JPH0221283Y2 - - Google Patents

Description

[Detailed Description of the Invention] The invention of the present application relates to an improvement of an elastic ball caster.

As a conventional example, there is, for example, an elastic ball caster described in Japanese Utility Model Application Publication No. 55-131802 (hereinafter referred to as Conventional Example 1) already provided by the creator of the present invention. As shown in FIGS. 1A and 1B, a receiving body 3 having an annular groove 2 with a C-shaped cross section has an opening surface of the groove facing the upper surface of the running ball 1, and a large number of small holes arranged in the groove. Each of the balls is brought into contact with the outer periphery of the ball and the annular groove, and the lower end of the outer surface of the elastic flexible member 6 is placed on the cylindrical body 5 which covers the outside of the receiver 3 and receives a load from above, and the upper end thereof is placed on the receiver 3. They are connected together. In this configuration, the cylinder 5 receives a load from above, and when a horizontal force F acts, the ball 1 receives road surface resistance and rolls F'. At the same time, the elastic deflection member is deflected, and this deflection creates a trail t, with most of the load acting on the rear side (to the right in the figure) of the annular groove of the receiver. The small ball 4 in the groove near the pole of the ball where this load is applied rolls as the ball rolls, but this rolling f causes it to slide in the groove in a direction perpendicular to the tangential direction along the groove. It turns out. Since this sliding frictional resistance (thrust) increases due to the load from above, the running resistance of the balls rolling together with the small balls also increases significantly, reducing their running performance.

Therefore, in the present application, the reason why the small balls 4 caused sliding friction in the annular groove is that the surface including the centers of the small balls arranged in the annular groove (this is referred to as an annular groove surface or annular surface) is not a horizontal surface. Taking note of this fact, the annular groove surfaces were arranged perpendicularly opposite to each other on the left and right sides of a central vertical plane S that includes the traveling direction F of the ball. That is, as shown in Fig. 2A and B, the center vertical plane S of the ball including the running direction (direction of horizontal force F)
A receiver 3 having an annular groove 2 is placed oppositely on the left and right sides with the ball 1 in between, and when the ball rolls in the direction F, the small balls that roll in contact with the ball roll and circulate within the groove. This allows both the ball and the small ball to be in a rolling state with no sliding friction. Note that 1 in the figure
0 is a cylindrical body with a support shaft 12 erected at the upper end and a bearing at the base of the support shaft that receives the load from above.Although not shown, an elastic member is inserted between the cylindrical body and the receiver as described later. It is assumed that

Next, the operation of the present application will be explained. As shown in Fig. 8A, when the cylinder receives a load and the annular groove surface inclines in the running direction or in the direction of the horizontal force F, when the ball rolls in the direction of F, the annular groove in the front as shown below. f ₁ due to small ball, f ₂ due to small ball in rear annular groove
A thrust of is applied to the receiver, and the elastic member is deflected to produce a trail t such that f ₁ <f ₂ . At this _time , the receiver and cylinder rotate in the direction of arrow R ₂ + R ₁ due to the thrusts of f 1 and f ₂ , and when the annular groove surface aligns with the direction of F as shown in the imaginary line, the rotation stops. , the ball and the small ball roll in the direction F as shown in FIGS. 2A and B, the small ball rolls smoothly along the annular groove, and the cylindrical body runs in the direction F. Therefore, even if Conventional Example 1 cannot be used due to too much sliding friction, the present invention can be used as an elastic ball caster with comfortable castability.

Furthermore, in the present application, as shown in FIG. 8B, if the annular groove surfaces arranged symmetrically and parallel to the vertical center plane S of the ball 1 are located at right angles to the horizontal force F, even if a trail occurs, f ₁ . , f ₂ ... are both in equilibrium, so the direction of rotation of the cylinder is uncertain. To prevent this, annular groove surfaces with a certain angle α to the vertical plane S are provided symmetrically on the left and right sides of S, so that no matter which direction the horizontal force F acts on S, the cylindrical body will not rotate clockwise or counterclockwise. I made it possible to rotate it in either direction.

The operation will be explained below with reference to FIGS. 3A, B, and C and 4A, B, and C. All figures are plan views, and only the parts of the small balls 4 ₁ ..., 4 ₂ ... that receive a large load when a load is applied from above and receive a large frictional resistance with the receiving surface are shown. .

