Clamp sensors and measuring devices

Abstract

To provide a clamp sensor that allows operation for bringing into lock state / unlock states to be performed reliably and easily, as well as, allows for reliably and easily recognizing which of the lock state and the unlock state the clamp sensor has been brought in, while reducing manufacturing costs.SOLUTION: A clamp sensor includes a rotational movement restricting member 23 with an end part 23a pivotably supported on an operational arm 21. The rotational movement restricting member is configured to: in a "first state" after rotated relatively to the operational arm 21 so as to prevent the end part 23b from contacting an operational arm 22, permit the operational arm 21 to rotate relatively to the operational arm 22 in a direction that brings clamp arms 11, 12 into an open state from a closed state; or, in a "second state" after rotated relatively to the operational arm 21 so as to bring the end part 23b into contact with the operational arm 22, restrict the operational arm 21 from rotating relatively to the operational arm 22 in a direction that brings the clamp arms 11, 12 into the open state from the closed sate.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a clamp sensor that has a pair of clamp arms that form a ring-shaped sensor portion in a closed state with their tips close together, and is configured so that both clamp arms can be rotated to move the tips closer and farther apart, and to a measuring device that is configured with such a clamp sensor. [Background technology]

[0002] As this type of clamp sensor, the applicant has disclosed a clamp sensor having a pair of clamp portions that can be opened and closed in the following patent document.

[0003] In the clamp sensor disclosed by the applicant, the base ends of both clamp parts are rotatably supported by a pair of support shafts in the outer case part (main body part), and both clamp parts are constantly biased by a coil spring so that the tip ends are in contact with each other (closed state). The clamp sensor disclosed by the applicant also includes a pair of operating levers for moving the tip ends of both clamp parts to a state in which they are separated from each other (open state). In this case, both operating levers in this clamp sensor are disposed on both the left and right sides of the outer case part (main body part) and supported by a pair of support shafts in the outer case part, and are configured so that the ends on the opposite side to the side supported by the support shafts (hereinafter also referred to as "operation side ends") are rotated relative to the outer case part so as to approach each other, thereby moving both clamp parts to the open state.

[0004] Furthermore, the clamp sensor disclosed by the applicant includes a locking mechanism for preventing both clamp parts from being unintentionally shifted to an open state when in a closed state. In this case, the locking mechanism in this clamp sensor includes an operating piece and an opening prevention piece. In this locking mechanism, the opening prevention piece is moved between the base ends of both clamp parts in the closed state in response to a sliding operation of the operating piece relative to the outer case part, thereby restricting the rotation of both clamp parts (i.e., the transition from the closed state to the open state). In addition, the opening prevention piece is retracted from between the base ends of both clamp parts in response to a sliding operation of the operating piece in the opposite direction relative to the outer case part, thereby allowing the rotation of both clamp parts (the transition to the open state).

[0005] When using this clamp sensor, both clamp parts that have been switched to the closed state are switched to the open state. At this time, if the transition to the open state is restricted by the locking mechanism, the restriction is released by sliding the operating piece to move the opening prevention piece away from between the clamp parts. Next, both operating levers are rotated relative to the outer case part so that the operating side ends approach each other. At this time, the base ends of both clamp parts are pressed by both operating levers, causing both clamp parts to rotate against the biasing force of the coil springs and transition to the open state. In this state, the clamp target (conductor to be measured) is positioned between both clamp parts so as to pass between the tip ends of both clamp parts.

[0006] Next, the operating force applied to both operating levers is weakened. At this time, the biasing force of the coil spring rotates both clamp parts and transitions to the closed state. Next, the operating piece is slid to move the opening prevention piece between both clamp parts. This restricts the rotation of both clamp parts by the locking mechanism (opening prevention piece), and the transition from the closed state to the open state is restricted. As a result, even if the hand holding the clamp sensor touches both operating levers, both clamp parts are maintained in the closed state. After this, the measured quantity of the clamped object is measured based on the signal detected via the clamp sensor. Furthermore, when the measurement work is completed, both clamp parts are transitioned to the open state in the same manner as in the above operation method, and the clamp sensor is released from the clamped object. This completes the series of operations. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2004-125410 A (Pages 3-6, Figures 1-5) Summary of the Invention [Problem to be solved by the invention]

[0008] However, the clamp sensor disclosed by the applicant has the following problems that need to be improved.

[0009] Specifically, in the clamp sensor disclosed by the applicant, both clamp parts are supported by separate shafts in the outer case part, and both operation levers are supported by separate shafts in the outer case part. That is, in order to open and close both clamp parts, this clamp sensor requires a pair of operation levers formed separately from both clamp parts, and four shafts for supporting both clamp parts and both operation levers. In addition, the clamp sensor disclosed by the applicant is provided with a locking mechanism that can restrict the rotation of both clamp parts, that is, the transition of both clamp parts from the closed state to the open state, by moving the opening prevention piece between the base ends of both clamp parts that have been transitioned to the closed state. In this case, this locking mechanism is configured to include many members, such as the opening prevention piece and the operation piece, a driven piece that slides together with the operation piece, a screw for fixing the driven piece to the operation piece, and an excessive deformation prevention piece for preventing excessive deformation of the opening prevention piece. For this reason, this clamp sensor has a large number of components and the assembly work during manufacturing is complicated, which makes it difficult to reduce manufacturing costs.

[0010] In addition, in the lock mechanism of the clamp sensor disclosed by the applicant, the operating piece is arranged on the outer case part (main end part) assuming an operation method in which the clamp sensor is held in one hand and the operating piece is operated with the other hand, or the operating piece is operated with the thumb of the hand holding the clamp sensor. In this case, in this clamp sensor, the operating piece is arranged only on the front side of the outer case part (main body part). Therefore, when the clamp sensor is held carelessly with one hand, the operating piece may be present on the palm side of the holding hand, and in such a case, it becomes necessary to hold the clamp sensor again with the other hand before operating the operating piece. For this reason, it is preferable to improve this point.

[0011] Furthermore, in the clamp sensor disclosed by the applicant, the base ends of both clamp parts and the opening prevention piece of the locking mechanism are housed in the outer case. For this reason, in this clamp sensor, it is difficult to visually grasp whether the opening prevention piece has been moved between the base ends of both clamp parts (whether the clamp sensor is in a locked state or not). Therefore, when clamping the clamp object or when removing the clamp sensor from the clamp object, the clamp sensor may be mistakenly recognized as being in an unlocked state even though it is in a locked state, and both clamp parts may not be smoothly moved to an open state. In addition, the clamp sensor may be mistakenly recognized as being in a locked state even though it is in an unlocked state when the clamp object is clamped, and may be unintentionally moved to an open state, or the clamp sensor may be unintentionally moved to an open state due to external factors such as vibration, making it difficult to obtain accurate measurement values. For this reason, it is preferable to improve this point.

