Pick Tool Wear Shielding via Unitary Carbide Overhang
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pick tools with super-hard strike tips lack sufficient wear resistance, particularly in applications like road milling and mining, where abrasive wear is significant, and are often difficult to manufacture using certain hard cemented carbide materials due to joining challenges.
Innovation Solution
A pick tool design featuring a unitary cemented carbide support body with an overhang portion and a long, shrink-fitted insertion shaft, which provides enhanced wear protection and allows for the use of harder, more wear-resistant carbide materials, combined with a super-hard strike tip, such as polycrystalline diamond, to reduce abrasive wear and extend tool life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a steel base with a bore is used to accommodate the insertion shaft, then the pick tool can be manufactured with conventional joining methods, but the external surface of the base is susceptible to abrasive wear in road milling and mining applications
Solution Approach 1:
The support body is divided into a head portion and an insertion shaft portion that are integrally formed as a unitary cemented carbide component. This segmentation allows the head portion to provide wear protection for the base while the insertion shaft provides structural support and can be shrink-fitted into the base.
Solution Approach 2:
The invention uses a unitary cemented carbide support body that combines the hardness and wear resistance of cemented carbide materials with the structural requirements of the insertion shaft. This composite material approach allows the support body to shield the steel base from wear while maintaining manufacturability through shrink-fitting.
2Object-affected harmful factors
If harder cemented carbide materials are used for the support body to improve wear resistance, then abrasive wear is reduced, but joining the support body to the base becomes more difficult
Solution Approach 1:
The invention changes the joining method from conventional mechanical or brazing methods to shrink-fitting. This parameter change in the joining process allows harder cemented carbide materials to be used for the support body, as shrink-fitting does not require the same level of material ductility or compatibility as other joining methods.
Solution Approach 2:
The invention replaces conventional joining mechanisms (such as brazing or mechanical fastening) with a thermal-mechanical shrink-fit process. This substitution allows harder carbide materials to be used since the shrink-fit process relies on thermal expansion and contraction rather than material bonding compatibility.
3Reliability
If a relatively elongate insertion shaft is used to provide a wear-resistant core, then the shaft can remain in working condition even when the base is worn away, but the shaft is more difficult to shrink-fit into the base
Solution Approach 1:
The invention changes the joining process parameters to accommodate the elongate insertion shaft. By using shrink-fitting with controlled heating and cooling rates, the long shaft can be successfully joined to the base without excessive force requirements, making the process feasible despite the shaft's length.
4Object-affected harmful factors
If the overhang portion extends further radially over the external surface, then wear protection is improved, but the device complexity increases
Solution Approach 1:
The overhang portion is merged with the insertion shaft as a single integrally formed unitary cemented carbide component. This merging eliminates the need for separate wear protection components and simplifies the overall device structure while maintaining effective wear shielding of the base.
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
The design significantly enhances wear resistance and extends the working life of the pick tool by shielding the steel base from wear and allowing the use of harder carbide materials that are difficult to join by other means, reducing the rate of abrasive wear and maintaining the insertion shaft's integrity even when the forward-facing volume of the base is worn away.
Implementation Method 1
the base is provided with a bore into which the insertion shaft is shrink fitted
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A pick tool comprising a super-hard strike tip, a base and a unitary cemented carbide support body comprising a head portion including an overhang portion, and an insertion shaft extending from the head portion, a surface of the overhang portion extending laterally from the insertion shaft; the strike tip is attached to the head portion of the support body and the base is provided with a bore into which the insertion shaft is shrink fitted; the base has an external surface adjacent the bore and overhang portion of the head portion is configured to extend over at least an area of the external surface operative to shield the area from wear when in use.