JPS597620Y2 - Knob attachment device - Google Patents

Description

[Detailed description of the invention] This invention is designed to minimize the eccentricity of the knob with respect to the shaft even when using an inexpensive knob made of resin, and to make the knob elastically connect the knob and the shaft. To provide a knob mounting device that can integrally fix an elastic body for coupling with an extremely simple structure.

In the past, knobs used for tuning knobs and the like were generally made of turned aluminum, but in recent years, resin or molded ones have been increasingly used due to cost considerations.

Conventionally, in order to attach this type of resin knob to a shaft, a structure 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 also has a D-shaped cross section, is inserted into the center hole 1C of the boss 1a, which has a D-shaped cross section.

At this time, the shaft 2 is made slightly larger than the center hole IC, and the knob 1 and the shaft 2 are elastically coupled by expanding the split groove 1b.

However, in this case, the wall thickness around the boss 1a is not uniform, and furthermore, when fitting onto the shaft 2, the boss 1a is spread out based on the flat surface, so that the flat surface is not uniform as shown in FIG. This variation directly appears as a deviation between the axial center O of the knob 1 and the axial center O' of the shaft 2.

For this reason, especially when a flywheel 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 deformation of the arcuate portion 3a of the metal spring 3 makes the shaft and the knob 1 elastic. It is designed to be combined in a specific manner.

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 collapse due to shrinkage after molding and mold release, and in this case as well, there is a problem that the boss 1a is easily eccentric. Ta.

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 inventors devised a knob mounting device that eliminates these conventional drawbacks, and filed a utility model application on the same date as the present application.

This will be explained with reference to FIGS. 5 to 8.

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

This 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. It consists of shaped protrusions 6C, 6C, and a sloped claw 6d extending from the rear end of the elastic portion 6a toward the arcuate surface.

In the above structure, 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.

After that, when the shaft 5 is press-fitted into the center hole of the boss 4a, the flat surface 5a of the shaft 5 is connected to the two protrusions 5c of the elastic body 6.
, 5c in the same direction.

Therefore, the arc-shaped elastic portion 6a is deformed in the direction in which the groove 6b becomes narrower, and the repulsive force thereof causes the knob 4 and the shaft 5 to be firmly coupled.

Note that the deformation of the elastic portion 3a at this time is caused by the protrusions 5c, 6C.
It is absorbed by the recess in between.

In this way, the boss 4a of the knob is shaped into a cylindrical shape, and a resin elastic body 6 having an arcuate cross section is attached to a part of the boss 4a, and the space between the flat surface of the elastic body 6 and the inner circumference of the boss 4a is By press-fitting the shaft 5 having a partially flat surface 5a into the boss 4a, it is possible to (1) make the boss 4a into an almost completely cylindrical shape, and as a result, the thickness of the circumference can be made uniform; Even if shrinkage occurs after molding and 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 almost no risk that the rib 4b will disrupt the roundness.

) (2) The shaft 5 and the boss 4a are positioned with respect to each other by their arcuate portions, and variations in the flat surface 5a of the shaft 5 are sufficiently absorbed by the deformation of the elastic body 6, so that the dimensions of the flat surface 5a are There is almost no eccentricity caused by variations.

(3) Since a resin or molded product is used as the elastic body 6, it is possible to obtain a smooth fit and strong bond that could not be obtained with metal springs, and there is no need for difficult precision control or rust prevention measures. Become.

(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. .

This excellent effect can be obtained.

However, in such a structure, the elastic body 6 is simply connected to the boss 4.
Since the elastic body 6 is only inserted into the boss 4b, there is a problem that the elastic body 6 easily falls off from the boss 4b or gets lost when the shaft 5 is removed.

Additionally, in devices that generally use this type of knob,
In many cases, the shaft 5 is transported without the knob 4 attached.

At that time, in the case shown in FIGS. 5 to 8 above, the knob 4 and the elastic body 6 are transported separately, and the elastic body 6 is attached immediately before fitting, or they are fixed with adhesive etc. in advance and transported. You must take measures such as

For this reason, there is a problem that transportation and assembly work become troublesome.

The present invention eliminates these drawbacks and provides a knob mounting device that allows the knob and the elastic body to be integrated with one touch, and that does not fall off even when the shaft is removed. .

That is, the present invention includes a knob having a cylindrical boss that is fitted onto a shaft, and an elastic body made of resin that is attached to the boss of the knob, and the elastic body is formed with an elastic section having an arcuate cross section. , a groove formed in the axial direction at the center of the arcuate surface;
A protrusion formed in the axial direction on both sides of the flat surface of the elastic part, and a protrusion formed integrally with the elastic part at an angle of about 90 degrees or less at the rear end of the elastic part, and a part of the protrusion is formed in the center of the boss. and a locking piece that is larger in shape than the hole, and the elastic body is fitted into a rotation prevention rib provided with the groove in the axial direction of the inner wall surface of the boss, and the locking piece is bent. The flat surface of the shaft inserted into the center hole is pressed against the protrusion of the elastic body.

