JPH08233644A - Load cell protector - Google Patents

Abstract

PURPOSE: To provide a load cell protector which effectively protects the load cell by substantially minimizing deformation to vertical load, substantially enlarging relative displacement and relative inclination in the horizontal direction of top/bottom attachment plates (plate members), and drastically improving load cell operation accuracy. CONSTITUTION: In a load cell protector 6 which is interposed between a load cell 2 and a load receiving member 3 or an installation base 1, two plate members 7, 8 which are approximately parallel to each other as fixing members are opposed to each other, a rod projection 9 is provided in the central part of the inside face of one plate member 7, a cylindrical projection 10 which encircles the rod projection 9 is provided in the inside of the opposed other plate member 8, and the opposed faces of these plate members 7, 8 are mutually connected by an elastic body 11 which is enclosed respective projections 9, 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load cell protector for a load cell using a load cell, which is applied to a platform scale, a material supply hopper, a compression / tensile tester and the like. The operating accuracy of the dosels is sufficiently enhanced and the rod cells are effectively protected against external forces in the horizontal direction and the tilting direction.

[0002]

2. Description of the Related Art As a conventional platform scale applied to the weight measurement of a truck, for example, as shown in a plan view of FIG.
A load receiving member 100 having a rectangular shape that allows the entire truck to be loaded is provided at least at each corner of the load cell 10.
There is one attached to the installation base 102 via 1,
Here, a load cell protection member 103 is arranged between the load receiving member 100 and the load cell 101.

FIG. 6 shows a conventional load cell protection member 103.
Is a front view showing a mounting state of a plurality of elastic layers 103a made of rubber or a rubber-like elastic body, and a plurality of rigid plates 103b made of a metal plate or the like. Face plates 103c and 103d on the end faces
The lower surface plate 103d of the load cell protection member 103, which is fixedly attached to the load cell 101, is bolted to the pressure receiving portion 101a of the load cell 101, and the upper surface plate 103c is connected to the load receiving member 1.
The lower cell 100a of No. 00 is mounted with the load cell protection member 103 by also bolting it.

7 (a) and 7 (b) are a plan view and a front view showing a load cell protection member 203 as another conventional example. In this case, upper and lower face plates 203c, 203 are provided.
Elastic layer 20 made of rubber or a rubber-like elastic body between d
3a is vulcanized and bonded. The elastic layer 203a is formed into a disc shape, and is considered so as to obtain mechanical characteristics (for example, compression rigidity and bending rigidity) that are substantially symmetrical in each direction with respect to the center of the disk. And the elastic layer 2
A circular cylinder 203e provided at the center of a lower plate 203d having a disk shape substantially the same as that of 03a is connected to the load cell 201.
Cylindrical hole 20 provided in the central portion of the pressure receiving portion 201a of
1b, and the rectangular upper plate 203c,
The load cell protection member 203 is fixed to the lower frame (not shown) of the load receiving member 100 by bolting.
Is attached. The bottom surface of the pressure receiving portion 201a is located above the bottom surface of the frame-shaped fixing portion 204 of the load cell 201, and the pressure receiving portion 201a is located between the pressure receiving portion 201a and the frame-shaped fixing portion 204. A plurality of beam members 205 arranged around the above are fixed, and strain gauges 206 are fixed to the upper and lower surfaces of each beam member 205 by adhesion or the like. Therefore, the load receiving member 100
The vertical load transmitted from the load cell protection member 203
The pressure receiving portion 201a is pushed down via the and the beam member 205 is bent to change the resistance value of the strain gauge 206.

Such a load cell protection member 103 or 2
03 is a load cell 101 or 20 with a small amount of deformation with respect to a vertical load acting on the load receiving member 100.
1 accurately transmits the vertical load to the load receiving member 10
The levelness of 0 is increased to sufficiently prevent the inclination of the track on the load receiving member, and the load cell 101 or 201 is effectively protected by being largely deformed against an external force in the horizontal direction. In addition, the operation accuracy of the load cell 101 or 201 is improved, and at the same time, the heat shrinkage of each part and the formation error of the mounting hole are absorbed, and the tilt displacement of the other face plate with respect to one face plate is sufficiently large. This also protects the load cell 101 or 201 and improves the operation accuracy, and also functions to absorb the inclination of the protective member mounting surface of the load cell and / or the load receiving member 100. Is preferred.

