Microswitch and pressure-activated switch

Abstract

To provide a manually reset microswitch and a pressure-activated switch that operate reliably.SOLUTION: A microswitch 1 includes a lever 16 that rotates around a rotation shaft 15 in a forward direction a and a backward direction b, a movable contact 42 that performs a reversing operation in association with the rotation of the lever 16, a fixed contact 41, and a reset member 70. The range of rotation of the lever 16 includes a first reversal position where a reversing operation occurs when the lever 16 passes in the forward direction a, and a second reversal position where a reversing operation occurs when the lever 16 passes in the backward direction b. The reset member 70 is displaceable between a restricting position P1 that restricts the rotation of the lever 16 toward the backward direction b after passing the first reversal position in the forward direction a between the first reversal position and the second reversal position, and a reset position P2 that rotates the lever 16 toward the backward direction b until it passes the second reversal position.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a microswitch and a pressure responsive switch. [Background technology]

[0002] Conventionally, a microswitch having a manual reset mechanism is known (see, for example, Patent Document 1). In the microswitch (thermal relay) described in Patent Document 1, as shown in FIG. 1 of Patent Document 1, a movable contact (5) is provided between a NO contact (9) and an NC contact (10) as fixed contacts, and the movable contact (5) is supported by a movable contact plate (14). The movable contact plate (14) is connected to an adjustment plate (12) via a reversing spring (13). An adjustment screw (11) is disposed near the adjustment plate (12) and can press the adjustment plate (12) in the plate thickness direction by tightening. In this microswitch, the adjustment plate (12) is displaced by adjusting the tightening amount of the adjustment screw (11), and the reset position of the movable contact plate (14) is adjusted by adjusting the reversing force of the reversing spring (13) generated by the displacement. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 53-149869 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned microswitch, the reset position is determined depending on the balance between the biasing force of the adjusting plate (12) and the reversing force of the reversing spring (13), so it is possible that the state of the movable contact (5) will not be determined depending on the dimensional variation of the adjusting plate (12) and the dimensional variation of the reversing spring (13). In addition, it is possible that the tightening amount of the adjusting plate (12) will vary due to the influence of vibrations acting on the microswitch. This can result in unintended auto-resetting, or conversely, inability to reset, making it difficult to operate the manual reset mechanism accurately.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a manually reset microswitch and a pressure responsive switch which have high operational reliability. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the object, the microswitch of the present invention is a microswitch comprising a lever that rotates in a forward and backward directions around a rotation axis, a movable contact that performs a reversing motion in association with the rotation of the lever, a pair of fixed contacts to which the movable contact can be conductive, and a determining portion that determines the position of the rotation direction of the lever, wherein the rotation range of the lever includes a first reversal position at which the reversing motion occurs when the lever passes in the forward direction, and a second reversal position at which the reversing motion occurs when the lever passes in the backward direction, and the determining portion is displaceable between a restricting position that restricts the rotation of the lever toward the backward direction between the first reversal position and the second reversal position after passing the first reversal position in the forward direction, and a reset position at which the lever toward the backward direction is rotated until it passes the second reversal position.

[0007] According to the present invention, the position of the lever in the rotation direction can be determined by displacing the position of the determining portion, and the position of the movable contact can be determined according to the position of the lever in the rotation direction. Therefore, the restricting position can be accurately determined according to the position of the determining portion, and the state in which the lever rotation in the retracting direction from the restricting position is restricted can be accurately maintained, and the reversing operation of the movable contact can be accurately controlled. This is different from the structure of the conventional microswitch shown in Patent Document 1, in which the reset mechanism is operated depending on the balance of forces. That is, this configuration is different from the structure in which the state of the movable contact (5) is not determined due to dimensional variations in the adjustment plate (12) and the reversing spring (13), and the tightening amount of the adjustment plate (12) is deviated due to the influence of vibration, etc., and the reset mechanism can be accurately operated by controlling the position of the determining portion. Therefore, according to this configuration, unintended auto-resetting can be prevented, and the reset operation can be reliably performed when necessary. Therefore, a manual reset type microswitch with high operational reliability can be provided.

[0008] In addition, it is preferable that the determining portion includes a reset plate that determines the position of the lever in the rotation direction, and a reset shaft that moves the reset plate forward and backward in the axial direction, the reset position being located on one side in the axial direction, and the restricting position being located on the other side in the axial direction. With this configuration, the reset plate can be easily displaced between the restricting position and the reset position by moving the reset shaft forward and backward in the axial direction.

[0009] It is also preferable to provide a biasing means for biasing the reset shaft toward the other axial direction, the defining portion being displaceable to the reset position by pressing the reset shaft toward one axial direction against the biasing force of the biasing means, and the defining portion being located at the restricted position when the reset shaft is not pressed in. With this configuration, the reset plate is displaced to the reset position by pressing the reset shaft toward one axial direction, and the reset plate is automatically displaced to the restricted position by the biasing force of the biasing means by ceasing to press the reset shaft, and is located at the restricted position.

