JP2009140721A - Adjusting screw and pressure switch using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adjusting screw that has a loosening prevention function and is firmly screwed with a female screw even if screwing is repeated many times, and a pressure switch using the same. <P>SOLUTION: The adjusting screw 1 has the following configuration. At least a screw part is made of a resin. The adjusting screw has a plurality of protrusions 16a, 16b, and 16c-16x-16n being part of a peripheral direction of the screw part and locally making the depths of screw valley parts 15 shallow over a prescribed distance in the longitudinal direction. Each of the plurality of protrusions 16a, 16b, and 16c-16x-16n forms each screw loosening prevention part 16. Therefore, the adjusting screw has a loosening prevention function and is firmly screwed with a female screw even if screwing is repeated many times. Here is also provided the pressure switch 100 using the adjusting screw. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an adjustment screw having a function of preventing loosening and a pressure switch using the adjustment screw.

  A set screw called a so-called potato screw is conventionally known. A pressure switch having a snap action mechanism, which can finely adjust the on / off operating point of the switch by using a set screw as an adjustment screw, is also known (for example, Patent Document 1). reference).

  As described in Patent Document 1, this pressure switch partitions a hollow housing and the inside of the housing to form two pressure chambers, and generates an operating force corresponding to the pressure difference between these pressure chambers. An external force transmission mechanism, a gas introduction hole provided in the housing corresponding to each of the two pressure chambers, and a snap action mechanism that is accommodated in one of the pressure chambers and operates in response to an operating force from the external force transmission mechanism And an electrical contact that is opened and closed by a snap action mechanism, and a conductive member that transmits the opening and closing of the electrical contact to the outside of the housing.

Then, the snap action mechanism is a first in which the distal end portion is spaced from and opposed to each other in a state where the movable portion side cutout portions are formed on both sides of the distal end portion, and the proximal end portion is fixed via the elastic deformation portion. And a second spring part and a leaf spring side notch part that engages with the opposing notch part of the movable part are formed on both sides of both end parts, and is inserted between the movable parts in a curved manner. A leaf spring is provided that is engaged with the movable part side notch part of each movable part via the notch part and applies a spring force to each movable part. In the initial state of the first movable part, the second movable part is held at the first position, and when the first movable part is displaced and exceeds the operating point, the second movable part is moved to the other side. It has a structure that reverses rapidly.
WO 2006/090797 (page 6-10, FIG. 1).

  The snap action mechanism having such a configuration is an elastically deformable portion continuously connected to the first and second movable portions via an adjusting screw in order to adjust the on / off operating point of the pressure switch to an optimum one. The amount of bending is finely adjusted.

  However, such an adjustment screw requires fine adjustment over a certain amount of time so that the pressure switch is turned on and off in an optimum state. For this reason, in an adjustment screw having a conventional structure, in this adjustment process, the tightening resistance between the adjustment screw and the main body into which the adjustment screw is screwed is reduced to cause backlash, and the adjustment screw is often loosened.

  In such a case, when the adjustment screw is screwed in, it has to be screwed in a state where a lock nut is applied around the adjustment screw, which increases the number of steps and increases the cost.

  An object of the present invention is to provide an adjustment screw having a locking function and a pressure switch using the adjustment screw.

In order to solve the above-described problem, an adjusting screw according to claim 1 of the present invention is provided.
At least the threaded portion is made of resin, and has a plurality of protrusions that are part of the circumferential direction of the threaded portion and locally reduce the depth of the threaded valley portion over a predetermined distance in the longitudinal direction. The plurality of protrusions form a screw loosening prevention portion.

  By providing a plurality of protrusions that form such screw loosening prevention portions at predetermined positions in the circumferential direction of the valley of the adjustment screw, each protrusion is difficult to engage with the female screw on the other side when the adjustment screw is screwed. The adjustment screw is not loosened by backlash, and the adjustment screw can be screwed in with a sufficient tightening force.

