JPH0528937U - Stopper mechanism of load cell - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the load cell from being deformed more than specified. [Configuration] Rear end 22c of the cell body 22 of the load cell 21
The side is fixed to one end 13b of the support plate 13. The other end 13a side of the support plate 13 is fixed to the housing. Both ends of the round shaft 31 are horizontally projected on the side surface of the boss 30 attached to the front end of the load cell 21. Above and below the round shaft 31, an upper stopper piece 38a and a lower stopper piece 38b fixed to the housing extend with a predetermined gap. A hopper support plate 35 for supporting the weighing hopper is attached to the lower end of the connecting shaft 33 attached to the lower surface side of the boss 30. When a load larger than the specified value is applied via the connecting shaft 33, the round shaft of the boss 30 and the upper and lower stopper pieces 38a, 38b come into contact with each other in a line contact state, so that the deformation of the load cell 21 including the twist larger than the specified value is restricted. It

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a stopper mechanism for a load cell that is used in a weighing machine or the like and outputs an electric signal according to a deformation caused by a load.

[0002]

[Prior art and problems to be solved]

 A load cell often used in weighing machines and the like is generally configured as shown in FIG.

The load cell 1 is configured such that the same strain gauges 3 are attached to the front and rear of the upper surface 2a and the lower surface 2b of a rectangular cell body 2, respectively.

The four strain gauges 3 whose resistance values change due to strain are electrically connected so as to form a bridge circuit, and as shown in FIG. 8B, one end 2 c of the cell body 2 is connected. When the side is fixed and a load F is applied from above the other end 2d side, the resistance value of each strain gauge 3 changes due to the deformation of the cell body 2, so that the bridge circuit changes from the balanced state to the unbalanced state. , It is possible to output an electric signal corresponding to the load.

However, the mechanical strength of the load cell 1 is limited, and if the load cell 1 is deformed by more than a specified size, it is significantly deteriorated or damaged.

Therefore, a stopper mechanism as shown in FIG. 9A has been conventionally used.

In this mechanism, a boss 5 for receiving a load is attached to an end portion 2d on the load side of the cell body 2, and a protruding piece 5a is horizontally provided from the boss 5 along the length direction of the load cell 1. The upward and downward movement of the protruding piece 5a beyond the specified dimension is restricted by the stopper screws 7 and 8 of the U-shaped stopper support plate 6.

The positions of the upper and lower stopper screws 7 and 8 are adjusted by using a gap gauge or the like so that the gap between the tips 7a and 8a and the protruding piece 5a has a predetermined dimension.

However, in the conventional stopper mechanism as described above, when a load larger than the specified value is applied in the twisting direction of the boss 5, as shown in FIG. There was a case in which the load cell 1 was rotated about the contact position with the tip 7a as a fulcrum, and the load cell 1 was also subjected to this twisting direction force, causing damage or deterioration of the load cell.

Particularly, in various weighing machines in which a hopper mounting portion is often directly connected to the boss 5, a force in the twisting direction is easily applied by a work such as mounting or removing the hopper, which may cause deterioration of the load cell. There was a lot of damage.

The present invention aims to provide a load cell stopper mechanism that solves this problem.

[0012]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, a stopper mechanism for a load cell according to the present invention is a stopper mechanism for a load cell, which regulates a movement of the other end side of a load cell whose one end side is fixed within a predetermined dimension. A boss that is attached to the other end and that transmits the load to the load cell, and a boss that moves in the load direction have a line or a plurality of lines along the length direction of the load cell and a direction orthogonal to the load direction. And a stopper member that abuts at a point and restricts the movement of the boss within the predetermined dimension.

[0013]

[Action]

 With this configuration, in the load cell stopper mechanism of the present invention, when a force greater than a predetermined value including the load direction is applied to the boss body attached to the other end side of the load cell, the boss body will move. The stopper member comes into contact with the stopper member at a line or at a plurality of points along the length direction and the direction orthogonal to the load direction, and the movement of the other end side of the load cell is regulated within a predetermined dimension without any twist.

[0014]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a main part showing a stopper mechanism in which the present invention is applied to a load cell 21 in a casing 10 of a combination weighing machine, FIG. 2 is a plan view thereof, and FIG. 3 is a part thereof. It is the side view which fractured | ruptured.

The casing 10 has a circular or polygonal outer periphery, and a supply device for supplying the articles to the respective weighing hoppers 15 is attached to the upper portion of the outer periphery (not shown).

A shaft hole 12 for inserting a connecting shaft 33, which will be described later, is provided in an upper portion 11 a of the recessed portion 11 of the housing 10, and an inner wall of the vertical portion 11 b of the recessed portion 11 is provided behind the load cell 21. One end 13a of the support plate 13 for fixing and supporting the end is bolted.

The cell body 22 of the load cell 21 is formed into a substantially rectangular parallelepiped, and strain gauges 23 are attached to the front and back of the upper surface 22a and the lower surface 22b thereof.

Bolt holes 24 and 25 penetrating from the upper surface 22a to the lower surface 22b are provided in the rear end 22c and the front end 22d of the cell body 22, and the bolt holes 24 on the rear end 22c side are provided with holes of the support plate 13. The other end 13b side is bolted from the lower surface side.

The load cell 21 is supported by the support plate 13 in a substantially horizontal state.

On the front end 22d side of the cell body 22, a rear portion 30a of the boss 30 that engages with the front end shape is fixed by bolting from above.

A round shaft 31 orthogonal to the length direction of the load cell 21 and its load direction (vertical direction) is attached to the front portion 30b of the boss 30 so as to penetrate the side surfaces 30c and 30d of the boss 30. ..

