A foldable mechanism is applied to locking an infant carrier and includes first and second mounts and a locking member. The second mount is pivoted to the first mount and has first and second mating portions. The locking member is movably disposed between the first and second mounts and is movable along an axial direction of a rotating axis of the first and second mounts to lock and release rotation of the first mount. The locking member has a positioning portion and a locking portion. The first mount is locked at a first rotating position or a second rotating position via movement of the locking member. The positioning portion is engaged with the first mating portion to lock the first mount at the first rotating position. The locking portion is engaged with the second mating portion to lock the first mount at the second rotating position.

This rotation ring includes an inner ring with a first rolling element travel groove, an outer ring with a second rolling element travel groove that faces the first rolling element travel groove, and a plurality of rolling elements interposed between the first rolling element travel groove and the second rolling element travel groove. The plurality of rolling elements include a plurality of hard rolling elements disposed at intervals in the circumferential direction, and a plurality of soft rolling elements, at least three or more of which are disposed between the hard rolling elements adjacent to each other in the circumferential direction and which are lower in rigidity than the hard rolling elements.

The invention relates to a hub construction for a rotatable chair, whereby an uncomplicated and robust plain bearing design is provided. The plain bearing parts are manufactured of metal in such a way that the bearing surface on the underlying pin is softer than that of the overlying sleeve. A plain bearing according to the invention may be provided with an adjustable device for obtaining higher friction and thus an increased rotational resistance. In the upper part of the pin is arranged a horizontal bore, into which is fitted a plug shaped body, the ends of which extend outside the mouths of the bore in the bearing surface as an adjusting screw in the upper end of the pin is tightened against the middle section of the plug-shaped body.

This rotation ring includes an inner ring with a first rolling element travel groove, an outer ring with a second rolling element travel groove that faces the first rolling element travel groove, and a plurality of rolling elements interposed between the first rolling element travel groove and the second rolling element travel groove. The plurality of rolling elements include a plurality of hard rolling elements disposed at intervals in the circumferential direction, and a plurality of soft rolling elements, at least three or more of which are disposed between the hard rolling elements adjacent to each other in the circumferential direction and which are lower in rigidity than the hard rolling elements.

A connective unit to connect a roller with a seat's leg is disclosed. The connective unit comprises a supportive arm, a plastic cylindrical member, a pivotally connective member and a roller. The plastic cylindrical member may engage with a cylindrical hole provided in the supportive arm. The upper end of the pivotally connective member may engage with a first connective hole and the lower end of the pivotally connective member may engage with a second connective hole of the roller. Thanks to presence of the plastic cylindrical member, when the pivotally connective member rotates and causes the roller to rotate with it, the supportive arm doesn't have any contact with the pivotally connective member and thus noisy friction and impacts between them as in the prior art may be avoided. Therefore, the plastic cylindrical member is difficult to wear out as the pivotally connective member rotates.

A foldable mechanism is applied to locking an infant carrier and includes first and second mounts and a locking member. The second mount is pivoted to the first mount and has first and second mating portions. The locking member is movably disposed between the first and second mounts and is movable along an axial direction of a rotating axis of the first and second mounts to lock and release rotation of the first mount. The locking member has a positioning portion and a locking portion. The first mount is locked at a first rotating position or a second rotating position via movement of the locking member. The positioning portion is engaged with the first mating portion to lock the first mount at the first rotating position. The locking portion is engaged with the second mating portion to lock the first mount at the second rotating position.

A foldable mechanism is applied to locking an infant carrier and includes first and second mounts and a locking member. The second mount is pivoted to the first mount and has first and second mating portions. The locking member is movably disposed between the first and second mounts and is movable along an axial direction of a rotating axis of the first and second mounts to lock and release rotation of the first mount. The locking member has a positioning portion and a locking portion. The first mount is locked at a first rotating position or a second rotating position via movement of the locking member. The positioning portion is engaged with the first mating portion to lock the first mount at the first rotating position. The locking portion is engaged with the second mating portion to lock the first mount at the second rotating position.