JP3005442U - electronic balance - Google Patents

Abstract

(57) [Summary] [Purpose] Providing an electronic balance that enables highly accurate adjustment of the four corners. [Structure] The four-corner adjustment mechanism 20 includes a spring 21 and an adjustment bolt 22.
And a threaded rod 23, and is provided close to the mounting portion of the leaf spring 6 interposed between the upper sub-bar 2 and the frame 1. A fixed frame portion 1b and a movable frame portion 1c are provided on the upper side of the frame 1. The spring 21 is interposed between the fixed frame portion 1b and the movable frame portion 1c. The adjusting bolt 22 is formed in a hollow shape and has a male screw 24
And the internal thread 25 is engraved on the inner circumference, and the thread pitch of the screws 24 and 25 is
It is larger than 25. The female screw 25 is formed so as to be screwed with the screw rod 23. The movable frame portion 1c is provided with a female screw hole 27 that can be screwed into the male screw 24. The fixed frame portion 1b is provided with a female screw hole 28 that can be screwed into the screw rod 23.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electronic balance, and more particularly, to an improved technology of a four-corner adjustment mechanism in an electromagnetic balance type electronic balance.

[0002]

[Prior art]

 The electromagnetic balance type electronic balance electrically detects a minute displacement of the electromagnetic balance portion caused by the load of the weighing object, applies an electromagnetic force so that this displacement becomes zero, and generates a current corresponding to the electromagnetic force applied at this time. The principle of measurement is to obtain the load of the object to be weighed by measuring, and since this kind of electronic balance has high measurement accuracy, it has recently been used in a wide range of fields.

FIG. 7 shows an example of this kind of electronic balance. The electronic balance shown in the figure has a frame 1 formed in a substantially rectangular parallelepiped shape, and a pair of upper and lower sub-bars 2 and 3 arranged in the vertical direction of the frame 1 so as to extend along one end of the frame 1. A front arm 4 is vertically installed to receive the load of the weighing object placed on the weighing pan 4. A plurality of plate panels 6 (also called elastic fulcrums) are interposed between the upper and lower sub-bars 2 and 3 and the frame 1 and between the upper and lower sub-bars 2 and 3. As a result, the Roberval mechanism 7 is configured.

On the other hand, an electromagnetic balance portion 8 is provided inside the frame 1 formed in a frame shape. The electromagnetic balance portion 8 is provided so as to cover the yoke 8a, the magnet 8b arranged in the yoke 8a, the pole piece 8c mounted on the magnet 8b, and the upper side of the pole piece 8c. It is composed of a coil 8d. The coil 8d is supported by a beam 9 arranged in parallel with the sub-bars 2, 3, one end of the beam 9 is connected to the frame 1 by a leaf spring 10, and the beam 9 is connected at this connection point. It swings up and down in the vertical plane with the fulcrum as the fulcrum. In the electronic balance configured as described above, when a weighing object is placed on the weighing pan 4, the load is transmitted to the Roberval mechanism 7 via the front arm 5 and further transmitted to one end of the beam 9 via the suspension band 11. To be done.

When the load is transmitted to one end of the beam 9, the beam 9 swings and moves by an amount corresponding to the load with the connection point between the leaf spring 10 and the frame 1 as a fulcrum. When the beam 9 swings in this manner, the coil 9d is supported by the beam 9, so that the electromagnetic force acting between the coil 8d and the pole piece 8c changes. When the change in the electromagnetic force is detected and a current that cancels the change in the electromagnetic force is supplied to the coil 8d, the positional relationship between the coil 8d and the pole piece 8c is maintained as it is.

In this type of electronic balance, the load to be weighed is indirectly measured by measuring the current supplied to the coil 8d at this time. However, in such a measurement mechanism, if the Roberval mechanism 7 is unbalanced, the measured values vary depending on whether the weighing object is placed in the center of the weighing dish 4 or on the periphery. Therefore, in this kind of balance, the four-corner adjustment mechanism 12 is provided in order to adjust such variations.

