JP6794049B2 - Truck scale - Google Patents

Description

The present invention relates to a truck scale using a load cell Le used as a load detector.

The load cell may be used as a load detector for various load detectors, for example, a load detector for a tank or a hopper for storing various articles such as liquids and solids. In such a case, for example, Patent Document 1 describes. As shown above, the load of the tank or hopper is applied to the load receiving portion of the load cell via the mounting bracket fixed to the bottom surface of the tank or hopper.

Japanese Unexamined Patent Publication No. 2014-163877

Hot and cold articles are stored in the tank and hopper, and the temperature of the tank and hopper may fluctuate depending on the temperature of the stored articles.

As described above, the load receiving portion of the load cell is attached to the bottom surface of the tank, hopper, etc. via a metal mounting bracket having high thermal conductivity, so that the load cell is affected by temperature fluctuations of the tank or hopper. Will receive.

Since the Young's modulus of the strain-causing body constituting the load cell and the resistance value of the strain gauge attached to the strain-generating body change due to the temperature fluctuation of the load cell, the measurement accuracy is lowered due to the influence of the temperature fluctuation. It will be.

The present invention has been made in view of the above points, and an object of the present invention is to suppress a decrease in measurement accuracy of a load cell due to temperature fluctuation.

In order to achieve the above object, the present invention is configured as follows.

(1) The truck scale of the present invention is a truck scale in which a platform on which a vehicle is mounted and a plurality of load cells supporting the platform are incorporated in a pit.
The load cell is arranged between the metal support member on the table side and the metal support member on the pit side, and the strain-causing body of the load cell is columnar and the upper end of the strain-causing body. The portion and the lower end portion receive a load from the support member on the front-end table side and the pit side, and between the upper end portion and the support member on the front-end table side, and between the lower end portion and the pit side. A load receiving metal fitting made of a metal material and a heat insulating material are interposed between the support member and the heat insulating material in a state where the heat insulating material is sandwiched between the support member and the load receiving metal fitting made of the metal material .

According to the track scale of the present invention, the upper end and the lower end of the strain-causing body are insulated with a load receiving metal fitting made of a metal material and a heat insulating material between the support members on the mounting side and the pit side. Since the material is interposed in a state of being sandwiched between the load receiving metal fitting made of the metal material and the metal supporting member, the strain generating body is interposed via the load receiving metal fitting made of the metal material and the metal supporting member. While the load is stably applied, the influence of the temperature difference between the upper and lower support members on the strain generating body can be suppressed by the heat insulating material sandwiched between them. For example, it is possible to reduce the influence of the temperature fluctuation of the support member on the mount side, which rises due to the heat from the engine of the vehicle that is placed on the mount, on the strain-causing body, thereby weighing the load cell. It is possible to suppress a decrease in accuracy.

( 2 ) In another embodiment of the truck scale of the present invention, the strain generating body, the load receiving metal fitting made of the metal material, and the support member are made of the same metal material.

According to this embodiment, since the strain generating body, the load receiving metal fitting made of the metal material, and the support member are made of the same metal material, the load receiving metal fitting made of the metal material is made by the load applied to the strain generating body. The load from the upper and lower support members is stably applied to the strain generating body without the support member being deformed.

( 3 ) In still another embodiment of the truck scale of the present invention, the heat insulating material is a resin material.

According to this embodiment, heat insulation can be efficiently performed by using a resin material having a low thermal conductivity as a heat insulating material.

According to the track scale of the present invention, the upper end and the lower end of the strain-causing body are insulated with a load receiving metal fitting made of a metal material and a heat insulating material between the support members on the mounting side and the pit side. Since the material is interposed in a state of being sandwiched between the load receiving metal fitting made of the metal material and the metal supporting member, the strain generating body is interposed via the load receiving metal fitting made of the metal material and the metal supporting member. While the load is stably applied, the influence of the temperature difference between the upper and lower support members on the strain generating body can be suppressed by the heat insulating material sandwiched between them.

FIG. 1 is a plan view of a truck scale installed according to an embodiment of the present invention. FIG. 2 is a vertical sectional side view of one corner of FIG. FIG. 3 is an enlarged partial cross-sectional view of FIG. FIG. 4 is a block diagram of the track scale of FIG. FIG. 5 is a schematic diagram of a combination scale as a reference example . FIG. 6 is a diagram showing a load cell mounting structure as a reference example .

