JPH027003B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a load measuring actuator in a weighing machine.

[Conventional technology and problems]

Conventionally, this type of device has been designed to apply a load to be measured to one end of a ram which is rotatably supported on a fulcrum, and to apply a load for balancing the ram to the other end, and a magnet, A load measuring actuator consisting of a bobbin and a coil wound around the bobbin is provided, and a vertical force is generated by the interaction between the current flowing through the coil and the magnetic flux from the magnet, and the magnetic force balances the hammer rod. A weighing machine that uses this technology is known.

Generally, when not in use, for example, the ramrod is stabilized by lowering it at the other end, that is, the load measuring actuator side, but even when not in use, the ramming rod and the load measuring actuator remain in contact with the surroundings even when they are not in use. It is susceptible to vibrations, etc., and is difficult to handle. It is also a source of error.

[Object and structure of the invention]

The present invention was made in view of the above problems, and an object of the present invention is to provide a load measuring actuator for a weighing machine that is hardly affected by surrounding vibrations. According to the present invention, this object is achieved by the load measuring actuator having the above configuration, characterized in that at least a portion of the bobbin that faces the magnet in the vertical direction is made of a material containing a magnetic material. .

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A ram type weighing machine according to an embodiment of the present invention will be described below with reference to the drawings.

In the figure, the ramrod type weighing machine is indicated as 1 as a whole, and the ramrod, so-called pole 2, is supported at a fulcrum 4 on one support 3a of a frame 3, and a loading plate 6 is suspended via a fulcrum 5 at one end thereof. It's hanging. Also,
At the other end, the actuating rod 8 of the load-measuring actuator 7 is pivotally mounted.

In addition to the above-mentioned actuating rod 8, the load measuring actuator 7 includes a bobbin 9 and a coil 1 wound around the bobbin 9.
0, permanent magnet 11, yoke 12a, 12b, 12
The magnetic flux from the permanent magnet 11 crosses the coil 10 as shown by the arrow and connects the yokes 12a,
12b and 12c. When the coil 10 is energized with a direct current in a predetermined direction, the interaction between this current and the magnetic flux generates a downward force F, which pulls the actuating rod 8 downward as shown by the arrow. By controlling the magnitude of the current applied to the coil 10, this force F is adjusted and balanced with the weight of the object to be measured placed on the placing plate 6.

According to this embodiment, the bobbin 9 is made of aluminum containing a magnetic material (for example, iron).

A stopper mounting block 13 is fixed on the other support column 3b of the frame 3, and the tip of the rod 2 is inserted through a through hole 13a formed in the stopper mounting block 13.
The detected portion (metal) 14 formed at the tip faces the proximity switch 15 at a predetermined distance when the rod 2 is in a balanced state as shown.

Screw holes 13b and 13c are formed above and below the through hole 13a of the stopper mounting block 13,
Stopper screws 16 and 17 are screwed into these, respectively. The displacement width A of the rod 2 is determined by adjusting the screws 16 and 17. That is, the upper screw 16 determines the upper limit of rotation of the rod 2, and the lower screw 17 determines the lower limit of rotation of the rod 2. The displacement width A, or the upper and lower limits of rotation, are the characteristics of the proximity switch 15, the distance between this switch 15 and the detected part 14 of the rod 2, the distance between the fulcrums 4 and 5, and the distance between the fulcrum 4 and the operating rod 8. It is determined by taking into account the distance between

Although the embodiment of the present invention is configured as described above,
Next, this action, effect, etc. will be explained.

The figure shows the balanced state of the rod 2, but normally it rotates clockwise or counterclockwise around the fulcrum 4, and the tip of the rod 2 lightly touches either screw 16 or 17. It is in a stable condition. Now, suppose that the object to be measured is placed on the mounting plate 6.
The rod 2 rotates clockwise in the figure around the fulcrum 4. Proximity switch 15 detects this, current flows through coil 10 of actuator 7, and downward force F acts on actuating rod 8. That is, the rod 2 is rotated counterclockwise around the fulcrum 4.