In the four-corner adjustment mechanism 12 shown in the figure, the upper sub-bar 2 is provided in the vicinity of the portion connected to the frame 1 via the leaf spring 6, and extends horizontally to the upper end side of the frame 1. The slit 1a is formed, and the fixed frame portion 1b and the movable frame portion 1c are provided on the upper side of the frame 1 so as to pass through the hole 1d formed in the movable frame portion 1c. The lower end side is composed of an adjusting screw 13 screwed to the fixed frame portion 1b.

In the four-corner adjusting mechanism 12 having such a configuration, the weighing objects having the same load are placed on the center and the periphery of the weighing dish 4, respectively, and the adjusting screw 13 is adjusted so that the measured values substantially match between them. The amount of screwing to the fixed frame portion 1b side is changed. However, the four-corner adjusting mechanism 12 having such a structure has the technical problems described below.

[0009]

[Problems to be solved by the device]

 That is, in the conventional four-corner adjustment mechanism 12 described above, the amount of screwing of the adjusting screw 13 to the fixed frame portion 1b side is changed to change the bending amount of the movable frame portion 1c to adjust the four corners. Since the adjustment depends only on the screw pitch of No. 13, there is a problem that it is difficult to perform highly accurate adjustment. Further, when the movable frame portion 1c is excessively bent downward during the adjustment, even if the adjusting screw 13 is moved up and down, the movable frame portion 1c does not always return to the upper portion, which is troublesome for the adjustment work. There was also a problem.

Further, even after the adjustment is completed, since the diameter of the adjusting screw 13 is relatively small, the frictional force (tightening force) on the peripheral surface thereof is small, and it is difficult to maintain the adjusted state. There is also a problem in that when an external force such as vibration or disturbance is applied to 1c, the displacement occurs. The present invention has been made in view of such conventional problems, and a first object thereof is to provide an electronic balance having a four-corner adjustment mechanism capable of highly accurate adjustment. A second object is to provide an electronic balance having a four-corner adjustment mechanism that can be easily adjusted and can maintain its state after adjustment.

[0011]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention arranges a pair of upper and lower auxiliary rods in a vertical direction of a frame, and applies a load of a weighing object placed on a weighing pan along one end side of the frame. A Roberval mechanism in which a front arm for receiving is hung, and a plurality of leaf springs are interposed between the sub-bar, the frame and the front arm, and measurement due to the placement position of the weighing object on the weighing dish. In an electronic balance having a four-corner adjustment mechanism that adjusts the variation of the value and transmitting the load of the weighing object to the electromagnetic balance section via this Roberval mechanism, the four-corner adjustment mechanism includes the upper sub-bar and the frame. A fixed frame portion provided on the upper side of the frame is formed by forming a slit extending in the horizontal direction on the upper end side of the frame, the slit being provided close to the mounting portion of the leaf spring interposed therebetween. Yes A frame part, a spring interposed between the fixed frame part and the movable frame part, a hollow adjustment bolt having a screw formed on the inner and outer circumferences screwed to the movable frame part, and a lower end side. It has a screw rod fixed to the fixed frame part and having an upper end side screwed to the inner circumference of the adjustment bolt, and the screw pitch of the adjustment bolt is different between the inner circumference and the outer circumference.

The screw pitch of the adjusting bolt can be set so that the outer peripheral side is larger than the inner peripheral side. Further, the screw rod can be fixed to the fixed frame portion by a set screw screwed to the end surface side of the fixed frame portion. Further, as a second invention, a pair of upper and lower auxiliary rods are arranged in the vertical direction of the frame, and the front arm receives the load of the weighing object placed on the weighing dish along one end side of the frame. And a measurement by the position of the weighing object placed on the weighing pan, and the Roberval mechanism in which a plurality of leaf springs are interposed between the sub-bar, the frame and the front arm. In an electronic balance having a four-corner adjustment mechanism for adjusting the variation of the value and transmitting the load of the weighing object to the electromagnetic balance section via this Roberval mechanism, the four-corner adjustment mechanism includes the upper sub-bar and the frame. A fixed frame portion provided on the upper side of the frame is provided in the vicinity of the mounting portion of the leaf spring interposed between the fixed frame portion and a slit extending horizontally in the upper end side of the frame. Movable frame Section, a spring interposed between the fixed frame section and the movable frame section, a hollow adjustment bolt screwed to the movable frame section and having a thread engraved on the inner and outer circumferences thereof, and the lower end side thereof is There is a screw rod that is screwed to the fixed frame part so that it cannot move downward, and the upper end side is screwed to the inner circumference of the adjustment bolt, and the screw pitch of the adjustment bolt is different on the inner and outer circumferences. Characterize.

