Segmented Bow Cam Journals for Self-Timing and Lower Cable Wear

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Solution Overview

Problem

Existing archery bows face issues with cam lean, excessive cable wear, and inefficient mechanical draw-force characteristics due to the use of helical cable journals, which cause premature cable failure and difficult timing adjustments.

Innovation Solution

A self-timing cam configuration with five stacked journals sharing a common axis, featuring flat power cable journals and transition zones with smooth radial surfaces, allowing cables to slideably engage with cams without radial extensions, reducing wear and enhancing mechanical efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If helical cable journals are used to guide cables on cams, then the cables can be wrapped around the cam, but the cables experience excessive wear and premature failure due to friction and angular pressures

Engineering Contradiction:

Improvecable longevityVSAvoidcable wear

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The cable journal is divided into multiple flat segments arranged radially around the cam axis, each segment having a flat surface that contacts the cable. This segmentation allows the cable to transition between segments with minimal friction, eliminating the continuous angular pressure of helical journals and reducing cable wear while maintaining reliable cable guidance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using a helical groove that forces the cable to climb at an angle, the patent inverts the approach by using flat radial segments where the cable contacts flat surfaces. This inversion eliminates the angular pressure and friction inherent in helical designs, significantly reducing cable wear and extending cable life.

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of operation

If cables are routed off-angle to avoid interfering with arrow flight, then arrow clearance is achieved, but cam lean is created due to twisting and torque in the cam axle

Engineering Contradiction:

Improvearrow flight clearanceVSAvoidcam alignment

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent moves the cable routing from a two-dimensional off-angle path to a three-dimensional radial arrangement around the cam axis. Multiple flat segments are positioned at different radial angles, allowing the cable to maintain proper alignment with the cam axis while clearing the arrow path through vertical and radial positioning, thus eliminating cam lean.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The flat segmented journal acts as an intermediary between the cable and the cam axis, allowing the cable to transfer force radially without creating twisting moments. The segmented structure mediates the cable's path, enabling it to clear the arrow while maintaining proper cam alignment through radial rather than angular contact.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If binary cam system is used with opposing cams, then mechanical efficiency is improved, but timing adjustments become difficult and cam lean is created

Engineering Contradiction:

Improvemechanical efficiencyVSAvoidtiming adjustment complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The segmented flat journal design enables the binary cam system to self-time automatically. The radial segments allow the cables to engage and disengage at precise moments during cam rotation without requiring manual timing adjustments. The geometry of the flat segments inherently controls the timing sequence, eliminating the complexity of manual timing while maintaining high mechanical efficiency.

Inventive Principle:

Principle #25Self-service

4Strength

If helical cable journals with deep grooves are used to retain cables, then cable retention is achieved, but the journal edges create friction and wear on the cables

Engineering Contradiction:

Improvecable retentionVSAvoidfriction and wear

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

Each flat segment of the journal has a locally optimized flat contact surface rather than a continuous helical groove. The flat surfaces provide adequate cable retention through their radial positioning and geometry, while eliminating the edge friction problems of deep helical grooves. The local flat geometry provides retention without the harmful edge contact that causes wear.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20260049787A1Bow Cam Having Unique Cable Journals

Publication Date: 2026.02.19 BARNETT OUTDOORS LLC

AI summary

A cam for an archery bow having flat segmented power cable tracks or journals. The cam preferably includes five stacked journals sharing a common axis. The middle journal receivable for a bowstring with opposing mirrored and segmented cable journals above and below the bowstring journal plane. Alternately, the cam having three stacked journals; a bowstring journal and two segmented cable journals. A bowstring and cable(s) interact with the cam(s) and other components to fire a projectile, such as an arrow.