JP4953858B2 - caster - Google Patents

Description

  The present invention relates to a caster that is attached to a main body such as a carriage used when conveying an article in a factory or the like.

  A caster is attached to the lower surface of a main body of a cart used for conveying articles in a factory or the like.

  In Patent Document 1, a fork is divided into an upper fork (housing) and a lower fork (strut arm), and a lower fork provided with a wheel on the lower side of the upper fork is pivotally supported so as to be rotatable in the vertical direction. In the shock absorbers in which the support part is offset from the vertical line of the axle and an elastic material (coil spring) is stretched between the upper surfaces of the upper and lower forks, the lower part of the elastic material is fixed to the upper plate of the lower fork. Further, it is disclosed that the upper plate of the lower fork is engaged with the top plate through the balance pin, and the upper portion of the elastic member is engaged with the top plate through the thrust bearing.

  In Patent Document 2, the fork is divided into an upper fork (housing) and a lower fork (strut arm), and a lower fork provided with a wheel on the lower side of the upper fork is pivotally supported so as to be rotatable in the vertical direction. In the buffer caster in which the support part is shifted from the vertical line of the axle, and an elastic material (coil spring) urging vertically between the upper fork and the lower fork is stretched, the lower part of the elastic material is the lower fork The upper surface of the elastic material is engaged with a tapered tapered protrusion fixed upward, and the upper part of the elastic member receives a spring receiver that can be rotated via a bearing receiver of the upper fork and a thrust bearing. A surface is disclosed which is engaged with a tapered tapered protrusion attached downward to the spring receiver.

  In Patent Document 3, a spring (coil spring) provided at the lower portion of the carriage to elastically support the carriage, a spring receiving member (strut arm) provided at the lower end of the spring, and a horizontal axis with respect to the spring receiving member A balance member that is pivotably connected around the wheel, an axle that rotatably passes through the balance member, and wheels that are attached to both ends of the axle. A caster is disclosed in which the connecting portion is positioned below the axle.

  In Patent Document 4, a wheel that is rotatably supported by an axle, a support structure that supports a main body mounted on a caster, one end is connected to the axle, and the other end is connected to the support structure and the rotation shaft. The swing arm has a swing range in which the rotation axis is a posture in which the rotation shaft is positioned in the traveling direction of the axle from a posture in which the rotation shaft is located in the vertical downward direction of the axle. It is disclosed that the rotation including at least a part is possible, and that the main body is lifted by the rotation of the swing range of the swing arm.

Patent Document 5 discloses that a caster comprising a rotating body provided rotatably at the lower portion of a vehicle body, an arm coupled obliquely downward to the rotating body, and a wheel rotatably supported at the lower portion of the arm. The body is composed of a rotating shaft vertically suspended from the vehicle body, and a cylindrical bearing that is formed integrally with a lower portion of the rotating shaft and forms a horizontal axis perpendicular to the axis of the rotating shaft, An elastic cylindrical bush is fitted in the center of the bearing in a direction perpendicular to the rotation axis, and a pin provided integrally with the upper part of the arm is fitted in the center of the bush, and the upper part of the arm is connected via the pin. It is disclosed that a low-friction sliding member is interposed between the side surface of the bearing and the inner peripheral surface of the arm while being coupled along the side surface of the bearing.
Japanese Patent No. 3095993 Japanese Patent No. 3689482 JP-A-61-241201 JP 2006-27520 A Japanese Patent No. 3705931

  By the way, the caster is provided with a housing so that the main shaft portion penetrates the mounting plate having the plate main body and the main shaft portion extending downward therefrom, and also prevents the main shaft portion from slipping across the housing with the plate main body. An outer fitting member that is externally fitted and fixed to the main shaft portion is provided, and a plurality of first rigid spheres are interposed between the plate main body and the housing between the housing and the outer fitting member so as to surround the main shaft portion. There is also a structure in which a plurality of second hard spheres are respectively disposed so as to surround the main shaft portion. Such a caster is provided with a strut arm provided in a housing so as to be rotatable within a predetermined angle range, a coil spring is interposed between the housing and the strut arm in a compressed state, and a wheel that is rotatable on the strut arm. The housing, the strut arm, the coil spring, and the wheel are rotatably provided around the main shaft portion with respect to the mounting plate and the external fitting member via the first and second rigid balls. It has a structure.

  An object of this invention is to attain dust prevention to the part in which the some 2nd hard sphere is provided by simple structure.