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view showing an installed state of a truck scale according to an embodiment of the present invention, and FIG. 2 is a vertical sectional side view of one corner portion thereof.

The truck scale 1 of this embodiment has a rectangular mounting 2 on which a vehicle such as a truck enters and is mounted, and a plurality of places below the mounting 2, in this example, four corners, respectively. This is a pit-type truck scale in which four supporting load cells 3 are incorporated into a concrete pit 5 formed by digging down the ground surface 4.

The concrete pit 5 is formed by digging the ground surface 4 so that the upper surface of the mount 2 is at the same height as the ground surface 4, and is a compression type pit 5 between the steel mount 2 and the pit 5. Each load cell 3 is installed. Each load cell 3 supports the mount 2 in an upright state, and a load corresponding to the weight of the vehicle approaching and mounted on the mount 2 is distributed and applied to each load cell 3.

A necessary gap is secured between the outer surface 2a, which is the outer peripheral portion of the mounting table 2, and the inner wall 5a of the pit 5 so that the mounting table 2 does not come into contact with each other under normal shaking motion.

In this embodiment, the load cell 3 is attached between the mount 2 and the pit 5 as follows in order to suppress a decrease in the measurement accuracy of the load cell 3 due to temperature fluctuation.

That is, as shown in FIG. 2, each load cell 3 has an upper support metal fitting 20 as a support member attached to the mount 2 and a lower support metal fitting 21 as a support member attached to the bottom surface of the pit 5. Placed in between.

Further, an upper load receiving metal fitting 24 made of an upper heat insulating material 22 and a metal material is interposed between the plate-shaped upper support metal fitting 20 and the upper end portion of the load cell 3, and the plate-shaped lower support metal fitting 21 and the load cell 3 are interposed. A lower heat insulating material 23 and a lower load receiving metal fitting 25 made of a metal material are interposed between the lower end portion of the above.

FIG. 3 is an enlarged partial cross-sectional view of FIG.

The load cell 3 of this embodiment is a compression type load cell having a substantially columnar strain-causing body 30. The strain generating body 30 is made of a metal such as an aluminum alloy or stainless steel. The strain-causing body 30 has a central portion in the longitudinal direction as a strain-causing portion 31 in which strain is generated by a load, and the strain-causing portion 31 has a plurality of strains (not shown) that detect compression strain and extension strain, respectively. A gauge is attached. The plurality of strain gauges form a bridge circuit and output an analog load signal corresponding to the load applied to the strain generating body 30.

The upper and lower end portions 32 and 33 of the strain generating body 30 are formed to be thicker than the strain generating portion 31, and the end surface surfaces 34 and 35 thereof protrude in a curved surface shape. The strain-causing body 30 is covered with a metal case 36 with the upper and lower end portions 32 and 33 exposed to the outside.

The load cell 3 including the strain generating body 30 is attached so that the strain generating body 30 is in an upright state, that is, the central axis of the strain generating body 30 extends in the vertical direction. At this time, the upper end surface 34 of the strain generating body 30 comes into contact with the upper load receiving surface 24a of the columnar upper load receiving metal fitting 24 corresponding to the load cell 3. Further, the lower end surface 35 of the strain generating body 30 comes into contact with the lower load receiving surface 25a of the columnar lower load receiving metal fitting 25 corresponding to the load cell 3. Specifically, the upper load receiving surface 24a of the upper load receiving metal fitting 24 is a horizontal flat surface, and the center of the upper end surface 34 of the strain generating body 30 makes point contact with the upper load receiving surface 24a. Further, the lower load receiving surface 25a of the lower load receiving metal fitting 25 is also a horizontal flat surface, and the center of the lower end surface 35 of the strain generating body 30 makes point contact with the lower load receiving surface 25a.

Around the upper load receiving surface 24a and the lower load receiving surface 25a, wall portions 24b and 25b projecting downward and upward are formed so that the strain generating body 30 does not shift.

A disk-shaped upper heat insulating material 22 is interposed between the upper load receiving metal fitting 24 and the upper supporting metal fitting 20, and a disk-shaped upper heat insulating material 22 is interposed between the lower load receiving metal fitting 25 and the lower supporting metal fitting 21. A lower heat insulating material 23 is interposed.

The upper and lower heat insulating materials 22 and 23 are made of a resin having a low thermal conductivity, for example, bakelite.

