Trigger Sprayer Defected-Circular Shaft for Wear-Resistant Rotation
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Solution Overview
Problem
Conventional trigger sprayers experience a change in ease of rotation due to fatigue and deterioration of parts over time.
Innovation Solution
The trigger sprayer features a support shaft portion with a defected-circular cross-section and a support hole portion with a circular shape, creating a space between their peripheral edges to reduce wear and maintain rotatability, along with a spring mechanism to facilitate smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the trigger portion is pivotally attached to the body portion using conventional support shafts and support holes, then the trigger sprayer can be manufactured with simple structures, but the ease of rotation of the trigger portion deteriorates over time due to fatigue and wear
Solution Approach 1:
The support shaft portion is designed with a defected-circular cross-section featuring an arch-shaped portion that contacts the support hole portion, while other areas are reduced or eliminated. This local quality change concentrates the contact area to a specific arch portion, reducing wear and maintaining ease of rotation over time while still allowing for relatively simple manufacturing processes.
2Stability of the object's composition
If the support shaft portion has a circular cross-section fitting tightly into the support hole portion, then the structural stability is improved, but the ease of rotation changes due to fatigue and deterioration of parts
Solution Approach 1:
The support shaft portion is designed with an asymmetric defected-circular cross-section featuring an arch-shaped contact portion, deviating from the conventional symmetric circular design. This asymmetric design creates a specific contact geometry between the support shaft and support hole that maintains structural stability while reducing wear on the rotation interface, thereby preserving ease of rotation over time.
3Reliability
If the support shaft portion is designed with a defected-circular shape creating space between the peripheral edge and support hole portion, then the ease of rotation is maintained for longer periods, but the manufacturing complexity increases
Solution Approach 1:
The support shaft portion's cross-sectional geometry is modified by changing the parameter of the circular shape to a defected-circular shape with an arch-shaped portion. This parameter change creates the necessary space between the support shaft and support hole peripheral edges, reducing contact wear and maintaining ease of rotation, while the modification remains compatible with standard injection molding processes.
Data Source
AI summary
Trigger sprayer 100 comprises main body portion 1 having flow path 11, cylinder portion 13 formed in the flow path, and nozzle opening portion 12 located at a tip of the flow path; trigger portion 2 supported by support shaft portions 20 provided on both sides of the main body portion; piston portion 3 connected to the trigger portion; and spring portion 4 forcing the trigger portion forward. The piston portion slides along an inner wall of the cylinder portion based on the forward and rearward rotation of the trigger portion. Support hole portion 21 formed in the trigger portion to be attached to the support shaft portion has circular shape in side view. A cross section of the support shaft portion perpendicular to the axial direction is defected-circular shape, and a space is formed between a peripheral edge of the support hole portion and the support shaft portion.