How to Convert your Washing Machine to Pedal Power 2 - Modifications

If you have just arrived at this project then you might want to to go back to Part One which can be found here, this will give you the steps needed to achieve your basic bicycle washer. The following shows the modifications I made to perfect the machine, making it easier to pedal and also giving us some 'spin cycle' too!

 At last year's Art & Garden Expo with our convivial host Daniel Renouf

Apart from the many other advantages of a pedal washing machine - saving on bills and energy consumption, fitness, fun, and time to read... everyone wants to do your laundry. Family, here on vacation, including the children, actually ask us to save up some washing! Even passing holiday-makers stop and ask to have a go pedalling. What could be better than to give them enjoyment and get your laundry done to boot!  

Modifications

The first arrangement had a 1:3.3 ratio from the bicycle pedal crank wheel to the gear on the motor shaft and between the motor and the drum pulley  a ratio of 14:1. Thus providing an overall gear ratio of: 4.2:1 i.e. just over 4 rotations of the pedal crank to get 1 revolution of the drum. No wonder 1 felt very little resistance when pedalling..

I thought that the gearing ratio should be at least 1:1 that is one revolution of the crank would produce one revolution of the machine drum. To this end, I disconnected the drive belt and screwed to the face of the large pulley wheel a pedal crank wheel from another bicycle. The drive chain was attached to this crank wheel, I had to increase the chain length by about 6-8 links to get it to fit.

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I had determined this to be the minimum ratio as I believed pedalling/drum speeds of  around 40-50 rpm allowed the contents to be sufficiently agitated for effective washing. At this speed, one could feel the load changing as the wet laundry was picked up in the drum by the paddles and then let fall back to the bottom of the drum due to gravity. This cadence was very easy to maintain even when the direction of pedalling was reversed. Unlike with the first highly-geared arrangement I had, the load provided a resistance to the pedalling which actually made it easier to do.

Surplus water removal (spin drying)

We’ve exhibited this machine on many occasions and the most frequent comment from spectators has been ‘let’s see you spin dry now!’. Modern washing machines have very high spin speeds (in the region of 1200 rpm or even greater). The need for these increasingly higher speeds is questionable as the additional amount of water extracted is relatively small. (See end of article for links to 'The Great Spin Debate'). Reading through it, it seems that so much, if not all, the escalating speeds are nothing more than sales gimmicks and may result in damage to the laundry.

Nevertheless, being able to remove some water prior to removal from the machine was desirable so I started by calculating what kind of drum speeds were necessary to keep the contents held against the drum wall for the complete cycle i.e. drum speed needed to overcome the acceleration due to gravity. Obviously this rotational speed varies with drum diameter and I've included at the end of this article a link to determine G forces.

With sufficient force holding the garments to the drum walls the water can escape through the holes in the drum. Higher rotational speed will obviously increase the rate of water loss.

For our drum of 46cm diameter, a calculated speed of 62.3 rpm would mean the contents would experience a force of 1g. Fast pedalling I could achieve a consistent speed of 100rpm producing a force of 2.6g but, if I dismounted and turned the pedal by hand I could achieve 170rpm producing a force of  7.4g. Such an action produced a significant  increase in the flow of water leaving the drum but it was not possible to maintain this speed for more than 60 seconds or so. On removing the garments there was still a considerable quantity of water in each item which could be extracted by wringing by hand.

Further modifications and improvements

Pump removal

After using the machine in this arrangement for 18 months or so I found a leak had developed in one of the flexible hoses connected to the pump. The end result was I found it easier to remove the hoses from the pump cut out the perished part of the tube and re-connect them via some rigid pvc pipe, bypassing the pump completely.

Spin drying and the future of our laundry needs

Without a doubt removing excess water at the end of the process is the most significant improvement to make. To this end I have obtained from my local dump another non-electronically-functioning washing machine. I propose to set this up as the bicycle-powered washing machine and to convert the existing machine to a more efficient spin-drier by altering  the gear ratio.

When setting up this next machine I will endeavour to fix the drum more securely to the machine frame. This, I now realise, would be an ideal use for the brackets normally supplied by the manufacturers specifically for transporting the washing machine.

Future Projects - Mark 3 Laundry

Next year I intend to design and create a solar water heating system which will link directly to the machine. This will obviate the need for the alternative hot water sources, we use at the moment, viz water heated on our wood cooker and in Summer, by means of a couple of plastic bush-shower bags.

..and now if you'd like to, sit back and watch the film

Have washing machine, will travel! All the best and thanks for dropping by. Please feel free to share this article, comment and/or ask for further information.

Until next time!

Cheers, Andy

© Andy Colley 2015

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USEFUL LIVE LINKS

The Great Spin Speed Debate



G Force RPM Calculator



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