breaking device before and after actuation of the test button.

[0035] Detailed Description

[0036] Disclosed herein is a circuit breaking device comprising a test button. The circuit breaking device may be a R.CCB, an RCBO or any other type of circuit breaking device configured to interrupt a current path under a fault condition or in response to a user input. The test button comprises a first member that rotates when the test button is actuated, resulting in the rotational position of the first member being different before and after actuation of the test button. A user may infer information relating to past use of the test button based on the rotational position of the first member. A user may inspect the rotational position of the first member of the test button to determine whether the test button has been actuated in accordance with a predefined schedule. For example, a user may compare the actual rotational position of the first member with the expected rotational position of the first member that would result from actuation of the test button in accordance with the predefined schedule. In some examples, a second member covers a portion of the first member. A window in thesecond member reveals a portion of the first member depending on the rotational position of the first member. Markings (or indicia) on a surface of the first member visible through the window can be used to convey information to the user regarding the past operational states of the circuit breaking device.

[0037] The terms upwards, downwards, top and bottom are used in the description to describe different relative positions of elements in examples of the illustrated embodiments. The skilled person will understand that these terms do not refer to absolute positions of these element in reality, and that the terms do not imply that a specific orientation of the device is necessary for the technical effect of the disclosure. The term "position" is used to refers to the displacement of the element without consideration of its orientation. Therefore, an element can return to the "same position" with a different orientation (or "rotational position"), as described in more detail below.

[0038] Fig. 1 provides a schematic block diagram representing a circuit breaking device 100 according to an example of the present disclosure. The circuit breaking device 100 described here in detail is an RCD / RCCB / RCBO that causes electric contacts of an electromechanical switch 101 in a circuit path to be opened in response to detecting a leakage current between the phase line 102 and the neutral line 103 of the circuit breaking device 100 (that is, detecting a difference between the magnitude of the current in the phase line 102 and the neutral line 103). The skilled person will understand that the operational principles of the disclosure below can be applied to other types of circuit breaking devices. For example, the contacts of the switching device may be opened based on the detection of another fault condition, such as an overcurrent condition, based on a remote operation signal from a user, or based on one or more of several different detected fault conditions and control signals and mechanisms. While the detailed disclosure describes an electromechanical switch 101 that interrupts a current path by the opening of electric contacts, the skilled person will understand that the current path may be interrupted using one or more solid state switches, a hybrid switching arrangement, or another type of switching arrangement.

[0039] The circuit breaking device 100 comprises a phase line 102 and a neutral line 103. The electromechanical switch 101 is disposed in the path of one or both of the phase line 102 and neutral line 103. A trip unit 104 is connected to electromechanical switch 101. The trip unit 104 is configured to open electrical contacts of the electromechanical switch 101 on detection of one or more fault conditions. In this example, the trip unit 104 is configured to open contacts of the electromechanical switch 104 on detection ofa residual current condition and / or and an overcurrent condition. The circuit breaking device 100 comprises a residual current detector 105 configured to detect a leakage current between the neutral line 103 and the phase line 102 of the circuit breaking device 100. The residual current detector 105 may comprise a coil disposed around the phase line 102 and the neutral line 103 such that a difference in the current between the phase line 102 and neutral line 103 causes a voltage to be induced in the coil. The residual current detector 105 is configured to send a trip signal to the trip unit 104 causing the electromechanical switch 101 to be opened on detection of a leakage current. The circuit breaking device 100 comprises a test button 110 configured to simulate a leakage current between the phase line 102 and the neutral line 103 when the circuit breaking device is actuated. In some examples, actuation of the test button 110 may simulate a leakage current by causing an electrical connection to be made between the phase line 102 and ground, between the phase line 102 and a voltage source, between the neutral line 103 and a voltage source, or between the phase line 102 and / or the neutral line 103 and another element.

[0040] In other examples, the test button 110 may simulate another fault condition, such as an overcurrent condition, or may provide a control signal to the trip unit 105.

[0041] Figures 2a, 2b and 3 illustrate components of the test button 110. The test button 110 comprises a first member 111, a second member 112 and a guiding feature 113. The first member 111 has an elongate form with a circular end portion 115a. The first member 111 may be substantially cylindrical or have substantially cylindrical sections. The second member 112 covers at least part of the end portion 115a of the first member 111. The second member 112 comprises a window 119 that reveals a portion of the end portion 115a of the first member 111. The first member 111 comprises a plurality of indicia (or "markings") 116 thereon that are disposed such that one of the indicia 116 is visible through the window 119 of the second member 112 depending on the rotational position of the first member 111 with respect to the second member 112.

