Single handrail telescopic ladder

A single handrail telescopic ladder, comprising:

• two front tubes and two rear tubes, wherein one of the two front tubes and one of the two rear tubes at the same side are hinged at a top;
• pedals for a user to step on are provided between adjacent front tubes and between adjacent rear tubes;
• a single handrail tube, which is scalability inserted into one of the two front tubes;
• one of the two front tubes is provided with a fixing hole that penetrates both inside and outside, and a locking hole corresponding to the fixing hole is provided at a corresponding position of the single handrail tube;
• a locking member, which simultaneously passes through the fixing hole and the locking hole after the single handrail tube is pulled out from one of the two front tubes to a predetermined position, thereby achieving a fixation between the single handrail tube and one of the two front tubes;
• and
• an elastic member, which directly or indirectly acts on the locking member and provides a pre-tension force for the locking member towards a direction passing through the fixing hole and the locking hole;
• when the locking member is unlocked, the locking member exits from the fixing hole and locking hole, allowing the single handrail tube to automatically retract into one of the two front tubes;
• wherein an installation seat is fixedly provided on an outer wall of one of the two front tubes, and a button is provided on the installation seat,
• wherein the elastic member is a spring;
• wherein a guide structure is provided between the button and the installation seat, and the guide structure is provided with a guide hole configured for one end of the spring to insert and a guide protrusion configured for the other end of the spring to be sleeved.