JPH0536179Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention can be used, for example, to issue an alarm when the amount of lubricating oil in the oil pan of an engine drops below the expected amount or when more than a predetermined amount is injected. This relates to a float-type liquid level detection switch, in particular:
This invention relates to improvements in short-circuiting electrodes provided on floats.

[Conventional technology]

BACKGROUND ART Conventionally, liquid level detection switches that issue an alarm when the remaining amount of lubricating oil in an engine has fallen below a predetermined level have been commonly used in the field of small general-purpose engines in Japan.
Additionally, many of these types of switches are of the float type. That is, a float equipped with a current-carrying electrode is immersed in lubricating oil, and two
(For example, Utility Model Application No. 127946/1983).

[The problem that the idea attempts to solve]

Generally, floats are made of foamed synthetic resin materials or hollow ones formed by powder molding or blow molding, but it is difficult to easily attach shorting electrodes to such floats. In other words, if we try to insert current-carrying electrodes into such a float, the mold becomes complicated, which significantly increases the cost, and it becomes difficult to balance the center of gravity, causing the float to tilt in the liquid. , there was a problem in which the accuracy of liquid level detection tended to decrease.

[Means to solve the problem]

The purpose of this invention is to obtain a float-type liquid level detection switch that is easy to attach a current-carrying electrode to the float and is reliable in operation. 6, and a float 8 to which a shorting electrode 4 is attached is movably housed inside the switch case 2.
In a device in which a fixed electrode 3 that cooperates with the short-circuiting electrode 4 is provided on either the upper or lower side in the vertical direction, the float 8 is formed relatively long and thin, and a short-circuit formed in the shape of a coil with a diameter slightly smaller than the float 8 is formed on the outer periphery of the float 8. The feature is that the electrode 4 is wound and attached elastically.

[Effect]

Since the shorting electrode 4 is made in the shape of a coil that is slightly smaller than the outer shape of the float 8, if it is fitted around the outer circumference of the float 8 in a slightly expanded state and the external force is removed, the float 8 will be moved by its elasticity. is tied to the outer circumference of the Further, the position of the short-circuit electrode is determined by opening the coil against the elasticity of the coil and moving the outer periphery of the float 8 in the axial direction.

〔Example〕

This invention will be explained below with reference to illustrated embodiments. In the figure, 1 is a float type liquid level detection switch, which is attached to a liquid tank such as an engine oil pan or crankcase, and is used with its tip inserted inside and immersed in oil or the like. The detection switch 1 is composed of a switch case 2, two fixed electrodes 3, 3 housed therein, and a short-circuit electrode 4 that interrupts conduction between them.

The switch case 2 consists of an injection-molded cup-shaped cover member 2a and a lid member 2b that closes the opening.One end of the fixed electrodes 3, 3 is inserted into the lid member 2b during molding, or is separately inserted in a later process. be combined. The other ends of the fixed electrodes 3, 3 are inserted into and supported by two rectangular through holes 5, 5 formed at the bottom of the cover member 2a, and by bending the protruding ends, the cover member 2a becomes a lid member. 2b so as not to separate. The switch case 2 is attached with the cover member 2a protruding into the oil tank, and lubricating oil of the engine is allowed to enter and exit through the oil passage hole 6 provided in the cover member 2a. Reference numeral 7 denotes a mounting hole provided in the lid member 2b, and the detection switch 1 is mounted to the oil tank with the fixed electrodes 3, 3 facing downward in the vertical direction. Note that the elongated protrusions 2c and 2d provided on the inner surfaces of the cover member 2a and the lid member 2b are used to prevent the end surface of the float 8 (described later) from sticking to the inner surface of the switch case 2 due to the viscosity of the lubricating oil, resulting in unstable operation. something that prevents
2e is an O-ring for sealing.

Each of the fixed electrodes 3, 3 is made by press-molding a brass plate material into the shape shown in the first figure, and has a connecting portion 3a that protrudes outward from the lid member 2b and is connected to the electric wire, and a connecting portion 3a that extends into the switch case 2. A contact portion 3b that cooperates with the shorting electrode 4, and a cup-shaped cover member 2a.
The cover member 2 extends outward through the cover member 2 and is bent.
a locking portion 3c for fixing the lid member 2b to the lid member 2b, and
It consists of an engaging portion 3d for ensuring insertion into the lid member 2b.

The shorting electrode 4 is a hard copper wire wound into a coil shape, and is elastically fitted around the outer periphery of the float 8. That is, the float 8 is formed in the shape of a rod made of synthetic resin foam, and the short-circuiting electrode 4, which is wound around the outer circumference in the form of a coil with a smaller diameter than the short-circuiting electrode 4, is slightly pushed open and the float 8 is inserted into the inside, and then an external force is applied. It was released and attached tightly.

Next, the operation of this embodiment will be explained. The detection switch 1 is installed in an oil tank with its axis in the horizontal direction, and when there is only a small amount of oil inside, the float 8 is placed above the two fixed electrodes 3, as shown by the broken line in FIG. The detection switch 1 is closed. When the lubricating oil is supplied to the oil tank and flows into the switch case 2, the float 8 floats up as shown by the solid line in the figure and disconnects the shorting electrode 4 from the fixed electrodes 3, 3. That is, the detection switch 1 is in the released state.

When the lubricating oil is consumed and the liquid level decreases, the float 8 descends as shown in FIG.
Make it possible to conduct electricity. This state is shown in Figure 4 b and c.
As shown in , even if the oil tank is tilted from side to side, its closed state is maintained stably. Note that this detection switch 1 is used not only for detecting the amount of remaining liquid in the liquid tank, but also for detecting the amount of remaining liquid in the liquid tank.
Of course, the above-described embodiment can also be installed upside down to detect excessive injection into the liquid tank.

[Effect of idea]

According to this invention, as described above, the short-circuiting electrode 4 corresponding to the fixed electrode 3 is made in the shape of a coil, and is fixed to the outer circumference of the float 8 by its elasticity. Compared to the case where the electrode 4 is inserted, the mold is simplified and the effort of molding can be saved. Furthermore, since the shorting electrode 4 can be easily moved on the float 8, it is easier to balance the weight compared to a structure in which the shorting electrode 4 is inserted or bonded. Furthermore, since the shorting electrode 4 is made of a coiled electric wire, it has the advantage of being able to withstand a large current compared to a structure in which the outer periphery of the float 8 is coated with conductive plating.

[Brief explanation of the drawing]

The drawing shows one embodiment of this invention.
The figure is an external view of the switch, FIG. 2 is a sectional view thereof, FIG. 3 is a sectional view thereof, FIGS.
b and c are drawings corresponding to the above-mentioned FIGS. 1, 2, and 3. 2...Switch case, 3...Fixed electrode, 4...
...Short circuit electrode, 8...Float.

Claims (1)

[Scope of utility model registration request] An oil hole 6 communicating between the inside and outside is provided in the switch case 2 that is immersed in the liquid, and the switch case 2
A float 8 with a short-circuiting electrode 4 attached thereon is movably accommodated therein, and a fixed electrode 3 that cooperates with the short-circuiting electrode 4 is provided on either the top or bottom of the float in the vertical direction, and the float 8 is formed to be relatively elongated. At the same time, a short-circuit electrode 4 formed in the form of a coil with a diameter slightly smaller than that is wound around the outer circumference of the short-circuit electrode 4 and is elastically attached to the float type liquid level detection switch.