JPS6343124Y2 - - Google Patents

Description

[Detailed explanation of the invention] A caster whose running body is a ball (sphere) can freely rotate around the center of the ball in response to forces acting in the lateral direction, but when the load from above increases, the upper surface of the ball Running performance deteriorates due to frictional resistance between the bodies. The ball rolls within a certain range of load, but when the load exceeds it, the lateral force overcomes the frictional force between the road surface and the ball and between the ball and the receiver and pushes the ball. It does not rotate itself.

This invention reduces the frictional resistance between the upper surface of the ball rolling element and the lower surface of the receiver that receives it, thereby increasing the range of load over which the balls roll as much as possible, and exceeding that range. To provide a caster that can move flexibly without running property under a heavy load. However, the object of the present invention is to provide a caster that has the same quick running performance as a normal caster by replacing the ball rolling element with a ball running body having a ball-shaped wheel if necessary.

This will be explained with reference to the illustrated embodiment. Reference numeral 1 denotes a ball rolling element which is a spherical rolling element and can roll in any direction. Reference numeral 2 denotes a receiver (caster body) whose lower surface 4 faces the upper surface 3 of the ball rolling element 1 while receiving the load W from above. is provided with a suitable anti-friction device 5. This embodiment consists of an annular groove 6 formed on the lower surface 4 of the receiver 2 and a large number of small balls 7 that fit into the annular groove 6 and contact the upper surface of the ball rolling element 1. Each small ball 7 rolls into the groove 6. The ball is adapted to move and roll on the surface of the ball rolling element 1.

The receiver 2 has a hemispherical bowl-shaped receiver 8 that receives the ball rolling element 1 via the friction reducing device, and the center of the receiver 8 (of the ball rolling element 1) is located on the upper surface of the front end extending forward. The center of the recess 9 is provided at a position eccentrically forward from the center of the recess 9, and the steering shaft 10 is erected upward from the center of the recess 9. If the point where the ball rolling element 1 contacts the road surface is s, and the point where the center line of the steering shaft 10 falls onto the road surface is t, then st is called a trail and is equal to the eccentricity e mentioned above. When this st is large, the moment that changes the direction of the caster becomes large. Steering shaft 10
Although it can be provided integrally with the receiver 2, it is usually provided separately and fixed at its base end.

In addition, the steering shaft 10 has thrust bearings 11,1
Fixed part 13 that receives load W from above through 2
A skirt-shaped wall 15 is attached to the lower edge 14 of the bowl-shaped receiving part 8 of the receiving body 2 with a gap between the ball rolling element 1 and the lower end of the wall 15. is made shorter at the front end and longer at the rear end, tilted forward and backward, and the receiver is slightly raised so that the ball rolling element 1 can be taken out forward. A receiving ball 16 for pushing and moving is provided, and bearings 19 for receiving the shaft 18 of the ball traveling body 17 are provided on each of the left and right side walls of the wall.
19 are provided. As described later, the receiving ball 16 can be replaced by a small ball 7 disposed at the rear end of the groove 6, or both can be simply a protrusion.

A load W is applied to the ball caster configured in this way.
When a lateral force F acts on the ball rolling element 1, a rotating moment M is generated around the contact point s on the road surface of the ball rolling element 1. This moment causes the caster to turn around s, and the ball rolling element rotates around the contact point s on the road surface. Start driving in the direction. At this time, when the frictional resistance between the upper surface of the rolling element and the lower surface of the receiving part is small, that is, when the frictional force that causes the small balls interposed on both sides to roll is small and the rolling element is suitable for rolling on the road surface, the rolling element travels in a rolling manner, causing the caster to travel in the direction of F. When the load from above increases and the frictional resistance on the upper surface of the rolling element increases, the rolling state stops, and the receiving ball 16 or protrusion provided on the inner surface of the rear wall of the skirt-like wall pushes the rolling element from behind. Move the rolling elements in the direction of F. If the force F is less than the frictional resistance, the caster does not move and stops at that position.

For example, when used on the leg end of a chair, such a ball caster allows the chair to move freely when there is no load on the seat, but when a person is seated and the weight of their body is applied to the leg end of the chair. The chair stays in that position and can be used when you don't want the chair to move randomly. At this time, if a larger lateral force F is applied, the rolling elements do not roll, but move in the direction of F. In order to make this caster work like a normal caster regardless of the load W, the ball rolling element 1 can be replaced with a ball running element 17. To perform this replacement, first lift the receiver upwards, push the ball rolling element from behind, take it out from the inclined front end of the skirt-like wall, and place it on the axles 18, 18 of the ball running body 17 and the bearings provided on the side wall of the wall. It is.