Moreover, the pressure switch according to claim 2 of the present invention is
A hollow housing;
An external force transmission mechanism for partitioning the inside of the housing to form two pressure chambers and generating an operating force according to the differential pressure between these pressure chambers;
A gas introduction hole provided in the housing corresponding to each of the two pressure chambers;
A snap action mechanism that is housed in any of the pressure chambers and operates in response to an operating force from the external force transmission mechanism;
Electrical contacts opened and closed by the snap action mechanism;
In the pressure switch including a conductive member that transmits the opening and closing of the electrical contact to the outside of the housing,
The snap action mechanism includes first and second movable portions, each of which has a distal end portion arranged opposite to each other and a base end portion fixed via an elastic deformation portion, and first and second ends opposite to each other. An initial state of the first movable part, including a leaf spring that is inserted in a curved manner between the movable parts in a state of being engaged with the distal end part of the movable part, and applies a spring force to each movable part. The second movable part is held at the first position, and when the first movable part is displaced via the external force transmission mechanism and exceeds the operating point, the second movable part is moved to the other side. A pressure switch that is rapidly reversed and held in the second position,
The amount of bending of at least one of the first and second movable parts can be adjusted using the adjusting screw according to claim 1.

Moreover, the pressure switch according to claim 3 of the present invention is the pressure switch according to claim 2,
The holding position of at least one of the first position and the second position can be adjusted using the adjusting screw according to claim 1, instead of the amount of bending of the elastic deformation portion. It is said.

  By using such an adjustment screw for the pressure switch, it is difficult to loosen when the adjustment screw is tightened into the female screw of the pressure switch. It is possible to prevent the adjustment screw once screwed from loosening due to backlash and changing the on / off operating point of the pressure switch.

  ADVANTAGE OF THE INVENTION According to this invention, the adjustment screw which has a locking function, and a pressure switch using the same can be provided.

  Hereinafter, an adjusting screw and a pressure switch using the same according to an embodiment of the present invention will be described with reference to the drawings. The adjustment screw 1 according to an embodiment of the present invention shown in FIGS. 1 to 4 is made of a resin excellent in strength and moldability, and has an outer shape equivalent to that of a conventional adjustment screw. That is, the male screw 11 is formed on the entire circumference over substantially the entire longitudinal direction of the adjusting screw, and the protrusion 12 that comes into contact with the object to be adjusted is provided at one end, and the adjusting screw is tightened at the other end. A hexagonal hole 13 for forming or loosening is formed. Instead of the hexagonal hole 13, a hole matching the shape of a screwdriver such as a Phillips screwdriver may be formed. However, the adjustment screw 1 according to this embodiment is different from the conventional adjustment screw in the following points.

  Specifically, the adjustment screw 1 according to the present embodiment has a plurality of heights that are lower than the peak portion 14 of the adjustment screw 1 and slightly shallow in the depth of the valley portion 15 at two locations facing each other in the diameter direction. 16n of the projections 16a, 16b, 16c,..., 16n are arranged in a straight line over the entire longitudinal direction of the screw and have a screw loosening prevention portion 16. And each protrusion part 16a, 16b, 16c ... 16x ... 16n which comprises the screw | thread loosening prevention part 16 comprises cross-sectional triangle shape, and as shown in FIG. 4, the vertex is formed in this embodiment.

  Since the adjusting screw 1 is made of resin, it is formed by injection molding in a state in which two dies are combined at the time of manufacture. In the case of the present embodiment, the above-described screw loosening prevention portion 16 is formed using a parting line of a two-part mold. Specifically, the screw loosening prevention portion 16 composed of the plurality of protrusions 16a, 16b, 16c,... 16x,... 16n makes a slight depth of cut in the parting line of the mold when the adjustment screw 1 is formed. By forming the resin, the resin enters the notch at the time of injection molding, and the screw loosening prevention portion 16 corresponding to the notch is formed at two locations opposed to the diameter direction of the adjusting screw 1.

  In the case of this embodiment, each of the protrusions 16a, 16b, 16c ... 16x ... 16n constituting the screw loosening prevention portion 16 has a triangular cross section as described above, and its apex is pointed. It can be easily formed by cutting a part of the thread part of the parting line corresponding to the valley part 15 of the adjusting screw 1 using a cutting tool whose tip side is sharply sharpened along the parting line. . In FIG. 4, the two protrusions 16 are formed at positions on the outer periphery of the screw that face each other in the diametrical direction. However, the present invention is not limited to this. You may form the three protrusion parts 16 in the position where a center angle makes | forms mutually 120 degree | times. Moreover, it is not necessary to arrange each protrusion 16 at a position where the central angles become equal, and each protrusion 16 may be disposed at a position where the central angles become uneven.

