JPH0241388Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention has a so-called excessive input protection mechanism, which is suitable for use in sector scale indicators, for example, and has a function to prevent damage to the link mechanism in the event of excessive input. It's about links.

(Prior Art) FIG. 3 is a sectional view showing a conventional example of a link with an excessive input protection mechanism. The link 3 has pivots 1a, 1b at both ends thereof, and restraints 2a, which hold down the pivots.
2b, with a coiled spring 4 interposed in the center. That is, the link 3 includes two pipes 5 with cross sections (for example, quadrilateral) that can be fitted into each other.
6, a groove is cut parallel to the axis of the link in the common fitting part of each pipe, and a coiled spring 4 is inserted between the seats 7 and 8 inserted at both ends of this groove. The structure is such that 5 and 6 are connected.

FIG. 2 is a schematic diagram of the configuration of a fan-shaped scale indicator using a link having such an excessive input protection mechanism. Input lever 10 transmits a signal from input shaft 11 to output bar 13 via link 12. The pointer 14 corresponds to the rotation angle of the output bar 13.
rotates, the pointer 14 points to the scale marked on the scale plate 15. This is nothing but the operation of an indicator.

Since it is undesirable for the pointer 14 to rotate beyond the range of the scale plate 15 due to excessive input, a stopper 16 is provided on the scale plate 15 to prevent the pointer 14 from rotating excessively. As a result, the link is restrained from rotating, creating compressive stress in the link 12. If the compressive stress becomes excessive, problems such as buckling of the link 12 and breakage of the pointer 14 will occur. In order to prevent this failure, the over-input protection mechanism 17 is employed in the link 12.

(Problem to be solved by the invention) However, according to the conventional link with an excessive input protection mechanism using a spring, when an even more excessive force than expected in the original design is applied, the coiled spring 4 link 12 becomes compressed and can no longer absorb the strain.
There was a fundamental problem in that it buckled and could no longer be used again. Furthermore, if a sufficient margin for excessive input is to be provided, the coiled spring must be made longer, resulting in the disadvantage that the excessive input protection mechanism becomes larger.

The present invention solves the above-mentioned problems and shortcomings, and provides a small link with an excessive input protection mechanism that prevents the link from buckling when excessive input is applied to the link and allows it to be used again. The purpose is to realize the following.

(Means for Solving the Problems) The present invention to achieve such an object includes first and second links that are coupled to each other, and the first link supports this link so as to be movable in the axial direction. In addition to providing a pivot point and a supporting pilot,
The second link is provided with a pivot portion that engages with the pivot portion of the first link, and a support guide whose length from the link shaft centerline gradually increases in the axial direction, The first and second links are connected by a spring.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of the present invention, and shows an excessive input protection mechanism 17 in an enlarged manner. FIGS. 1A, 1B, and 1C are a front view, a plan view, and a front view of the excessive input protection mechanism 17, respectively, showing a state in which the link is bent due to excessive input.

The link 12 consists of a first link 18 and a second link 19 that are connected via an excessive input protection mechanism 17. The first link 18 is the pivot pilot 20
and a bearing pilot 21. The second link 19 has a pivot guide 22 formed with an oval hole having a length l in the axial direction of the second link, and a length d from the X axis, which is the axial center line of the second link, on the X axis. The support guide 23 has a shape that gradually increases along the direction, for example, a circular arc-shaped notch. The spring 24 is connected to a pin 25 provided near the end of the second link of the pivot guide 22 and a support pilot 21.
and connects the first link 18 and the second link 19.

That is, the pivot portion includes a pin 25 for supporting the pivot pilot 20, the pivot guide 22, and the spring 24.
It depends on. Further, the support portion is made up of the support pilot 21 and the child support guide 23.

If no excessive force is applied to the link, the spring 24 will cause the pivot pilot 20 to move to the second position of the pivot guide 22.
The support pilot 2 is located at the end of the link 19 side of the
1 is located at the closed end of the bearing guide 23. In this state, the displacement given to the first link 18 is
It is transmitted as is to the second link 19.

If an excessive force greater than the tensile force of the spring 24 is applied to the link, the pivot pilot 20 will move against the pivot guide 2.
2, and the bearing pilot 2
1 moves along the support guide 23, and the pivot pilot 21 eventually reaches a point where it meets the force of the spring 24.
moves along the pivot guide 22 and stops. Therefore, excessive input is absorbed. When the excessive input is removed, the link length becomes the same length as when no excessive input is applied due to the restoring force of the spring 24.

When the excessive input is extremely large, the amount of movement of the pivot pilot 20 within the pivot guide 22 becomes large as shown in FIG. It comes into contact with the right end of the support guide 22 and cannot move any further. While the first link 18 moves by a length l, the support pilot 21 moves along the circular arc surface of the support guide 23, so the first link 18 gradually bends in the direction of arrow a, and eventually the support pilot 21 is removed from the open end of the bearing guide 23. Then,
The bearing pilot 21 is drawn towards the pin 25 under the tension of the spring 24. Therefore, the support pilot 21 completely deviates from the support guide 23, and the link 17 is bent around the pivot pilot 20.
Absorbs excessive stress.

The operator easily notices the bend, since the bent link 17 no longer responds. The function of the linkage is easily restored by inserting the bearing pilot 21 of the bent link 17 into the bearing guide 23.

In this embodiment, the first link 18 is provided with a pivot pilot 20 and a support pilot 21, and the second link 18 is provided with a pivot pilot 20 and a support pilot 21.
The pivot guide 22 and the support guide 23 are attached to the link 19 of
However, the configuration of the present invention is not limited to the above embodiment; for example, the first link may be provided with a pivot guide and a support pilot, and the second link may be provided with a pivot pilot and a support guide. But that's fine.

(Effects of the invention) As explained above, according to the invention, a small link with an excessive input protection mechanism that prevents the link from buckling when excessive input is applied to the link and can be used again is realized. can.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged view of a link with an excessive input protection mechanism according to the present invention, in which A is a front view, B is a plan view, and C is a front view of the link bent due to excessive input. FIG. 2 is a schematic configuration diagram showing an example of a device to which the present invention is applied, and FIG. 3 is a configuration front view of a conventional link with an excessive input protection mechanism. 18... Link, 19... Link, 20... Pivotal pilot, 21... Support pilot, 22...
...Pivot guide, 23...Support guide, 24...Spring, 25...Pin.

Claims (1)

[Scope of utility model registration request] The first link includes first and second links that are coupled to each other, the first link is provided with a pivot portion that supports the link movably in the axial direction, and a support pilot, and the second link is provided with the first link. a pivot portion that engages with the pivot portion of the link; and a support guide having a shape such that its length from the link axis center line gradually increases along the axial direction,
A link with an excessive input protection mechanism in which the links are connected by a spring.