There is provided a spring-powered drive apparatus including a casing (102), an output shaft (103) mounted on the casing (102) in a relatively rotatable manner, a one way clutch (112) externally fitted on the output shaft (103) in the casing (102) and, a spiral spring (105, 107) housed in the casing and wound by turning of the output shaft (103) in the direction in which the one way clutch (112) transmits torque. Thus, there can be provided a compact spring-powered drive apparatus and a self-propelled caster that can be applied to a work cart or the like.

A wheel assembly includes a constant force mechanism and a wheel coupled to the constant force mechanism. The wheel is displaceable in at least one dimension, and the constant force mechanism imparts a substantially constant force on the wheel in the dimension. In one aspect, the wheel is displaceable in a first regime and a second regime. For a wheel displacement in the first regime, the constant force mechanism imparts a substantially constant force on the wheel, and for a wheel displacement in the second regime, the constant force mechanism imparts a variable force on the wheel. The variable force can be linear or non-linear to the magnitude of the displacement in the second regime and is equal to or greater than the substantially constant force.

A caster with an elastic member that absorbs impact forces during use. The elastic member can be placed between first and second portions pivotable with respect to each other about a pin. The elastic member can absorb impact forces between the first and second portions when in use. The elastic member can further include grooves that allow portions of the elastic member adjacent the grooves to flow into the grooves during impact, further absorbing impact forces.

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 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.

A castor assembly includes a base, a wheel unit and a rotation shaft. The wheel unit is located under the base and includes a pivot member, an elastic member biased and exposed between the base and the pivot member, and two rollers mounted on the pivot member. The rotation shaft is mounted between the base and the wheel unit and extends through the elastic member. The rotation shaft has a periphery provided with an operation slot. A positioning pin extends through the pivot member and is slidable in the operation slot of the rotation shaft. Thus, the elastic member is exposed outward so that the user clearly sees the elastic member and knows the shock-absorbing function provided by the elastic member.

A caster capable of removing a foreign substance includes a flange mounted to a carrier or a plate on which cargo is loaded so as to be spaced apart from a lower surface of the carrier or the plate, the flange having a plurality of coupling holes formed therein, a rotator rotatably mounted to a lower surface of the flange, lower support members mounted respectively to opposite sides of the rotator, each lower support member having a rotating shaft coupling hole formed in a lower portion thereof, a wheel located between the lower support members and supported by a rotating shaft, which penetrates the rotating shaft coupling hole, and a foreign substance removal device fixed to and supported by the rotating shaft, the foreign substance removal device serving to remove and collect the foreign substance attached to a surface of the wheel that is being rotated.

Bearing for at least one supporting roller of a carriage, which supporting roller is supported on at least one bearing surface, comprising at least one axle device which can be rotated about at least one rotational axis, at least one rocker which is connected to the axle device such that it is reliably driven, wherein, at an end which lies opposite the axle device, the rocker has at least one first connecting device for connecting the rocker to the supporting roller, at least one spring device which is arranged mechanically between the axle device and/or the rocker on one side and at least one holding device on the other side, wherein a force which forces the supporting roller onto the bearing surface can be built up on the axle device and the rocker by means of the spring device, and at least one damping device, by means of which a rotational movement of the axle device about the rotational axis can be damped, characterized in that the spring device and the damping device are configured in one piece at least in regions by way of at least one torsion spring element which is of rubber-elastic configuration at least in regions.

A patient support apparatus comprises a base supported by caster assemblies with each caster assembly comprising a stem, a caster wheel, and a caster wheel axle. A patient support surface is coupled to the base and is configured to receive a load. One or more load sensors are integrated with at least one of the stem, the caster wheel, or the caster wheel axle for measuring the load. One or more of the caster assemblies can be coupled to a steering motor, which controls orientation of the caster assembly. A controller can control the steering motors based on analyzing the measurements of the load sensor. The load sensors can produce measurements indicative of both vertical load and non-vertical load applied to the caster assembly. The controller can also analyze the measurements of the load sensor to determine the load received by the patient support surface by negating the non-vertical load.