Hooke’s Joint Flexagons

I’ve added a sub page on Hooke’s joint flexagons. Hooke’s joint flexagons were first described by Engel, who calls them ‘hybrid flexagons’, but ‘Hooke’s joint flexagons’ is more apposite. The characteristic feature of a Hooke’s joint flexagon is that adjacent leaves are hinged to either face of an ‘intermediate leaf’’ The hinges are at right angles so the intermediate leaf is a Hooke’s joint.

Coiled Springs as a Power Source

Mainsprings are coiled steel ribbons that have been used as a power source for centuries. A major disadvantage of mainsprings is that they do not deliver a uniform torque during unwinding. In service mainsprings are subjected to low cycle fatigue loading, which can be either uniaxial or biaxial. They can either fail in fatigue or fail by becoming tired due to shakedown into a shape where they no longer deliver adequate torque. Some features of the behaviour of mainsprings used as power sources are described and illustrated by examples. Detailed theoretical analysis is difficult so mainsprings are usually designed by using well established rules of thumb. Correct lubrication is important. To viewthe article click on the following link and then on the link that appears in the preview. I have also added the link to the Clockwork motors and Mainsprings sub pages.Coiled 4A

A Quotation

I’ve added the following quotation to the Quotations page.

As you go into conflict, quite often the enemy does things you do not expect them to do – they really are most uncooperative.
Rear Admiral Rees Ward Professional Engineer. 4 November 2009, 21.

Metal Fatigue

I have now added a Metal Fatigue page, together with a Crack Paths sub page. The latter includes a link to the text of a lecture, ‘Fifty years of crack path research’, which I presented at the International Conference on Crack Paths,(CP 2009), Vicenza (Italy), 23-25 September 2009.

Serious Fun with Flexagons

My book ‘Serious Fun with Flexagons. A Compendium and Guide.” has now been published by Springer. For details see the Publications page. The book includes accurately drawn nets for over 100 flexagons, many of which have not previously been published. Photographs of flexagons in the book are reproduced in black and white. For colour versions of the photograps see the Serious Fun with Flexagons sub page.

Two Qotations

I’ve added the following qotations to the Qotations page.

If you can’t spot the sucker after 20 minutes at the poker table, chances are th sucker is you.
Financial Times. 29/30 August 2009.

He often claimed that God had blessed him with the gift of a delayed hangover, one that kicked in only when he had done his day’s work.
Keith Waterhouse. Obituary. Sunday Times. 6 September 2009.

Some Quotations

I have added the following quotations to my Qoutations page.

Remembrance and reflection how allied!
Pope. Essay on Man.

Let us not burden our remembrance with
A heaviness that’s gone.
William Shakespeare. The Tempest.

Sweet as love,
Or the remembrance of a generous deed.
Wordsworth. The Prelude.

The memory of the just survives in Heaven.
ordsworth. The Excursion.

A Quotation

I have added the following quotation to my Qoutations page.

To act for a young man with a penchant for mooning at police cars opens your eyes to what frustration means
Andrew Caldecott. The Author, Summer 2009, CXX(2), 59.

Synchronous Clocks

The Synchronous Clocks sub pages now include brief descriptions, including photographs, of 28 synchronous electric clocks by 16 different makers. More clocks will be added over the next few months.

Model Mechanic

Model Mechanic is a construction system simialr to Meccano. The manufacture’s description is ‘Nostalgic construction kit complete with miniature screwdriver and spanner. Different kits allow a helicopter, motorbike or racing car to be constructed from the metal shapes, bolts and nuts following the enclosed instructions. All pieces are interchangeable, so if more than one kit is purchased they can be combined to create even more impressive models.’. The hole spacing is 1 cm so Model Mechanic is not compatible with Meccano. The thread is M4. The available sets are all simple. A jeep is described in the Vehicles sub page.