When the horizontal force F acts perpendicularly to the vertical plane S as shown in Figure 3A, a larger load is applied to the small ball 4 ₂ in front of F than to the small ball 4 ₂ in front of F.
The frictional resistance due to rolling is also larger in f ₂ than in f ₁ .
Therefore, the receptors 3 ₁ , 3 received the thrust of f ₁ , f _2
2 and the cylinder 10 rotate as indicated by arrows R ₂ -R ₁ .
Next, when the cylinder rotates until the receiver 3 ₂ on which the small ball 4 ₂ is placed becomes parallel to F, the small ball 4 ₂ is attached to the receiver 3 _2
The frictional resistance is small and R ₂ is almost zero as it rolls on the receiving surface (annular groove) of the ball 3 _{1 .}
There is a thrust based on , and the cylinder rotates only by R ₁ .
(Fig. 3B) As a result, as shown in Fig. C, the direction of F is within the vertical plane S, and the small balls 4 ₁ , 4 ₂ of the receivers 3 ₁ , 3 ₂
The thrust caused by R ₁ and R ₂ are opposite in direction and equal in magnitude, resulting in an equilibrium state. At this time, small ball 4
₁ , 4 ₂ , etc. roll within the receiving surfaces of the receivers 3 ₁ , 3 _{2 ,} respectively, circulate within the grooves, and roll on the outer periphery of the ball 1 .

Next, in the case of Fig. 4A where the annular groove surface of the receiver ₃₂ is vertical in the direction of F, the cylinder rotates clockwise around the support shaft with _R2 = 0 and only _R1 . When the position shown in the figure is reached, f ₁ is approximately zero, and the cylinder rotates in the direction of R ₁ =0 and R ₂ . Then, as shown in diagram C, an equilibrium state is reached in which F is included in the plane of S.

Comparing FIG. 3A and FIG. 4A, there is a so-called consideration point between the position of FIG. 3A and the position of FIG. 4A, since the rotating directions of the cylinder 10 are opposite to each other. However, at this point, since each annular groove surface has an inclination angle α with respect to the vertical plane S, each annular groove surface has a different inclination angle with respect to the vertical plane that contains the horizontal force F at that point. Since there is a difference in the rolling resistance of the small balls, the inclination angle
The cylinder rotates to either R ₁ or R ₂ , whichever is larger,
Regardless of whether the rotation is clockwise or counterclockwise, the cylindrical body rotates around the support shaft until the thrust is balanced, and then the thrust is balanced and stable and smooth rolling of the balls and small balls occurs. Swells. That is, the balls roll on the road surface in the traveling direction, and the small balls roll along the grooves and circulate in the annular grooves. In this way, no matter what direction F acts, the cylinder rotates around the support shaft to the equilibrium position shown in FIG. 3C or FIG.

As mentioned above, in the case of Fig. 3 C, when the balls roll and travel in the direction F, the moment R 1 due to the thrust of the small balls 4 ₁ ... of the receiver 3 ₁ and the moment R _{1 due to the thrust of the small balls 4 1} ... of the receiver 3 ₂
Moment R ₂ due to the thrust of the small ball 4 ₂
are in equilibrium in opposite directions. If the inclination angle α of the receiver 3 ₁ with respect to S becomes smaller, the thrust R ₁ when the small balls 4 ₁ roll will become smaller, and the receiver 3 ₂
The inclination angle α with respect to S becomes larger, and the small ball 4 ₂
When the ... rolls, the thrust and R ₂ increase, and the cylinder attempts to rotate and restore itself to an equilibrium position. Even if the inclination angle α of the receiver 3 ₂ is to become smaller, the inclination angle α of the receiver 3 ₁ becomes larger and the cylinder attempts to rotate to the equilibrium position, and the cylinder remains in stable equilibrium. kept in position. Therefore ball 1
can roll and travel stably and balanced in the direction of F. The same applies to the case of FIG. 4C.

The annular groove shown in FIG. 2 already described and the arcuate groove shown in Conventional Example 2 described later are both arranged symmetrically and parallel to the vertical plane S. In this case, when the groove surface on one side is slightly inclined to F, the groove surface on the other side is also slightly inclined, and the thrust when the small ball (rolling ball) rolling in the groove rotates the cylinder in one direction. Each groove surface tries to match the S surface, but if the rotation slightly exceeds the S surface, the thrust of the small ball tries to rotate in the opposite direction, resulting in the rolling direction or running direction of the ball or cylinder. may rotate or run unsteadily to the right or left and they are not automatically constrained. The rotation of the cylinder due to the thrust of the small ball in the annular groove on one side cannot be controlled by the thrust of the small ball in the annular groove on the other side.

