Non-Circular Tapered HDRM Interface for Spacecraft Torsion Loads

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Solution Overview

Problem

Conventional cup and cone HDRM interfaces lack rotational support, leading to structural damage in spacecrafts with low internal stability due to high torsional loads, and are difficult to manufacture with play-free connections.

Innovation Solution

A HDRM interface with a tapered projection and matching recess having non-circular surfaces, forming a three-sided pyramid shape to transfer both torsion and shear loads while ensuring a play-free connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional cup and cone HDRM interfaces are used, then simplified mounting and assembly is enabled with shear load transfer capability, but rotational support is lacking causing structural damage in spacecrafts with low internal stability due to high torsional loads

Engineering Contradiction:
Improveshear load transfer capabilityVSAvoidrotational support
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The invention replaces the circular symmetric cup and cone interface with an asymmetric three-sided pyramid-shaped interface. The pyramid shape has three lateral sides that are not rotationally symmetric, providing both shear load transfer capability and rotational support. The asymmetric geometry creates inherent rotational stiffness while maintaining the form-locking mechanism needed for robust connection.

Inventive Principle:
Principle #4Asymmetry

2Ease of manufacture

If conventional cup and cone HDRM interfaces are used, then manufacturing is simplified, but play-free connection is difficult to achieve

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidplay-free connection
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention applies curved tapered surfaces to the pyramid-shaped connector parts. The lateral sides of the pyramid are formed with tapered curvature that enables self-aligning and form-locking connection. This curved geometry provides play-free connection by creating continuous contact surfaces that accommodate minor manufacturing tolerances while maintaining rigid connection.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Device complexity

If conventional cup and cone HDRM interfaces are used, then the design is simple, but torsional load management is insufficient leading to structural damage

Engineering Contradiction:
Improveinterface design simplicityVSAvoidtorsional load management
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The invention transitions from a two-dimensional circular interface to a three-dimensional pyramid-shaped interface with lateral sides extending in multiple directions. This dimensional change from circular symmetry to polyhedral geometry provides inherent torsional resistance while maintaining relatively simple manufacturing processes for the connector parts.

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

Data Source

PatentEP4180339B1A separable clamped HDRM interface for managing torsion loads
Publication Date: 2025.12.03 RUAG SPACE
  • EP4180339B1 patent drawingFigure 1~3
  • EP4180339B1 patent drawingFigure 4~5
  • EP4180339B1 patent drawingFigure 6A~6B

AI summary

A Hold Down Release Mechanism, HDRM, interface (8) for attachment of a spacecraft (3) to an adjacent structure of a launch vehicle (1) or of another spacecraft (54), wherein the HDRM interface (8) is configured for forming part of a single-point or multipoint releasable attachment of the spacecraft (3) to said adjacent structure. The HDRM interface (8) comprises a first connector part (11) and a second connector part (12), wherein one of the first and second connector parts (11, 12) is configured to be fastened to said adjacent structure, and the other of the first and second connector parts (11, 12) is configured to be fastened to the spacecraft (3); wherein the first connector part (11) has a tapered projection (19) with a non-circular external surface; wherein the second connector part (12) has a matching formed tapered recess (20) with a non-circular interior surface configured for form-lockingly receiving the tapered projection (19), for enabling transfer of at least torsion load and shear load between the first and second connector parts (11, 12), when the tapered projection (19) is inserted in the tapered recess (20) and the first and second connector parts (11, 12) are pressed together; and wherein both the tapered projection (19) of the first connector part (11) and the tapered recess (20) of the second connector part (12) have a central through-hole (22, 23) for receiving a release bolt (47) configured to clamp the first and second connector parts (11, 12) together.