Welded Hand Rake Tine Joint Strength
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Solution Overview
Problem
Forked tools and machinery attachments experience tine breakage and separation from the backbone due to inadequate welding, leading to premature failure and costly replacements.
Innovation Solution
A unique welding method that extends welds along the longitudinal length of one lateral surface, the full length of a vertical surface, and partially along the second lateral surface, creating an elongated fracture line to enhance the strength and durability of the tine-to-backbone connection, preventing total separation and fracture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional welding methods are used to attach tines to the backbone, then the manufacturing process is simple and cost-effective, but the tines will either totally separate from the backbone or fracture/break off under hard usage
Solution Approach 1:
The welding process is segmented into multiple passes: a first weld pass creates initial attachment, followed by a second weld pass that reinforces the connection. This segmentation allows the weld to develop strength progressively without excessive heat input that would weaken the backbone, while ensuring complete tine retention through the combined effect of multiple welding stages.
Solution Approach 2:
The first weld pass serves as a preliminary action that establishes basic tine-to-backbone attachment before the final reinforcing weld is applied. This preliminary welding creates a stable base structure that prevents tine separation during subsequent handling and final welding operations, ensuring reliability from an early stage in the manufacturing process.
2Ease of repair
If attempts are made to reweld the damaged tine to the backbone, then the tine can be reattached, but an annealing process occurs that results in further weakening of the backbone and the surrounding tines
Solution Approach 1:
The multi-pass welding approach with controlled heat input and proper cooling intervals prevents the annealing effect that would occur during repair welding. By establishing a strong, complete weld from the beginning through the two-pass process, the design preemptively counteracts any potential weakening that would result from subsequent heating or repair attempts, maintaining backbone strength throughout the tool's service life.
3Strength
If the welds are extended along the longitudinal length of one lateral surface, the full length of a vertical surface, and partially along the second lateral surface, then the strength of the tine to backbone juncture is increased, but the welding process becomes more complex and time-consuming
Solution Approach 1:
The welding process applies different weld characteristics to different surfaces of the tine: full longitudinal coverage on one lateral surface, complete vertical surface coverage, and partial coverage on the second lateral surface. This local quality approach concentrates welding effort on areas experiencing the highest stress and most critical for structural integrity, achieving maximum strength without the need for excessive welding on all surfaces equally.
Solution Approach 2:
The welding pattern is intentionally asymmetric, with one lateral surface receiving full longitudinal weld coverage while the second lateral surface receives only partial coverage. This asymmetric approach recognizes that stress distribution and structural requirements differ across various surfaces, optimizing strength where needed while reducing unnecessary welding complexity on less critical surfaces.
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 method significantly reduces tine breakage and separation, ensuring the tool retains all tines throughout its life, minimizing replacement costs and improving durability.
Implementation Method 1
welds are applied in a unique pattern to a lower section of each tine positioned on a backbone member of the tool head
Data Source
AI summary
A rake, pitchfork, or similar forked hand tool or tool head for mechanized machinery has welded tines. The tines each have a lower section located on the backbone of the tool head and a working section extending outwardly from the backbone. Each tine also has two lateral surfaces, two vertical surfaces and a transversely extending back edge surface therebetween. In one embodiment, welds extend the full length of one of the lateral surfaces, the full length of a vertical surface, the transverse length of the back edge surface and down the second vertical surface to the junction between the bottom of the vertical surface and the second lateral surface. Welds can also extend partially along the length of the second lateral surface for a distance not to exceed three quarters of its length. These tines have elongated fracture lines. The resulting tool is far less prone to breakage.