The plane containing the centers of the small balls 4 arranged in the annular groove 2 has an inclination angle α with respect to the vertical plane S, as shown, and an inclination angle β with respect to the horizontal plane. The inclination angle β is set so that the position above the small ball in the annular groove is close to the upper pole of the ball, so that when a load is applied from above, the small ball gets caught between the circumferential surface of the ball and the groove and rolls. The purpose is to prevent the ball from being obstructed, and to keep the lower position of the small ball upward from the ground surface to avoid obstacles on the ground as the ball travels.

Here, when compared with the conventional example described in, for example, Japanese Patent Publication No. 35-4018 (hereinafter referred to as conventional example 2), conventional example 2 has the following as shown in FIG.
A cylindrical ball holder 10', a rolling ball 1' at an eccentric position (trail) t ₀ of the cylindrical ball holder, and left and right antipodals with the center sandwiched between the vertical plane including t ₀ and the center of the rolling ball. It consists of a large number of rolling balls 4' that roll in arcuate grooves 2' and 2' provided in the same direction, and devices 17' and 17'' that support the center and outer circumference of a cylindrical ball holder. The numbers from which the darts are removed are made to match the numbers of the corresponding members of the present application.This configuration is applicable to the elastic deflection member 6 of the present application.
This invention is fundamentally different from the present application in that it lacks the constituent members corresponding to the above. Further, in Conventional Example 2, a trail is provided from the beginning, but in the present invention, a trail is not provided in advance because a horizontal force acts, and a trail is automatically generated by road surface resistance and deflection of an elastic flexible member.

Therefore, regarding the effect, in the present application, when a horizontal force F acts, a trail is generated in the direction of F, and the ball travels in that direction, and the ball travels because the cylindrical body into which the ball is inserted is not eccentric to the ball. Never stray from the ball's running line. The whole travels straight in the direction of the horizontal force F. (Fig. 8A) On the other hand, according to Conventional Example 2, when a horizontal force F acts (Fig. 7), the holder rotates around the center O'' of the rolling ball due to a moment corresponding to the eccentricity t ₀ × F. The rolling ball rolls on the road surface at a position where the eccentricity t ₀ coincides with the direction of F. At this time, the rolling ball on the rolling ball also rolls along the arcuate groove, and the rolling ball moves in the direction of F. As the ball travels in the direction, the holder moves along the travel line of the rolling ball.As shown in the figure, a hemispherical recess into which the rolling ball fits is provided at an eccentric position within the holder, so that the ball travels smoothly. The moving area occupied by the holding body of the slider is significantly larger than the running area occupied by the rolling ball. Conventional Example 2
When the size of the rolling ball is equal to the size of the ball of the present application, the size of the moving area where the holding body and the cylinder travel on the traveling line can be seen by looking at the difference between them in Figure 7 and Figure 8A. Can be done. Furthermore, since the holding body of Conventional Example 2 is larger than the cylindrical body of the present application, the bearings 17' and 17'' supporting the holding body are also similar to the bearing 1 of the present invention.
It has a larger diameter than 7. Therefore, the rotational resistance for their rotation is significantly greater in Conventional Example 2 than in the present invention. For this reason, the rotation of the holding body relative to the predetermined eccentricity becomes slow, and sometimes the rotation becomes impossible. On the other hand, in the present invention, a slight play in the bearing due to the provision of a small-diameter bearing increases the trail due to deflection, which makes the rotation of the cylindrical body more agile due to the thrust of the small ball. Further, since the rolling ball 4' of Conventional Example 2 is configured to circulate and roll in the arcuate groove 2' and an annular recess perpendicular thereto, it is subjected to large rolling resistance at the connecting portion between the arcuate groove and the annular recess. However, according to the present application, since the balls roll in an annular groove, the rolling resistance during circulation is small. This difference in rolling resistance increases as the rolling circulation speed increases.

Therefore, Conventional Example 2 and the present application are significantly different in structure and associated effects.

