JPH05150764A - Caster for piano - Google Patents

Abstract

PURPOSE:To relieve the bending moment acting on a caster wheel receiving member and bearing member and to enhance durability by interposing an oil-less bearing consisting of a self-lubrication material between the caster wheel receiving member and the bearing member. CONSTITUTION:The caster 1 for a piano is constituted of a caster main bearing 2 fixed to the lower part of the piano, a caster spindle 3, the oil-less bearing 4, a thrust washer 5, the caster bearing 6, a caster axle 8 and a caster wheel 9. The oil-less bearing 4 is provided with a self-lubricating surface on its back surface 4C. The self-lubricating surface is formed by depositing a mixture composed of a tetrafluoroethylene resin and lead on the bearing surface. The upper surface 5B of the thrust washer 5 made of a bearing steel in contact with the back surface 4C of the oil-less bearing 4 is finished by grinding. Then, the high-hardness material is used and the material is ground to the smooth surface having high accuracy, by which the friction force generated between the oil-less bearing 4 and the thrust washer 5 the wearing amt. are additionally decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a caster for a piano which is effective in improving reliability and durability.

[0002]

2. Description of the Related Art Heretofore, as casters attached to the lower part of a piano and exhibiting a stable supporting force, for example, Japanese Utility Model Publication No. 59-39044, "Caster for Piano" has been proposed.

As shown in FIG. 5, such a caster 101 for a piano includes a caster main bearing 102 attached to the lower part of the piano 100, a caster wheel bridge 103 rotatably arranged on the lower surface thereof, and a caster wheel bearing 103. The caster wheels 104 are movably supported. Here, the caster main bearing 102 and the caster wheel carrier 103 are connected by a caster main shaft 105 via a caster washer 106 made of brass. The caster washer 106 is arranged substantially concentric with the caster main bearing 102. The caster wheels 104 are supported on the caster wheel bridge 103 by the caster axle 107. The axis of the caster wheel shaft 107 is offset from the axis of the caster main shaft 105 by a distance E101. By providing the offset distance E101, the caster can change its traveling direction and the like. ..

[0004]

By the way, the radius R101 of the above-mentioned conventional caster washer 106 is set to be shorter than the deviation distance E101. Therefore, when the load f acts on the grounding position of the caster wheels, there is no object interposed between the caster wheel carrier 103 and the caster main bearing 102 corresponding to this load working position, so that the caster wheel carrier 103 and the caster main shaft 105 are not present. A relatively large bending moment acts on. This is caster spindle 1
05 and the caster wheel support 103 are deformed, and it becomes difficult to smoothly rotate the caster main bearing 102 and the caster wheel support 103, and the reliability and durability of the piano caster 101 are deteriorated. ..

Further, when the caster main bearing 102 and the caster wheel support 103 are rotated, it is necessary to lubricate the sliding surface with the caster washer 106 in order to suppress the generation of frictional force and the progress of wear. It was. However, since the lubrication performance of lubricating oil and the like tends to fluctuate due to operating environment conditions, aging, etc., there is also the problem that the lubricating state tends to become unstable and complicated maintenance work is required on a regular basis. It was

Therefore, as a countermeasure against the above-mentioned problems,
In place of the caster washer 106, a technique of interposing a thrust needle roller bearing between the washers has also been developed. However, since the thrust needle roller bearing is thicker than the washer, the inclusion thereof causes an increase in caster height. For this reason, when applied to various pianos, the height from the floor surface to the keyboard cannot be kept substantially constant at all times, and the versatility is deteriorated. Therefore, this improved technique is still insufficient.

An object of the present invention is to provide a caster for a piano which solves the above-mentioned problems of the prior art all at once and suitably realizes high reliability and durability.

[0008]

In order to solve the above-mentioned problems, the structure according to claim 1 is fixed to a piano, and a bearing member for supporting a caster main shaft in a substantially gravity direction, the bearing member and the above-mentioned bearing member. A caster wheel receiving member that is rotatably connected around the caster spindle and that rotatably supports caster wheels in a direction substantially orthogonal to the caster spindle at a position distant from the caster spindle by a predetermined deviation distance in the radial direction. And an interposing between the caster wheel receiving member and the bearing member substantially coaxially with the caster main shaft, having a diameter of at least twice the predetermined deviation distance and made of a self-lubricating material. A gist of the present invention is a caster for a piano, which is provided with a member.

