Adjustable Centering Mechanism for Hydraulic Pump Control Arms

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Solution Overview

Problem

Conventional hydraulic pump centering mechanisms in power machines are difficult to adjust, leading to potential creeping issues when the drive control actuators are not engaged, as small adjustments can be challenging to make accurately.

Innovation Solution

A centering mechanism for hydraulic pumps that includes a bracket assembly and biasing structure, allowing for easy adjustment by positioning a second bracket relative to a first bracket using threaded holes and slots, ensuring the control arm returns to the neutral position effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional pump centering mechanism is used, then the pump can maintain neutral position, but the adjustment is difficult and imprecise

Engineering Contradiction:
Improvecentering adjustment precisionVSAvoidadjustment ease
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The centering mechanism is divided into a first bracket (fixed to housing) and a second bracket (adjustable), allowing independent adjustment of the second bracket relative to the first. This segmentation enables precise positioning of the control arm while maintaining ease of adjustment through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second bracket is designed to be adjustably fixable to the first bracket, transitioning from a static fixed connection to a dynamic adjustable connection. This allows the operator to modify the centering position as needed, then secure it in the desired position for precise control.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the pump centering mechanism is made adjustable, then neutral position accuracy improves, but the device complexity increases

Engineering Contradiction:
Improveneutral position accuracyVSAvoidcentering mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

By segmenting the centering mechanism into two separate brackets with distinct functions (first bracket for mounting, second bracket for adjustment), the design achieves accurate neutral positioning without requiring a completely redesigned complex mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bracket assembly serves multiple functions: the first bracket provides structural mounting to the housing, the second bracket provides adjustable positioning, and together they enable both accurate centering and ease of adjustment. This multi-functionality reduces the need for additional separate components.

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

3Manufacturing precision

If the centering mechanism requires small precise adjustments, then neutral position accuracy improves, but the ease of operation decreases

Engineering Contradiction:
Improvecentering position precisionVSAvoidadjustment accessibility
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The adjustable second bracket can be positioned and secured at various precise locations relative to the fixed first bracket, allowing for fine-tuned centering adjustments. The modular nature makes these precise adjustments easier to perform compared to a monolithic mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bracket assembly acts as an intermediary mechanism between the control arm and the pump housing. By adjusting the second bracket's position relative to the first bracket, the system mediates the control arm's return position, enabling precise centering through a simple adjustable connection rather than complex internal pump adjustments.

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

The mechanism allows for easy and consistent adjustment of the pump centering, preventing unwanted movement of the power machine when the drive control actuators are not engaged, enhancing operational control and reliability.

Implementation Method 1

biasing structure operable to return the control arm to a centered position when an operating force is not applied to the control arm

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

adjusting fasteners, each adjusting fastener extending through an associated slot and threadable in an associated threaded hole to adjustably fix the second bracket to the first bracket

Methodology Applied
Scientific EffectThreaded fastening: Screw

Data Source

PatentEP2059674B1Two bolt adjustable centering system
Publication Date: 2018.08.01 CLARK EQUIPMENT CO
  • EP2059674B1 patent drawingFigure 1~2
  • EP2059674B1 patent drawingFigure 3
  • EP2059674B1 patent drawingFigure 4

AI summary

A centering mechanism for a hydraulic pump, a hydraulic pump assembly and a method of assembling a hydraulic pump assembly. The pump assembly generally includes a hydraulic pump, a control arm, and a centering mechanism. The pump generally includes a pump housing, a pump mechanism operable to control a flow of hydraulic fluid through the housing, the pump mechanism having a neutral condition in which fluid does not flow through the housing, a trunnion cap connectable to the housing, the trunnion cap and the housing cooperating to house the pump mechanism, and an input shaft extending along an axis and through the trunnion cap, the shaft being rotatable to operate the pump mechanism. The control arm is connected to the shaft, and movement of the control aπn causes rotation of the shaft. The centering mechanism may generally include a first bracket fixable to the housing, a second bracket adjustably fixable to the first bracket, and biasing structure operable to return the control aπn to a centered position when an operating force is not applied to the control arm. The second bracket is adjustable relative to the first bracket to an adjusted position such that the centered position corresponds to the neutral condition of the pump mechanism, the second bracket being fixable in the adjusted position. Fasteners fix the first bracket and the trunnion cap to the pump housing.