  In addition, the cross-sectional shape of each protrusion part which comprises the screw | thread loosening prevention part 16 is not limited to making a cross-sectional triangle shape as mentioned above, The chevron-shaped cross-sectional shape where the receiving part of each protrusion part was rounded is used. You may have, and the cross-sectional shape of each projection part may have trapezoid shape or a rectangular shape. That is, by appropriately changing the cross-sectional shape of the cutting tool that cuts the thread portion of the mold along the parting line of the mold, it is possible to selectively form the screw loosening prevention portions having these different cross-sectional shapes. .

  By adjusting the spring pressure of the pressure switch 100, which will be described later, using such an adjustment screw 1, projections 16a, 16b, 16c,... 16x that are continuous with the female screw that is screwed in when the adjustment screw 1 is screwed in. ... The screw loosening prevention portion 16 made of 16n generates an appropriate tightening resistance force when screwed. As a result, an appropriate force is required for screwing, enabling fine adjustment of the screwing amount and preventing slack due to backlash that occurs in a conventional adjusting screw.

  Further, even when the adjustment screw 1 once screwed is loosened or tightened again, the screw loosening prevention portion 16 of the adjustment screw 1 is not easily loosened during this time, so that the adjustment screw 1 is difficult to loosen. That is, backlash caused by backlash that occurs when the adjustment screw is screwed into the female screw of the main body made of resin, such as a conventional adjustment screw made of metal or resin, occurs in the adjustment screw 1 according to the present embodiment. There is nothing.

  Subsequently, a pressure switch 100 in which the adjustment screw 1 according to the present embodiment is used will be described with reference to the drawings. As shown in FIG. 5, the pressure switch 100 includes a resinous housing 110, a resinous cover 120 fitted to the housing 110, and a space formed by the housing 110 and the cover 120 as a high-pressure side space HP. A resinous diaphragm 130 and a center plate 140 defined in the low pressure side space LP are provided.

  The housing 110 is provided with a low-pressure side pipe connection port 115, and the cover 120 is provided with a high-pressure side pipe connection port 125. Further, the center plate 140 has a plunger 141 protruding toward the low-pressure side space at the center thereof.

  Further, a snap action mechanism and a switch unit 190, which will be described in detail later, are provided in the low pressure side space, and the switch unit 190 is turned on and off via the snap action mechanism by the pressing force of the plunger 141. ing.

  The low-pressure side pipe connection port 115 and the high-pressure side pipe connection port 125 are each installed, for example, in the combustion air supply part of the water heater, and the plunger 141 is moved in one direction according to the pressure change caused by the operation of the air supply fan. The air supply fan is turned on to check the normal operation of the air supply fan, and the plunger is moved in the other direction according to the pressure change caused by the stop of the air supply fan to turn off the air supply fan. The fan stop status is checked.

  Next, the snap action function of the pressure switch 100 and the operation of the switch unit 190 will be described in more detail based on the drawings.

  The snap action function includes a base plate 150 shown in FIG. 6 that is partially fixed to the columns 111a, 111b, and 111c shown in FIG. A diagram in which the first movable portion 160 and the second movable portion 170 arranged opposite to each other and both ends of the first movable portion 160 and the second movable portion 160 and 170 engage with each other, and elastically deformed into a C shape in a side view as a whole. A C spring 180 shown in FIG.

  As shown in FIG. 6A, the base plate 150 has a frame portion 151 having a rectangular shape in plan view, and the first movable portion 160 protrudes from one short side 152 of the frame portion 151 inward in the frame portion longitudinal direction. A second movable portion 170 protrudes from the other short side 153 of the frame portion 151 toward the inside in the frame portion longitudinal direction.

  And the edge part 154f of the long side 154 of the flame | frame part 151 is bend | folded, and functions as a rigid body. Further, the frame portion 151 is fixed to the support pillars 111a, 111b, 111c of the housing 110 by the fixing portion 153b of one short side 152 and the fixing portions 154a, c of the long side 154 in the vicinity of each short side shown in FIG. It is fixed.

  The first movable portion 160 has an opening 161 for adjusting the spring force, and is integrally connected to the elastic deformation portion 162 integrally connected to one short side 152 of the frame portion 151, and is connected to the side. A C spring locking portion 163 that functions as a rigid body is provided via a bent portion 163a. A plunger receiving recess 164 (see FIG. 6B) is formed in the vicinity of the tip of the first movable portion 160.

  A C spring locking notch 163b (see FIG. 6A) is formed at the tip of the C spring locking portion 163, and one end 183 of the C spring 180 is formed as shown in FIG. 8B. The notch 183a is engaged with the notch 163b for locking the C spring.