[0010] Furthermore, the pressure responsive switch of the present invention is characterized in that it is equipped with any one of the microswitches described above. With this configuration, the pressure responsive switch can be configured using a manually reset type microswitch with high operational reliability. Effect of the Invention

[0011] According to the present invention, a manually reset type microswitch having high operational reliability can be provided. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a bottom view of a pressure responsive switch equipped with a microswitch according to an embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] 3 is a cross-sectional view taken along line AA in FIG. 2 , showing the microswitch when the manual reset mechanism is released. [Diagram 5] 3 is a cross-sectional view taken along line AA in FIG. 2, showing a microswitch that indicates a waiting state for the manual reset mechanism to be released. [Figure 6] Bottom view of the microswitch. [Figure 7] 5A to 5C are schematic diagrams showing the operation of a microswitch having an auto-reset mechanism. [Figure 8] FIG. 13 is a schematic diagram showing the operation of a microswitch equipped with a manual reset mechanism until pressure is released. [Figure 9] FIG. 13 is a schematic diagram showing the operation of a microswitch equipped with a manual reset mechanism during and after a pressure drop. [Figure 10] 5A to 5C are schematic diagrams showing the adjustment operation of the manual reset mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An embodiment of the present invention will be described below. The microswitch 1 according to this embodiment is mounted on a pressure-responsive switch 100 that detects pressure changes and temperature changes of a fluid, for example, and detects pressure changes and temperature changes of a fluid, for example, a working medium of a refrigeration cycle, an automobile, an actuator for various controls, etc. In the following description, the axial direction of the operating shaft 20 and the reset shaft 71 described later is indicated by an arrow Z in the drawings and is described as the "upper side Z". One side of the upper side Z is described as the "upper side Z1", and the other side is described as the "lower side Z2". In addition, horizontal directions intersecting the upper side Z are indicated by an arrow X and an arrow Y and are described as the "front-rear direction X" and the "left-right direction Y", respectively. One side of the front-rear direction X is described as the "front side X1", the other side is described as the "rear side X2", one side of the left-right direction Y is described as the "left side Y1", and the other side is described as the "right side Y2". The definitions of these directions are given merely for the convenience of explanation, and do not necessarily correspond to the directions in the actual state of use of the microswitch 1, and are not intended to limit the directions in the actual state of use of the microswitch 1.

[0014] As shown in FIG. 1, the pressure responsive switch 100 includes a case 110 having a generally rectangular shape. The case 110 includes a C-shaped main body frame 111 that opens to the lower side Z2, and a cover (not shown) that closes the opening of the main body frame 111, and accommodates various components such as a microswitch 1 (described later) inside. The main body frame 111 is formed by bending a metal plate material, and includes a front wall portion 112, a top wall portion 113, and a rear wall portion 114. A pair of elements 115 and a pair of joint tubes 116 that are respectively connected to the pair of elements 115 are connected to the rear wall portion 114 of the case 110. The element 115 includes a sensitive member such as a bellows or a diaphragm (not shown) inside. The sensitive member is deformed or displaced in the front-rear direction X in response to a pressure change of the pressure fluid introduced through the joint tube 116.

[0015] A pair of left and right transmission mechanisms 117 and a pair of left and right switch components 118 are housed inside the case 110. The transmission mechanism 117 includes a reinforcing plate 119 formed into a C-shape that opens to the upper side Z1 by bending a metal plate material, and a transmission member 120 is housed inside the reinforcing plate 119. An example of the transmission member 120 is an actuation plate 121, which receives a force that causes the above-mentioned sensitive member to deform or displace as an external force, rotates around a rotation shaft 122, and converts the external force into an operating force, and transmits the operating force to a pressing arm 17 and a lever 16 (a reaction member) described later. The switch component 118 is configured with a plurality of contacts 40 described later, and changes the conductive state of the contacts 40 upon receiving the above-mentioned operating force. A pair of switch components 118 are provided adjacent to each other in the left-right direction Y, and constitute a dual-type microswitch 1. The microswitch 1 is configured with a manual reset mechanism 2, which will be described later. By operating a reset button 76 in the manual reset mechanism 2, the contacts 40, which are in a predetermined conductive state, can be manually switched to a different conductive state.

[0016] FIG. 2 is a perspective view of the microswitch 1, and FIG. 3 is a plan view of the microswitch 1. In FIG. 2, a reset shaft 71 and a reset plate 72, which constitute a manual reset mechanism 2, are omitted. The microswitch 1 includes a box portion 10. The box portion 10 is formed, for example, of a resin material in a substantially cubic shape, and an accommodation space 11 for accommodating various components is formed inside the box portion 10. A connection portion 13 that protrudes to the rear side X2 is formed on a rear wall 12 of the box portion 10. The connection portion 13 is formed in a plate shape extending in the vertical direction Z, and is fixed to the case 110 of the pressure-responsive switch 100 described above. A rectangular box-shaped fixing member 14 is attached to the upper wall of the box portion 10. In this embodiment, a pair of fixing members 14 are attached side by side in the left-right direction Y. A rotating shaft 15 extending in the left-right direction Y is fixed to the side wall of each fixed member 14, and a lever 16 is attached to the rotating shaft 15 so as to be rotatable around the shaft. That is, a pair of levers 16 are provided. In this embodiment, "rotation" means rotation in both forward and reverse directions around the rotating shaft 15 within a predetermined angle range.