[0013]

[Action]

 According to the electronic balance having the above configuration, the four-corner adjustment mechanism is provided in the vicinity of the mounting portion of the leaf spring interposed between the upper sub-bar and the frame, and the slit extending horizontally in the upper end side of the frame. A fixed frame part and a movable frame part provided on the upper side of the frame, a spring interposed between the fixed frame part and the movable frame part, and an inner and outer circumference screwed to the movable frame part. A hollow adjustment bolt having a screw engraved on it, a lower end side fixed to the fixed frame portion or screwed so as not to move downward, and an upper end side screwed to the inner circumference of the adjustment bolt. Since the screw pitch of the adjustment bolt is different on the inner and outer circumferences, rotating the adjustment bolt in the screwing direction lowers the movable frame part while compressing the spring by the amount corresponding to the difference in the screw pitch of the inner and outer circumferences. Swing Can.

Further, when the adjusting bolt is rotated in the loosening direction, the elastic force of the spring allows the movable frame portion to swing upward by an amount corresponding to the difference in the screw pitch between the inner and outer circumferences. Further, since the adjusting bolt is provided with screws on the inner and outer circumferences and has a relatively large diameter, the frictional force on the peripheral surface becomes large and the adjusting bolt can be securely fixed.

[0015]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same or corresponding portions as the above-mentioned conventional example. The electronic balance according to the present invention, like the conventional example shown in FIG. 7, has a frame 1 formed in a substantially rectangular parallelepiped shape, and a pair of upper and lower sub-bars 2 and 3 arranged in the vertical direction of the frame 1. Then, a front arm 4 is vertically provided along the one end of the frame 1 so as to receive the load of the weighing object placed on the weighing dish 4. Then, a plurality of leaf springs 6 (also referred to as elastic fulcrums) are interposed between the upper and lower sub-bars 2 and 3 and the frame 1 and between the upper and lower sub-bars 2 and 3 to provide a robber mechanism. 7 are configured.

On the other hand, an electromagnetic balance section 8 is provided inside the frame 1 formed in a frame shape. The electromagnetic balance portion 8 is provided so as to cover the yoke 8a, the magnet 8b arranged in the yoke 8a, the pole piece 8c mounted on the magnet 8b, and the upper side of the pole piece 8c. It is composed of a coil 8d. The coil 8d is supported by a beam 9 arranged in parallel with the sub-bars 2, 3, one end of the beam 9 is connected to the frame 1 by a leaf spring 10, and the beam 9 is connected at this connection point. It swings up and down in the vertical plane with the fulcrum as the fulcrum. In the electronic balance configured as described above, when a weighing object is placed on the weighing pan 4, the load is transmitted to the Roberval mechanism 7 via the front arm 5 and further transmitted to one end of the beam 9 via the suspension band 11. To be done.

When the load is transmitted to one end of the beam 9, the beam 9 swings by an amount corresponding to the load with the connection point between the leaf spring 10 and the frame 1 as a fulcrum. When the beam 9 swings in this way, the coil 9d is supported by the beam 9, so that the electromagnetic force acting between the coil 8d and the pole piece 8c changes. When the change in the electromagnetic force is detected and a current that cancels the change in the electromagnetic force is supplied to the coil 8d, the positional relationship between the coil 8d and the pole piece 8c is maintained as it is.

Then, the load of the weighing object is indirectly measured by measuring the current supplied to the coil 8d at this time, and the basic configuration of the electronic balance for the load measurement is the conventional one. The balance is similar to this type of balance, but in particular, the four-corner adjusting mechanism has the salient features described below. That is, FIGS. 1 and 2 show a first embodiment of the four-corner adjusting mechanism 20 employed in the electronic balance of the present invention. The four-corner adjusting mechanism 20 shown in the figure has a spring 21, an adjusting bolt 22, and a screw rod 23. The leaf spring 6 is mounted between the upper sub-bar 2 and the frame 1. It is provided close to the section.

