Standardized clockwork 2006/2007




Introduction

The first Scheffler Reflectors, installed form 1986 onwards at school kitchens in Kenya, were manually tracked. But soon it became obvious that the users would much appreciate a tracking mechanism that makes the reflector follow the daily movement of the sun across the sky automatically. Wolfgang Scheffler then developed a tracking mechanism that could be manufactured locally with parts available in any place: A clockwork from bicycle parts. 1990 the first installations of Scheffler Reflectors in India got equipped with this tracker for the first time.

Since then this mechanical clockwork was redesigned several times in order to make it easier to manufacture and more reliable in its daily functioning.

These developments were recently documented by Michael Tyroller. You may read his article on Different gear boxes for tracking of Scheffler Reflectors.

The latest manual for construction of a mechanical clockwork is available for download on the Solare Brücke website.

By now tracking systems with photovoltaic sensors and drive as well as timer operated systems are being used, too. But the mechanical clockwork is still the preferred solution for installations with few reflectors, especially for single reflectors. Parts are available for little money everywhere. Manufacturing can be done locally in a simple workshop.

The drawback: it requires some skill to construct the tracker precisely enough to make it run reliable for many years without stopping. Of course skill can be acquired, but it also means that manufacturers have to implement quality control mechanisms.

That doesn’t sound too difficult but the reality is:

If we look at the usage rate of installations with one or just a few Scheffler Reflectors, we notice that not all are used well, some even hardly at all. These installations are mainly used by small rural boarding schools, orphanages or hostels. Larger installations (steam systems) for cooking in large institutions or industrial applications are exempt – they are all used to the maximum.

Those institutions that don’t use their reflectors well, report individual problems that could mostly be solved at the level of management and organisation. But it is noticeable that any technical problem usually relates to a failure in the tracking system.

Technical problems have to be solved by the manufacturer of the installation.

Most manufacturers have up to now not managed to fabricate reliable clockwork mechanisms. Some have gone as far as to outsource the job to a company specialized in gear-making.

But still: the mechanical clockwork can not be driven with much force. This means the mechanism must run with very little friction (and that at low cost).

To assist with this problem Heike Hoedt and Sabur Achtari took the initiative of having standardised parts of high precision manufactured in Germany in 2006. A large number of ordered parts maintains the price relatively low.

The basic concept of Wolfgang Schefflers clockwork from bicycle parts was maintained. Some parts were altered for mass production, bearings were improved and the number of parts was reduced. The precise readymade parts eliminate friction and manufacturing inaccuracies. To keep cost and weight for postage low the base of the clockwork still has to be made according to a manual and assembled with the ready made parts.



The set of parts serves for 8m², 10m² and 2,7m² Scheffler Reflectors.  A manual for assembly and construction is ready for download.

Parts can be ordered from Solare Brücke. We charge at the rate of manufacturing, no handling fees, no storage or development charges from our side.  We can post only complete sets for a price of 27,-€ + postage.

Manufacturers of Scheffler Reflectors in India can order a similar set of parts manufactured by Rashron Auto Ltd. in Baroda.

Download:

For parts ordered in Germany (Solare Brücke e.V.):
Cutting List and Part List for standardised clockwork of 8m² or 10m² Scheffler Reflector (german parts)

For parts ordered in India from Rashron Auto Ltd.:
Cutting List and Part List for standardised clockwork of 2,7m² Scheffler Reflector (indian parts)
and
Cutting List and Part List for standardised clockwork of 8m² or 10m² Scheffler Reflector (indian parts)

Manual for assembly of Indian standardized clockwork (2,7m² and 8m²/10m²)