[0017] The lever 16 is an actuating fitting made of a metal material and formed into a plate shape, extends from the pivot shaft 15 to the front side X1, and is provided so as to be rotatable in a forward direction a and a backward direction b about the pivot shaft 15. In the initial state shown in FIG. 2, the lever 16 is biased in the backward direction b by a biasing means (not shown), and is inclined so as to be located on the upper side Z1 as it moves from the rear end supported by the pivot shaft 15 toward the front end. The lever 16 rotates in the forward direction a about the pivot shaft 15 by receiving an external force. An example of the external force is a force generated in response to a pressure change of the refrigerant in the above-mentioned refrigeration cycle. Such a force is applied to a sensitive member (not shown) mounted on the pressure switch, and is transmitted to the lever 16 via a pressing arm 17 shown in FIG. 3. The pressing arm 17 is formed into a substantially L-shaped shape in a plan view by bending a metal plate material or the like.

[0018] The tip of the pressing arm 17 is disposed on the upper side Z1 of the front end of the lever 16 other than the part on the inner side in the left-right direction Y, and is displaced to the lower side Z2 in response to the force applied to the sensitive member, causing the lever 16 to rotate in the forward direction a about the rotation shaft 15. A receiving portion 18 is formed on the plate surface of the lever 16. As shown in FIG. 4, the receiving portion 18 is formed by protruding a middle part of the plate surface of the lever 16 in the front-rear direction X to the upper side Z1, and has a V-shaped cross-section surface that opens to the lower side Z2. An operating shaft 20 whose axis extends in the up-down direction Z is supported by the receiving portion 18. The operating shaft 20 is an axial member that converts the rotational motion of the lever 16 into forward and backward motion in the up-down direction Z.

[0019] The actuating shaft 20 is connected to the box part 10 so as to be movable in the vertical direction Z in a state where it is inserted through a through hole 19 penetrating the upper wall of the box part 10 in the vertical direction Z. The upper end of the actuating shaft 20 constitutes a pressed part 21 pressed by the lever 16. In this embodiment, the pressed part 21 is in sliding contact with the V-shaped inner surface of the receiving part 18 of the lever 16 and is pressed to the lower side Z2. Meanwhile, the lower end of the actuating shaft 20 constitutes an engaging part 22 that engages with a switching means 30 described later. The switching means 30 is configured to switch the conductive state of a contact 40 arranged in the accommodation space 11, and includes a movable piece 31 that engages with the engaging part 22 of the actuating shaft 20, a snap piece 32 that abuts against the front end side of the movable piece 31, and a conductive piece 33 having a movable contact 42 described later that is biased by the snap piece 32 to the upper side Z1 or the lower side Z2.

[0020] The snap piece 32 biases the movable contact 42 to the upper side Z1 or the lower side Z2 depending on the position of the engagement portion 22 on the operating shaft 20. Specifically, in the above-mentioned initial state in which the pressing arm 17 does not press the lever 16, the snap piece 32 biases the movable contact 42 to the lower side Z2. Then, as the pressing arm 17 presses the lever 16, the operating shaft 20 descends, and the engagement portion 22 moves to the lower side Z2, the snap piece 32 gradually deforms while maintaining the biasing direction to the lower side Z2. Then, when the engagement portion 22 of the operating shaft 20 moves to the lower side Z2 beyond a lower limit position (not shown), the snap piece 32 can no longer maintain the biasing direction to the lower side Z2, so it reverses to the upper side Z1 and biases the movable contact 42 to the upper side Z1 as shown in FIG. 5. Then, from this state, the engaging portion 22 of the operating shaft 20 rises, and as the engaging portion 22 moves to the upper side Z1, the snap piece 32 gradually deforms while maintaining the biasing direction to the upper side Z1. Then, when the engaging portion 22 of the operating shaft 20 moves to the upper side Z1 beyond an upper limit position (not shown) (a position on the Z1 side above the above-mentioned lower limit position), the snap piece 32 can no longer maintain the biasing direction to the upper side Z1, and reverses to the lower side Z2, biasing the movable contact 42 to the lower side Z2 as shown in FIG. 4.

