A hollow caster structure includes a base, a caster body pivotally connected with the base, a first wheel unit mounted on the caster body, and a second wheel unit mounted on the caster body. Each of the first wheel unit and the second wheel unit forms a viewing space. Thus, the viewing space of each of the first wheel unit and the second wheel unit provides a visible effect. In addition, the hollow caster structure has a lighter weight by provision of the viewing space. Further, the parts of the hollow caster structure have different colors which are visible from the viewing space.

A wheel shock absorption structure and a child carrier having the wheel shock absorption structure, including a wheel shaft and a wheel seat connected with a frame, and a lower end of the wheel seat is rotatably connected with a wheel through the wheel shaft. Further including a shock absorber with an elastic structure, an upper end of the shock absorber is removably connected with an upper end of the wheel seat, and the shock absorber rotates synchronously along with the wheel seat; a lower end of the shock absorber is rotatably connected with the wheel shaft which is slidably connected with the lower end of the wheel seat. The shock absorber is driven by sliding of the wheel shaft to generate recoverable elastic deformation to provide damping and buffering. The bending deformation of the shock absorber ensures that the wheel shock absorption structure has a better shock absorbing effect.

A wheelchair can comprise: a frame comprising an upper portion and a lower portion that is coupled to the upper portion so that the upper portion is vertically adjustable with respect to the lower portion. A pair of drive wheels can be coupled to the frame. A plurality (e.g., a pair) of casters are coupled to the frame. Each caster can have a respective swivel axis. At least one caster of the plurality of casters can be configured to be locked to prevent swiveling about its respective swivel axis and unlocked to enable swiveling about its respective swivel axis.

State of the art track width adjustment mechanism fail to support track width adjustment while vehicle is in motion. They also require manual intervention, which causes inconvenience. The disclosure herein generally relates to wheel track adjustment, and, more particularly, to a changeable wheel track mechanism for track width adjustment (referred to as TWA mechanism). The TWA mechanism includes a steer and drive unit, a plurality of links, and a sliding unit. The TWA mechanism allows movement of a wheel in inward and outward directions, causing the track width adjustment. The track width is achieved by changing the wheel position to be at a wider position, or a narrower position, or any intermediate position. The TWA mechanism may be associated with any vehicle for which the track width adjustment is to be achieved.

A damper of the present invention includes: a damping portion that exerts a damping force by using a granular material at a time of extension and contraction; and an elastic portion that exerts an elastic force at the time of extension and contraction, wherein the damping portion is coupled to the elastic portion such that the damping force and the elastic force are exerted in parallel.

Self-propelled vehicles that include swiveling caster wheels and independent drive wheels are disclosed. The self-propelled vehicles are selectively steered in a caster wheel steering mode or a drive wheel steering mode. The vehicle includes a differential system that may include a differential valve that allows hydraulic fluid to be transferred between the left and right drive systems. The differential system may be operable during the caster wheel steering mode such as when the vehicle is driven for transport between sites.

A tube assembly for a wheelchair frame comprises a tubular member having at least a first portion and a second portion angled relative to the first portion, the first portion configured to be in a seating zone of the wheelchair frame. The second portion is configured to be in a bottom front zone of the wheelchair frame, the tubular member defining a surface concavity in its peripheral surface delimited by a peripheral step, the surface concavity located at a junction between the first portion and the second portion of the tubular member. An interface member has a peripheral contour shaped and sized for the interface member to be received in the surface concavity and contoured at least partially by the peripheral step.

A system of bracket assemblies for a wheelchair comprises a pair of bracket assemblies adapted to be connected to respective sides of a seat frame of the wheelchair. Each of the bracket assemblies has a base adapted to be secured to a seat frame member of the seat frame, an arm adapted to be secured to a backrest frame member of a backrest frame, and a pivot pivotally connecting the base to the arm for rotational movement of the arm relative to the base. One or more blocking mechanism blocks the rotational movement of the arm relative to the base in a use orientation of the backrest frame. A rod having opposed ends connected to the base of the pair of the bracket assemblies for spacing the bracket assemblies away from one another. A rear wheel unit is also provided.

A caster wheel assembly for an industrial vehicle comprising a lower housing connected to a wheel, an upper housing connectable to the industrial vehicle, and an inner alignment post disposed within the lower and upper housings. The upper housing is at least partially disposed within the lower housing. Rotation of the inner alignment post relative to the upper housing adjusts vertical displacement of the lower housing relative to the upper housing.

A caster wheel assembly for an industrial vehicle comprising a lower housing connected to a wheel, an upper housing connectable to the industrial vehicle, and an inner alignment post disposed within the lower and upper housings. The upper housing is at least partially disposed within the lower housing. Rotation of the inner alignment post relative to the upper housing adjusts vertical displacement of the lower housing relative to the upper housing.