JPH0421080Y2 - - Google Patents

Description

[Detailed description of the invention] "Field of industrial application" This invention relates to a rail load cell used to detect the weight of an object to be weighed suspended from a pulley with a hook, and in particular, to simplify the installation work. This invention relates to a rail load cell that improves measurement accuracy.

"Prior Art" For example, trolley conveyors are widely used in slaughterhouses to transport relatively large chunks of meat. This trolley conveyor is composed of a built-in rail and a pulley with a hook that is movably provided on the rail, and is adapted to move the meat by suspending it from the hook. Such a trolley conveyor is provided with a weighing device called a trolley scale to measure the weight of the meat loaves suspended from the hooks. As shown in Figure 5 A and B, this trolley scale is installed on a horizontally installed beam 1.
A load detector 2 composed of a load cell with a strain gauge attached to a strain body is provided, a rail 3 is arranged parallel to the lower part of the beam 1, and a part of the rail 3 is connected to a weighing rail. Replaced with 4,
The load applied to the weighing rail 4 is transmitted to the load detector 2 via a pair of load transmitting members 5, 5. Then, the hooked pulley 6 on which the meat lump is suspended is moved onto the weighing rail 4 to measure the weight of the meat lump.

"Problems to be Solved by the Invention" By the way, although the conventional trolley scale described above achieves relatively high precision weight measurement, it also has the following drawbacks.

Since the load detector 2 must be attached to the beam 1 above the rail 3, the installation equipment becomes large-scale.

When installing, it is necessary to perform position adjustment in order to match the heights of the metering rail 4 and the rail 3, and this position adjustment is complicated.

There are many parts and the manufacturing cost is high.

In order to eliminate such drawbacks, for example,
As shown in FIG. 6A, a trolley scale in which part of the rail 3 is replaced with a rail load cell 8 can be considered. In this figure, the rail load cell 8 includes a pair of fixed parts 8a, 8a fixed to each end of the rails 3, 3, a pair of strain-generating parts 8b, 8b, each having a circular hole 9 formed therein. Strain parts 8b, 8
It consists of a movable part 8c which interconnects the parts 8a and 8b and which is displaced downward by a load applied from above, and a strain gauge 10 attached to each circular hole 9, respectively. However, the configuration in which the rail load cell 8 having the above-described structure is fixed between the rails 3 leads to a decrease in measurement accuracy, so it has been necessary to improve the structure of the rail load cell 8. That is, as shown in FIG. 6B, the movable part 8c
When a downward load F is applied via the pulley 6 to
The movable part 8c is displaced downward and each strain generating part 8b, 8b
Distortion occurs in each of the fixed parts 8a,
8a is Δl toward the center of the rail load cell 8
Try to displace it gradually. However, each fixed part 8a,
8a are each fixed to the rail 3 and movement in the horizontal direction is restricted, so the strain-generating parts 8b, 8b have
In addition to the downward load, a tensile force H acts on each of them as shown in the figure, and as a result, the amount of strain in the strain-generating portions 8b, 8b no longer corresponds to the load F, resulting in a decrease in measurement accuracy. Furthermore, if the tensile force H acts repeatedly every time measurement is performed, no matter how strong the mechanical fastening between the fixing parts 8a, 8a and the rails 3, 3,
A slight deviation occurs between them, and the internal stress constantly changes, which impairs the reproducibility of load detection, and this also reduces measurement accuracy.

The present invention has been made in view of the above-mentioned circumstances, and aims to provide a rail load cell that not only simplifies installation work but also improves measurement accuracy.

``Means for Solving the Problems'' The present invention consists of a fixed part fixed to each end of a rail that guides a pulley with a hook that suspends an object to be weighed at both ends, and a pair of thin walled parts attached to the fixed part. a movable part supported so as to be freely displaceable in the vertical direction via a connecting part and having a guide surface for guiding the pulley at an upper end; Accordingly, a pair of swinging parts each vertically swinging around each of the connecting parts, and a thin strain-generating part interconnecting each other end of the pair of swinging parts are integrally constructed, and the A strain gauge is attached to the strain generating part.