In view of the existence of the above-mentioned conventional examples, the technical content of the present application has been realized as shown in the embodiments shown in FIGS. 5 and 6. That is, 1 is a ball that can roll in any direction,
Reference numeral 3 denotes a receiver having an annular groove 2 having a C-shaped cross section, and the receiver is arranged oppositely on the left and right with the ball in between, with the opening of the groove facing the outer periphery of the ball, and a small ball 4 in contact with the outer periphery of the ball is placed in the groove. A large number of small balls are arranged so that each small ball rolls along the groove and circulates within the annular groove.
13 is a cylindrical body made of an elastic member formed in a bellows shape, and the lower inner surface has a downwardly facing bowl-shaped hemispherical surface, and a semi-annular groove 1 into which the outer periphery of the receiver 3 is inserted.
4 is provided. The cylindrical body 13 is bent into a bellows shape halfway up its height, and its bending form consists of an upper bent part 13' bent downward from the top and a lower bent part 13'' bent upward from the bottom, as shown in the figure. This bent portion allows the cylinder to bend under the load W from above, and provides sufficient rigidity to withstand collapse due to the pressing force F from the side.The upper end of the receiver is The circumferential edge of the collar-shaped bearing receiving plate 15 is glued to the inner corner of the slightly hanging lower surface.A support shaft 16 is suspended from the center of the upper surface of the bearing receiving plate 15, and a thrust bearing is attached to the base of the supporting shaft 16. 17
is provided, and the upper base plate 18 of the thrust bearing is attached to the lower surface of the fixed part 19. Further, as described above, the annular groove surface has an inclination angle α with respect to the vertical plane S, and an inclination angle β with respect to the horizontal plane.

As described above, according to the present application, there is no eccentricity (trail) between the grounding point of the ball and the grounding point of the support shaft, but by providing the bellows-shaped cylinder, the trail is created in the direction of the horizontal force F. It is possible to provide an elastic ball caster that has caster properties that allow it to roll and roll in any direction, and that also has smooth running properties. In conventional casters, the eccentric portion moves blindly around the support shaft, creating a wide dangerous space that not only gets in the way but also lacks aesthetic appeal. However, according to the present invention, the cylindrical body provided at the end of the leg moves silently in any direction due to the rolling of the ball at the lower end, thereby eliminating the drawbacks of the conventional caster. The above cylindrical body is obtained by omitting the cylindrical body 7 of Conventional Example 1, and is preferable because the shape space and operating space are saved as a whole, and the cylinder body is compact and has a good design.

The material of the ball may be steel, light alloy, or synthetic resin, and if it is small in diameter, it is solid, but if it is large in diameter, it is hollow. To make a hollow ball, first make a hemispherical bowl-shaped ball, glue the periphery of the ball to another ball, and then finish the outer shape into a spherical shape. In addition, the cylindrical body can be plastic-processed from a rubber material, and all of them can be mass-produced and can be used in a wide range of applications, from general furniture to transportation vehicles, and are commercially viable and have high practical value.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and FIGS. 1A and B are a side view and a plan view of a conventional elastic ball caster in the direction of the arrows excluding the elastic deflection member, and FIGS. 2A and B are
are a plan view and a side view illustrating the device for improving rolling properties of the present application, FIGS. 3A, B, C and 4A,
B and C are diagrams explaining the castability of the present application, Figures 5A and B and Figures 6A and B are a plan view and partially cutaway front view of an embodiment of the present application, and Figure 7 is a conventional example 2. FIGS. 8A and 8B are diagrams illustrating the castability of the present application. In the figure, 1 is a ball, 3 is a receiver, 4 is a small ball,
10 and 13 are cylindrical bodies.

Claims (1)

[Claims for Utility Model Registration] A ball that can roll in any direction, a support shaft that surrounds the upper outer periphery of the ball, and a support shaft that almost coincides with the vertical center line of the ball at the upper end, and a bellows that extends from the middle of the height. A cylindrical body that is bent into a shape and has flexibility and rigidity against falling as a whole, a bearing provided at the base end of the support shaft that receives the load from the fixed part and rotates the cylindrical body around the support shaft, and the outer periphery of the ball. The annular surface including the annular groove is symmetrical with respect to the vertical plane S including the center line of the ball at a certain angle α, and the annular surface is symmetrical with respect to the vertical plane S including the center line of the ball. a pair of receivers inserted into the inner surface of the cylindrical body so as to have an inclination angle β with the ground plane and facing near the upper pole of the ball; It consists of a large number of small balls arranged along the groove, and the small balls also roll along the opening of the groove in contact with the balls rolling in the running direction, and the thrust of this rolling is applied to the cylinder, causing the cylinder to roll. Elasticity characterized by rotating the body around the support shaft, and at the position where the thrust is balanced, the ball rolls in the running direction, and the small ball also rolls along the groove and circulates in the annular groove. Ball caster structure.