[0021] The contact 40 is a conductive member made of a conductive material, and includes a pair of fixed contacts 41 fixed in the accommodation space 11, and a movable contact 42 disposed between the pair of fixed contacts 41. The pair of fixed contacts 41 is composed of a first fixed contact 41A and a second fixed contact 41B. The first fixed contact 41A is fixed to the inner wall of the box part 10 while facing the upper side Z1. The second fixed contact 41B is fixed to the inner wall of the box part 10 while facing the lower side Z2 and disposed above the first fixed contact 41A. The movable contact 42 is fixed to the front end of the conductive piece 33, and displaces to the upper side Z1 or the lower side Z2, which is the biasing direction of the snap piece 32, to come into contact with the first fixed contact 41A or the second fixed contact 41B, and is capable of being electrically connected to the first fixed contact 41A or the second fixed contact 41B.

[0022] As described above, the movable contact 42 can be inverted to switch the conductive destination by changing the biasing direction by reversing the up-down direction Z of the snap piece 32. Specifically, the movable contact 42 can be switched between a first conductive state ("operating-fixed A: ON" in the tables of FIGS. 7 to 9) in which the movable contact 42 is displaced to the lower side Z2 and conductive to the first fixed contact 41A, and a second conductive state ("operating-fixed A: OFF" in the tables of FIGS. 7 to 9) in which the movable contact 42 is displaced to the upper side Z1 and conductive to the second fixed contact 41B. In the following description, the "first conductive state" may be referred to as the first conductive state (operating-fixed A: ON), and the "second conductive state" may be referred to as the second conductive state (operating-fixed A: OFF).

[0023] In this embodiment, in the above-mentioned initial state in which the pressing arm 17 does not press the lever 16, the snap piece 32 biases the movable contact 42 to the lower side Z2, and the movable contact 42 is in the first conductive state. The contact 40 configured in this manner is connected to a terminal 50. The terminal 50 is a member to which the above-mentioned first fixed contact 41A, second fixed contact 41B, and movable contact 42 are connected in a one-to-one relationship, and is formed in a plate shape using a conductive material. In this embodiment, since a pair of levers 16 is provided in the box portion 10, a pair of operating shafts 20, switching means 30, and contacts 40 corresponding to each lever 16 is also provided. As a result, a total of six contacts 40 are provided. Therefore, as shown in FIG. 6, a total of six terminals 50 are provided. The terminal 50 is inserted into an insertion hole 10a formed in the bottom wall of the box portion 10, and a mounting portion 51 at the lower end to which an electric wire (not shown) is connected is bent by a fastening member 123 (see FIG. 1), and the mounting portion 51 is fixed along the bottom wall of the box portion 10.

[0024] Here, in this embodiment, the microswitch 1 has a snap piece 32. Therefore, in the case where the microswitch does not have a mechanism related to the manual reset mechanism 2 (described later), that is, in the case of a so-called auto-reset type microswitch, the microswitch operates as follows with the rotation of the lever 16. That is, as shown in "Initial (0 MPa)" in the table of FIG. 7, the lever 16 in the initial state rotates in the moving direction a due to the increase in the pressure of the fluid as shown in "Increasing Pressure" in the table of FIG. 7, and the operating shaft 20 descends accordingly. When the engaging portion 22 moves to the lower side Z2 beyond the above-mentioned lower limit position where the snap piece 32 cannot maintain the biasing direction of the lower side Z2, the snap piece 32 reverses, and a reversal operation occurs in the movable contact 42, and the conductive state is switched from the first conductive state (operating-fixed A: ON) to the second conductive state (operating-fixed A: OFF). The state of the lever 16 when this reversal operation occurs is shown in "Above Rising Operation Value" in the table of FIG. 7. The above-mentioned auto-reset type microswitch is sometimes called an automatic return type microswitch.

[0025] In this embodiment, the position where the reversal action occurs when the lever 16 passes in the travel direction a is the first reversal position (referred to as the rising point in Figs. 7 to 9) in the position of the rotation direction of the lever 16. According to this configuration, for example, by mounting the microswitch 1 on a pressure switch, a high-pressure cutoff switch that switches the conduction state from the first conduction state to the second conduction state when an abnormal high pressure occurs can be configured. In the case of an auto-reset type (or automatic return type) microswitch as described above, as shown in "During Pressure Decreasing" in the table of Fig. 7, after the above-mentioned reversal action (i.e., after cutoff), the lever 16 rotates in the retreat direction b due to a decrease in the pressure of the fluid, and the operating shaft 20 rises, and when returning to the first conduction state before the switching ("initial (0 MPa)" shown in Fig. 7), when the engaging portion 22 moves to the upper side Z1 beyond the above-mentioned upper limit position where the snap piece 32 cannot maintain the biasing direction of the upper side Z1, the snap piece 32 reverses, and the movable contact 42 undergoes a reversal action accordingly. This causes the conduction state to switch from the second conduction state to the first conduction state.

