JP2509067Y2 - Electronic scales - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of an electronic scale having a waterproof structure.

[0002]

2. Description of the Related Art As is well known, an electronic balance constructed by using a load cell detects tensile strain and compressive strain of a strain generating portion generated when a weight of an object to be weighed is applied to a strain gauge. Such a strain detecting element electrically detects and weighs. Therefore, since the electronic scale is provided with an electronic circuit connected to the load cell, when the electronic scale is used in a place rich in water, it has been conventionally made to have a watertight structure.

[0003]

An electronic scale is manufactured according to an object to be weighed, and the weighing range of the electronic scale is determined by the weight range of the object to be weighed. The shape and size of the electronic scale are also selected. Therefore, the size of the case that houses the load cell and the electronic circuit board of the electronic scale will also change in various ways.However, in such an electronic scale that requires a watertight structure, the length of the case seal part will vary. However, since the size varies depending on the size, the commonality of the packing used for the seal portion is lost, and there is an uneconomical need to prepare various kinds of packing. Further, as the case size increases, the tightening pressure at the seal portion tends to vary, which causes water leakage and causes poor waterproofing. And, if the above-mentioned tightening pressure is to be made uniform, the packing tightening points must be increased,
The number of tightening steps was increased and the assembling property was impaired.

Therefore, the present invention makes it possible to waterproof the electronic scale by using the common seal packing even if the case size changes depending on the weighing amount, which is economical and defective in sealing. The problem is to create a structure that does not generate

[0005]

[Means for Solving the Problems] That is, the present invention relates to an electronic scale for weighing the weight of an object to be weighed placed on a weighing pan by a load cell, and storing the load cell and an electronic circuit board connected to the load cell. A unit box and an external case in which the unit box is detachably accommodated, and a sealing means for providing a watertight structure inside the unit box is provided at a connecting portion between the external case and the unit box. Is characterized by.

[0006]

According to the above construction, the load cell, which is the main part of the weighing section of the electronic scale, and the electronic circuit board are housed in the unit box, and the unit box is attached to the outer case by the sealing means. Even if the size changes, the unit case can be attached to the outer case as it is without any change, and it is not necessary to manufacture the sealing means in accordance with the outer case each time the size of the outer case changes.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

The electronic scale 1 shown in FIG. 1 includes an outer case 2 and
A unit box 3 housed in the outer case 2,
With the weighing pan 4 as a main component and the load cell 5 and the electronic circuit board 6 connected to the load cell 5 housed in the unit case 3, the unit case 3
Has a watertight structure with respect to the outer case 2, and the weighing pan 4 is connected to the load cell 5.

That is, the outer case 2 is composed of a case body 7 of an upper opening type and a lid 8 covering the upper opening of the case body. A reinforcing plate 9 is superposed on the inner bottom portion of the case body 7, and the case is formed. A leg structure whose height is adjustable is provided to the outer case 2 by screwing a screw shaft 11 having a leg 10 from the lower side of the main body 7 through the case main body 7 and screwing it into the reinforcing plate 9.

The unit case 3 is housed in the outer case 2 by covering the case body 7 with the unit case 3 attached to the lower surface of the cover body 8. In that case, the unit case 3 is an upper opening type case similar to the case body 7, and the load cell 5 and the electronic circuit board 6 on which the electronic circuit component group is mounted are respectively supported by the support members 12 and 13. The cable 14 that is supported and built into the electronic circuit board 6 is taken out from the side surface of the unit case 3 and is drawn to the outside through the cable take-out portion 15 provided in the case body 7. In addition, at the cable take-out portion of the unit case 3, the take-out portion is waterproofed by the packing 16.

Further, a seal packing 17 is fitted around the opening of the unit case 3 around the opening of the case side wall 3a, and the connecting plate is positioned outside the rubber packing 17. 18 is fixed to the outer surface of the case side wall 3a, and in the state where the lid 8 is covered so as to cover the opening of the unit case 3, the lid 8 and the connecting plate 18 are fitted with a suitable number of screws 19 and 19. By connecting, the unit case 3 is attached to the lid body 8,
Then, as described above, the unit case 3 is housed inside the case body 7 in this state. The screws 19, 19
The above-mentioned sealing packing 17 is pressed against the lower surface of the lid body 8 by the connection by and is sealed at this portion.

A weighing pan 4 is located above the outer case 2, and a shaft portion 20 integrally suspended from the central portion of the weighing pan 4 passes through a through hole opened in the lid body 8. It projects into the unit case 3 and is connected to the rigid portion of the load cell 5 by a connecting member 21. In this case, the lower surface of the weighing pan 4 is provided with the shaft portion 20 and the ring-shaped flange portion 22 surrounding the outside of the through hole, and the mounting seat 23 surrounding the through hole is formed on the lid body 3 side. A flexible diaphragm-shaped waterproof membrane sheet 24 is stretched over the upper surface of the mounting seat 23 and the lower end of the flange portion 22. Therefore, the upper opening of the unit case 3 is shielded from the outside by the waterproof film sheet 24, so that the inside of the unit case 3 has a watertight structure.

