Forceps Wire Pulley Layout for Durability and Smooth Control
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Solution Overview
Problem
The durability of grasping-portion wires in forceps devices is compromised due to small radii of curvature when guide pulleys are closely arranged, and increased tension for grasping force leads to high frictional forces, affecting controllability.
Innovation Solution
The forceps device rearranges guide pulleys to increase the radius of curvature of grasping-portion wires by shifting them relative to each other and incorporating additional pulleys, with winding angles of 65° or more, and includes a bearing to reduce frictional forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the first guide pulleys and the second guide pulleys are arranged close to each other to wind the grasping-portion wires, then the wire routing is compact, but the radii of curvature of the wound grasping-portion wires become small, significantly lowering wire durability
Solution Approach 1:
The patent shifts the second guide pulleys laterally relative to the first guide pulleys, transitioning from a one-dimensional axial arrangement to a two-dimensional spatial configuration. This dimensional change allows the wire routing to achieve adequate bending radii while maintaining compact overall dimensions through optimized spatial positioning of the pulleys in both axial and lateral directions.
2Force
If the tensions of the grasping-portion wires are increased to increase the grasping force, then the grasping capability is improved, but the frictional force between the first rotating shaft and the support increases, lowering the controllability of the bending movement
Solution Approach 1:
The patent introduces a bearing as an intermediary component between the first rotating shaft and the support. This bearing reduces the frictional force generated by high wire tensions, acting as a mediator that allows high grasping forces to be transmitted while maintaining smooth rotational movement and controllability of the support structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the durability and controllability of the forceps device by reducing bending stress and friction, allowing smoother operation and improved wire longevity.
Implementation Method 1
the frictional force between the first rotating shaft and the support increases, which lowers the controllability
Data Source
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AI summary
A forceps device (10) includes a support (14) that holds a grasping part (12a, 12b), a first rotating shaft (16) that turnably supports the support, grasping-portion wires (26, 28, 30, 32) that transmit driving forces to move the grasping part, a guide pulley (20A) which is arranged coaxially with the first rotating shaft and over which a grasping-portion wire runs, and a guide pulley (34a) which is arranged upstream of the guide pulley (20A) and over which the grasping-portion wire runs. The guide pulley (34a) is (i) shifted toward one side relative to immediately below the guide pulley (20A) when the first rotating shaft is viewed in front in an axial direction in a state in which a leading end of a grasping part points upward, and (ii) arranged so that a winding angle γ of the grasping-portion wire around the guide pulley (20A) is 65° or larger at a neutral position at which the support is not turned to left or right.