Tapered Lobular Driver for Multi-Size Fastener Torque Transfer
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Solution Overview
Problem
Existing torque transmission drivers are limited in their ability to efficiently drive multiple sizes of fasteners, often leading to inefficiencies, mis-installations, and increased waste due to cam-out and the need for multiple drivers, especially in small fasteners with tight clearance tolerances.
Innovation Solution
A torque transmission driver with a tapered bit featuring alternating lobes and troughs with a taper angle between 15° and 45°, allowing engagement with multiple fastener sizes, and a drive side transition angle between 0° and 5° to reduce cam-out, enabling a single driver to effectively torque various sized fasteners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated driver size is used for each fastener size, then torque transmission reliability is improved, but device complexity and inventory requirements increase
Solution Approach 1:
The driver bit is designed with a tapered geometry that allows a single driver size to engage multiple fastener sizes. The taper angle of 15-45 degrees enables the driver to accommodate variations in fastener diameter while maintaining effective torque transmission, eliminating the need for multiple dedicated driver sizes.
Solution Approach 2:
The driver incorporates a variable taper angle (15-45 degrees) and adjustable drive surface geometry that adapts to different fastener sizes. This parameter variation allows the same driver to effectively engage fasteners of varying dimensions while maintaining reliable torque transmission.
2Device complexity
If a single driver size is used for multiple fastener sizes, then device complexity is reduced, but torque transmission reliability deteriorates
Solution Approach 1:
The driver bit features a tapered engagement surface with angles between 15-45 degrees, enabling a single driver to effectively engage multiple fastener sizes. This universal design maintains torque transmission reliability across different fastener dimensions without requiring multiple dedicated driver sizes.
Solution Approach 2:
The driver geometry incorporates dynamic adaptation through its tapered surfaces, allowing the engagement interface to adjust automatically to different fastener sizes. This dynamic characteristic ensures reliable torque transmission regardless of the specific fastener being driven.
3Ease of manufacture
If traditional drive systems are used, then ease of manufacture is improved, but cam-out and driver lifting occur under higher torques
Solution Approach 1:
The driver employs asymmetric tapered surfaces with specific angle ranges (15-45 degrees) that create a mechanical advantage against cam-out. The asymmetric geometry distributes contact forces more effectively, preventing driver lifting and cam-out even under high torque conditions while remaining manufacturable.
Solution Approach 2:
The tapered drive surfaces generate counteracting forces that prevent cam-out. The geometry creates a mechanical counterbalance to the lifting forces that occur during torque application, effectively resisting driver ejection from the fastener head.
4Power
If drive angle is increased to 10-20 degrees, then torque capacity is improved, but cam-out and lobe failure increase under higher torques
Solution Approach 1:
The driver optimizes the taper angle parameter within a specific range (15-45 degrees) to balance torque capacity and lobe retention. This parameter optimization ensures that sufficient torque can be transmitted while maintaining adequate engagement geometry to prevent lobe failure and cam-out under high torque conditions.
Data Source
AI summary
A torque transmission driver has a first end portion adapted to receive and transmit torque from a torque generation source, and a second end portion including a shaped tapered bit having drive surfaces with an alternating series of five or six lobes and troughs about a rotational axis, having a taper angle between 15 and 45° from the rotational axis operable to engage corresponding drive surfaces in a plurality of at least two size fasteners, the tapered drive surfaces of the bit comprising a first tapered portion operable to engage drive surfaces of a first sized fastener and a second tapered portion operable to engage drive surfaces of a second sized fastener, the drive surfaces of the second sized fastener being larger than the drive surfaces of the first sized fastener.