[0026] In this embodiment, the position where the reversal occurs when the lever 16 passes in the backward direction b is the second reversal position (referred to as the down point in Figs. 7 to 9) in the position of the rotation direction of the lever 16. According to this configuration, the rotation range of the lever 16 includes the first reversal position (upward point) where the reversal occurs when the lever 16 passes in the forward direction a, and the second reversal position (downward point) where the reversal occurs when the lever 16 passes in the backward direction b. In this manner, the microswitch 1 of this embodiment is configured as a switch in which the first reversal position, which is a set value as a trigger for performing high pressure cutoff, and the second reversal position, which is a set value as a trigger for returning to the original state, are different positions. In the following description, the "first reversal position" may be referred to as the first reversal position (upward point), and the "second reversal position" may be referred to as the second reversal position (downward point).

[0027] The microswitch 1 configured as above includes a manual reset mechanism 2. The manual reset mechanism 2 is used, for example, when the above-mentioned high voltage cutoff occurs, to maintain the second conductive state for the purpose of a subsequent maintenance work by an operator, and to release the maintenance of the second conductive state and return to the first conductive state after the maintenance work is completed. As shown in FIG. 4, the manual reset mechanism 2 includes a mounting hole 60 formed through the box part 10. The mounting hole 60 includes a shaft support part 61 extending in the up-down direction Z and opening on the upper wall of the box part 10, a spring receiving part 62 continuing from the lower end of the shaft support part 61, having an inner diameter larger than that of the shaft support part 61, and extending to the lower side Z2, and a button support part 63 continuing from the lower end of the spring receiving part 62, having an inner diameter larger than that of the spring receiving part 62, and opening on the lower wall of the box part 10.

[0028] A reset member 70 (defining portion) that defines the position of the lever 16 in the rotation direction is inserted into the mounting hole 60. The reset member 70 includes a cylindrical reset shaft 71 that extends in the vertical direction Z. A threaded portion (not shown) is formed on the upper end side of the reset shaft 71, and a reset plate 72 that protrudes to the rear side X2 is screw-engaged with the threaded portion. As shown in FIG. 3, the reset plate 72 includes a substantially rectangular plate-shaped main body portion 72a with four corners cut out, and a pressing portion 72b that protrudes outward in the horizontal direction Y from an outer edge of the main body portion 72a in the horizontal direction Y. The lower surface of the pressing portion 72b is provided so as to be able to press the upper surface of the front end portion of the lever 16 at the inner side in the horizontal direction Y. When the reset plate 72 is displaced in the vertical direction Z in accordance with the displacement of the reset shaft 71 in the vertical direction Z, the pressing portion 72b presses the lever 16 downward Z2, thereby defining the position of the lever 16 in the rotation direction. That is, the reset shaft 71 moves the reset plate 72 back and forth in the vertical direction Z, and this back and forth movement causes the reset plate 72 to determine the position of the lever 16 in the rotation direction.

[0029] The reset plate 72 can be displaced in the vertical direction Z relative to the reset shaft 71 by screwing the screw-engaged portion. A first E-ring 73 is attached to the lower side Z2 of the reset plate 72 (between the reset plate 72 and the opening of the mounting hole 60 on the reset plate 72 side). The first E-ring 73 is provided so as to protrude radially outward from the reset shaft 71, and its lower surface can abut against the upper wall of the box part 10. This restricts the reset shaft 71 from being displaced downward Z2 from the position where the lower surface of the first E-ring 73 abuts against the upper wall of the box part 10, as shown in FIG. 5. That is, the first E-ring 73 defines the lower end position L of the reset shaft 71. On the other hand, a second E-ring 74 is attached to the lower end side of the reset shaft 71. The second E-ring 74 is provided so as to protrude radially outward from the reset shaft 71, and its upper surface can abut against a step at the boundary between the spring receiving part 62 and the button support part 63. 4, the reset shaft 71 is restricted from being displaced upward Z1 from the position where the upper surface of the second E-ring 74 abuts against the step at the boundary between the spring receiving portion 62 and the button support portion 63. In other words, the second E-ring 74 defines the upper end position H of the reset shaft 71.

[0030] A reset spring 75 (biasing means) is housed between the second E-ring 74 and the upper end of the spring receiving portion 62. That is, the second E-ring 74 also functions as a spring receiving portion. The reset spring 75 biases the reset shaft 71 toward the lower side Z2 via the second E-ring 74. A reset button 76 is attached to the lower end of the reset shaft 71. The reset button 76 is an operation portion for an operator to displace the reset shaft 71 in the vertical direction Z, and is formed in an elliptical shape when viewed from the bottom as shown in FIG. 6. The reset button 76 is supported by the button support portion 63, and can be pushed toward the upper side Z1 up to a step portion at the boundary with the spring receiving portion 62 in the button support portion 63. By pushing the reset button 76, the reset shaft 71 is displaced toward the upper side Z1 against the biasing force of the reset spring 75. The biasing force of the reset spring 75 and the amount of depression of the reset button 76 can be adjusted as appropriate, but in this embodiment, when the reset button 76 is pressed down to its limit, the reset shaft 71 is displaced to the upper end position H. On the other hand, when the reset button 76 is not pressed down, the biasing force of the reset spring 75 automatically positions the reset shaft 71 at the lower end position L.