[0042] In other examples, the indicia 116 may be arranged on a different portion of the first member 111. For example, the first member may comprise indicia 116 arranged on a side surface 115b of the first member 111, and the window 119 of the second member 112 may be arranged to reveal a portion of the side surface 115b depending on the rotational position of the first member 111.In some examples, the second member 112 may be omitted from the test button 110. In these examples, a user may determine information regarding the past operation of the test button 110 based on the position of the first member 111 without the use of the second member 112. For example, a user may identify a marking on the first member 111 that is oriented upright or that is aligned with a feature on a circuit breaker housing 150 to determine information regarding previous operations of the test button 110. In other examples, a housing 150 of the circuit breaker may comprise a window that reveals a marking on part of the first member 111 depending on the rotational position of the first member 111.

[0043] Actuation of the test button 110 is performed by a user pressing the second member 112 of the test button 110, which extends above an upper surface 150a of a housing of the circuit breaking device when not being pressed (as shown in Fig. 5b). When the second member 112 is pressed, the first member 111 and second member 112 both move linearly along a first direction DI within a recess in a housing 150 of the circuit breaking device 100. The test button 110 comprises a guiding feature 113 that engages an inner surface of the recess of the housing to guide the second member along a linear path. The guiding feature 113 may be coupled to the second member 112 or may be formed integrally with the second member 112. The guiding feature 113 is shaped to prevent rotation of the second member 112 as it moves along the linear path. The first member 111 is shaped to be received within a hollow portion of the second member 112 such that motion of the second member 112 along the linear path causes the first member 111 to move along the linear path. The first member 111 is able to rotate within the hollow portion of the second member 112. Preferably, the first member 111 rotates around a longitudinal axis of the first member 111 that is substantially parallel to the first direction DI. The first member 111 and the second member 112 are coupled such that they comove linearly; that the first member 111 and the second member 112 remain at the same position with respect to each other in terms of linear motion while their orientation may rotate with respect to each other. At the bottom of the linear motion, the test button 110 activates a residual current simulating mechanism to cause a leakage current to be introduced between the phase line 102 and the neutral line 103. In some examples, actuation of the test button 110 may cause a conductive element connected to neutral or ground to contact the phase line 102 at the fully compressed position. A first resilient member 141, such as a torsional spring, a coil spring, a cantilever, or a leaf spring, biases the first member 111 away from the bottom of the linear motion towards its original position. When the actuation force applied by the user is removed, both the first member 111 and the second member 112 move linearly back to the initial position along the first directionDI. The position of the first member 111 at the beginning and end of the actuation cycle is referred to here as the first position. The position of the first member 111 at the bottom point of its linear motion is referred to as the second position.

[0044] While the first member 111 and the second member 112 perform a corresponding linear motion during actuation of the test button, the first member 111 undergoes a rotational motion with respect to the second member 112. Preferably, the first member 111 rotates while the second member 112 remains stationary. This is advantageous as it allows the second member 112 to be pressed by the finger of a user without generation of friction between the user's finger and the second member 112.

[0045] Rotation of the first member 111 is guided by a fixed pin 114 (or protrusion) that moves along a groove 117 (or channel) defined in the side surface 115b of the first member 111. The fixed pin 114 may extend from the housing 150 of the circuit breaking device 100, as shown in Fig. 5a. The groove 117 in the side surface 115a of the first member 111 is disposed in the side surface of a substantially cylindrical section 120 of the first member 111. The groove 117 comprises a first segment 117a configured to cause the first member 111 to rotate in a first rotational direction when the first member moves linearly downwards (i.e. from the first position to the second position) and a second segment 117b configured to cause the first member 111 to continue to rotate in the first direction when the first member 111 moves upwards (i.e. from the second position to the first position). In the illustrated example, the groove 117 comprises two first segments 117a and two second segments 117b. Each time the test button 110 is actuated, the first member rotates 111 in the first rotational direction through an angle of 180° with respect to the second member (i.e.

[0046] 90° during the downward motion and 90° during the upward motion). As such, the first member 111 returns to its original rotational position when actuated twice. In other examples, the test button 110 may be configured such that the first member 111 rotates through an angle of 360 ° / N during each actuation of the test button, where N is an integer greater than 1. As such, the first member returns to its original rotational position with respect to the second member 112 after the test button 110 has been actuated N times. The sequence of positions of the first member 111 can be repeated indefinitely with subsequent actuations of the test button 110.

[0047] In examples where the second member 112 is omitted, the above-described rotational angles can be measured between the first member 111 and the housing 150. Though the first and second segments 117a, 117b are substantially symmetrical in theillustrated examples, the angle through which the first member rotates may be different during the upward motion and the downward motion. In some examples, the first member 111 may only rotate during the downward motion.

