JPH0466721B2 - - Google Patents

Description

[Detailed description of the invention] Industrial applications The present invention relates to a swing caster.

Prior Art FIG. 5 is a cross-sectional view showing a typical prior art. The rotating caster 1 roughly consists of a base plate 2 and an upper plate 3.
It consists of a crotch fitting 4, a ball pusher 5, and a thrust shaft 6, and is made of, for example, metal. A wheel 9 is attached to the crotch fitting 4 by an axle 8. Steel balls 10 and 11 are interposed between the base plate 2 and the upper plate 3, and between the crotch fitting 4 and the ball pusher 5, respectively, and are overlapped with each other, and a nut 7 is screwed onto the thrust shaft 6. separation of each is prevented. Also, steel ball 1
0 and 11, the base plate 2 and the ball pusher 5, the upper plate 3 and the crotch fitting 4 are mutually rotatable around the axis of the thrust shaft 6.

Problems to be Solved by the Invention In the prior art as described above, parts such as the base plate 2, upper plate 3, crotch fitting 4, and ball pusher 5 are made of metal, so they are easily corroded and have problems with durability. Ta. In addition, it was heavy and inconvenient to handle. In addition, there were other problems, such as a metallic sound when turning and high turning resistance under load.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a swing caster that is durable, quiet, has extremely low swing resistance, is lightweight, has a simple structure, and is robust.

Means for Solving the Problems The present invention provides (a) a metal rolling bearing 19 configured with rolling elements 19c interposed between an inner ring 19a and an outer ring 19b;
and (b) a plastic base plate 40, (b1) an outer peripheral surface 19b1 of the outer ring 19b and an upper end surface 19b2.
and (b2) a cylindrical portion 41 that covers the lower end surface 19b3, is insert-molded with the outer ring 19b, and has an inner circumferential surface 41a that becomes larger in diameter toward the bottom; (b2) extends in the radial direction and has an insertion port 43 in the center. (c) The base plate 40 has a mounting portion 42 formed therein;
2, the shaft portion 20b protrudes downward from the inner ring 19a, and the metal thrust shaft 20 has an external thread 20c formed at the lower part;
a ring-shaped first washer 37 whose upper end surface abuts on 9a3 and extends radially outward; (e) a plastic fork 18; (e1) an axis line of the thrust shaft 20 from the lower end 40a of the base plate 40 (e2) a flange portion 18a extending in the radial direction with an interval d in the direction; and (e2) a top portion 30 continuous to the flange portion 18a,
It has a hole 32 through which the thrust shaft 20 is inserted, an upper part 30a of the top part 30 contacts the lower end surface of the first washer 37, a slope 30b contacts the inner peripheral surface 41a of the cylindrical part 41, and a lower part of the hole 32. (e3) a pair of legs 31 extending downward from the flange 18a, the axle being perpendicular to the axis of the thrust shaft 20 at a position offset from the axis; 34 insertion holes 3
(f) a fork 18 including a leg portion 31 which has a fork 31 and supports the wheel 35 rotatably on both sides of the wheel 35 by the axle 34; Place 30c
(g) a ring-shaped second washer 38 whose upper end surface is in contact with the bottom of the thrust shaft 20 and which extends radially outward;
(h) A plastic cap 44 that fits into an insertion hole 43 formed in a mounting portion 42.

Effect According to the present invention, the inner ring of the rolling bearing is held between the top of the fork that pivotally supports the wheel having a horizontal axis and the head of the thrust shaft inserted through the top, and is held by the nut. Tightened. The outer ring of the rolling bearing is sandwiched and fixed by integral insert molding with the base plate. Therefore, the fork can be fixed to the base plate via the rolling bearing, and the fork can rotate relative to the base plate around the axis of the rolling bearing.

