JP2010123263A - Float switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a float switch capable of reducing a volume of a float. <P>SOLUTION: A rod 2 extends in a prescribed direction (for example, vertical direction to a liquid surface). The rod 2 is for example a rod-like member. The float 3 is installed at one end side of a rod 2, and supports the rod 2 by floating on a liquid surface. A hole 1a, which a fixing plate 1 has, makes the rod 2 to be inserted in free advance and retreat in a prescribed direction. For example, the hole 1a is a hole to penetrate the fixing plate 1 in a prescribed direction, and the rod 2 is penetrated through the hole 1a. A magnet 4 is for example installed on the rod 2. A lead switch 5 is installed on the rod 2 in the proximity of the magnet 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a float switch.

  Patent Document 1 discloses a float switch. The float switch includes a reed switch, a magnet for controlling on / off of the reed switch, a magnet attaching part to which the magnet is attached, and a float that floats on the liquid surface and supports the magnet attaching part.

  The reed switch is disposed through the magnet mounting portion and the float in a direction perpendicular to the liquid level.

  In such a float switch, the height of the float and the magnet mounting position varies with the variation of the liquid level. Depending on this variation, the distance between the magnet and the reed switch changes, and thus the on / off of the reed switch is controlled.

Japanese Patent Publication No. 8-17065

  The magnet mounting portion described in Patent Document 1 surrounds the reed switch so as to penetrate the reed switch. In other words, the magnet mounting portion has a through hole that allows the reed switch to pass therethrough. Since the through-hole was formed, the volume of the magnet mounting portion was relatively large, and the volume of the float supporting this was also relatively large.

  Therefore, an object of the present invention is to provide a float switch that can reduce the volume of the float.

  A first aspect of the float switch according to the present invention includes a housing (2) extending in a predetermined direction, a float (3) attached to the housing, and any one of the housing and the float. A magnet (4), a fixed plate (1) having a hole (1a) for allowing the casing to freely move back and forth in the predetermined direction, fixed to the outside, and attached to the fixed plate, And a reed switch (5) that opens and closes depending on the distance between them.

  A second aspect of the float switch according to the present invention is the float switch according to the first aspect, wherein the reed switch (5) is on the opposite side of the float (3) and on the fixed plate (1). The magnet (4) is attached to the housing (2) on the fixed plate side with respect to the float.

  A third aspect of the float switch according to the present invention is the float switch according to the first aspect, wherein the magnet (4) is provided on the float (3) and attached to the fixed plate (1). A case (6) extending along the predetermined direction toward the float side and accommodating the reed switch (5) on the float side is further provided.

  A fourth aspect of the float switch according to the present invention is the float switch according to any one of the first to third aspects, wherein the magnet (4) is embedded in the housing (2). Yes.

  A fifth aspect of the float switch according to the present invention is the float switch according to any one of the first to third aspects, wherein the magnet (4) is a surface of the housing (2) or the float ( It is attached to any of 3).

  When a float switch is used, the float floats on the liquid surface and supports the magnet by its buoyancy. The float alone can move not only in a predetermined direction according to the height of the liquid level but also in a direction parallel to the liquid level. The proximity / separation between the magnet and the reed switch in a direction other than the predetermined direction causes a malfunction of the float switch. Therefore, the moving direction of the magnet needs to be limited to a predetermined direction.

  In the first aspect of the float switch according to the present invention, a float is attached to the housing, and a fixing plate having a hole for freely inserting and retracting the housing is provided. Since the reed switch is attached to the fixed plate and the magnet is provided on the housing or the float, the moving direction of the magnet is limited to a predetermined direction. In addition, because of the positional relationship between the housing and the hole, the housing needs to be smaller in size than the fixing plate having the hole. That is, a small-capacity housing can be used, thereby reducing the weight supported by the float. Therefore, the required volume of the float can be reduced, and the occupied volume and manufacturing cost of the entire float switch can be reduced.

  In the 2nd aspect of the float switch which concerns on this invention, since a reed switch is arrange | positioned on a fixed board, a reed switch is hard to contact water. Therefore, reliability can be improved.

  In the third aspect of the float switch according to the present invention, since the distance between the reed switch and the fixing plate can be secured, even if a metal is used for improving the strength as the fixing plate, the lead made of the metal is used. The influence of magnetic characteristics on the switch can be suppressed. That is, the degree of freedom in selecting the material for the fixed plate is increased.

  According to the 4th aspect of the float switch which concerns on this invention, damage to the magnet by an impact can be suppressed.

  According to the 5th aspect of the float switch which concerns on this invention, manufacture of a housing is easy compared with the case where a magnet is embedded in a housing.

First embodiment.
FIG. 1 shows an example of a conceptual configuration of the float switch. The float switch is a device that detects the liquid level of the liquid level stored in the storage tank, for example. However, the storage tank is not shown in FIG. As shown in FIG. 1, the float switch includes a fixed plate 1, a housing 2, a float 3, a magnet 4, a reed switch 5, and a case 6.

