Abstract: A wheel hub-and-bearing set assembly for a roller skate includes a spacer, a sleeve formed with a first flange at one end thereof and having an outer face, a pair of bearings mounted in a space between the spacer and the sleeve, a hub body sleeved on the sleeve, and a bearing cap disposed at the other end of the sleeve and formed with a second flange that cooperates with the first flange and the outer face to define a retaining space thereamong. The hub body is formed with a tongue that is fittingly received in the retaining space.

Abstract: An in-line skate includes a skate frame, front and rear wheels mounted rotatably on the skate frame, and a middle wheel assembly including at least two middle wheels, each of which is mounted rotatably on the skate frame between the front and rear wheels, is aligned with the front and rear wheels, and is rotatable about a rotation axis defined by the middle wheel. Each middle wheel further defines a wheel center and an inclined plane that passes through the wheel center and that is perpendicular to the rotation axis. The inclined plane is inclined relative to a vertical plane perpendicular to a ground plane by an acute angle. The front and rear wheels are inclined in the same direction as the middle wheels.

Abstract: A roller skate frame assembly includes a frame body with front and rear shoe-mounting plates that are formed with fastening holes, a pair of fastening units, and a bracket with front and rear mounting units, each of which has a first part secured to a shoe, and a second part formed with a fastening hole and secured to a respective one of the front and rear shoe-mounting plates through a respective one of the fastening units which extends through a pair of the fastening holes in the second part and the respective one of the front and rear shoe-mounting plates.

Abstract: A roller skate frame includes a wheel-mounting plate for mounting wheels thereon, a shoe-mounting plate projecting transversely from a top end of the wheel-mounting plate and disposed at one side of the wheel-mounting plate that is opposite to the wheels, a plurality of wheel-mounting protrusions projecting from the wheel-mounting plate, and a plurality of reinforcing ribs, each of which projects transversely from a bottom end of the wheel-mounting plate and interconnects two adjacent ones of the protrusions.