[0009]

According to the structure described in claim 1, the bearing member fixed to the piano supports the caster main shaft in a substantially gravity direction, and the caster wheel receiving member is located at a position separated by a predetermined deviation in the radial direction of the caster main shaft. When the caster wheel is rotatably supported in a direction substantially orthogonal to the caster main shaft, the interposing member made of a self-lubricating material and having a diameter that is at least twice the predetermined deviation distance is the caster wheel receiving member. And the bearing member so as to be interposed substantially coaxially with the caster main shaft.

That is, even if the caster wheel support position and the shaft center of the caster main shaft are separated from each other by a predetermined deviation distance, the caster wheel receiving member and the bearing member corresponding to the load acting position on the caster wheel are self-aligned. Since the interposition member made of the lubricous material is interposed, the bending moment acting on the caster wheel receiving member and the caster main shaft is alleviated.

Accordingly, the deformation of the caster main shaft and the caster wheel receiving member is suppressed while the smooth rotation of the bearing member and the caster wheel receiving member is maintained.

[0012]

The preferred embodiments of the present invention will now be described in detail with reference to the drawings.

First embodiment

A caster for a piano, which is a first embodiment of the present invention, will be described with reference to FIGS. 1 and 2. 1 is a side sectional view, and FIG. 2 is an exploded perspective view. As shown in these figures, a piano caster 1 includes a caster main bearing 2 fixed to a lower portion of a piano P, a caster main shaft 3 supported by the caster main bearing 2 in an axial direction substantially along a gravity direction, and the caster main shaft 3 An oil-free bearing 4, a thrust washer 5, which fits approximately concentrically with the caster wheel support 6, which fits the caster main shaft 3, and a caster reinforcement which restricts the movement of the caster wheel support 6 in the axial direction of the caster main shaft 3. It is composed of a washer 7, a caster axle 8 arranged on the caster wheel bridge 6 and caster wheels 9 rotatably fitted to the caster axle 8.

The caster main bearing 2 is composed of a flat plate portion 2A having a circular hole at its substantially center, and a pipe portion 2B welded and fixed to the flat plate portion 2A substantially concentrically with the circular hole in a substantially orthogonal direction. The caster main shaft 3 has a large-diameter portion 3A and a small-diameter portion 3B connected to the tip end in the axial direction, and the large-diameter portion 3A fits into the pipe portion 2B. The oil-free bearing 4 that fits on the caster main shaft 3 has a substantially disc shape with a circular hole 4A that is fitted in the large diameter portion 3A of the caster main shaft 3 at substantially the center. The upper surface 4B is a steel plate material, and the lower surface 4C is a self-lubricating surface. That is, a layer of porous bronze powder is provided on one surface of the steel plate material of the upper surface 4B as a back metal, and further,
A self-lubricating surface of the lower surface 4C is formed by forming a layer impregnated with a mixture of a tetrafluoroethylene resin, which is a self-lubricating material, and lead. As the self-lubricating material, for example, other non-ferrous metals, synthetic resins, or composite materials obtained by sintering these may be used. The thrust washer 5, which is in contact with the lower surface 4C of the oil-free bearing 4 and fits substantially concentrically with the caster main shaft 3, is made of bearing steel having a high hardness (hardness HRC50 or more), and the caster main shaft 3 is provided substantially at the center thereof. It has a substantially disc shape with a circular hole 5A that fits in the large diameter portion 3A. In addition, the upper surface 5B that comes into contact with the lower surface 4C that is the self-lubricating surface of the oil-free bearing 4 is polished and finished to have a smooth surface (surface roughness 3S or more).
By using a material having a high hardness and polishing a highly accurate smooth surface, the frictional force and the amount of wear generated between the oil-free bearing 4 and the thrust washer 5 are further reduced.

