[quote user="DS4-4-1000"] [quote user-"D Owens"] As I was reading your post it occurred to me that there is a locomotive that does (did) incorporate piston to axle direct drive. It is a steam locomotive and not either a diesel or an electric, as was the point of this thread, but on the side of interest in things that make you go "Huh?", I thought that I might point out the Shay Locomotive. It had direct drive to not only the engine but to its attached tender as well. It has universal joints that allow flexing of the drive-shaft in both dimensions.[/quote]
To me a Shay still has a mechanical transmission between the cylinders and the axles. I look at direct drive requiring crank pins on the wheels or an axle... .[/quote]
The issue, I think, is more whether any gear-ratio change between 'crankshaft' and wheel speed, which all working Shay designs possess,makes the drive any less 'direct'. (And yes, I think that normal definitions of 'direct drive' specifically exclude even fixed-ratio change-speed gearing, which leaves working Shays, the rod-drive turbine locomotives, Winans Crabs, etc. out.) That still leaves open the possibility that 1:1 gearing, or the provision of quill-like compliance between a crankshaft and coupled wheels (which might have helped the 1912 German design), will not automatically disallow a design from being considered 'direct'. That is more a place for (perhaps nit-picking) semantics and community agreement on a common definition.
Jackshaft drive is just a 'folded' version of rod drive, by definition ratio is 1:1 and all rods srill act on pins. I don't think there is any difference for an arrangement like Kando drive. I don't think it matters whether an engine crankshaft is physically separate from wheels if the drive from crank to wheels is itself direct.
A look at history of the heavy constructon industry may be in order.
1. The mechanical steam shovels used on the panama canal may have been the first use of that type of transmission. They could easily exceed the structural limits of the equipment.
2. By the 1950 most equipment was of the mechanical transmission gasoline and later diesel engines. Again operators could overstress the structural imits. Energy recovery probably exceeded stem by a factor of 2 - 3.
3. Then diesel hydraulic drives came into much equipment. The equipment could have load limiters so that overstressing could not break the equipment. Energy recovery was probable 1-1/2 to 2 times better than mechanical. The problems of broken hoses, pipes, & leaking actuators by debri and wear are a problem.
4. Now with inverters and AC motors equipment can exceed a 95% energy recovery. Electrical equipment can have armour protection and be dust protected. Are the lastest army tanks AC ?
blue streak 1 A look at history of the heavy constructon industry may be in order. 1. The mechanical steam shovels used on the panama canal may have been the first use of that type of transmission. They could easily exceed the structural limits of the equipment. 2. By the 1950 most equipment was of the mechanical transmission gasoline and later diesel engines. Again operators could overstress the structural imits. Energy recovery probably exceeded stem by a factor of 2 - 3. 3. Then diesel hydraulic drives came into much equipment. The equipment could have load limiters so that overstressing could not break the equipment. Energy recovery was probable 1-1/2 to 2 times better than mechanical. The problems of broken hoses, pipes, & leaking actuators by debri and wear are a problem. 4. Now with inverters and AC motors equipment can exceed a 95% energy recovery. Electrical equipment can have armour protection and be dust protected. Are the lastest army tanks AC ?
Probably a question for a different web forum but what Panama Canal equipment are you referring to?
My understanding of the steam shovel fleet for that project is that it was made up exclusively of steam powered,rail mounted, cable operated, limited swing (i.e not 360 degrees like a modern excavators) machines.
Such machines were relatively common in heavy civil construction well before the Canal project, in fact the earliest machines were in use before the civil war (In 1839 a prototype Otis Steam shovel was used to build what became the Boston & Albany railroad line through the Berkshires.. Late in the 19th century and in to the 20th they were acquired by mining and construction firms in large numbers so the machines used in Panama were not custom designed just for that project.
You also seem to be confusing the word "transmission" with "power source" given that the Canal shovels and the large power shovels common in the 1950's used similar cable operated mechanisms to move and operate the digging tool (dipper)..the difference was in the powerplant: diesels replaced the earlier steam engine (actually pre WWII).
As you point out the hydraulic excavator changed all that, although actual energy recovery systems for the hydraulics are a firly new innovation.
The US army has been working on developing hybrid electric drive systems for Armored fighting vehicles but the current main battle tank, the M1 Abrams (designed back in the 1970's), uses a hydrostatic automatic transmission..
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
Our community is FREE to join. To participate you must either login or register for an account.