An upper end side 33 a of the connecting shaft 33 is fixed to the lower surface 30 e of the boss 30.

The connecting shaft 33 is inserted through the shaft hole 12 of the housing 10, and the lower end portion 33 b protruding to the outside of the housing 10 has a hopper support plate 35 for supporting the weighing hopper 15. Is bolted. A bellows-like waterproof cover 34 is attached between the shaft hole 12 and the connecting shaft 33.

In front of the boss 30, a stopper 37 for restricting the vertical movement of the round shaft 31 beyond a prescribed dimension is bolted to the housing inner wall 10 a above the recess 11.

The stopper 37 has an upper stopper piece 38 a and a lower stopper piece 38 b which extend horizontally above and below both ends 31 a and 31 b of the round shaft 31 at intervals wider than the width of the boss 30 on both sides. There is.

The gap between the upper stopper piece 38 a and the lower stopper piece 38 b is set in advance to a value obtained by adding the outer diameter of the round shaft 31 to a value obtained by doubling the allowable deformation dimension of the load cell 21.

Further, the stopper 37 is previously fixed at a position where the clearance between the round shaft 31 and the upper and lower stopper pieces 38a and 38b is an allowable deformation dimension while the weighing hopper 15 is supported by the hopper support plate 35. Has been done.

Next, the operation of this stopper mechanism will be described.

When an article is dropped and fed into the weighing hopper 15 from a feeder (not shown) on the upper part of the housing, the load F is transmitted to the boss 30 via the connecting shaft 33, and thus is shown in FIG. As described above, the front end 22d of the cell body 22 slightly descends downward.

When this load is due to the amount of articles supplied during normal operation of the weighing machine, the lower dimension of the round shaft 31 is small and does not hit the lower stopper piece 38b.

It should be noted that the weight of the supplied article is detected by the resistance change of the strain gauge 23 due to this load, and the weight is selected in combination with the weight values of the other hoppers.

When the articles supplied to the weighing hopper 15 are selected for combination, a gate (not shown) of the weighing hopper 15 is opened by a drive device (not shown) in the housing 10, and the hopper is opened. The weighed articles contained in the inside are discharged downward and collected together with the articles in the other weighing hoppers selected for the combination.

In addition, when a large downward load F ′ including the twisting direction of the load cell 21 is applied when the weighing hopper 15 is attached or detached, the boss 30 is attached to the round shaft 31 as shown in FIG. Since the load cells 21 are regulated by the line contact between the both ends 31a, 31b and the lower stoppers 38a, 38a of both the stoppers 37, a large twisting force is not applied to the load cell 21.

This is the same even when an upward load is applied, and problems such as deterioration of the performance and damage of the load cell 21 do not occur.

In this embodiment, the load cell 21 is prevented from being deformed by supporting the round shaft 31 projecting to the side of the boss 30 and the upper stopper 38a or the lower stopper 38b at two points by line contact. However, as shown in FIG. 6, hemispherical spherical projections 41 are provided on the upper and lower sides of the projecting piece 40a of the conventional boss 40 on both sides, and the upper stopper piece 42a of the U-shaped stopper 42 is provided. The lower stopper piece 42b may restrict the boss 40 from moving more than the specified amount.

In addition, as shown in FIG. 7, a plurality of spherical protrusions 41 (or semi-cylindrical protrusions) are provided on the opposing surfaces of the upper and lower stopper pieces 42 a and 42 b of the stopper 42 in the length direction and the load direction of the load cell 21. You may make it arrange | position along the direction orthogonal to.

[0038]

[Effect of the device]

 As described above, the stopper mechanism of the load cell of the present invention allows the movement of the boss body on the other end side of the load cell whose one end side is fixed along the direction orthogonal to the length direction and the load direction of the load cell. It is configured to be regulated by a stopper that abuts the boss at a curved line or at multiple points.

Therefore, even if a large load including the direction in which the load cell is twisted is applied, the load cell is not deformed more than the specified value, and deterioration or damage of its performance can be prevented in advance.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of an embodiment of the present invention.

FIG. 2 is a plan view of an example.

FIG. 3 is a side view in which a part of an example is cut away.

FIG. 4 is a schematic diagram for explaining the operation of one embodiment.

FIG. 5 is a schematic diagram for explaining the operation of one embodiment.

FIG. 6 is a schematic view showing a main part of another embodiment.

FIG. 7 is a schematic diagram showing a main part of another embodiment.

FIG. 8 is a side view of the load cell.

FIG. 9 is a side view of a conventional mechanism.

FIG. 10 is a diagram for explaining the operation of the conventional mechanism.

[Explanation of symbols]

 10 Case 11 Cavity 12 Shaft Hole 13 Support Plate 15 Weighing Hopper 21 Load Cell 22 Cell Main Body 23 Strain Gauge 24, 25 Bolt Hole 30 Boss 31 Round Shaft 33 Connection Shaft 35 Hopper Support Plate 37 Stopper 38a Upper Stopper Piece 38b Lower Stopper Piece

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[Procedure amendment]

[Submission date] November 22, 1991

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

[Figure 9]

[Figure 10]

Claims (1)

[Scope of utility model registration request] 1. A load cell stopper mechanism for restricting movement of the other end side of a load cell whose one end side is fixed within a predetermined dimension in a load cell stopper mechanism which is attached to the other end side of the load cell. And a boss body that moves in the load direction, contact the boss body that moves in the load direction with a line or a plurality of points along a direction orthogonal to the length direction of the load cell and the load direction to move the boss body. A stopper mechanism for a load cell, comprising: a stopper member that regulates within the predetermined dimension.