JPH0316039Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is a liquid level detector that is installed inside a tank such as an oil tank and configured to detect when the liquid in the tank has decreased. This invention relates to a falling-off prevention device for movable contacts.

[Problems to be solved by the prior art and the invention] In general, in this type of liquid level detector, the movable contact provided on the float is held in the holder as the float falls under its own weight as the liquid level falls. There is a device that detects the liquid level by short-circuiting the receiving contact from above.

By the way, some of these liquid level detectors are used in places with strong vibrations, such as automobile oil tanks, and in that case, when the float vibrates following the vehicle body vibration in the short-circuited state, If the receiving contact is fixed relative to the holder and does not move, there is a problem that the short circuit condition is impaired and the liquid level detection becomes unstable. Therefore, the receiving contact is made flexible so that when the movable contact comes into contact with it, the receiving contact is elastically deformed downward under the weight of the float and comes into contact with the movable contact. Some devices are designed to ensure stable liquid level detection by causing the receiving contact to follow the movement of the movable contact as much as possible when the float vibrates in a short-circuited state.

However, in this case, there is a risk that the movable contact may fall off from the receiving contact, so as shown in FIG. This contact prevents the float 7 from lowering more than necessary and prevents the movable contact from falling off. However, in this case, until the cover body 9 is attached to the holder 2, the float is only supported in an extremely unstable state where the movable contact is only elastically received and supported by the receiving contact. Therefore, when assembling the liquid level detector, it is necessary to pay close attention to prevent the movable contact from falling off. Not only was the workability significantly inferior, but there was also the risk of being reassembled without realizing that something had come off, which was also a problem in terms of product management.

Therefore, it has been proposed to increase the plate thickness of the receiving contact so that the movable contact is firmly supported and held by the receiving contact so that it does not fall off, but in this case, the flexibility of the receiving contact is lost. Therefore, during detection, so-called contact sliding, in which the movable contact comes into contact with the receiving contact in a flexed state, cannot be achieved, and therefore the detection accuracy is significantly reduced, so it cannot be adopted.

[Means for solving the problem] In view of the above-mentioned circumstances, the present invention was created with the aim of providing a device for preventing the movable contact from falling off in a liquid level detector, which can eliminate these drawbacks. A float that moves downward as the liquid level falls, a movable contact provided on the float, a holder that holds a pair of terminals, and a receiving contact that extends laterally from the lower end of each terminal. and the receiving contacts have a free end shape and are flexible, and when the movable contact contacts each receiving contact from above to detect the liquid level based on the lowering of the float, each receiving contact In a liquid level detector configured such that the contact elastically deforms downward under the weight of the float and contacts a movable contact in a sliding state, the bottom of the holder has an opening at the bottom;
A contact chamber is formed in which the receiving contact and the movable contact are fitted in a vertically floating manner, and a contact chamber is further provided below the contact chamber of the holder at a lower position beyond the range of elastic deformation due to the weight of the float side of the receiving contact. A stopper is provided at a position before the movable contact comes off from the receiving contact to prevent the movable contact from falling from the receiving contact by abutting the movable contact from above to prevent the movable contact from falling. It is characterized by this.

With this configuration, the present invention makes it possible to reliably prevent the movable contact from falling off from the receiving contact even when the cover body is not attached.

[Example] Next, an example of the present invention will be described based on the drawings. In the drawing, 1 is a liquid level detector,
The holder 2 constituting the liquid level detector 1 is split in half, and the halves can be separated by pressing both halves 2a, 2a toward opposite sides with their divided surfaces facing each other. The holder 2 can be assembled integrally by fitting the protrusions 2b protruding from the other half 2a into the recesses 2c formed on the other half 2a. Fitting grooves 3a are formed into which the terminals 3, 3 fit, respectively. One end of the terminal 3 protrudes from the holder 2, and the lead wire 4 is welded thereto, but the other end (lower end) of the terminal 3
A base end portion of a receiving contact 5 formed in a thin plate shape is integrally fixed to the. The receiving contact 5 has a free end that protrudes laterally from the terminal 3, giving it flexibility and allowing it to bend up and down, but as described above, the terminal 3 is inserted into the fitting groove 3a. In the fitted state, the receiving contact 5 faces a contact chamber 2e formed at the bottom of the holder and having an open bottom. Furthermore, an edge 2d protrudes from the bottom peripheral edge of the holder 2;
A stopper 6, which will be described later, is integrally formed in a bridged state at an appropriate distance below the receiving contact 5 in its natural state housed in the contact chamber 2e.

On the other hand, 7 is a float formed in a cylindrical shape, and the float 7 is formed of a light material such as foamed polystyrene resin. The proximal end is integrally implanted. The movable contact 8 is positioned above the receiving contact 5 and is fitted into the contact chamber 2e in a loose manner, with protrusions 8a formed at both ends facing the tip position of the receiving contact 5 from above. It is set as follows. When the float 7 falls under its own weight due to a drop in the liquid level, the movable contact 8 contacts the receiving contact 5 from above, causing a short circuit between the terminals 3 and 3, thereby detecting the liquid level. but,
At this time, each receiving contact 5 is configured to contact the movable contact 8 in a contact sliding state in which it is elastically deformed downward under the weight of the float 7 side. Furthermore, the stopper 6 is disposed at an appropriate position below the receiving contact 5 at least beyond the range of elastic deformation due to the weight on the float 7 side and before the movable contact 8 comes off from the receiving contact 5. , and as a result of the float 7 receiving some kind of load directed downward, the receiving contact 5 is in a position further lowered beyond the normal range of elastic change due to the weight of the float, and the movable contact 8 is at the position where the receiving contact 5 is lowered. The movable contact 8 comes into contact with the stopper 6 from above at the position before it comes off, restricting the movable contact 8 from descending.
The stopper 6 is positioned so as to prevent it from falling off from the receiving contact 5.