  As shown in FIG. 6A, one short side 152 of the frame portion 151 is provided with a load adjustment plate 155 on the upper side and a load adjustment plate 156 on the lower side. Thereby, one short side 152 of the frame part 151 functions as a rigid body. The load adjustment plate 156 is substantially T-shaped in a plan view, and the projecting portion 157 to the inside of the frame portion 151 is located just inside the opening of the first movable portion 160 in the plan view shown in FIG. It is attached to one short side 152 of the frame portion 151. The vicinity of the tip of the protrusion 157 of the load adjustment plate 156 is an adjustment screw contact portion 158 (see FIG. 7) with which the tip of the adjustment screw 1 contacts.

  The adjustment screw contact portion 158 of the load adjustment plate 156 is displaced by a distance A inward from the fixing portion 154a of the frame portion 151 as shown in FIG. Then, by pushing up the adjustment screw contact portion 158 with the adjustment screw 1 by the displacement amount of the distance A, the protruding portion 157 of the load adjustment plate 156 is bent and the elastic deformation portion 162 of the first movable portion 160 is bent. It has become.

  As shown in FIG. 6, the second movable portion 170 is formed with an elastic adjustment opening 171 on the inner side, and is formed as an elastic deformation portion having higher rigidity as a whole than the first movable portion 160. Further, a C spring engaging notch 172 (see FIG. 6B) is formed at the tip of the second movable portion 170, and the other end 184 of the C spring 180 is formed as shown in FIG. 8B. To engage.

  The C spring 180 has a rectangular shape as shown in FIG. 8A in a free state, and has two openings 181 and 182 for elastic adjustment adjacent to each other in the longitudinal direction and both ends in the longitudinal direction. Notches 183a and 184a that engage with the tip ends of the first and second movable parts 160 and 170 described above are provided on both sides in the vicinity of the part.

  As shown in FIG. 9, the switch unit 190 includes an electrical contact made up of a NO (Normally Open) terminal 191 provided on the upper side in the drawing and an NC (Normally Close) terminal 192 provided on the lower side. And an electrical contact comprising a COM (Common) terminal (not shown). The NO terminal 191 and the NC terminal 192 are fixed to the housing 110 by fixing members 193 and 194, respectively. The fixing position of the NC terminal 192 can be adjusted by the adjusting screw 1 with respect to the interval between the NO terminals 191. The COM terminal is configured to electrically transmit the open / closed state of the electrical contact to the outside of the pressure switch 100 via a conductive member not shown in detail here. Then, the switch unit 190 maintains either the state in which the second movable unit 170 comes into contact with the NO terminal 191 or the NC terminal 192 in accordance with a pressure difference acting on the diaphragm 130 by a snap action function described later. It is supposed to be.

  Next, the operation of the pressure switch 100 including the relationship with the adjustment screw 1 according to the present embodiment will be described. FIG. 9 is an operation explanatory view of the pressure switch 100 in a state where the load adjusting plate 156 is not bent by the adjusting screw 1. FIG. 9A shows a state in which the plunger 141 of the center plate 140 (not shown in FIG. 9) is positioned upward in a state where the pressure of the high-pressure side pipe connection port is not high. ) Shows a state in which the plunger 141 of the center plate 140 (not shown in FIG. 9) is positioned below in a state where the pressure of the high-pressure side pipe connection port 125 is high.

  In FIG. 9A, the elastic repulsive force of the C spring 180 acts on the first and second movable parts 160 and 170 in the direction of the arrows in the figure, respectively, and the tip of the first movable part 160 is the common horizontal plane. While the C spring 180 is positioned above the (the surface including both long sides 154 of the frame portion 151), the tip of the second movable portion 170 is positioned below the common horizontal plane. An elastic repulsive force is exerted on 170. As a result, the contact point of the movable portion 170 is in contact with the NC terminal 192 to maintain this state. When the pressure of the high-pressure side pipe connection port 125 becomes high, the plunger 141 moves downward in the figure due to the downward displacement of the center plate 140 accompanying the deformation of the diaphragm 130.

