Fire Extinguishing Pistol Trigger Mechanism Play Reduction
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Solution Overview
Problem
Hand-held fire extinguisher guns face challenges in achieving precise dosing of extinguishing agents due to component tolerances and play, leading to reliability and accuracy issues, which are further complicated by environmental factors and cost considerations.
Innovation Solution
The design incorporates a slide element with adjustable passage cross-section and a lever with lugs and a connecting pin featuring axially extending notches, allowing for precise alignment and reduced play, along with radially projecting projections to support the slide element and reduce friction, enhancing accuracy and reliability while simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If component tolerances and clearances are reduced to improve triggering accuracy, then dosing precision improves, but reliability deteriorates due to risk of mutual locking under temperature changes and environmental influences
Solution Approach 1:
A connecting pin with axially extending notches is introduced as an intermediary component between the lever and housing. The notches create a ratchet-like engagement that allows controlled movement while preventing backward motion, thereby eliminating play without requiring tight clearances between moving parts. This mediator enables accurate triggering while maintaining reliable operation under environmental variations.
Solution Approach 2:
The invention changes the geometric parameters of the connecting pin by adding axially extending notches in its central portion. This structural modification transforms the pin from a simple cylindrical connector into a component with directional engagement features, allowing it to eliminate play in one direction while maintaining mobility in the operating direction, thus resolving the contradiction between precision and reliability.
2Measurement precision
If component tolerances are reduced to eliminate play and improve accuracy, then dosing precision improves, but manufacturing costs increase
Solution Approach 1:
Instead of reducing tolerances across all components, the invention applies a localized structural feature (axially extending notches) only to the connecting pin. This local modification eliminates play at the critical triggering interface without requiring high-precision manufacturing throughout the entire assembly, thereby achieving dosing precision while controlling manufacturing costs.
Solution Approach 2:
The adding of axially extending notches to the connecting pin represents a parameter change in the component's geometry. This modification enables the elimination of play through a simple structural feature rather than through tight tolerances, making the solution economically viable while achieving the required dosing precision.
3Ease of operation
If lubricant is applied to reduce friction and improve slide element movement, then operability improves, but reliability deteriorates due to lubricant aging and loss over time
Solution Approach 1:
The invention extracts the lubricant from the system by designing the connecting pin with axially extending notches that eliminate the need for lubrication. The notched structure reduces friction through its geometric design rather than relying on lubricant films, thereby improving ease of operation while maintaining long-term reliability without lubricant degradation issues.
Data Source
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AI summary
A fire extinguishing gun (1) has a housing (10) in which an extinguishing agent passage (11) is formed, the cross-section of which can be adjusted by means of a sliding element (20), the sliding element (20) being movable in the direction of its longitudinal axis to open and close the extinguishing agent passage (11). A lever (60) is provided which is connected to both the sliding element (20) and the housing, the lever (60) having a right and a left tab (66), each tab (66) having a through-hole (63) and both through-holes (63) being coaxial with each other.The housing has an eyelet (13) provided between the two through holes of the lever, and a connecting pin is inserted through the eyelet and the two through holes, the connecting pin having one or a plurality of axially extending, punched notches (51) in an axial central section, such that the axial central section of the connecting pin (50) is connected to the eyelet (13) of the housing in a displacement-resistant manner in the axial direction and rotationally resistant in the circumferential direction, but the two axial end sections, which do not have notches, are rotatably inserted into the two through holes (63).