JPH0723241U - Balance - Google Patents

Abstract

(57) [Abstract] [Purpose] Preventing mechanical parts from being damaged by strong impacts during transportation, etc., and absorbing weak impacts during normal measurement to prevent performance defects. Provide a balance. A first limiting member and a second limiting member for limiting a displacement width of a movable portion are provided, and a fragile portion even when a strong impact is applied by the first limiting member having a wide displaceable width of the movable portion. The second limiting member so that the movable portion has a narrower displaceable width than the first limiting member, and the collision mitigating member is provided when the movable portion collides with the second limiting member. Try to hit gently through.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to balances.

[0002]

[Prior art]

 In a balance, generally, a load placed on a weighing pan is transmitted to a load sensor such as a balanced electromagnetic force generator or a load cell via a load transmission shaft or a lever, and the magnitude of the load is measured. Since the load sensor and load transmission mechanism are vulnerable to impact, they usually need protection.

Conventionally, for the purpose of such protection, a stopper mechanism (restricting member) has been provided so that a movable part which is displaced when a load is changed cannot be displaced beyond a certain range.

FIG. 3 shows a cross-sectional view of an electronic balance having a conventional movable part protection mechanism. In this balance, the load placed on the weighing pan 1 is transmitted to the movable column 3 via the load transmission shaft 2. The movable column 3 is connected and supported to the fixed portion 4 by the two parallel links 5a and 5b and the elastic member 11 to form a parallel movement mechanism. The movable column 3 is connected to the lever 7 via a link 6. An electromagnetic force generator 9 is connected to the other end of the lever 7 with a fulcrum 8 in between. Then, the electromagnetic force generator 9 generates an electromagnetic force so as to balance with the load transmitted from the weighing pan, and the magnitude of the load is detected from the current value at that time.

In this balance, a stopper 10 is provided on the fixed portion 4 in order to protect the movable portion. That is, the stopper 10 is provided at a portion of the fixed portion 4 facing one end of the lever 7 so that the end portion of the lever 7 is sandwiched with a predetermined gap. As a result, the displaceable width of the lever 7 is limited within this gap, so that even if there is an impact, the movable part does not shake significantly and the fragile part is prevented from being damaged. There is.

[0006]

[Problems to be solved by the device]

 The stoppers found in the above-mentioned prior arts are mainly intended to protect against a strong shock received during transportation. However, in this stopper 10, when the lever 7 collides with the stopper 10 due to a strong impact, the link 6, the fulcrum 8, the electromagnetic force generator 9 and the elastic member 11 are certainly not damaged. Since it is necessary to use a member with high rigidity for such a stopper, it is not possible to absorb the impact when the lever collides with the stopper.Especially for highly sensitive balances, the impact may adversely affect the performance even temporarily. I was giving.

Further, when a load larger than a predetermined amount is applied on the weighing pan, the movable part is displaced and the lever 7 hits the stopper 10, but the impact at the moment of hitting the link 6, the fulcrum 8 and the elastic member 11 is adversely affected. And sometimes it became impossible to measure accurately.

The present invention has been made in view of the above problems, and prevents damage to mechanical parts from a large impact caused by transportation of a balance or a fall of an object on a weighing pan, and displacement of a movable part. The purpose is to prevent performance defects due to impact when hitting the stopper.

[0009]

[Means for Solving the Problems]

 The present invention adopts the following configuration in order to achieve such an object. That is, the balance according to the present invention is a balance that measures the load by transmitting the load to the load sensor via the lever engaged with the movable part on the balance plate to which the load is transmitted. Alternatively, a first limiting member for limiting the displacement width of the lever and a second limiting member for limiting the displacement width of the movable portion narrower than the first limiting member are provided, and the second limiting member is movable. It is characterized in that it is provided with a shock absorbing member when the section or lever collides with the limiting member.

The operation of the balance having this structure will be described below.

[0011]

[Action]

 In the balance having the configuration of the present invention, there are a first limiting member and a second limiting member that limit the displacement width of the movable portion. Of these, in the first limiting member, the movable width of the movable portion is limited to such an extent that the link, the fulcrum, the elastic member, and the electromagnetic force generator are not damaged. Therefore, even if there is a strong impact, the displacement does not occur to the extent that the movable part collides with the limiting member, and thus the damage can be prevented.

Further, the second restricting member has a narrower movable width of the movable part than the first restricting member, and moreover, when the movable part collides with the restricting member, it is gently hit by the collision mitigating member. , The shock is alleviated. Therefore, even if there is a weak impact that may occur during normal measurement, absorbing this impact with the relaxation member can prevent the performance from being adversely affected.

[0013]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a balance showing an embodiment of the present invention, and FIG. 2 is an enlarged view of a main part thereof. The same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, the elastic body 23 is attached to the end portion of the lever 7. Above and below the end of the lever 7 and the elastic body 23, stoppers 20 (restricting members) protruding from the fixing portion 4 are provided. The stopper 20 comprises a first stopper 21 (first limiting member) facing the lever 7 and a second stopper 22 (second limiting member) facing the elastic body 23. Has a wider gap than the second stopper. That is, the displacement width a until the end of the lever 7 hits the first stopper 22 is larger than the displacement width b until the elastic body 23 hits the second stopper 22.

