Snowmobile Throttle Bushing Gap Design for RPS Reliability

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Solution Overview

Problem

Snowmobile throttle control levers tend to warp, causing the throttle housing to squeeze and preventing the throttle lever from moving freely, which in turn affects the proper functioning of the Runaway Prevention Switch (RPS) when a side load is applied.

Innovation Solution

The implementation of a pair of bushings with a hole and closed ends on either side of the axle pin maintains a controlled gap between the throttle lever and the control housing, allowing the thumb lever to flex open under side load and preventing binding, ensuring proper RPS function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the throttle lever legs are rigid and closely fitted to the control housing, then the structural stability is improved, but the lever cannot move freely under side load and the RPS does not function properly

Engineering Contradiction:

Improvestructural stabilityVSAvoidlever movement freedom

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The throttle lever is divided into two separate legs that can move independently relative to each other, allowing the lever to flex open under side load while maintaining structural stability through the controlled gap design between the legs and control housing

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A controlled gap is introduced as an intermediary space between the throttle lever legs and the control housing, allowing the lever to move freely under side load without binding, while still maintaining proper structural support and stability

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the throttle lever is designed with flexibility to prevent warping, then the RPS function is improved, but the lever may become loose and affect precision control

Engineering Contradiction:

ImproveRPS functionVSAvoidcontrol precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The controlled gap between the throttle lever legs and control housing is precisely defined with specific dimensional parameters (e.g., 0.005 to 0.015 inches), allowing the lever to flex sufficiently for RPS function while maintaining precision control through controlled tolerances

Inventive Principle:

Principle #35Parameter changes

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

This solution allows the throttle lever to move freely even under side load, ensuring the RPS functions correctly and preventing potential runaway issues in snowmobiles.

Implementation Method 1

the thumb lever is allowed to flex open when a side load is applied

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS7717222B2Snowmobile throttle control top hat design

Publication Date: 2010.05.18 HONEYWELL INTERNATIONAL INC

AI summary

A snowmobile throttle control apparatus includes a pair of bushings with a hole and closed ends and a separate axle pin. The bushings are assembled to a thumb lever and mounted over the axle pin. The axle pin allows for a controlled gap to be maintained between the throttle lever, bushing assembly and the control housing. The thumb lever is allowed to flex open when a side load is applied. Thus allowing the thumb lever assembly to travel without binding on the control housing. This insures proper functioning of the RPS feature.