  As a result, the tip of the plunger 141 presses the tip of the first movable portion 160 downward, and as shown in FIG. 9B, the C spring 180 is suddenly angularly displaced in the counterclockwise direction in FIG. The posture of the spring 180 changes. In response to this, the other end of the C spring 180 pushes the tip of the second movable portion 170 upward, and the tip of the first movable portion 160 is caused by the elastic deformation force of the C spring 180 indicated by an arrow in the figure. The portion is positioned below the common horizontal plane (the plane including both long sides 154 of the frame portion 151) in the drawing so that the tip of the second movable portion 170 is kept above the common horizontal plane in the drawing. To change. As a result, the contact of the movable portion 170 contacts the NO terminal 191 and maintains this state.

  On the other hand, when the pressure of the high-pressure side pipe connection port 125 shifts from a high pressure state to a low pressure state, the state shown in FIG. 9B is based on the operation principle opposite to the operation principle of the snap action described above. Then, the state returns to the state of FIG.

  FIG. 10 is a diagram for explaining the operation of the pressure switch 100 that is basically the same as that in FIG. 9. FIG. 10A shows the inside of the pressure switch when the pressure of the high-pressure side pipe connection port 125 is not high. FIG. 10B shows a state inside the pressure switch when the pressure of the high-pressure side pipe connection port 125 is high.

  Here, FIG. 10 differs from FIG. 9 in that the adjustment screw 1 is further screwed into the housing from the state of FIG. 9 and the protruding portion 157 of the load adjustment plate 156 contacting the protrusion 12 at the tip of the adjustment screw 1 is shown. The first movable part tip is strongly pressed by the plunger 141 along with the pushing up to the middle upper side. This is because the load adjusting plate 156 is bent by pushing up the protruding portion 157 of the load adjusting plate 156 with the adjusting screw 1 by the displacement amount of the distance A shown in FIG. 7, and the elastic deforming portion 162 of the first movable portion 160 is deformed. This is based on the fact that it has become more flexible. Since the position of the tip of the first movable part 160 is regulated by the plunger 141, the amount of bending of the first movable part 160 can be further increased by strongly pressing the tip of the first movable part with the plunger 141. Instead of increasing, the amount of bending increases the elastic force in the initial state of the first movable part 160 as shown in FIG.

  As a result, the snap action function does not work and the state shown in FIG. 10B is not reached unless a large pressing force is applied to the plunger 141 to push down the tip of the first movable portion 160 downward in the figure. Become. As a result, the operating point of the pressure switch-on can be shifted (adjusted) so that it does not operate unless the pressure on the high-pressure side pipe connection port side becomes higher than the state shown in FIG.

  Note that the amount of movement of the adjusting screw 1 in FIG. 10 relative to FIG. 9 is exaggerated for ease of understanding of the description, but in actual adjustment, a slight screwing operation of the adjusting screw 1 or vice versa. The operating point of pressure switch-on can be changed by changing the elastic force of the first movable part 160 by the operation.

  Here, when the housing into which the adjustment screw is screwed is made of resin as in the present embodiment, the conventional adjustment screw is used, and the adjustment screw is screwed at the optimum position to be optimal for the first movable part. Even if the adjustment is performed so that a large elastic force is generated, the elastic force acting on the first movable portion changes due to the looseness of the adjustment screw due to the backlash.

  Specifically, although the adjustment screw is screwed to the position shown in FIG. 10A, the adjustment screw may be loosened and return to the position shown in FIG. 9A. As a result, the balance between the elastic repulsive force of the C spring 180 and the elastic force of the first movable portion 160 deviates from the optimum state, and the desired plunger pressing force, that is, the high pressure side pipe connection port 125 and the low pressure side pipe connection. Even if the differential pressure of the air introduced from the port 115 is other than the desired differential pressure, the pressure switch 100 may be turned on / off. Therefore, an extra step of applying a screw lock or the like immediately before screwing the adjustment screw into the screw hole of the housing is required, which increases the manufacturing cost of the pressure switch.

  However, in the case of the pressure switch 100 using the adjustment screw 1 according to this embodiment, the adjustment screw 1 is screwed into the screw hole of the housing 110 made of resin, and the screwing amount is finely adjusted many times in the adjustment process. But backlash does not cause slack. Thus, once the adjustment of the elastic force of the first movable part 160 in FIG. 10A is performed, the elastic force of the first movable part 160 due to the loosening of the adjusting screw 1 does not shift, and the pressure switch The on / off operating point of 100 does not shift. In this case, it is more preferable that after the adjustment screw 1 is screwed to the optimum position, the screw portion is filled with a sealing material that also serves as an adhesive.