The caster wheel bridge 6 includes the oil-free bearings 4,
An upper surface 6A that holds the thrust washer 5 between the caster main bearing 2 and a fitting hole 6 that is bored substantially in the center of the upper surface 6A and that fits approximately concentrically with the caster main shaft 3.
B, a pair of side portions 6C supporting the caster wheels 9,
6D, and a pair of through holes 6E, 6F formed substantially coaxially on both sides 6C, 6D. The fitting hole 6
The small diameter portion 3B of the caster main shaft 3 is fitted to B.
The small diameter portion 3B is fitted in the fitting hole 7A of the caster reinforcing washer 7 arranged on the back surface side of the upper surface 6A.
In this way, caster spindle 3 with both ends crimped
This restricts the axial position of each of the above-mentioned constituent members. A caster axle 8 is inserted through through holes 6E and 6F formed in both side portions 6C and 6D of the caster wheel bridge 6, and caster wheels 9 are rotatably supported by the caster axle 8.

By the way, as shown in FIG. 1, the axis O of the caster main shaft 3 and the axis C of the caster axle 8 are separated by a predetermined deviation distance E1. On the other hand, the thrust washer 5 fitted substantially concentrically with the caster main shaft 3 has a radius R0 and the oil-free bearing 4 has a radius R1, both of which are set longer than the predetermined deviation distance E1. Here, since the load F acting on the piano caster 1 is directed toward the axis C of the caster axle 8, the caster main shaft 3 and the caster wheel bridge 6 have a bending moment in a direction of bending with respect to the axis O of the caster main shaft 3. To work. However, since both radii R0 and R1 are longer than the predetermined deviation distance E1 as described above, the peripheral portions of the oil-free bearing 4 and the thrust washer 5 extend beyond the line of action of the load F, so that the caster Bending moments acting on the main shaft 3 and the caster wheel bridge 6 are relaxed.

As described above, according to the first embodiment, between the caster main bearing 2 and the caster wheel bridge 6,
Since the oil-free bearing 4 having the radius R1 and the thrust washer 5 having the radius R0, which are substantially concentric with the caster spindle 3, and the thrust washer 5 having the radius R0, are interposed, the caster spindle 3 and the caster wheel bearing are applied when the piano caster 1 is loaded. The effect of the bending moment on 6 can be relaxed. This makes it possible to suppress the deformation of the caster main shaft 3 and the caster carriage 6 while maintaining the smooth rotation of the caster main bearing 2 and the caster carriage 6.
The reliability and durability of can be improved.

Further, the thickness of the oil-free bearing 4 and the thrust washer 5 is slightly thicker than the thickness of the conventional caster washer, and about half that of the thrust needle roller bearing. Therefore, the interposition of the oil-free bearing 4 and the thrust washer 5 does not cause the height of the piano caster 1 to increase. Therefore, even when it is applied to various pianos, the height from the floor surface to the keyboard can be kept substantially constant at all times, and high versatility is exhibited.

Further, since the lower surface 4C of the oil-free bearing 4 which is a self-lubricating surface is brought into contact with the upper surface 5B of the thrust washer 5 which is made by polishing the high hardness steel to a smooth surface,
When the caster main bearing 2 and the caster wheel bridge 6 rotate, the generation of frictional force and the amount of wear can be suppressed to a minimum even without lubrication. As a result, complicated maintenance work due to the environmental conditions of use of the caster for piano 1 and its secular change can be eliminated.

Second embodiment

Next, a second embodiment of the present invention will be described in detail with reference to FIGS. The difference between the second embodiment and the above-described first embodiment is that the thrust washer 5 is eliminated, and as an alternative, the circumferential grooves 16C, 16 are formed on the upper surface of the caster wheel carrier 16.
That is, D and 16E are formed.

The piano caster 11 of the second embodiment is
As shown in FIGS. 3 and 4, an oil-free bearing 14 is interposed between the caster main bearing 12 and the caster wheel bridge 16. Here, the radius R2 of the oil-free bearing 14 is set to be longer than a predetermined deviation distance E2 between the axis O of the caster main shaft 13 and the axis C of the caster axle 18.

