Abstract: A hospital bed includes a carrier frame, a driven wheel unit disposed below the frame, a motor unit, a drive wheel unit disposed below the frame and coupled operably to the motor unit in such a manner that actuation of the motor unit results in rotation of the drive wheel unit. A lifting-and-lowering device interconnects the frame and the drive wheel unit for lowering and lifting the drive wheel unit with respect to the driven wheel unit between an upper position, in which, the drive wheel unit is disposed at an elevation above the driven wheel unit, and a lower position, in which lower surfaces of the driven and drive wheel units are flush with each other.

Abstract: A speed reduction system includes a rotating source, a first ring gear, a first holding seat, a first gear set disposed on the first holding seat, meshed with the first ring gear and coupled to an output shaft of the rotating source, a second ring gear juxtaposed to the first ring gear, a second holding seat, and a second gear set disposed on the second holding seat, meshed with the second ring gear and coupled to a central axle of the first holding seat. Activation of the rotating source results in synchronous rotation of the first gear set and the first holding seat, which, in turn, results in relative rotation between the second ring gear and second holding seat so as to provide a torque, by virtue of interconnection between the central axle of the first holding seat and the second gear set.

Abstract: A hospital bed includes a carrier frame, a driven wheel unit disposed below the frame, a motor unit, a drive wheel unit disposed below the frame and coupled operably to the motor unit in such a manner that actuation of the motor unit results in rotation of the drive wheel unit. A lifting-and-lowering device interconnects the frame and the drive wheel unit for lowering and lifting the drive wheel unit with respect to the driven wheel unit between an upper position, in which, the drive wheel unit is disposed at an elevation above the driven wheel unit, and a lower position, in which lower surfaces of the driven and drive wheel units are flush with each other.

Abstract: A wheel assembly includes a driven member and a rotating member sleeved rotatably on an axle. The driven member includes a primary part, and a secondary part that is sleeved rotatably around the primary part, and that cooperates with the primary part to form a tongue-receiving space therebetween. A tongue-defining wall having opposite large and narrow wall sections confines the tongue-receiving space. An engagement tongue is disposed movably within the tongue-receiving space. An urging member urges the tongue to engage the narrow wall section of the tongue-confining wall, thereby coupling the primary and secondary parts. The rotating member has a pushing arm parallel to the axle, and extends into the narrow wall section in such a manner so as to be disposed at one side of the engagement tongue opposite to the urging member.