Hypocycloidal Pumping Engine
The prototype of this engine, built in 1805 or 1806 to pump water, is on display at The Henry Ford Museum in Dearborn, Michigan. The engine was discovered by Henry Ford in 1928 at The Bradley Foundry in Stourbridge, England .
It features Murray's 1802 invention of the Hypocycloidal Gear motion which converts the linear force of the piston and rod movement to rotary motion driving the pumps and flywheel. Murray developed this method to circumvent the control of steam machinery by the many patents held by James Watt's company, Bolton & Watt.(See some details at the French Beam Engine Page)
This engine also exhibits Murray's creation of the portable (deliver by ox cart!), and fabricated Cast Iron (no wood or foundations) engine, to save installation costs. It also features his invention (1802) of the short stroke "D" valve....still used today!
Note the compactness of this design. The A frame provides a rigid framework for the two "variable displacement" water pumps. The pump outputs are delivered to the dome shaped receiver which smoothes out pulsation's of the single action pumps (180 degrees out of phase). This engine was considered to be very sophisticated for its day.
Photo by Rich Carlstedt: 1975
Only one of kind exists. However another Hypocycloidal Engine by Murray is displayed at the Birmingham, England Science Museum but, it has no pumps and is much simpler in construction.
Rich Carlstedt's Model
The model scale is 1/8th or 1.5 inches to the foot. Flywheel diameter is 9".
It is made entirely of solid block cast iron, steel material, and bronze for bearings. No castings or plating were used. Parts were machined, forged , ground /sanded by hand and polished. With a cylinder bore/stroke of 1.125 X 3.00, the engine runs on 1# of air pressure. The bricks were molded from Polyclay. The Wood Base is Brazilian Cherry.
The model was started in January of 2000, and finished in April of 2002. Rich has well over 1,000 hours in machining and finishing with an additional 350 + hours for scaling proto-type photos to AutoCAD and detailing dimensions. Research time and travel to the Ford Museum are not included.
The inspiration and construction of this engine is dedicated to the memory of Emery Ohlenkamp, a dear friend of Rich's.
Emery passed on in December of 1999.
This view shows the steam cylinder and its attachment to the pinion gear. The piston rod is starting its downstroke and forcing the pinion gear to rotate the crankshaft clockwise, while the pinion itself rotates counterclockwise!
The bottom of the cylinder shows the exhaust pipe flange with its 3-hole pattern. The valve box is to the rear and right of the flange.
The front of the pumps reveal the inlet side of the pumps and their check valve housings next to the base (below and either side of the Dome!)
The valve rod which operates the "D" valve is visible behind the outlet piping as it passes horizontaly past the pumps to the flywheel side of the engine.
The pump cylinder connecting rods (which look like forks and can be seen on the full model 2 pics up) shows the angular diversity of the cranks and are fastened to the pump pistons to drive them. The pumps receive their power from the double reduction gear drive at the center top of the engine. (Visible in 1st picture of the model.) The two short vertical rods between the forks are the pump piston rods and are guided against side thrust by the bars which go across the pump bowls.
The bowls (Left one visible) were used to "prime" the pumps before operation. The bracket across the bowl is realy a pump piston rod guide!
Here's a close view of the steam cylinder piston rod&pinion crank pin bearing. Note the bearing adjustment take up wedges and key.The pinion gear is 1.5 inches in diameter.
Note the scaled tooth profiles ! Hypocycloidal Gear and Pinion (Below)
Note that the piston rod is vertical in all pinion positions
(The pink hilite is a reflection)
Pinion gear with steam
cylinder piston rod
at top center.
With pinion at 90 °
the rod is midway
down stroke with pinion
at mid stroke.
Pinion at 180. °.
The bottom of
at 270°The rod is
midway on up stroke.
Here's the pump bull-gear and bearing cap for the pump crank shaft. Note the clearance between the cap and the bearing base. This clearance allowed the bearing to be adjusted for wear. The double nuts maintained the clearance settings.
A unique method for the 1800s'!
Detail and accuracy of this outstanding scale model are reflected in this valve rod translator crank bearing. The tapered gib is only .035 (.75mm) thick and the 5-piece assembly is just ¼" high!
Thanks for visiting this page. If you have comments and/or questions about this exqusite model, e-mail my friend and machining mentor, Rich Carlstedt, and be sure to visit The French Beam Engine.
Photos by RandomRon.net Return to top of page