JP2539237B2 - Electronic scales - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electronic balance containing a calibration weight formed in a ring shape, and more particularly to an electronic balance having a pair of large and small ring-shaped calibration weights.

[Conventional technology]

When the weighing device is used for a long period of time, the display of the weight may be inaccurate due to slight looseness or slight deviation of the internal mechanism. The same thing occurs due to vibrations and the like during transportation of the weighing device. In this case, in order to calibrate the weight display of the weighing device to an appropriate value, it is necessary to adjust the display using a calibration weight whose accurate weight is known in advance.

The most commonly performed calibration work has been a method of placing a calibration weight on a weighing pan for calibration. However, in this method, the calibration weight is stored separately from the weighing device, and the calibration weight is taken out and used for each calibration, which is inconvenient to handle. Therefore, the calibration weight is stored in the weighing device in advance, and when calibration is required, the calibration weight is stored in the weighing device by an operation from the outside of the device (hereinafter referred to as "built-in weight"). There is provided a mechanism for performing calibration by transmitting the load of 1 to the load transmitting portion of the weighing object.

FIG. 5 shows a lifting mechanism for a built-in weight in an electromagnetic parallel weighing device (electronic balance), which is a conventional lifting mechanism known from JP-A-60-13224.

Reference numeral 50 in the figure is a built-in weight, and its planar shape is formed in an annular shape close to a perfect circle. The shape of the built-in weight is not necessarily specified, and various shapes such as a horseshoe shape and a bar shape are used depending on the arrangement state of the internal mechanism of the weighing device and the configuration of the built-in weight lifting mechanism. .
However, as a result of testing built-in weights of various shapes, the inventors have already confirmed that an annular calibration weight is ideal in terms of ease of calibration work and accuracy of calibration.

That is, if the built-in weight 50 is arranged so that the support shaft of the weighing pan 51, that is, the shaft center of the load transmission shaft and the center of the ring-shaped built-in weight 50, are arranged, the load of the built-in weight 50 is measured by the beam (weighing object). Member for transmitting the load to the weighing mechanism) 53 Support shaft
It can be added without being displaced from the axis of 52. Therefore, even if the load of the built-in weight is applied, no special stress is generated in the floating frame, and there is an advantage that the calibration can be easily performed without performing adjustment work such as four-corner adjustment.

Next, reference numeral 54 is a lift plate for lifting the built-in weight, and a cam 55
Rotation causes the built-in weight support to move around the fulcrum 54a.
It swings in the -Y direction.

In this conventional configuration, the lifting plate 54 is used in the normal weighing process.
The built-in weight support of is raised and fixed in the X direction, and the floating frame 53
For this, make sure that the load of this built-in weight 50 is not applied. If calibration is required, the cam 55 is rotated to lower the built-in weight support portion of the lift plate 54 in the Y direction, and the built-in weight 50 is placed on the floating frame 53 for calibration.

[Problems to be solved by the invention]

While the device configured as described above has good performance, it also has the following problems, and it is extremely difficult to secure a higher calibration accuracy and realize easier calibration work. Mechanism development is desired.

That is, in the device having the above-mentioned configuration, (1) In recent weighing devices, particularly in electronic scales such as a load cell type balance or an electromagnetic balance type scale, the load is electrically output so that the measurement mode can be changed according to the weighing object. A device is provided. For example, a weighing mode in which the minimum weighing is reduced but the minimum scale is reduced, and a weighing mode in which the minimum scale is large but the maximum weighing is increased are provided. There is.

In order to perform accurate calibration in such an apparatus, each built-in weight having a mass corresponding to each mode is required. On the other hand, the weighing device is required to be small and thin, and it is difficult to secure a sufficient space margin to equip one built-in weight, let alone have a margin to equip a plurality of built-in weights. Although there is a high need, there is no mechanism for raising and lowering a plurality of built-in weights corresponding to each mode.

(2) In the configuration shown in FIG. 5, the built-in weight is raised by the elevating plate 54 when the load of the weighing object can be measured.
Part of it is stored in the 56 recesses. If you change the layout of the weighing device or transport it in this state,
The built-in weight 50 may be displaced from a predetermined place due to vibration or inclination during movement. In such a situation, it may be impossible to perform accurate calibration at the time of calibration. Further, when the weighing device is transported with the built-in weight 50 placed on the floating frame 53 as it is, a load of several times the mass of the built-in weight is momentarily applied to the floating frame due to vibration or the like, and the floating weight is connected to the floating frame. There is a risk of destroying the weighing mechanism. Therefore, when the product is shipped or the device is moved, the built-in weight is taken out from the weighing device or a dedicated stopper is installed to protect the weighing mechanism. However, it is necessary to pay close attention to the work of loading the built-in weight again after the transfer, and even if such a caution is taken, the internal mechanism of the weighing device will be damaged when the built-in weight is remounted or the stopper is removed. Not a few accidents have occurred.