[0012] The present invention has been made in consideration of the above-mentioned problems that need to be improved, and has as its main object to provide a clamp sensor and measuring device that can reliably and easily switch between a locked state and an unlocked state, while reducing manufacturing costs, and that can reliably and easily recognize whether the state has been switched to the locked state or the unlocked state. [Means for solving the problem]

[0013] The clamp sensor according to claim 1 comprises a pair of clamp arms formed in an arc shape and constituting an annular sensor unit in a closed state in which tip ends are abutted against each other, and configured to be rotatable around a rotation axis disposed near the base ends of both clamp arms so as to move the tip ends closer to each other and away from each other, the clamp sensor comprising a pair of operating arms respectively provided at the base ends of both clamp arms and configured to be able to move the clamp arms to an open state in which the tip ends are separated from each other by rotating the operating arms around the rotation axis so as to move the clamp arms closer to each other, an arm rotation restricting member having one end pivotally supported by an arm, which allows relative rotation of the one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from the closed state to the open state in a first state in which the one operating arm is rotated with respect to the one operating arm so that the other end does not abut against the other operating arm, and which restricts relative rotation of the one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from the closed state to the open state in a second state in which the one operating arm is rotated with respect to the one operating arm so that the other end abuts against the other operating arm. The arm rotation restricting member and the other operating arm are formed such that, when viewed along the axial direction of the rotation shaft, a virtual straight line passing through the one end and the other end of the arm rotation restricting member in the second state is perpendicular or substantially perpendicular to a contact surface of the other operating arm against which the other end abuts. is. The clamp sensor of claim 2 is the clamp sensor of claim 1, wherein the arm rotation limiting member and the one of the operating arms are provided with a first member rotation limiting portion that limits the rotation of the arm rotation limiting member in the first state, and the first member rotation limiting portion has first permanent magnets respectively disposed on the arm rotation limiting member and the one of the operating arms, and is configured to be able to limit the rotation of the arm rotation limiting member by the attractive force of both first permanent magnets. The clamp sensor of claim 3 is the clamp sensor of claim 2, wherein the arm rotation limiting member and the other operating arm are provided with a second member rotation limiting portion that limits the rotation of the arm rotation limiting member in the second state, and the second member rotation limiting portion has second permanent magnets respectively arranged on the arm rotation limiting member and the other operating arm, and is configured to be able to limit the rotation of the arm rotation limiting member by the attractive force of both second permanent magnets. The clamp sensor of claim 4 is the clamp sensor of claim 1, wherein the arm rotation limiting member and the other operating arm are provided with a second member rotation limiting portion that limits the rotation of the arm rotation limiting member in the second state, and the second member rotation limiting portion has second permanent magnets respectively arranged on the arm rotation limiting member and the other operating arm, and is configured to be able to limit the rotation of the arm rotation limiting member by the attractive force of both second permanent magnets.

[0016] Claim 5 The described clamp sensor includes a pair of clamp arms that are formed in an arc shape and that constitute an annular sensor portion in a closed state with their tip ends abutted against each other, and that are configured to be rotatable around a rotation axis disposed near the base ends of both clamp arms so as to move the tip ends closer to and away from each other, and includes a pair of operating arms that are respectively provided at the base ends of both clamp arms and that are configured to be able to move the clamp arms to an open state in which the tip ends are separated from each other by rotating the operating arms around the rotation axis so as to move them closer to each other; an arm rotation restricting member having one end pivotally supported by one of the operating arms, and allowing relative rotation of the one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from the closed state to the open state in a first state in which the one operating arm is rotated with respect to the one operating arm so that the other end does not abut against the other operating arm, and restricting relative rotation of the one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from the closed state to the open state in a second state in which the one operating arm is rotated with respect to the one operating arm so that the other end abuts against the other operating arm The arm rotation restricting member and the one of the operation arms are provided with a first member rotation restricting portion that restricts rotation of the arm rotation restricting member in the first state, and the first member rotation restricting portion includes a first permanent magnet disposed on the arm rotation restricting member and the one of the operation arms, respectively, and is configured to be able to restrict rotation of the arm rotation restricting member by the attractive force of both the first permanent magnets. is. The clamp sensor of claim 6 is the clamp sensor of claim 5, wherein the arm rotation limiting member and the other operating arm are provided with a second member rotation limiting portion that limits the rotation of the arm rotation limiting member in the second state, and the second member rotation limiting portion has second permanent magnets respectively arranged on the arm rotation limiting member and the other operating arm, and is configured to be able to limit the rotation of the arm rotation limiting member by the attractive force of both second permanent magnets.

[0018] Claim 7 The clamp sensor described in the present application is a clamp sensor comprising a pair of clamp arms that are formed in an arc shape and that constitute an annular sensor section in a closed state in which their tip ends are abutted against each other, and that are configured so that the clamp arms can be rotated around a rotation axis disposed near the base ends of both clamp arms to move the tip ends closer to each other and away from each other. The clamp sensor further comprises a pair of operating arms that are respectively provided at the base ends of both clamp arms and that are configured so that the clamp arms can be moved to an open state in which the tip ends are separated from each other by rotating the operating arms around the rotation axis to move them closer to each other. and an arm rotation restricting member having one end pivotally supported by the clamp arm, which allows relative rotation of the one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from the closed state to the open state in a first state in which the one operating arm is rotated with respect to the one operating arm so that the other end does not abut against the other operating arm, and which restricts relative rotation of the one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from the closed state to the open state in a second state in which the one operating arm is rotated with respect to the one operating arm so that the other end abuts against the other operating arm. The arm rotation restricting member and the other operating arm are provided with a second member rotation restricting portion that restricts rotation of the arm rotation restricting member in the second state, and the second member rotation restricting portion includes a second permanent magnet disposed on the arm rotation restricting member and the other operating arm, respectively, and is configured to be able to restrict rotation of the arm rotation restricting member by the attractive force of both the second permanent magnets. is.

[0019] Claim 8 The clamp sensor according to the present invention comprises the following features: 7 In the clamp sensor described in any one of the above, both operating arms are formed so that a first distance between an end of one of the operating arms opposite the clamp arm side and the pivot shaft is shorter than a second distance between an end of the other operating arm opposite the clamp arm side and the pivot shaft, and the arm pivot limiting member is pivotally supported on one of the operating arms so that in the first state, the other end is located at the end of the one of the operating arms opposite the clamp arm side.

[0020] Claim 9 The measuring device according to the invention comprises the steps of: 8 and a measurement unit that measures a measured quantity of a clamp object clamped by the clamp sensor. Effect of the Invention

[0021] Claim 1 From 7 The described clamp sensor includes a pair of operating arms that are respectively provided extending from base ends of both clamp arms and that are configured to be able to move both clamp arms to an open state in which tip ends are separated from each other by rotating them about a rotation axis so as to bring them closer to each other, and an arm rotation restricting member that has one end pivotally supported by one of the operating arms and that allows relative rotation of one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from a closed state to an open state in a first state in which the operating arm is rotated relative to the other operating arm so that the other end does not abut against the other operating arm, and that restricts relative rotation of one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from a closed state to an open state in a second state in which the operating arm is rotated relative to the one operating arm so that the other end abuts against the other operating arm. 9 The described measuring device is configured to include the above clamp sensor and a measuring section.

[0022] Therefore, claim 1 From 7 The clamp sensor according to the invention and the claims 9 According to the described measuring device, one clamp arm and one operating arm are integrally formed, and the other clamp arm and the other operating arm are integrally formed, and a simple configuration is adopted in which the operation of both operating arms can be restricted only by an arm rotation restricting member pivotally supported on one operating arm, thereby sufficiently reducing the number of components of the clamp sensor, and thus the manufacturing cost of the clamp sensor can be sufficiently reduced. In addition, since the arm rotation restricting member is disposed between one operating arm and the other operating arm, the arm rotation restricting member can be rotated relative to one operating arm from either the front side or the back side of the clamp sensor. Therefore, even if the clamp sensor is held carelessly, the transition operation between the first state (unlocked state) and the second state (locked state) can be reliably and easily performed without having to hold it again with the other hand. In addition, since the rotational position of the arm rotation restricting member relative to one of the operating arms can be visually confirmed from either the front side or the back side of the clamp sensor, it is possible to reliably and easily recognize whether it is in the first state (unlocked state) or the second state (locked state). This makes it possible to preferably avoid a situation in which the sensor is unintentionally shifted to the open state due to a mistaken belief that it is in the second state, or an unintentional shift to the open state due to external factors such as vibration, and makes it possible to obtain accurate measurement values.

