Reverse Tram Interlock for Hydraulic Trenchers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Walk-behind hydraulic trenchers are limited by safety standards to a slow reverse travel speed of 1.55 mph, which increases transportation time when trenching is done away from the vehicle, as operators must walk backward and the trencher cannot move efficiently in the forward direction when not trenching.
Innovation Solution
The implementation of a reverse tram interlock system that restricts reverse movement of traction levers while allowing full forward motion by diverting hydraulic fluid flow from the trenching pump to the transporting pump, enabling faster forward movement when the trencher is in transporting mode and limiting reverse speed to meet ANSI standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the trencher is limited to slow reverse travel speed to meet ANSI safety standards, then operator safety is ensured, but transportation time increases when trenching is done away from the vehicle
Solution Approach 1:
The trencher implements dynamic speed control based on operating mode. The interlock system allows the machine to operate at fast forward speeds during transport mode and automatically limits reverse speeds to ANSI requirements during trenching mode, optimizing both safety and efficiency across different operational states
Solution Approach 2:
The speed control function is segmented into mode-specific limitations. The interlock system separates forward and reverse direction control, allowing unrestricted forward speed for transport while enforcing speed limits only in reverse direction during trenching operations
2Productivity
If the trencher moves forward at fast speed when transporting, then transportation efficiency improves, but the operator safety risk increases if the machine can also move fast in reverse
Solution Approach 1:
The interlock system dynamically adjusts speed capabilities based on operational context. During transport mode, the machine permits high forward speeds for efficiency while maintaining ANSI-compliant reverse speed limits, creating a dynamic safety profile that adapts to the current operational state
Solution Approach 2:
Speed limitations are applied locally to specific directions and modes rather than uniformly. The forward direction allows high speeds for transport efficiency, while the reverse direction is subject to speed limits during trenching, creating directionally-differentiated safety controls
3Speed
If the trencher chain is disengaged for transporting, then the machine can move faster in forward direction, but the reverse speed limitation becomes more restrictive
Solution Approach 1:
The interlock system merges multiple control functions into a single integrated mechanism. The same interlock that controls chain engagement/disengagement also manages the speed limitations for reverse travel, reducing the need for separate control systems while achieving both transport and safety objectives
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 the trencher to move at a faster speed in the forward direction when not trenching while maintaining the required slow reverse speed, reducing transportation time and ensuring operator safety by adhering to ANSI speed limits.
Implementation Method 1
a return spring; and a plate with a directional control valve
Data Source
AI summary
The present Application discloses a trenching device with two operational modes, Mode 1 and mode 2. In Mode 1, the trenching lever is disengaged, the device does not trench, but only functions as a transporting unit in a forward direction with a maximum speed. In Mode 2, the trenching lever is engaged, the device starts trenching, but stops functioning as a transporting unit.