The invention provides a caster including two wheels, a central frame member, and a mount member. The two wheels are mounted on the mount member. The caster has a hybrid bearing arrangement comprising both a rolling bearing and two slide bearings. The rolling bearing is located between the central frame member and the mount member and is configured to enable the caster to roll along a straight line with each of the two wheels rotating in a common direction about a first axis. Each of the two slide bearings is located between the mount member and a tread portion of a respective one of the two wheels. The slide bearings are configured to enable the two wheels to simultaneously rotate in opposite directions when the caster swivels about a second axis orthogonal to the first axis. In some embodiments, the caster is a hubless caster.

An anti-oscillation mechanism is provided for a caster wheel assembly of a ride-on vehicle. The anti-oscillating mechanism has a stop, a first cap, a second cap and a bias member. The stop is positioned within the frame of the ride-on vehicle. The first cap has a wall that abuts the stop. The second cap has a wall that abuts a stem of the caster wheel assembly. The bias member has a first end that engages the first cap, and a second end that engages the second cap. The bias member exerts a force on the second cap, which exerts a force on the stem to push the caster wheel assembly toward a ground to help prevent a wheel of the caster wheel assembly from lifting off the ground.

A caster hub is provided that includes a housing having a wall with internal and external surfaces and an axial bore defined by the wall. First and second bearings are disposed coaxially in the bore of the housing. Each bearing has a cylindrical inner race and a cylindrical outer race, with the races separated by rolling elements, and the races defining interior and exterior radial end faces of the bearings. A seat is disposed in the bore that is connected to the internal surface of the wall between the first and second bearings. The seat is engageable with the outer races of the bearings at the confronting interior end faces of the bearings. An inner spacer is disposed in the bore between the first and second bearings, the inner spacer being engageable with the inner races of the bearings at the confronting interior end faces of the bearings.

A coupling mechanism is provided for coupling a supporting element to a frame, and includes a base member and a C-shaped retainer. The frame includes a frame body and a leg member that has a leg body extending downwardly from the frame body to terminate at an enlarged leg end. The base member defines therein a recess for the enlarged leg end therein. The supporting element is coupled to a lower major surface of the base wall. The C-shaped retainer extends to be disposed about the leg body, and is configured to be detachably coupled to a surrounding wall of the base member for retaining the enlarged leg end in the recess.

A roller has a wheel, a wheel axle and a pin which protrudes upward from a housing of the roller. A sleeve sits on the pin and is spaced apart from the pin radially and axially upward by a damping material arranged between the sleeve and the pin, the damping material being arranged so that all axial and/or radial contact between the pin and the sleeve is prevented. Alternatively, an attachment damping part can be arranged on a pin of the roller in overlap with the pin, wherein the attachment damping part has an inner sleeve and an outer sleeve, the inner sleeve being spaced apart radially and axially upward by a damping material arranged between the inner sleeve and the outer sleeve. The damping material is arranged in such a way that all axial and/or radial contact between the inner sleeve and the outer sleeve is prevented.

An autonomous delivery vehicle having one or more caster wheels that may be held off the ground for a portion of the time that the autonomous delivery vehicle travels. Each caster wheel is mounted in a pivot with a centering mechanism to hold the caster wheels in a design orientation. The caster wheel in the design orientation maximizes the view of forward-looking sensors on the autonomous delivery vehicle. The centering mechanism uses a compression spring that drives a follower and swashshaft to apply a rotation force on the caster wheels. The rotational force urges the casters frame and wheels to return to a design position. The rotational force increases with the rotational difference between the caster rotational position and the design position.

A caster may include a shaft, a first elastic ring, a C-shaped ring, and a second elastic ring. The shaft has one end inserted and secured in a wheel, and a first rod is extended from the other end of the shaft, and a second rod protrudes from an end of the first rod. The diameter of the first rod is larger than that of the second rod, and an end of the second rod comprises a flexible portion. The shaft only needs to be processed to form the second rod and the flexible portion, and the first elastic ring and the second elastic ring which are identical are adapted to be formed through the same mold so as to save the manufacturing cost.