[0006]

However, the above-mentioned conventional load cell protection member 103 or 203 has a disadvantage that it is not possible to sufficiently balance such functions. That is, the load cell protection member 103
The horizontal deformation amount of 203 or 203 increases as the total rubber thickness increases, and in the case of the load cell protection member 103, even if the total rubber thickness is the same, the vertical deformation amount increases as the number of laminated rigid plates increases. Can be smaller, while lower
In the case of the decel protection member 203, the vertical deformation amount can be made smaller as the thickness of the elastic layer 203a is reduced, whereby a large horizontal deformation amount can be secured under a small vertical deformation amount. Although it can be done, as it is, the upper and lower face plates 103c, 103d and 203c, 2
It is not possible to secure a large relative tilt amount of 03d. On the other hand, when a large relative tilt amount is secured by increasing the rubber thickness, there is a problem that the vertical deformation amount also becomes large. It was

The present invention has been made as a result of studies aimed at solving such problems of the prior art, and an object of the present invention is to sufficiently reduce the amount of deformation with respect to a vertical load. Make the displacement in the horizontal direction and the amount of relative tilt of the upper and lower plates sufficiently large,
The load cell operating accuracy is greatly improved and
It is an object of the present invention to provide a load cell protection device capable of effectively protecting the dosels against a large external force in an unintended direction.

[0008]

In order to achieve the above object, the load cell protection device of the present invention is defined in claim 1.
As described in 1), between the load cell and the load receiving member of the load cell including the load cell and the load receiving member sequentially arranged on the installation base, or between the load mounting base and the load base. A load cell protection device interposed between two plate-shaped members that are substantially parallel to each other, and a bar-shaped projection is provided at the center of the inner surface of one plate-shaped member, and Cylindrical projections that are arranged concentrically outside the rod-shaped projections are provided on the inner surface of the plate-shaped member, and the facing surfaces of these plate-shaped members are provided by an elastic body that includes the projections provided on the facing surface. They are interconnected.

Further, the arrangement of the rod-shaped projection and the cylindrical projection opposite to each other is as described in claim 1 as described in claim 2 in order to prevent the allowable displacement in each direction from becoming excessive. In the load cell protection device described above, it is preferable that the leading end portion of the rod-shaped projection is arranged in the cylinder of the cylindrical projection.

Further, in order to make the deformation of the elastic body sandwiched between the pair of plate-shaped members into a more preferable state depending on the direction of the external force, as described in claim 3, claim 1 Alternatively, in the load cell protection device described in item 2, the distance between the outer peripheral surface of the rod-shaped projection and the inner peripheral surface of the tubular projection is between the tip surface of the tubular projection and the inner surface of the plate-shaped member. It is set so that it is not narrower than the interval.

[0011]

In this load cell protection device, the compressive deformation of the load cell under the action of the vertical load causes the inner surface of the plate-like member to be separated by the projections provided on each of the two plate-like members which are substantially parallel to each other. Since the deformation of the elastic body sandwiched between the tip surfaces of the protrusions is effectively restrained and effectively prevented, the vertical load is absorbed by the load cell protection device. Instead, it will be accurately transmitted to the load cell.

Further, when the external force in the horizontal direction is applied to the protective device, the elastic members between the upper and lower plate-shaped members are provided with rod-shaped projections at the central portion of the upper plate-shaped member, and the rod-shaped projections are provided outside the elastic members. Since the deformation of the lower plate member is appropriately suppressed by the configuration of the present invention in which the cylindrical projections are arranged, it can be sufficiently deformed in the horizontal direction (shear deformation), so that it is necessary in the acting direction of the external force. Therefore, it is possible to make a sufficient relative displacement.

