Split Adjustment Nut Assembly for Reliable Robotic Mower Height Control

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Solution Overview

Problem

Existing height adjustment devices face challenges in providing a reliable screw-to-nut connection and efficient assembly process.

Innovation Solution

The height adjustment device features an adjustment nut with a first part and a second part that enclose the adjustment screw, eliminating the need for the screw to be inserted from one end during assembly and eliminating the requirement for a resilient member to maintain thread engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If an open nut is used with a biasing element to keep the screw in engagement, then assembly is quicker and more effective, but the screw-to-nut connection reliability is compromised

Engineering Contradiction:

Improveassembly speedVSAvoidscrew-to-nut connection reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The adjustment nut is divided into a first part and a second part that can be assembled separately around the adjustment screw. The first part engages with the screw threads while the second part closes the nut, eliminating the need for insertion from one end and removing the requirement for biasing elements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of inserting the screw into the nut from one end as in conventional designs, the nut is assembled by bringing the first and second parts together around the mid-portion of the screw, effectively reversing the traditional assembly sequence and approach.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If the screw is inserted from one end into the nut during assembly, then the connection can be maintained, but the assembly process becomes more complex and time-consuming

Engineering Contradiction:

Improvethread engagement maintenanceVSAvoidassembly process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The nut is segmented into two parts that enclose the screw from opposite directions, allowing assembly without inserting the screw from one end. This segmentation simplifies the assembly process while maintaining reliable thread engagement through the combined structure of both parts.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first and second parts of the nut are designed to nest together around the adjustment screw, with the second part fitting over or engaging with the first part to complete the enclosure of the screw, creating a compact and reliable assembly.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS12232443B2Height adjustment device and robotic mower comprising a height adjustment device

Publication Date: 2025.02.25 HUSQVARNA AB

AI summary

A height adjustment device may include a height adjustment screw having outer threads and being oriented substantially vertically and arranged rotatably in relation to a chassis, and an adjustment nut connected to a bracket and comprising inner threads for engagement with the threads of the adjustment screw, such that a rotary movement of the height adjustment screw results in a vertical linear movement of the bracket. The adjustment nut may include a first part and a second part which together enclose the adjustment screw, and the first part may be adapted to be attached to the second part. A robotic mower may include the height adjustment device.