The upper surface 14B and the lower surface 1 of the oil-free bearing 14
In the structure of 4C, the lower surface 14C is a self-lubricating surface as in the first embodiment described above. On the other hand, the lower surface 1 of the oil-free bearing 14
On the upper surface 16A of the caster carriage 16 that contacts the 4C,
A plurality of circumferential grooves 16C, 16 which are substantially concentric with the fitting hole 16B.
D and 16E are engraved. The other structure is the same as that of the above-described first embodiment, and the description thereof will be omitted.

According to the second embodiment having the above-mentioned structure, the following effects are produced in addition to the effects of the first embodiment. That is, it is a simple additional process that only engraves the circumferential grooves 16C, 16D, 16E on the upper surface 16A of the caster car carrier 16, and only the oil-free bearing 14 is provided between the caster main bearing 12 and the caster car carrier 16. Because of the structure with a small number of parts, the thickness of the caster washer of the prior art is about the same as that of the conventional caster washer, and it is less than half the thickness of the thrust needle roller bearing. Delivers even higher versatility without inviting an increase in height.

In the second embodiment, three circumferential grooves 16C, 16D and 16E are formed on the upper surface 16B of the caster wheel bridge 16.
Although the case of engraving individual pieces has been described, the number of circumferential grooves can be changed according to the depth thereof, and for example, several hundred pieces may be engraved by lathe processing. The shape is not limited to the concentric circles, but may be formed in a spiral shape, for example. With such a configuration, there is an advantage that continuous machining by a lathe becomes easy.

Although some embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and an upright piano or a grand piano is possible within the scope not departing from the technical idea thereof. Of course, it can be realized by various modes such as application to various keyboard musical instruments such as an automatic piano and an electronic piano.

[0028]

As described above in detail, according to the present invention, even if the caster wheel supporting position and the shaft center of the caster main shaft are separated from each other by a predetermined deviation distance, the caster vehicle corresponding to the load acting position on the caster wheel. Since the interposing member made of a self-lubricating material is interposed between the receiving member and the bearing member, the bending moment acting on the caster wheel receiving member and the caster main shaft is relaxed, so that the bearing member and the caster vehicle receiving member are It is possible to suppress the deformation of the caster main shaft and the caster wheel receiving member while maintaining the smooth rotation, and it is possible to dramatically improve the reliability and durability of the caster for a piano, which is an extremely excellent effect.

Further, since the interposition of the interposition member does not increase the caster height, the height from the floor surface to the keyboard can be kept substantially constant even when applied to various pianos, so that versatility is also enhanced. ..

Further, since the interposition member made of the self-lubricating material is used, the frictional force and the wear state can be suppressed to the minimum even when the bearing member and the caster wheel receiving member are rotated, without oiling. There is also an advantage that maintenance due to conditions and changes over time becomes unnecessary.

[Brief description of drawings]

FIG. 1 is a side sectional view of a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the first embodiment of the present invention.

FIG. 3 is a side sectional view of a second embodiment of the present invention.

FIG. 4 is a partially exploded perspective view of a second embodiment of the present invention.

FIG. 5 is a partial cross-sectional view showing a schematic configuration of a conventional technique.

[Explanation of symbols]

1 ... Caster, 2 ... Caster main bearing, 3 ... Caster main shaft, 4 ... Unlubricated bearing, 6 ... Caster wheel carrier, 9 ... Caster wheel shaft

Claims (1)

[Claims] 1. A bearing member fixed to a piano and supporting a caster spindle in a substantially gravitational direction, the bearing member and the bearing member being rotatably connected around the caster spindle, and a predetermined radial direction from the caster spindle. A caster wheel receiving member that rotatably supports caster wheels in a direction substantially orthogonal to the caster main axis at a position separated by a deviation distance, and between the caster wheel receiving member and the bearing member, substantially coaxial with the caster main axis. A caster for a piano, comprising: an interposing member made of a self-lubricating material and having a diameter that is at least twice the predetermined displacement distance.