Crossbow String-Pulling Unit with Integrated Front Sight
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Solution Overview
Problem
The existing crossbow designs face issues such as string-pulling unit shanks rubbing against the barrel, causing abrasion, security concerns due to premature loading or trigger release, and limited functionality of the front sight.
Innovation Solution
A crossbow with a robust multi-functional string-pulling unit featuring two parallel shanks, a handle, and a crossbar that moves along the barrel's lateral faces, with the crossbar extending over the barrel and incorporating a front sight for aiming, ensuring the shanks remain parallel and securely positioned, preventing premature bolt loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the string-pulling unit shanks are made to pull the string, then the string can be loaded onto the crossbow, but the shanks rub against the barrel causing abrasion and damage
Solution Approach 1:
The patent introduces a groove structure as an intermediary element between the shank and the barrel. The groove guides the shank's movement path, ensuring it follows a predetermined trajectory that minimizes contact with the barrel surface. This mediator structure allows the shank to pull the string effectively while preventing direct rubbing and abrasion between the shank and barrel.
2Ease of manufacture
If the string-pulling unit is designed with simple shanks, then the structure is easy to manufacture, but the unit lacks security against premature loading or trigger release
Solution Approach 1:
The string-pulling unit is segmented into distinct functional components: the shank for pulling, the crossbar for positioning and preventing premature loading, and the front sight for aiming. Each segment performs a specific function, and together they provide both manufacturing simplicity and operational security. The crossbar segment specifically addresses the reliability concern by physically blocking premature bolt loading.
Solution Approach 2:
The crossbar serves multiple functions simultaneously: it positions the shanks relative to each other, prevents premature bolt loading by blocking the loading path, and provides mounting for the front sight. This multi-functionality enhances reliability without significantly complicating the manufacturing process, as it adds a single structural element with compound purposes.
3Adaptability or versatility
If the front sight is made as a separate component, then it can be adjusted independently, but the overall device complexity increases
Solution Approach 1:
The front sight is merged with the crossbar structure, forming an integrated assembly rather than separate components. The crossbar serves as both a structural element for the string-pulling unit and a mounting platform for the front sight. This merging reduces the total number of parts while maintaining the adaptability of independent front sight adjustment, as the sight can still be positioned and adjusted on the crossbar without requiring separate mounting hardware.
Data Source
AI summary
A crossbow includes a barrel, a wing supported on a front portion of the barrel, a string connected to the wing at two ends, a rear sight supported on a rear portion of the barrel, and a string-pulling unit movably supported on the barrel and adapted for pulling the string backward on the barrel. The string-pulling unit includes two parallel shanks, a handle and a crossbar. The shanks are movable along two parallel lateral faces of the barrel. The handle is connected to the shanks near a rear end of each of the shanks. The crossbar is connected to the shanks near a front end of each of the shanks and adapted for keeping the shanks in position relative to each other. Moreover, the crossbar extends over the barrel. A front sight is formed on the crossbar and adapted for cooperation with the rear sight during aiming.