Pivotable Hydraulic Pump Cable Tension Control
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Solution Overview
Problem
Existing construction machines with cable winches struggle to maintain a consistent and adjustable cable tension over a wide operating range, particularly during drilling operations, leading to inefficiencies and potential wear on the equipment.
Innovation Solution
A construction machine equipped with a pivotable hydraulic pump and a control device that manages the hydraulic flow in both directions, allowing for independent unwinding speed of the winch and precise control of cable tension, along with a force-measuring device for feedback and adjustment of cable tension based on measured values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional hydraulic circuit with a fixed-direction pump is used, then the winch can operate in one direction, but the cable tension cannot be adjusted over a wide operating range and the system lacks versatility for both lifting and lowering operations
Solution Approach 1:
The hydraulic pump is designed as a pivotable pump that can change its delivery direction dynamically. This allows the pump to supply hydraulic flow in both directions to the hydraulic motor, enabling the winch to perform both lifting and lowering operations with active cable tension control in each direction, thus achieving wide operating range adaptability without requiring multiple pumps or complex valve systems
Solution Approach 2:
The pivotable hydraulic pump serves multiple functions: it can generate hydraulic flow in both directions for bidirectional winch operation, and it can be controlled to provide precise cable tensioning force during both lifting and lowering. This single component replaces what would traditionally require separate systems for lifting, lowering, and tension control, achieving versatility while managing complexity
2Reliability
If a free-fall clutch or simple hydraulic circuit is used for cable tensioning, then the system structure is simpler, but the cable tension control precision and reliability are insufficient
Solution Approach 1:
A force measuring device is integrated into the hydraulic circuit to measure the actual cable tension in real-time. This measured force is fed back to the control device, which adjusts the pivot angle of the hydraulic pump to maintain the desired cable tension. This closed-loop feedback control ensures high reliability and precision in cable tension control, preventing both excessive tension and insufficient tensioning
Solution Approach 2:
The invention replaces mechanical tensioning devices (such as free-fall clutches with friction-based tension control) with a hydraulic control system. The hydraulic pump, controlled by electronic control device based on force feedback, provides precise and reliable cable tension control without the wear and imprecision inherent in mechanical friction-based systems
3Power
If the winch speed is controlled to match cable load, then energy efficiency improves, but the productivity and operational speed are reduced
Solution Approach 1:
The pivotable hydraulic pump enables independent control of winch speed and cable tension. The hydraulic motor can rotate at high speed for rapid cable unwinding during lowering operations, while the pump simultaneously adjusts its delivery pressure and flow to maintain the required cable tension. This dynamic decoupling allows the winch to operate at full productivity speed while maintaining optimal power utilization through active tension control
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
Ensures reliable and adjustable cable tensioning force during both lifting and lowering operations, preventing excessive wear and ensuring safe and trouble-free operation by allowing for program-controlled adjustments according to specific operating modes.
Implementation Method 1
the hydraulic motor is driven in a hydraulic circuit by a hydraulic pump, which is designed as a pivotable hydraulic pump, by which a hydraulic flow can be generated in both directions
Implementation Method 2
A force measuring device is provided for measuring the cable pull force and that the force measuring device is connected to the control device for controlling/regulating the hydraulic pump as a function of measured cable pull force values
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a construction machine and a method for controlling a construction machine with a mast along which a tool is movably mounted. The tool is suspended from a cable, which can be operated to raise and lower the tool by means of a winch. The winch is driven by a hydraulic motor. The hydraulic motor is driven in a hydraulic circuit by a hydraulic pump, which is designed as a pivoting hydraulic pump capable of generating a hydraulic flow in both directions. A control device is provided for controlling the hydraulic pump, which is designed to control the hydraulic pump depending on a predefinable cable tension force.