  The adjusting screw 1 described above can also be used when adjusting the holding position of the NC terminal 192 in the present embodiment. Specifically, by changing the screwing amount of the right adjustment screw 1 shown in FIG. 10, the vertical position of the fixing member 194 in FIG. 10B is adjusted, and thereby the C spring 180 and the second movable member are moved. The relative positional relationship with the portion 170 can be changed, and the balance relationship between the elastic repulsion force of the C spring 180 and the elastic force of the second movable portion 170 can be changed. As a result, the pressing force of the plunger 141 at the time of transition from FIG. 10B to FIG. 10A, that is, the differential pressure between the high-pressure side pipe connection port 125 and the low-pressure side pipe connection port 115 can be changed. It is possible to change the off operating point.

  Even in this case, the adjusting screw 1 according to the present embodiment exhibits the same operation as that described above. In other words, with the conventional adjustment screw, once it is tightened, it loosens and the holding position of the NC terminal 192 changes, and as a result, the operating point of the pressure switch off may deviate from the optimum position during adjustment. It has been necessary to adjust the screwing amount of the adjusting screw in a state where a screw lock or the like is applied to the adjusting screw in advance. However, by using the adjustment screw 1 in this embodiment, the adjustment screw 1 is less likely to loosen, and once the operating point of the pressure switch off is adjusted with the adjusting screw 1, this operating point is shifted thereafter. To prevent. Note that the combination of the material of the adjusting screw 1 and the material of the housing 110 does not significantly affect the effect of locking. That is, in order to carry out the present invention, an arbitrary resin is selected from general engineering plastics such as PC, PBT, and PPS to form the adjusting screw 1, and similarly, an arbitrary resin is selected and the housing is selected. 110 can be formed and used in combination.

  Since the structure of the adjusting screw according to the present invention is not limited to the above-described embodiment, a modified example of the above-described adjusting screw will be described below. As shown in FIG. 11, the adjustment screw 2 according to this modification is formed, for example, by forming a part of the insertion side of the adjustment screw 2 as a normal male screw 21, and from a position separated by a certain distance from the end of the insertion side. A screw loosening prevention portion 26 is formed continuously from the trough portion 25, which is a linear series of the protruding portions 26a, 26b, 26c... 26x. By forming such an adjustment screw 2, smooth insertion is performed when the adjustment screw 2 is inserted into the body, and when the adjustment screw 2 is screwed to some extent, the screw loosening prevention portion 26 is not easily inserted into the female screw. It becomes to be screwed firmly. In this way, the adjustment screw 2 can be inserted and adjusted easily. A female screw hole for screwing the adjusting screw 2 into the housing 110 is formed in the housing 110 in advance. Or you may employ | adopt what is called a self-tapping system which forms an internal thread by screwing the adjustment screw 2 in the pilot hole which the internal thread is not engraved.

  Note that the adjustment screws 1 and 2 according to the present embodiment and the modifications thereof are limited to the provision of screw loosening prevention portions at two locations that are circumferentially opposed to each other in the diameter direction, but are not necessarily limited thereto. Alternatively, such screw loosening prevention portions may be formed at one place or three places in the circumferential direction. However, it is possible to reduce the manufacturing cost of the mold by forming the screw loosening prevention portion according to the parting line of the adjustment screw forming mold.

  In the above-described embodiment, the entire adjustment screw is made of resin. However, in the present invention, at least the screw portion only needs to be made of resin. That is, for example, the present invention can be applied to a composite adjustment screw in which the central portion is integrally formed of metal and the screw portion is integrally formed of resin.

  As described above, the adjustment screw according to the present invention is provided with a protruding portion that forms a linear screw loosening prevention portion continuously from the valley portion at a predetermined position in the circumferential direction of the adjustment screw, so that the adjustment screw can be screwed in. That portion is screwed into the female screw on the main body side, and the adjusting screw can be screwed with a sufficient tightening force without loosening the adjusting screw when screwed.

  In addition, by using the adjustment screw according to the present invention for the pressure switch having the above-described structure, it is possible to prevent the adjustment screw from loosening when the adjustment screw is screwed in or after the screw is screwed in and changing the on / off operation point of the pressure switch. be able to. Therefore, an extra work such as applying a lock nut is not required when the adjustment screw of the pressure switch is screwed.