[0031] Next, the operation of the microswitch 1 will be described. FIG. 8 is a schematic diagram showing the operation of the microswitch 1 equipped with the manual reset mechanism 2 up to the pressure drop. FIG. 9 is a schematic diagram showing the operation of the microswitch 1 equipped with the manual reset mechanism 2 after "pressure drop". In FIG. 8 and 9 (FIG. 10), the rotating shaft 15, the lever 16, and the reset plate 72 are shown in schematic shapes rather than their actual shapes to prevent the diagram from becoming complicated. First, in a state where the reset button 76 is not operated, as shown in "initial (0 MPa)" in the table of FIG. 8, the lever 16 is in contact with the reset plate 72 and is positioned between the first reversal position and the second reversal position. In this state, the movable contact 42 is conductive to the first fixed contact 41A and is in the first conductive state (operated-fixed A: ON).

[0032] From this state, as shown in "Pressure rising" in the table of FIG. 8, the pressure of the fluid rises, and if the pressure of the fluid rises further from this state and becomes abnormally high pressure that exceeds the assumption, as shown in "Above rising actuation value" in the table of FIG. 8, the lever 16 is displaced in the forward direction a and exceeds the first reversal position (rising point). This causes a reversal operation of the movable contact 42, and the movable contact 42 is displaced to the upper side Z1 and conducts with the second fixed contact 41B, switching to the second conduction state (operating-fixed A: OFF). Then, from this state, when the pressure of the fluid drops, as shown in "Pressure falling" in the table of FIG. 8, the lever 16 rotates in the backward direction b. Then, this rotation is restricted by the lever 16 abutting against the reset plate 72, as shown in "Below falling actuation value = waiting to be released" in the table of FIG. 9.

[0033] A position where the rotation of the lever 16, which passes through the first reversal position (upward point) in the forward direction a and then moves toward the backward direction b, is restricted between the first reversal position (upward point) and the second reversal position (downward point) is defined as a "restriction position P1". In this embodiment, as shown in FIG. 5, the contact position between the reset plate 72 and the lever 16 when the reset shaft 71 is located at the lower end position L is the restriction position P1. As described above, the microswitch 1 of the present invention is configured as a switch in which the first reversal position (upward point), which is a set value as a trigger for executing high pressure cutoff, and the second reversal position (downward point), which is a set value as a trigger for returning to the original state, are different positions. For this reason, when the rotation of the lever 16 in the backward direction b is restricted at the restricting position P1, the position of the rotation direction of the lever 16 is between the first reversal position (ascending point) and the second reversal position (descending point), similar to the rotation direction position shown as "initial 0 MPa" in the table of Figure 8, but no reversal operation of the movable contact 42 occurs, and the second conductive state is maintained.

[0034] As a result, if a design is made such that an alarm is issued in the second conductive state, even if some abnormality occurs and then the abnormality is automatically corrected, the operator can be notified of the occurrence of the abnormality. This is useful because the operator can perform maintenance work, etc. After the maintenance work, etc. is completed, in order to reset the movable contact 42 by returning it from the second conductive state to the first conductive state, it is necessary to displace the reset plate 72 to a position where the lever 16 can rotate in the backward direction b and pass the second reversal position (downward point). Therefore, as shown in FIG. 4, the reset button 76 is pushed upward Z1, and the reset shaft 71 and the reset plate 72 are displaced upward Z1. As a result, as shown in "Released (button pushed)" in the table of FIG. 9, the lever 16 can rotate in the backward direction b and pass the second reversal position in the same direction. At this time, a reversal operation occurs, and the movable contact 42 switches from the second conductive state (moving-fixed A: OFF) to the first conductive state (moving-fixed A: ON).

[0035] The position where the lever 16 moving in the backward direction b is rotated until it passes through the second reversal position (downward point) is defined as the "reset position P2". In this embodiment, as shown in FIG. 4, the contact position between the reset plate 72 and the lever 16 when the reset shaft 71 is located at the upper end position H is the reset position P2. With this configuration, in the vertical direction Z of the reset shaft 71, the reset position P2 is located on the upper side Z1 (one axial side), and the restriction position P1 is located on the lower side Z2 (the other axial side), and the reset plate 72 (reset member 70) is supported so as to be displaceable between the reset position P2 and the restriction position P1. Finally, when the reset button 76 is released from being pressed, the reset shaft 71 is automatically displaced to the lower side Z2 by the biasing force of the reset spring 75, and the reset plate 72 returns to its original position (restriction position P1), completing the operation of the manual reset mechanism 2.

