Hand Tool Engaging Structure with Arcuate Contacts for Torque
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Solution Overview
Problem
Conventional socket structures for hand tools suffer from increased diameter due to protruding stop ribs, inadequate torque, and cause wear or serration on screw heads, limiting their effectiveness and durability.
Innovation Solution
An engaging structure with a mounting element featuring six drive portions and receiving portions, each with distinct faces and arcs, allowing for three rotational modes to engage screw members with large area contact or force concentration, preventing wear and serration while maintaining a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If stop ribs are projected in the engaging hole to maintain rotation force and torque, then the socket thickness is maintained, but the outer diameter of the socket is increased
Solution Approach 1:
The patent replaces the conventional sharp pointed stop ribs with arcuate receiving portions that have curved surfaces. The arcuate shape allows for better force distribution and engagement with the rounded corners of screw heads, maintaining effective torque transmission while reducing the need for protruding structures that increase outer diameter.
Solution Approach 2:
The invention changes the geometric parameters of the engaging structure by using arcuate receiving portions with specific radius ratios (R1/R2 between 0.5-2.0). This parameter optimization allows the receiving portions to effectively engage rounded screw head corners without requiring excessive projection depth, thus maintaining torque while controlling outer diameter.
2Force
If stop ribs have a sharp pointed shape to engage screw heads, then engagement is achieved, but the rotation torque is not large enough and screw heads are easily worn out
Solution Approach 1:
The patent employs arcuate receiving portions with curved surfaces instead of sharp pointed stop ribs. The arcuate shape better matches the rounded corners of modern screw heads, distributing contact stress over a larger area. This prevents stress concentration that leads to wear and chamfering, while maintaining sufficient engagement force through the curved geometry.
Solution Approach 2:
The arcuate receiving portions are designed with predetermined radius ratios (R1/R2 between 0.5-2.0) that anticipate and accommodate the rounding of screw head corners during repeated use. This pre-cushioning design prevents direct impact and stress concentration on already-rounded corners, reducing wear and extending service life.
3Speed
If stop ribs engage screw heads successively to rotate them, then rotation is achieved, but serration is easily caused on the screw head
Solution Approach 1:
The arcuate receiving portions with curved surfaces provide smooth, continuous contact with the screw head corners during rotation. This curved engagement eliminates the abrupt successive engagement of sharp stop ribs, reducing impact loads and preventing serration while maintaining effective rotation speed.
Solution Approach 2:
By optimizing the radius ratio (R1/R2 between 0.5-2.0) of the arcuate receiving portions, the invention creates a engagement geometry that smoothly guides rotation. This parameter optimization ensures continuous contact during rotational motion, eliminating the jerky successive engagement that causes serration on screw heads.
4Object-affected harmful factors
If a large interval is defined between the groove and angled corner of the screw head, then the engaging hole cannot easily rub the angled corner, but the socket needs greater thickness to maintain torque
Solution Approach 1:
The arcuate receiving portions with curved surfaces naturally guide the screw head corners into proper engagement positions, eliminating the need for large intervals between grooves and corners. The curved geometry provides self-aligning engagement that protects corners from rubbing wear while maintaining compact socket thickness.
Solution Approach 2:
By changing the engagement geometry from sharp stop ribs to arcuate receiving portions with optimized radius ratios, the invention reduces the required interval between engagement features. This parameter change allows effective corner protection with smaller dimensions, maintaining compact socket thickness while preventing rubbing wear.
Data Source
AI summary
An engaging structure for a hand tool includes a main body provided with a mounting element having six drive portions and six receiving portions. Each of the drive portions includes a first face, a second face, and a third face. A first intersection point is located at an intersection of the first face and the second face. A second intersection point is located at an intersection of the first face and the third face. Each of the receiving portions is an arcuate concave face. The mounting element has a first hexagon. The first face of each of the drive portions coincides with each of the sides of the first hexagon. The first hexagon has six first angled corners. The first arc of each of the six receiving portions is situated outside of each of the six first angled corners.