With respect to the action of the external force in the direction in which the plate members are tilted relative to each other, the deformations in the tilting direction are appropriately suppressed by the respective projections provided on the plate members. With the rod-shaped protrusion provided in the center of the plate-shaped member as a fulcrum, the elastic bodies arranged on the outer peripheral portion of the cylindrical protrusion provided on the other plate-shaped member are expanded and compressed on both sides of the cylindrical protrusion, respectively. By deforming, both plate members can be largely tilted relative to each other.

Therefore, it is possible to sufficiently prevent the load cell from receiving a large external force in an unintended direction by each of these external forces, thereby enhancing the operation accuracy (measurement accuracy) of the load cell, and at the same time, The load cell can be effectively protected.

Here, the load cell protection device of the present invention is
In order to further enhance the function and effect of the cylindrical projection, the rod-shaped projection and the cylindrical projection are extended in the direction of the facing plate-like member so that the cylindrical projection is formed. By forming the tip of the rod-shaped projection to enter the cylinder, the amount of the shear deformation in the case of receiving an external force in the horizontal direction, or the case of receiving an external force in the direction of relative tilting of both plate-like members It is possible to more effectively control the amount of relative tilt deformation of, and to set limits on those amounts. That is, the excessive shear deformation restricts the amount of shear deformation such that the tip portions of the rod-shaped projection and the cylindrical projection come into contact with each other via the elastic body. In the case of tilting deformation, the amount of tilting is restricted by the state in which one end of the cylindrical projection tilted relative to the rod-shaped projection as a fulcrum abuts the inner surface of the opposing plate-shaped member via an elastic body. It
Furthermore, since the tips of both protrusions are extended in this way, the tip surfaces of the respective projections approach the inner surface of the plate-shaped member facing each other, so that the inner surface of the plate-shaped member facing the tip surface faces each other. The thickness of the elastic body becomes thin, the vertical deformation is suppressed when a vertical load is applied, and the vertical load is more accurately transmitted to the load cell.

Further, as described in claim 3, the interval between the outer peripheral surface of the rod-shaped projection and the inner peripheral surface of the cylindrical projection is
By setting it so that it is not narrower than the distance between the tip surface of the cylindrical projection and the inner surface of the plate-like member, vertical deformation is minimized for vertical load, while horizontal and tilting It is ensured that the external forces in the directions are appropriately allowed to deform in those directions.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of the device of the present invention, in which 1 is an installation base, 2 is a load cell fixed on the installation base, and 3 is a load receiving device. Each member is shown.

Here, in this example, the pressure receiving portion 4 of the load cell 2 and the lower frame 5 of the load receiving member 3 are respectively provided.
For example, a load cell protection device 6 fixed by bolts is installed. As shown in FIG. 1 and FIG. 2, the load cell protection device 6 has two metal plates 7 and 8 as upper and lower plate-like members, which are substantially parallel to each other, facing each other and one disk 7 is opposed to the other. A rod-shaped projection 9 is provided at the center of the inner surface of the disk, and a metal ring-shaped projection 10 is provided on the inner surface of the other opposing disk 8 so as to surround the bar-shaped projection 9 at a distance.
An elastic body 1 in which the opposing surfaces of the discs 7 and 8 have a cylindrical appearance by including the protrusions 9 and 10 provided on the opposing surfaces.
1 (rubber) are connected to each other.

By the way, the load cell 2 shown in this example is
As shown in the plan view of FIG. 3, a frame having a plane shape defined by an inner contour line having a circular shape and an outer contour line having a substantially rectangular shape as a whole and which is in surface contact with the installation base 1. Fixing part 12
And a plurality of beam members 13 protruding inward in the radial direction from the frame-shaped fixing portion 12, here, a beam member 13 whose central portion in the length direction is constricted in a plan view, and the beam members 13 of these beam members 13. Connected to the tip, the planar contour shape is circular,
Pressure receiving part 4 that is located above the surface of the installation base 1
And a strain gauge 14 fixed on both upper and lower surfaces of each beam member 13 by sticking or the like.
The doscel 2 normally outputs a change in the resistance value of the strain gauge 14 based on the bending deformation amount of the beam member 13 according to the magnitude of the load acting on the pressure receiving portion 4.

