Shotgun Magazine Selector Interrupter Mechanism
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Solution Overview
Problem
Shotguns with dual magazine tubes often experience a malfunction known as 'lock up' when the magazine selector is manipulated before the fore-end has returned to its full extent of travel, causing shells to be released from both tubes simultaneously, leading to improper feeding and chambering.
Innovation Solution
A feeding system that includes movable blocking surfaces on each magazine tube, actuated by cams and springs, and a selector mechanism that prevents manipulation until the fore-end is fully returned to battery, ensuring proper selection and feeding from either tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the magazine selector is manipulated before the fore-end returns to full travel extent, then the operator can select a magazine tube, but shells are released from both magazine tubes simultaneously causing lock up malfunction
Solution Approach 1:
The patent applies preliminary anti-action by positioning an interrupter surface on the receiver that physically blocks the selector from being manipulated until the fore-end has returned to its full extent of travel. This preemptive mechanical constraint prevents the harmful condition (selector manipulation during fore-end travel) before it can occur, eliminating the risk of simultaneous shell release from both magazine tubes while still allowing magazine selection when proper timing is used
2Reliability
If a mechanism prevents selector manipulation except at full fore-end travel, then lock up malfunction is avoided, but the device complexity increases with additional components
Solution Approach 1:
The patent employs an interrupter surface as an intermediary element that mediates between the selector mechanism and the fore-end travel cycle. This simple geometric feature on the receiver acts as a mechanical gatekeeper, using the existing fore-end movement to automatically control selector availability without requiring additional active components, thus maintaining simplicity while ensuring reliability
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
Prevents the 'lock up' malfunction by ensuring that shells are not released from both magazine tubes simultaneously, allowing for reliable and safe operation by allowing magazine selection only when the action is fully in battery, thus ensuring proper feeding and chambering.
Implementation Method 1
A right biasing spring acts on the right outer cut-off and biases the right blocking surface into the first position
Implementation Method 2
The right cam is engageable with the right cam follower for moving the right blocking surface between the first and the second positions
Data Source
AI summary
A shotgun has right and left magazines from which ammunition may be fed to the action using a selector mounted on a movable fore-end chassis whose motion cycles the action. An interrupter prevents the selector from switching between magazines unless the action is in battery with the fore-end chassis fully forward toward the muzzle end of the shotgun. Respective right and left outer cut-offs on the magazines cooperate with an inner cut-off to ensure proper coordination of ammunition feed as the action is cycled by motion of the fore-end chassis. The outer cut-offs are also manually operable to permit removal of ammunition from the magazines without cycling the action.