Breech Block Timer Switch Calibration Without Fouling Drift
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Solution Overview
Problem
Conventional action timer switches in internal ballistic testing suffer from fouling and require frequent cleaning and recalibration, leading to inaccurate and non-repeatable timing measurements due to the spring-loaded ball switch mechanism, which complicates calibration and affects the reliability of propellant and ammunition evaluations.
Innovation Solution
An action timer start switch with a through-hammer adjustable contact and a contact switch fixedly supported on the breech block, allowing for precise calibration without disassembling the weapon test system, as the adjustable contact can be set by positioning the breech block in the in-battery position, eliminating the need for spring-based components prone to fouling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring-loaded ball switch mechanism is used in the action timer switch, then the switch can generate a start signal when the hammer strikes, but the ball face becomes flattened and the spring becomes fouled over time, causing the ball to stick and not return to its design-intent position
Solution Approach 1:
The patent removes the spring-loaded ball switch mechanism entirely and replaces it with a direct contact between the hammer face and a contact element. This extraction of the problematic spring and ball components eliminates the fouling issue while maintaining the start signal generation function.
Solution Approach 2:
The patent replaces the complex spring-loaded ball mechanical system with a simpler direct mechanical contact system. The hammer face directly contacts a contact element mounted on the breech block, eliminating the need for springs and balls that are prone to fouling.
2Ease of repair
If the adjustment mechanism for the action timer switch is accessed from the front face of the breech block, then the switch can be calibrated, but the test barrel must be removed from the universal receiver and the breech block must be moved to the out-of-battery position with the barrel in a vise
Solution Approach 1:
The patent inverts the adjustment access approach by providing access to the adjustment mechanism from the rear of the breech block rather than the front face. This allows calibration to be performed with the barrel installed in the universal receiver, eliminating the need for disassembly and vise mounting.
Solution Approach 2:
The patent enables the action timer switch to be self-calibrated by the operator without requiring external support equipment like a vise or removal from the universal receiver. The adjustment mechanism is made accessible from the rear, allowing the system to service itself in its normal installed state.
3Productivity
If the ball face is struck repeatedly by the hammer, then the start signal is generated for each round, but the ball face becomes flattened causing increased gap between the hammer and ball face, resulting in delayed switch closures
Solution Approach 1:
The patent removes the ball face component that deforms under repeated hammer strikes. By replacing it with a rigid contact element that does not deform, the system maintains consistent timing measurement accuracy throughout the service life regardless of the number of rounds tested.
Data Source
AI summary
An action timer start switch, a breech block with an integral action timer start switch and a system for measuring internal ballistic data in a test weapon system are described herein. The action timer start switch includes a through-hammer adjustable contact having a first contact element and a contact switch supported on the breech block having a second contact element. The first contact element is adjustable for contacting the second contact element when the hammer is a position to generating a primer strike. The first contact element may be set by simply positioning the breech block in the in-battery position with the hammer in the ignition position and moving the adjustable contact relative to the contact switch through the breech of the universal receiver.