Stationary Engine Kits
Anthony Mount Models
Simpon and Shipton’s Short Stroke Engine 1851
This engine was patented by two Manchester engineers, Joseph Simpson and James Alfred Shipton in 1848. It is a rotary steam engine, but it still uses connecting rods to drive the crankshaft. The “cylinder” or perhaps better described as a chamber, sits on a table carried on four short columns. Inside the chamber is a “piston” lying on its side. Passing through the piston is an eccentric shaft, connected to the outer ends of the shaft are cranks. Connecting rods drop from these cranks to the crankshaft carried on bearings fixed to the base. Steam enters the chamber through a balanced slide valve and impinges on the side of the piston rolling it around inside the chamber.
The claim for this arrangement was a compact smooth running engine. Against the design are the problems of sealing the length and ends of the piston. Full size this was achieved by having a flat spring loaded plate bearing against the side of the piston. The ends were sealed by split coned rings seated in coned recesses in the ends of the piston. By expanding the ring with a wedge the ring rode up the coned recess and increased the length of the piston sealing the ends. In the model the length wise sealing is achieved by using a very slight interference fit. The ends are sealed with rings of graphited yarn dropped into grooves machined in the piston ends.
Construction of the model is quite conventional without any odd machining practices. It can be machined on a 3 1/2” lathe, the flywheel being 9” (225mm) diameter. There is quite a lot of milling involved, and while this could be done using a vertical slide. A vertical milling machine does make things a lot easier. The bigends are of the strap and coffer type. Castings are available for the base, table, cylinder, piston, covers, steamchest, steamchest cover, eccentric strap and flywheel. There are 23 drawings plus a parts list and all are of A4 size. The drawings have both metric and imperial dimensions. Except that all drill sizes are given in metric as these are now the preferred size.
The engine does look very interesting when in motion, there are levers gyrating all over the place. It is also very free running and only requires a wisp of air to get it running. How many of these engines were built full size is unknown, but an engine was exhibited at the great exhibition in 1851 where it drove textile machinery. There is also a reference to the engine in the “Engineer” in 1862. Still with the same cylinder arrangement, but with a different drive mechanism.
The model was serialised in Engineering In Miniature in August 1994 to May 1995.