Robot Mower Charging Contact Geometry for Misalignment Tolerance

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Solution Overview

Problem

Existing robot lawn mower charging systems face issues with vertical and horizontal misalignments due to debris and grass cuttings, which can prevent proper engagement between the mower and the charging station, and exposed electrical pins are vulnerable to the elements.

Innovation Solution

A contact pin and socket arrangement with resilient upright side surfaces, where the contact pin engages with guide surfaces to correct horizontal misalignment and the contact socket accommodates vertical misalignment, ensuring robust and safe electrical contact, with the guide surfaces and pin support design allowing for self-alignment and self-cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If exposed electrical pins are used for charging connection, then the charging system is simple, but the electrical components are vulnerable to environmental elements

Engineering Contradiction:
Improvecharging system structureVSAvoidenvironmental exposure
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The contact pin is nested within a protective housing that contains the contact socket. The housing encloses the electrical connection components, protecting them from environmental elements while maintaining the charging function. The contact pin extends from the mower into the protected socket area only during engagement.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Manufacturing precision

If upright guide surfaces are provided on the base plate, then horizontal misalignment is corrected, but the lawnmower may not move properly into engagement if displaced too far

Engineering Contradiction:
Improvehorizontal alignmentVSAvoidengagement movement
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The guide surfaces extend beyond the vertical plane to form inclined surfaces that guide the contact pin horizontally into alignment. This three-dimensional guiding structure allows the mower to approach from various positions and automatically corrects horizontal misalignment through the inclined geometry, eliminating the need for restrictive side guide plates.

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

3Adaptability or versatility

If the contact socket depth is increased to accommodate vertical misalignment, then vertical misalignment is tolerated, but the device complexity increases

Engineering Contradiction:
Improvevertical misalignment toleranceVSAvoidcontact socket structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The contact socket incorporates a conical or tapered recess that guides the contact pin into proper engagement. This curved geometry naturally accommodates vertical misalignment by allowing the pin to enter at varying depths and angles, while the resilient contact surfaces ensure reliable electrical connection without requiring excessive socket depth or complex adjustment mechanisms.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 solution allows for reliable engagement and charging of the robot lawn mower by accommodating height and horizontal misalignments, protecting electrical components from the environment, and ensuring a safe and robust electrical connection.

Implementation Method 1

the two contact surfaces being resiliently urged together by resilient means

Methodology Applied
Scientific EffectResilient means (elasticity): Elasticity

Data Source

PatentEP2656718B1A ground care apparatus and a charging station apparatus therefor
Publication Date: 2018.07.04 ROBERT BOSCH GMBH
  • EP2656718B1 patent drawingFigure 1
  • EP2656718B1 patent drawingFigure 2
  • EP2656718B1 patent drawingFigure 3

AI summary

A ground care apparatus such as a robot lawnmower and a charging station apparatus. The charging station mounts a pair of substantially upright opposed guide surfaces, inner ends of which are separated by a contact socket apparatus including a contact socket and outer ends being further apart than the inner ends., The lawn mower mounts a contact pin which extends generally horizontally from said apparatus, and the lawn mower and charging station are adapted so that they move or are moved to engage with one another and engage said contact pin in said contact socket, and if the two apparatuses are misaligned horizontally, said contact pin engages a relevant guide surface so that the contact pin and contact socket are relatively guided into engagement