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Pub. No.:    WO/2018/040122    International Application No.:    PCT/CN2016/098631
Publication Date: Fri Mar 09 00:59:59 CET 2018 International Filing Date: Sun Sep 11 01:59:59 CEST 2016
IPC: E06C 1/12
Applicants: PAN, Yuejin
Inventors: PAN, Yuejin
Disclosed is a new extension ladder, comprising at least three ladder sections. The ladder sections comprise ladder leg tubes (1) and ladder rungs (2). Both ends of each ladder rung (2) are connected to a ladder rung support (3), the ladder rung supports (3) being connected to the ladder leg tubes (1); of the ladder sections vertically adjacent to each other, the upper ladder leg tubes (1) insert into the lower ladder leg tubes (1). The new extension ladder further comprises a tension snap ring lowering apparatus. The tension snap ring lowering apparatus comprises a tension snap ring (14) and a tension snap ring support (11), wherein a fastening hole (12) is provided above the tension snap ring support (11); an annular groove is provided at the lower end of the tension snap ring support (11); the tension snap ring (14) is seated within the annular groove; a fastening position is provided at the lower end of the inner wall of the upper ladder leg tube (1), said fastening position matching the fastening hole (12); and the tension snap ring (14) sits in tight contact with the inner wall of the adjacently lower ladder leg tubes tube (1). The new extension ladder is convenient to operate and is safer, and the connection between the ladder rungs is secure.