Embodiment FIG. 1 is a sectional view of a swing caster 15 having a configuration that is a premise of the present invention. The swing caster 15 is
It includes a base plate 16, a socket 17, a fork 18, a thrust shaft 20 serving as a rolling bearing 19, and a nut 21. The base plate 16 is made of plastic and includes a mounting portion 22 and a cylindrical portion 23. The cylindrical portion 23 is formed near the center of the attachment portion 22 and faces downward.
An external thread 24 is formed on the outer peripheral surface of the cylindrical portion 23 .
The inner diameter of the cylindrical portion 23 is selected to be approximately equal to or slightly larger than the outer diameter of the rolling bearing 19, which will be described later. A recess 25 is provided on the lower surface of the mounting portion 22 in the cylindrical portion 23.
is formed, and a head 20a of a thrust shaft 20, which will be described later, is inserted. The inner diameter of the recess 25 is the same as that of the thrust shaft 20.
The outer diameter of the head 20a is selected to be slightly larger than the outer diameter of the head 20a. A plurality of attachment holes 22a are arranged in the attachment portion 22.

The socket 17 is formed from plastic;
It consists of a cylindrical portion 26 and an inward flange 27. Cylinder part 2
An internal thread 28 is formed on the inner peripheral surface of 6. The internal thread 28 is screwed into an external thread 24 formed in the cylindrical portion 23 of the base plate 16. The inward flange 27 has a slope 27a that is formed downward into a truncated cone shape.

The fork 18 is made of plastic, for example, and includes a top portion 30 and a pair of legs 31.
It is roughly formed into an inverted U shape when viewed from the right side in FIG. The top portion 30 has a slope 3 formed in the shape of a truncated cone.
0a, and the slope 30a faces the slope 27a of the inward flange 27 of the socket 17. A thrust shaft insertion hole 32 is formed in the top portion 30 . An insertion hole 33 is formed near the free end of the leg 31,
An axle 34 is provided to rotatably support a wheel 35.

The thrust shaft 20 consists of a head 20a and a shaft portion 20b, and an external thread 20c is provided near the end of the shaft portion 20b.
is formed. A nut 21 is screwed into the outer thread 20c of the shaft portion 20b of the thrust shaft 20. Thrust shaft 2
The outer diameter of the shaft portion 20b is selected to be approximately equal to or slightly smaller than the inner diameter of a rolling bearing, which will be described later.

The rolling bearing 19 is made of stainless steel, for example, and has an inner ring 19a and an outer ring 19b.
is intervened.

FIG. 2 is a diagram showing a mounting structure between the rolling bearing 19 and the fork 18. The rolling bearing 19 and the fork 18 are roughly fixed by a thrust shaft 20 and a nut 21. The shaft portion 20b of the thrust shaft 20 is inserted into the inner ring 19a of the rolling bearing 19.
Further, the shaft portion 20b of the thrust shaft 20 has a first washer 37
The thrust shaft insertion hole 32 provided in the top portion 30 of the fork 18 is inserted through the fork 18 . Furthermore, the shaft portion 20b of the thrust shaft 20 is inserted through the second washer 38,
Screw into nut 21. At this time, rolling bearing 1
The inner ring 19a of No. 9 is held between the head 20a of the thrust shaft 20 and the first washer 37, and further,
The top part 30 of the fork 18 has a first washer 37 and a second washer 37.
It is held between the nut 21 and the washer 38. Therefore, the inner ring 19a of the rolling bearing 19 and the fork 18 are integrally fixed.

FIG. 3 is a diagram showing the mounting structure between the base plate 16 and the socket 17. The base plate 16 and the socket 17 are connected to an external thread 24 provided in the cylindrical portion 23 of the base plate 16.
and an internal thread 28 provided in the cylindrical portion 26 of the socket 17 are screwed together to be fixed. At this time, the rolling bearing 19 is placed inside the cylindrical portion 23 of the base plate 16.
By inserting the outer ring 19b of the rolling bearing 19, the outer ring 19b of the rolling bearing 19 is clamped and fixed between the mounting portion 22 and the inward flange 27 of the socket 17. Therefore, the aforementioned rolling bearing 19 and fork 18
When fixing, the socket 17 is placed on the top 30 of the fork 18 with the inward flange 27 facing the same, and a first washer is placed along the inner peripheral surface of the inward flange 27, and the thrust shaft 20 is inserted through the socket 17. Shi, Natsu 2
The base plate 16 and the fork 18 are fixed via the rolling bearing 19 by screwing the socket 17 and the base plate 16 together and rotating the socket 17 and the base plate 16 mutually. Therefore, the base plate 16 and the fork 18 are
Reciprocally rotatable around the axis of the thrust shaft 20, the rolling bearing 19 can receive radial force and thrust force. Further, at this time, the head 20a of the thrust shaft 20 is inserted into the recess 25 of the base plate 16, so that the head 20a of the thrust shaft 20 and the mounting portion 22 of the base plate 16 are disconnected. Desired contact is prevented.