[0023] In addition, claims 1 to 4According to the described clamp sensor and a measuring device equipped with the clamp sensor, the arm rotation limiting member and the other operating arm are formed so that, when viewed along the axial direction of the rotation shaft, a virtual straight line passing through one end and the other end of the arm rotation limiting member in the second state is perpendicular or nearly perpendicular to the abutment surface of the other operating arm against which the other end abuts.Therefore, even if a force is applied in a direction that brings both operating arms closer to each other when the arm rotation limiting member is in the second state (locked state), the force applied from one operating arm to the other operating arm via the arm rotation limiting member is applied perpendicular or nearly perpendicular to the abutment surface of the other operating arm. As a result, slippage of the other end of the arm rotation limiting member along the abutment surface, i.e., slippage of the arm rotation limiting member relative to the other operating arm, is unlikely to occur, and the state in which the other end of the arm rotation limiting member is abutted against the abutment surface of the other operating arm, i.e., the second state (locked state), can be preferably maintained.

[0024] Also, claims 2,3,5,6 According to the described clamp sensor and a measuring device equipped with that clamp sensor, a first member pivoting limiting portion that limits the rotation of the arm pivoting limiting member in a first state is provided on the arm pivoting limiting member and one of the operating arms, thereby making it possible to preferably avoid a situation in which, when both operating arms are operated, the arm pivoting limiting member rotates relative to one of the operating arms, causing the other end of the arm pivoting limiting member to come into contact with the other operating arm, thereby hindering operation of both operating arms.

[0025] Also, claims 2,3,5,6According to the clamp sensor described above and the measuring device equipped with the clamp sensor, the arm rotation restricting member and one of the operation arms are provided with first permanent magnets, and the first member rotation restricting portion is configured to be able to restrict the rotation of the arm rotation restricting member by the attractive force of both first permanent magnets, so that it is possible to preferably restrict unintended rotation of the arm rotation restricting member relative to one of the operation arms, even with a relatively simple configuration. Also, unlike the case where a mechanical positioning structure such as a ball notch mechanism is employed, there are no parts that wear out, so the first member rotation restricting portion can function preferably over a long period of time.

[0026] In addition, claims 3,4,6,7 According to the described clamp sensor and a measuring device equipped with the clamp sensor, a second member rotation limiting portion that limits the rotation of the arm rotation limiting member in the second state is provided on the arm rotation limiting member and the other operating arm, thereby making it possible to preferably avoid a situation in which the arm rotation limiting member that has been transitioned to the second state (locked state) unintentionally rotates relative to one of the operating arms, making it impossible to maintain both clamp arms in a closed state.

[0027] In addition, claims 3,4,6,7 According to the clamp sensor described above and the measuring device equipped with the clamp sensor, the arm rotation restricting member and the other operating arm are provided with second permanent magnets, and the second member rotation restricting portion is configured to be able to restrict the rotation of the arm rotation restricting member by the attractive force of both second permanent magnets, so that it is possible to preferably restrict unintended rotation of the arm rotation restricting member relative to one operating arm, even with a relatively simple configuration. Also, unlike the case where a mechanical positioning structure such as a ball notch mechanism is employed, there are no parts that wear out, so the second member rotation restricting portion can function preferably for a long period of time.

[0028] In addition, claims 8According to the clamp sensor and the measuring device including the clamp sensor, the two operating arms are formed so that the first distance between the end of one operating arm opposite to the clamp arm side and the pivot shaft is shorter than the second distance between the end of the other operating arm opposite to the clamp arm side and the pivot shaft, and the arm rotation restricting member is pivotally supported on one operating arm so that the other end is located at the end of one operating arm opposite to the clamp arm side in the first state. Therefore, when holding the clamp sensor with one hand, the index finger, middle finger, ring finger and little finger are placed on the outer edge of the other operating arm, and the thumb can be placed in a natural position on the end of the outer edge of the other operating arm opposite to the clamp arm side. This makes it possible to reliably and more easily open and close both clamp arms. In addition, after both clamp arms are moved to the closed state by operating both operating arms, the other end of the arm rotation restricting member located at the end of one operating arm opposite to the clamp arm side can be operated with the thumb to smoothly move the arm rotation restricting member to the second state (locked state). [Brief description of the drawings]

[0029] [Figure 1] FIG. 2 is a configuration diagram of the measuring device 1 as viewed from the front side. [Diagram 2] 1 is a perspective view of the appearance of the clamp sensor 2 in a state in which the transition of the sensor unit 10 to an open state is restricted. [Diagram 3] 1 is an external perspective view of the clamp sensor 2 in a state in which the sensor unit 10 is permitted to transition to an open state. [Figure 4] 1 is an external perspective view of the clamp sensor 2 in a state in which the sensor unit 10 has been shifted to an open state. [Diagram 5] 1 is a cross-sectional view of an operation unit 20 of a clamp sensor 2 in a state in which a sensor unit 10 is permitted to transition to an open state. [Figure 6] 1 is a cross-sectional view of an operation unit 20 of a clamp sensor 2 in a state in which the transition of a sensor unit 10 to an open state is restricted. [Figure 7]1 is an external view of the clamp sensor 2 when the sensor unit 10 is permitted to transition to the open state, as viewed along the axial direction of the rotation shaft 30. FIG. [Figure 8] 1 is an external view of the clamp sensor 2 when the sensor unit 10 is shifted to an open state, as viewed along the axial direction of the rotation shaft 30. FIG. [Figure 9] 1 is an external view of the clamp sensor 2 when the transition of the sensor unit 10 to the open state is restricted, as viewed along the axial direction of the rotation shaft 30. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, embodiments of a clamp sensor and a measuring device will be described with reference to the accompanying drawings.

[0031] 1 is a non-contact current measuring device, which is an example of a "measuring device", and is configured to detect a magnetic field generated around clamping object X (such as an electric wire) when a current flows through the clamping object X, and to measure a current value (an example of a "measured quantity") of the current flowing through the clamping object X based on the magnitude of the detected magnetic field. Specifically, the measuring device 1 is configured with a clamp sensor 2 and a measuring device main body 3.

[0032] The clamp sensor 2 is an example of a "clamp sensor" and, as shown in Figs. 2 to 4, includes a sensor unit 10, an operation unit 20, a rotating shaft 30 (see Figs. 5 to 9), and a signal cable 40. The sensor unit 10 includes clamp arms 11 and 12 (an example of a "pair of clamp arms") formed in an arc shape, and is configured to form a ring-shaped magnetic detection circuit (not shown) in a closed state in which the ends 11a and 12a are abutted against each other and the ends 11b and 12b are abutted against each other, as shown in Figs. 2 and 3. In this case, in the clamp sensor 2 of this example, the ends 11a and 12a correspond to the "tip end" and the ends 11b and 12b correspond to the "base end".

[0033] The operating unit 20 includes an operating arm 21 extending from the end 11b of the clamp arm 11 (integrally formed with the clamp arm 11), and an operating arm 22 extending from the end 12b of the clamp arm 12 (integrally formed with the clamp arm 12) (one example of a "pair of operating arms"). That is, in the clamp sensor 2 of this example, one rod-shaped member is formed by connecting the end 11b of the clamp arm 11 and the end 21a of the operating arm 21, and another rod-shaped member is formed by connecting the end 12b of the clamp arm 12 and the end 22a of the operating arm 22.

[0034] In this case, the clamp sensor 2 of this example is configured so that both clamp arms 11, 12 and operating arms 21, 22 can be rotated around a rotation shaft 30 (an example of a "rotation shaft") disposed at end 21a of operating arm 21 and end 22a of operating arm 22 (an example of "vicinity of the base ends of both clamp arms") as shown in Figures 7 to 9. Also, in this clamp sensor 2, as shown in Figures 4 and 8, by rotating the operating arms 21, 22 around the rotation shaft 30 so as to bring the operating arms 21, 22 (end 21b of operating arm 21 and end 22b of operating arm 22) closer to each other, both clamp arms 11, 12 can be shifted to an open state in which ends 11a, 12a are separated from each other and ends 11b, 12b are separated from each other.