In this embodiment, the upper heat insulating material 22 is interposed between the upper support metal fitting 20 and the upper end surface 34 of the load cell 3 while being sandwiched between the upper support metal fitting 20 and the upper load receiving metal fitting 24. The lower heat insulating material 23 is interposed between the lower support metal fitting 21 and the lower end surface 35 of the load cell 3 in a state of being sandwiched between the lower support metal fitting 21 and the lower load receiving metal fitting 25, that is, An upper heat insulating material 22 is interposed between the upper end surface 34 of the load cell 3 and the mount 2, and a lower heat insulating material 23 is interposed between the lower end surface 35 of the load cell 3 and the bottom surface of the pit 5. ..

As a result, the load cell 3 can suppress heat transfer from above and below, and is not affected by the temperature difference between the mounting table 2 and the bottom surface of the pit 5, and is placed on the mounting table 2, for example. The heat from the engine of the vehicle is not affected by the temperature fluctuation of the mount 2 whose temperature rises, and it is possible to suppress the deterioration of the measurement accuracy of the load cell 3.

Further, the upper heat insulating material 22 is sandwiched by the planes of the metal upper support metal fitting 20 and the upper load receiving metal fitting 24, and the lower heat insulating material 23 is sandwiched between the metal lower support metal fitting 21 and the metal lower support metal fitting 21. Since it is sandwiched between the flat surfaces of the lower load receiving metal fitting 25, the loads from the upper and lower support metal fittings 20 and 21 are stably applied to the load cell 3 with the strain generating body 30 upright.

Further, in this embodiment, the upper and lower support metal fittings 20 and 21 and the upper and lower load receiving metal fittings 24 and 25 are made of the same metal material as the strain generating body 30 of the load cell 3, and the support metal fittings 20 and 21 and the load receiving metal fittings 20 and 21 and the load receiving metal fittings 20 and 21 are made of the same metal material. A load is applied to the strain generating body 30 without deforming the metal fittings 24 and 25.

In this embodiment, the upper and lower load receiving metal fittings 24 and 25 and the upper and lower heat insulating materials 22 and 23 are separate members, but the upper and lower load receiving metal fittings 24 and 25 are easy to handle. And the upper and lower heat insulating materials 22, 23 may be joined and integrated with an adhesive or the like, respectively.

FIG. 4 is a block diagram of the track scale 1 of this embodiment.

The track scale 1 of this embodiment includes the above-mentioned load cells 3 and an indicator 8 to which each load cell 3 is connected.

As described above, each load cell 3 outputs an analog load signal corresponding to the applied load from the bridge circuit.

The indicator 8 is the weight of the vehicle on the platform 2 based on the A / D converter 10 that A / D converts the analog load signal from each load cell 3 and the digital load signal from the A / D converter 10. It is provided with a microcomputer 11 for calculating the above, an operation input unit 12 having operation keys for performing various setting inputs, and a display unit 13 for displaying the measured weight value and the like.

As described above, in the present embodiment, the compression type load cell 3 arranged between the mount 2 and the pit 5 includes the upper and lower ends 32 and 33 of the strain generating body 30 and the upper and lower support metal fittings 20 and 21. Since the upper and lower heat insulating materials 22 and 23 are interposed between them, the heat transfer from the upper and lower sides to the strain generating body 30 can be suppressed by the heat insulating materials 22 and 23, thereby mounting the stand. The influence of the temperature difference between 2 and the bottom surface of the pit 5 on the strain generating body can be reduced, and the deterioration of the weighing accuracy due to the temperature fluctuation of the load cell 3 can be suppressed.

Further, since the upper and lower heat insulating materials 22 and 23 are interposed in a state of being sandwiched between the flat upper and lower support metal fittings 20 and 21 and the flat surfaces of the upper and lower load receiving metal fittings 24 and 25, the upper and lower support metal fittings 22 and 23 are interposed. The loads from 20 and 21 are stably applied to the strain generating body 30 in an upright state.

FIG. 5 is a schematic schematic diagram of a combination scale as a reference example.

