Trigger Sprayer Piston Rod With Integral Spring and Pivoting Connection
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Solution Overview
Problem
Conventional trigger sprayers with integral plastic springs face issues of liquid leakage due to force components exerted by the spring distorting the sealing engagement of the piston in the pump chamber during reciprocation.
Innovation Solution
A trigger sprayer design featuring a piston rod with integrally formed bowed springs and a pivoting connection between the piston rod and piston assembly, which isolates radial force components, maintaining axial alignment and preventing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal coil spring is used to bias the pump piston, then the piston can be reliably returned to the discharge position, but the device complexity and manufacturing cost increase
Solution Approach 1:
The spring is integrated directly into the piston rod structure, forming a unified component rather than a separate assembly. The piston rod includes a spring housing portion and the spring itself, eliminating the need for separate spring retainers, housings, and assembly steps. This merging maintains the reliability of piston return while significantly reducing device complexity and manufacturing cost.
2Ease of manufacture
If an integral plastic spring is used in the piston rod, then manufacturing cost is reduced, but liquid leakage occurs due to distorted piston sealing engagement
Solution Approach 1:
The spring is designed with flexibility to dynamically adapt its position and force application during piston reciprocation. The spring can flex and adjust to maintain optimal contact between the piston sealing surface and the pump chamber wall, compensating for variations in piston movement and ensuring continuous reliable sealing throughout the charge and discharge cycles.
Solution Approach 2:
The spring's physical parameters such as wire diameter, coil spacing, and overall length are optimized to generate appropriate force characteristics. By carefully controlling these parameters, the spring exerts sufficient force to maintain piston sealing engagement without applying excessive radial forces that would distort the piston or cause leakage, thus maintaining reliability while using a cost-effective plastic material.
3Device complexity
If the spring is integrally connected to the piston rod, then component quantity is reduced, but radial force components distort the piston axial alignment
Solution Approach 1:
The spring is positioned and oriented to apply force locally at specific points on the piston rod, rather than distributing force uniformly in all directions. By strategically locating the spring's attachment points and designing its winding direction, the spring generates primarily axial compressive forces while minimizing radial force components, thus maintaining the piston's axial alignment with the pump chamber during reciprocation.
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 reduces manufacturing costs by eliminating the need for a metal coil spring and allows all components to be constructed of plastic, enhancing recyclability and preventing liquid leakage during piston reciprocation.
Implementation Method 1
A pump piston rod with an integral plastic spring is provided in lieu of a conventional metal coil spring
Implementation Method 2
When the pump piston is moved to its charge position, the piston is retracted out of the pump chamber. This creates a vacuum in the pump chamber that draws liquid from the bottle, through the dip tube and into the pump chamber.
Implementation Method 3
When the pump piston is moved to its discharge position, the piston is moved into the pump chamber. This compresses the liquid in the pump chamber and pumps the liquid from the pump chamber, through the liquid discharge passage of the sprayer housing and out of the trigger sprayer
Data Source
AI summary
A manually operated trigger sprayer is constructed with a reduced number of parts and in a novel manner in which the conventional metal coil spring is replaced with a pair of plastic bowed springs that are integral with the piston rod and the pump piston is connected to the piston rod by a pivoting connection that prevents radial force components acting on the piston rod from the springs from being transferred to the pump piston.