[0035] In the clamp sensor 2 of this example, the ends 21b, 22b correspond to the "ends opposite to the clamp arm side." In the actual clamp sensor 2, a biasing member that biases the operating arms 21, 22 in a direction separating them from each other is housed in the operating arms 21, 22, and a sensor board provided between the magnetic detection circuit in the sensor unit 10 and the signal cable 40 is housed in the operating arm 22; however, to facilitate understanding of the configuration of the clamp sensor 2, illustrations and detailed explanations of these are omitted.

[0036] Also, in this clamp sensor 2, as shown in FIG. 7, both operating arms 21, 22 are formed so that the distance L21 (an example of a "first distance") between the end 21b of operating arm 21 (an example of "one operating arm") and the pivot shaft 30 is shorter than the distance L22 (an example of a "second distance") between the end 22b of operating arm 22 (an example of "the other operating arm") and the pivot shaft 30.

[0037] In this case, as shown in Figures 7 to 9, the operating arms 21, 22 in the clamp sensor 2 of this example are formed so that an outer edge E21o on the side opposite to the operating arm 22 side of the operating arm 21 and an outer edge E22o on the side opposite to the operating arm 21 side of the operating arm 22 are both curved in the same direction when viewed along the axial direction of the rotating shaft 30. Specifically, the operating arms 21, 22 are formed so that the outer edge portions E21o, E22o are curved in a direction from the operating arm 21 toward the operating arm 22 (downward in Figures 7 to 9) when viewed along the axial direction.

[0038] In this case, in the clamp sensor 2 of this example, the outer edge E22o of the operating arm 22 is curved with a gentle curvature according to the arc-shaped positions of the middle phalanges of the four fingers of the index finger, middle finger, ring finger, and little finger when an adult holds the clamp sensor 2 in one hand. Also, the outer edge E21o of the operating arm 21 is gently curved with substantially the same shape (substantially the same curvature) as the outer edge E22o of the operating arm 22.

[0039] In addition, when viewed along the axial direction, the operating arms 21, 22 in the clamp sensor 2 of this example are formed in a curved shape such that both the outer edge E21i of the operating arm 21 on the operating arm 22 side and the outer edge E22i of the operating arm 22 on the operating arm 21 side are curved in the same direction as the outer edge E21o of the operating arm 21 and the outer edge E22o of the operating arm 22 (in this example, the direction from the operating arm 21 to the operating arm 22).

[0040] Furthermore, when viewed along the axial direction, the operating arms 21, 22 of this example have the same shape at the portion of the outer edge E21i facing the outer edge E22i and at the portion of the outer edge E22i facing the outer edge E21i, so that both clamp arms 11, 12 have complementary shapes. As a result, in the clamp sensor 2 of this example, as shown in Fig. 8, when both clamp arms 11, 12 are moved to the open state (when both operating arms 21, 2 are moved closer to each other), the outer edge E21i of the operating arm 21 and the outer edge E22i of the operating arm 22 are in almost intimate contact with each other, so that no gap is generated between both operating arms 21, 22.

[0041] 2 to 4, in the clamp sensor 2 of this example, a rotation restricting member 23 (an example of an "arm rotation restricting member") is attached to the operating arm 21. Specifically, as an example, the rotation restricting member 23 has an end 23a (an example of an "end") pivotally supported at a midpoint between both ends 21a, 21b of the operating arm 21 so as to be rotatable relative to the operating arm 21.

[0042] As shown in Figures 7 and 8, this rotation restricting member 23 allows relative rotation of the operating arm 21 with respect to the operating arm 22 in a direction that transitions the clamp arms 11, 12 from a closed state to an open state when the end 23b (an example of the "other end") is rotated with respect to the operating arm 21 so that it does not abut against the operating arm 22 (unlocked state: as an example, a state in which the end 23b is rotated so that it is positioned on the side of end 21b of the operating arm 21: an example of the "first state").

[0043] In this case, in the clamp sensor 2 of this example, the rotation restricting member 23 is pivotally supported by the operating arm 21 so that the end 23b is located at the end 21b of the operating arm 21 (an example of "an end of one operating arm on the opposite side to the clamp arm side") in the unlocked state. In addition, in the clamp sensor 2 of this example, as shown in Fig. 5, the pivotal support position of the rotation restricting member 23 relative to the operating arm 21, the length of the rotation restricting member 23, the shape of the rotation restricting member 23, etc. are specified so that in the unlocked state, the rotation restricting member 23 is integrated with the operating arm 21 and becomes like a single rod, and the rotation restricting member 23 is not present between the operating arms 21 and 22. As a result, in the clamp sensor 2 of this example, it is possible to bring the outer edge E21i of the operating arm 21 and the outer edge E22i of the operating arm 22 sufficiently close to each other (bringing the outer edges E21i and E22i into close contact with each other) when the clamp arms 11 and 12 are moved to the open state.

[0044] Furthermore, when the rotation restricting member 23 is rotated relative to the operating arm 21 so that the end portion 23b abuts against the outer edge portion E22i of the operating arm 22 (locked state: an example of the "second state") as shown in Figure 9, the rotation restricting member 23 restricts the relative rotation of the operating arm 21 with respect to the operating arm 22 in a direction that transitions the clamp arms 11, 12 from a closed state to an open state.

[0045] In this case, in the clamp sensor 2 of this example, as shown in Figure 6, when viewed along the axial direction of the pivot shaft 30, the rotation restricting member 23 and the operating arm 22 are formed so that a virtual straight line passing through both end portions 23a, 23b of the rotation restricting member 23 in the locked state (dotted line L1 shown in the same figure: an example of a "virtual straight line") is perpendicular (or nearly perpendicular) to the abutted surface F22 (a surface along the two-dotted line L2 shown in the same figure: an example of an "abutted surface") against which the end portion 23b (abutment surface F23) of the rotation restricting member 23 abuts on the operating arm 22.

[0046] 5, in the clamp sensor 2 of this example, a magnet M21 is disposed at the end 21b of the operating arm 21, and a magnet M23 is disposed at the end 23b of the rotation restricting member 23. As a result, in the clamp sensor 2 of this example, when the rotation restricting member 23 is shifted to the unlocked state, the end 23b of the rotation restricting member 23 is maintained in a state in which it is attracted to the end 21b of the operating arm 21 by the attractive forces of both magnets M21 and M23, and the rotation of the rotation restricting member 23 relative to the operating arm 21 is restricted. In this example, the magnets M21 and M23 correspond to a "first permanent magnet", and the magnets M21 and M23 constitute a "first member rotation restricting portion".

[0047] 6, in the clamp sensor 2 of this example, a magnet M22 is disposed in the middle of both ends 22a, 22b of the operation arm 22. As a result, in the clamp sensor 2 of this example, when the rotation restricting member 23 is shifted to the locked state, the end 23b of the rotation restricting member 23 is kept attracted to E22i of the operation arm 22 by the attraction force between the magnet M22 and the magnet M23 of the rotation restricting member 23, and the rotation of the rotation restricting member 23 relative to the operation arm 21 (i.e., release of the locked state) is restricted. In this example, the magnets M22, M23 correspond to a "second permanent magnet", and the magnets M22, M23 constitute a "second member rotation restricting portion" (an example of a configuration in which the magnet M23 is shared by the "first member rotation restricting portion" and the "second member rotation restricting portion").

[0048] In addition, in the clamp sensor 2 of this example, the lengths and shapes of both clamp arms 11, 12 and both operating arms 21, 22 are specified so that the operating unit 20 is within the range of the maximum width W10 of the sensor unit 10 in the closed state (so that the maximum width W20 of the operating unit 20 is less than or equal to the maximum width W10 of the sensor unit 10), as shown in Figures 7 and 9.

