Compact Spring Load Test Stand for Actuating Systems

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Solution Overview

Problem

Existing load test benches for missile systems are costly and inflexible, requiring large climatic chambers and separate devices for multi-axis vibration tests, and struggle to apply defined lateral forces efficiently.

Innovation Solution

A compact, passive load test stand with a spring mechanism and adjustable flange, allowing independent alignment along multiple axes and application of defined lateral forces, coupled with a measuring system for precise measurements and inertial bodies for realistic simulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If almost linear torsion springs are used to cover a sufficiently large actuating angle range, then the verification range is improved, but the minimum length of the torsion bars increases leading to very large climatic chambers and structural-mechanical difficulties

Engineering Contradiction:
Improveactuating angle rangeVSAvoidclimatic chamber size
Core Design Contradiction:
Adaptability or versatilityVSVolume of stationary object

Solution Approach 1:

The patent divides the single large torsion bar into multiple smaller torsion bars (first, second, third torsion bars) arranged in parallel. Each torsion bar has a shorter length and can be accommodated in smaller climatic chambers, while collectively they provide the same or greater actuating angle range through their combined torsional capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The multiple torsion bars are arranged in a compact parallel configuration where they share common mounting points (first and second connection points) on the frame and the common axis. This nested-like arrangement allows the torsion bars to be closely packed, minimizing the overall volume required while maintaining the functional range.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Volume of stationary object

If different offset angles when flange-mounting the torsion spring are used to reduce the required adjustment range, then the spring size is reduced, but re-clamping is required leading to multiplication of temperature cycles in climatic chambers

Engineering Contradiction:
Improvespring sizeVSAvoidre-clamping effort
Core Design Contradiction:
Volume of stationary objectVSLoss of time

Solution Approach 1:

The patent introduces adjustable positioning elements that allow the connection points of the torsion bars to be dynamically repositioned along the frame structure. This adjustability enables the system to accommodate different test requirements without requiring physical re-clamping of the torsion bars themselves, thus reducing time loss while maintaining compact spring sizes.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The frame structure is designed with multiple predefined mounting positions and adjustable mechanisms that allow the same torsion bar assembly to be configured for different actuating angle ranges and test specifications. This multi-functional design eliminates the need for re-clamping when changing test parameters, as the adjustable positions provide universal adaptability.

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

3Adaptability or versatility

If large torsion bars are used to cover large actuating angle ranges, then the actuating angle verification is improved, but the load test bench requires enormously large and powerful climatic chambers unfavorable for three-axis clampability

Engineering Contradiction:
Improveactuating angle rangeVSAvoidstructural dimensions
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the load path by using multiple shorter torsion bars instead of one large torsion bar. Each bar carries a portion of the total torque, and their parallel arrangement provides the cumulative actuating angle range. This segmentation reduces the individual bar lengths and allows compact arrangement, simplifying the overall structural dimensions and improving three-axis clampability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-dimensional (one large bar) to a multi-dimensional arrangement by positioning multiple torsion bars in parallel along different spatial orientations. This dimensional change allows the system to achieve the required actuating angle range through spatial distribution rather than increasing the length of individual components, thereby reducing structural complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Ease of manufacture

If separate test devices are used for vibration tests, then the function test can be carried out separately, but only separate function test without application of torsional moments is possible

Engineering Contradiction:
Improveseparate test capabilityVSAvoidcombined testing capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent merges the function test capability and vibration test capability into a single integrated load test bench. The frame structure is designed to be rigid enough to serve as a vibration test platform while the torsion bar mechanism provides the necessary torsional moments for function testing. This combination allows both types of tests to be performed on the same apparatus, either separately or simultaneously, eliminating the need for separate test devices.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The load test bench is designed with universal functionality to perform multiple test types: function testing with torsional moments, vibration testing, and combined testing. The frame and mounting structure are engineered to accommodate both static torsion loading and dynamic vibration excitation, making the device adaptable to various test requirements without needing separate specialized equipment.

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

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

Enables quick, reliable, and flexible testing of actuating systems with reduced re-clamping efforts and temperature compensation, accommodating multi-axis vibration tests within compact climatic chambers.

Implementation Method 1

A passive load test stand 2 is described, in particular for simulating load cycles. The spring mechanism stores energy when deformed and releases it during recoil, creating realistic load cycles without active control systems.

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The spring mechanism has a preferred symmetrical arrangement of at least four spring elements and includes frame points connecting to the frame and pivot points connecting to the flange, generating restoring forces that simulate realistic load profiles on the output shaft.

Methodology Applied
Scientific EffectHooke's Law: Hooke's Law

Data Source

PatentEP2767814B1Load test stand for control systems with an output shaft
Publication Date: 2019.08.28 MBDA DEUTSCHIAND GMBH
  • EP2767814B1 patent drawingFigure 1
  • EP2767814B1 patent drawingFigure 2
  • EP2767814B1 patent drawingFigure 3

AI summary

The stand (1) has a spring mechanism mounted on a frame (13) and comprising four spring elements, frame points connecting the spring mechanism and the frame, and articulation points connecting the spring mechanism and a flange. The flange is coupleable to an output shaft of a servo system (4) to be tested by an adapter. The frame points are mounted in a substructure. The substructure and the spring mechanism form an adjustable or calibratable independent module (7), where the module is arranged on the frame by a universal interface.