  The housing 2 extends in a predetermined direction and has both ends in the predetermined direction. The housing 2 is a rod-shaped member formed of, for example, metal or resin.

  The float 3 is, for example, a polystyrene foam and is attached to the housing 2. In FIG. 1, the housing 2 is attached to one end side. Note that the housing 2 may penetrate the float 3. The float switch is arranged so that a predetermined direction is perpendicular to the liquid surface when used, and the float 3 floats on the liquid surface by the buoyancy and supports the housing 2. The casing 2 extends from the float 3 to the side opposite to the liquid level.

  The fixed plate 1 is fixed to a storage tank (not shown). The fixed plate 1 is made of, for example, metal or resin, and has, for example, a plate shape parallel to the liquid level. The fixing plate 1 has a hole 1a. The hole 1a allows the housing 2 to be freely inserted and retracted in a predetermined direction. For example, the hole 1a is a through-hole penetrating the fixed plate 1 in a predetermined direction, and the housing 2 penetrates the hole 1a so as to freely advance and retract in the predetermined direction.

  Moreover, the position of the housing 2 in a direction parallel to the liquid surface is determined within a predetermined range by loosely inserting the hole 1a in the predetermined direction. In other words, the hole 1a determines the position of the housing 2 in the direction parallel to the liquid level. Although the float 3 itself can move in a direction parallel to the liquid level, the housing 2 to which the float 3 is attached is positioned as described above.

  In FIG. 1, a stopper is provided at the other end of the housing 2. Specifically, a member 21 wider than the hole 1 a is provided at the other end of the housing 2 on the side opposite to the float 3 with respect to the fixed plate 1. The member 21 functions as a stopper. As a result, even if the liquid level of the liquid surface is lowered and the housing 2 is lowered with respect to the fixing plate 1 in the drawing downward direction, the member 21 comes into contact with the upper surface of the fixing plate 1 and the housing 2 is in the hole 1a. Can be prevented from falling out.

  The magnet 4 is attached to the housing 2 on the side opposite to the float 3 with respect to the fixed plate 1. In FIG. 1, the magnet 4 is attached to the upper surface of a member 21 that functions as a stopper. Then, as the liquid level on the liquid level rises and falls, the magnet 4 fixed to the float 3 via the housing 2 also moves up and down.

  The reed switch 5 is attached to the fixed plate 1 and opens and closes depending on the distance from the magnet 4. In FIG. 1, the reed switch 5 is attached to the fixed plate 1 in the vicinity of the magnet 4 on the side opposite to the float 3 with respect to the fixed plate 1. The reed switch 5 is connected to one end of the wiring 7. A connecting portion 8 such as a connector is attached to the other end of the wiring 7.

  The case 6 houses the reed switch 5. The case 6 houses the reed switch 5, and the space between the case 6 and the reed switch 5 is filled with resin. As a result, the reed switch 5 can be protected and the reliability can be improved.

  FIG. 2 shows an example of a conceptual configuration of the reed switch 5 and the case 6. The reed switch 5 includes two ferromagnets facing each other with a predetermined contact interval, and a glass tube enclosing the two ferromagnets. The two ferromagnetic bodies are electrically connected to the wirings 7a and 7b constituting the wiring 7, respectively. Referring again to FIG. 1, the magnet 4 exerts a magnetic action on the two ferromagnetic bodies, and the two ferromagnetic bodies are brought into contact with or separated from each other according to the distance between the magnet 4 and the reed switch 5. In other words, on / off of the reed switch 5 is controlled depending on the distance between the magnet 4 and the reed switch 5. For example, when the liquid level on the liquid level exceeds a predetermined value, the distance between the magnet 4 that moves up and down depending on the liquid level and the reed switch 5 exceeds a predetermined value, and the reed switch 5 is triggered by this. Turn on. As a result, the float switch can detect that the liquid level on the liquid surface has exceeded a predetermined value.

  This float switch is compared with the float switch disclosed in Patent Document 1. The proximity / separation between the magnet and the reed switch in a direction other than the predetermined direction causes a malfunction of the float switch. Therefore, the moving direction of the magnet needs to be limited to a predetermined direction. In the float switch described in Patent Document 1, the position of the magnet in the direction parallel to the liquid surface is determined by the penetration of the reed switch and the member to which the magnet is attached. The member has a through hole through which the reed switch passes. In other words, the member covers the periphery of the reed switch. On the other hand, in this float switch, the position of the magnet 4 in the direction parallel to the liquid level is determined by the housing 2 to which the magnet 4 is attached and the hole 1 a provided in the fixing plate 1. That is, the housing 2 to which the magnet 4 is attached does not need to cover the periphery of the reed switch 5 and can adopt a rod-like shape extending in a predetermined direction.

  As described above, since the magnet mounting member disclosed in Patent Document 1 forms a hole through which the reed switch passes, its volume is larger than that of the housing 2 that functions as a magnet mounting member. Conversely, according to the present float switch, the volume of the housing 2 can be reduced. Therefore, since the weight of the member (housing 2) supported by the float 3 can be reduced, the float 3 having a small volume can be used. Since the material cost of the float 3 is higher than that of other members, the manufacturing cost can be efficiently reduced. Moreover, the occupied volume of the whole float switch can also be reduced.

