Tapered Lobular Driver Bit for Multi-Size Fastener Engagement
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Solution Overview
Problem
Existing torque transmission drivers are limited in their ability to efficiently engage and drive multiple sizes of fasteners, often leading to inefficiencies, mis-installations, and increased risk of cam-out, especially with small fasteners, due to their dedicated size requirements and susceptibility to driver cam-out and strip-out.
Innovation Solution
A torque transmission driver with a tapered bit featuring alternating series of 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 effective torque transmission across various fastener sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a driver is dedicated to one specific fastener size, then the engagement precision and torque transmission reliability are improved, but the device complexity increases and productivity decreases due to needing multiple drivers for different fastener sizes
Solution Approach 1:
The driver bit is designed with a tapered geometry that allows it to engage multiple fastener sizes (e.g., #6, #8, #10 screws) through a single interface. The taper angle (15°-45°) enables the driver to maintain proper alignment and torque transmission across different fastener dimensions, eliminating the need for multiple dedicated drivers and improving assembly productivity
2Force
If a driver with larger engagement surfaces is used, then the torque transmission capability is improved, but the risk of cam-out increases when driving smaller fasteners
Solution Approach 1:
The driver bit features a tapered geometry where the engagement surface dimensions vary along the length of the bit. When engaging smaller fasteners, the smaller-diameter portion of the tapered bit makes contact, providing appropriate engagement surface area that prevents cam-out. When engaging larger fasteners, the larger-diameter portion provides increased torque transmission capability
3Reliability
If a driver with smaller engagement surfaces is used, then the risk of cam-out is reduced for small fasteners, but the torque transmission capability decreases
Solution Approach 1:
The tapered geometry of the driver bit creates a dynamic engagement system where the contact surface area between driver and fastener varies based on fastener size. The operator selects the appropriate driver bit diameter matching the fastener size, which automatically optimizes the engagement surface area - smaller bits for small fasteners to prevent cam-out, larger bits for large fasteners to maximize torque transmission
4Reliability
If multiple dedicated drivers for different fastener sizes are used, then the torque transmission reliability for each size is improved, but the device complexity and loss of time increase
Solution Approach 1:
The tapered driver bit design allows a single driver to reliably engage multiple fastener sizes through proper geometric matching. The taper angle (15°-45°) ensures consistent alignment and torque transmission across different fastener dimensions, eliminating the need for operators to select between multiple dedicated drivers and reducing time loss
Data Source
Figure 1A~1D
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AI summary
The present invention relates to a torque transmission driver comprising: a main body having a first end portion and a second end portion; the first end portion adapted to receive and transmit torque from a torque generation source; the second end portion opposite the first end portion comprising a shaped tapered bit corresponding to a recess of similar shape and taper in a plurality of differently-sized fasteners; wherein the shaped taper bit includes a drive surface corresponding to a first torque direction, the drive surface adapted to engage a corresponding tapered fastener surface at a lift angle less than 2°. Further, the present invention relates to a driver.