JP2000337954A - Electronic balance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect the mechanism in a balance by fixing a sample mount pan through easy operation without damaging the electronic balance in conveyance. SOLUTION: A pan fixation base composed of a guide shaft 22 having a female screw thread and a slider 23 which can move up and down is provided between a case upper part 11 and the sample mount pan 20. To protect the mechanism in the electronic balance, for example, when the electronic balance is conveyed, the slider 23 is moved up to abut against the reverse surface of the sample mount pan 20 and the slider is fixed to the guide shaft 22 at the position. At this time, the sample mount pan 20 is in contact with the pan fixation base 21 while no unreasonable force is applied to the internal mechanism of the balance, so a fixing bolt 29 is threadably engaged with the female screw in this state from above the sample mount pan 20 and fixed to the pan fixation base 21. Consequently, the sample mount pan 20 never vibrates upward and downward in conveyance, etc., and the internal mechanism of the balance is not broken.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic balance,
In particular, the present invention relates to an electronic balance having a mechanism for protecting a mechanically fragile portion of the electronic balance during storage or transportation of the electronic balance.

[0002]

2. Description of the Related Art Generally, an electronic balance is configured such that a dish on which a sample whose mass is to be measured is placed or a dish receiver having a structure for receiving the dish is inserted into an engagement portion formed in a load sensitive portion inside the balance. The dish is often removable so that the internal mechanism is not affected by the vibration of the dish during transportation. However, in the case of an electronic balance that measures a large weight, the equivalent of a plate or a pan holder is quite heavy, and when it is firmly fixed to the load-sensitive part and cannot be easily attached / detached to reduce error factors during measurement. There is. In such a case, every time the electronic balance is transported, it is troublesome to remove the very heavy pan or the pan receiver and attach it again after transporting.

[0003] Even if the electronic balance has a structure in which a plate and a plate receiver can be attached and detached, it may take time to adjust four-corner errors when a plate or the like is attached to the balance body in a high-precision electronic balance. . Furthermore, when attaching another component such as a sample receiver to the plate or the plate receiver, a large force may be applied to the plate or the like during the mounting operation.

[0004]

The balance mechanism of an electronic balance is configured such that the weight of the sample to be measured and the electromagnetic force generated therein are balanced by a bar supported by an elastic fulcrum. Therefore, the plate on which the sample is placed can be moved up and down with a small force in the state where normal measurement is performed.Therefore, when transporting this electronic balance or attaching parts to the plate, vibration may occur. Therefore, it is necessary to protect the sample mounting plate from moving up and down to break the elastic fulcrum and other fragile parts inside the balance.

In general, when transporting, it is sufficient to remove the plate from the main body of the electronic balance and pack it separately so that a large-mass object is not connected to the fragile portion inside the balance. In the case of a structure that cannot be removed, this operation was very troublesome. In addition, even if the plate can be removed relatively easily, it may not be necessary to remove the plate as much as possible in order to save adjustment when re-attaching the plate.

[0006] The present invention has been made in view of such circumstances, and is intended for use in an electronic balance in which the structure for removing the sample mounting plate is difficult to remove, or even when the sample mounting plate is not removed, during transportation. An object of the present invention is to provide an electronic balance that can easily fix a sample mounting plate and protect a mechanism inside the balance without damaging the electronic balance during work.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an electronic balance having a case having a built-in load-sensitive part and a sample mounting plate disposed above the case. A guide shaft extending toward
A case in which a slide that can move up and down along the guide shaft and a dish fixing base including a slide fixing means for fixing the slide to the guide shaft is arranged in the case to protect the load-sensitive portion. Moves the slider upward until it hits the bottom surface of the sample mounting plate, and at that position, fixes the slider to the guide shaft by the slider fixing means, and in this state, the sample mounting plate And a plate fixing means for fixing the plate to the plate fixing table.

In the electronic balance of the present invention, a plate fixing table is provided on a case below the sample mounting plate, and the sample mounting plate having a structure that cannot be easily removed is fixed to the plate mounting table to convey the electronic balance. Prevents the balance mechanism from being damaged by vibrations that occur at times. The dish fixing base includes a guide shaft extending in the up-down direction and a slide that can slide up and down along the shaft. The slide can be fixed to the guide shaft at any position on the guide shaft.