"Operation" In the above configuration, when the pulley is positioned on the movable part, the movable part is displaced downward by an amount corresponding to the weight of the object to be weighed suspended from the hook of the pulley, and a pair of oscillators are accordingly moved. The other ends of the moving parts are each displaced downward around each connecting part, and this causes a strain in the strain generating part corresponding to the weight of the object to be weighed, and this strain is applied by the strain gauge. The object to be weighed is detected and the weight of the object to be weighed is measured.

"Embodiments" Hereinafter, embodiments of the present invention will be described based on the drawings.

FIGS. 1A, 1B, and 1C are diagrams showing the configuration of a first embodiment of the present invention. In these figures, 15 is a rail load cell provided between each end of the rails 3,3. In this rail load cell 15, a connecting plate 16 (see FIG. 1 C), a falling-off prevention plate 17,
This is a fixed part fixed using bolts 18 and nuts 19. A pulley 6 is provided at the upper end of this fixed part 15a.
Guide surfaces 15a ₁ and 15a ₂ for guiding are formed. Further, a movable part 15d is supported by the fixed part 15a through thin connecting parts 15b ₁ , 15c ₁ and 15b ₂ , 15c ₂ so as to be freely displaceable in the vertical direction.
A guide surface 15d 1 is formed at the upper end of the movable portion 15d to guide the pulley 6. The guide surface _15d1 has a slightly V-shaped depression in the center. On the other hand, 15e ₁ and 15e ₂ are swinging parts each having one end connected to the connecting parts 15b ₁ , 15c ₁ and 15b ₂ , 15c ₂ , and as the movable part 15d moves up and down, each connecting part Each other end swings up and down centering on 15b ₁ and 15b ₂ . Between the other ends of these swinging parts 15e ₁ and 15e ₂ is a thin strain-generating part 15.
The fixing portion 15a, the connecting portions 15b ₁ , 15c ₁ , 15b ₂ , and
15c ₂ , movable part 15d, swinging part 15e ₁ , 15e ₂ ,
All of the strain generating parts 15f are integrally constructed. In addition, strain gauges 10, 10 are provided in the strain generating portion 15f.
is pasted thereon, thereby configuring the rail load cell 15. Here, the falling-off prevention plate 17 includes connecting portions 15b ₁ , 15c ₁ , 15b ₂ , 15
c ₂ , the movable part 15d, and the swinging part 15e ₁ , 1
It is designed to cover a part of 5e ₂ from the side,
This prevents the movable portion 15d and the pulley 6 from falling off when the connecting portions 15b ₁ , 15c ₁ , 15b ₂ , 15c ₂ are broken.

In the above configuration, as shown in Figure 1B,
When the pulley 6 is positioned on the movable part 15d, the movable part 15d is displaced downward by an amount corresponding to the weight of the object to be weighed suspended from the hook of the pulley 6, and along with this, the pair of swinging parts 15e ₁ and 15e ₂ are respectively displaced downward around the connecting portions 15b ₁ and 15b ₂ , thereby causing a strain in the strain generating portion 15f in an amount corresponding to the weight of the object to be weighed. This strain is detected by the strain gauges 10, 10, and the weight of the object to be weighed is measured. In this case, the connecting part 15
The points A ₁ and A _{2 of b 1 and 15b 2 serve as} fulcrums, the points B ₁ and B ₂ of connecting portions 15c ₁ and 15c ₂ serve as important points, and the point C of strain-generating portion 15f serves as a point of action. Each part operates on the principle of leverage.

According to the above-described configuration, the pair of swinging parts 15e ₁ ,
In addition to bending deformation, the strain-generating portion 15f also undergoes deformation due to a horizontal tensile force due to the rocking motion of the strain gauge _15e2 . However, by combining each strain gauge 10 with a Wheatstone bridge, the horizontal direction The influence of deformation caused by tensile force is removed, and the strain-generating portion 15f always produces a strain in an amount that accurately corresponds to the object to be weighed.
are integrally constructed so that they are not easily deformed due to their lower portions, so the horizontal tensile force does not have any effect on the mounting surfaces of each fixed part 15a and the rail 3, thereby improving measurement accuracy. is planned.
Moreover, since the rail load cell 15 can be attached to the rail 3 with bolts 18 and nuts 19, installation work can be simplified. Furthermore, since the falling-off prevention plate 17 is provided, safety during weighing work can be ensured.

