JP2000266587A - Load cell type platform scale - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load cell type platform scale which suppresses production cost lower while facilitating the adjustment of deviation errors. SOLUTION: This load cell type platform scale is provided with a plurality of single leverages 4 which are made independent of one another to receive a load from a platform 2 and one load cell 3 which receives forces from the plurality of the single leverages 4 at different points of application to measure the load and the forces from the plurality of the single leverages 4 are received by the load cell 3 at different points of application through a load receiving part 6 to measure the load. This can make the platform 2 or the like less in rigidity while simplifying the structure thereof and furthermore, makes the single leverages 1 the same in shape and structure thereby achieving a reduction in the production cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load cell type platform scale.

[0002]

2. Description of the Related Art Weighing is 30 kg to 2 tons and the number of graduations is 2000
A conventional structure of a load cell type platform scale having a degree or more includes the following types. The mounting table is directly supported by one load cell. For example, as shown in Japanese Patent Publication No. 58-51604,
One-point load cell type (hereinafter abbreviated as OLC type).

A multi-load cell type (hereinafter abbreviated as MLC type) in which a mounting table is supported by a plurality of load cells. As shown in FIG. 7, while supporting the mounting table 31 with four emphasis, represented by a load cell type health meter,
One long body 33, which is a cooperative united lever 32 having two fulcrums, a point of emphasis, and one power point, and two short bodies 34, which are single levers, are connected in series to apply a load to the power point of the long body. Of a lever load cell type (hereinafter, abbreviated as LLC type) in which the load is concentrated on one load cell 35 and weighed. In FIG. 7, reference numeral 36 denotes a digital instruction unit, and reference numeral 37 denotes a base.

[0004]

However, the OLC
6, the load cell 21 is directly fixed to the mounting table 22 and the base (base frame) 23, so that the rigidity of the mounting portion of the mounting table 22 and the base and the flatness of the mounting surface are appropriate. Otherwise, there is a problem that the weighing accuracy is hindered. Further, since the mounting table 22 is supported at one point by the load cell 21, the mounting table is supported at a plurality of points.
The mounting table 22 and the base 2 are different from those of the LC type and the LLC type.
All three must have a sturdy structure and weigh 100
When the mounting table size is about 400 × 400 (mm) or more at kg or more, the manufacturing cost increases. Furthermore, even if the eccentricity error adjustment of the load cell alone is performed,
If the rigidity of the mounting portion of the mounting table 22 and the base 23 and the flatness of the mounting surface are not appropriate after the scale is assembled, the load cell 2
Detrimental torsional and bending moments act on 1 to increase the eccentricity error, and readjustment of the eccentricity error may take a lot of trouble and time. See Japanese Patent Publication No. 58-51604 for the method of adjusting the eccentric error.

Since the MLC type platform scale has a plurality of load cells, the mounting platform size is 1000 × 1000 (mm).
Otherwise, the ratio of the load cell price to the total price increases, which is disadvantageous in cost.
The LLC-type platform scale concentrates the load at one point via the lever and applies the load to the load cell. In particular, the structure of the long body 33, which is the cooperative united lever 32 having two fulcrums and the emphasis, is complicated. This increased the production cost.
In addition, the eccentricity error of the LLC type is mainly caused by the variation of the leverage ratio, but in order to adjust the leverage ratio of the elongated body 33, the minute distance between the fulcrum and the important point must be adjusted. However, it is difficult to properly perform the deviation error adjustment unless it is a so-called specialized craftsman.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a load cell type weighing system capable of reducing the manufacturing cost and easily adjusting the deviation error. .

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a load cell type platform scale according to the present invention receives a load from a platform and is not connected to or engaged with each other. , A plurality of single levers, each of which is independently disposed, and one load cell that receives loads from the plurality of single levers at different force application points and measures a load.

[0008] According to this structure, since the mounting table is supported at a plurality of points, the rigidity of the mounting table or the like can be reduced, thereby reducing the manufacturing cost and connecting the levers to each other. Since they do not fit or hang together, the structure can be simplified, and since the single lever can have the same shape and structure, the structure can be further simplified, thereby also reducing the manufacturing cost. Can be reduced.

According to a second aspect of the present invention, there is provided the load cell type platform scale according to the first aspect, wherein the mounting table is supported so as to be able to swing substantially in a lateral direction between the mounting table and the unit. A lateral load relief device for releasing a lateral force acting on the table is provided. According to this configuration, when a lateral load is applied to the mounting table, or when a vertical load applied to the mounting table causes a lateral load to be applied to the important portion caused by the bending of the mounting table,
Since this lateral load is released by the lateral load releasing device, no lateral load acts on the fulcrum or the crucial point, there is no change in the contact position between the blade and the blade receiver, and wear can be prevented, so that good accuracy is maintained.

According to a third aspect of the present invention, in the load cell type platform scale according to the second aspect, the lateral load relief device is attached to a middle frame arranged in a frame shape below the mounting table, and the middle frame is provided. In addition, a key member that engages with the key lever of the single lever is attached. According to this configuration,
Since the lateral load relief device is attached to the middle frame arranged in a frame shape, the mounting table is stably supported via the middle frame.

