Snowplow Blade Passive Downforce Hydraulic Circuit
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Solution Overview
Problem
Hydraulically actuated snowplow blades struggle to maintain contact with uneven or obstacle-laden surfaces, especially in heavy snow or ice conditions, due to insufficient weight, and existing active downforce mechanisms can lead to premature pump failure and harsh vehicle impacts.
Innovation Solution
A passive downforce mechanism that isolates the lift cylinder from the hydraulic pump, maintaining equal hydraulic pressure across both sides of the lift cylinder, generating a larger downforce than upforce, and incorporates a hydraulic accumulator to absorb pressure variations, reducing pump cycling and impact forces on the vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the snowplow blade relies on its weight to maintain contact with the plowing surface in float mode, then the blade can adjust to uneven terrain and obstacles, but the blade may ride up over heavy snow or ice when weight is insufficient
Solution Approach 1:
The patent applies counterweight principle by using a downforce mechanism that generates an additional downward force on the snowplow blade through hydraulic pressure applied to a downforce cylinder. This counteracts the insufficient weight of lightweight blades, ensuring continuous contact with the plowing surface even when encountering heavy snow or ice accumulation.
Solution Approach 2:
The system dynamically adjusts between float mode and downforce mode based on operational needs. The downforce mechanism can be activated when additional contact force is required and deactivated when terrain adjustment is needed, providing adaptive control over the blade's contact force with the plowing surface.
2Force
If a hydraulic lock is used to lock the snowplow blade in the down position, then downforce is provided for level surfaces, but the blade cannot move over small obstacles or adjust to uneven terrain
Solution Approach 1:
The system allows dynamic transition between locked down position and float mode. The hydraulic lock can engage to provide stable downforce on level surfaces, then disengage to allow the blade to float and adapt to uneven terrain or obstacles, providing operational flexibility.
Solution Approach 2:
The downforce mechanism is designed to work independently of the primary lift cylinder's float mode operation. It provides supplemental downforce when needed without interfering with the blade's natural floating behavior, allowing the system to self-adjust based on operational conditions.
3Force
If an active downforce mechanism with pressure switch and hydraulic pump is used, then additional force is provided to keep the blade in contact with the surface, but the constant actuation of the pump results in premature pump failure
Solution Approach 1:
Instead of continuous pump operation, the system uses periodic or on-demand activation of the downforce mechanism. The pump or actuator is activated only when additional downforce is required, rather than running constantly, thereby reducing wear and extending service life.
Solution Approach 2:
The patent extracts the downforce function from the primary lift system, creating a separate, independent downforce mechanism. This allows the downforce to be applied through a dedicated circuit that can operate independently, reducing the burden on the main hydraulic pump and allowing for more efficient, targeted operation.
4Force
If an active downforce mechanism is used, then downforce is provided, but impact forces are transmitted through the hydraulic system and mounting hardware directly to the vehicle
Solution Approach 1:
The downforce mechanism introduces an intermediary hydraulic circuit with accumulators and check valves that acts as a buffer between the blade and the vehicle chassis. This intermediary system absorbs and dampens impact forces, preventing direct transmission of shock loads to the vehicle structure and mounting hardware.
Solution Approach 2:
The hydraulic accumulators in the downforce circuit are pre-charged and positioned to provide cushioning before impact forces occur. When the blade encounters obstacles or uneven terrain, the accumulators absorb the shock before it can be transmitted to the vehicle, protecting the hydraulic system and mounting hardware from damage.
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
The passive downforce mechanism ensures the snowplow blade remains in contact with the surface while allowing adjustment over obstacles and uneven terrain, extending pump and vehicle hardware service life by reducing cycling and impact forces.
Implementation Method 1
incorporates a hydraulic accumulator to absorb pressure variations, reducing pump cycling and impact forces on the vehicle
Implementation Method 2
maintaining equal hydraulic pressure across both sides of the lift cylinder, generating a larger downforce than upforce
Data Source
AI summary
A snowplow blade articulator assembly includes a mounting frame for attaching a snowplow blade to a vehicle chassis. A hydraulic pump and a hydraulic reservoir are attached to the mounting frame, the hydraulic reservoir supplying hydraulic fluid to the hydraulic pump. An articulating assembly is attached to the mounting frame for moving the snowplow blade when the snowplow blade is attached to the mounting frame, the articulating assembly is fluidly connected to the hydraulic pump, and the articulating assembly includes a lift cylinder and a hydraulic manifold. The hydraulic manifold includes a downforce circuit that fluidly isolates the lift cylinder from the hydraulic pump when a first control valve is closed and the downforce circuit fluidly connects a lift chamber of the lift cylinder with a lower chamber of the lift cylinder to maintain equal hydraulic pressure in the lift chamber and in the lower chamber.