In addition, as in each of the embodiments described below, in an ordinary electromagnetic balance type balance, the sub-bars 2 and 3 are formed in a substantially U-shaped plane, and the leaf spring 6 is attached. The parts are provided at two locations with the same configuration in the direction orthogonal to the paper surface of FIGS. 1 and 2, and a pair of four-corner adjustment mechanisms 20 with the same configuration are provided correspondingly. Then, one of them is omitted.

The frame 1 is provided with a slit 1 a extending horizontally in the upper end thereof, a fixed frame portion 1 b on the upper side of the frame 1, and a movable frame portion 1 c that bends in the vertical direction. . The spring 21 has a spiral shape and is interposed between the fixed frame portion 1b and the movable frame portion 1c such that the upper and lower ends thereof are in contact with each other. The adjusting bolt 22 is formed in a hollow shape and has an external thread 24 engraved on its outer circumference and an internal thread 25 engraved on the inner circumference. The thread pitch of these screws 24, 25 is the outer circumference side. The male screw 24 is larger than the female screw 25 on the inner peripheral side, and the female screw 25 is formed so as to be screwable with the screw rod 23 having the male screw engraved over its entire length. The screw pitch of the adjusting bolt 22 may be set so that the male screw 24 on the outer peripheral side is smaller than the female screw 25 on the inner peripheral side.

The movable frame portion 1 c is provided with a female screw hole 27 penetrating in the thickness direction, and the female screw hole 27 is formed so as to be screwed with the male screw 24 of the adjusting bolt 22. On the other hand, the fixed frame portion 1b is provided with a female screw hole 28 having a smaller diameter than the female screw hole 27 so as to correspond to the female screw hole 27, and the female screw hole 28 can be screwed with the screw rod 23. Has been formed. The female screw hole 28 has a tip extending to the vicinity of the lower surface of the frame 1, and a screw hole 29 for screwing a set screw that opens to the side surface of the frame 1 is provided in the vicinity of the tip. The screw 30 is screwed.

In the four-corner adjustment mechanism 20 configured as described above, first, the spring 21 is interposed between the fixed and movable frame portions 1b and 1c such that the spring 21 is aligned with the centers of the female screw holes 27 and 28, In this state, the screw rod 23 is screwed into the female screw hole 28, and the set screw 30 is screwed and fixed in the screw hole 29. The male screw 24 and the female screw 25 are screwed into the female screw hole 27 and the screw rod 23. The adjustment bolt 22 is attached while wearing.

When the balance of the Roberval mechanism 7 is adjusted, the weighing objects having the same load are placed on the center and the periphery of the weighing dish 4 so that the measured values are substantially the same. The screwing amount of the adjusting bolt 23 is changed. In this case, the thread pitch of the adjusting bolt 23 is different between the male screw 24 and the female screw 25, and the male screw 24 is larger than the female screw 25.

Therefore, when the adjusting bolt 23 is rotated in the screwing direction, the movable frame portion 1c swings downward while compressing the spring 21 by an amount corresponding to the difference between the screw pitches of the inner and outer circumferences. A very small amount of movement can be selected, enabling highly accurate adjustment. When the adjusting bolt 23 is rotated in the loosening direction, the elastic force of the spring 21 causes the movable frame portion 1c to swivel upward rapidly by an amount corresponding to the difference in screw pitch between the male screw 24 and the female screw 2. The adjustment work becomes very easy. Further, since the adjusting bolt 23 has screws 24 and 25 on the inner and outer circumferences and has a relatively large diameter, the frictional force on the peripheral surface becomes large and there is no fear of loosening after adjustment, and the adjusting state is maintained. be able to.

3 and 4 show a second embodiment of the present invention, and only the characteristic points will be described below. The four-corner adjusting mechanism 20a shown in the figure has the same structure as the spring 21, the adjusting bolt 22 and the like in the above-described embodiment, but is characterized by the structure of the screw rod 23a. It is provided only on the upper end side and not on the lower end side.