Of course, the frame-shaped fixing portion 12, the beam member 13 and the pressure receiving portion 4 of the load cell 2 can be integrated after the individual construction of each of them. However, for example, it may be integrally formed by cutting out a material such as iron, aluminum, ceramics, or plastic, or integrally formed by casting, injection molding, or the like.

According to this example, the vehicle weight of, for example, a truck mounted on the load receiving member is the rod-shaped projection 9 of the upper disk 7.
Of the lower disk 8 and the lower disk 8 via a thin elastic body (rubber) 17, and a thin elastic body (rubber) 18 of the upper disk 7 and the front surface 16 of the ring-shaped projection 10 of the lower disk 8. As a result of the abutment via the load cell, the load cell protection device 6 is transmitted to the pressure receiving portion 4 of the load cell 2 under extremely small vertical deformation, and the vehicle weight energy is transmitted. Since there is little or no absorption by the deformation of 6, the vehicle weight measurement by the load cell 2 is performed with sufficiently high accuracy.

On the other hand, the load cell protection device 6
Is subjected to shearing deformation of the elastic body 19 surrounding the outer periphery of the ring-shaped projection 10 and sandwiched between the upper and lower disks 7 and 8 and the inside of the ring-shaped projection against the action of the external force in the horizontal direction. Shearing and stretching of the elastic body 20 when the rod-shaped projection 9 fixed to the filling elastic body 20 moves horizontally relative to each other, compression deformation, the tip surfaces 15 and 16 of the rod-shaped projection or the ring-shaped projection, and these tip surfaces. Since the elastic bodies 17, 18 sandwiched between the inner surfaces of the disks 8, 7 facing each other can be considerably deformed by shear deformation, for example, when a truck is loaded on the load receiving member 3, The external force in the horizontal direction generated by stopping the braking of the truck on the load receiving member is
The deformation of the douser protection device 6 is effectively absorbed, and the transmission of the external force in the horizontal direction to the load cell 2 is sufficiently relaxed.

Here, the interval between the outer peripheral surface of the rod-shaped projection and the inner peripheral surface of the cylindrical projection is set so as not to be smaller than the interval between the tip surface of the cylindrical projection and the inner surface of the plate-shaped member. ing.
That is, the space between the outer peripheral surface of the rod-shaped projection and the inner peripheral surface of the cylindrical projection is narrowed to increase the compression rigidity of the elastic body within the space, and the horizontal external force absorption capability of the load cell protection device is reduced. Are prevented.

Therefore, the influence of the horizontal external force on the vehicle weight measurement can be sufficiently eliminated, and the thin beam member 1 is also provided.
It is possible to eliminate the risk that the 3 is damaged by a large horizontal external force.

Further, in the load cell protection device 6, the relative tilting of the upper and lower disks 7 and 8 is fixed to the ring-shaped projections 10 by the outer circumference of the ring-shaped projection 10 so as to be sandwiched between the upper and lower disks 7 and 8. 10 left and right extension, compression deformation and bar-shaped projection 9
Can be made sufficiently large by twisting deformation and the like caused by tilting of the ring-shaped projection 10 in the cylinder. However, in this case, it is necessary to set the thickness of the elastic body 19 and the width of the ring-shaped projection 10 from the outer peripheral surface to be large according to the diameter of the ring-shaped projection 10. Therefore, the installation base 1
The inclination of the mounting surface of at least one of the load receiving member 3 and the load receiving member 3 can be absorbed without exerting an unreasonable force on the load cell 2. Therefore, the force in the tilting direction of both disks 7, 8 can be reduced. −
It is possible to effectively eliminate the action on the douser 2 to enhance the measurement accuracy of the vehicle weight, and at the same time, prevent the load cell beam member 13 from being damaged.

For example, when only the vertical load acts on the load cell 2, the load cell 2 can be prevented from being damaged by designing the load cell 2 according to the estimated weight of measurement. When a load acts on the load member 3 at a position distant from the load cell 2, the load cell 2 has a large value which is a sum of the load and the moment arm length, which is much larger than the expected load to be measured. Where the load cell 2 may be damaged by the action of the moment, as described above, when the relative tilting of the two disks is sufficiently allowed, the force in the tilting direction is thereby exerted. It can be effectively absorbed to protect the load cell 2 effectively.

