Simple bicycle lock structure

A simple bicycle lock structure comprising:

• a shackle being a U-shaped member to be mounted on a rear fork of a bicycle, and opening ends of said shackle including a rotary section and a locking section respectively;
• said rotary section being a 90.degree. elbow-shaped member to be inserted in a hole of a movable sleeve in an outer-cylinder-positioning assembly fitted in an outer cylinder;
• said locking section of said shackle facing a round hole in an upper side of said outer cylinder;
• said shackle and said locking section being not on a same plane, but being connected together by means of an inner portion;
• and said locking section including a bevel facet and a locking groove to facilitate said locking section to enter a locking assembly through said round hole on the upper side of said outer cylinder;
• said outer cylinder including said outer-cylinder-positioning-assembly in one end thereof and said locking assembly in the other end thereof;
• said outer-cylinder-positioning assembly having said movable sleeve with said hole on one side thereof, which being in communication with a round hole on one side of said outer cylinder, and one side of said round hole on said outer cylinder having a position-displacement slot;
• said locking assembly including a lock cylinder and a rotary cylinder with an inner portion which is mounted with a locking collar by means of a pin;
• said locking collar having a guide groove for said pin;
• and a spring being mounted between said locking collar and said lock cylinder;
• said locking collar having an unlocking recess;
• said through hole of said movable sleeve being perpendicular to a pin hole for receiving a fixing pin, and said fixing pin to be engaged with a circular groove on said rotary section;
• said movable sleeve being in contact with a spring which is retained in place with an end plug to be fixed in said outer cylinder with a pin.