On the other hand, a hole 28a is provided on the fixed frame 1b side instead of the female screw hole 28. The set screw 30a has a sharp tip. With the four-corner adjusting mechanism 20a configured as described above, the same operational effects as those of the first embodiment can be obtained. 5 and 6 show a third embodiment of the present invention, and only the characteristic points will be described below. The four-corner adjusting mechanism 20b shown in the same figure replaces the screw hole 29 of the first embodiment with which the set screw is screwed, and extends the hole 29b to the inner side of the lower end of the female screw hole 28. Instead of this, a pin 31 is inserted, and the lower end of the screw rod 23 screwed to the female screw 28 abuts on this pin 31 so that its downward movement is disabled.

With the four-corner adjusting mechanism 20b thus configured, the same operational effect as that of the above-described embodiment can be obtained. In addition, in the above-mentioned embodiment, the balance using the sub-bars 2 and 3 and the leaf spring 6 separated is illustrated as the member constituting the Roberval mechanism 7, but the implementation of the present invention is not limited thereto. However, the present invention can also be applied to, for example, a balance using a Roberval mechanism in which a sub-bar and a leaf spring are integrally formed.

[0028]

[Effect of device]

 As described above in detail in the embodiments, according to the electronic balance according to the present invention, the four corners can be adjusted with high accuracy, the adjustment work is easy, and the state is maintained even after the adjustment. It will be possible.

[Submission date] August 17, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

Further, even if the adjustment is completed, if the diameter of the adjusting screw 13 is relatively small, the frictional force on the peripheral surface of the adjusting screw 13 is small, and it is difficult to maintain the adjusted state. For example, the movable frame portion 1c vibrates. When or disturbance external force due to such Ru Kuwawa, there is a problem that the positional shift occurs. The present invention has been made in view of such conventional problems, and a first object thereof is to provide an electronic balance having a four-corner adjustment mechanism capable of highly accurate adjustment. A second object is to provide an electronic balance having a four-corner adjustment mechanism that can be easily adjusted and can maintain its state after adjustment.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

[0013]

[Action]

According to the electronic balance having the above configuration, the four-corner adjustment mechanism is provided in the vicinity of the mounting portion of the leaf spring interposed between the upper sub-bar and the frame, and the slit extending horizontally in the upper end side of the frame. A fixed frame part and a movable frame part provided on the upper side of the frame, a spring interposed between the fixed frame part and the movable frame part, and an inner and outer circumference screwed to the movable frame part. A hollow adjustment bolt having a screw engraved in it, a lower end side that is fixed to the fixed frame portion or is screwed so as not to move downward, and an upper end side has a screw rod that is screwed into the inner circumference of the adjustment bolt. Since the screw pitch of the adjustment bolt is different on the inner and outer circumferences, rotating the adjustment bolt in a certain direction lowers the movable frame part while compressing the spring by the amount corresponding to the difference in the inner and outer thread pitches. , Oh Rui is fine upward It can be.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

Further, when the adjusting bolt is rotated in the opposite direction, the elastic force of the spring can finely move the movable frame portion upward or downward by an amount corresponding to the difference in the inner and outer peripheral pitches. it can. Further, since the adjusting bolt is provided with screws on the inner and outer circumferences and has a comparatively large diameter, the frictional force on the peripheral surface becomes large and the adjusting bolt can be securely fixed.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

When the balance of the Roberval mechanism 7 is adjusted, the weighing objects having the same load are placed on the center and the periphery of the weighing dish 4 so that the measured values are substantially the same. changing the screwing amount of the adjusting bolt 2 2. In this case, the screw pitch of the adjustment bolt 2 2 is different in the external thread 24 and the female screw 25, towards the external thread 24 is larger than the internal thread 25.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction content]

[0024] Thus, by rotating in a direction screwing the adjusting bolt 2 2, the amount corresponding to the difference between the thread pitch of the inner and outer circumference, the movable frame portion 1c is swung downward while compressing the spring 21, from the thread pitch Even with a very small amount of movement, it is possible to make highly accurate adjustments. Also, it is rotated in the direction of loosening the adjustment bolt 2 2, by the elastic force of the spring 21, by the amount corresponding to the difference between the thread pitch of the external thread 24 and the internal thread 2, rapidly rocking the movable frame part 1 c upward It can be moved and the adjustment work becomes very easy. Further, adjustment bolt 2 2 have screw 24, 25 provided on the inner periphery, relatively since a large diameter ones, skin friction increases, there is no fear that loosening after the adjustment, maintain the adjusted state can do.

