Spray Gun Protective Liner and Cam Trigger Mechanism
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Solution Overview
Problem
Existing spray guns face issues with thread damage, alignment problems, leakage, and user discomfort due to wear and corrosion of aluminum bodies when used with liquid and air passages, and heavy trigger pull required for operation.
Innovation Solution
A spray coating system with a protective liner made of wear-resistant materials, a one-piece trigger assembly with a cam surface for reduced trigger pull force, and a spray gun head insert that mounts without threads, reducing wear and corrosion and improving ergonomics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If components are threaded directly onto the aluminum body, then assembly is simple, but threads become damaged or worn after repeated assembly and disassembly causing alignment problems, leakage, or performance issues
Solution Approach 1:
The spray gun assembly is divided into distinct segments: the aluminum body, a separate threaded insert component, and the attachable components (spray head, nozzle, air cap). The threaded insert is press-fitted into the aluminum body, providing durable threading that doesn't compromise the aluminum structure. This segmentation allows repeated assembly and disassembly of components without damaging the aluminum body threads.
Solution Approach 2:
A threaded insert component serves as an intermediary element between the aluminum body and the attachable components. This insert provides the threading function while being protected from direct exposure to corrosive liquids and repeated assembly stress. The insert acts as a mediator that absorbs wear and corrosion, preserving the integrity of the aluminum body.
2Device complexity
If liquid and air passages are routed directly through the aluminum body, then the structure is simple, but the aluminum body becomes susceptible to wear and corrosion by liquids causing plugging, leakage, and performance degradation
Solution Approach 1:
The liquid and air passages are extracted from the aluminum body structure and relocated to a separate protective liner component. This liner is made of corrosion-resistant material and contains all fluid pathways. By taking the passages out of the aluminum body, the aluminum is no longer exposed to corrosive liquids, eliminating wear and corrosion issues while maintaining structural simplicity through the integrated liner design.
Solution Approach 2:
A protective liner acts as an intermediary barrier between the corrosive liquids and the aluminum body. This liner contains all liquid and air passages, preventing direct contact between the aluminum and corrosive substances. The liner mediates the interaction between the fluid system and the structural body, protecting the aluminum from degradation.
3Device complexity
If the valve trigger is coupled at a high pivot joint above all liquid and air passages, then the trigger mechanism is compact, but the pivot joint is a substantial distance from valve abutment surfaces requiring heavy trigger pull that creates user discomfort
Solution Approach 1:
Instead of positioning the pivot joint high above the passages (conventional design), the invention inverts the arrangement by placing the pivot joint low, below the air passage. This inversion repositions the trigger mechanism so that the pivot joint is in close proximity to the valve abutment surfaces, reducing the required trigger pull force while maintaining compactness through the reconfigured geometry.
Solution Approach 2:
The trigger mechanism is repositioned in a different spatial dimension relative to the passages. Rather than extending upward from the passages, the trigger is configured to operate below the air passage, utilizing vertical space more efficiently. This dimensional repositioning reduces the moment arm distance to the valve abutment surfaces, decreasing the force required for operation.
Data Source
AI summary
A spray coating system is provided with features to improve resistance to wear and corrosion, while also improving ergonomics. The spray coating system may include a spray coating device having a body with a liquid inlet coupled to a liquid chamber, and a protective liner extending inside the liquid chamber, wherein the protective liner is fixedly coupled to the body without threads. The spray coating device also may include a liquid nozzle extending inside the protective liner, and a cap extending over the liquid nozzle.