The caster according to the present invention that achieves the above object is
An attachment plate having a plate body and a main shaft portion extending downward from the plate body;
A housing provided so that the main shaft portion penetrates the mounting plate;
An outer fitting member that is provided so as to be prevented from coming off from the main shaft portion with the housing sandwiched between the plate body, and is externally fixed to the main shaft portion;
A plurality of first rigid spheres sandwiched between the plate body and the housing and disposed so as to surround the main shaft portion;
A plurality of second rigid spheres sandwiched between the housing and the outer fitting member and disposed so as to surround the main shaft portion;
A cap provided to cover the outer fitting member on the lower side of the housing and to have its entire upper end abutting against the housing;
A strut that is provided in the housing so as to be rotatable in a predetermined angle range with a horizontal axis at a position shifted laterally from below the main shaft portion as a rotation axis, and having a main shaft facing portion positioned below the main shaft portion Arm,
A coil spring interposed between the cap and the main shaft facing portion of the strut arm in a compressed state;
A wheel provided on the strut arm so as to be rotatable about a horizontal axis parallel to the rotation axis;
With
The housing, the cap, the strut arm, the coil spring, and the wheel are rotatably provided around the main shaft portion with respect to the mounting plate and the external fitting member via the first and second rigid balls. It is characterized by being.

  According to the above configuration, the cap covers the outer fitting member on the lower side of the housing and the entire periphery thereof is in contact with the housing, and the cap does not have a specific fixing means, and the elasticity of the coil spring allows the housing to be Therefore, the portion where the plurality of second hard spheres are provided is cut off from the outside by such a simple configuration, so that the portion can be protected from dust.

  In the present invention, the cap may be provided with spring positioning means for preventing fluctuations in the contact position of the coil spring.

  According to the above configuration, since the spring positioning means prevents fluctuations in the contact position of the coil spring, it is possible to suppress a change with time in the damping characteristic due to the coil spring.

  In the present invention, a friction damper may be interposed between the strut arms at the position where the strut arms are attached to the housing.

  According to the above configuration, the impact when passing through a large height difference is attenuated early by the friction between the friction damper and the housing and the friction between the friction damper and the strut arm in addition to the coil spring. Therefore, it is possible to suppress an excessive amplitude from being given to the conveyed object or the like.

  In the present invention, a cover material may be interposed so as to surround the plurality of first hard spheres and be sandwiched between the plate body and the housing.

  According to said structure, since a cover material also shares a load in addition to a 1st rigid sphere, abrasion of a 1st rigid sphere is suppressed and lifetime can be achieved. In addition, the portion where the plurality of first hard spheres are provided by the cover material is blocked from the outside, whereby the portion can be protected from dust.

  According to the present invention, the cap covers the outer fitting member on the lower side of the housing and the entire periphery thereof is in contact with the housing, and the cap does not have an inherent fixing means, and the elasticity of the coil spring allows the housing to be Since it is pressure-fixed, it is possible to achieve dust prevention to the portion where the plurality of second hard balls are provided by such a simple configuration.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1-6 shows the caster C which concerns on this embodiment. In the following description, the upper and lower sides of the drawing are the upper and lower sides of the caster C, and the left and right sides are the front and rear of the caster C.

  The caster C is attached to a main body such as a cart used when conveying an article in a factory, an office or the like.

  The caster C includes an attachment plate 10 that is directly attached to the lower surface of a main body such as a carriage. The mounting plate 10 is made of a metal member, and includes a plate body 11 and a main shaft portion 12 extending downward from the plate body 11.

  The plate body 11 is formed in a substantially square shape, and mounting holes 11a for inserting mounting bolts are drilled in the four corners. Further, the plate body 11 is formed with a projecting portion 11b projecting downward in the shape of a truncated cone, and a circular hole is formed at the center of the top surface of the projecting portion 11b, and the lower portion so as to surround the circular hole. A circumferential groove having a circular arc cross section is formed.

  The main shaft portion 12 is formed in a cylindrical shape, and has a first portion 12a having the same outer diameter as the circular hole of the plate body 11 from the upper side to the lower side, and the outer diameter is discontinuously following the first portion 12a. The second portion 12b, which is enlarged and maintained at a constant outer diameter, and the third portion 12c, the outer diameter of which decreases in a tapered shape as it goes to the tip, are sequentially formed following the second portion 12b. The third portion 12c is formed thicker than the first and second portions 12a and 12b. The main shaft portion 12 has a proximal end inserted through a circular hole of the plate body 11 and is fixed by caulking on the upper side thereof.

