Excavation Blade Plate Shear Force Reduction
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Solution Overview
Problem
Conventional excavating apparatuses for forming continuous trenches face issues with increased shear force on fastening members due to variations in shape tolerance and fastening states, leading to potential loosening or disengagement of bolts, and instability in the excavation plane.
Innovation Solution
The apparatus features an endless-shaped chain with strip members and coupling members to maintain constant distance, and excavation blade plates with inward and outward protruding portions that contact strip members, reducing shear force by stabilizing the blade plates during excavation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a plate holder and base plate are used to connect bit plates and endless chain, then the connection is achieved, but the weight of the chain-type cutter increases and shear force on fastening members increases
Solution Approach 1:
The patent removes the plate holder and base plate from the connection structure, directly fastening the bit plate to the endless chain with bolts. This extraction of unnecessary components reduces the overall weight of the chain-type cutter while maintaining the connection function.
Solution Approach 2:
The connection structure is segmented into essential components only: the bit plate, endless chain, and fastening members. By dividing out the non-essential plate holder and base plate, the design achieves weight reduction while preserving the core fastening function.
2Reliability
If plate holder and base plate are used for connection, then fastening is achieved, but the load on the chain increases leading to potential damage
Solution Approach 1:
By removing the plate holder and base plate, the patent eliminates the intermediate layers that contributed to increased load. The direct fastening approach reduces the total load on the chain while maintaining reliable connection through proper bolt fastening.
3Ease of manufacture
If plate holder and base plate are positioned between bolt and nut, then fastening structure is complete, but shear force on bolt increases causing loosening or disengagement
Solution Approach 1:
The patent extracts the plate holder and base plate from between the bolt and nut, creating a direct fastening path. This eliminates the additional shear force that would be transmitted through multiple layers, reducing the risk of bolt loosening or disengagement.
Solution Approach 2:
Instead of having the bolt pass through multiple layers (plate holder, base plate, bit plate), the design inverts the approach by directly fastening the bit plate to the chain, reversing the traditional layered structure to reduce shear force accumulation.
4Ease of manufacture
If plate holder and base plate are used, then connection is achieved, but relative position of excavation bits changes due to tolerance variations
Solution Approach 1:
By removing the plate holder and base plate from the connection structure, the patent eliminates the cumulative tolerance effects that occur when multiple components are assembled together. The direct fastening approach ensures more consistent positioning of excavation bits.
Data Source
AI summary
Provided are an excavating apparatus, an excavation blade plate and an excavating method which are capable of reducing a shear force to be applied to a fastening member fixedly fastening the excavation blade plate and a chain together. The excavating apparatus comprises a cutter post, a chain, a plurality of cutter bit plates, and a shoe bolt S1. The chain 11 is formed by mutually coupling a plurality of pairs of links arranged along a circulating movement direction thereof Each of the cutter bit plates includes: a support-target surface supported by a supporting surface of the chain; and a central convex portion formed to protrude with respect to the support-target surface and inserted in a space between the pair of links, wherein the central convex portion is in surface contact with inner side surfaces of the pair of links along the circulating movement direction.