(3) Next, since the built-in weight 50 is lifted and lowered by the lift plate 54 that swings about the fulcrum 54a, the built-in weight 50 is actually lifted and lowered in the vertical direction along the axis of the support shaft 52. Instead of being performed, an arc is drawn around the fulcrum 54a. As a result, in order to accurately align the shaft center of the support shaft 52 and the center of the built-in weight 50 in the state of being mounted on the floating frame 53, the built-in weight lifting mechanism needs to be configured very precisely.

[Means for solving problems]

An electronic balance having two large and small annular built-in weights as built-in weights for calibration, the built-in weights are flat and large diameter large built-in weights, and flat and small diameter small built-in weights concentric with the large built-in weights. Both built-in weights share the axis with the support shaft for supporting the weighing pan provided on the floating frame that is part of the load transmission mechanism of the weighing device by the built-in weight support member that moves up and down along the load transmission direction. Are arranged in concentric circles so that the floating frame is provided with locking parts for locking these large and small built-in weights at different locking heights, and large and small built-in weights are selected by raising and lowering the built-in weight support member. The electronic scale is configured so that it can be added to the floating frame.

[Action]

The built-in weight lifting mechanism using the cam mechanism moves up and down the built-in weight support member, a portion of which is in contact with and locked by the cam. The built-in weight support member moves up and down along a support pin whose load transmission shaft and its axis are parallel to each other, so that the built-in weight can be moved up and down while holding the built-in weight in a horizontal state.
Of the floating frames, the lightweight small built-in weight and the large heavy built-in weight are brought into contact with each other at different heights so that when the built-in weights are lowered, the lightweight built-in weight is first placed on the floating frame. Then, calibrate in the precision measurement mode in this state. Further, if the support member is further lowered, the large-weight built-in weight is also placed on the floating frame, and calibration in the large-weight measurement mode is performed.

〔Example〕

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

1 and 2 specifically show the built-in weight lifting device. In the figure, reference numeral 1 indicates a large-diameter (large-weight) built-in weight (hereinafter referred to as "large built-in weight"), and 2 is a small-diameter small (lightweight) built-in weight (hereinafter referred to as "large built-in weight"). "Small built-in weight").

As is clear from the figure, the large and small built-in weights 1 and 2 are formed in a circular donut-shaped annular shape (ring shape) in plan view, and both built-in weights 1 and 2 are axially (center) by a support member described later. Are arranged concentrically so that they are common. Each of the built-in weights 1 and 2 is formed thin so that the upper and lower annular end surfaces are close to each other. That is, both built-in weights 1 and 2 are formed flat so that they can be placed in a very limited space of the weighing device. Reference numeral 3 is a support member that supports these built-in weights 1 and 2 and moves them up and down.
Reference numerals 3a, 3b, and 3c denote built-in weight support arms extending from the support member frame 3d having a substantially U-shape in plan view to the inside of the frame.

The large and small built-in weights 1 and 2 are the support arms.
By being supported by 3a, 3b, 3c, they are arranged concentrically so that their axes are common, and the common axis coincides with the axis of the load transmission shaft that transmits the load of the weighing object to the beam side. Arranged to do so. Further, when the built-in weights 1 and 2 are supported by the support member 3, the upper end surface of each built-in weight and the upper end surface of the support member 3 are located substantially on the same plane (see FIG. 1, FIG. (See FIG. 4), the built-in weight lifting mechanism including these built-in weights 1 and 2 is formed to be extremely flat, and is configured so as to be easily incorporated in the limited space of the weighing device.

Next, at the four corners of the frame 3d of the support member 3, support pins 4a,
4b, 4c and 4d are inserted. The lower end of this pin is fixed to the main body of the weighing device, and the support member 3 extends along this pin along the axial center of the load transmission shaft, and each built-in weight 1,
It is designed to move up and down while holding 2 horizontally. Reference numerals 3e and 3f denote elevating projecting pieces that are projected at the opposite sides of the frame 3d, and the elevating mechanism comes into contact with the elevating projecting pieces 3e and 3f so that the supporting member 3 and The built-in weights 1 and 2 supported by the support member 3 are moved up and down.

 Next, the lifting mechanism of the support member will be described.