  The caster C includes a housing 20 provided on the lower side of the mounting plate 10.

  The housing 20 is made of a metal member, and has an upper plate portion 21 having long sides in the front-rear direction, and a side plate formed so as to extend downward continuously from both long sides and rear short sides of the upper plate portion 21. Part 22.

  A circular hole is formed at the center of the rear side portion of the upper plate portion 21, and the housing 20 is provided so that the main shaft portion 12 of the mounting plate 10 passes through the circular hole.

  On the upper surface of the upper plate portion 21, a circumferential groove having an arc-shaped cross section opened upward so as to surround the circular hole is formed. The circumferential groove is positioned so as to face the circumferential groove of the plate body 11 of the mounting plate 10, and the radius of the groove itself and the radius of curvature of the cross-section arc are the same as those of the plate body 11. . A plurality of first rigid balls 23 (steel balls) are sandwiched between the circumferential grooves facing each other of the plate body 11 and the upper plate portion 21 via grease and disposed along the circumferential direction of the grooves. ing. The plurality of first hard spheres 23 are disposed so as to surround the main shaft portion 12, and accordingly, a ball bearing structure that allows the mounting plate 10 and the housing 20 to rotate relative to each other with the main shaft portion 12 as the rotation center is configured as described above. It is configured. In addition, between the plate main body 11 and the upper plate portion 21, a ring disk-shaped cover member 24 formed so as to envelop the plurality of first hard spheres 23 is interposed. The cover material 24 is formed of, for example, nylon resin that is excellent in performance such as mechanical strength and sag resistance, and is fixed to either the plate body 11 or the upper plate portion 21. It may be non-fixed.

  On the lower surface of the upper plate portion 21, a circumferential groove having an arc-shaped cross section opened downward is formed so as to surround the circular hole. The circumferential groove is formed so that both the radius of the groove itself and the radius of curvature of the cross-sectional arc are smaller than those of the upper surface.

  A portion of the side plate portion 22 that is continuous with both of the long sides of the upper plate portion 21 is formed in a shape that is tapered forward and downward, and a support hole 22a is formed at the tip portion.

  The caster C includes an outer fitting member 30 provided on the lower side of the housing 20.

  The outer fitting member 30 is composed of a metal member, and a cylindrical member upper part 30a and a donut board-like member lower part 30b are coaxially and integrally formed. The outer fitting member 30 has an inner diameter that is substantially the same as the outer diameter of the first portion 12a of the main shaft portion 12 of the mounting plate 10, and a member length that is the same as that of the first portion 12a. 30 a is inserted through the circular hole of the housing 20 in a non-contact manner, and is provided so as to be fitted and fixed to the first portion 12 a of the main shaft portion 12 as a whole.

  On the upper surface of the member lower part 30b, a circumferential groove having an arc-shaped cross section opened upward is formed so as to surround the member upper part 30a. The circumferential groove is positioned so as to face the circumferential groove on the lower surface of the upper plate portion 21, and the radius of the groove itself and the radius of curvature of the cross-sectional arc are the same as those of the upper plate portion 21. . A plurality of second rigid spheres 31 (steel balls) are sandwiched between the circumferential grooves facing each other by the upper plate portion 21 and the member lower portion 30b and disposed along the circumferential direction of the groove. ing. The plurality of second hard spheres 31 are disposed so as to surround the main shaft portion 12, and accordingly, the ball bearing structure that allows the housing 20 and the external fitting member 30 to rotate relative to each other with the main shaft portion 12 as the rotation center. Is configured.

  The caster C includes a cap 40 provided on the lower side of the outer fitting member 30.

  The cap 40 is formed of a resin member made of, for example, nylon resin having a bottomed cylindrical shape opened upward. A circular hole having an inner diameter slightly larger than the outer diameter of the second portion 12 b of the main shaft portion 12 of the mounting plate 10 is formed at the center of the bottom portion of the cap 40. The cap 40 has a circular hole at the bottom portion of the main shaft portion 12. The main shaft portion 12 is inserted so as to be positioned corresponding to the second portion 12b, and the outer fitting member 30 is covered in a non-contact manner, and the entire upper end is not in contact with the lower surface of the upper plate portion 21 of the housing 20. It is provided by bonding. On the lower surface side of the cap 40, a ridge extending along the outer peripheral edge is formed, thereby forming a shallow concave portion 40a that opens downward.

