Robot Joint Holding Brake with Magnet-Actuated Pawls

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Solution Overview

Problem

Existing robot joint holding brakes are either complex or lack safety features, particularly in preventing unintentional joint movement due to gravity or load, and fail to maintain a locked state without electrical energy.

Innovation Solution

A robot joint holding brake design featuring a brake housing with two pivotable pawls and a gear wheel, where only one pawl engages with the gear in the locked state, and a magnet holds the pawls outside the gear's gaps to maintain the brake in a released state, requiring motor activation to release, ensuring the joint is only unlocked when the motor can counteract loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a robot joint holding brake is designed to lock the joint without electrical power, then safety is improved, but the device complexity increases due to additional pawls and clamping mechanisms

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The brake mechanism is divided into two independent pawls (first and second pawls) that can operate independently. Each pawl has its own clamping device, allowing the system to achieve reliable locking in multiple states while maintaining modular simplicity in each individual component's design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The brake system dynamically transitions between different locking states: both pawls retracted (released state), first pawl engaged (first locked state), and second pawl engaged (second locked state). This dynamic multi-state capability provides enhanced safety and control without requiring complex additional components.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If a magnet is used to hold the pawl outside the gear gaps to maintain released state, then the joint can be unlocked when motor can counteract loads, but the use of energy increases due to magnet activation

Engineering Contradiction:
Improveease of operationVSAvoiduse of energy
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The magnet operates periodically rather than continuously - activated only when the joint needs to be released. The clamping devices maintain the pawls in their default positions without continuous energy input, and the magnet is engaged only temporarily to transition the pawls to the released position, reducing overall energy consumption.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The clamping devices are designed to automatically maintain the pawls in their engagement positions without requiring continuous active control or energy input. The mechanical spring-loaded clamping mechanism provides self-sustaining holding force, eliminating the need for continuous power consumption to maintain the locked state.

Inventive Principle:
Principle #25Self-service

3Device complexity

If only one pawl engages with the gear in locked state, then the structure is simplified, but the reliability of locking may be compromised

Engineering Contradiction:
ImprovestructureVSAvoidreliability of locking
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Each pawl is designed with specific local characteristics - the first pawl engages with gaps in a first rotational direction while the second pawl engages with gaps in a second rotational direction. This localized specialization allows each pawl to be optimally designed for its specific engagement direction, maintaining reliability while simplifying the overall structure by avoiding a single complex universal pawl design.

Inventive Principle:
Principle #3Local quality

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 design provides a structurally simple yet safe braking mechanism that locks the joint without electrical power and ensures the joint motor can handle torque loads, preventing unintended movement and ensuring operational safety by requiring active motor engagement to release the brake.

Implementation Method 1

a first magnet configured, during its activation, to hold the first pawl outside the gaps of the gear against the action of the first clamping device

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Data Source

PatentEP3419795B1Robot joint holding brake and robot comprising at least one such robot joint holding brake
Publication Date: 2019.11.27 KUKA DEUT GMBH
  • EP3419795B1 patent drawingFigure 1
  • EP3419795B1 patent drawingFigure 2~4
  • EP3419795B1 patent drawingFigure 5~8

AI summary

The invention relates to a robot joint holding brake (5) comprising a brake housing (6), a first (7.1) and a second pawl (7.2) pivotably mounted in the brake housing (6), with a first (8.1) and a second head section (8.2), a toothed wheel (10) rotatably mounted in the brake housing (6) with teeth (11) homogeneously distributed around the periphery, two respective adjacent teeth (11) thereof each defining a hole (12) in the toothed wheel (10), a first (9.1) and a second clamping device (9.2) designed to pivot the respective pawls (7.1, 7.2) against the toothed wheel (10) in such a way that the head section (8.1, 8.2) enters one of the holes (12), in a respective associated engaging position of rotation of the toothed wheel (10), in order to stop the robot joint holding brake (5), in addition to a magnet (14.1, 14.2) which is designed, when activated, to hold the pawls (7.1, 7.2) outside the holes (12) of the toothed wheel (10), against the action of the clamping devices (8.1, 8.2), in order to hold the robot joint holding brake (5) in the released state thereof. The invention further relates to an associated robot (1) comprising at least one such robot joint holding brake (5).