Crossbow Rotor Support System for Reduced Oscillation

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Solution Overview

Problem

Conventional crossbow designs face issues such as cam exposure leading to damage during transport and use, wide profile making handling difficult, oscillation causing inaccurate shooting, limited power stroke, and inefficiency due to power cable routing angles, resulting in increased wear and tear on components.

Innovation Solution

A rotor support system with moveable limb and rotor couplers that position the rotor within the crossbow's footprint, reducing oscillation and allowing more efficient energy storage and transfer, and a thicker rotor coupler to reduce vertical force transmission, thereby enhancing accuracy and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the cam is mounted on the outside profile of the crossbow, then the cam can take up and release sufficient power cable, but the cam protrudes beyond the outer surfaces of the limbs causing damage during transport and storage

Engineering Contradiction:

Improvepower cable take-up capabilityVSAvoiddamage during transport and storage

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The rotor is nested within the space defined by the limbs, specifically positioned so that its rotational axis lies within the triangle formed by the limb ends and the target. This nesting approach allows the rotor to perform its power cable take-up function while being protected from external damage during transport and storage, as it does not protrude beyond the crossbow's outer profile.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention changes the positioning dimension of the rotor from external mounting to internal positioning within the limb-defined space. By defining the rotor's position in three-dimensional space relative to the limb ends and target, the design achieves sufficient power cable engagement while maintaining a compact profile that prevents damage during handling.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Use of energy by moving object

If the cam is mounted on the outside profile of the crossbow, then the cam can engage the power cable effectively, but the crossbow has a wide profile making it difficult to use, store and transport

Engineering Contradiction:

Improvepower cable engagementVSAvoidcrossbow profile size

Core Design Contradiction:

Use of energy by moving objectVSVolume of moving object

Solution Approach 1:

The rotor is nested within the triangular space formed by the two limb ends and the target, utilizing the existing internal volume of the crossbow structure. This nesting eliminates the need for external mounting, thereby maintaining an compact profile that is easy to store and transport while still providing effective power cable engagement.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The rotor position is defined in three-dimensional space within the crossbow's internal volume, rather than extending outward. This spatial repositioning reduces the crossbow's external dimensions without compromising the power cable engagement capability, as the rotor operates within the existing structural envelope.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If the power cable is routed at a large downward angle through the barrel, then the cable can be routed through the slot in the barrel, but the cable force causes the cams to lean or tilt leading to asymmetric rotation and increased wear

Engineering Contradiction:

Improvepower cable routingVSAvoidcam rotation symmetry and bearing function

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention changes the routing angle parameter of the power cable, reducing it from a large downward angle to a smaller angle that is more aligned with the horizontal plane. This parameter change minimizes the vertical component of the cable force, preventing the rotor from tilting and ensuring symmetric rotation, thereby reducing wear on bearings and improving reliability.

Inventive Principle:

Principle #35Parameter changes

4Device complexity

If the rotor is positioned at the limb ends closer to the trigger, then the crossbow structure is simplified, but the power stroke is limited

Engineering Contradiction:

Improvecrossbow structureVSAvoidpower stroke

Core Design Contradiction:

Device complexityVSLength of moving object

Solution Approach 1:

The rotor position is defined in three-dimensional space, allowing it to be placed forward of the vertical plane extending between the limb ends while still maintaining structural simplicity. This spatial flexibility enables a longer power stroke without significantly increasing device complexity, as the rotor's position is optimized for both performance and structural efficiency.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS10612883B2Rotor support system and method for archery bows

Publication Date: 2020.04.07 TOG-IP LLC

AI summary

A rotor support system and a related method are disclosed herein. The rotor support system, in an embodiment, includes a limb coupler and a rotor coupler. The limb coupler is configured to be moveably coupled to a crossbow limb of an archery crossbow so as to enable a first movement of the limb coupler relative to the crossbow limb. The rotor coupler is configured to be moveably coupled to a rotor of the archery crossbow so as to enable a second movement of the rotor relative to the rotor coupler. The limb coupler and the rotor coupler are operably coupled.