JPH0329718Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a top-pan type balance having a Roberval mechanism.

<Problems to be solved by the invention> Conventional top-pan type balances have no protection against unexpected forces applied to the pan, and are especially vulnerable to horizontal forces as indicated by F in Figure 1. It was hot.

Therefore, an object of the present invention is to provide a balance equipped with a device that protects the roberval mechanism from unexpected external forces without impairing measurement accuracy or measurement sensitivity.

<Means for solving the problem> The present invention forms the lower end surface of the support rod of the balance pan into a flat surface of a predetermined shape, for example, a cylindrical shape, and attaches a ring to the horizontally movable member of the Roberval mechanism at a position where it comes into contact with the lower end of the support rod. The lower end of the support rod is fitted with a ring-shaped projection in contact with the lower end of the support rod, and the portion where the ring-shaped projection is provided is connected to the lower part of the support rod by a tension spring. It is said that

<Operation> When a vertical load is applied to the balance pan, that load is directly transmitted to the Roberval mechanism via the contact surface of the lower end of the support rod.

If an unexpected force is applied to the balance pan,
The horizontal component of the force causes a part of the contact surface to separate and tilt the support rod and balance pan, so that most of the unexpected force does not act on the Roberbal mechanism, and the Roberbal mechanism is protected from external forces. When the external force is removed, the normal contact state is restored by the force of the tension spring.

<Example> The drawings show cross-sectional views of embodiments of the present invention.

The balance pan 1 is supported by a vertical support rod 2,
A cylindrical portion 3 is formed at the lower part of the support rod 2, and the lower end surface is open. On the other hand, the Roberval mechanism includes a movable member 4, an upper horizontal member 5, a lower horizontal member 6, an elastic body 7 that connects the movable ends of both horizontal members and the movable member,
8. Consists of elastic bodies 9 and 10 that connect the fixed ends of both horizontal members and the fixed member. A protruding portion 11 is attached to the side of the movable member 4 of this Roberval mechanism, and a ring-shaped protrusion 12 is integrally formed on the upper surface of the distal end portion of the protruding portion 11. The inner surface of this ring-shaped projection 12 is formed into a tapered shape with a widening tip, and the outer diameter of the cylindrical portion 3 fits into the inner surface. A tension spring 13 is built in the cylindrical part 3, and its upper end is connected to the cylindrical part 3.
In addition, its lower end is hung on a pin 14 screwed to the corrugated portion 11. The height of the pin 14 can be adjusted with a screw.

In such a device, when a vertical load is applied to the balance pan 1, the load is directly transmitted to the Roberval mechanism via the support rod 2. If, for example, a horizontal force as shown by F in FIG. 1 is applied, the balance pan 1 and its support rod 2 will be rotated to the right around point A, and that force will not be transmitted to the Roberval mechanism. The displacement stops when the balance pan 1 hits the case 15 of the balance. When the horizontal force F is removed, the restoring force of the tension spring 13 returns the entire lower end surface of the cylindrical portion 3 to the normal state in which it contacts the ring-shaped protrusion 12. By adjusting the height of the pin 14, the restoring force of the tension spring 13 can be adjusted.

The ring-shaped protrusion of the present invention has an outer surface formed in a tapered shape with a tapered tip, and a cylindrical portion 3 on the outer surface.
The inner diameter of the inner diameter may be fitted. Furthermore, the ring-shaped protrusion can be formed in a circular, rectangular, or other arbitrary shape, and either the lower end of the cylinder or the ring-shaped protrusion may be formed intermittently.

<Effects> According to the present invention, even if an unexpected horizontal force acts on the balance pan, the roberval mechanism will not be damaged. Furthermore, even when the load on the balance pan is biased from the axis of the support rod, no undue force is applied to the roberval mechanism, improving the durability and reliability of the balance.

[Brief explanation of drawings]

The drawing is a sectional view showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Balance pan, 2... Support rod, 3... Cylindrical part, 4... Movable member of Roberval mechanism, 11...
Protrusion portion, 12... ring-shaped protrusion, 13... tension spring.

Claims (1)

[Claims for Utility Model Registration] (1) In a balance having a Roberval mechanism, the lower end surface of the support rod of the balance pan is formed into a flat surface of a predetermined shape and size, and comes into contact with the lower end of the support rod of the protruding portion of the Roberval mechanism. A balance characterized in that a ring-shaped protrusion that fits into the predetermined shape and dimensions is provided at a position, and the portion where the ring-shaped protrusion is provided is connected to the support rod by a tension spring. (2) Claim 1 of the utility model registration claim, wherein the inner surface of the ring-shaped protrusion has a tapered shape that expands upward, and the lower end surface of the support rod has an outer diameter that fits into the inner surface of the taper. balance. (3) The balance according to claim 1, wherein the tension of the tension spring is adjustable.