EMAX Lawnmower Improvements for 2013

Sales Season

Paul Hodgson

Design Engineer

Project Objectives

• This project was initiated to address the various quality and performance concerns related to the EMAX lawnmowers that have arisen during their first season in the marketplace

• From the analysis of these concerns it has been possible to identify the contributory faults and devise solutions. These solutions and implementation details are illustrated in the following slides

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EMAX32

1. Switchbox / Handle

Improvements

2. Transmission Improvements (motor, belt, housings)

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1a. Additional screw bosses to improve

switch location

Issue: Intermittent switching or no power. Lock button releases whilst in use

Status: Implemented as Type 2 on all SKUs, week 34

1c. Lock button / lever interface redesigned to

ensure positive engagement and correct

actuation of switch

1d. Additional ribs added in housing to retain lock button

when actuated

1e. Uprated lever sping to ensure

lever fully retreats upon release

1b. Lever actuator thickened to

increase rigidity

1. EMAX32 Switchbox / Handle Improvements

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1f. In redesigning lock button / actuator interface, switching

postion has been moved earlier in stroke. More over travel

Issue: Switching point to close to handle, user needs to grip lever tightly and constantly to avoid interuptions in power supply

Status: Implemented as Type 2 on all SKUs, week 34

1. EMAX32 Switchbox / Handle Improvements

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1g. Dimensional changes to screw bosses and

supporting ribs to secure switchboxes to handle and limit rotational movement

Issue: Switchbox not secured to handle, even though screws are fully engaged. Can cause switching problems and suggests low quality

Status: Implemented as Type 2 on all SKUs, week 34

1. EMAX32 Switchbox / Handle Improvements

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Issue: Early transmission failures, snapped armature shafts, melting of bearing housings & belts cutting through deck

Status: Target implemetation week 44

2. EMAX32 Transmission Improvements

2a. Material change on main structural components to BMC. This gives

improvements in terms of dimensional and temperature stability. Fundamentally, it is a more rigid material which will allow a lower

belt tension, thus reducing stress on all connected components within the

transmission

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Issue: Early transmission failures, snapped armature shafts, melting of bearing housings & belts cutting through deck

Status: Program of testing underway, target implementation week 40

2. EMAX32 Transmission Improvements

2c. Belt retenion lip increased on gear

wheel

2b. Extra grinding operation added to manaufacture of

armature shaft to ensure that assembled pinion meets run-

out specification

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EMAX34 / 38

3. Switchbox / Handle

Improvements

4. Transmission Improvements (motor, belt, housings)

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Issue: Intermittent switching or no power. Lock button releases whilst in use

Status: Implemented as Type 2 on all SKUs, week 34

3. EMAX34 / 38 Switchbox / Handle Improvements

3. All switchbox changes are the same as described on EMAX32

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Issue: Early transmission failures, snapped armature shafts & belts cutting through deck

Status: Program of testing underway, target implementation week 40

4. EMAX34 / 38 Transmission Improvements

4a. Belt retenion lip increased on gear

wheel

4b. Extra grinding operation added to manaufacture of

armature shaft to ensure that assembled pinion meets run-

out specification

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EMAX42

5. Switchbox / Handle

Improvements

6. Transmission Improvements (motor, belt, housings)

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Issue: Intermittent switching or no power. Lock button releases whilst in use

Status:Implemented as Type 2 on all SKUs, week 34. Pivot location improvements week 40

5b. Pivot support location improved to ensure positive

switching over complete length of bale bar

5. EMAX42 Switchbox / Handle Improvements

5a. Internal modifications as described on EMAX

32/34/38

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Issue: Early transmission failures, snapped armature shafts & belts cutting through deck

Status: Program of testing underway, target implementation week 40

6. EMAX42 Transmission Improvements

6a. Belt retenion lip increased on gear

wheel

6b. Extra grinding operation added to manaufacture of

armature shaft to ensure that assembled pinion meets run-

out specification

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Standardise clip dimensions on EMAX 34

& 38 grassboxes to match those on EMAX42

EMAX 34 / 38 / 42 Grassboxes

EMAX 34 & 38 grassbox clips will be modified when production schedule allows access to mould tools.

There is no functional problem with EMAX 34 & 38 grassboxes as they are currently being produced, the modification is to standardise dimensions across all SKUs

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Implementation Summary

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Issue Affected Models Solution Proposed Implementation

Intermittent switching or no power. Lock button releases whilst in use

EMAX 32/34/38/42Redesign of internal

mechanismWeek 34

Switching point too close to handle

EMAX 32/34/38/42Redesign of internal

mechanismWeek34

Switchbox loose on handle

EMAX 32/34/38/42Modifications to screw bosses and supporting

ribsWeek 34

Snapped armatures, melted bearing housings

& belts cutting decksEMAX 32

Change material of transmission bracket

and bearing housings to BMC type material

Week 44

Snapped armatures & belts cutting decks

EMAX 32/34/38/42

Extended belt retaining lip & armature shafts to

have ground pinion mounting surface.

Week 40

Bale arm pivot can become dislocated in

housingEMAX 42

Increase are of location in pivot housing

Week 40