Crossbow String Cocking Device Silent Ratchet and Dual Pawl Redundancy

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Solution Overview

Problem

Existing crossbow string cocking devices often produce a ratcheting noise, are large and heavy, have only one ratchet pawl, and require a winding string, which can lead to damage and injury, as well as scare game due to noise, and are cumbersome to transport.

Innovation Solution

A crossbow string cocking device with two ratchet pawls, a silent ratchet mechanism, reduced size and weight, and a winding ribbon, featuring a housing with reels, a ratchet device, rotary spring, and drive shafts to ensure quiet operation and enhanced safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single ratchet pawl is used, then the device structure is simpler, but the reliability decreases and catastrophic failure can cause damage and injury

Engineering Contradiction:

ImprovereliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies redundancy by incorporating a second ratchet pawl alongside the first ratchet pawl. This beforehand cushioning ensures that if one pawl fails, the other can still prevent catastrophic failure of the crossbow string, thereby improving reliability without requiring complex additional systems.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent changes the parameter of pawl quantity from one to two, transforming the reliability characteristic while maintaining relatively simple structure. This parameter change provides fail-safe operation without significantly increasing device complexity.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a ratcheting noise is produced, then the string can be latched, but the noise scares wild game and creates a harmful auditory signal

Engineering Contradiction:

Improvelatching reliabilityVSAvoidratcheting noise

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a silent ratchet mechanism as an intermediary between the string and the latching action. This intermediary mechanism provides the necessary latching function without producing the harmful ratcheting noise, thereby eliminating the adverse acoustic signal while maintaining reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional noisy mechanical ratcheting system with a silent ratchet mechanism. This substitution maintains the latching function through mechanical means while eliminating the harmful noise generation, achieving reliable operation without adverse acoustic effects.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If a winding string is used, then the string can be stored on a reel, but more structure and weight are required to ensure even winding

Engineering Contradiction:

Improvestring storage capabilityVSAvoidcocking device weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The patent extracts the string winding function from a complex reel system and integrates it into a simplified configuration where the string is wound directly on a lightweight reel component. This extraction reduces the overall structure and weight while maintaining the adaptability of string storage and even winding capability.

Inventive Principle:

Principle #2Taking out (Extraction)

4Reliability

If a large and heavy cocking device is used, then the ratchet mechanism can be robust, but the device becomes difficult to transport

Engineering Contradiction:

Improveratchet mechanism robustnessVSAvoidcocking device weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent segments the cocking device into modular components including a housing, reel, ratchet mechanism, and string pull device. This segmentation allows for optimized weight distribution and robust construction of critical components while maintaining overall portability. The modular design enables reliable operation without excessive weight.

Inventive Principle:

Principle #1Segmentation

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

The device operates silently, reduces the risk of catastrophic failure with dual pawls, and is more portable, preventing damage and injury while allowing for even string winding, ensuring a quieter hunting experience.

Implementation Method 1

a rotary spring, a driven shaft, a drive shaft

Methodology Applied

Scientific EffectSpring: Spring

Data Source

PatentUS9752844B1Crossbow string cocking device

Publication Date: 2017.09.05 HUANG DORGE O

AI summary

A crossbow string cocking device preferably includes a housing, a first reel, a second reel, a ratchet device, a rotary spring, a driven shaft, a drive shaft and a string pull device. The housing preferably includes a main body housing, a first end cover and a second end cover. The ratchet device is retained in a first end of the main body housing. A drive gear is rotatably retained on the drive shaft. The first reel and a ratchet gear of the ratchet device are retained on a first end of the driven shaft. A driven gear, the rotary spring and the second reel are retained on a second end of the driven shaft. The string pull device includes a ribbon and at least one string hook. A first end of the ribbon is retained on the first reel. A second end of the ribbon is retained the second reel.