A rotating shaft 5 is rotated by a geared motor 6, and a first cam 7 and a second cam 8 are provided for the rotating shaft 5. Reference numeral 9 is a bearing fixed to the main body of the weighing device. Of the two cams provided on the rotary shaft 5, the first cam 7 is in contact with the lower surface of the lifting projection 3f of the support member 3,
Another second cam 8 is in contact with the lower surface of one end of the first oscillating plate 10 forming a part of the lifting motion transmission mechanism. The swing plate 10 swings in the X1-Y1 direction by a fulcrum 11. Next, reference numeral 12 is a second oscillating plate which is arranged so as to be substantially perpendicular to the first oscillating plate 10 and oscillates in the X2-Y2 direction by a fulcrum 13. The end of the side that contacts the moving plate is arranged so as to be in contact with the lower surface of the first swing plate 10.

In Fig. 3, the built-in weight lifting mechanism is omitted and each built-in weight 1
2 and 2 and the positional relationship of the floating frame for load transmission. 14 in the figure
Indicates a floating frame that forms a part of the load transmission mechanism that transmits the load of the weighing object to the load measurement mechanism. 14a is a notch for mounting and supporting the large internal weight 1 formed on the floating frame 14, and 14b is a notch for mounting and supporting the small internal weight 2. Among these notches, the bottom of the notch 14b that supports the small built-in weight 2 is formed to be higher than the position of the notch 14a for supporting the large built-in weight by h. By the way, the stroke of the vertical movement of the support member 3 is 5 to
A height of about 7 mm is sufficient, and therefore the height difference h may be as small as about 2 to 3 mm.

 Next, the operating state of the above-mentioned component device will be described.

First, a description will be given of a state in which the built-in weights 1 and 2 are raised and no load is applied to the floating frame, that is, a measurable state of the weighing object.

By operating the geared motor 6, the first and second cams 7 and 8 are rotated via the rotary shaft 5. First, the first cam 7 will be described. The rotation of the first cam 7 makes contact with the cam 7. The protrusion 3f is pushed upward in the X3 direction. Similarly, one of the ends of the up-and-down motion transmission mechanism pushes up the cam contact end of the first rocking plate 10 in contact with the second cam 8.
As a result, the opposite end is lowered in the Y1 direction about the fulcrum 11, and the end of the second rocking plate 12 is pushed down in the same direction. By this operation, the end of the second rocking plate 12 on the side of the protruding piece 3e rises in the X2 direction and pushes the protruding piece 3e in the same direction. That is, the protrusions 3e, 3f are simultaneously pushed up in the same direction by the rotation of the cams 7, 8. By this operation, the support member 3
Rise along the pins 4a to 4d, and the built-in weights 1 and 2 supported by this support member rise while maintaining a horizontal state. Then, the rotation of the cam is stopped at the raised position, and each built-in weight is supported by the support member 3. As a result, the loads of the internal weights 1 and 2 are all supported by the support member 3, and only the load of the weighing object placed on the weighing pan 15 is transmitted to the floating frame 14. Reference numeral 16 in FIG. 4 is a weighing dish.
A support shaft for supporting the load 15, a load transmission shaft for transmitting the load of the object to be weighed, and a common shaft center of the built-in weights 1 and 2 arranged concentrically as shown in FIG. It is also configured to be common with the axis of the shaft 16.

 Next, the operating state when performing calibration will be described.

By operating the geared motor 6, the first and second cams 7 and 8 are rotated again. As a result, the support member 3 is gradually lowered by the operation opposite to the above-described rising operation. When the position of the supporting surface SL (see FIG. 6) of each of the built-in weights 1 and 2 on the support member 3 reaches the position of L1 shown in FIG. 4 by this descending, the lower surface of the small built-in weight 2 becomes the small size of the floating frame 14. It is placed in the notch 14b for the built-in weight, and only the load of the small built-in weight 2 is transmitted to the floating frame 14. When the support member 3 is further lowered and the position of the support surface SL reaches the position of L2, the large built-in weight 1 is placed in the notch 14a of the floating frame 14, and both weights 1 and 2 are attached to the floating frame 14. Will be transmitted.

Here, in the case of performing calibration in the precise weight measurement mode of the weighing device, the position of the support surface SL of the support member 3 is positioned between L1 and L2, and only the small built-in weight 2 is placed on the floating frame 14. . As a result, accurate calibration can be performed with the small built-in weight 2 having a weight suitable for calibration in the precision weight measurement mode. When performing calibration in the large weight measurement mode, the support member is lowered so that the support surface SL is below the position of L2, and the calibration is performed by the total load of the small built-in weight 2 and the large built-in weight 1. During the above operation, since the built-in weights 1 and 2 descend vertically by the support member 3, the axes of the built-in weights 1 and 2 and the axis of the load transmission shaft 16 are always aligned. By placing the weight, no special stress is applied to the floating frame, and accurate calibration can always be performed.