[0036] As described above, in this embodiment, the contact position between the reset plate 72 and the lever 16 when the reset shaft 71 is located at the lower end position L is the restricting position P1, and the contact position between the reset plate 72 and the lever 16 when the reset shaft 71 is located at the upper end position H is the reset position P2. However, this is merely an example, and any position that fits the definition of the restricting position P1 and can be moved to the reset position P2 may be the restricting position P1. Also, any position that fits the definition of the reset position P2 and can be moved to the restricting position P1 may be the reset position P2. Next, the adjustment operation of the manual reset mechanism 2 will be described. FIG. 10 is a schematic diagram showing the adjustment operation of the manual reset mechanism 2. As described above, in the microswitch 1 of this embodiment, when the movable contact 42 changes from the first conductive state to the second conductive state, the second conductive state is maintained. This is particularly important in order to notify an operator of an abnormality when the microswitch 1 detects an abnormality and changes from the first conductive state to the second conductive state. In other words, it is necessary to change from the second conductive state to the first conductive state only when the reset button 76 is pressed. Therefore, it is necessary to ensure that the lever 16 is accurately positioned at the regulating position P1 and that this state is maintained when the reset button 76 is not operated, and that the lever 16 moving in the backward direction b reliably passes through the reset position P2 when the reset button 76 is operated, and for this purpose it is necessary to accurately determine the first reversal position (ascending point) and the second reversal position (descending point).

[0037] Therefore, the manual reset mechanism 2 is adjusted. First, as shown in "Initial" and "Forced Operation" in the table of FIG. 10, the lever 16 in the initial state is forcibly rotated in the forward direction a by the reset plate 72 to a position where the first conductive state changes to the second conductive state, that is, the first reversal position (ascending point). At this time, as described above, it is useful to move the reset plate 72 downward Z2 with respect to the reset shaft 71 by screwing the reset plate 72, because this allows fine adjustment of the position of the reset plate 72. Next, as shown in "Looking for the descending point" in the table of FIG. 10, the lever 16 is rotated in the backward direction b by the reset plate 72 to a position where the second conductive state changes to the first conductive state, that is, the second reversal position (descending point).

[0038] At this time, it is useful to move the reset plate 72 to the upper side Z1 with respect to the reset shaft 71 by screwing the reset plate 72, since this allows fine adjustment of the position of the reset plate 72. These operations allow the first reversal position (ascending point) and the second reversal position (descending point) to be accurately determined. This allows the reset position P2 to be accurately known, and the regulating position P1 to be accurately determined. Finally, as shown in "Adjustment" in the table of FIG. 10, the lever 16 is rotated in the traveling direction a by the reset plate 72, and the lever 16 is positioned between the first reversal position (ascending point) and the second reversal position (descending point), and this position is set as the regulating position P1. This completes the operation of adjusting the manual reset mechanism 2.

[0039] It is also possible to determine the restriction position P1 by positioning the lever 16 at the second reversal position (downward point) and then at the first reversal position (upward point), and then performing the final adjustment toward the second reversal position (downward point) side as described above, in the opposite manner to the above adjustment. However, according to this embodiment, by performing the final adjustment from the second reversal position (downward point) toward the first reversal position (upward point), it is possible to reliably position the lever 16 closer to the first reversal position (upward point) than the second reversal position (downward point), and therefore it is possible to more reliably prevent unintended auto-reset.

[0040] According to the above-described embodiment, the position of the lever 16 in the rotation direction can be determined by displacing the position of the reset member 70 (determining portion), and the position of the movable contact 42 can be determined according to the position of the lever 16 in the rotation direction. Therefore, the restricting position P1 can be accurately determined according to the position of the reset member 70, and the state in which the rotation of the lever 16 in the retreating direction b from the restricting position P1 can be accurately maintained, and the reversing operation of the movable contact 42 can be accurately controlled. This is different from the structure of the conventional microswitch shown in Patent Document 1, in which the reset mechanism is operated depending on the balance of forces. That is, unlike the structure in which the state of the movable contact (5) is not determined due to the dimensional variation of the adjustment plate (12) and the reversing spring (13), and the tightening amount of the adjustment plate (12) is deviated due to the influence of vibration, etc., this configuration can accurately operate the manual reset mechanism 2 (reset mechanism) by controlling the position of the reset member 70. Therefore, according to this configuration, unintended auto-reset can be prevented, and the reset operation can be reliably performed when necessary. Therefore, it is possible to provide a microswitch 1 (manual reset type microswitch) with high operational reliability.

[0041] According to the present embodiment, the reset member 70 includes the reset shaft 71 and the reset plate 72. Therefore, by moving the reset shaft 71 back and forth in the vertical direction Z (axial direction), the reset plate 72 can be easily displaced between the restriction position P1 and the reset position P2.

[0042] Furthermore, according to this embodiment, by pressing the reset shaft 71 upward Z1, the reset plate 72 is displaced to the reset position P2, and by ceasing to press the reset shaft 71, the reset plate 72 is automatically displaced to the regulating position P1 by the biasing force of the reset spring 75 (biasing means), and can be positioned at the regulating position P1.