When measuring the mass of a sample using the electronic balance of the present invention, the above-mentioned slider is lowered and fixed to the guide shaft, and a gap is provided between the plate fixing table and the sample mounting plate. To be able to do. In this state, the plate fixing table does not restrict the movement of the sample mounting plate at all, so that the mass can be measured as usual. If you want to protect the internal mechanism of the balance, for example, when transporting an electronic balance, move the above slider upward and abut the lower surface of the sample mounting plate, and slide the slider at the guide shaft at that position. To be fixed. At this time, the sample mounting plate is in contact with the plate mounting base without overloading the internal mechanism of the balance. In addition, the sample mounting plate does not vibrate up and down, and the internal mechanism of the balance is not destroyed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of the electronic balance of the present invention as a longitudinal section. In the electronic balance 1 of the present invention, a balance mechanism for detecting a load and a case 11 covering the whole of them are fixed on a base 13 serving as a base. Two beams extend horizontally from the fixed column 2 fixed to the base 13, and the movable column 3 is connected to the end thereof. The upper beam 4 and the lower beam 5 which are two beams are parallel to each other, and the thin portions 6 are provided near the fixed column 2 and the movable column 3 of both beams, respectively.
Are formed, and the thin portion is made flexible to constitute a roberval mechanism. This roberval mechanism enables the movable column 3 to move in parallel only in the vertical direction. One end of the balance bar 7 supported from below by the elastic fulcrum 8 is connected to the movable column 3 via a connecting member 9, and an electromagnetic force generating unit 10 is provided near the other end of the balance bar 7.
Is arranged. Take-out part 12 extending from movable column 3
Is mounted with a sample mounting plate 20.

When a sample whose mass is to be measured is placed on the sample mounting plate 20, the load is applied to the movable column 3 via the take-out portion 12, and the force is applied to one end of the balance bar 7 via the connecting member 9. (Left end of FIG. 1). Then, the balance bar 7 tries to tilt in the direction in which the movable column 3 moves downward with the elastic fulcrum 7 as a fulcrum. The displacement is detected by a displacement meter (not shown) and the other end of the balance bar is set so that the displacement becomes zero. A force is generated by the electromagnetic force generating unit 10 installed near (the right end in FIG. 1) and the balance bar 7 is controlled so as not to tilt. At this time, the load applied to the left end of the balance bar 7 and, hence, the mass of the sample placed on the sample mounting plate 20 are measured from the current value flowing through the coil built in the electromagnetic force generating unit 10.

The above-mentioned elastic fulcrum 8 is made of a leaf spring having a thin portion which is partly thinned in order to bend easily. This is because the fulcrum needs to be able to freely bend left and right with a small force. The connecting member 9 also has a thin portion to absorb the difference between the vertical movement of the movable column 3 and the movement of the end of the balance bar 7, so that an unreasonable force is not applied to the balance bar 7. Further, as described above, the thin portions 6 are also formed on the upper and lower beams. These thin portions are mechanically fragile portions, and are also portions that are easily damaged by large vibrations or excessive external force applied to the sample mounting plate 20.

In the electronic balance of the present invention, in order to protect a fragile mechanism inside the balance from vibrations during transportation or the like, a dish fixing means (FIG. 1) for fixing the sample mounting dish 20 to a case covering the internal mechanism of the balance. A section). 2 and 3
FIG. 2 is a diagram illustrating an enlarged part A of FIG. 1. FIG. 2 shows a state in which the sample mounting plate 20 is not fixed and is used for measuring the mass as usual, and FIG. 3 is for protecting the internal mechanism of the balance from vibration or the like when the balance is transported. It is a figure showing the state where the sample mounting plate was fixed to the plate fixing stand. In addition,
The number of dish fixing tables need not be limited to two as shown, but at least one is sufficient and three or more may be used.

In FIG. 2 and FIG. 3, a plate fixing base 21 is formed in a cylindrical guide shaft 22 formed on the upper part of the case 11.
And a cylindrical slider 23 fitted so as to be able to move up and down around the guide shaft 22, a spring 25 acting to push the slider 23 upward along the guide shaft, and a suitable slide. It consists of a fixing screw 24 which is a slider fixing means for fixing to the guide shaft at the position. A female screw 27 is cut at the center of the guide shaft.
A through hole 26 is formed at a position corresponding to the position directly above the 0 guide shaft.

When measuring the mass, as shown in FIG. 2, the slider 23 is fixed by a fixing screw 24 at a position pressed down along the guide shaft 22, and An appropriate gap 28 is formed between the lower surface and the upper ends of the guide shaft 22 and the slide 23. In this state, the sample placing plate 20 can freely move up and down independently of the plate fixing table 21, so that the mass of the sample placed on the plate can be measured as usual.