  The caster C includes a strut arm 50 provided below the cap 40.

  The strut arm 50 includes a rectangular plate-shaped main shaft facing portion 51 positioned below the main shaft portion 12 and a wheel mounting portion 52 formed so as to continuously extend downward on both sides of the main shaft facing portion 51. And having.

  Each wheel mounting portion 52 is formed in a plate shape tapered toward the rear and obliquely downward, and an axle hole 52b is formed at the tip portion. A tongue piece protruding upward is formed at the front end of each wheel mounting portion 52, and a support shaft hole 52c is formed in the tongue piece. The tongue piece of one wheel mounting portion 52 is configured with a stopper portion 52a formed by bending inward continuously from the front edge.

  The strut arm 50 includes a fulcrum bolt 53, a support shaft hole 52c of one wheel mounting portion 52, a donut disk-shaped friction damper 54, one support shaft hole 22a of the side plate portion 22 of the housing 20, and a metal cylindrical collar 55. The other support shaft hole 22 a of the side plate portion 22 of the housing 20, the doughnut-like friction damper 54, and the support shaft hole 52 c of the other wheel mounting portion 52 are passed through in this order, and the bolt head is engaged with the one wheel mounting portion 52. At the same time, a nut 56 is tightened to the other wheel mounting portion 52 so that a gap is not formed between them, and a horizontal axis that is pivotally supported with respect to the housing 20 and on which the support bolt 53 extends is a rotation axis. It is provided so as to be rotatable. The rotatable angle range of the strut arm 50 is a predetermined angle range (for example, 0 to 8 °) in a range from a position where the upper side of the stopper portion 52 a contacts the housing 20 to a position where the upper side of the stopper portion 52 a contacts the housing 20. is there. The friction damper 54 is made of, for example, polyacetal resin.

  A rubber damper 57 is provided on the upper surface side of the main shaft facing portion 51. The rubber damper 57 includes a rectangular sheet portion 57a having substantially the same outer shape as that of the main shaft facing portion 51, and a columnar portion 57b integrally formed thereon. The rubber damper 57 is made of, for example, fluorine rubber.

  Between the cap 40 and the main shaft opposing portion 51 of the strut arm 50, a metal coil spring 60 in a compressed state is interposed. The upper part of the coil spring 60 is fitted in the recess 40a on the lower surface side of the cap 40, and the upper end contacts the bottom, thereby pushing the entire upper end of the cap 40 against the lower surface of the upper plate part 21 of the housing 20. Further, the lower part is provided on the cylindrical part 57b of the rubber damper 57 in an outer fitting shape, and the lower end is in contact with the rectangular sheet part 57a. As a result, in the normal state, the strut arm 50 is positioned at a position where the upper side of the stopper portion 52a contacts the housing 20, and a clearance of several mm is provided between the main shaft portion 12 of the mounting plate 10 and the rubber damper 57. It is formed.

  The caster C includes a hard urethane resin wheel 70 attached to the strut arm 50.

  In the wheel 70, an axle bolt 71 is passed through an axle hole 52 b of one wheel attachment portion 52 of the strut arm 50, a wheel 70, an axle hole 52 b of the other wheel attachment portion 52, and a washer 72 in this order. A bolt head is engaged with 52 and a nut 73 is tightened into the other wheel mounting portion 52, so that the horizontal axis on which the axle bolt 71 extends is rotatable with respect to the strut arm 50.

  In this caster C, the housing 20, the cap 40, the strut arm 50, the coil spring 60, and the wheel 70 are connected to the mounting plate 10 and the external fitting member 30 via the first and second rigid balls 23 and 31. The strut arm 50 is provided so as to be rotatable about 12 and the horizontal axis at a position diagonally forward and downward of the main shaft portion 12 with respect to the housing 20 shifted from the lower side of the main shaft portion 12 to the side. Further, the wheel 70 is provided so as to be rotatable in an angular range. Further, the wheel 70 is obliquely rearward and downward with respect to the strut arm 50 from the lower side of the main shaft portion 12 to the side. In this position, it is rotatably supported with a horizontal axis parallel to the rotation axis of the strut arm 50 as a rotation axis.

  According to the caster C having the above configuration, the cap 40 covers the outer fitting member 30 on the lower side of the housing 20 and the entire periphery thereof is in contact with the housing 20, and the cap 40 has a specific fixing means. Since the coil spring 60 is elastically pressed and fixed to the housing 20, the portion where the plurality of second rigid balls 31 are provided is cut off from the outside by such a simple configuration, thereby preventing dust from being applied to the portion. Can be planned.