  Further, since the reed switch 5 is located on the side opposite to the float 3 with respect to the fixed plate 1, the reed switch 5 is difficult to be immersed in the liquid. Therefore, for example, even when the case 6 is cracked, it is difficult to cause a failure. Therefore, the reliability of the float switch can be improved.

  In addition, the magnet 4 should just exist in the upper part (opposite side of the float 3) with respect to the fixed plate 1, for example, may be provided in the side surface of the housing 2. FIG. An example of such an embodiment is shown in FIG. The housing 2 has an extending portion 22 extending in a predetermined direction from the upper surface of the member 21 that functions as a stopper, and the magnet 4 is attached to the side surface of the extending portion 22 on the reed switch 5 side. The effect mentioned above can be brought about also by such an aspect. Moreover, the magnet 4 may be attached to the side surface of the member 21 that functions as a stopper.

  Further, the magnet 4 may be embedded in the housing 2. An example of such an embodiment is shown in FIG. For example, the magnet 4 is embedded in a member 21 that functions as a stopper. The effect mentioned above can be brought about also by such an aspect. Furthermore, since the magnet 4 is protected by the housing 2, damage due to impact or the like can be prevented. Moreover, the magnet 4 may be embedded in the extending part 22 shown in FIG. 3, since the magnet 4 is not embedded in the housing 2, the housing 2 can be easily manufactured.

Second embodiment.
FIG. 5 shows another example of the conceptual configuration of the float switch. Compared with the float switch shown in FIG. 1, the installation direction of the reed switch 5 and the case 6 (hereinafter, this set is referred to as a switch part) and the installation position of the magnet 4 are different.

  The magnet 4 is provided on the float 3. Specifically, it is embedded in the float 3.

  The case 6 is attached to the fixed plate 1 and extends along the predetermined direction toward the float 3 side. In FIG. 3, the case 6 extends along a predetermined direction through a through hole 1 b provided in the fixed plate 1. The reed switch 5 is housed in a case 6 adjacent to the magnet 4 on the float 3 side.

  Even in such a float switch, a rod-like member can be adopted as the housing 2 supported by the float 3 as in the first embodiment, so that the volume of the float 3 can be reduced, and the production cost can be efficiently increased. Can be reduced.

  In the float switch according to the second embodiment, the reed switch 5 is housed on the float side of the case 6 extending from the fixed plate 1 in a predetermined direction. The distance between them can be secured. Therefore, even if a metal is used for improving the strength as the fixing plate 1, the influence of the magnetic characteristics on the reed switch 5 due to the metal can be suppressed. That is, the degree of freedom in selecting the material for the fixed portion can be increased.

  Similarly to the first embodiment, the magnet 4 may be provided on the side surface of the housing 2 on the reed switch 5 side, or may be embedded in the housing 2 at a position close to the reed switch 5. good.

  In addition, a set of the reed switch 5 and the case 6 (including the wiring 7) according to the first embodiment, the housing 2 and the fixing plate 1, and the reed switch 5 and the case 6 according to the second embodiment. It is desirable to employ the same set of one set (including the wiring 7), the casing 2 and the fixing plate 1 respectively. Thus, common components can be used in the float switches according to the first and second embodiments, the manufacturing cost can be reduced, and increase / decrease production of each float switch is facilitated.

It is a figure which shows an example of a notional structure of the float switch concerning 1st Embodiment. It is a figure which shows a reed switch and the case which accommodates this. It is a figure which shows another example of a notional structure of the float switch concerning 1st Embodiment. It is a figure which shows another example of a notional structure of the float switch concerning 1st Embodiment. It is a figure which shows an example of a notional structure of the float switch concerning 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixed part 2 Housing 3 Float 4 Magnet 5 Reed switch

Claims (5)

A housing (2) extending in a predetermined direction;
A float (3) attached to the housing;
A magnet (4) attached to either the housing or the float;
A fixing plate (1) having a hole (1a) for freely inserting and retracting the casing in the predetermined direction and fixed to the outside;
A float switch comprising a reed switch (5) attached to the fixed plate and opened / closed depending on a distance from the magnet.   The reed switch (5) is disposed on the fixed plate (1) on the side opposite to the float (3), and the magnet (4) is positioned on the fixed plate side with respect to the float. The float switch of claim 1, wherein the float switch is mounted on The magnet (4) is provided on the float (3),
The case further comprising: a case (6) attached to the fixing plate (1), extending along the predetermined direction toward the float side, and housing the reed switch (5) on the float side. The float switch described.   The float switch according to any one of claims 1 to 3, wherein the magnet (4) is embedded in the housing (2).   The float switch according to any one of claims 1 to 3, wherein the magnet (4) is attached to either the surface of the housing (2) or the float (3).

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