[Brief description of drawings]

FIG. 1 is an exploded view of essential parts showing a first embodiment of an electronic balance according to the present invention.

FIG. 2 is a cross-sectional view of a main part of the assembled state of FIG.

FIG. 3 is an exploded view of essential parts showing a second embodiment of the electronic balance according to the present invention.

FIG. 4 is a cross-sectional view of essential parts in the assembled state of FIG.

FIG. 5 is an exploded view of essential parts showing a third embodiment of the electronic balance according to the present invention.

6 is a cross-sectional view of a main part of the assembled state of FIG.

FIG. 7 is a side view of an electronic balance that employs a conventional four-corner adjustment mechanism.

[Explanation of symbols]

 20, 20a, 20b Four-corner adjustment mechanism 21 Spring 22 Adjustment bolt 23, 23a Screw rod 24 Male screw 25 Female screw

Claims (4)

[Scope of utility model registration request] 1. A front arm, which is provided with a pair of upper and lower sub-bars arranged in a vertical direction of a frame and which extends along one end of the frame and which receives a load of a weighing object placed on a weighing dish. Then, a Roverval mechanism having a plurality of leaf springs interposed between the sub-bar, the frame, and the front arm, and a variation in measured values due to the placement position of the weighing object on the weighing dish are adjusted. In an electronic balance having a four-corner adjustment mechanism and transmitting the load of the weighing object to the electromagnetic balance section via the Roberval mechanism, the four-corner adjustment mechanism is interposed between the upper sub-bar and the frame. A fixed frame part and a movable frame part provided on an upper side of the frame, the slit being provided in the vicinity of the mounting part of the leaf spring, the slit extending horizontally in the upper end side of the frame; A spring interposed between the ram section and the movable frame section, a hollow adjustment bolt having an inner and outer circumference screwed into the movable frame section, and a lower end fixed to the fixed frame section. The electronic balance has a screw rod whose upper end is screwed to the inner circumference of the adjustment bolt, and the screw pitch of the adjustment bolt is different between the inner circumference and the outer circumference. 2. The electronic balance according to claim 1, wherein the screw pitch is set larger on the outer peripheral side than on the inner peripheral side. 3. The electronic balance according to claim 1, wherein the screw rod is fixed to the fixed frame portion by a set screw screwed to an end surface side of the fixed frame portion. 4. A pair of upper and lower sub-bars are arranged in the vertical direction of the frame, and a front arm is vertically provided so as to extend along one end of the frame and receive a load of a weighing object placed on a weighing pan. Then, a Roverval mechanism having a plurality of leaf springs interposed between the sub-bar, the frame, and the front arm, and a variation in measured values due to the placement position of the weighing object on the weighing dish are adjusted. An electronic balance comprising a four-corner adjustment mechanism and transmitting a load of the weighing object to an electromagnetic balance section via the Roberval mechanism, wherein the four-corner adjustment mechanism is interposed between the upper sub-bar and the frame. A fixed frame part and a movable frame part provided on an upper side of the frame, the slit being provided in the vicinity of the mounting part of the leaf spring, the slit extending horizontally in the upper end side of the frame; A spring interposed between the ram section and the movable frame section, a hollow adjustment bolt screwed on the movable frame section and having an inner and outer circumference with a thread engraved therein, and a lower end side of which is lower than the fixed frame section. An electronic balance having a threaded rod screwed immovably and having an upper end screwed to the inner circumference of the adjustment bolt, wherein the thread pitch of the adjustment bolt is different between the inner circumference and the outer circumference.