Chisel With Wavy Ribs for Subsoil Jamming
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Solution Overview
Problem
Conventional chisels tend to jam in subsoil due to compressive stresses, requiring significant physical effort to remove, as they penetrate and displace material without effectively managing shear stresses.
Innovation Solution
The chisel features a spreader body with wavy ribs that create alternating shear stresses by deflecting tangentially to the axis, reducing the likelihood of jamming by introducing shear forces that counteract penetration depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the chisel penetrates the ground along its axis building up compressive stresses, then the chisel can break up the subsoil into fragments, but the chisel will jam in the subsoil if the stresses exceed the load-bearing capacity
Solution Approach 1:
The ribs are formed in a wave shape with tangential deflection that is arcuate (circular) along a circumferential direction about the axis. This curvature creates alternating shear stresses as the chisel penetrates, reducing the tendency to bind while maintaining effective material breakdown
Solution Approach 2:
The spreader body is divided into multiple ribs running along the axis and distributed around the axis. Each rib independently creates shear stresses, and the segmented structure allows material to be broken up more effectively while reducing overall jamming tendency through distributed stress patterns
2Ease of operation
If the ribs are deflected with large amplitude, then shear stresses are reduced and jamming is minimized, but mining efficiency decreases due to excessive tilt
Solution Approach 1:
The amplitude of the deflection is optimized to be less than the width of the rib, with specific angular ranges (5-20 degrees). This parameter optimization ensures sufficient shear stress generation to prevent jamming while maintaining adequate inclination for effective mining operation
Solution Approach 2:
Different sections of the rib have different deflection characteristics, with the waveform creating localized alternating shear zones. The cross-section shape continuously changes along the axis in parallel deflection embodiments, creating localized quality variations that optimize both shear stress generation and mining efficiency
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design minimizes jamming and enhances mining efficiency by allowing easier extraction of the chisel from subsoil, balancing force distribution and reducing the need for excessive physical effort.
Implementation Method 1
The alternating deflection causes shear stresses in the subsoil which reduce a tendency of the bit to bind
Data Source
Figure 1
Figure 2~4
Figure 5~7
AI summary
The chisel (1) has a striking surface (4), a shank (8), a spreading element (12) and a tip (3) arranged successively along an axis (2), where the spreading element around the axis includes multiple ribs extending along the axis. The ribs include a wave shape formed with tangential deflection with respect to the axis. Amplitude of the deflection is less than width of the rib. Amplitude of deflection of sections of the rib extending in a circumferential direction is equal to amplitude of the deflection of sections of the rib extending contrary to the circumferential direction.