  In addition, since the concave portion 40a on the lower surface side of the cap 40 prevents fluctuations in the contact position of the coil spring 60, it is possible to suppress a change with time in the damping characteristic due to the coil spring 60. That is, the concave portion 40a of the cap 40 constitutes a spring positioning means that prevents the contact position of the coil spring 60 from changing. The spring positioning means is not limited to this, and may have other configurations such as a convex portion.

  In addition, the caster C absorbs the impact when passing the height difference when the article is transported, etc., as the strut arm 50 rotates with respect to the housing 20 and the coil spring 60 expands and contracts. However, when passing a large height difference, in addition to absorbing the impact at that time by the coil spring 60, the friction between the friction damper 54 and the housing 20 and between the friction damper 54 and the strut arm 50 Since it is attenuated and absorbed at an early stage due to the friction, it is possible to prevent an excessive amplitude from being given to a conveyed object or the like.

  In addition to the first rigid sphere 23, the cover member 24 also shares the load, so that the wear of the first rigid sphere 23 can be suppressed and the life can be extended. The portion where the first hard sphere 23 is provided is blocked from the outside, so that the portion can be protected from dust.

  Further, when the strut arm 50 rotates excessively, the impact can be absorbed by the main shaft portion 12 of the mounting plate 10 coming into contact with the rubber damper 57. In this embodiment, the rubber damper 57 is provided on the upper surface side of the main shaft facing portion 51 of the strut arm 50. However, the present invention is not particularly limited to this, and as shown in FIG. The small-sized absorber 80 may be provided between the main shaft opposing portion 51 and the main shaft opposing portion 51.

  INDUSTRIAL APPLICATION This invention is useful about the caster provided in the trolley | bogie etc. which are used when conveying goods in a factory and others.

It is a side view which shows the cross section partially of the caster which concerns on embodiment. It is a top view of the caster concerning an embodiment. It is a bottom view of the caster concerning an embodiment. It is a rear view of the caster concerning an embodiment. It is a side view which shows the principal part cross section of the caster which concerns on embodiment. It is a disassembled side view which shows the cross section partially of the caster which concerns on embodiment. It is a side view which shows the principal part cross section of the modification of the caster which concerns on embodiment.

Explanation of symbols

C caster 10 mounting plate 11 plate main body 12 main shaft portion 20 housing 23 first rigid sphere 24 cover member 30 outer fitting member 31 second rigid sphere 40 cap 40a recess (spring positioning means)
50 Strut arm 51 Main shaft facing portion 54 Friction damper 60 Coil spring 70 Wheel

Claims (4)

An attachment plate having a plate body and a main shaft portion extending downward from the plate body;
A housing provided so that the main shaft portion penetrates the mounting plate;
An outer fitting member that is provided so as to be prevented from coming off from the main shaft portion with the housing sandwiched between the plate body, and is externally fixed to the main shaft portion;
A plurality of first rigid spheres sandwiched between the plate body and the housing and disposed so as to surround the main shaft portion;
A plurality of second rigid spheres sandwiched between the housing and the outer fitting member and disposed so as to surround the main shaft portion;
A cap provided to cover the outer fitting member on the lower side of the housing and to have its entire upper end abutting against the housing;
A strut that is provided in the housing so as to be rotatable in a predetermined angle range with a horizontal axis at a position shifted laterally from below the main shaft portion as a rotation axis, and having a main shaft facing portion positioned below the main shaft portion Arm,
A coil spring interposed between the cap and the main shaft facing portion of the strut arm in a compressed state;
A wheel provided on the strut arm so as to be rotatable about a horizontal axis parallel to the rotation axis;
With
The housing, the cap, the strut arm, the coil spring, and the wheel are rotatably provided around the main shaft portion with respect to the mounting plate and the external fitting member via the first and second rigid balls. Casters that are characterized by being. The caster according to claim 1,
The caster according to claim 1, wherein the cap is provided with spring positioning means for preventing fluctuation of the contact position of the coil spring. The caster according to claim 1 or 2,
A caster, wherein a friction damper is interposed between the strut arms at a position where the strut arms are attached to the housing. The caster according to any one of claims 1 to 3,
A caster characterized in that a cover material is interposed so as to surround the plurality of first hard spheres and be sandwiched between the plate body and the housing.

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