In this way, the elastic body can be prevented from falling off by the locking piece provided on the elastic body while maintaining the effects of the structure shown in FIGS. 5 to 8.

An embodiment of the present invention will be described below with reference to FIGS. 9 to 13.

In FIGS. 9 to 13, the same functional parts as in FIGS. 5 to 8 are designated by the same reference numerals, and their explanations will be omitted.

6e is the angle θ formed between the rear end of the elastic body 6 and the elastic part 6a.
The length of the locking piece 6e in the vertical direction is α from the diameter D of the center hole 4C of the boss 4a, as shown in FIG. It is shaped so that it is as long as possible.

Therefore, as shown in FIG. 11, when the elastic body 6 is press-fitted into the center hole 4C while bending the locking piece 6e by an angle β corresponding to the length α, the claw 6d engages with the tip of the boss 4a. At the same time, the locking piece 6e tries to return in the direction of arrow A in FIG.

Therefore, the lower end of the retaining piece 6e is strongly pressed against the inner wall surface of the boss 4a, and as a result, the elastic body 6 is integrally attached to the knob 4.

Therefore, even when the shaft 5 is removed, the elastic body 6 does not fall off, and since it can be easily integrated in advance, transportation and knob attachment operations can be carried out extremely efficiently.

In addition, as shown in FIG. 13, the locking piece 6e is made so that both sides in the lateral direction are larger than the diameter D of the center hole 4C by α, so that when the elastic body 6 is compressed, the entire locking piece 6e may be curved in an arch shape in the lateral direction as shown in FIG.

In this way, more stable fixation can be achieved than in the case shown in FIG.

As mentioned above, the water device consists of a shaft with a flat surface on a part of its outer periphery, a knob with a cylindrical boss that fits into this shaft, and an elastic body made of resin that is attached to the boss of the knob. The elastic body has 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. and a locking piece integrally formed at the rear end of the elastic portion at an angle of approximately 90 degrees or less with the elastic portion, and a portion of which is shaped larger than the center hole of the boss; The elastic body is inserted into the center hole of the boss with the groove fitting into the anti-rotation rib provided in the axial direction of the inner wall surface of the boss and the locking piece being bent, and the elastic body is inserted into the center hole. Since the flat surface of the shaft is brought into pressure contact with the protrusion of the elastic body, the following excellent effects can be obtained.

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

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

(2) The shaft and the 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 due to variations in the dimensions of the flat surface is unlikely to occur. do not have.

(3) Since a resin molded product is used as the elastic body, it is possible to obtain a smooth fit and strong bond that cannot be obtained 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. .

(5) A locking piece is provided integrally with the elastic body, and by bending this locking piece within the center hole of the boss, a portion of the locking piece engages with the inner wall of the center hole like a wedge. The elastic body can be securely fixed to the knob with an extremely simple operation, and it can be prevented from falling off when the shaft is removed, and the knob can be easily transported or attached to the shaft.

[Brief explanation of the drawing]

Figures 1 and 2 are a perspective view and a front view of essential parts of the conventional example, Figures 3 and 4 are an exploded perspective view and a sectional view of the conventional example, and Figures 5 and 6 are the premises of the present invention. 7 and 8 are side sectional views and front sectional views of the main parts thereof, and FIGS. 9 and 10 are used for one embodiment of the present invention. A perspective view and a sectional view showing the elastic body, FIG. 11 is a sectional view for explaining the installation work of the elastic body, FIG. 12 is a rear view of the elastic body of the above embodiment,
FIG. 13 is a rear view of an elastic body in another embodiment. 4... Knob, 4a... Interval boss, 4b... Curved anti-rotation rib, 5... Shaft, 5a... Curved flat surface, 6... Curved elastic body, 6a...・・・Elastic part, 6b・
Curve/groove, protrusion, 6d...claw, 6e...curved locking piece. 6C...

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 knob, the elastic body being an elastic section having an arcuate cross section; a groove formed in the axial direction at the center of the arcuate surface; protrusions formed in the axial direction on both sides of the flat surface of the elastic section; and a rear end of the elastic section. A locking piece is formed integrally with the elastic part at an angle of about 90 degrees or less, and a part of the locking piece is shaped larger than the center hole of the boss, and the elastic body is connected to the groove inside the boss. The locking piece is inserted into the center hole of the boss in a state where it is fitted into the anti-rotation rib provided in the axial direction of the wall and is bent, and the flat surface of the shaft inserted into the center hole is inserted into the elastic body. A knob mounting device that presses against the protrusion.