A wheeled hospital bed is removably connectible to a drive unit. The bed comprises a plurality of articulated frame sections, a plurality of driven shafts, a linkage interconnecting the driven shafts and the frame sections for articulating the latter in response to rotation of the driven shafts, and a first guide structure. The drive unit includes a plurality of motors and drive shafts, and a second guide structure arranged to interact with the first guide structure of the bed when the bed is merged with the drive unit in order to orient the bed and drive units such that the drive and driven shafts are mutually aligned. The drive and driven shafts include a self-coupling mechanism for establishing a drive connection therebetween when in a merged condition. The drive unit may be anchored to the floor, or may be supported solely by the bed. In the former case, the bed can be rotatable about a vertical axis relative to the drive unit while maintaining connection therewith. The drive unit carries a pair of side guards which are arranged to straddle the bed. The side guards are connectible to an articulatable section of the bed so as to be movable therewith.