초록 ▼

A main bag (3) stands independently and moves via free swiveling caster wheels 1 at four corners. A free swiveling caster wheel (1) is provided with a wheel (6), a yoke (7) connected to the wheel in a manner allowing the wheel to rotate, a radial bearing (8) with its outer ring (8B) connected to the

A main bag (3) stands independently and moves via free swiveling caster wheels 1 at four corners. A free swiveling caster wheel (1) is provided with a wheel (6), a yoke (7) connected to the wheel in a manner allowing the wheel to rotate, a radial bearing (8) with its outer ring (8B) connected to the yoke, a swivel shaft (9) connected to the inner ring (8A) of the radial bearing, and a mount (10) which holds the upper end of the swivel shaft fixed. The rotation axis (11) of the wheel is disposed with eccentricity with respect to the swivel axis (m), which is the center of rotation of the swivel shaft, allowing the yoke to swivel. The yoke and mount have a bend prevention gap (15) established between mutually opposing surfaces in close proximity. When a bending impact load acts on the swivel shaft, the yoke and mount press against each other at the bend prevention gap to support the bending impact force.

대표청구항 ▼

What is claimed is: 1. A bag comprising: a main bag; a plurality of free swiveling caster wheels that are free to swivel in any direction, the caster wheels being attached at four corners of a bottom surface of the main bag; and a handle provided so as to be extendable in an upward direction from t

What is claimed is: 1. A bag comprising: a main bag; a plurality of free swiveling caster wheels that are free to swivel in any direction, the caster wheels being attached at four corners of a bottom surface of the main bag; and a handle provided so as to be extendable in an upward direction from the main bag, wherein the main bag, standing independently on the free swiveling caster wheels at the four corners, can be moved freely in any direction via the handle, wherein each of the free swiveling caster wheels is provided with a wheel that is rotatable about a rotation axis, a yoke connected to the wheel so as to allow the wheel to rotate, a vertically oriented swivel shaft defining a swivel axis, and a mounting member holding an upper end of the swivel shaft, said mounting member being attached to a bottom surface of the main bag, wherein the rotation axis of the wheel is eccentrically disposed with respect to a central axis of the swivel shaft, and the yoke can swivel about the swivel shaft when the main bag is moved, wherein each of the free swiveling caster wheels is further provided with a radial bearing having an outer ring connected to the yoke, and an inner ring connected to the swivel shaft, wherein a first bend prevention gap is formed between an upper surface of the yoke and a lower surface of the mounting member, and the yoke and the mounting member are opposed in mutual proximity at a location that is separated in a radial direction from the swivel axis of the swivel shaft, wherein the mounting member has a projecting region that projects toward the inner ring, and a spacer is interposed between the projecting region and the inner ring so as to permit adjustment of a width of the first bend prevention gap, wherein the yoke defines a cylindrical cavity that is open at an upper end thereof and closed at a lower end thereof, the radial bearing being received and fixed in the cylindrical cavity, wherein the swivel shaft is inserted through a center of the radial bearing so that the radial bearing is pivotally connected to the swivel shaft, wherein an outer perimeter of the upper part of the yoke forms a cylindrical column, wherein the mounting member has a skirt that substantially covers the cylindrical column of the yoke, and a second bend prevention gap is formed between an inner surface of the skirt and the outer perimeter of the yoke, such that, when a bending impact force acts on the swivel shaft, due to an impact load applied to the main bag, the yoke and the mounting member apply pressure on each other at the first bend prevention gap and the second bend prevention gap to support the bending impact force, and wherein the radial bearing is a sealed bearing with seal material that closes off an open region between the inner ring and the outer ring. 2. A bag as recited in claim 1, wherein the handle is disposed at a central portion of the upper surface of the main bag. 3. A bag as recited in claim 1, wherein the handle is disposed at one side of the main bag and is movable from the side towards a position over a central portion of the upper surface of the main bag as it is pulled up. 4. A bag as recited in claim 1, wherein at least an outer peripheral region of each of the wheels is made of plastic which can deform or natural rubber, and a center region is formed of metal or hard plastic. 5. A bag as recited in claim 1, wherein the rotation axis of each of the wheels is spaced from the swivel axis of the swivel shaft by a distance of 10 mm to 20 mm. 6. A bag recited in claim 1, wherein an upper surface of the yoke defines a horizontal plane. 7. A bag as recited in claim 1, wherein the bend prevention gap has a width of 0.1 mm to 1 mm when the main bag is in an unloaded condition and is standing independently on a horizontal platform. 8. A bag as recited in claim 1, wherein the yoke is formed of metal or hard plastic. 9. A bag as recited in claim 1, wherein the mount is formed of metal or hard plastic. 10. A bag as recited in claim 1, wherein the slip ring is formed of a plastic sheet material. 11. A bag as recited in claim 1, wherein the yoke and the mount make direct contact and apply pressure on each other when a sufficient impact load is applied to the main bag. 12. A bag as recited in claim 1, wherein the spacer is made of resiliently deformable material. 13. A bag comprising: a main bag; a plurality of free swiveling caster wheels that are free to swivel in any direction, the caster wheels being attached at four corners of a bottom surface of the main bag; and a handle provided so as to be extendable in an upward direction from the main bag, wherein the main bag, standing independently on the free swiveling caster wheels at the four corners, can be moved freely in any direction via the handle; wherein each of the free swiveling caster wheels is provided with a wheel that is rotatable about a rotation axis, a yoke connected to the wheel so as to allow the wheel to rotate, a vertically oriented swivel shaft defining a swivel axis, and a mounting member holding an upper end of the swivel shaft, said mounting member being attached to a bottom surface of the main bag, wherein: the rotation axis of the wheel is eccentrically disposed with respect to a central axis of the swivel shaft, and the yoke can swivel about the swivel shaft when the main bag is moved; each of the free swiveling caster wheels is further provided with a radial bearing having an outer ring connected to the yoke, and an inner ring connected to the swivel shaft; a first bend prevention gap is formed between an upper surface of the yoke and a lower surface of the mounting member, and the yoke and the mounting member are opposed in mutual proximity at a location that is separated in a radial direction from the swivel axis of the swivel shaft; the yoke defines a cylindrical cavity that is open at an upper end thereof and closed at a lower end thereof to receive the radial bearing, and an outer perimeter of the upper part of the yoke forms a circular cylindrical column; the radial bearing is inserted into and fixed inside of the cylindrical cavity, and the radial bearing is pivotally connected at its center to the swivel shaft; the mounting member has a skirt that substantially covers the cylindrical column of the yoke, and a second bend prevention gap is formed between an inner surface of the skirt and the outer perimeter of the yoke, such that, when a bending impact force acts on the swivel shaft due to an impact load applied to the main bag, the yoke and the mounting member apply pressure on each other at the first bend prevention gap and the second bend prevention gap to support the bending impact force; and the radial bearing is a sealed bearing with seal material that closes off an open region between the inner ring and the outer ring.