[0043] Moreover, according to this embodiment, the pressure responsive switch 100 can be configured using the microswitch 1 (manual reset type microswitch) that has high operational reliability.

[0044] The above-described embodiments merely show typical forms of the present invention, and the present invention is not limited to these. In other words, various modifications can be made without departing from the gist of the present invention. As long as the configuration of the microswitch 1 of the present invention is included in such modifications, they are of course included in the scope of the present invention. For example, in the description of this embodiment, the microswitch 1 and the manual reset mechanism 2 are described as being used when detecting abnormally high pressure, but conversely, the microswitch 1 and the manual reset mechanism 2 can also be used when detecting abnormally low pressure. In addition, in the initial state, the lever 16 is inclined so as to be positioned on the upper side Z1 as it moves from the rear end supported by the rotating shaft 15 to the front end. Conversely, the state after rotation in this embodiment may be set as the initial state of the lever 16, the retracting direction b in this embodiment may be set as the advancing direction a, and the operating direction of the operating shaft 20, the switching means 30, and the manual reset mechanism 2 may be adjusted accordingly to construct the microswitch 1 and the manual reset mechanism 2.

[0045] Moreover, the microswitch 1 and the manual reset mechanism 2 can be mounted on various switches other than pressure switches in which the lever 16 rotates upon receiving some external force. For example, although the pressure responsive switch 100 of this embodiment has been described mainly as a pressure switch, the pressure responsive switch 100 can also be used as a temperature switch. That is, in this embodiment, the pressure responsive switch 100 is used as a pressure switch that detects pressure changes by introducing a fluid to be detected (here, a refrigerant circulating in a refrigeration cycle) through the joint tube 116 and applying the pressure of the fluid to be detected directly to a sensitive member such as a bellows or a diaphragm, but the use of the pressure responsive switch 100 is not limited to this. That is, a temperature switch can be configured by connecting a temperature sensing tube to the element 115 in the pressure responsive switch 100 of this embodiment through a capillary and filling a closed space formed by the sensitive member, the capillary, and the temperature sensing tube with a refrigerant. In this way, in a temperature switch using the pressure responsive switch 100 of this embodiment, the sensitive member deforms or displaces in the vertical direction Z in response to the pressure inside the closed space, which changes in response to the temperature change detected by the temperature sensing tube, and the force generated by this deformation is transmitted to the lever 16 (responsive member), thereby changing the conductive state of the contacts.

[0046] In the present embodiment, the microswitch 1 is provided with a pair of levers 16, the corresponding actuation shaft 20, the switching means 30, the contacts 40, the terminals 50, etc., and constitutes a so-called dual type microswitch, but the present invention can be applied to various microswitches, not limited to dual type microswitches. In the present embodiment, in the manual reset mechanism 2, when the reset button 76 is not pressed, the reset shaft 71 is automatically displaced to the position before it was pressed by the biasing force of the reset spring 75, but this is not limited to this, and the reset button 76 may be not provided and the reset shaft 71 may be displaced to the position before it was pressed by manually operating the reset button 76. By keeping the reset button 76 pressed, the microswitch 1 can be used like the above-mentioned auto-reset type (automatic return type) microswitch. In addition, by removing the reset member 70, such as the reset shaft 71 and the reset plate 72, from the microswitch 1, the microswitch 1 can be used as the above-mentioned auto-reset type microswitch. [Explanation of symbols]

[0047] a Direction of travel b Regressive direction P1 Regulated position P2 Reset position 1 Microswitch 15 Rotating Axis 16 Lever 41 Fixed contact 42 Movable contact 70 Reset member (regulating part)

Claims

1. A microswitch comprising: a lever that rotates in a forward and backward directions about a rotation axis; a movable contact that performs a reversing operation in association with the rotation of the lever; a pair of fixed contacts with which the movable contact can be brought into electrical contact; and a determining portion that determines a position of the lever in the rotation direction, a rotation range of the lever includes a first reversal position where the reversal action occurs when the lever passes in the forward direction, and a second reversal position where the reversal action occurs when the lever passes in the backward direction, the regulating portion is provided so as to be displaceable between a regulating position where the rotation of the lever toward the retraction direction after passing the first reversal position in the forward direction is regulated between the first reversal position and the second reversal position, and a reset position where the lever toward the retraction direction is rotated until it passes the second reversal position.

2. The determining portion includes a reset plate that determines a position of the lever in the rotation direction, and a reset shaft that moves the reset plate forward and backward in an axial direction, 2. The microswitch according to claim 1, wherein the reset position is located on one side in the axial direction, and the restricting position is located on the other side in the axial direction.

3. a biasing means for biasing the reset shaft in the other axial direction, The defining portion is displaceable to the reset position by pushing the reset shaft toward one axial direction against the biasing force of the biasing means, 3. The microswitch according to claim 2, wherein the regulation portion is located at the regulated position when the reset shaft is not pressed.

4. A pressure responsive switch comprising the microswitch according to any one of claims 1 to 3.

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