Exercise Machine Rocker Arm Dampener for Actuator Backlash

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Solution Overview

Problem

Exercise machines experience actuator backlash due to reversing loads during striding exercises, leading to undesirable noise and unbalanced user feedback.

Innovation Solution

Incorporation of a dampener system that applies a preload force on the actuator to dampen reversing loads, using a dual preload dampener system with tension and compression forces to reduce backlash.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a dampener is added to reduce actuator backlash, then noise is reduced and user feedback is improved, but device complexity increases

Engineering Contradiction:
ImprovenoiseVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

A dampener is introduced as an intermediary component between the actuator and the rocker arm linkage. The dampener absorbs and dissipates the harmful reversing loads and backlash forces, preventing them from being transmitted to the actuator and causing noise. This mediator approach allows the system to achieve noise reduction without fundamentally changing the actuator or linkage design.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The dampener is positioned to provide beforehand cushioning against the reversing loads that occur during the striding exercise motion. By placing the dampener in the load path before the forces reach the actuator, the system pre-absorbs the harmful vibrations and shocks, preventing them from causing noise and improving user feedback.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Ease of operation

If a dampener is added to reduce actuator backlash, then user feedback is improved, but device complexity increases

Engineering Contradiction:
Improveuser feedbackVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The dampener serves as an intermediary that filters and smooths the force transmission between the actuator and the rocker arm. This mediation improves user feedback by eliminating the harsh, unbalanced forces that would otherwise be transmitted to the user, while adding only a single component to the system.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The dampener provides beforehand cushioning against the reversing loads, creating a smoother, more balanced user experience. By cushioning the forces before they reach the user, the system improves ease of operation without requiring complex control systems or multiple actuators.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If a dual preload dampener system is used to reduce backlash, then actuator performance is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveactuator performanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The dampening system is segmented into two separate dampeners: a compression dampener and a tension dampener. Each dampener is optimized for its specific function, allowing for simpler individual manufacturing and assembly. The segmentation enables specialized manufacturing processes for each component while maintaining overall system reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the dampening system have different local qualities - the compression dampener is optimized for compressive loads while the tension dampener is optimized for tensile loads. This local optimization allows each component to be manufactured and tuned for its specific requirements, improving overall actuator performance while keeping individual manufacturing tasks manageable.

Inventive Principle:
Principle #3Local quality

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

Reduces actuator backlash, minimizing noise and ensuring a smooth, balanced user experience across varying incline configurations.

Implementation Method 1

A dampener is configured to apply a preload force on the actuator that dampens reversing loads from the rocker arm to thereby reduce backlash in the actuator

Methodology Applied
Scientific EffectDamping: Damping

Implementation Method 2

The dampener may comprise a spring

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 3

The dampener may comprise a spring configured to apply the compression force on the actuator

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4603155A1Exercise machines having dampener for reducing actuator backlash
Publication Date: 2025.08.20 LIFE FITNESS LLC
  • EP4603155A1 patent drawingFigure 1
  • EP4603155A1 patent drawingFigure 2
  • EP4603155A1 patent drawingFigure 3

AI summary

An exercise machine has a frame, a rocker arm operable to perform a striding exercise motion relative to the frame, an actuator coupling the rocker arm to the frame, the actuator being configured to adjust a position of the rocker arm relative to the frame to adjust an incline of the striding exercise motion, and a dampener configured to apply a preload force on the actuator to dampen reversing loads from the rocker arm and reduce backlash in the actuator.