Inline Crossbow Conversion Kit Draw-Lock Bar and Cocking Stirrup
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Solution Overview
Problem
Bow hunters face challenges with the differences in power stroke and draw weight between compound bows and crossbows, which affect arrow/bolt speed, penetration, and ease of use, particularly for those lacking sufficient strength to handle crossbows and the cumbersome re-cocking process.
Innovation Solution
A conversion kit and hybrid compound bow that allows a compound bow to be configured as an inline crossbow, featuring a draw-lock bar with a pistol grip and trigger-actuated string release, and a cocking stirrup for easy handling of high draw weights, enabling conversion between inline and traditional crossbow configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a crossbow uses high draw weight (150-225 lbs) to achieve deep penetration energy, then penetration is improved, but ease of operation deteriorates due to requiring two-handed cocking with leg and back muscles
Solution Approach 1:
The cocking mechanism is divided into two independent stirrups (first and second stirrups) that can be used separately or together. This segmentation allows users to distribute the cocking effort across different body parts or use mechanical assistance, making high draw weight bows more operable for users with varying strength levels.
Solution Approach 2:
The stirrup acts as an intermediary mechanical device between the user and the bow string. By placing the foot in the stirrup, the user leverages body weight and mechanical advantage to cock the bow, eliminating the need to directly pull the high draw weight string with hand muscles.
2Force
If a crossbow uses high draw weight to achieve deep penetration energy, then penetration is improved, but ease of operation deteriorates due to cumbersome re-cocking process
Solution Approach 1:
The dual stirrup configuration allows one stirrup to be used for cocking while the other remains positioned for rapid re-cocking. This segmentation enables quick transition between shots by simply moving the foot between stirrups rather than fully repositioning equipment.
Solution Approach 2:
The stirrups are pre-positioned and attached to the bow before shooting. The first stirrup can be used to cock the bow, and the second stirrup is already in place for immediate re-cocking, eliminating the need to search for or attach cocking equipment between shots.
3Speed
If a compound bow has long power stroke (18-24 inches) to achieve high arrow velocity, then speed is improved, but device complexity increases when adding draw-locking mechanisms
Solution Approach 1:
The stirrup assembly serves multiple functions: it acts as a cocking mechanism, a draw-locking device, and a support structure. By combining these functions into a single multi-functional component, the patent avoids adding separate complex mechanisms while still achieving draw-locking capability.
Solution Approach 2:
The draw-locking mechanism uses the user's own foot and body weight to secure the bow at full draw. The stirrup's position and the user's foot placement create a self-locking effect that maintains draw weight without requiring additional active components or continuous energy input.
4Measurement precision
If a crossbow is designed for shoulder mounting to achieve stable aiming, then accuracy is improved, but maneuverability deteriorates in brush or tree branches
Solution Approach 1:
The bow design allows dynamic switching between shoulder mounting mode (for accurate shooting) and handheld/carrying mode (for maneuverability). The stirrup and trigger assembly can be positioned to work with either mounting style, and the bow can be easily transitioned between configurations during hunting.
Data Source
AI summary
A kit is provided to convert a compound archery bow into a left or right handed inline (vertical limb) crossbow. The conversion kit includes a mounting plate attachable to a side of the bow riser section to hold a socket to receive a draw-lock bar which can be removed for take-down and storage. The draw-lock bar has a series of laterally spaced bolt holes to attach a grip with a trigger release latch assembly at a selectable draw length. The bar can be rotated and attached to either side of the bow, and the trigger and grip can be reposition within the trigger housing for left, right or horizontal shooting. The string latch assembly has an anti-dryfire lever that is only moved from the blocking position when an arrow is nocked. The kit also provides a hinged cocking stirrup, and a front hand vertical grip on the riser side opposite the draw-bar socket. Also disclosed is a dedicated hybrid compound bow for dedicated use with kit as an inline or traditional crossbow. The hybrid compound bow is made especially. The hybrid bow has no forehand grip, and has a shoot through riser to provide vertical and horizontal centering of the arrow to the string.