Cable Storage Device Dynamic Drum Speed Control

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Solution Overview

Problem

Motor-driven cable storage devices for inspection cameras face issues with excessive unwinding and insufficient tension, leading to loosened cable windings on the storage drum, making it difficult to rewind the cable compactly, and existing solutions like buffer sections require significant length and generate unnecessary tensile forces.

Innovation Solution

A cable storage device with a rotatably mounted storage drum and a control device that automatically adjusts the drum drive based on the fill level of a variable cable buffer, allowing dynamic unwinding and winding without user intervention, using a measuring device to determine the fill level and control the drum drive's speed and direction to maintain optimal tension.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a buffer section is used to compensate for pulling movements, then cable tension fluctuations are reduced, but the overall length and device complexity increase significantly

Engineering Contradiction:
Improvecable tension stabilityVSAvoidbuffer section length
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cable storage device employs dynamic speed adjustment of the storage drum based on real-time cable speed detection. The control unit continuously monitors cable speed and adjusts drum rotation speed accordingly, replacing the static buffer section with a dynamic control system that compensates for pulling movements without requiring excessive buffer length

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A sensor detects cable speed and feeds this information to the control unit, which then adjusts the drum drive speed. This closed-loop feedback system enables real-time compensation for cable tension fluctuations, achieving reliable cable handling without the need for a long buffer section

Inventive Principle:
Principle #23Feedback

2Reliability

If the storage drum is switched on and off based on light barrier detection, then cable over-unwinding is prevented, but higher tensile forces are generated during cable pulling

Engineering Contradiction:
Improvecable unwinding controlVSAvoidtensile force on cable
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

Instead of binary on/off control based on light barrier detection, the system uses continuous speed adjustment of the storage drum. The control unit modulates drum rotation speed dynamically to match cable pulling speed, preventing over-unwinding while maintaining constant cable tension and avoiding high tensile force spikes

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sensor-based feedback system provides continuous speed information to the control unit, enabling proportional control of the drum drive. This replaces the abrupt switch-on/switch-off control with smooth, continuous speed regulation that prevents both over-unwinding and excessive tensile forces

Inventive Principle:
Principle #23Feedback

3Reliability

If the inspection camera stops, then cable feeding halts, but unnecessary excess cable length is unwound from the storage drum

Engineering Contradiction:
Improvecable feeding controlVSAvoidexcess cable length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The storage drum speed is dynamically adjusted based on real-time cable speed detection. When the inspection camera stops and cable movement ceases, the control unit automatically reduces drum rotation speed to match, preventing unnecessary cable unwinding while ensuring smooth cable feeding during movement

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The feedback control system continuously monitors cable speed and adjusts drum drive accordingly. When cable speed drops to zero (camera stopped), the system automatically reduces drum speed to prevent excess cable unwinding, eliminating the need for manual intervention or fixed on/off control thresholds

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2857339B1Cable storage device
Publication Date: 2017.05.24 KUMMERT BERNHARD
  • EP2857339B1 patent drawingFigure 1
  • EP2857339B1 patent drawingFigure 2
  • EP2857339B1 patent drawingFigure 3

AI summary

The invention relates to a cable storage device (01) for receiving and dispensing a cable (02), in particular a data cable, at the end of which an inspection camera (04) can be arranged, wherein signals to and from the inspection camera (04) can be transmitted via the cable (02), comprising a rotatably mounted storage drum (07) on which the cable (02) can be wound, a drum drive (08) which can drive the storage drum (07) in the unwinding and winding directions, a control device (09) for controlling the drum drive (08), a cable guide (11) and a cable buffer (12) arranged between the cable guide (11) and the storage drum (07), which can accommodate a variable buffered cable length (13), wherein a measuring device connected to the control device (09) can determine the fill level of the cable buffer (12).wherein the control device (09) can automatically control the drum drive (08) depending on the filling state in the unwinding and winding direction.