It is a perspective view which shows the adjusting screw which concerns on one Embodiment of this invention. FIG. 2 is a perspective view showing the adjustment screw shown in FIG. 1 slightly rotated in the axial direction. FIG. 4 is a side view of the adjustment screw shown in FIGS. 1 to 3. It is sectional drawing along the direction orthogonal to an axial direction in the formation part of the screw loosening prevention part of the adjustment screw shown in FIG.1 and FIG.2. It is sectional drawing which shows the internal structure of the pressure switch using the adjusting screw shown in FIG. FIG. 6 is an exploded perspective view (FIG. 6A) of a base plate used in the pressure switch shown in FIG. 5 and an integrated perspective view (FIG. 6B). It is a top view of the base board shown in FIG. FIG. 8A is a plan view of a C spring used in the pressure switch shown in FIG. 5 and a state in which the C spring is engaged with the first movable part and the second movable part shown in FIG. It is a front view (FIG.8 (b)). FIG. 9A is a side view schematically showing a state before and after the operation of the pressure switch before adjustment by the adjustment screw, and FIG. 9A shows a state where the plunger is not pressed against the first movable part. b) shows a state where the plunger is pressed against the first movable part. FIG. 10A is a side view schematically showing a state before and after the operation of the pressure switch after the adjustment with the adjustment screw, and FIG. 10A shows a state where the plunger is not pressed against the first movable part. (B) has shown the state which the plunger is pressing with the 1st movable part. It is a perspective view which shows the modification of the adjustment screw of FIG.

Explanation of symbols

1, 2 Adjustment screw 11 Male screw 12 Protruding part 13 Hexagonal hole 14 Mountain part 15 Valley part 16 Screw loosening prevention part 16a, 16b, 16c ... 16x ... 16n Protrusion part 21 Male screw 25 Valley part 26 Screw loosening prevention part 26a, 26b 26c ... 26x ... 26n Protrusion part 100 Pressure switch 110 Housing 111a, 111b, 111c Post 115 Low pressure side pipe connection port 120 Cover 125 High pressure side pipe connection port 130 Diaphragm 140 Center plate 141 Plunger 150 Base plate 151 Frame part 152 On the other hand Short side 153 The other short side 153b One short side fixed part 154 Long side 154a, 154c Fixed part 154f Edge part 155 Load adjustment pad 156 Load adjustment plate 157 Load adjustment plate protrusion 158 Adjustment screw contact part 160 First possible Moving part 161 Opening part 162 Elastic deformation part 163 C spring locking part 163a Bending part 163b C spring locking notch part 164 Recessed part 170 Second movable part 171 Elastic adjustment opening part 172 C Spring engaging notch part 180 C Spring 181, 182 Opening 183 One end 184 Other end 183 a, 184 a Notch 190 Switch 191 NO (Normally Open) terminal 192 NC (Normally Close) terminal 193, 194 Fixed member HP High pressure side space LP Low pressure side space

Claims (3)

  At least the threaded portion is made of resin, and has a plurality of protrusions that are part of the circumferential direction of the threaded portion and locally reduce the depth of the threaded valley portion over a predetermined distance in the longitudinal direction. The adjustment screw, wherein the plurality of protrusions form a screw loosening prevention portion. A hollow housing;
An external force transmission mechanism for partitioning the inside of the housing to form two pressure chambers and generating an operating force according to the differential pressure between these pressure chambers;
A gas introduction hole provided in the housing corresponding to each of the two pressure chambers;
A snap action mechanism that is housed in any of the pressure chambers and operates in response to an operating force from the external force transmission mechanism;
Electrical contacts opened and closed by the snap action mechanism;
In the pressure switch including a conductive member that transmits the opening and closing of the electrical contact to the outside of the housing,
The snap action mechanism includes first and second movable portions, each of which has a distal end portion arranged opposite to each other and a base end portion fixed via an elastic deformation portion, and first and second ends opposite to each other. An initial state of the first movable part, including a leaf spring that is inserted in a curved manner between the movable parts in a state of being engaged with the distal end part of the movable part, and applies a spring force to each movable part. The second movable part is held at the first position, and when the first movable part is displaced via the external force transmission mechanism and exceeds the operating point, the second movable part is moved to the other side. A mechanism for rapidly reversing and holding in the second position;
The pressure switch according to claim 1, wherein the amount of bending of at least one of the first and second movable parts can be adjusted using the adjusting screw according to claim 1. The holding position of at least one of the first position and the second position can be adjusted using the adjusting screw according to claim 1, instead of the amount of bending of the elastic deformation portion. The pressure switch according to claim 2.

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