When the object to be measured is placed on the mounting plate 6, the rod 2 attempts to rotate significantly clockwise, but the tip of the rod 2 collides with the lower end of the stopper screw 16, preventing further upward rotation. movement is suppressed. Proximity switch 1
5 detects that the rod 2 is above the balance position, and as a result, the coil 1 of the actuator 7
0 current is increased. The force F acting on the actuating rod 8 increases, and the rotational force of the rod 2 in the counterclockwise direction increases. That is, the rod 2 increases the rotational force toward the balance position.

When the rod 2 rotates downward beyond the balance position, the proximity switch 15 detects this,
The current flowing through the coil 10 of the actuator 7 is reduced. In this way, when the rod 2 assumes a balanced state as shown in the figure, the current flowing through the coil 10 is kept at a constant value. From this value, the weight of the object placed on the placing plate 6 is measured.

The present embodiment operates as described above, and has the following effects.

That is, according to this embodiment, since the bobbin 9 in the load measuring actuator 7 is made of aluminum containing a magnetic material, the portion 9a of the bobbin 9 facing the magnet 11 in the vertical direction is magnetized by the magnetic flux from the magnet 11. Most of the magnetic flux from the magnet 11 passes through the illustrated magnetic path to the yokes 12a, 1.
2b and 12c, the gap between the opposing portion 9a of the bobbin 9 and the magnet 11 is small, and since the bobbin 9 is made of a material containing a magnetic material,
The magnetic resistance is also small, and some magnetic flux also flows into the opposing portion 9a. Therefore, the opposing portion 9a has residual magnetism.

Therefore, when the coil 10 is not in use and no current is passed through it, even if it receives vibrations from the surroundings, a magnetic attraction force is exerted between the facing portion 9a of the bobbin 9 and the magnet 11, so that the vibrations are suppressed. Less impact. if,
When the rod 2 rotates due to surrounding vibrations, current will flow through the coil 10. However, according to this embodiment, such a problem can be prevented.
In addition, even when this weighing machine 1 is in use, that is, even when the rod 2 is rocking, the disturbing components caused by surrounding vibrations are absorbed by the above, so that the weighing machine 1 can be weighed accurately and quickly. The load on the plate 6 can be measured. Generally, bobbins are made of Bakelite, but this does not have this effect and is very difficult to handle.

Although the embodiments of the present invention have been described above, the present invention is of course not limited thereto, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the proximity switch 15 was used to detect the position of the rod 2, but a differential transformer or a photoelectric switch may be used instead.

Further, in the above embodiment, the mounting plate 6 suspended from the fulcrum 5 was used to load the weight of the object to be measured on the pole 2, but the load may be applied via another mechanism.

Further, in the above embodiment, in the actuator 7, the bobbin 9 is made of aluminum containing a magnetic material (for example, iron), but it may be made of a material containing another magnetic material or a pure magnetic material. Alternatively, only the facing portion 9a may be made of a magnetic material. Alternatively, a magnetic plate may be attached to the facing portion 9a.

Further, in the above embodiment, the permanent magnet 11 was used to provide a constant magnetic field, but a DC electromagnet may be used instead.

Further, in the above embodiment, the actuator 7 was applied to the weighing machine 1, but it can also be applied to other devices.

〔Effect of the invention〕

As described above, according to the load measuring actuator in a weighing machine of the present invention, it can be used stably without being affected by surrounding vibrations, and the accuracy and speed of weighing can be improved. can be improved.

[Brief explanation of drawings]

FIG. 1 is a side view of a ram type weighing machine according to an embodiment of the present invention, and FIG. 2 is a front view in the - line direction in FIG. 1. In the figure, 7...load measuring actuator, 9...bobbin, 9a...opposed portion, 10...coil, 11...magnet.

Claims (1)

[Claims] 1. A load to be measured is applied to one end of a ram which is rotatably supported on a fulcrum, and a load for balancing the ram is applied to the other end. A weighing machine is provided with a load measuring actuator consisting of a coil, which generates a force in a vertical direction through interaction between a current flowing through the coil and a magnetic flux from the magnet, and balances the ramrod by the force, A load measuring actuator characterized in that at least a portion of the bobbin that faces the magnet in the vertical direction is made of a material containing a magnetic material.