Paving Machine Grade Propulsion System Rollback Prevention

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional paving machines experience rollback when starting from an inclined surface, leading to defects in the paving mat due to the disengagement of the braking mechanism, which is not effectively managed by existing technologies.

Innovation Solution

A propulsion system that includes a controller, a brake system, and an inclination sensor, which determines the current grade and calculates an offset current to ensure the propel current is sufficient to overcome rollback by disengaging the brake system when the propel current meets or exceeds the cracking current plus the offset current, thereby preventing rollback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the brake system is disengaged to start movement, then the machine can begin to move forward, but rollback occurs causing defects in the paving mat

Engineering Contradiction:

Improvestart movementVSAvoidpaving mat quality

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The system applies preliminary action by engaging the brake system before disengagement and maintaining it during the critical transition period. The controller monitors propel current and keeps the brake engaged until sufficient propel current is established, preventing rollback before it can occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The brake system provides preliminary anti-action by counteracting the gravitational force that causes rollback. The controller maintains brake engagement during the transition from stationary to moving state, creating an opposing force that prevents the harmful rollback motion before it can damage the paving mat.

Inventive Principle:

Principle #9Preliminary anti-action

2Manufacturing precision

If the brake system remains engaged to prevent rollback, then paving mat quality is maintained, but the machine cannot start movement

Engineering Contradiction:

Improvepaving mat qualityVSAvoidstart movement

Core Design Contradiction:

Manufacturing precisionVSSpeed

Solution Approach 1:

The system applies dynamics by making the brake system state changeable rather than fixed. The controller dynamically adjusts brake engagement based on real-time monitoring of propel current, transitioning from engaged to disengaged state at the optimal moment when sufficient propel current is achieved, enabling both prevention of rollback and initiation of movement.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The controller uses feedback by continuously monitoring the propel current and adjusting brake system operation accordingly. The feedback loop detects when propel current reaches the threshold level and automatically triggers brake disengagement, coordinating the transition to ensure both paving mat quality and movement initiation.

Inventive Principle:

Principle #23Feedback

3Reliability

If propel current is increased to prevent rollback, then rollback is prevented, but energy consumption increases

Engineering Contradiction:

Improverollback preventionVSAvoidpropel current consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system replaces the mechanical brake system with an electrical control system that monitors propel current and coordinates brake disengagement. This substitution allows for more precise and efficient control, reducing energy consumption by eliminating the need for excessive propel current and enabling smooth, coordinated transitions between brake engagement and propulsion.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9206562B2Grade propulsion system and method

Publication Date: 2015.12.08 CATERPILLAR PAVING PROD INC

AI summary

A grade propulsion system provided herein includes: a propel pump; a brake system; an operator control configured to receive and transmit a propel command and a Hill Mode activation; and a controller electronically coupled to the propel pump, the brake system, and the operator control, the controller configured, after activation of the Hill Mode and the propel command, to transmit a propel current to the propel pump and disengage the brake system when the propel current is equal to or greater than a cracking current plus an offset current.