Abstract: An improved rotatable joint of the kind disclosed in U.S. Pat. No. 5,381,570 for foldable tubular playpen frames having a step in the tooth of a recessed sprocket portion in which a connecting gear rests. In order to unlock the joint one must move the gear axially inwardly with a pushbutton as well as relieve the stresses on the joint by lifting up the tubular bars connected to the joint so that the gear may slip off the step. In this way an additional factor of safety is built-in in order to unlock the joint, and accidental release is reduced.

Abstract: A modular wheel assembly for use with apparatus having a weight-bearing frame, such as a baby stroller, includes a mounting unit consisting of a cylindrical tubular member having an open upper end and a closed lower end wall. The tubular member is dimensioned to receive the lower end of a tubular frame member of the apparatus. A wheel supporting unit includes a cylindrical sleeve portion dimensioned to receive the tubular member of the mounting unit in close tolerance, freely rotating fashion. The sleeve portion and mounting unit are dimensioned so that the weight supported by the frame member is transferred through the bearing flange of the mounting unit to the cylindrical sleeve portion of the wheel supporting unit. An axle tube extends perpendicularly through lower end portions of the web members to be supported thereby. The axle tube is adapted to receive an axle therethrough, with a pair of wheels secured to opposed ends of the axle.

Abstract: An adjustable height mechanism for use in devices employing a collapsible scissors frame supporting an object is disclosed having a pair of pawls secured to the sliding leg of the scissors frame and slidably mounted onto a pair of guide rails. A central channel is positioned between the guide rails and receives a guide member extending from the leg to provide additional tracking and lateral stability during movement of the leg. A pair of spring biased, pivoting ratchet arms are mounted to the supported object and include a series of ratchet stops and a finger grip. The ratchet arms engage the pawls to restrict movement of the leg of the scissors frame in one direction while allowing ratcheting free movement in the opposite direction. The finger grips can be used by the user to squeeze the free ends of the arms together and release the ratcheting engagement with the pawls to provide height adjustment of the object supported by the scissors frame.