Passive Zero-Backlash Camera Mast Locking Joint

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Solution Overview

Problem

Existing camera mast locking mechanisms for vehicles often suffer from backlash and require user intervention or additional components, leading to increased complexity, cost, and reduced structural integrity during dynamic loads.

Innovation Solution

A zero-backlash locking assembly using a mast stop member, pawl member, shaft member, and torsion spring that passively locks the camera mast in an upright position without user interaction, ensuring stability and rigidity by preventing rotation in one direction and allowing easy manual release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If typical latches and locking mechanisms are used to lock the mast in place, then the mast can be secured in an upright position, but backlash occurs in the joint which degrades structural integrity

Engineering Contradiction:
Improvestructural integrityVSAvoidcomplexity of locking mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the complex electro-mechanical locking components from the system and replaces them with a simplified passive mechanical locking mechanism. The locking function is achieved through a pawl member that engages with a ratchet on the mast, eliminating the need for motors, sensors, and control systems while preventing backlash through the inherent mechanical engagement geometry.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The locking mechanism automatically engages and locks the mast in the upright position through passive mechanical interaction between the pawl member and ratchet. The system self-locks without requiring user intervention or external power sources, while the spring-loaded pawl maintains constant engagement to eliminate backlash during dynamic loads.

Inventive Principle:
Principle #25Self-service

2Reliability

If active locking mechanisms are used to secure the mast, then the mast can be locked in place, but user intervention or additional components are required which adds cost and complexity

Engineering Contradiction:
Improvelocking reliabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes all electro-mechanical locking components (motors, actuators, sensors, control systems) from the mast assembly, replacing them with a simple passive mechanical locking system consisting of a pawl member, ratchet, and spring, thereby reducing component count and system cost while maintaining locking reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The locking mechanism performs the locking function automatically through passive mechanical engagement between the pawl and ratchet, eliminating the need for user intervention or external power sources. The spring-loaded pawl automatically engages the ratchet teeth to maintain the mast in the locked upright position.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If conventional locking mechanisms are used, then the mast can be secured, but the joint gaps under dynamic load due to backlash

Engineering Contradiction:
Improvejoint stabilityVSAvoidease of deployment
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent employs asymmetric engagement geometry between the pawl member and ratchet teeth, where the pawl engages the ratchet in one direction to prevent backlash and maintain joint stability under dynamic loads, while allowing easy manual release by actuating the pawl in the opposite direction to disengage from the ratchet teeth.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The locking mechanism automatically maintains joint stability through passive mechanical engagement, eliminating backlash under dynamic loads without requiring active control or user intervention. The spring-loaded pawl continuously maintains engagement with the ratchet to prevent joint gaps during operation.

Inventive Principle:
Principle #25Self-service

4Reliability

If additional electro-mechanical devices are added to lock the mast, then the locking function is achieved, but the natural frequency of the mast structure decreases

Engineering Contradiction:
Improvelocking securityVSAvoidnatural frequency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent removes heavy electro-mechanical locking devices (motors, actuators, control systems) from the mast assembly and replaces them with a lightweight passive mechanical locking system consisting of a pawl member, ratchet, and spring, thereby reducing overall mass and increasing the natural frequency of the mast structure while maintaining secure locking functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The lightweight passive mechanical locking system achieves secure locking through automatic engagement of the pawl member with the ratchet, eliminating the need for heavy electro-mechanical components. This reduction in mass increases the natural frequency of the mast structure, improving its dynamic response characteristics.

Inventive Principle:
Principle #25Self-service

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 solution provides a secure, stable, and easily deployable camera support structure with higher natural frequency, eliminating backlash and the need for additional components, thus enhancing the structural integrity and usability of the camera mast system.

Implementation Method 1

The torsion spring secures the first end of the pawl member against the surface of the elongated mast in a deployed state with zero backlash

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3635483B1Releasable zero backlash passive locking mechanism for a vehicle mounted rotary camera mast
Publication Date: 2023.12.06 GOOGLE LLC
  • EP3635483B1 patent drawingFigure 1A
  • EP3635483B1 patent drawingFigure 1B
  • EP3635483B1 patent drawingFigure 2A

AI summary

A rotary locking joint that has zero backlash is provided to secure a camera mast mounted on a vehicle in a deployed position. The joint is passive to lock while being easily releasable. The joint prevents rotation of the mast in one direction, with a hard stop element that prevents further rotation of the mast in the opposite direction. The locking joint includes a pawl member configured to rotate about a pawl rotation axis. The pawl member is maintained in place in the locked position via a torsion spring to ensure contact with a base portion of the mast. To release the joint, the pawl member is rotated in the opposite direction to remove a geometry interference condition. A sensor is arranged to detect whether the pawl member is in an unlocked position relative to the mast.