公开(公告)号：US20200337802A1

公开(公告)日：2020-10-29

申请号：US16392656

申请日：2019-04-24

Applicant: CHI-CHING HUANG

Inventor： CHI-CHING HUANG ,  MEI-HUI KAO

IPC: A61C1/08 ,  A61C8/00

Abstract: A telescopic casing includes first end portion, second end portion, first support spring, third end portion, and second support spring. Each of the first, second, and third end portions has a hollow tubular shape. Top end of first end portion is detachably coupled to dental handpiece. Top end of second end portion is nested by rear end of first end portion. First support spring is disposed in first end portion, wherein one end of first support spring abuts against top end of second end portion and the other end of first support spring abuts against first end portion. Top end of third end portion is nested by rear end of second end portion. Second support spring is disposed in second end portion, wherein one end of second support spring abuts against top end of third end portion and the other end of second support spring abuts against second end portion.