Note that the cross-sectional shape of the rail load cell 15 is
As shown in FIG. A, the connecting portions 15b ₁ , 15c ₁ , 15b ₂ , 15c ₂ may be configured to be thick except for the upper end portions so that twisting or breakage is less likely to occur. In addition, as _shown in FIG.
5d ₁ may be provided with a wear prevention member 20.

Next, regarding the second embodiment of the present invention, FIG.
This will be explained with reference to b. This figure differs from the first embodiment described above in that the connecting portions 15b ₁ and 15c ₁
A reinforcing part 15g ₁ extending vertically from between to the lower part of the fixed part 15a, and a reinforcing plate 15g 2 extending vertically from between the connecting parts _{15b 2} and 15c ₂ to the lower part of the fixed part 15a are provided. , connecting part 15
b ₁ and 15b ₂ from twisting, and among the guide surfaces 15a ₁ and 15a ₂ at the upper end of the fixed part 15, the guide surface on the side of the movement direction of the pulley 6 (in the direction of the arrow shown in FIG. 3B) 15a ₁ is a slope, and the pulley 6 is the movable part 15d
This makes it possible to move smoothly from one place to another.

Next, regarding the third embodiment of the present invention, FIG.
This will be explained with reference to b. The difference in this figure from the first embodiment described above is that the connecting portions 15b ₁ , 15
One pair each of c ₁ , 15b ₂ , and 15c ₂ is provided at the top and bottom,
The pair of connecting portions 15b ₁ , 15b ₁ , 15c ₁ , 15c ₁ and the pair of connecting portions 15b ₂ , 15b ₂ , 15c ₂ , 15c ₂ each constitute a roberval mechanism;
This is because the strain-generating portion 15f is constructed by forming a circular hole _15f1 . Also, in the figure, 15d ₂
and 15a ₃ are notches formed to facilitate attachment of the strain gauge 10.

"Effects of the Invention" As explained above, according to the present invention, there is a fixed part fixed to each end of the rail that guides a pulley with a hook that suspends an object to be weighed, and A movable part is supported so as to be vertically displaceable via a pair of thin connecting parts, and has a guide surface at its upper end that guides the pulley; A pair of swinging parts each vertically swinging around the respective connecting parts as the parts are displaced, and a thin strain-generating part interconnecting each other end of the pair of swinging parts are integrated. Since the strain gauge is attached to the strain generating part, the installation work is simplified, and the swinging movement of the pair of swinging parts during measurement does not affect the fixed part fixed to the rail. Therefore, an amount of strain that accurately corresponds to the weight of the object to be weighed is always generated in the strain-generating portion, and as a result, it is possible to improve measurement accuracy.

[Brief explanation of the drawing]

Figures 1A and 2B are front views showing the configuration of the first embodiment of the present invention, Figure 1C is a partial plan view showing the configuration of the same embodiment, and Figures 2A and 2B are modifications of the same embodiment. 3A and 3B are both front views showing the structure of the second embodiment of the present invention, and FIGS. 4A and 4B are both front views showing the structure of the third embodiment of the present invention. Figures 5A and 5B are a sectional view and a front view showing the configuration of a conventional trolley scale, and Figures 6A and 6B are front views showing the configuration of a conventional rail load cell. 10...Strain gauge, 15...Rail load cell, 15a...Fixed part, 15a ₁ , 15a ₂ ...
Guide surface, 15b ₁ , 15c ₁ , 15b ₂ , 15c ₂ ... Connecting part, 15d ... Movable part, 15d ₁ ... Guide surface, 1
5e ₁ , 15e ₂ ... Swinging section, 15f ... Strain-generating section.

Claims (1)

[Scope of utility model registration request] In a rail load cell that is replaced by a part of a rail that guides a pulley with a hook that suspends an object to be weighed, and that detects the load of the object to be weighed applied via the pulley, both ends are attached to each end of the rail. a fixed part that is fixed to each part; a movable part that is supported by the fixed part so as to be vertically displaceable through a pair of thin connecting parts and has a guide surface at its upper end that guides the pulley; and one end that connects the pair of parts. a pair of swinging parts that are connected to the respective parts and swing up and down about the respective connecting parts as the movable part moves up and down; A rail load cell comprising: a thin strain-generating portion connected to the strain-generating portion; and a strain gauge affixed to the strain-generating portion.