[0049] In the clamp sensor 2 of this example, a signal cable 40 (an example of a "connection cable") for connecting the clamp sensor 2 to the measuring device main body 3 is connected to the above-mentioned sensor board within the operating arm 22, and is also drawn out from the end 22b of the operating arm 22 to the outside of the operating arm 22, as shown in Figures 2 to 4. Furthermore, a connection connector (not shown) for connecting to the measuring device main body 3 is connected to the tip of the signal cable 40.

[0050] On the other hand, the measuring device main body 3 is, for example, integrally configured with components corresponding to the "outside" and "measurement unit", an "operation unit" having multiple operation switches for setting measurement conditions, etc., and a "display unit" for displaying measurement results, and is configured so that the signal cable 40 of the clamp sensor 2 can be connected / disconnected. This measuring device main body 3 contains the signal cable 40 and a measurement circuit that is connected to the sensor unit 10 (magnetic detection circuit) of the clamp sensor 2 via the above-mentioned sensor board. Note that instead of such a configuration of the measuring device main body 3, the components corresponding to the "outside" and "measurement unit" can be configured separately from the "operation unit" and "display unit".

[0051] In this measuring device 1, when it is stored or transported, for example, the clamp sensor 2 (signal cable 40) is removed from the measuring device main body 3, and the rotation restricting member 23 is shifted to the locked state as shown in Figures 2 and 9. This allows the clamp sensor 2 to be stored or transported in a smart state in which the operation unit 20 is present within the range of the maximum width W10 of the sensor unit 10 in the closed state as described above, and by restricting the sensor unit 10 from unintentionally shifting to the open state, it is possible to preferably prevent a foreign object from being caught between the ends 11a, 12b of the clamp arms 11, 12, which would cause deformation or damage to the clamp arms 11, 12.

[0052] On the other hand, when measuring the current value of the current flowing through the clamp target X with this measuring device 1, first, the clamp sensor 2 (signal cable 40) is connected to the measuring device main body 3. Next, when the rotation restricting member 23 has been shifted to the locked state as described above, the rotation restricting member 23 is rotated with respect to the operating arm 21 to shift to the unlocked state as shown in Figures 3 and 7. This allows the operation of shifting both clamp arms 11, 12 from the closed state to the open state.

[0053] In this case, in the clamp sensor 2 of this example, by rotating the rotation restricting member 23 with respect to the operating arm 21 until the end 23b of the rotation restricting member 23 is positioned at the end 21b of the operating arm 21, the attractive force between the magnet M21 disposed at the end 21b and the magnet M23 disposed at the end 23b restricts unintended rotation of the rotation restricting member 23 with respect to the operating arm 21. This makes it possible to avoid a situation in which the rotation restricting member 23 in the unlocked state unintendedly rotates with respect to the operating arm 21, hindering an operation described below for bringing both operating arms 21, 22 closer to each other.

[0054] Next, as an example, the clamp sensor 2 is held in one hand by placing the operating part 20 of the clamp sensor 2 on the palm, bending the index finger, middle finger, ring finger, and little finger, placing the middle phalanges of each finger on the outer edge E22o of the operating arm 22, and placing the pad of the thumb on the outer edge E21o of the operating arm 21. Next, the operating arm 21 is operated by bringing the thumb closer to the index finger. At this time, the operating arm 21 is rotated about the rotating shaft 30 against the biasing force of a biasing member (not shown), and the operating arm 21 is brought closer to the operating arm 22. In addition, with the rotation of the operating arm 21 relative to the operating arm 22, the clamp arm 11 formed integrally with the operating arm 21 is rotated relative to the clamp arm 12 formed integrally with the operating arm 22. As a result, as shown in Figures 4 and 8, the sensor unit 10 is transitioned from a closed state to an open state, so that the end 11a of the clamp arm 11 and the end 12a of the clamp arm 12 are separated from each other, and the end 11b of the clamp arm 11 and the end 12b of the clamp arm 12 are separated from each other.

[0055] In this case, in the clamp sensor 2 of this example, the outer edge E22o of the operating arm 22 is curved with a gentle curvature according to the arc-shaped positions of the middle phalanges of the four fingers, the index finger, the middle finger, the ring finger, and the little finger. Therefore, the force applied to the operating arm 22 when the operating arm 21 rotates relative to the operating arm 22 (the restoring force of the biasing member) can be received almost evenly by the four fingers, so that even a person with a weak grip can adequately support the operating arm 21 and can suitably maintain the state in which the four fingers are placed on the outer edge E22o of the operating arm 22 (suitably preventing the four fingers from slipping relative to the operating arm 22).

[0056] In the clamp sensor 2 of this embodiment, the outer edge E21o of the operating arm 21 is gently curved in the same direction with approximately the same shape (approximately the same curvature) as the outer edge E22o of the operating arm 22. Therefore, the force (the restoring force of the biasing member) applied to the operating arm 21 when the operating arm 21 rotates relative to the operating arm 22 can be received approximately evenly within a sufficiently wide area of ​​the thumb pad, so that the operating arm 21 can be favorably supported without feeling pain in the thumb pad, and the thumb can be favorably maintained in a state of being placed on the outer edge E21o of the operating arm 21 (favorably preventing the thumb from slipping relative to the operating arm 21). In addition, since the outer edges E21o and E22o are curved in the same direction, when the operating arms 21 and 22 are brought close to each other, the distance between the outer edges E21o and E22o becomes sufficiently short throughout the entire longitudinal direction of the operating arms 21 and 22. This allows even small hands to reliably and easily maintain both operating arms 21, 22 close to each other.

[0057] Furthermore, as described above, in the clamp sensor 2, the portion of the outer edge E21i of the operating arm 21 facing the outer edge E22i of the operating arm 22 and the portion of the outer edge E22i facing the outer edge E21i have the same shape, and are configured so that when the sensor unit 10 is operated to transition to the open state, both outer edges E21i, E22i are in almost intimate contact with each other, resulting in no gap between both operating arms 21, 22. Therefore, even if an unnecessarily strong force is applied to both operating arms 21, 22 in a direction to bring them closer to each other, a sufficiently wide area of ​​the outer edge E21i of the operating arm 21 and the outer edge E22i of the operating arm 22 are in contact with each other, dispersing the force applied to the contact portion between the outer edge E21i and the outer edge E22i, and therefore damage or deformation of the operating arms 21, 22 can be suitably avoided.

[0058] In this case, unlike the clamp sensor 2 of this example, in a configuration in which the shapes of the opposing portions of the outer edges E21i, E22i are different, i.e., in a configuration (not shown) in which the outer edges E21i, E22i are in point contact at some point in the longitudinal direction of the operating arms 21, 22 when the two operating arms 21, 22 are brought close to each other, a force is applied that tries to pull apart the support portions of the pivot shaft 30 of the two operating arms 21, 22, with the point contact portion of the outer edges E21i, E22i as a fulcrum, which may result in deformation or damage to the pivot shaft 30. In contrast, in the clamp sensor 2 of this example, the opposing portions of the outer edge portions E21i, E22i have the same shape, and when the two operating arms 21, 22 are brought close to each other, no portion corresponding to the above-mentioned "fulcrum" is created, and the outer edge portions E21i, E22i are in surface contact, thereby preferably avoiding deformation or damage to the pivot shaft 30.

[0059] Next, the clamp target X is positioned between the clamp arms 11, 12 by passing it between the ends 11a, 12a of both clamp arms 11, 12 (the clamp sensor 2 is moved so that the clamp target X is positioned between the clamp arms 11, 12). Next, the force of the thumb operating the operating arm 21 is reduced.