[0048] A second resilient member 140, shown in Fig. 4, engages the first member 111 and biases the first member 111 in the first rotational direction 111 during at least part of the motion of the first member 111 when the test button 110 is actuated. The second resilient member 140 is formed of a flexible material and may be embodied as a torsional spring, a cantilever, a leaf spring, or another suitable element. The second resilient member 140 ensures that the first member 111 continues to rotate in the first rotational direction when the linear motion of the first member changes direction (i.e. at the first position or at the second position) rather than counter-rotating. The second resilient element 140 is arranged to engage an engagement section 118 of the side surface 115b of the first member 111 having a substantially square cross section. The second resilient member 140 is maximally loaded as the first member 111 reaches the first position and the second position and is partially unloaded at intermediate position. The second resilient member 140 may partially oppose rotation of the first member 111 at intermediate positions, provided that the rotational torque produced by the user's actuating force or the returning force of the first resilient member 141 is sufficient to overcome the opposing force. The second resilient member 140 may be mounted to the second member 112 and generate a rotational force between the first member 111 and the second member 112. In general, when the test button 110 is configured such that first member rotates through an angle of 360° / N each time the test button is actuated, the engagement section 118 has a cross section of a 2N-sided polygon.

[0049] The rotational motion of the first member 111 with respect to the second member 112 causes a different portion of the first surface 115a of the first member to be aligned with the window 119 of the second member before and after actuation of the test button. The markings that are visible at any one time provide an indication to the user of the previous actuation history of the test button 110. In particular, the markings 116 visible to a user through the window 119 of the second member are different before and after actuation of the test button 110. The markings 116 can be used to provide an indication of whether a test needs to be performed or whether a test is due. For example, when markings on the test button 110 indicate a series of time periods, a user may understand that the test button 110 is required to be actuated to cause the visible markings on the test button 110 to match the current time-period.Fig. 6 provides a cross-sectional view of the circuit breaking device in a state in which the test button 110 is not being actuated (i.e. the test button is at rest). A portion of the test button 110 protrudes from the housing 150 of the circuit breaking device by extending above an upper surface 150a of the housing 150. A user may actuate the test button by pressing the protruding portion of the test button 110. In the illustrated example, the protruding portion may comprise part of the first member 111 and part of the second member 112. In this example, the first member is in the first position.

[0050] Fig. 7 provides a cross-sectional view of the circuit breaking device in a state in which the test button 110 is fully actuated (i.e. the test button has been compressed to its maximum extent). In this state, the first member is in the second position. In the second position, the first member is linearly displaced in the first direction DI from the first position. The first member in Fig. 7 has also undergone a rotation around a longitudinal axis 106 with respect to the rotational position of Fig. 6.

[0051] When the test button 110 is actuated, the first member 111 of the test button moves along a linear path from the first position, shown in Fig. 6, to the second position shown in Fig. 7, and returns along the same linear path to the first position of Fig. 6. At the same time, the first member 111 rotates around its longitudinal axis 106. As such, the position of the first member 111 after actuation of the test button 110 corresponds to the position of the first member 111 prior to actuation of the test button 110 with a rotation around the longitudinal axis 106. That is, after actuation of the test button 110, the first member 111 ends up in the same position along the linear path as it started but at a different rotational orientation. In general, the state of the test button 110 after actuation of the test button 110 may be identical to the state of the test button 110 prior to actuation of the test button 110 other than the rotation of the first member 111.

[0052] Figs. 8a and 8b show a view of an example of the circuit breaking device before and after actuation of the test button 110 respectively as seen by a user inspecting the circuit breaking device. In Fig. 8a, a first marking 116a is visible through the window portion of the second member 112. In Fig. 8b, a second marking 116b is visible through the window portion of the second member 112 due to the device having been activated.

[0053] In the illustrated example, the first surface of the first member includes two indicia: "Hl" and "H2". In this example, the test button can be used to indicate the half of the year that the previous test is performed. Where activation of the test button isrequired twice a year, one test can be performed in the first half of the year and another test can be performed in the second half of the year. A user inspecting the test button in the first half of the year will know that a test is required if the visible indicium on the test button indicates "H2". After actuating the test button to perform a test, the rotation of the first member will cause "Hl" to become visible. Users inspecting the test button at a later date will know that a further test is not due until the second half of the year. During the second half of the year, actuation of the test button will cause the indicium "H2" to return to the visible position.

[0054] Other indicia may be used depending on the frequency of testing and the scheme used to interpret the indicia. In an example where monthly testing in required, the first member may rotate through an angle of 30°each time the test button is actuated. In this example, the indicia may indicate each month of the year. In other examples, the indicia may indicate a time-period (such as a half of the year, a quarter of the year, a month, a day of the week etc.), a number, or any other information that may assist a user in determining whether a test is due.

