JPH0572965B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic balance, and more particularly to an electronic balance configured to accurately transmit the load of an object to be weighed to an electromagnetic part.

[Conventional technology]

Electromagnetic balance type weighing devices called electronic balances are capable of achieving high measurement accuracy, and the fields of their use have recently been expanding.

The structure of a conventional electronic balance, centering on the electromagnetic part, is shown as follows using FIG.

In the figure, reference numeral 1 is an upper sub-rod, 2 is a lower sub-rod arranged parallel to the upper sub-rod 1, and one end of both is a frame 3 which is a fixed member constituting the main body of the electromagnetic section.
They are connected to each other via leaf springs 4 and 5, respectively.

On the other hand, a front arm 6 is connected to the other ends of these upper and lower secondary rods 1 and 2 via leaf springs 7 and 8 similar to those described above, and these frame 3, upper secondary rod 1,
The front arm 6 and the lower sub-rod 2 constitute a roberval mechanism.

The other frame 3 is a fixed member (non-operating member).
The electromagnetic part itself is housed inside. This electromagnetic part main body includes a yoke 9, a magnet 10 disposed inside the yoke 9, a pole piece 11 located above the magnet 10, and a pole piece 11.
It consists of a coil 12 located around the .
Further, the coil 12 is wound around a bobbin 13. This bobbin 13 is integrally fixed to a beam 14 that forms a part of a load transmission mechanism that transmits the load of the weighed object to the electromagnetic section.
It is beginning to be displaced along with the Also beam 1
4 itself is connected to the frame 3 via a leaf spring 15, and is configured to swing about the leaf spring 15 as a fulcrum.

In the above configuration, when an object to be weighed is placed on the weighing pan 16, the load is transmitted to the Roberval mechanism via the front arm 6. At the same time, this load is also transmitted to the beam 14 via the suspension band 17, and this load acts to rotate the beam 14 using the leaf spring 15 as a fulcrum. Since a coil 12 is further integrally provided on the beam 14 via the bobbin 13, this coil 12 also connects to the beam 14.
try to move along with it.

On the other hand, the displacement of the beam 14 is detected by a position sensor (not shown), and power is supplied to the coil 12 so as to balance the beam 14, and the load of the object to be weighed is calculated from the amount of supplied power.

[Problems to be solved by the present invention]

In the conventional structure of the electromagnetic section shown above, reference numeral 18 is a wiring which is fixedly installed between the coil 12 whose position is displaced by a load and the flume 3 side which is a fixed part where such displacement does not occur. The circuit board 19 is arranged so as to straddle the circuit board 19, and the two are electrically connected.

This wiring 18 is a general wiring in which a conductor such as a metal wire is placed in the center and the surrounding area is covered with an insulating material such as synthetic resin, but the physical properties of this wiring have a delicate effect on the operation of the beam 14. It will have an impact.

That is, one end of the wiring 18 is connected to the circuit board 19 side, which is a non-operating part, and the other end is connected to the coil 12 on the beam 14 side, which is activated and displaced by a load, so that the wiring 18 is connected with the beam 14 as the center. As a result, it is incorporated into the constructed load transmission mechanism and inadvertently forms part of the mechanical configuration of the same load transmission mechanism. As a result, when the beam 14 attempts to displace, the physical properties or mechanical properties (hereinafter referred to as "physical properties") of the wiring 18 act as a force that prevents the beam from being displaced.

The wiring 18 has the elasticity and toughness of the metal wire that is the conductive part.
It has unique physical properties due to physical properties such as flexibility and similar physical properties of the synthetic resin that is the insulating coating formed around the metal wire. This physical property acts to prevent displacement of the beam 14 or to restrict displacement in a certain direction, so that the displacement of the beam no longer corresponds to the load of the weighing object applied thereto, and as a result, the accurate weight Measurement may become difficult.

In particular, physical properties such as elasticity and flexibility of synthetic resins that serve as insulation coatings change relatively significantly due to changes in temperature, and these changes progress over time.
It is also virtually impossible to specify the physical properties of the wiring 18 as a weight measurement correction value.

Note that it is possible to reduce the influence of the physical properties by making the wiring 18 thinner; however,
Since it is necessary to supply a certain amount of electricity to the coil 12, there is a limit to the thinning of the wire, and it does not completely solve the problem.

In addition, if electronic balances with even higher precision become available in the future, a mechanism will be configured to displace the beam 14 with an even smaller force. The impact of this will become relatively large, and the impact will become increasingly impossible to ignore.

[Means for solving problems]

The present invention was constructed in view of the above problems, and includes a coil connected to the beam side, which is the displacement side,
When connecting the circuit board fixed on the fixed side of the frame by wiring, the coil and the circuit board are connected with two wirings, and one wiring connects the coil and the leaf spring that is the fulcrum of the beam. , the other wiring connects the leaf spring and the circuit board, thereby electrically connecting the coil and the circuit board via the leaf spring, and the wiring itself being physically separated by the leaf spring. This is an electronic balance configured so that the physical properties of the wiring do not affect the displacement of the beam.

[Effect]

With the above configuration, one wiring is displaced together with the beam, and the other wiring is placed in an inactive area that does not originally affect the beam displacement, so the physical properties of the wiring are determined by the displacement of the beam. Since the beam is displaced only by the load applied to the object to be weighed, it is possible to accurately measure the load of the object to be weighed.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to the drawings.