[0060] At this time, the operating arm 21 is rotated about the rotation shaft 30 by the biasing force of a biasing member (not shown) in a direction opposite to that during operation for the purpose of transitioning to the above-mentioned open state, and the operating arm 21 is moved away from the operating arm 22. In addition, with the rotation of the operating arm 21 in the opposite direction relative to the operating arm 22, the clamp arm 11 formed integrally with the operating arm 21 is rotated in the opposite direction relative to the clamp arm 12 formed integrally with the operating arm 22 in a direction opposite to that during operation for the purpose of transitioning to the open state. As a result, as shown in Figures 3 and 7, the sensor unit 10 is transitioned from the open state to the closed state, and the end 11a of the clamp arm 11 and the end 12a of the clamp arm 12 come into contact with each other, and the end 11b of the clamp arm 11 and the end 12b of the clamp arm 12 come into contact with each other, and a ring-shaped magnetic detection circuit is formed in the sensor unit 10.

[0061] Next, the rotation restricting member 23 is rotated with respect to the operating arm 21 against the attraction force of the magnets M21, M23, and is shifted to a locked state as shown in Figs. 2 and 9. Specifically, the rotation restricting member 23 is rotated with respect to the operating arm 21 so that the end 23b (contact surface F23) of the rotation restricting member 23 abuts against the abutted surface F22 at the outer edge E22i of the operating arm 22. This restricts the operation of both operating arms 21, 22 in a direction to approach each other, and the sensor unit 10 is maintained in a closed state. In this case, in the clamp sensor 2 of this example, the end 23b of the rotation restricting member 23 is maintained in abutment against the outer edge E22i of the operating arm 22 due to the attraction force between the magnet M22 arranged on the operating arm 22 and the magnet M23 arranged on the rotation restricting member 23.

[0062] In the clamp sensor 2 of this example, when the clamp sensor 2 in which the rotation restricting member 23 has been shifted to the locked state is viewed along the axial direction of the rotation shaft 30, a virtual line (a virtual line along the extension direction of the rotation restricting member 23: a dashed line L1 shown in FIG. 6) passing through both ends 23a, 23b of the rotation restricting member 23 is perpendicular (or nearly perpendicular) to a contact surface F22 (a dashed line L2 shown in FIG. 6) with which the end 23b of the rotation restricting member 23 abuts on the operating arm 22. For this reason, when a force is applied in a direction that brings the two operating arms 21, 22 closer to each other, the contact surface F23 of the rotation restricting member 23 is pressed perpendicularly (or nearly perpendicularly) against the contact surface F22 of the operating arm 22, so that the contact surface F23 is less likely to slip along the contact surface F22 (i.e., the end 23b is less likely to slip relative to the operating arm 22). As a result, the state in which the end 23b of the rotation restricting member 23 abuts against the outer edge portion E22i of the operating arm 22 is maintained even more suitably.

[0063] Therefore, in the clamp sensor 2 of this example, it is possible to preferably prevent a situation in which the rotation restricting member 23, which has been switched to the locked state, unintentionally rotates relative to the operating arm 21 and operates in a direction that brings both operating arms 21, 22 closer to each other. This restricts the operation of switching both clamp arms 11, 12 from the closed state to the open state, and maintains the sensor unit 10 in the closed state. With the above, clamping of the clamp object X by the clamp sensor 2 is completed.

[0064] Thereafter, the measurement process is started by operating the operation unit of the measurement device main body 3. At this time, the magnetic field generated around the clamp object X (such as an electric wire) due to the current flowing through the clamp object X is detected by the clamp sensor 2, and the measurement device main body 3 calculates (measures) the current value of the current flowing through the clamp object X based on the magnitude of the detected magnetic field. As a result, the current value as the measurement result is displayed on the display unit of the measurement device main body 3, and a series of measurement operations is completed.

[0065] Furthermore, when the measurement work is completed, the clamp target X is moved from between both clamp arms 11, 12 in the reverse order to the clamp work described above (the clamp sensor 2 is removed from the clamp target X). Furthermore, when transporting or storing, as described above, the rotation restricting member 23 is shifted to the locked state and the clamp sensor 2 is removed from the measuring device main body 3. With the above, a series of operations is completed.

[0066] In addition, in the clamp sensor 2 of this example, instead of the operation method of holding both operating arms 21, 22 with one hand by placing five fingers on both operating arms 21, 22 as described above, both operating arms 21, 22 can be held by pinching them with the thumb and index finger (or pinching them with the thumb, index finger, and middle finger). In this case, since the distance between the outer edges E21o and E22o of the clamp sensor 2 of this example is sufficiently short, the clamp sensor 2 can be reliably and easily held by pinching both operating arms 21, 22 with two fingers or two fingers, and the clamp arms 11, 12 can be reliably and easily opened and closed. As a result, compared to the case of holding the clamp sensor 2 with one hand by placing five fingers on both operating arms 21, 22, the clamp sensor 2 can be held and opened and closed in various postures without forcibly bending and straightening the wrist or elbow when clamping the clamp object X or removing it from the clamp object X. Therefore, even when the clamp object X is located in a narrow space or at a high or low place, the clamp sensor 2 can be moved toward / away from the clamp object X in various positions and opened / closed in various positions, so that various clamp objects X can be reliably and easily clamped and removed.

[0067] In addition, in the clamp sensor 2 of this example, unlike a configuration in which the outer edges E21o, E22o are curved in opposite directions so as to be largely separated from each other at the center in the longitudinal direction of both operating arms 21, 22, or a configuration in which the outer edges E21o, E22o are linear along the longitudinal direction of both operating arms 21, 22, the outer edges E21o, E22o are curved in the same direction, so that even when the clamp sensor 2 is held with only two or three fingers, the fingers placed on the inside of the curved shape are less likely to slip relative to the operating arm (in this example, the operating arm 21). Therefore, the fingers placed on the outside of the curved shape are also less likely to slip relative to the operating arm (in this example, the operating arm 22). As a result, the clamp sensor 2 can be reliably held with only two or three fingers, and unintentional dropping of the clamp sensor 2 can be suitably prevented.

[0068] In this manner, in the clamp sensor 2, the pair of operating arms 21, 22 are respectively provided to extend from the ends 11b, 12b of the clamp arms 11, 12 and are configured to be able to move the clamp arms 11, 12 to an open state in which the ends 11a, 12a are spaced apart from each other by rotating the operating arms 21, 22 about the rotating shaft 30 so as to bring them closer to each other; and a rotation restricting member 23 that permits relative rotation of the operating arm 21 with respect to the operating arm 22 in a direction that transitions both clamp arms 11, 12 from a closed state to an open state in a "second state (locked state)" in which the operating arm 21 is rotated with respect to the operating arm 21 so that the end 23b abuts against the operating arm 22. The measuring device 1 is also configured with the clamp sensor 2 and the measuring device main body 3 described above.

[0069] Therefore, according to the clamp sensor 2 and the measuring device 1, the clamp arm 11 and the operating arm 21 are integrally formed, and the clamp arm 12 and the operating arm 22 are integrally formed, and a simple configuration is adopted in which the operation of the operating arms 21, 22 can be restricted only by the rotation restricting member 23 pivotally supported by the operating arm 21. This allows the number of components of the clamp sensor 2 to be sufficiently reduced, and therefore the manufacturing cost of the clamp sensor 2 can be sufficiently reduced. Furthermore, since the rotation restricting member 23 is disposed between the operating arms 21 and 22, the rotation restricting member 23 can be rotated relative to the operating arm 21 from either the front side or the back side of the clamp sensor 2. Therefore, even if the clamp sensor 2 is held carelessly, the transition operation between the "first state (unlocked state)" and the "second state (locked state)" can be reliably and easily performed without having to hold it again with the other hand. In addition, since the rotational position of the rotation restricting member 23 relative to the operating arm 21 can be seen from either the front side or the back side of the clamp sensor 2, it is possible to reliably and easily recognize whether the state is the "first state (unlocked state)" or the "second state (locked state)." This makes it possible to preferably avoid a situation in which the state is unintentionally shifted to the open state due to a mistaken belief that the state is the "second state," or an unintentional shift to the open state due to external factors such as vibration, and makes it possible to obtain accurate measurement values.

