Abstract: An adjustable-height bicycle seat post assembly comprises a hollow seat post for supporting a bicycle seat slidably on plastic guides or shims inside a hollow tube. The hollow tube clamps into the frame of a bicycle. A mainspring forces the post upward, but a locking mechanism interconnects the post with the tube in various fixed positions relative to the tube. The locking mechanism includes a housing, which supports a plunger for reciprocating movement into and out of engagement with holes on the post. The locking mechanism is affixed to the outside of the tube to bear shearing forces on the plunger. An endcap on the locking mechanism and a topcap on the tube protect the assembly from foreign debris. The locking mechanism may be manipulated remotely using a magnetic switch assembly or manually using a mechanical assembly.

Abstract: An adjustable-height bicycle seat post assembly comprises a hollow seat post for supporting a bicycle seat slidably on plastic guides or shims inside a hollow tube. The hollow tube clamps into the frame of a bicycle. A mainspring forces the post upward, but a locking mechanism interconnects the post with the tube in various fixed positions relative to the tube. The locking mechanism includes a housing, which supports a plunger for reciprocating movement into and out of engagement with holes on the post. The locking mechanism is affixed to the outside of the tube to bear shearing forces on the plunger. An endcap on the locking mechanism and a topcap on the tube protect the assembly from foreign debris. The locking mechanism may be manipulated remotely using a magnetic switch assembly or manually using a mechanical assembly.