Expanded Hole Cutter Linkage for Stable Blade Rotation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hole expansion forming devices experience significant friction and instability during cutting blade operation, leading to uneven hole expansions and increased blade damage due to inadequate movement stabilization and structural limitations.
Innovation Solution
The device incorporates a cutting blade tool with blades on both ends turning around an intermediate portion, a biasing mechanism for automatic blade retraction, a spiral groove for efficient chip discharge, runout prevention features, depth adjustment adapters, and a torque transmitting element with a rotary shaft connecting element to ensure smooth and stable cutting blade movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a cutting blade is pushed by a cutting blade operation tool to turn during hole expansion formation, then the hole expansion can be formed in the joint hole, but great friction occurs between the cutting blade and the operation tool, causing rough movement and blade damage
Solution Approach 1:
The cutting blade is designed to rotate dynamically around an intermediate portion rather than being linearly pushed, allowing it to adapt its position and reduce friction during the hole expansion process. The blade can turn smoothly while maintaining contact with the wood surface, reducing resistance and preventing damage.
Solution Approach 2:
The cutting operation transitions from linear pushing motion to rotational motion around an intermediate axis. This dimensional change in movement pattern allows the blade to cut more efficiently with reduced friction, as rotation distributes the cutting force across different contact points during the turning cycle.
2Productivity
If the cutting blade turns by being pushed by the cutting blade operation tool, then the hole expansion is formed, but the movement in the turning direction becomes free and unstable, causing bumpy movement and uneven cutting
Solution Approach 1:
The cutting blade rotates dynamically around an intermediate portion during the hole expansion process, allowing smooth adaptation to the wood grain and curvature. This dynamic rotational movement ensures consistent cutting depth and uniform hole expansion formation, eliminating the bumpy movement caused by linear pushing constraints.
Solution Approach 2:
The intermediate portion acts as a mediator or pivot point around which the cutting blade rotates. This intermediary structure provides a stable center of rotation, ensuring controlled and uniform movement of the blade during cutting, which directly improves the precision and uniformity of the formed hole expansion.
3Strength
If the blade width of the cutting blade is increased to secure sufficient strength, then the blade can withstand greater cutting forces, but the blade cannot be further widened due to structural limitations
Solution Approach 1:
Instead of relying on increased blade width for strength, the blade utilizes dynamic rotational movement around an intermediate portion. This motion distributes cutting forces more effectively throughout the blade structure, allowing the existing blade dimensions to withstand the required cutting forces without structural modification.
Solution Approach 2:
The design replaces the mechanical approach of increasing blade width (structural strengthening) with a motion-based approach (rotational cutting). By substituting the cutting mechanism from linear pushing to rotation around an intermediate point, the system achieves sufficient cutting capability without needing to increase blade dimensions, thus avoiding structural complexity issues.
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
A device for forming an expanded hole section realizes smoother movement when turning of a cutting blade and stabilizes a movement in a rotating direction of the cutting blade when cutting, in a device which includes a cutting portion main body formed to have a diameter to be housed within a joint hole and including a cutting blade tool movable in a range from a housed position at which a blade is housed within the diameter to an extended position at which the blade projects out of the diameter, an advancing and retracting member that is moved in an axial direction by an external force and rotates integrally in an axis circumferential direction, and a link mechanism that converts advancing and retracting movement of the advancing and retracting member into movement of the cutting blade tool, a tip portion bearing that is provided on a tip end side of the cutting portion main body, and serves as a tip end side bearing by being housed in an inner side of the joint hole, and a torque transmitting element to transmit a torque in the axis circumferential direction to the advancing and retracting member, and forms a hole expansion in an inner wall of a joint hole formed to have a required depth in a joint surface of a wood member.