Break-away Spring Piston Rod Trigger Sprayer Assembly
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Solution Overview
Problem
The manufacturing costs of traditional trigger sprayers are high due to the large number of separate component parts and assembly steps required, which can be reduced by integrating a plastic spring and piston rod with breakable connections.
Innovation Solution
The integration of a plastic spring and piston rod as a single monolithic piece with breakable connections allows for assembly as one unit and subsequent separation, reducing the number of parts and assembly steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional separate metal coil spring and piston rod components are used, then the trigger sprayer achieves reliable mechanical function, but the manufacturing cost increases due to multiple parts and assembly steps
Solution Approach 1:
The patent combines the spring and piston rod into a single integral plastic component with a breakable connection. The spring arms and piston rod are formed as one monolithic piece through injection molding, eliminating the need for separate metal spring and piston rod components. This merging reduces the number of parts and assembly steps while maintaining the mechanical functions of both components.
Solution Approach 2:
The integral plastic component serves multiple functions simultaneously: it provides spring biasing force, acts as a piston rod for liquid displacement, and includes a breakable connection for controlled separation. This multi-functional design consolidates what were traditionally separate components into a single element that performs both spring and piston rod functions.
2Productivity
If the spring and piston rod are integrated as one piece with breakable connection, then the number of assembly steps is reduced, but the manufacturing precision required for the breakable connection increases
Solution Approach 1:
The breakable connection is pre-formed as an integral part of the molded plastic component during the injection molding process. The weakened section with reduced material thickness is created in advance as part of the single-shot molding operation, eliminating the need for post-molding operations to create the breakable connection. This preliminary formation of the breakable connection simplifies subsequent assembly while maintaining precision through mold-built features.
3Ease of manufacture
If a monolithic plastic spring and piston rod is used, then the manufacturing cost decreases, but the reliability of the connection between spring and piston rod may be affected
Solution Approach 1:
The monolithic plastic component includes a breakable connection that segments the spring arms from the piston rod upon activation. This controlled segmentation occurs at a pre-formed weakened section that breaks under operational stress, separating the spring function from the piston rod function. The segmentation design ensures reliable separation at the intended location while maintaining structural integrity elsewhere in the component.
Solution Approach 2:
The material thickness parameter is varied within the monolithic plastic component to create the breakable connection. The weakened section has reduced material thickness compared to other portions of the component, creating a controlled stress concentration point. This parameter change in material distribution allows the connection to break reliably at the designated location under operational loads while maintaining overall component strength.
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
This approach decreases manufacturing costs by minimizing the number of components and assembly steps, making large-scale production more economical.
Implementation Method 1
a pair of spring arms (104, 106) that are integrally connected with the piston rod by a pair of breakable connections (138, 142) between the spring arms and the distal end of the piston rod
Data Source
AI summary
A manually operated trigger sprayer has an integral plastic spring and pump piston rod that are connected by a breakable connection, whereby the spring and piston rod can be assembled to the trigger sprayer as one piece and are subsequently broken into two separate pieces in response to their assembly to the trigger sprayer, or subsequent manual operation of the trigger sprayer.