Sloped Recess Joining Method for Mass Production
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Solution Overview
Problem
Existing methods for joining workpieces using threaded fasteners in woodworking are not suitable for mass production as they require manual clamping of a drill guide, which is inefficient and prone to errors.
Innovation Solution
A method involving the formation of a sloped recess with a notched ledge in one workpiece, allowing a threaded fastener to be inserted and driven through, eliminating the need for clamping and guide devices, using a CNC router to precision-machine the recess and guide the fastener.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual clamping of a drill guide is used to join workpieces, then the joining process can be performed with simple equipment, but the productivity is low and the process is not suitable for mass production
Solution Approach 1:
The recess is pre-formed in the workpiece with the exact geometry needed to guide the threaded fastener. This preliminary action eliminates the need for manual clamping and guide devices during assembly, enabling high-speed automated production while maintaining precision.
Solution Approach 2:
The guiding function is extracted from the separate drill guide device and integrated directly into the workpiece through the pre-formed recess. This eliminates the need for external guiding equipment and manual clamping operations.
2Manufacturing precision
If manual drilling and positioning methods are used, then the equipment requirement is simple, but the manufacturing precision is insufficient for consistent quality
Solution Approach 1:
The recess is pre-formed with precise dimensions and angles that automatically guide the threaded fastener to the correct position and orientation. This preliminary precision work eliminates the need for manual positioning and ensures consistent joining accuracy.
Solution Approach 2:
The recess acts as an intermediary structure that mediates between the workpiece and the threaded fastener. It provides the precise geometric constraints needed for accurate positioning without requiring complex positioning equipment or manual operations.
3Reliability
If threaded fasteners are driven without a guiding recess, then the process is simpler, but cracks may occur in the workpiece material
Solution Approach 1:
The recess is pre-formed to provide a gradual transition zone that distributes the stress from the driven fastener. This preliminary preparation prevents stress concentration that would cause cracks in the workpiece material.
Solution Approach 2:
The recess structure provides beforehand cushioning by creating a gradual transition zone that absorbs and distributes the impact forces when the threaded fastener is driven into the workpiece, preventing cracks from forming.
Data Source
AI summary
A method of joining a first workpiece having a first surface and a second surface angularly disposed relative to such first surface, and a second workpiece having a surface disposable in abutting relation relative to the second surface of such first workpiece, comprising forming a recess in the first surface of such first workpiece, sloped toward and spaced from the second surface of such first workpiece, producing an end surface thereof disposed at an angle relative to a longitudinal centerline of such recess; forming a notched ledge on the end surface of such recess; positioning a threaded fastener in the sloped recess with a head portion thereof resting on a bottom surface of the recess and the threaded portion thereof disposed along the centerline with the end thereof resting on such ledge; disposing the surface of the second workpiece in abutting relation with the second surface of the first workpiece; and threading the threaded fastener along the longitudinal centerline of such recess, through such abutting surfaces of such workpieces to join such workpieces together.