In FIGS. 1 to 3, the electromagnetic section main body includes a yoke 9 disposed within the frame 3 and a magnet 1 disposed within the yoke 9, as in the conventional structure.
0, a pole piece 11 located above the magnet 10, and a coil 12 formed by being wound around the pole piece 11. Further, the coil 12 is wound around a bobbin 13, and this bobbin 13 is connected to the beam 1.
4 and is configured to move up and down together with the beam 14. The beam 14 is connected to the frame 3 by a leaf spring 15, and is configured to swing about the leaf spring 15 as a fulcrum.

Reference numeral 20 denotes a wiring whose both ends are connected to the coil 12 and the beam-side attachment portion of the plate spring 15 serving as the fulcrum. Figures 2 and 3 show details of this connection. The wiring 20 is electrically connected to the leaf spring 15 via a connecting means such as a screw 22. Note that the leaf spring 12 itself is made of steel, etc.
It is originally formed from a good conductor of electricity. Further, the beam 14 and the wiring 20 are insulated by an insulating member 21.

On the other hand, on the side of the frame 3 which is the non-operating part, another wiring 23 is electrically connected to the leaf spring 15 using a connecting means such as a screw 24, similar to the wiring 20 described above. The other end of this wiring 23 is connected to a circuit board 19, and the weight of the weighed object is displayed through a circuit formed on this board. Note that the leaf spring 15 and the frame 3 are insulated by an insulating member 21 as in the case of the beam 14. Also, these wirings 20, 23
Like the above-mentioned wiring, the wiring itself is a normal wiring made of a conductor wire covered with an insulating material.

In the above configuration, when a load of an object to be weighed is applied to the weighing pan 16, the load is transmitted to the Roberval mechanism via the front arm 6. This load is transmitted to the beam 14 via the front arm 6 and the suspension band 17, and the beam 14 is supported by the leaf spring 1 which is the fulcrum.
A force is applied so that it rotates around 5. This force is further transmitted to the coil 12 via the bobbin 13 connected to the beam 14 and tends to displace this coil 12.

In response to this, the displacement of the beam 14 is detected and electromagnetic force is generated to cancel this displacement, but all inputs and outputs to the coil 12 are performed via the wiring 20, the leaf spring 15, and the wiring 23. . In this case, since the coil 12 is integrated with the beam 14 via the bobbin 13, the wiring 20 connecting the coil 12 and the leaf spring attachment part of the beam 14 is completely integrated with the beam when the beam is operated. It will change and be displaced.

Therefore, physical properties such as elasticity, toughness, and flexibility of the wiring 20 do not affect the operation of the beam 14 at all. Note that since the wiring 23 is arranged on the frame 3 side, which is originally fixed, the above-mentioned problem does not occur from the beginning. Also, the leaf spring 15 which is the current-carrying part
As mentioned above, it is made of a good conductor and has a sufficiently large cross-sectional area compared to the amount of electricity to be energized, so it has been confirmed that problems such as heat generation do not occur when energized.

〔effect〕

The present invention has a structure in which the coil, which is fixedly connected to the beam, and the leaf spring attachment part of the beam are connected by wiring, so that the wiring is displaced integrally with the beam. Physical and mechanical properties such as elasticity and flexibility do not affect the operation of the beam at all, and the accuracy of the weighing device can be improved.

In particular, as the measurement accuracy of the weighing device improves, the physical influence of the wiring on the mechanism increases.As the accuracy of the weighing device improves in the future, this configuration will make a major contribution to improving this accuracy. becomes possible.

In addition, the present invention can basically be implemented by changing the wiring attachment point, and can be implemented without changing the design of the mechanical configuration of the load transmission mechanism itself, so it can be implemented even with conventional equipment, making it extremely useful. It is widely and economically available.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the electromagnetic part of an electronic balance showing an embodiment of the present invention, Fig. 2 is a view taken along line A-A in Fig. 1, and Fig. 3 is a cross-sectional view taken along line B-B in Fig. 2. , FIG. 4 is a sectional view of the electromagnetic part of a conventional electronic balance. 3... Frame, 12... Coil, 14... Beam, 15... Leaf spring, 19... Circuit board, 2
0,23...Wiring.

Claims (1)

[Claims] 1 A coil constituting a part of the electromagnetic part is integrally fixed to a beam that transmits the load of the weighed object to the electromagnetic part, and the beam is connected to the fixed part with a leaf spring connected at one end to the fixed part as a fulcrum. In an electronic balance configured to undergo oscillating displacement and to measure the load of an object to be weighed by balancing the displacement of this beam in an electromagnetic section, the coil 1
2 is connected to one end of the wiring 20, and the other end of the wiring 20 is connected to the end of the leaf spring 15 forming the fulcrum on the beam 14 connection side, so that the wiring 20 is integrally connected to the beam 14 and the coil 20. placed,
Another wiring 23 is connected to the fixed part side end of the leaf spring 15, and the other end of the wiring 23 is connected to the circuit board 19.
By configuring the coil 12 and the circuit board 19 to be connected to each other, the coil 12 and the circuit board 19 are electrically connected via the leaf spring 15, and the coil 12 and the circuit board 19 are
By configuring the wiring connecting beam 1 to beam 1 to be physically separated by this leaf spring 15,
4. An electronic balance characterized in that the physical and mechanical properties of the wiring, such as flexibility, toughness, and elasticity, do not affect the displacement of the beam during the displacement of the beam.