Spreader Frame Hydraulic Pressure Control for Constant Spring Rate

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Solution Overview

Problem

The spring rate of agricultural application devices' deployment linkages is dependent on their pivoting position due to the spring force exerted by hydraulic accumulators, leading to inconsistent suspension hardness.

Innovation Solution

The control device decouples the spring rate from the pivoting position by allowing predefinable pressure on the effective cylinder surfaces, which can be regulated using a pressure control device, including a pressure specification device and controllable valves, to independently set the spring rate and damping of the deployment linkage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If hydraulic accumulators are used to provide spring force for the deployment linkage, then the deployment linkage can be suspended and controlled, but the spring rate becomes dependent on the pivoting position, resulting in inconsistent suspension hardness

Engineering Contradiction:
Improvesuspension hardness consistencyVSAvoidspring rate independence from position
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The hydraulic system is segmented into separate functional components: a hydraulic cylinder for position control, a hydraulic accumulator for spring force, and a pressure control device for independent pressure regulation. This segmentation allows each component to perform its specific function without interference, enabling the spring rate to be controlled independently from the pivoting position.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the pressure parameter of the hydraulic fluid in the accumulator independently of the mechanical position of the deployment linkage. By using a pressure control device that regulates pressure based on flow rate rather than position, the spring rate (which depends on pressure) can be maintained constant or adjusted independently, resolving the contradiction between suspension hardness consistency and position independence.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the spring rate is decoupled from pivoting position using pressure control, then suspension hardness consistency is improved, but the device complexity increases due to additional pressure control components

Engineering Contradiction:
Improvesuspension hardness consistencyVSAvoidpressure control device complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The pressure control device is designed to perform multiple functions: it controls the pressure in the hydraulic accumulator to maintain consistent spring rate, regulates the overall hydraulic system pressure, and provides damping control. By consolidating these functions into a single multi-functional device, the increase in complexity is minimized while achieving the desired stability in suspension hardness.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If pressure control devices are added to regulate effective cylinder surface pressure, then spring rate can be set independently, but the device complexity and cost increase

Engineering Contradiction:
Improveindependent spring rate settingVSAvoidcontrol device complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention introduces a pressure control device as an intermediary component between the hydraulic pump and the hydraulic cylinder. This intermediary regulates the pressure of the hydraulic fluid before it reaches the effective cylinder surfaces, enabling independent spring rate setting without requiring complex direct control mechanisms on the cylinder itself. The pressure control device acts as a mediator that simplifies the overall control architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 allows for consistent suspension hardness and adjustable damping, improving the stability and maneuverability of the deployment linkage regardless of its position, enhancing operational efficiency and precision in applying substances.

Implementation Method 1

The two effective cylinder surfaces are each connected to a hydraulic accumulator, so that the piston and with it the two effective cylinder surfaces are resiliently mounted

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Accumulator

Implementation Method 2

the spring force exerted by the hydraulic accumulators on the piston changes

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3629725B1Control device for a spreader device, and spreader device having a control device
Publication Date: 2021.03.31 ARGO HYTOS GRP AG
  • EP3629725B1 patent drawingFigure 1
  • EP3629725B1 patent drawingFigure 2~4
  • EP3629725B1 patent drawingFigure 3

AI summary

The invention relates to a control device (40, 240, 440) for an agricultural spreader device (10, 210, 410), comprising a spreader frame (14, 214, 414) swivellably mounted on a carrier (12, 212, 412), and on which frame spreader elements (22, 222, 422) are arranged for spreading liquid and/or solid materials. The control device (40, 240, 440) has a pressure supply connection (62, 268, 468) and a return connection, (64, 270, 470), as well as a controllable valve assembly (60, 266, 466) and a hydraulic cylinder assembly (41, 241, 441) connected to the valve assembly (60, 266, 466) and having a first active surface (51, 255, 455) of the cylinder and a second active surface (52, 265, 465) of the cylinder, wherein the two active surfaces of the cylinder can be supplied with pressure and each is connected to a hydraulic accumulator (98, 100, 318, 320, 524, 544), and wherein the swivel position of the spreader frame (14, 214, 414) can be altered by changing the switch state of the valve assembly (60, 266, 466). In order to develop the control device (40, 240, 440) such that the spring rate of the spreader frame (14, 214, 414) can be decoupled from its swivel position, according to the invention, the active surfaces of the cylinder can be supplied with a predefinable pressure, regardless of the swivel position of the spreader frame (14, 214, 414). The invention also relates to an agricultural spreader device (10, 210, 410) having a control device (40, 240, 440) of this type.