As described above, the configuration of the present invention includes a large built-in weight and a small built-in weight.
Although the case of raising and lowering one type of built-in weight has been described as an example, it goes without saying that it is configured to raise and lower one built-in weight.
It goes without saying that a configuration in which three or more built-in weights are sequentially mounted on the floating frame is also included in the technical configuration of the present invention.

〔effect〕

As described above, according to the present invention, the loads of a plurality of built-in weights can be selectively added to the load transmission mechanism. Therefore, the weighing device can be appropriately selected by selecting the load of the built-in weight to be added to the load transmission mechanism. It is possible to always perform proper calibration according to the weight measurement mode of.

In addition, since each built-in weight is formed flat and arranged concentrically, even if a plurality of built-in weights are stored and arranged, it can be stored if there is a space where the conventional annular built-in weight lifting mechanism can be stored, A plurality of built-in weights can be stored without increasing the thickness and size of the weighing device.

In addition, the built-in weight lifting mechanism raises and lowers the built-in weight support member, and the built-in weight support member moves up and down along a support pin whose load transmission shaft and its axis are parallel, so that the built-in weight is placed in a horizontal state. Since the configuration is such that the built-in weight is placed on the load transmission part such as a floating frame, the center of load addition and the center of load transmission of the weighing object are aligned, making calibration easy and extremely easy. Can be done accurately.

Furthermore, since the support member is supported by a plurality of strong support arms, the built-in weight can be reliably held even if vibration or large stress is applied when the weighing device is moved, etc. There is no need to take out the weight or equip a special stopper, etc., and the weighing device during transfer is extremely easy to handle.
In addition, various effects such as the risk of an accident such as damage to the internal mechanism due to reattachment of the built-in weight and removal of the stopper as in the conventional device are eliminated.

[Brief description of drawings]

FIG. 1 is a perspective view of a pair of large and small annular built-in weights and a built-in weight lifting device for lifting and lowering each built-in weight, and FIG. 2 is a built-in weight lifting device stored in a weighing device. FIG. 3 is a plan view of the built-in weight and the floating frame showing the arrangement state of the built-in weight and the floating frame, and FIG. 4 is A of FIG.
FIG. 5 is a cross-sectional view taken along line A, FIG. 5 is a side view of an elevator showing a conventional built-in weight lifting mechanism, and FIG. 6 is a cross-sectional view showing how the built-in weight is placed on the arm of the built-in weight support member. 1 …… Large built-in weight 2 …… Small built-in weight 3 …… Built-in weight support members 3a, 3b, 3c …… Supporting member arm 3d …… Supporting member frame 3e, 3f …… Supporting member lifting protrusions 4a, 4b , 4b ...... Support member support pin 5 ...... Rotating shaft 6 ...... Geared motor 7 ...... First cam 8 ...... Second cam 10 ...... First oscillating plate 12 ...... Second oscillating plate 14 ...... Floating Frame 16 ... Load transmission shaft

Claims (2)

(57) [Claims] 1. An electronic scale for calibrating by incorporating a ring-shaped weight as a calibration weight and adding the built-in weight to a floating frame of a load transmission mechanism, wherein the ring-shaped built-in weight is a flat large-sized built-in weight. And a small built-in weight having a flat and small diameter, both built-in weights are supported by built-in weight supporting members that move up and down along the load transmitting direction so that the small built-in weight is stored in the internal space of the large built-in weight. Locking parts for locking these large and small built-in weights are provided at different heights, and the built-in weight support members can be raised and lowered to selectively add large and small built-in weights to the floating frame. An electronic scale configured as possible. 2. The built-in weight support member is configured to vertically move up and down along a plurality of vertically fixed support pins, and the built-in weight support member lifting mechanism is connected to the cam mechanism and the cam mechanism. And a first oscillating mechanism which is formed on the internal weight supporting member and which contacts the protruding piece, and a first oscillating shaft which is coaxial with the first cam and which forms a part of the vertical movement transmitting mechanism. The lifting / lowering motion transmission mechanism includes a first cam and a second cam that is in contact with the moving plate.
And a second swing plate that swings by engaging the swing plate,
The built-in weight support member is vertically moved by the vertical movement by the rotation of the first cam transmitted to the protrusion and the vertical movement by the rotation of the second cam transmitted to another protrusion via the vertical movement transmission mechanism. The electronic scale according to claim 1, wherein the electronic scale is configured to be moved up and down.