According to a fourth aspect of the present invention, in the load cell type platform scale according to any one of the first to third aspects, a mechanism for adjusting a distance between a fulcrum and a force point in a single lever is provided. is there. With this configuration, the deviation error of the entire scale can be adjusted efficiently with a relatively simple operation.

According to a fifth aspect of the present invention, in the load cell type platform scale according to any one of the first to fourth aspects, a fulcrum blade attached to a single lever, a fulcrum blade receiver for receiving the fulcrum blade, At least one of the emphasis blade attached to the single lever and the emphasis member engaged with the emphasis blade is an extruded product. With this configuration, the manufacturing cost can be further reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a platform scale according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 5, this platform scale is a single load cell formed by attaching a plurality of strain gauges to a strain body within a space surrounded by a base (base frame) 1 and a platform 2. 3 and four single levers 4 as independent first sticks, which are not connected or engaged with each other. The fixed portion side of the load cell 3 is fixed on the base 1 via a fixed bracket 5, and the load receiving portion 6 having load receiving levers 6a extending to four sides is fixed to the movable portion side of the load cell 3. Have been. In addition, 1 in FIG.
Reference numeral 9 denotes a spring for preventing the mounting table 2 from coming off the base 1 side.

At four corners of the base 1, fulcrum blade receivers 7 each having a V-shaped groove are fixed in an upright posture. The fulcrum blade receivers 7 are press-fitted into holes formed at one end of the single lever 4. A fulcrum blade 8 having a rhombic cross section is engaged from above to form a fulcrum A. A hole is also formed at a portion of the single lever 4 near the fulcrum A, and the emphasis blade 9 having a rhombic cross section is press-fitted into this hole, and the emphasis member 10 having a V-shaped groove in the emphasis blade 9 is formed. Each of them is engaged from above and is set as a priority point B. The fulcrum blade receiver 7, the fulcrum blade 8, the important blade 9, and the important member 10 are formed by extrusion molding. Each of the important members 10 is fixed to the lower surface of a plane substantially rectangular frame-shaped middle frame 11 arranged on the back side of the mounting table 2. Between them, lateral load relief devices 12 each composed of a ball and a pair of spherical seats are interposed. And the platform 2
The lateral load acting on the single lever 4 is released by the lateral load releasing device 12 so that the lateral load does not act on the priority blade 9 of the single lever 4.

The other end of the single lever 4 is engaged with the load receiving lever 6a of the load receiving member 6 via the suspension ring 13, and a point at which the force is transmitted by the suspension ring 13 is defined as a force point C. I have.
As shown in FIGS. 4 and 5, the single lever 4 can adjust a distance G between the fulcrum A and the power point C, more specifically, a distance E between the important point B and the power point C, By adjusting the distance E between the important point B and the power point C in this manner, the deviation error of the load cell 3 and the leverage ratio of each single lever 4 (= distance between fulcrum important points /
A deviation error of the entire platform scale due to a variation in the fulcrum force point distance) can be corrected. In this embodiment, a single lever 4 has a pair of main arms 14 into which the fulcrum blades 8 and the important blades 9 are press-fitted at one end side, and a suspension ring 13 sandwiched between the main arms 14 at the other end side. And an auxiliary arm 15 that engages with the main arm 14, and is fastened by a fastening bolt 16 through an elongated hole 14 a formed at an end of the main arm 14 and an insertion hole formed in the auxiliary arm 15. Then, the distance G between the fulcrum A and the force point C can be adjusted by loosening the fastening bolt 16 and moving the sub arm 15 relative to the main arm 14 in the longitudinal direction (D direction). I have.

In the above configuration, when a load is applied to the mounting table 2, the load acts on the important point B, which is an engagement point between the important member 10 and the important blade 9, and the fulcrum blade 8 and the fulcrum blade receiver 7 Is set as a fulcrum A, a force point (force application point) C for transmitting a force to the load receiving lever 6a of the load receiving member 6 via the suspension ring 13 is applied to a force proportional to the load on the important point B, specifically, Is the load on the important point B, and the force obtained by integrating this ratio (distance F between the fulcrum points / distance G between the fulcrum force points (= E + F)) acts. Then, the load from the four force points C is received by the movable portion side of the load cell 3 via the load receiving member 6, and the load is measured by the load cell 3.

In this case, the single lever 4 has the same shape and structure, and does not have a complicated structure unlike the conventional case of using a cooperative joint lever having two fulcrums and important points. It is easy to manufacture and the manufacturing cost can be reduced. In addition, since the mounting table 2 is supported at four points, the rigidity of the members together with the mounting table 2 and the base 1 can be reduced, and the manufacturing cost can be reduced.

When a lateral load is applied to the key member 10 or the single lever 4, a point where the key member 10 and the key blade 9 are engaged and a point where the fulcrum blade 8 and the fulcrum blade receiver 7 are engaged are changed. However, even when a lateral load is applied to the mounting table 2, the lateral load is released by the horizontal swinging device 12, so that the Since the lateral load does not act on the support 9 and the fulcrum 8, the above-mentioned problems are prevented from occurring.