As described above, the inner ring 19a of the rolling bearing 19
can be fixed to the fork 18 by the thrust shaft 20 and the nut 21, and the outer ring 19b of the rolling bearing 19 can be fixed between the base plate 16 and the socket 17. Therefore, the base plate 16 and the socket 17 and the fork 18 rotate relative to each other.
There is no undesired contact between the two and no sliding noise. Furthermore, each component such as the base plate 16, socket 17, fork 18, rolling bearing 19, and thrust shaft 20 can be manufactured separately. In particular, the base plate 16, the socket 17 and the fork 18
is easy to manufacture because it is made of plastic;
It is possible to obtain a lightweight and beautiful appearance.

The base plate 16 includes a rolling bearing 19 and a thrust shaft 20.
The head 20a of the roller bearing 19 and the thrust shaft 20 is protected from water intrusion from above.
Improves durability, corrosion resistance and chemical resistance. Further, the top portion 30 of the fork 18 is connected to the first washer 3
7. Because it is held by the second washer 38,
The attachment strength of the fork 18 to the thrust shaft 20 and the nut 21 can be improved.

FIG. 4 shows a swing caster 1 according to an embodiment of the present invention.
5a is a sectional view of FIG. The present invention is similar to the above-mentioned premise, and corresponding parts are given the same reference numerals. In the configuration that is the premise of the present invention, the base plate 1
6 and the socket 17 are formed separately, and the base plate 16
The outer ring 19 of the rolling bearing 19 is screwed together with the outer thread 24 of the socket 17 and the inner thread 28 of the socket 17.
b is clamped and fixed. In this example,
The socket is formed integrally with the base plate 40, and the base plate 40 has a cylindrical portion 41 for fixing the outer ring 19b of the rolling bearing 19.
It is formed near the center of the mounting portion 42 facing downward. The base plate 40 is made of plastic, and when the base plate 40 is formed, the outer ring 19b of the rolling bearing 19 is integrally formed and fixed to the cylindrical portion 41 by so-called insert molding. An insertion opening 43 is formed near the center of the mounting portion 42 of the base plate 40, and the inner ring 19a of the rolling bearing 19 and the fork 18
A thrust shaft 20 is inserted to integrally fix the two. The insertion port 43 has a stepped portion 43a that extends outward in the radial direction. After the thrust shaft 20 is inserted into the insertion port 43, a cap 44 made of plastic is fitted to prevent rainwater from entering the insertion port 43. The cap 44 has a flange 44a facing outward in the radial direction, and the flange 44a abuts against the stepped portion 43a of the insertion port 43, thereby preventing the cap 44 from sinking into the insertion port 43. . Shaft portion 20b of thrust shaft 20
is inserted from the insertion port 43, passes through the inner ring 19a of the rolling bearing 19, and then passes through the first washer 37 to the fork 18.
It is inserted through the thrust shaft insertion hole 32 provided in the top part 30 of the holder, and is further screwed into the nut 21 via the second washer 38. As a result, the inner ring 1 of the rolling bearing 19
9a and fork 18 are integrally fixed. With this configuration, the base plate 40, the fork 18, and therefore the wheel 35 are mutually aligned with the thrust shaft 2.
It becomes possible to rotate around the zero axis. Since the base plate 40 and the outer ring 19b are integrally molded, the outer ring 19b having a large diameter is supported by the large area of the cylindrical portion 41 of the base plate 40. Therefore, even if the base plate 40 is made of plastic, when a large load is applied to the base plate 40, it can sufficiently withstand the load. In addition, rolling bearing 1
The inner ring 19a of No. 9 is supported by its lower end surface being in contact with a first washer 37 having a larger diameter than that of the inner ring 19a.
The first washer 37 is supported at the top of the fork 18, and its area is larger than when the inner ring 19a is directly supported, which reduces the load per unit area and is sufficient even if the fork 18 is made of plastic. can withstand Moreover, the base plate 40 that rotates mutually
and fork 18 are made of plastic, and since they are in contact with the inner circumferential surface 41a and the slope 30b, no unpleasant sliding noise is generated during rotation.