[0055] In an example, the indicia 116 provide four indications representing different quarters of the year, and the first member rotates through 90° each time the test button 110 is actuated.

[0056] In another example, the indicia 116 provide seven indications representing different days of the week, and the first member rotates through about 51° each time the test button 110 is actuated.

[0057] In an example, the indicia 116 provide N numbered indications, and the first member rotates through 360° / N each time the test button 110 is actuated. The numbered indications may provide a counter of the number of tests that have been performed.

[0058] The above-described device provides a simple and robust mechanical arrangement to allow users to track the previous usage of a test button in a circuit breaking device 110. The position of the first member 111 can be used to provide an indication that a test is due or that a test for a specified time-period has been performed. The position of the first member 111 can also provide physical evidence that a test has been performed in order to cross-refence administrative records.List of reference numerals

[0059] 100 Circuit breaking device

[0060] 101 Electromechanical switch

[0061] 102 Phase line

[0062] 103 Neutral line

[0063] 104 Trip unit

[0064] 105 Residual current detector

[0065] 110 Test button

[0066] 111 First member

[0067] 112 Second member

[0068] 113 Guiding feature

[0069] 119 Window

[0070] 114 Pin

[0071] 115a End portion of the first member 115b Side surface of the first member 116a First indicia

[0072] 116b Second indicia

[0073] 117 Groove

[0074] 117a First segment of groove

[0075] 117b Second segment of groove

[0076] 118 Engagement section

[0077] 140 Second resilient member

[0078] 150 Housing

[0079] 150a Upper surface of housing

[0080] 106 Longitudinal axis of first member DI First direction

Claims

Claims1. A circuit breaking device comprising a test button, wherein the test button (110) comprises a first member (111) that is configured to rotate around a longitudinal axis (106) when the test button (110) is actuated such that the rotational position of the first member (111) before actuation of the test button (110) is different to the rotational position of the first member (111) after actuation of the test button.

2. The circuit breaking device of claim 1, wherein the test button (110) is configured to be actuated by pressing the test button in a first direction parallel with the longitudinal axis (106).

3. The circuit breaking device of claim 2, wherein pressing the test button (110) causes the first member (111) to rotate about its longitudinal axis while moving linearly along the first direction (DI).

4. The circuit breaking device of any of claims 1 to 3, wherein the position of the first member (111) after actuation of the test button corresponds to the position of the first member (111) before actuation of the test button rotated around the longitudinal axis (106).

5. The circuit breaking device of any preceding claim, wherein the first member (111) rotates through an angle of less than 360° when the test button (110) is actuated and, preferably, wherein the first member rotates through an angle of 360° / N, where N is an integer.

6. The circuit breaking device of any preceding claim, wherein actuation of the test button (110) comprises a first linear motion in which the first member (111) moves along a first direction (DI) from a first position to a second position, and a second linear motion in which the first member (111) returns to first position from the second position.

7. The circuit breaking device of claim 6, further comprising a fixed pin (114), wherein the first member (111) comprises an outer surface comprising a groove (117) arranged to receive the pin such that the pin guides the first member to undergo a rotation when the first member moves linearly along the first direction, wherein, preferably, the first direction is parallel to the longitudinal axis of the first member.

8. The circuit breaking device of claim 7, wherein the test button further comprises a first resilient member that biases the first member in a linear direction towards the first position.

9. The circuit breaking device of any preceding claim, wherein the first member comprises a first surface (115a) having at least two indicia (116) thereon, wherein the test button (110) further comprises a second member (112) surrounding at least part of the first surface of the first member (111), the second member (112) comprising a window (119) that allows one of the at least two indicia to be seen depending on the rotational position of the first member (111).

10. The circuit breaking device of claim 9, wherein the second member (112) covers at least one of the at least two indicia depending on the rotational position of the first member (111).

11. The circuit breaking device of claim 9 or claim 10, wherein when the test button (110) is actuated, the second member (112) linearly comoves with the first member (111) without rotating, such that the first member (111) rotates with respect to the second member (112).

12. The circuit breaking device of any of claims 9-11, wherein each of the at least two indicia (116) respectively indicate different time periods or different numbers, and preferably, wherein the at least two indicia (116) indicate halves of the year, quarters of the year, the names of months, or days of the week.

13. The circuit breaking device of any preceding claim, wherein actuation of the test button (110) causes a leakage current to introduced between a neutral line (103) and a phase line (102) of the circuit breaking device.

14. The circuit breaking device of any preceding claim, wherein the test button (110) comprises a second resilient member (140) that biases the first member (111) in a first rotational direction during at least part of the motion of the first member (111) when the test button is actuated.

15. The circuit breaking device of claim 14, wherein the second resilient member (140) engages a section of a side surface (118) of the first member (111) having a substantially polygonal cross section.

Images