Further, the load acting point on the load cell 3 is
Since it is a small area where the load receiving member 6 is provided, the influence of the eccentric error of the load cell 3 is substantially reduced. However, although there is a small amount, the deviation of the load cell 3 slightly exists, and the dispersion of the lever ratio also exists due to a manufacturing error. Is corrected by adjusting the distance G between the fulcrum and force points by shifting the connection position of.

Here, for example, the fulcrum center distance E is 35
mm, the distance G between the fulcrum force points is 250 mm, and the lever ratio is 1 in a single lever 4 having a lever ratio of 35/250.
/ 2000 to change it, the LLC
When adjusting the distance between the fulcrum A and the important point B using the scale of the formula, the distance between the fulcrum A and the important point B is set to 35/200.
The adjustment must be made by 0 = 0.175 mm, and it is difficult for a non-professional worker to perform the deviation error adjustment properly. However, in this load cell type platform scale, the distance G between the fulcrum A and the force point C is 25 degrees.
It is only necessary to adjust 0/2000 mm = 0.125 mm, that is, since the adjustment width is increased by the reciprocal of the lever ratio (250/35 = 7.14 times), the adjustment work becomes easier by that amount, and as a result, high precision A simple load cell type platform scale can be manufactured efficiently with relatively simple adjustment work.

In the above embodiment, the number of the single levers 4 is four.
It is not limited. Further, in the above embodiment, the distance adjusting mechanism for adjusting the distance G between the fulcrum A and the force point C has been described as a mechanism for moving the rolling position within the elongated hole 14a, but is not limited thereto. For example, an adjustment screw may be arranged along the longitudinal direction of a single lever, and the auxiliary arm may be moved by turning the adjustment screw. In addition, since the fulcrum blade receiver 7, the fulcrum blade 8, the important blade 9, and the important member 10 are formed by extrusion molding, the manufacturing cost can be reduced by this.
Only a part of these may be constituted by an extruded product.

[0022]

As described above, according to the present invention, a plurality of single levers, each of which is independent and receives a load from the mounting table, and the forces from the plurality of single levers are subjected to different force actions. With a single load cell that receives a load at a point and measures the load, the platform and the like can be reduced in rigidity, the structure can be simplified, and a single lever can be used with the same shape and structure. It is also possible to
Manufacturing costs can be reduced.

[0023] Further, by providing a lateral load releasing device for supporting the mounting table so as to be able to swing substantially in the lateral direction between the mounting table and the single unit, and releasing the lateral force acting on the mounting table. Even when a lateral load is applied to the mounting table, or when a vertical load applied to the mounting table causes a lateral load to be applied to the important point due to the bending of the mounting table, the lateral load is released by the lateral load relief device. Since the lateral load does not act on the fulcrum and the point of importance,
Since there is no change in the contact position between the blade and the blade receiver and wear can be prevented, good accuracy can be maintained.

Further, by providing a distance adjusting mechanism for adjusting the distance between the fulcrum and the force point in each single lever, the deviation error of the entire scale can be adjusted by a relatively simple operation. A highly accurate load cell type platform scale can be manufactured efficiently.

[Brief description of the drawings]

FIG. 1 is a plan sectional view of a load cell type platform scale according to an embodiment of the present invention.

FIG. 2 is a front sectional view of the load cell type platform scale.

FIG. 3 is a side sectional view of the load cell type platform scale.

FIG. 4 is a front sectional view of a single lever arrangement position of the load cell type platform scale.

FIG. 5 is a plan cross-sectional view of a single lever arrangement position of the load cell type platform scale.

FIG. 6 is a schematic front sectional view showing a conventional one-point load cell type platform scale.

FIG. 7 is an exploded perspective view showing a conventional lever load cell type platform scale.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 base 2 mounting table 3 load cell 4 single lever 6 load receiving part 7 fulcrum blade support 8 fulcrum blade 9 important blade 10 important member 12 lateral load relief device 13 suspension ring 14 main arm 14a long hole 15 auxiliary arm 16 fastening bolt

Claims (5)

[Claims] 1. A plurality of single levers, each of which is independently arranged without being connected or engaged with each other under a load from a mounting table, from a plurality of single levers Load cell-type platform scale having one load cell for measuring a load by receiving different forces at different force application points. 2. A lateral load relieving device for supporting a platform in such a manner as to be able to swing substantially in a lateral direction between a platform and a single support to release a lateral force acting on the platform. Item 1. The load cell type platform scale according to item 1. 3. The lateral load relief device is attached to a middle frame arranged in a frame shape below the mounting table.
3. The load cell type platform scale according to claim 2, wherein a weight member that engages with the weight lever of the single lever is attached. 4. The load cell type platform scale according to claim 1, further comprising a mechanism for adjusting a distance between a fulcrum and a power point in a single lever. 5. A fulcrum blade attached to a single lever, a fulcrum blade receiver for receiving the fulcrum blade, a priority blade attached to the single lever, and at least one of a priority member engaged with the priority blade. The load cell type platform scale according to any one of claims 1 to 4, wherein the one is an extruded product.