In the example shown in this example,
The structure of the doscel 2 can be various known ones, and the outer contour of the load cell protection device 6, which is substantially the same as the pressure receiving part 4 in the figure, is the same as that of the frame-shaped fixing part 12. The load cell protection device 6 may be substantially the same, and the load cell protection device 6 may be disposed between the load cell 2 and the installation base 1.

FIG. 4 is a vertical sectional view showing another embodiment of the load cell protection device 6. In the example shown in FIG. 4, an annular notch 21 extending over the entire circumference is provided on the side wall of the elastic body 11, which can be a columnar shape, a polygonal columnar shape, or the like. According to this example, the notch Under the action of 21, it is possible to further increase the horizontal relative displacement amount and relative tilt amount of the upper and lower disks 7 and 8, respectively, and this becomes more remarkable when a plurality of notches 21 are provided. . In this example, when the notches 21 are intermittently provided at intervals in the circumferential direction of the elastic body 11, it is possible to give the horizontal displacement amount and the tilt amount a desired directivity. .

In the above-mentioned embodiment, the cylindrical projections projectingly provided on the plate-shaped member are in the shape of a ring continuous in the circumferential direction. However, for the purpose of the present invention, the cylindrical projection is not limited to this. The projection may be divided at several positions in the circumferential direction.

[0030]

As is apparent from the above description,
According to the present invention, particularly under the action of the rod-shaped projections and the ring-shaped projections provided on the inner surfaces of the upper and lower plate-like members,
It is possible to effectively prevent the compressive deformation of the device with respect to the vertical load, and on the other hand, it is possible to sufficiently allow both the large horizontal deformation and the tilting direction deformation of the device. Can be effectively improved, and the load cell can be effectively protected against external force.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment according to the present invention.

FIG. 2 is a diagram showing a side view and a plan view of a plate member.

FIG. 3 is a plan view illustrating a load cell.

FIG. 4 is a vertical sectional view showing another embodiment according to the present invention.

FIG. 5 is a plan view of a platform scale for vehicle weight measurement.

FIG. 6 is a front view showing a conventional example.

FIG. 7A is a plan view showing another conventional example. (B) It is a front view which shows another prior art example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Installation base 2 Road cell 3 Load receiving member 4 Pressure receiving part 5 Lower frame 6 Road cell protection device 7 (Upper) plate-shaped member 8 (Lower) plate-shaped member 9 Rod-shaped protrusion 10 Ring-shaped protrusion 11 Elasticity Body 12 Frame-shaped fixing portion 13 Beam member 14 Strain gauge 15 Tip surface 16 Tip surface 17 Thin elastic body (Elastic body sandwiched between the rod-shaped projection tip surface and the inner surface of the plate-like member facing) 18 Thin elastic body (Elastic body narrowly attached to the inner surface of the plate-shaped member facing the tip end surface of the cylindrical protrusion) 19 Elastic body narrowly attached to the upper and lower plate-shaped members at the outer peripheral portion of the ring-shaped protrusion 20 Inside the cylinder of the ring-shaped protrusion Elastic body 21 notch

Claims (3)

[Claims] 1. A load cell comprising a load cell and a load receiving member, which are sequentially arranged on the installation base, between the load cell and the load receiving member, or between the load base and the installation base. A load cell protection device interposed between two plate-shaped members that are substantially parallel to each other, and a bar-shaped projection is provided at the center of the inner surface of one plate-shaped member, and Cylindrical projections that are arranged concentrically outside the rod-shaped projections are provided on the inner surface of the plate-shaped member, and the facing surfaces of these plate-shaped members are provided by an elastic body that includes the projections provided on the facing surface. A load cell protection device that is interconnected. 2. The load cell protection device according to claim 1, wherein a leading portion of the rod-shaped protrusion is arranged in the cylinder of the cylindrical protrusion. 3. The gap between the outer peripheral surface of the rod-shaped projection and the inner peripheral surface of the cylindrical projection is not smaller than the distance between the tip surface of the cylindrical projection and the inner surface of the plate-shaped member. The load cell protection device according to 1 or 2.