[0070] Furthermore, according to the clamp sensor 2 and the measuring device 1, the rotation restricting member 23 and the operating arm 22 are formed so that, when viewed along the axial direction of the rotating shaft 30, a "virtual straight line (one-dot chain line L1 in FIG. 6)" passing through the end 23a and the end 23b of the rotation restricting member 23 is perpendicular or nearly perpendicular to the abutment surface F22 (the surface of the two-dot chain line L2) with which the end 23b of the operating arm 22 abuts. This makes it possible to bring both operating arms 21, 22 close to each other when the rotation restricting member 23 is in the "second state (locked state)". Even if a force is applied in a direction that causes the operating arm 22 to rotate, the force applied from the operating arm 21 to the pivoting limiting member 23 is applied perpendicular or nearly perpendicular to the abutment surface F22 at the outer edge E22i of the operating arm 22, so that slippage of the end 23b (abutment surface F23) along the abutment surface F22, i.e., slippage of the pivoting limiting member 23 relative to the operating arm 22, is unlikely to occur, and therefore the state in which the end 23b of the pivoting limiting member 23 is abutted against the outer edge E22i (abutment surface F22) of the operating arm 22, i.e., the "second state (locked state)" can be preferably maintained.

[0071] Furthermore, according to this clamp sensor 2 and measuring device 1, a "first member rotation regulating section (in this example, magnets M21, M23)" that regulates the rotation of the rotation regulating member 23 in the "first state (unlocked state)" is provided on the rotation regulating member 23 and the operating arm 21. This makes it possible to preferably avoid a situation in which, when the operating arms 21, 22 are operated, the rotation regulating member 23 rotates relative to the operating arm 21 and the end 23b comes into contact with the operating arm 22, thereby hindering the operation of the operating arms 21, 22.

[0072] Furthermore, according to this clamp sensor 2 and measuring device 1, the rotation restricting member 23 and the operating arm 21 are provided with a "first permanent magnet (magnets M21, M23)," respectively, and the "first member rotation restricting portion" is configured to be able to restrict the rotation of the rotation restricting member 23 by the attractive force of the magnets M21, M23, so that unintended rotation of the rotation restricting member 23 relative to the operating arm 21 can be suitably restricted, despite the relatively simple configuration. Furthermore, unlike the case where a mechanical positioning structure such as a ball notch mechanism is employed, there are no parts that wear out, so the "first member rotation restricting portion" can function suitably over a long period of time.

[0073] Furthermore, according to this clamp sensor 2 and measuring device 1, by providing a "second member rotation regulating section (in this example, magnets M22, M23)" that regulates the rotation of the rotation regulating member 23 in the "second state (locked state)" on the rotation regulating member 23 and the operating arm 22, it is possible to preferably avoid a situation in which the rotation regulating member 23, which has been transitioned to the "second state (locked state)", unintentionally rotates relative to the operating arm 21, making it impossible to maintain both clamp arms 11, 12 in the closed state.

[0074] Furthermore, according to this clamp sensor 2 and measuring device 1, a "second member rotation restricting portion" is configured that includes "second permanent magnets (magnets M22, M23)" disposed on the rotation restricting member 23 and the operating arm 22, respectively, and that is capable of restricting the rotation of the rotation restricting member 23 by the attractive forces of both magnets M22, M23, so that unintended rotation of the rotation restricting member 23 relative to the operating arm 21 can be suitably restricted, despite the relatively simple configuration. Furthermore, unlike the case where a mechanical positioning structure such as a ball notch mechanism is employed, there are no parts that wear out, so the "second member rotation restricting portion" can function suitably over a long period of time.

[0075] Moreover, according to the clamp sensor 2 and the measuring device 1, the two operating arms 21, 22 are formed so that the "first distance" (distance L21 in FIG. 7) between the end 21b of the operating arm 21 on the side opposite to the clamp arm 11 side and the rotary shaft 30 is shorter than the "second distance" (distance L22) between the end 22b of the operating arm 22 on the side opposite to the clamp arm 12 side and the rotary shaft 30, and the rotation restricting member 23 is pivotally supported on the operating arm 21 so that the end 23b of the rotation restricting member 23 is located at the end 21b of the operating arm 21 in the "first state (unlocked state)". As a result, when the clamp sensor 2 is held in one hand, with the index finger, middle finger, ring finger, and little finger placed on the outer edge E22o of the operating arm 22, the thumb can be placed in a natural position on the end 21b side of the outer edge E22o of the operating arm 22. This makes it possible to reliably and more easily open and close both clamp arms 11, 12. In addition, after both clamp arms 11, 12 are transitioned to the closed state by operating both operating arms 21, 22, the rotation limiting member 23 (end 23b) located at end 21b of the operating arm 21 can be operated with the thumb to smoothly transition the rotation limiting member 23 to the "second state (locked state)".

[0076] It should be noted that the configurations of the "clamp sensor" and the "measuring device" are not limited to the examples of the configurations of the clamp sensor 2 and the measuring device 1 described above.

[0077] For example, the clamp sensor 2 has been described with the configuration in which the operating arms 21, 22 are formed so that the outer edge portions E21o, E22o of the operating arms 21, 22 are curved in the same direction when viewed along the axial direction of the rotating shaft 30, but the outer edge portions E21o, E22o may be curved in different directions, or one or both may be non-curved (straight, angular, etc.) (not shown). Similarly, one or both of the outer edge portions E21i, E22i of the operating arms 21, 22 may be curved in the opposite direction to the outer edge portions E21o, E22o, or may be non-curved (straight, angular, etc.) (not shown).

[0078] In addition, the configuration of the clamp sensor 2 has been described as an example in which both operating arms 21, 22 are formed so that the distance L21 between the end 21b of the operating arm 21 and the rotation shaft 30 is shorter than the distance L22 between the end 22b of the operating arm 22 and the rotation shaft 30, but both "operating arms" can also be formed so that the "first distance" in "one operating arm" and the "second distance" in the "other operating arm" are equal (not shown). In addition, the configuration of the clamp sensor 2 has been described as an example in which a biasing member for maintaining both clamp arms 11, 12 in a closed state is provided, but a configuration can also be adopted in which the "pair of clamp arms" is maintained in a closed state by restricting operation of the "pair of operating arms" in a direction approaching each other using an "arm rotation restricting member (rotation restricting member 23 in the clamp sensor 2)" without providing a biasing member.

[0079] In addition, an example has been given of a configuration in which the position of the pivot of the rotation limiting member 23 relative to the operating arm 21, the length of the rotation limiting member 23, and the shape of the rotation limiting member 23 are specified so that in the unlocked state, the rotation limiting member 23 is integrated with the operating arm 21 and becomes like a single rod body, and the rotation limiting member 23 is not present between the operating arms 21, 22. However, a "clamp sensor" can also be configured by specifying the position of the pivot of the "arm rotation limiting member" relative to "one of the operating arms," ​​the length of the "arm rotation limiting member," and the shape of the "arm rotation limiting member," so that in the unlocked state, the "arm rotation limiting member" is lined up with the "one of the operating arms" or the "arm rotation limiting member" protrudes from the "one of the operating arms" (i.e., a state in which the "arm rotation limiting member" is present between both "operating arms" in the unlocked state).

[0080] Furthermore, the configuration of the clamp sensor 2 has been described as an example in which the operating arm 22 and the rotation limiting member 23 are formed so that, when viewed along the axial direction of the rotation shaft 30, the "virtual straight line" passing through the ends 23a, 23b of the rotation limiting member 23 in the "second state (locked state)" is perpendicular (or nearly perpendicular) to the abutment surface F22 against which the end 23b (abutment surface F23) of the rotation limiting member 23 abuts on the operating arm 22. However, the "other operating arm" and "arm rotation limiting member" can also be formed so that the "virtual straight line" and the "abutment surface" intersect at an acute angle (or obtuse angle).

