JPS5847447Y2 - Knob attachment device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a clamp attachment device that minimizes eccentricity of the knob with respect to the shaft even when an inexpensive knob made of resin is used.

Conventionally, the horns used for synchronized meetings were made of ground aluminum.
It used to be common to use molded materials, but in recent years resin molded products are increasingly being used due to cost considerations.

Conventionally, in order to attach this type of resin knob to a shaft, a configuration as shown in FIGS. 1 to 4 has been adopted.

In other words, the ones in FIGS. 1 and 2 are the boss 1a of the knob 1.
A shaft 2, which is also formed in a cross section, is inserted into a central hole 1c of the boss 1a, which has a groove 1b formed in the cross section.

At this time, the knob 1 and the shaft 2 are elastically coupled by making the shaft 2 slightly larger than the center hole 1c and pushing out the split groove 1b.

However, in this case, the wall thickness around the boss Ha is not uniform, and when fitting onto the shaft 2, the boss 1a is pushed apart with respect to the flat surface, so that the wall thickness around the boss Ha is not uniform as shown in FIG. The surface variation directly appears as a deviation between the axis 0 of the trench 1 and the axis Ob of the shaft 2.

For this reason, especially when a fly hole or the like is provided on the shaft 2, smooth rotation cannot be expected due to the misalignment of the axis.

On the other hand, in the case shown in FIGS. 3 and 4, a substantially U-shaped metal spring 3 is attached to the boss 1a of the knob 1, and the shaft and the knob 1 are connected by deforming the arcuate portion 3a of the metal spring 3. It is designed to be elastically connected.

However, in this case, since the boss 1a has a shape that is far from a perfect circle, the roundness of the boss 1a is likely to be lost due to shrinkage after molding and mold release, etc., and in this case as well, there is a problem that the boss 1a is easily eccentric. .

Moreover, when the metal spring 3 is used in this manner, it becomes difficult to control the accuracy of dimensions, shape, heat treatment, etc., and there are disadvantages in that rust prevention measures are also required.

The present invention provides a knob mounting device that eliminates these conventional drawbacks.

An embodiment of the present invention will be described below with reference to FIGS. 5 to 8.

In the figure, 4 is a cylindrical boss integrally molded with resin, 4a is a cylindrical boss formed with a substantially uniform thickness around the circumference, 4b is a rotation prevention rib formed in the axial direction of the inner wall surface, and 5 is a shaft. , 5a is a flat surface formed on a part of its outer periphery, and 6 is an elastic body integrally formed of resin.

The elastic body 6 includes an elastic part 6a having an arcuate cross section arranged along the inner wall surface of the boss 4a, a groove 6b formed in the axial direction at the center of the arcuate surface, and a groove 6b formed in the axial direction on both sides of the flat surface. The elastic part 6a is made up of projecting rims 6c, 6c, and an inclined claw 6d extending from the rear end of the elastic part 6a toward the arcuate surface.

In the above configuration, when the groove 6c of the elastic body 6 is fitted into the rib 4b of the boss 4a, the elastic body 6 is inserted into the center hole of the boss 4a in this state, and the claw 6d is engaged with the tip of the boss 4a. The elastic body 6 is temporarily fixed to the boss 4a.

Thereafter, when the shaft 5 is press-fitted into the center hole of the boss 4a, the flat tlilr 5a of the shaft 5 presses the two protrusions 6c, 6c of the elastic body 6 in the same direction.

Therefore, the arc-shaped elastic portion 6a is deformed in a direction in which the groove 6b becomes narrower, and the repulsive force of the elastic portion 6a firmly connects the housing 4 and the shaft 5.

The deformation of the elastic portion 3a at this time is the protrusion 6c+6
It is absorbed by the recess between c.

As described above, in the present invention, one boss is formed into a cylindrical shape, a resin elastic body with an arcuate cross section is attached to a part of the boss, and the flat surface of this elastic body and the inner circumference of the boss are attached to a part of the boss. Since a shaft having a partially flat surface is press-fitted in between, the following excellent effects can be obtained.

(1) The boss can be made into an almost perfectly cylindrical shape, and as a result, the surrounding wall thickness can be made uniform, so molding,
Even if shrinkage occurs after mold release, it occurs uniformly over the entire circumference.

Therefore, high roundness can always be achieved, and eccentricity due to deformation of the boss can be reliably prevented.

(Note that since the anti-rotation rib 4b may be thin, there is little risk that the roundness will be disrupted by the rib 4b.

) (2) The shaft and boss are positioned with respect to each other by their arcuate portions, and variations in the flat surface of the shaft are sufficiently absorbed by deformation of the elastic body, so eccentricity may occur due to variations in the dimensions of the flat surface. There aren't many.

(3) Since a resin molded product is used as the elastic body, it is possible to obtain smooth fitting and strong bonding that could not be achieved with metal springs, and there is no need for difficult precision control or rust prevention measures.

(4) As a result of the above, even when using inexpensive resin knobs, it is possible to achieve high precision that is almost equivalent to aluminum turning, and we can expect a reduction in price and an improvement in quality. .

[Brief explanation of the drawing]

Figures 1 and 2 are a perspective view and a front view of main parts of the conventional example, Figures 3 and 4 are the same. Figures 5 and 6 are an exploded perspective view and a sectional view of the conventional example. A perspective view P and an exploded perspective view showing one embodiment of the present invention, and FIGS. 7 and 8 are a side sectional view and a front sectional view thereof. 4...Knob, 4a...Boss, 4b.
...Stopper rib, 5...Shaft, 5
a...Flat surface, 6...Elastic body, 6a.
...Elastic part, 6b...Groove, 6c...
... protrusion, 6d...claw.

Claims (1)

[Scope of utility model registration request] A shaft having a flat surface on a part of its outer periphery, a knob having a cylindrical boss fitted to the shaft, and an elastic body made of resin attached to the boss of the slag, the elastic body consists of an elastic section having an arcuate cross section, a groove formed in the axial direction at the center of the arcuate surface, and a protrusion formed in the axial direction on both sides of the flat surface of the elastic section; is inserted into the center hole of the boss while being fitted into the anti-rotation lip provided in the axial direction of the inner wall surface of the boss, and the flat surface of the shaft inserted into the center hole is pressed against the protrusion of the elastic body. A knob mounting device designed to