Articulated Lawn Mower Frame Locking Mechanism

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Solution Overview

Problem

Existing lawn mower adjustment systems are complex and impractical for rapid changes, requiring significant effort from operators and involving intricate construction.

Innovation Solution

A compact locking device for an articulated frame with a knob-activated mechanism using axial compression springs and offset cylindrical guides to facilitate easy adjustment and locking of the lawn mower's arrangement, allowing minimal effort operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple locking system is used, then the device complexity is reduced, but the reliability of locking may be compromised

Engineering Contradiction:
Improvelocking system complexityVSAvoidlocking reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The locking system uses self-contained elements (locking lever, springs, cam surfaces) that automatically engage and disengage without requiring external actuators or complex control mechanisms. The springs provide automatic return to locked position, and the cam surfaces guide the locking lever through its motion path, creating a self-sufficient locking mechanism.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention extracts the essential locking function from complex multi-component systems and implements it through a single integrated locking lever that interacts with simplified cam surfaces on the rods. This removes unnecessary intermediate components while maintaining the core locking capability.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If rapid adjustment is enabled, then the ease of operation is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveadjustment speedVSAvoidcam surface precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The locking system transitions from static fixed positions to dynamic adjustable positions through the movable locking lever. The lever can quickly shift between different locking positions along the cam surfaces, enabling rapid adjustment while the cam surfaces provide the necessary guidance and positioning.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The cam surfaces are pre-formed with specific geometric profiles that guide the locking lever through predetermined motion paths. This preliminary preparation of the cam geometry allows the locking lever to automatically achieve correct positioning without requiring high-precision real-time control during operation.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If minimal operator effort is required, then the ease of operation is improved, but the force generation capability may be reduced

Engineering Contradiction:
Improveoperator effortVSAvoidlocking force
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The springs are pre-compressed to store potential energy that counteracts the forces required to maintain the locking engagement. When the locking lever is moved into position, the springs provide a counterbalancing force that reduces the effort needed from the operator while ensuring sufficient locking force is generated through the cam surface interaction.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The cam surfaces utilize curved geometric profiles that transform the operator's small input motion into larger force multiplication through mechanical advantage. The curved surfaces guide the locking lever through a path that maximizes force generation during engagement while minimizing the effort required to initiate and complete the locking action.

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

Enables simple, efficient adjustment and locking of the lawn mower's frame and handlebar inclination with minimal operator effort, ensuring optimal cutting and grass ejection conditions.

Implementation Method 1

a locking device (30) capable of locking said pair of connection articulations in a locked frame position, comprising a casing (31), a pair of lock pins (41a, 41b) slidable along cylindrical seats (32a, 32b) made in the casing, coaxial to each other, connected, respectively, to a first rod (42), sliding along a first cylindrical guide (33), and to a second rod (43), sliding along a second cylindrical guide (34), coaxial to the cylindrical guide (33), and parallel and offset with respect to the cylindrical guide (39)

Methodology Applied
Scientific EffectElastic spring force: Spring

Data Source

PatentEP2684439B1Machine for mowing lawns and gardens with an adjustable articulated frame
Publication Date: 2016.06.01 GGP ITAL
  • EP2684439B1 patent drawingFigure 1~2
  • EP2684439B1 patent drawingFigure 3~4
  • EP2684439B1 patent drawingFigure 5

AI summary

A lawn mower machine (1) comprising an articulated frame adjustable by means of a locking device (30) operating on a pair of rods (20) hinged with respect to a body (10) by means of lock plates (22) is described. Said locking device (30) comprises a pair of lock pins (41a, 41b) engageable with said pair of rods (20) and integral with respective further seats (42, 43) reversibly and simultaneously actuatable by means of a disc (51). (Fig. 5).