JPH0220647Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a spring-loaded top-pan type indicating scale having a parallel link mechanism.

[Conventional technology]

In the above-mentioned conventional scale, a pan support plate 3 provided on the lower surface of a pan 1 is connected to the free ends of upper and lower plate-shaped parallel links 4 and 5 having fulcrums 9 and 10 on a parallel link support 6 fixed to a scale body 26. Spring hangings 11a, 1 supported by rods 7, 8 and provided on the left and right at the bottom of the tray receiving plate 3
1b and spring hangers 13, 15 provided on the upper part of the main body, two springs 12a, 12b are attached together with a rack 22 (described later) on a vertical plane passing through the plane center O of the plate 1 as shown by the chain lines 12a, 12b in FIG. The rack 22 is connected by a pin 21 to a rack lever 20 provided integrally with the lower link 5. The rack 22 is engaged with a pinion 23 fixed to a pointer shaft 23a horizontally suspended between the front and rear of the main body, and the scale of a scale plate 25 is read by a pointer 24 fixed to the pointer shaft 23a.

When a load is applied to the plate 1, the plate receiving plate 3 and the lower spring suspensions 11a, 11b descend while stretching the springs 12a, 12b, and the lever 2 adjusts the inclination of the parallel links 4, 5 according to the amount of deflection of the springs at that time.
0, and the pinion 23 and pointer 24 are rotated by the amount of movement of the rack 22 connected thereto to indicate the scale.

Therefore, depending on the load, the springs 12a, 12b, parallel links 4, 5, rack lever 20, rack 22,
If the pinions 23 move in proportion to each other, scale accuracy is obtained.

However, the equal division ratio of the arcuate motion angles around the fulcrums 9 and 10 of the parallel links 4 and 5 and the equal division ratio of the linear motion distances of the connecting points 7 and 8 between the plate support plate 3 and the parallel links 4 and 5 are as follows. They do not match, and the latter is the sin of the angle of motion
It is proportional to . The rack lever 20 also moves in the same arc as the lower parallel link 5, and the equal division ratio of its movement angle and the connection point 2 with the rack 22 are
Similarly, the equal division ratio of the linear motion distance of 1 does not match. Also, due to the arc movement of the parallel links 4 and 5, the plate 1, plate receiving plate 3, and spring suspensions 11a and 11b move horizontally to the lower right by a distance e while maintaining their vertical positions. , which causes a difference in force when stretching while tilting.

The above three points are the cause of the scale error, and the equal division ratio between the arc motion angle and the linear motion distance is
This is designed to be proportional to the scale division ratio by the pinion 23. The scale division ratio is, for example, 1/500 when the weight of the scale plate per revolution is 10 kg and one scale is 20 g.

[The problem that the idea attempts to solve]

The above error factor is almost attributable to the arc movement angle θ, and it is clear from the above sin function that the smaller the angle θ, the better the division ratio (accuracy) corresponding to the scale division ratio. Therefore, easy 2
If the linear momentum of the lever 2 is constant, it is effective to lengthen the lever 20 so as to reduce the angle θ.

However, conventionally, as mentioned above, two springs 12
a, 12b are placed on the left and right on a vertical plane passing through the center of the plane of the plate 1, together with the rack lever 20 and the rack 22, so the length of the rack lever 20 is restricted by the spring 12b on the right side and cannot be made longer. .

Therefore, an object of the present invention is to eliminate the above-mentioned restrictions and increase the length of the latch lever 20.

[Means and actions to solve the problem]

The present invention is a spring-type upper pan-type indicating scale having parallel link mechanisms 4 and 5, in which two springs 12a and 12b that receive the load from the pan support plate 3 are arranged horizontally and diagonally with respect to the center O of the pan plane. By arranging the rack lever 20 symmetrically in the direction, it is possible to lengthen the rack lever 20 without being restricted by the spring 12b, and the accuracy of the scale can be improved by reducing the arcuate movement angle θ of the rack lever 20. can.

〔Example〕

A load receiving part is constituted by a pair of front and rear rods 2 provided on the lower surface of the plate 1, L-shaped fittings 2a fixed to each rod, and a U-shaped planar plate receiving plate 3 whose upper end is fixed between the front and rear fittings 2a. .

The upper hanging hook 18a of the left spring 12a is attached to the main body 2.
It is hung on a spring hanger 13 attached to a plate-like member 13a fixed between the front and rear of the frame 6. The upper hanging hook 18a of the right spring 12b is hung on the adjustment link 15. However, the adjustment link 15 is composed of a plate member 15a having a U-shaped side surface fixed thereto, and this plate member 15a is supported by the fulcrum shaft 14 at the front and rear of the main body 26.
A tension rod receiver 17 is attached to the zero adjustment link member 15a by the shaft 16 on the side opposite to the spring suspension side with respect to the shaft 14, and the upper threaded portion of the adjustment rod 28 inserted into the bracket 29 fixed to the lower part of the main body 26 is attached. It is screwed into the above-mentioned tension rod receiver 17, and the zero point is adjusted by operating the tension ball 19. Reference numeral 27 indicates a cover, and 3a in FIG. 2 indicates through holes for the rack lever 20 and the rack 22 provided in the U-shaped tray receiving plate 3.

[Effect of idea]

FIG. 5 is a diagram illustrating the effect of the present invention. If the linear momentum of the rack 22 from zero point 0 to the weight W is constant, the present invention is as shown by the solid line, as opposed to the conventional example shown by the two-dot chain line. In addition, the arcuate movement angle of the rack lever and parallel link is reduced, the three error factors mentioned above are improved, and the accuracy of the scale is improved. Although the rack 22 is inclined with respect to the center of the pinion 23 than before, it does not affect the scale reading.

Furthermore, since the arcuate movement angle of the latch lever is small, it is effective in making the entire structure more compact. Note that in order to lengthen the lever of the conventional type, the spring must be placed outward, resulting in a larger overall size.

[Brief explanation of drawings]

Fig. 1 is a front view of the main parts of an indicating scale in which the present invention is implemented, Fig. 2 is a plan view thereof, Fig. 3 is a partial front view, Fig. 4 is a partial side view, and Fig. 5 is a partial front view. Diagram explaining the movement of the rack lever rack. 3 is a plate receiving plate, 4 and 5 are parallel links, 12a, 1
2b is a spring, 20 is a rack lever, 22 is a rack, and 23 is a pinion.

Claims (1)

[Scope of utility model registration request] In a spring-type upper pan-type indicator scale with a parallel link mechanism, the latch lever can be adjusted by arranging the two springs that receive the load from the pan support plate symmetrically on the left and right and in the diagonal direction with respect to the center of the pan plane. A spring type top plate type indicating scale having a parallel link mechanism in which a rack is arranged without being constrained by a spring, and a rack connected to the rack lever is engaged with a pinion on a pointer shaft at an angle.