Each of the parts, such as the rolling bearing 19 and the thrust shaft 20, other than commercially available parts, can be manufactured from plastic, and insert molding of the base plate 40 and the rolling bearing 19 can be performed relatively easily.

Effects As described above, according to the present invention, the inner ring of the rolling bearing is clamped and fixed by the head of the thrust shaft and the fork, and the outer ring of the rolling bearing is integrally clamped and fixed by the base plate. be done. With this, the base plate and
The fork and therefore the wheel are mutually rotatable about the axis of the thrust shaft.

In addition, each part can be manufactured from plastic, except for some commercially available rolling bearings, thrust shafts, etc., so that weight and manufacturing costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a swing caster 15 having a configuration that is a premise of the present invention, FIG. 2 is a diagram showing the mounting structure between the bearing 19 and the fork, and FIG. 3 is a diagram showing the mounting structure between the base plate 16 and the socket 17. 4 is a sectional view of a swing caster 15a according to an embodiment of the present invention, and FIG. 5 is a sectional view showing a typical prior art. 15, 15a... Swivel caster, 16, 40...
...base plate, 17...socket, 18...fork,
19... Rolling bearing, 19a... Inner ring, 19b...
...Outer ring, 20... Thrust shaft, 21... Nut, 30
...Top, 32...Thrust shaft insertion hole.

Claims (1)

[Scope of Claims] 1. A metal rolling bearing 19 having a rolling element 19c interposed between an inner ring 19a and an outer ring 19b, and a plastic base plate 40, which includes an outer ring 19b.
A cylindrical portion 41 that covers the outer circumferential surface 19b1, the upper end surface 19b2, and the lower end surface 19b3, is insert-molded with the outer ring 19b, and has an inner circumferential surface 41a that becomes larger in diameter toward the bottom, and a cylindrical portion 41 that extends in the radial direction and has a central A base plate 4 having a mounting portion 42 having an insertion opening 43 formed therein;
0 is inserted into the inner ring 19a, its head 20a forms an outward brim and abuts the upper end 19a2 of the inner ring 19a, its shaft 20b protrudes downward from the inner ring 19a, and an outer thread 20c is provided at the bottom. A metal thrust shaft 20 is formed, and a lower end surface 19 of the inner ring 19a through which the thrust shaft 20 is inserted.
A ring-shaped first washer 37 whose upper end surface abuts a3 and extends radially outward; and a plastic fork 18, which is spaced apart from the lower end 40a of the base plate 40 by a distance d in the axial direction of the thrust shaft 20. A collar portion 1 extending in the radial direction
8a, and a top portion 30 that is connected to the flange portion 18a and has a hole 32 through which the thrust shaft 20 is inserted.
It has a slope 30b that comes into contact with the inner peripheral surface 41a of 1,
A top portion 30 having a concave portion 30c extending downward from the bottom of the hole 32 and a pair of legs 31 extending downward from the collar portion 18a.
It has an insertion hole 33 for an axle 34 perpendicular to the axis of the thrust shaft 20 at a position offset from the axis of the thrust shaft 20, and the wheel 35 can be freely rotated by the axle 34.
a fork 18 including leg portions 31 pivotally supported on both sides of the fork 5; a nut 21 that abuts the lower end surface of the second washer 38 and is screwed into the outer thread 20c of the thrust shaft 20; and a plastic cap 44 that fits into the insertion hole 43 formed in the mounting part 42. A rotating caster characterized by comprising: