Asymmetric Screw Drive Formation for Lower Screwing Effort
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Solution Overview
Problem
Existing screws require significant effort and energy to screw in and out, due to inefficient force transmission and mechanical losses.
Innovation Solution
A screw design featuring a shank with a thread and a drive formation at one end, comprising a circular-cylindrical or frustoconical main body with protuberances extending radially and tangentially counter to the screwing-in direction, allowing for secure positioning on a matching tool and reduced effort during screwing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional screw drive formations are used, then compatibility with existing tools is maintained, but significant effort and energy are required for screwing in and out due to inefficient force transmission
Solution Approach 1:
The drive formation features protuberances with asymmetric surfaces: a larger leading side surface in the screwing-in direction and a smaller trailing side surface. This asymmetry creates more favorable force transmission conditions during screwing-in, reducing mechanical losses and energy consumption while maintaining compatibility with existing tools.
Solution Approach 2:
The invention applies different surface properties to different parts of the drive formation. The leading side surfaces of the protuberances are designed with larger area and optimized geometry to enhance force transmission, while other parts maintain standard characteristics. This localized optimization reduces overall energy consumption without requiring complete redesign of the screw.
2Loss of energy
If standard drive formations are used, then manufacturing simplicity is maintained, but mechanical losses increase due to inefficient force transmission from the tool to the screw
Solution Approach 1:
The drive formation is segmented into a main body and multiple protuberances with distinct functions. The protuberances are further divided into leading and trailing sides with different surface areas. This segmentation allows optimization of force transmission at critical contact points while keeping the overall structure relatively simple and manufacturable.
Solution Approach 2:
The protuberances feature rounded outer ends and curved surfaces instead of sharp edges or flat surfaces. This curvature improves contact conditions with the tool, distributes stresses more favorably, and reduces mechanical losses during rotation, while remaining compatible with existing tool geometries.
3Ease of operation
If the protuberances are inclined counter to the screwing-in direction, then force transmission is improved and effort is reduced, but the drive formation becomes more complex
Solution Approach 1:
The protuberances are configured with asymmetric inclination angles relative to the screwing-in direction. The leading side surfaces are oriented to maximize force transmission during screwing-in, while the trailing side surfaces have different orientations optimized for unscrewing. This asymmetric configuration reduces effort during screwing-in while maintaining reasonable complexity through systematic design.
Data Source
AI summary
The invention relates to a screw (10; 70) with a shank (12), a thread (14) on at least one portion of the shank (12), wherein the thread (14) defines a screwing-in direction about a centre longitudinal axis of the shank (12), and with a drive formation (18; 78) at one end of the shank (12), wherein the drive formation (18; 78) has a depression (20; 80) in a screw head (16) or a projection at the end of the shank (12), wherein the depression (20; 80) or the projection in each case has a circular-cylindrical or frustoconical main body (22; 82), arranged concentrically with respect to a centre longitudinal axis (26) of the shank (12), and a number of protuberances (24; 84) which extend away from the main body (22; 82), wherein the protuberances (24; 84) are of rounded configuration at their radially outer ends, characterized in that the protuberances (24; 84) extend with a radial component with respect to the centre longitudinal axis (26), and with a component which is oriented tangentially and counter to the screwing-in direction.