Suspension skock absorber for bicycles

A suspension assembly for a steerable wheel, comprising

• an elongated outer tube,
• an elongated inner tube having a portion adjacent its upper end telescopically and coaxially received within a portion adjacent the lower end of the outer tube for sliding movement axially of the outer tube in guided relation,
• a shock-absorbing mechanism received within and coupled between the inner and outer tubes and including an upper cap connected to the outer tube above the upper end of the inner tube, a through-tube coupled to the outer tube axially and rotatable relative to the outer tube, concentrically positioned in an upper portion of the outer tube, and having its lower end extending into an upper portion of the inner tube, a preload shaft received in the through-tube and having at its lower end a preload piston located below the lower end of the through-tube, means for adjusting the axial position of the preload shaft relative to the through-tube, and at least one compression spring disposed in the inner tube and engaged under a preload between the inner tube and the preload piston;
• and
• a hydraulic damper unit connected between the inner tube and the outer tube and including a cylinder member received coaxially within an upper portion of the inner tube, affixed to the inner tube and surrounding a portion of the through-tube, a piston member having an annular piston body received within the cylinder member and a tubular piston rod extending upwardly and joined at its upper end to the upper cap and telescopically receiving a portion of the through-tube, the outer diameter of the piston rod and the outer diameter of the portion of the through-tube below the piston body and within the cylinder member being equal, upper and lower end caps affixed to the upper and lower ends of the cylinder member and sealed in sliding relation to the piston rod and the through-tube, respectively, the cylinder member, end caps and portions of the piston rod and through-tube defining an annular closed chamber, a hydraulic liquid contained in the chamber, and bypass means for permitting restricted flow of the hydraulic liquid between portions of the chamber on opposite sides of the piston upon movement of the piston through the chamber in response to axial acceleration of the outer tube relative to the inner tube.