Abstract: A fastener is formed monolithically, or as a one-piece structure, for example 100% plastic. The fastener includes a body having first and second portions on respective sides of a positioning wall or stop means. A first portion includes a plurality of compressible retention surfaces separated from adjacent retention surfaces by a corresponding conical structure and a cylindrical surface on the body. A second portion includes a plurality of resiliently flexible tongues spaced apart from each other. The tongues may be positioned on opposite sides of the body from each other, and/or at different axial positions along the body.

Abstract: A fastener is formed monolithically, or as a one-piece structure, for example 100% plastic. The fastener includes a body having first and second portions on respective sides of a positioning wall or stop means. A first portion includes a plurality of compressible retention surfaces separated from adjacent retention surfaces by a corresponding conical structure and a cylindrical surface on the body. A second portion includes a plurality of resiliently flexible tongues spaced apart from each other. The tongues may be positioned on opposite sides of the body from each other, and/or at different axial positions along the body.

Abstract: A wheel fixing device for a wheel assembly of a baby carriage including:a hollow shaft element at the extream end of the shaft;a rotatable seat rotatable with respect to the wheel assembly being rotatably connected with a lower part of the hollow shaft element; the rotatable seat having a pair of knobs;a hub body joining said rotatable seat and a pair of wheels of the wheel assembly; anda slidable housing comprising:a central recess for encompassing the hollow shaft element and being vertically slidable along the hollow shaft element;a central slot on both sides thereof;a hole on both sides thereof;a spring member at both sides thereof with two legs extending in the same direction and with one leg thereof retained in the hole of the slidable housing and the other leg retained in respective hole of the hollow shaft element for securing the slidable housing and the hollow shaft element together and for imparting a desirable resiliency therewithin such that the slidable housing has a tendency to move downwards w