For example, as shown in FIG. 3, the ball running body 17 has a ball-shaped wheel portion 20 and one end of which is connected to a bearing 19 on the side wall.
A pair of axles 18, 1 are fitted with each other and are biased radially from the center of the wheel portion by a spring 21 with the other ends facing each other.
8, and each of the axles 18, 18 is slidable in the shaft hole 22 of the wheel portion 20 via a thrust bearing 23. To fit this into the bearing 19 of the skirt-like wall, push the free end of the axle 18 toward the center of the wheel part 20 against the spring 21, and push it along the inner surface of the wall to the bearing 19. The reaction force causes the two to fit together. Note that it can be easily removed by reversing the above procedure. In the case of the embodiment shown in FIG. 4, the wheel portion and the axle may be integrated, but the end of the axle may be received by a bearing.

The material of the ball running body should be slightly harder than the road surface on which it will be used, such as steel, light alloy, hard plastic, etc.
You can choose rubber or other suitable material. The outer diameter should be somewhat smaller than the outer diameter of the ball rolling element to be replaced, or it should be an elliptical rotating element. If the diameters are the same, the pre-warming bearing 19 may be provided at a position slightly lower than the center of the rolling element 1.

Due to its shape, the material of the receiver 2 is not limited to steel or light alloy, but may be made of flexible plastic, and one feature of the present invention is that the receiver 2 as a whole is flexible under load. In other words, in a ball caster, the spacing between the bearings 19, 19, which receive the shaft ends of the ball running body of the receiver, can be made significantly wider than in the case of conventional wheel running bodies. When bent, the inner surface of the receiver comes into contact with the outer periphery of the traveling body, limiting the traveling performance. Moreover, the material can be easily mass-produced by press processing, extrusion molding, etc., taking advantage of its flexibility.

In addition, the anti-friction device is not limited to the case shown in Fig. 1, but as in the embodiment shown in Fig. 2, the skirt wall and the receiving part are integrally molded, and the lower edge of the wall is inclined back and forth to form the receiving part in which the small balls are arranged. In some cases, the groove shape on the inner surface of the part is a closed curved line. Further, a shafted roller or a shafted ball may be arranged between the receiving portion and the ball rolling element. Alternatively, an appropriate design may be adopted, such as by forming several grooves on the inner surface of the receiving portion and allowing an anti-friction material such as oil, carbon, or resin to accumulate in the grooves. Note that the small balls in the rear grooves of the helmet-shaped grooves receive reaction force when the ball rolling elements are pushed against frictional resistance, so they have the same effect as the receiving balls 16 in FIG. 1. These can be replaced by protrusions as described above. FIG. 4 shows an embodiment in which the helical groove shown in FIG. 2 is replaced with an annular groove that slopes back and forth.

As described above, according to the present invention, the functions of the caster can be expanded compared to the conventional ones, and its usefulness can be significantly increased.

[Brief explanation of drawings]

The drawings show an embodiment of this invention and are shown in Figure 1A.
B is a top view and a bottom view of a half cutaway of the main project.
2A is a side sectional view of the same, FIG. 2A is a top view and a bottom view of another embodiment of the present invention, and FIG. FIG. 4 is a side sectional view showing another embodiment of FIG. 2. In the figure, 1 is a ball rolling element, 17 is a ball running (wheel) body, 2 is a receiver, 5 is an anti-friction device, and 10 is a steering shaft.

Claims (1)

[Scope of utility model registration request] The lower surface of the receiving part of the receiving part (caster body) that receives the load is exposed to the upper surface of the ball rolling element through the anti-friction device, and the upper surface of the front end extending forward of the receiving part is exposed from the center of the ball rolling element forward. A steering shaft is erected at an eccentric position separated by a distance, a wall is formed that extends downward from the peripheral edge of the receiving part to the ball rolling element with a gap, and the ball rolling element is moved forward by applying the ball rolling element to the rear inner surface of the wall. A protrusion is provided for pushing, the lower edge of the wall is tilted back and forth so that the receiver can be lifted and the ball rolling element can be taken out, and bearings are provided on each of the left and right walls to receive the shaft end of the ball rolling element. A ball caster characterized in that the ball rolling element can be replaced with a ball running element.