Adjustable Pulley Assembly for Compound Archery Bow

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Solution Overview

Problem

Existing adjustable pulley assemblies for compound archery bows do not effectively alter the stored energy of the bow without changing the draw length or draw weight, limiting customization options for archers.

Innovation Solution

A reversible power module mounted on a draw cable pulley that can be rigidly attached in multiple positions and orientations, allowing for adjustments to the draw force curve and stored energy without altering the draw length or draw weight, by reversing the power module's orientation or repositioning it on the pulley.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If existing adjustable pulley assemblies are used to alter stored energy, then stored energy can be adjusted, but draw length or draw weight must be changed

Engineering Contradiction:

Improvestored energyVSAvoiddraw length

Core Design Contradiction:

Use of energy by moving objectVSLength of moving object

Solution Approach 1:

The pulley assembly is divided into separate functional modules: a draw cable pulley and a power cable pulley that can be independently adjusted. This segmentation allows the power cable pulley to be repositioned to change stored energy without affecting the draw cable pulley's position, thereby maintaining constant draw length while varying stored energy

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system employs adjustable and reconfigurable pulley positions that can be dynamically modified. The power cable pulley can be repositioned along the limb at different locations, and the power cable anchor point can be moved to different positions on the power cable, enabling dynamic adjustment of stored energy independent of draw length

Inventive Principle:

Principle #15Dynamics

2Use of energy by moving object

If existing adjustable pulley assemblies are used to alter stored energy, then stored energy can be adjusted, but draw weight must be changed

Engineering Contradiction:

Improvestored energyVSAvoiddraw weight

Core Design Contradiction:

Use of energy by moving objectVSForce

Solution Approach 1:

The independent modular design of the power cable pulley system allows separate adjustment of stored energy parameters without affecting draw weight. By repositioning only the power cable pulley and anchor point while keeping the draw cable pulley fixed, the system can vary stored energy while maintaining constant draw weight

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The adjustable configuration system enables dynamic repositioning of the power cable pulley along the limb and the power cable anchor point on the cable itself. This dynamic adjustment capability allows the system to achieve different stored energy levels while maintaining the same draw weight through strategic repositioning

Inventive Principle:

Principle #15Dynamics

3Length of moving object

If the power module is repositioned to adjust draw length or draw weight, then those parameters change, but stored energy cannot be adjusted independently

Engineering Contradiction:

Improvedraw lengthVSAvoidstored energy

Core Design Contradiction:

Length of moving objectVSUse of energy by moving object

Solution Approach 1:

The system separates the adjustment functions into two independent modules: draw cable pulley positioning controls draw length, while power cable pulley and anchor point positioning control stored energy. This segmentation allows draw length to be set first, then stored energy to be adjusted independently by moving only the power cable components

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system provides dynamic, multi-stage adjustability where the draw cable pulley position is first established to set draw length, then the power cable pulley and anchor point are independently repositioned to adjust stored energy. This dynamic sequential adjustment process enables independent control of both parameters

Inventive Principle:

Principle #15Dynamics

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

Enables precise adjustment of the bow's stored energy without changing the draw length or draw weight, providing archers with more customization options and performance variations.

Implementation Method 1

the draw cable pulley is structurally arranged so as to (i) define a first pulley assembly transverse rotation axis, (ii) be mounted on a first limb of an archery bow to rotate about the first pulley assembly axis, and (iii) receive a first end of a draw cable of the bow in a circumferential draw cable journal of the draw cable pulley, and (iv) let out the first end of the draw cable when the bow is drawn and the draw cable pulley rotates about the first pulley assembly axis

Methodology Applied

Scientific EffectRotation:

Implementation Method 2

the power module is structurally arranged so as to (i) receive a power cable of the bow in a circumferential power cable journal of the power module, and (ii) take up the power cable when the bow is drawn and the draw cable pulley rotates about the first pulley assembly axis

Methodology Applied

Scientific EffectCable take-up mechanism:

Data Source

PatentUS9417028B2Adjustable pulley assembly for a compound archery bow

Publication Date: 2016.08.16 BOWTECH LLC

AI summary

A pulley assembly for a compound bow comprises a draw cable pulley and a power module attached to the draw cable pulley and adjustable among one or more positions and two orientations. Changing the power module orientation at a given power module position alters the bow's draw force curve and stored energy without altering the bow's draw length or draw weight.