Endoscope Bendable Part Length Change Mechanism

The patent applies dynamics by making the guide coil compressible along the longitudinal direction. The compression member can compress the guide coil to change it from an extended state to a compressed state, dynamically altering the bendable part's configuration. This allows the endoscope to switch between long-length bent state (for deep insertion) and short-length bent state (for small radius bending), resolving the contradiction between insertion maneuverability and bending capability.

The patent changes the physical parameters of the guide coil by compressing it along the longitudinal direction. When compressed, the guide coil's length decreases and its stiffness increases, enabling the bendable part to bend in smaller radii. This parameter change allows the endoscope to achieve both deep insertion capability and small radius bending by adjusting the compression state of the guide coil.

The patent applies nesting by placing the compression member inside the guide coil structure. The compression member is disposed inside the guide coil and can be advanced or retracted within it, allowing compression without requiring external complex mechanisms. This nested configuration achieves the function of changing bending radius while minimizing structural complexity.

The guide coil structure serves multiple functions: it provides the bendable characteristic of the endoscope, acts as a mechanical element that can be compressed to change stiffness, and serves as a housing for the compression member. This multi-functionality reduces the need for separate components, thereby reducing overall device complexity while achieving small radius bending capability.