In addition, inside the unit case 3, the pressure regulating chamber 2 surrounded by the partition wall 25 at a position close to the side portion.
6 is formed, a fine hole 27 communicating with the inside of the unit case 3 is provided in the upper portion of the pressure adjusting chamber 26, and a breathing hole 28 is provided in the lower portion, so that the unit case 3 is formed as the outer case 2
When set inside, the breathing hole 28 communicates with the outside of the outer case 2 through the communication hole 29 formed in the reinforcing plate 9 and the case body 7 described above. This breathing hole 29 is in a sealed unit case 3
It is a hole that allows air to flow in and out in order to make the internal air pressure of the device equal to the external air pressure, and has a small diameter that makes it extremely difficult for water to enter.

In the electronic balance 1 having the above-described structure, the unit case 3 containing the load cell 5 and the electronic circuit board 6 is connected to the lid 8 of the outer case 2 while being sealed by the sealing packing 17. While being accommodated in the external case 2 in this state, the weighing pan 4 and the lid 8 are provided in a portion where the shaft portion 20 of the weighing pan 4 penetrates the lid 8.
It is sealed by a waterproof film sheet 24 connected between the. Therefore, even if water is splashed on the electronic scale 1 due to the electronic scale 1 being used in a place with a lot of water, and therefore water may enter the outer case 2, the unit case Since 3 is kept in a completely watertight state, the load cell 5 and the electronic circuit board 6 do not get wet with water.

In addition, in the electronic scale 1 described above, the load cell 5 and the electronic circuit board 6 which are the main constituent elements of the weighing section are housed in the unit case 3 and detachably attached to the lid 8. There is. Therefore, there is no relation between the size of the unit case 3 and the size of the outer case 2, and even if the size of the outer case 2 is variously changed, the unit case 3 having a constant size is used regardless of the change. Can be attached to the outer case 2. Therefore, the lid 8 in the outer case 2
Only one type of packing 17 is required to control the seal of the connection between the unit case 3 and the unit case 3, and the packing packing 17 has commonality. Further, since the seal packing 17 can be used in common, even if the outer case 2 becomes large, there is no variation in tightening pressure at the seal portion, waterproof failure does not occur, and it is not necessary to increase the packing tightening point. Assemblability is improved.

By the way, depending on the place of use where there is a lot of water, it is possible that the electronic scale 1 is erroneously sunk in half or completely as shown in FIG. Then, as described above, the electronic balance 1 is provided with the breathing hole 28 for pressure balance with the external air, and this is communicated to the outside by the communication hole 29, so that the water X communicates with the communication hole 29 and breaths. It will flow into the pressure regulation chamber 26 through the hole 28. However, the pressure regulation chamber 26 is not included in the unit case 3
Is independently provided by the partition wall 25 and communicates with the inside of the unit case only through the pores 27. Therefore, the water X entering the pressure control chamber 26 causes the inside of the unit case 3 including the pressure control chamber 26. As the air is compressed, the water X stops entering when the water pressure and the air pressure are balanced, and the load cell 5 and the electronic circuit board 6 are protected.

FIG. 4 shows another embodiment of the present invention.
Instead of the pressure regulation chamber 26 in FIG. 1, the unit case 10
3, a bellows 30 is provided outside, and the bellows 30 is attached to the unit case 103 to communicate with the pores 127.
The air inside the unit case is moved in and out of the bellows 30 to balance the air pressure inside the unit case and the external air pressure. In the structure of this embodiment, FIG.
Since there is no breathing hole that communicates with the outside like the structure, it is possible to more reliably prevent water from entering when the electronic scale is submerged or completely submerged in water as described above.

As another configuration, a part of the unit case 3 may be formed of a breathable filter that allows air to escape only in the outward direction, or a desiccant may be placed inside the unit case 3 to make the unit case 3 Dehumidification inside may be promoted.

Further, a packing for sealing between the unit case 3 and the lid 8 is provided with a hollow portion 31 as shown in FIG.
When equipped with, the unit case 3 and the lid 8
This is useful because the packing 117 is well conformed to the lower surface of the lid body 8 at the time of fastening with the screws 19 to obtain a high sealing pressure, and the sealing property is further improved.

[0020]

[Effect of the device] As is clear from the above description,
According to the present invention, since the load cell, which is the main part of the weighing section of the electronic scale, and the electronic circuit board are housed in the unit box and the unit box is attached to the outer case by the sealing means, the size of the outer case is changed. However, the unit case can be attached to the outer case as it is without any change, and it is not necessary to manufacture the sealing means in accordance with the outer case each time the size of the outer case changes. Therefore, sealing means such as packing can be commonly used, which is economical, and even if the outer case becomes large, the tightening pressure of the seal portion does not vary, and reliable waterproof performance can be expected.

[Brief description of drawings]

FIG. 1 is a sectional view of an electronic scale according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is an explanatory view of a submerged state of the electronic scale.

FIG. 4 is a sectional view of another embodiment.

FIG. 5 is a sectional view of a modified example of the packing.

[Explanation of symbols]

 1 electronic scale 2 external case 3,103 unit case 4 weighing pan 5 load cell 6 electronic circuit board 17,117 seal packing

Claims (1)

(57) [Scope of utility model registration request] 1. An electronic scale for weighing the weight of an object placed on a weighing pan with a load cell, the unit box containing the load cell and an electronic circuit board connected to the load cell; An electronic scale, comprising: an external case in which the unit box is detachably accommodated, and a sealing means for providing a watertight structure inside the unit box is provided at a connecting portion between the external case and the unit box.