Towing Winch Deflection Pulley Tensile Force Control

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Solution Overview

Problem

Current towing winches for hang gliders and paragliders lack efficient and reliable means to detect tensile force and control the towing process, particularly in varying conditions, leading to potential safety risks and inefficiencies.

Innovation Solution

A towing winch with a deflection pulley system and sensor setup that allows for precise detection of tensile force without relative displacement, combined with a control system using a microcontroller and sensors for real-time data processing, enabling computer-aided control and reliable measurement of cable length and angle of inclination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a deflection pulley system is used to guide the tow cable, then the towing operation can be performed safely with the pilot in the field of vision, but the cable length measurement becomes complex due to the need to account for the deflected path

Engineering Contradiction:
Improvesafety of towing operationVSAvoidcomplexity of cable length measurement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A cable length marker is introduced as an intermediary element on the tow cable. This marker serves as a reference point that simplifies the measurement system - when the marker passes a fixed reference point at the towing winch, the cable length can be directly determined without complex calculations of the deflected cable path through the pulley system

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanical complexity of tracking the deflected cable path through the pulley system is replaced by an optical/electronic detection system. A sensor (such as an optical sensor or marker detection system) detects when the cable length marker passes the reference point, providing direct electronic signal for cable length measurement without mechanical measurement components

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If the sensor detects contact force of the lever arm against the support surface, then the tensile force can be measured without relative displacement, but the sensor must withstand high contact forces while maintaining measurement precision

Engineering Contradiction:
Improveprecision of tensile force detectionVSAvoidreliability of sensor under high force
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The lever arm is pre-loaded against the support surface with a spring element before towing begins. This pre-loading ensures that the sensor detects only changes in force (the tensile force variations during towing) rather than the absolute high force values, protecting the sensor from damage while maintaining measurement precision for force variations

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The measurement parameter is changed from absolute force measurement to differential force measurement. By pre-loading the lever arm and sensor, the system measures only the variations in tensile force (deltas) rather than the absolute high force values, extending sensor life while maintaining measurement accuracy for force changes

Inventive Principle:
Principle #35Parameter changes

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 solution provides a safe and efficient towing operation by accurately measuring and controlling the tensile force and cable length, reducing the risk of accidents and ensuring consistent takeoff conditions.

Implementation Method 1

a sensor (6) serving to detect the contact force (FA) of the lever arm (5) against the support surface (7)

Methodology Applied
Scientific EffectForce detection: Force

Implementation Method 2

The lever arm (5) has an actuating means (8) on which a force can be exerted by means of which the lever arm (5) can be subjected to an adjustable, in particular negative, prestressing force (FV) against the support surface (7)

Methodology Applied
Scientific EffectElastic force: Spring

Data Source

PatentEP2962980B1Towing winch for air sports devices, and method for operating such a towing winch
Publication Date: 2017.09.20 GRUNWALD SIEGFRIED W
  • EP2962980B1 patent drawingFigure 1
  • EP2962980B1 patent drawingFigure 2
  • EP2962980B1 patent drawingFigure 3

AI summary

The invention relates to a tow winch designed as a launching device for hang gliders, paragliders, or similar unpowered air sports equipment, comprising at least one cable drum (18). The tow winch has a cable guide (2, 13) with a deflection pulley (3) through which the tow rope (1) is guided and deflected. The deflection pulley (3) is held on a support (5) pivotable about a pivot point (4) and rests against a stationary support surface (7) at a point opposite the deflection pulley (3). During the launch phase of the air sports equipment, the tow rope (1), which has been previously unwound in a manner known per se and laid out in as direct a connection as possible with the air sports equipment or the pilot, is wound up, thereby realizing the launch phase.For this purpose, the towing winch is equipped with a control device for detecting the tensile force of a tow rope (1) by means of various sensors (6), so that a constant tensile force of the tow rope (1) can be set based on the measured values.