Patent ID: 11926513
Assignee: HUVITZ CO., LTD.
Field: Handling (Mechanical engineering)
Classification: CPC B  F | IPC B  F

Claim 3:
4. The up-and-down driving device of claim 1, wherein the variable-position compression spring supplemental module (200) comprises:
a cylindrical shaft (201) having a space formed therein and one end mounted on the side of the fixed housing (120) so as to be rotatable around a first rotation shaft (210);
a circular column shaft (203) configured to be inserted into an inner space of the cylindrical shaft NON (201), and having one end mounted on the up-and-down driving unit (150) so as to be rotatable around a second rotation shaft (220); and
the variable-position compression spring (250) configured to be inserted into the inner space of the cylindrical shaft (201) and to surround an outer side of the circular column shaft (203), and mounted between the first rotation shaft (210) and the second rotation shaft (220) to change its length by an elastic force.