Drone Anchoring Harpoon with Bistable Actuator

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Solution Overview

Problem

The adaptation of existing anchoring harpoons for helicopters to rotary-wing drones has been unsuccessful due to issues such as size, weight, and maintenance concerns.

Innovation Solution

A modified anchoring harpoon system featuring a jack with a piston and a hooking harpoon head, utilizing a bistable actuator with a rotary mechanical lock and a consumable CO2 gas source for pressurized fluid supply, allowing for efficient deployment and anchoring with reduced length and improved maintenance, incorporating a telescopic cylinder and a helical spring for secure anchoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing anchoring harpoons for helicopters are adapted to rotary-wing drones, then the anchoring function can be provided, but the size and weight become too large for drone applications

Engineering Contradiction:
Improveanchoring functionVSAvoidharpoon weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The harpoon system employs nested telescopic cylinders where the second cylinder is received within the first cylinder. The piston rod extends from the second cylinder, creating a compact nested structure that reduces overall size and weight while maintaining the anchoring function. This nested configuration allows the harpoon to be stored in a compact form on the drone and deployed when needed.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The anchoring harpoon is divided into separate functional segments: the first cylinder, the second cylinder, the piston rod, and the harpoon head with retaining fingers. This segmentation allows each component to be optimized independently for weight and function, and enables the overall system to be more compact compared to a monolithic design.

Inventive Principle:
Principle #1Segmentation

2Reliability

If existing anchoring harpoons for helicopters are adapted to rotary-wing drones, then the anchoring function can be provided, but the harpoon size becomes too large for drone integration

Engineering Contradiction:
Improveanchoring functionVSAvoidharpoon length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The telescopic cylinder arrangement with the second cylinder nested within the first cylinder significantly reduces the extended length of the harpoon when in its stowed position on the drone. When deployed, the cylinders extend to provide the necessary anchoring length, thus achieving both compact storage and functional deployment.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If traditional harpoon systems are used on drones, then anchoring capability is achieved, but maintenance becomes complex and difficult

Engineering Contradiction:
Improveanchoring capabilityVSAvoidmaintenance complexity
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The bistable actuator automatically maintains the retaining fingers in either the retracted or extended position without requiring continuous external control or complex maintenance. The mechanical self-locking feature of the bistable actuator reduces the need for active maintenance and simplifies the overall system, making it more suitable for drone applications where maintenance access may be limited.

Inventive Principle:
Principle #25Self-service

4Weight of moving object

If a compact harpoon system is designed for drones, then size and weight are reduced, but the anchoring reliability may be compromised

Engineering Contradiction:
Improveharpoon weightVSAvoidanchoring reliability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The nested telescopic cylinder design maintains full anchoring functionality when deployed, as the cylinders extend to provide the necessary length and the harpoon head with retaining fingers engages the anchoring grid. The compact nested form only affects the stowed size, not the deployed performance, thus maintaining reliability while reducing weight.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The control system for the retaining fingers has been extracted and simplified through the bistable actuator mechanism, which provides reliable positioning without requiring complex continuous control systems. This extraction of the control function to a simple bistable mechanism maintains reliability while reducing overall system complexity and weight.

Inventive Principle:
Principle #2Taking out (Extraction)

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 system enables successful automatic landing and take-off of rotary-wing drones by providing a compact, efficient, and reliable anchoring mechanism that adapts to the specific requirements of drones, overcoming previous integration challenges.

Implementation Method 1

the pressurized fluid source comprises a consumable gas cartridge, the gas is CO2

Methodology Applied
Scientific EffectPressurized gas: Pressure Increase

Implementation Method 2

a helical return and pressing spring is interposed between this end of the cylinder and the harpoon head

Methodology Applied
Scientific EffectElastic potential energy: Spring

Implementation Method 3

the control means comprise means forming a solenoid valve controlled on opening and closing to supply the means in the form of a cylinder

Methodology Applied
Scientific EffectElectromagnetic actuation: Solenoid

Data Source

PatentEP2414238B1Anchoring harpoon intended in particular for an aircraft and anchoring system including one such harpoon
Publication Date: 2015.10.14 DCNS SA
  • EP2414238B1 patent drawingFigure 1
  • EP2414238B1 patent drawingFigure 2
  • EP2414238B1 patent drawingFigure 3

AI summary

The invention relates to an anchoring harpoon intended in particular for an aircraft, capable of cooperating with an anchoring grate of a platform, comprising jack means including cylinder means containing mobile piston means provided with a rod that extends beyond the cylinder means, the free end of which includes a harpoon head (7) that is hooked in the grate and comprises retaining fingers (8, 13, 14) that can be moved between a retracted position and an active position by control means (9). The invention is characterised in that the means (9) for controlling the movements of the fingers comprise a control piston (18) which can slide inside the rod of the jack and which is associated with a bistable actuator (19) of the fingers, capable of moving between a retracted position and an active position in which the fingers are deployed with the application of successive pressure pulses in the jack means.