Patent ID: 9339089
Filing Date: 2016-05-17
CPC Classification: A43C,A44B

Claim Text:
1. A string length adjustment device comprising: a fixed housing including a drum rotation axis formed in a central region thereof; a rotation housing rotatably coupled with respect to the fixed housing; a winding drum inserted into the fixed housing and the rotation housing and including a winding part around/from which a string is wound or unwound; and a coupling unit guide shaft coupling the fixed housing to the rotation housing, the coupling unit guide shaft guiding up/down operations of the rotation housing for operations of winding or unwinding the string, wherein the coupling unit guide shaft includes elastic ribs and protrusions, the elastic ribs being elastically biased in an outward radial direction and the protrusions being formed on the elastic ribs, and wherein the rotation housing includes protrusion supports formed on walls of a shaft insertion hole of the rotation housing to support the protrusions.