Next, the operation of this balance will be described. When a load is placed on the weighing pan 1, the load transmission shaft 2, the movable column 3, and the movable portion of the lever 7 are displaced with respect to the fixed portion 4. That is, the movable column 3 supported by the fixed portion 4 via the parallel links 5 a and 5 b and the elastic member 11 moves downward due to the load of the weighing pan 1, and is attached to the movable column 3 via the link 6. The linked lever 7 moves downward on the link 6 side, and moves upward on the other end side having the electromagnetic force generator 9 sandwiching the fulcrum 8. The electromagnetic force required to restore this displacement is generated by the electromagnetic force generator 9 provided on the lever 7, and the magnitude of the load is measured from the value of the current passed to obtain the electromagnetic force.

When an object having a large load is placed on the weighing pan, the movable part tends to be largely displaced at that moment. However, when the displacement width becomes the width b between the elastic body 23 and the second stopper 22, the elastic body 23 contacts the second stopper 22. At this time, the impact of the elastic body 23 on the lever 7 is alleviated and the end portion of the lever 7 does not hit the first stopper 21, so that the link 6, the fulcrum 8, the elastic member 11, the electromagnetic force generator 9, and the like are not generated. It does not impact any fragile area. Therefore, such impact does not cause performance defects such as loss of measurement reproducibility.

On the other hand, if there is a large shock during transportation of the device, or if a heavy object is accidentally dropped during measurement and a strong shock is given, the elastic body 23 contacts the second stopper 22 and absorbs it. Greater impact than possible is transmitted. In this case, the contact between the elastic body 23 and the second stopper 22 plays almost no role, but instead, the lever 7 collides with the first stopper 21, so that the link 6, the fulcrum 8 and the elastic member 11 are contacted. It is possible to protect fragile parts such as the electromagnetic force generator 9 and the electromagnetic force generator 9 from being damaged. Therefore, when a strong shock is applied, accurate measurement cannot be temporarily performed in terms of reproducibility, but the device can be prevented from being broken.

Although the first stopper 21 and the second stopper 22 are integrally formed in this embodiment, the present invention is not limited to this, and as shown in FIG. 4, the first stopper 21 and the second stopper 21 may be formed. 22 and 22 may be provided in different places. Further, as shown in FIG. 5, the elastic body 23 may be provided on the fixed portion side 23.

In addition, an electromagnetic force balance type balance or the like may use an optical position sensor to detect the equilibrium position. However, an optical position sensor has a shutter for the position sensor. Can also be shared. FIG. 6 shows an example in which the second stopper 22 and the position sensor shutter are shared. In this example, a cutout portion serving as a position sensor shutter is provided at the end of the lever 7, a light receiving element is attached to the back side of the cutout portion, and a light emitting element is attached to the front side of the cutout portion. When in the equilibrium position, the light from the light emitting element passes through the cutout portion and is illuminated by the light receiving element to determine whether or not it is in equilibrium. By disposing the elastic body 23 attached to the fixed portion 4 in the cutout portion, the cutout portion of the position sensor shutter is shared as the second stopper.

Further, in the above example, the first stopper 21 and the second stopper 22 are provided on the electromagnetic force generator 9 of the lever 7, but the invention is not limited to this, and for example, the movable column 3 and the load transmission shaft 2 may be provided. You may provide the same 1st stopper and 2nd stopper.

[0021]

[Effect of device]

 According to the balance of the present invention, there are a first limiting member and a second limiting member that limit the displacement width of the movable part, and the movable range of the movable part is linked or fulcrum by the first limiting member. By limiting the elastic members and the electromagnetic force generator to the extent that they are not damaged, even if there is a strong impact, the movable part will not collide with this limiting member and will not be displaced enough to be damaged. Therefore, damage can be prevented. In addition, the second restricting member has a narrower movable width than the first restricting member, and when the movable part collides with the second restricting member, it is gently hit by the collision mitigating member. , The shock is alleviated. Therefore, even if there is a weak impact that may occur during normal measurement, absorbing this impact with the mitigating member can prevent adverse effects on performance such as poor reproducibility.

[Brief description of drawings]

FIG. 1 is a sectional view of a balance which is an embodiment of the present invention.

FIG. 2 is an enlarged view of a stopper portion which is a main part of FIG.

[Fig. 3] Cross-sectional view of a conventional balance

FIG. 4 is a view of a stopper portion of a balance which is another embodiment of the present invention.

FIG. 5 is a view of a stopper portion of a balance which is another embodiment of the present invention.

FIG. 6 is a view of a stopper portion of a balance which is another embodiment of the present invention.

[Explanation of symbols]

 1: Scale plate 3: Movable column 4: Fixed part 5a, 5b: Parallel link 6: Link 7: Lever 8: Support point 9: Electromagnetic force generator 11: Elastic member 20: Stopper 21: First stopper 22: Second stopper 23: Elastic body

Claims (1)

[Scope of utility model registration request] 1. A balance for measuring a load by transmitting the load to a load sensor via a lever engaged with a movable part to which the load on the balance plate is transmitted, the displacement range of the movable part or the lever. And a second limiting member that limits the displacement width of the movable portion narrower than that of the first limiting member. The second limiting member includes a movable portion or a lever. A balance having a shock absorbing member when it collides with a balance.