[0081] Also, either one of the magnets M21, M23 constituting the "first member rotation regulating part" can be made of various magnetic bodies (such as iron pieces) that can be attracted by a "permanent magnet", and either one of the magnets M22, M23 constituting the "second member rotation regulating part" can be made of various magnetic bodies (such as iron pieces) that can be attracted by a "permanent magnet". Furthermore, either or both of the "first member rotation regulating part" and the "second member rotation regulating part" can be made of a mechanical positioning structure such as a ball notch mechanism without a "permanent magnet". Also, a configuration that does not include either one of the "first member rotation regulating part" and the "second member rotation regulating part" can be adopted. In addition, a configuration was adopted in which magnet M23 is commonly used (shared) as the magnet that constitutes the "first member rotation regulating portion" and the "second member rotation regulating portion," but a magnet other than magnet M23 or various types of magnetic material (such as a piece of iron) can also be provided in the "second member rotation regulating portion (in this example, rotation regulating member 23)."

[0082] In addition, the configurations of the measuring device 1 and clamp sensor 2 capable of measuring the current value of the current flowing through the clamp object X as the "measured quantity" have been described as examples, but the same configuration as the measuring device 1 and clamp sensor 2 described above can also be adopted in a "measuring device" and "clamp sensor" capable of measuring various electrical parameters other than the current value as the "measured quantity". [Explanation of symbols]

[0083] 1. Measuring equipment 2 Clamp Sensor 3. Measuring device body 10 Sensor section 11,12 Clamp arm 11a,11b,12a,12b End 20 Control section 21,22 Operation arm 21a, 21b, 22a, 22b end 23 Rotation restriction member 23a,23b end 30 Rotating Axis 40 Signal Cable E21o, E21i, E22o, E22i Outer edge F22 Abutted surface F23 Contact surface L1 dashed line L2 double-dashed line L21,L22 distance M21~M23 Magnet W10, W20 width X Clamp Target

Claims

1. A clamp sensor comprising a pair of clamp arms formed in an arc shape and constituting an annular sensor section in a closed state in which tip portions are abutted against each other, and configured so that both clamp arms can be rotated about a rotation axis disposed near base ends of both clamp arms so as to move the tip portions toward and away from each other, a pair of operation arms each extending from the base end of each of the clamp arms and configured to be pivoted about the pivot shaft so as to approach each other, thereby moving the clamp arms to an open state in which the tip ends are spaced apart from each other; an arm rotation restricting member having one end pivotally supported by one of the operating arms, which allows relative rotation of the one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from the closed state to the open state in a first state in which the one operating arm is rotated with respect to the one operating arm so that the other end does not abut against the other operating arm, and which restricts relative rotation of the one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from the closed state to the open state in a second state in which the one operating arm is rotated with respect to the one operating arm so that the other end abuts against the other operating arm, The arm rotation limiting member and the other operating arm are formed such that, when viewed along the axial direction of the rotation shaft, a virtual straight line passing through the one end and the other end of the arm rotation limiting member in the second state is perpendicular or nearly perpendicular to the abutment surface of the other operating arm against which the other end abuts.

2. The arm rotation restricting member and the one of the operating arms are provided with a first member rotation restricting portion that restricts rotation of the arm rotation restricting member in the first state, The clamp sensor of claim 1, wherein the first member rotation restricting portion includes a first permanent magnet arranged on the arm rotation restricting member and on one of the operating arms, and is configured to be able to restrict the rotation of the arm rotation restricting member by the attractive force of both first permanent magnets.

3. The arm rotation restricting member and the other operating arm are provided with a second member rotation restricting portion that restricts rotation of the arm rotation restricting member in the second state, The clamp sensor of claim 2, wherein the second member rotation restricting portion includes a second permanent magnet arranged on the arm rotation restricting member and the other operating arm, and is configured to be able to restrict the rotation of the arm rotation restricting member by the attractive force of both second permanent magnets.

4. The arm rotation restricting member and the other operating arm are provided with a second member rotation restricting portion that restricts rotation of the arm rotation restricting member in the second state, The clamp sensor of claim 1, wherein the second member rotation restricting portion includes a second permanent magnet arranged on the arm rotation restricting member and the other operating arm, and is configured to restrict the rotation of the arm rotation restricting member by the attractive force of both second permanent magnets.

5. A clamp sensor comprising a pair of clamp arms formed in an arc shape and constituting an annular sensor section in a closed state in which tip portions are abutted against each other, and configured so that both clamp arms can be rotated about a rotation axis disposed near base ends of both clamp arms so as to move the tip portions toward and away from each other, a pair of operation arms each extending from the base end of each of the clamp arms and configured to be pivoted about the pivot shaft so as to approach each other, thereby moving the clamp arms to an open state in which the tip ends are spaced apart from each other; an arm rotation restricting member having one end pivotally supported by one of the operating arms, which allows relative rotation of the one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from the closed state to the open state in a first state in which the one operating arm is rotated with respect to the one operating arm so that the other end does not abut against the other operating arm, and which restricts relative rotation of the one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from the closed state to the open state in a second state in which the one operating arm is rotated with respect to the one operating arm so that the other end abuts against the other operating arm, a first member rotation restricting portion that restricts rotation of the arm rotation restricting member in the first state is provided on the arm rotation restricting member and the one of the operating arms; The first member rotation restricting portion includes a first permanent magnet disposed on the arm rotation restricting member and one of the operating arms, and is configured to be able to restrict the rotation of the arm rotation restricting member by the attractive force of both first permanent magnets.

6. The arm rotation restricting member and the other operating arm are provided with a second member rotation restricting portion that restricts rotation of the arm rotation restricting member in the second state, The clamp sensor of claim 5, wherein the second member rotation restricting portion includes a second permanent magnet arranged on the arm rotation restricting member and the other operating arm, and is configured to be able to restrict the rotation of the arm rotation restricting member by the attractive force of both second permanent magnets.

7. A clamp sensor comprising a pair of clamp arms formed in an arc shape and constituting an annular sensor section in a closed state in which tip portions are abutted against each other, and configured so that both clamp arms can be rotated about a rotation axis disposed near base ends of both clamp arms so as to move the tip portions toward and away from each other, a pair of operation arms each extending from the base end of each of the clamp arms and configured to be pivoted about the pivot shaft so as to approach each other, thereby moving the clamp arms to an open state in which the tip ends are spaced apart from each other; an arm rotation restricting member having one end pivotally supported by one of the operating arms, which allows relative rotation of the one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from the closed state to the open state in a first state in which the one operating arm is rotated with respect to the one operating arm so that the other end does not abut against the other operating arm, and which restricts relative rotation of the one operating arm with respect to the other operating arm in a direction that transitions both clamp arms from the closed state to the open state in a second state in which the one operating arm is rotated with respect to the one operating arm so that the other end abuts against the other operating arm, a second member rotation restricting portion that restricts rotation of the arm rotation restricting member in the second state is provided on the arm rotation restricting member and the other operating arm; The second member rotation regulating portion includes a second permanent magnet arranged on the arm rotation regulating member and the other operating arm, and is configured to be able to regulate the rotation of the arm rotation regulating member by the adhesive force of both second permanent magnets.

8. both operating arms are formed such that a first distance between an end of one operating arm opposite to the clamp arm side and the pivot shaft is shorter than a second distance between an end of the other operating arm opposite to the clamp arm side and the pivot shaft, A clamp sensor as described in any one of claims 1 to 7, wherein the arm rotation restricting member is pivotally supported on one of the operating arms so that in the first state, the other end is located at the end of the one of the operating arms opposite the clamp arm side.

9. A clamp sensor according to any one of claims 1 to 8, A measuring device comprising a measuring unit that measures a measurable quantity of a clamped object clamped by the clamp sensor.

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