As shown in the schematic schematic diagram of FIG. 5, the combination scale is provided with a conical dispersion feeder 40 in the center of the upper part, which radially disperses the articles to be measured supplied from an external supply device by vibration. Around the feeder 40, a linear feeder 42 is provided for feeding the articles sent from the distributed feeder 40 to each supply hopper 41 by vibration. A plurality of supply hoppers 41 and measuring hoppers 43 are provided correspondingly below the end of the linear feeder 42, and are arranged in a circular shape around the distributed feeder 40. Further, each weighing hopper 43 is supported by a load cell 44 that measures the weight of an article in the weighing hopper 43, and the weight is measured by the load cell 44. A collecting chute 45 is arranged below the measuring hopper 43, and articles discharged from the measuring hopper 43 are collected and discharged downward via the collecting hopper 46. For example, a wrapping machine is arranged below the combination scale, and the articles discharged from the collecting hopper 46 are put into the inlet of the wrapping machine.

In the combination scale, the combination calculation is performed by a control unit (not shown). In this combination calculation, the optimum combination of weighing hoppers 43 whose total weight value (combination weight value), which is a combination of various weight values of articles of a plurality of weighing hoppers 43, is within an allowable range with respect to the target combination weight value is selected. , The article is discharged from the selected weighing hopper 43, and is put into the packaging machine via the collecting hopper 46 for packaging.

FIG. 6 is a schematic view showing an attached state of the load cell 44 in this combination scale.

The load cell 44 of this reference example includes a strain generating body 47, and the strain generating body 47 has a pair of upper and lower parallel beams 47a and 47b connected at both ends, one end having a fixed end 47c and the other end having a fixed end 47c. It is a parallelogram type (roversal type) load cell having a movable end portion 47d.

The end surface of the fixed end portion 47c of the strain generating body 47 is fixedly connected to the load cell support metal fitting 50 via the fixed side metal material 48 and the fixed side heat insulating material 49 by screws. Further, the end surface of the movable end portion 47d of the strain generating body 47 is fixedly connected to the L-shaped measuring hopper support metal fitting 53 via the movable side metal material 51 and the movable side heat insulating material 52 by screws. A measuring hopper 43 is connected and supported on the measuring hopper support metal fitting 53.

As a result, the weight of the measuring hopper 43 is loaded on the strain generating body 47, and the weight is measured.

In this reference example , since the heat insulating materials 49 and 52 are interposed on the fixed end portion 47c side and the movable end portion 47d side of the strain generating body 47, respectively, heat transfer to the strain generating body 47 is suppressed. .. As a result, when a low-temperature article such as frozen food or a high-temperature article such as hot corn is supplied to the weighing hopper 43 and weighed, heat from the low-temperature or high-temperature article is generated. Transmission to the strain generating body 47 via the measuring hopper support metal fitting 53 or the like is suppressed by the heat insulating material 51. Further, heat from the combination scale main body side, for example, heat generated from the drive unit that opens and closes the discharge gates of the hoppers 41 and 43 and the drive unit that vibrates the feeders 40 and 42, is generated via the load cell support bracket 50 and the like. The transmission to the strain generating body 47 is suppressed by the heat insulating material 49.

In this way, the heat transfer to both ends 47c and 47d of the strain generating body 47 of the load cell 44 is suppressed, so that the load cell 44 is less susceptible to temperature fluctuations due to the temperature of the article supplied to the measuring hopper 43, for example. It is possible to suppress a decrease in the measurement accuracy of the load cell 44 due to temperature fluctuation.

1 Track scale 2 Platform 3,44 Load cell 5 Pit 8 Indicator 20 Upper support bracket (support member)
21 Lower support bracket (support member)
22 Upper heat insulating material 23 Lower heat insulating material 24 Upper load receiving metal fittings
25 Lower load receiving bracket
30,47 Distorted body

Claims (3)

The platform on which the vehicle is mounted and the plurality of load cells that support the platform are truck scales built into the pit.
The load cell is arranged between the metal support member on the table side and the metal support member on the pit side.
The strain-causing body of the load cell is columnar and receives a load on the upper end and the lower end of the strain-causing body from the support members on the table side and the pit side described above.
Between the upper end portion and the support member on the above-mentioned stand side, and between the lower end portion and the support member on the pit side, a load receiving metal fitting and a heat insulating material made of a metal material provide the heat insulating material. Intervening in a state of being sandwiched between the support member and the load receiving metal fitting made of the metal material.
A track scale that features that. The strain-generating body, the load receiving metal fitting made of the metal material, and the support member are made of the same metal material.
The track scale according to claim 1. The track scale according to claim 1 or 2, wherein the heat insulating material is a resin material.

Images