Note that 9 is a cover body that is fitted into the holder 2 to cover the float 7, and the cover body 9 has an engagement protrusion 2f formed on the holder 2 that fits into an engagement hole 9a of the cover body 9. In some cases, it is attached integrally to the holder 2.

In the embodiment of the present invention configured as described above, the liquid level detector 1 is configured such that when the liquid level in the tank is lowered and the float 7 is lowered by its own weight, the movable contact 8 becomes the receiving contact. The liquid level detector 1 detects a drop in the liquid level by contacting the terminal 5 from above, and the liquid level detector 1 has a terminal 3 fitted into the half part 2a, and a movable contact 8 inserted into the groove 2e. When the float 7 is inserted and positioned above the receiving contact 5,
After the holder 2 is assembled, the holder 2 is assembled so that the halves 2a are brought into contact with each other, and then the cover body 9 is fitted onto the holder 2, thereby making it easy to assemble.

In the detection state, the receiving contact 5 is in contact with the movable contact 8 in a state where it is elastically deformed downward under the weight of the float 7, which causes the float 7 to swing due to vibration or the like. At this time, the bending receiving contact 5 is in a contact sliding state in which it moves following the movement of the movable contact 8, and stable liquid level detection is possible.

As described above, in the present invention, the liquid level is detected by bringing the movable contact 8 into contact with the flexible receiving contact from above in a sliding state, but the movable contact 8 is located in the contact chamber. 2c, the deflection of the receiving contact 5 due to the weight of the float 7 side is allowed by the stopper 6 formed on the holder 2.
When the movable contact 8 is bent further downward beyond this point, the stopper 6 prevents the movable contact 8 from descending any further, thereby preventing the movable contact 8 from falling off from the receiving contact 5. Therefore, when the receiving contact 5 and the movable contact 8 are assembled in the contact chamber 2c in a loose manner before the cover body 9 is assembled to the holder 2, it is already certain that the movable contact 8 will fall off from the receiving contact 5. This completely prevents the movable contact 8 from coming off when the cover body 9 is attached.

Moreover, the movable contact 8 is prevented from coming off.
Since the movable contact 8 is supported on both sides, it is possible to prevent the movable contact 8 from falling off even if a load greater than its own weight is applied to the float 7 during temporary assembly. It will always be maintained in an optimal state. For this reason, the wall thickness of the receiving contact 5 can be adjusted completely regardless of whether the movable contact 8 falls off.
By making the thickness optimal for making contact with the movable contact 8, the amount of deflection of the receiving contact 5 at the time of contact with the movable contact can be set to the maximum amount of deflection considering only the weight of the float 7. Therefore, Even if the positions of both receiving contacts 5 are shifted vertically, accurate detection can be performed without being affected by this.

[Operation and Effect] In summary, the present invention is constructed as described above, so that the movable contact comes into contact with the receiving contact in a bent state where it is elastically deformed downward under the weight of the float, and vibrations etc. As a result, when the float swings, the bent receiving contact becomes in a contact sliding state in which it moves following the movement of the movable contact, making it possible to stably detect the liquid level.

In this way, the receiving contact and the movable contact contact each other in a state where the contact slides under the weight of the float side, and stable liquid level detection is performed. Deflection under the weight of is allowed, and when the movable contact descends further beyond this point, the stopper located below the contact chamber restricts the movable contact from descending any further, and the movable contact moves away from the receiving contact. Prevents it from falling off. Therefore,
Before assembling the cover body to the holder, when the receiving contact and the movable contact are installed in the contact chamber in a loose manner, the falling of the movable contact from the receiving contact has already been reliably regulated, and the cover This completely prevents the movable contact from accidentally coming off when attaching the body.

Moreover, since the movable contact is prevented from falling off by supporting both sides of the movable contact, even if a load greater than its own weight is applied to the float during temporary assembly, the movable contact will not fall off. The wall thickness of the receiving contact can be completely eliminated and always maintained in an optimal state, so that the wall thickness of the receiving contact can be set to the optimal thickness to ensure favorable contact sliding with the movable contact, regardless of the possibility of the movable contact falling off. This means that highly accurate liquid level detection can be performed.

[Brief explanation of drawings]

The drawings show an embodiment of a device for preventing the movable contact from falling off in a liquid level detector according to the present invention. 3 is an exploded perspective view, FIG. 4 is a front view of a half part of the holder, and FIG. 5 is a partially cutaway front view of a conventional liquid level detector. In the figure, 1 is a liquid level detector, 2 is a holder, a dot drop prevention device, 5 is a receiving contact, 6 is a stopper, 7 is a float, and 8 is a movable contact.

Claims (1)

[Scope of utility model registration request] Consisting of a float that moves downward as the liquid level falls, a movable contact provided on the float, a holder that holds a pair of terminals, and a receiving contact that extends laterally from the lower end of each terminal, In addition, the receiving contacts have a free end shape and are flexible, and when the movable contact contacts each receiving contact from above to detect the liquid level based on the lowering of the float, each receiving contact is connected to the float side. In a liquid level detector configured to contact a movable contact in a sliding state, the bottom of the holder is open at the bottom and has a receiving contact and a movable contact. A contact chamber is formed in which the movable contact is fitted in a vertically floating manner, and a movable contact is located below the contact chamber of the holder beyond the range of elastic deformation due to the weight of the float side of the receiving contact. A stopper is provided at a position before the movable contact comes off from the receiving contact, so that both ends of the movable contact come into contact with each other from above to prevent the movable contact from falling. Features: A device to prevent movable contacts from falling off in liquid level detectors.