Rotating Bit With Integral Washer for Debris Sealing
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Solution Overview
Problem
Existing bit and pick assemblies for road milling, mining, and trenching equipment suffer from premature wear and reduced lifespan due to axial movement and debris ingress, leading to poor bit rotation and increased maintenance costs.
Innovation Solution
A bit assembly featuring a unitary bit body with an integral washer portion and a slotted retainer with varying features, which reduces axial movement, forms a nearly 100% sealed area, and ensures nearly 100% uninhibited bit rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate washer is used with the bit assembly, then the bit can be retained in the bit holder, but axial movement occurs and gaps form allowing debris ingress
Solution Approach 1:
The patent combines the washer function directly into the bit body by forming an annular washer portion integrally with the bit body at the location where the washer would traditionally be positioned. This merging eliminates the gap between separate components that allows debris ingress while maintaining the retention function.
2Ease of manufacture
If traditional separate washer and retainer components are used, then the bit can be assembled, but the gap between components increases over time causing poor rotation
Solution Approach 1:
By integrating the washer portion directly into the bit body as a single component, the invention eliminates the relative movement and gap formation that occurs between separate washer and bit components during operation, thereby ensuring consistent bit rotation performance throughout the service life.
3Ease of manufacture
If separate washer components are used, then the bit assembly can be constructed, but maintenance frequency increases due to wear
Solution Approach 1:
The integral formation of the washer portion with the bit body creates a more durable assembly with fewer wear points. Since there is no separate washer to wear against the bit holder, and no gaps to allow debris ingress, the overall service life of the bit assembly is extended, reducing maintenance frequency.
4Reliability
If multiple separate components (washer, retainer, sleeve) are used, then the bit can be retained, but the device complexity increases
Solution Approach 1:
The patent reduces component count by integrating the washer function into the bit body itself. This merging simplifies the overall assembly while maintaining the retention function, as the integral washer portion works in conjunction with the retainer and sleeve without requiring a separate washer component.
Data Source
AI summary
A bit including a bit body and a shank depending from a bottom of the bit body. The bit body including an integral washer portion that extends to a rear annular flange and a tapered portion adjacent the rear annular flange. A diameter of the bit body axially and radially extending to a transition adjacent an outer diameter of the washer portion. The tapered portion includes an angle that is complementary to an angle of a countersink at a forward end of a bore of a bit holder, such that the matching contacting angles of the tapered portion and the countersink radially align the bit concentric with the bore of the bit holder. The bit includes a retainer disposed circumferentially about the shank, allowing the bit to be securely mounted in the bore of the bit holder while still allowing the bit to freely rotate within the bore. The rear annular flange of the washer portion seats against a front face of the bit holder, forming a close coupling between the rear annular flange and the front face of the bit holder, allowing minimal space between the two surfaces and reducing cutting fines and water slurry from migrating into the space between the outer diameter of the bit shank and the inner diameter of the retainer.