Crossbow Trigger Anti-Dry-Fire Mechanism
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Solution Overview
Problem
Conventional crossbows are limited in their ability to fire multiple bolts in rapid succession, lacking the mechanism to efficiently load and launch multiple projectiles without manual reloading and safety mechanisms to prevent dry firing.
Innovation Solution
A multiple-shot crossbow design featuring parallel longitudinal rails with grooves to guide bolts, a riser for bolt insertion, upper and lower bow limbs with independent bowstrings, and a trigger mechanism with independent actuation for each string, including anti-dry-fire mechanisms to prevent accidental firing without a bolt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional single-shot crossbow design is used, then the structure is simple and easy to manufacture, but the crossbow can only fire one bolt at a time requiring manual reloading
Solution Approach 1:
The crossbow is divided into separate upper and lower firing systems, each with its own rail, bowstring, and trigger portion. This segmentation allows independent operation of each rail, enabling rapid successive firing without manual reloading while maintaining manageable structural complexity through modular design
Solution Approach 2:
The mainframe structure serves multiple functions by supporting both upper and lower rails, providing a common mounting platform for both firing systems. This multi-functionality increases productivity by allowing two bolts to be fired in succession while avoiding the need for completely separate structural systems
2Productivity
If multiple bolts are loaded on the crossbow for rapid firing, then the productivity increases, but the risk of dry firing increases if bolts are not properly loaded
Solution Approach 1:
The trigger mechanism includes feedback mechanisms that detect whether a bolt is properly loaded on each rail before allowing discharge. The separate trigger portions are designed to sense the presence of bolts and prevent activation if no bolt is detected, providing automatic feedback control for each firing system
Solution Approach 2:
The crossbow requires bolts to be pre-loaded onto the rails before the trigger can be actuated. The design ensures that the preliminary action of loading the bolt is completed and verified before the firing sequence can begin, preventing dry fire through pre-condition checking
3Ease of operation
If independent trigger portions are used for upper and lower rails, then each bolt can be fired independently improving control, but the trigger mechanism complexity increases
Solution Approach 1:
The trigger mechanism is segmented into separate upper and lower trigger portions, each controlling its respective rail independently. This segmentation provides ease of operation by allowing selective firing of either rail while managing complexity through modular, repetitive design elements that can be manufactured and assembled as standardized components
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
Enables rapid and safe firing of multiple bolts by allowing independent actuation of upper and lower bowstrings, ensuring that each bolt is properly loaded and preventing damage from dry firing, enhancing the crossbow's efficiency and safety.
Implementation Method 1
each bowstring can independently (i) be drawn from a corresponding brace position to a corresponding drawn position while deforming the corresponding bow limbs and (ii) return to the corresponding brace position and thereby launch a bolt positioned on the corresponding rail
Data Source
AI summary
A crossbow including at least one trigger assembly that may have a string catch, a sear, a trigger actuator, and an anti-dry-fire mechanism. The anti-dry-fire mechanism can include (i) a bolt sensor movable between a bolt-absent position and a bolt-present position, and (ii) a linearly reciprocating sear latch movable between a latched position and an unlatched position and biased toward the latched position. The bolt sensor may be pivotably coupled to the sear latch so that (i) with the bolt sensor in the bolt-absent position, the sear latch is held in the latched position by bias force thereon, and (ii) with the bolt sensor held in the bolt-present position, the sear latch is held in the unlatched position against the bias force thereon. When in the latched position, the sear latch can prevent movement of the sear.