JPH0114893Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a weighing device using a load cell. In recent years, load cells have been attracting attention as the weighing part of weighing devices. However, this load cell is susceptible to excessive loads, and if an excessively large load is applied, so-called zero point drift may occur, resulting in weighing errors.
In extreme cases, it may be damaged. Therefore, various overload prevention devices have been proposed.
All of these methods are unsuitable because they have complicated configurations and cannot sufficiently prevent overloads.

Therefore, the present invention provides a weighing device that has a simple configuration and can reliably prevent overload.

Hereinafter, one embodiment of the present invention will be described based on the drawings. 1 is a scale exterior case, 2 is a substantially L-shaped fixing block disposed on the bottom surface of the case 1, and 3
The base end 3a is the rising part 2a of the block 2.
The leaf spring is fixed to the upper surface with bolts 4, and its free end 3b is in the state shown by the phantom line in FIG. 1 in its natural state. 2c stands up from both edges of the base end 2b of the block 2, and its L-shaped bent end face presses the free end 3b of the leaf spring 3 to hold the free end 3b in a vertical state. A pair of first stoppers 5 is a load cell, which includes a parallelogram-shaped cell body 6 consisting of a pair of vertical parts 6a, 6b and horizontal parts 6c, 6d, each horizontal part 6c,
A strain gauge 8 is attached to a thin portion 7 formed near the end of the strain gauge 6d. One of the vertical parts 6b is the first vertical part 6b of the free end 3b of the leaf spring 3.
Bolts 10 are fastened to the stopper pressing surface, whereby the load cell 5 is suspended from the leaf spring 3. 1
1 is L fixed to the other vertical part 6a with bolts 12
The L-shaped rod 13 is a pin that is erected on the horizontal part of the L-shaped rod 11 and passes through the hole 14 in the top plate of the case 1;
Reference numeral 15 designates a weighing tray whose cylindrical portion at the center of the lower surface fits into the pin 13, and reference numeral 2d designates a second stopper protruding from a location below the other vertical portion 6a of the base plate portion 2b of the block 2.

In the above configuration, when a heavy object to be weighed is placed on the weighing tray 15, a load is applied to the moving side vertical portion 6a of the load cell 5 through the pin 13 and the L-shaped rod 11, and a voltage is output from the strain gauge 8. ,A/
The weight value is converted into D and displayed digitally.

By the way, if the maximum weighing value of this scale is, for example, 6 kg, the leaf spring 3 is
The free end 3b of the leaf spring 3 is pressed, and the resulting repulsive force F of the leaf spring 3 is set to 6 kg or more (for example, 8 kg). As a result, if the weight of the heavy object to be weighed placed on the weighing pan 15 is up to 6 kg (actually up to 8 kg), the free end 3b of the leaf spring 3 will not sway and will be accurate. It is possible to carry out weighing. If a heavy object to be weighed is placed on the weighing tray 15 with an impact, and the impact force W is, for example, 150 kg,
The repulsive force F of the leaf spring 3 is defeated by the impact force W, and the leaf spring 3 is bent, the load cell 5 moves in the direction of the arrow A, and the vertical portion 6a on the moving side moves to the second stopper 2d.
At this point, the fixed block 2 directly receives the impact force W. Therefore, both horizontal parts 6c, 6
d is not forcibly bent beyond the set value.

As described above, according to the weighing device of the present invention,
A leaf spring is provided whose base end is supported by a fixed body and whose free end is swingable, and a first stopper is provided that presses the free end in one direction and holds the free end in a vertical state. Since the load cell is suspended from the free end, during normal weighing, the repulsive force of the leaf spring overcomes the load applied to the weight receiver, so that the load cell is supported by a fixed body. The condition will be the same as that, and accurate weighing can be performed. In addition, when an overload is applied to the weight receiver, a second stopper is provided that bends the plate spring and prevents the load cell from moving beyond a predetermined amount, so this second stopper will directly receive the overload. Therefore, both horizontal parts of the load cell are not forcibly bent beyond the set value. Therefore,
This can prevent so-called zero point drift and damage to the load cell.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a longitudinal cross-sectional view, and FIG. 2 is a view taken along the - arrow in FIG. 1. 2... Fixed block, 2c... First stopper, 2d
...Second stopper, 3...Plate spring, 3a...Base end, 3
b...Free end portion, 5...Load cell, 6...Cell body, 6
a, 6b...vertical part, 6c, 6d...horizontal part, 8...strain gauge, 15...weighing pan (weighing pan).

Claims (1)

[Scope of utility model registration request] A leaf spring is provided whose base end is supported by a fixed body and whose free end is swingable, and a first stopper is provided that presses the free end in one direction and holds the free end in a vertical state. , one of the vertical parts of the load cell has a parallelogram-shaped cell body consisting of a pair of vertical parts and a horizontal part, and a strain gauge affixed to each of the horizontal parts. One stopper is fixed to the pressing surface, and a weight receiver is fixed to the other vertical part to prevent the plate spring from being bent and the load cell to move more than a predetermined amount due to an overload applied to the load cell through the weight receiver. A weighing device characterized by being provided with a second stopper.