When it is necessary to protect the internal balance mechanism as in the case of transporting the electronic balance, the sample mounting plate 20 is fixed to the plate fixing table 21 in the state shown in FIG. First, the fixing screw 24 is loosened with no load placed on the sample mounting plate 20 without any load. Then, the slide 23 is operated by the spring 25.
Is pushed upward, and the upper end of the slider 23 is
0 is pressed against the lower surface. Fixing screw 2
4 to fix the slide 23 to the guide shaft 22. Next, when the bolt 29 is inserted and screwed into the female screw 27 formed on the guide shaft 22 from above the sample mounting plate 20 through the through hole 26, the sample mounting plate 20 is firmly fixed to the plate fixing base 21. .

The slide fixing means for fixing the slide 23 to the guide shaft 22 will be described in more detail. FIG. 4 is a view showing a preferred example of the slider fixing means, and is a cross-sectional view when the guide shaft 22 and the slider 24 fixing screw 24 are cut along a horizontal plane. The slider 23 has a substantially rectangular cross section, a circular space in the center where the guide shaft 22 enters, and a part of the slit 32.
Is provided. A through hole for passing the fixing screw 24 is formed on one side of the portion sandwiching the slot 32, and a female screw 33 screwed with the fixing screw 24 is cut on the other side. When the fixing screw 24 is tightened in the combined state as shown in FIG. 4, the slider 23 is strongly pressed by the cylindrical guide shaft 22, and the slider 23 is fixed to the guide shaft 22. If the fixing screw 24 is loosened, the slider 23 can slide freely along the guide shaft 22 (in the direction perpendicular to the paper surface).

FIG. 5 is a view showing another example of the slider fixing means, and is a cross-sectional view taken along a horizontal plane. The slider 23 has a cylindrical shape, and has a female screw threaded with a fixing screw 24 at one location. The guide shaft 22 has a cylindrical shape, and a part thereof has a flat surface 34 formed thereon. When the fixing screw 24 is tightened in the combined state as shown in FIG. 5, the slider 23 is fixed to the guide shaft 22, and when loosened, the slider 23 can slide freely along the guide shaft.

In the above embodiment, the guide shaft 2
Although the 2 and the slider 23 are cylindrical and cylindrical, they need not have a circular cross section as long as they can move freely in the vertical direction, and may have a square or other shapes. The above-mentioned spring 2
Reference numeral 5 denotes a coil-shaped push spring, which pushes up the slide to improve workability, but is not necessarily essential, or may be a spring of another shape. Further, the means for fixing the slider 23 to the guide shaft 22 is not limited to the fixing screw 24 as described above, but may be a simple pin. In this case, a hole or the like for engaging the pin may be formed on the guide shaft. Bolt 29
If a wing bolt or the like is used so that the worker can tighten it by hand, workability is good and convenient.

[0020]

According to the electronic balance of the present invention, the inside of the balance mechanism can be prevented from being damaged by vibration generated during transportation or work by fixing the sample mounting plate to the plate fixing table. This dish fixing base consists of a guide shaft that extends in the vertical direction and a slider that can slide up and down along the axis.The slider can be fixed to the guide shaft at any position on the guide shaft. The workability of fixing the plate is good, and the balance mechanism can be easily protected with little labor.

[Brief description of the drawings]

FIG. 1 is a view showing a vertical cross section of an electronic balance of the present invention.

FIG. 2 is a diagram showing a state at the time of mass measurement near a dish fixing base, which is a main part of the present invention.

FIG. 3 is a diagram showing a state of protection around a dish fixing base, which is a main part of the present invention.

FIG. 4 is a view showing an example of a slider fixing means.

FIG. 5 is a view showing another example of the slider fixing means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electronic balance 2 ... Fixed pillar 3 ... Movable pillar 4 ... Upper beam 5 ... Lower beam 6 ... Thin part 7 ... Balance bar 8 ... Elastic fulcrum 9 ... Connecting member 10 ... Electromagnetic force generation part 11 ... Case 12 ... Take-out part 13 ... Base 20 ... Sample mounting plate 21 ... Dish fixing stand 22 ... Guide shaft 23 ... Slider 24 ... Fixing screw 25 ... Spring 26 ... Through hole 27 ... Female screw 28 ... Gap 29 ... Bolt 31 ... Through hole 32 ... Slotting 33 ... female screw 34 ... flat surface

Claims (1)

[Claims] 1. An electronic balance having a case having a built-in load-sensitive part and a sample mounting plate disposed above the case, a guide shaft extending upward from the case,
A case in which a slide that can move up and down along the guide shaft and a dish fixing base including a slide fixing means for fixing the slide to the guide shaft is arranged in the case to protect the load-sensitive portion. Moves the slider upward until it hits the bottom surface of the sample mounting plate, and at that position, fixes the slider to the guide shaft by the slider fixing means, and in this state, the sample mounting plate An electronic balance, comprising: dish fixing means for fixing the plate to the dish fixing table.