36x60x54 Twin Tandem Mill Engine
- Thread starter Kawka777
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I lost the source on these photos (not mine).
The links would appear to be two-piece, bolted together, with a forked connection on the side ?
So the slot in the link is 90 degrees to the typical position ? Am I seeing that correctly ?
.
The links would appear to be two-piece, bolted together, with a forked connection on the side ?
So the slot in the link is 90 degrees to the typical position ? Am I seeing that correctly ?
.
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In practical terms as this is not going to be an exact copy I think it would be easiest to base the valve gear on a known model, just scaling it to suit your engine.
The curved expansion link is the most common and not too hard to machine with a rotary table so finding suitable examples would be easy and save getting bogged down in designing from scratch as you have enough on your plate with this engine already.
Something like this would work, all the parts were quite straightforward to make. The two "D" shaped bosses are what the eccentric rods connect to, lever bottom left goes to the control rod that is moved to change position.
The curved expansion link is the most common and not too hard to machine with a rotary table so finding suitable examples would be easy and save getting bogged down in designing from scratch as you have enough on your plate with this engine already.
Something like this would work, all the parts were quite straightforward to make. The two "D" shaped bosses are what the eccentric rods connect to, lever bottom left goes to the control rod that is moved to change position.
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I'm not sure you have your links from the bottom bell crank in the right place.
It is usual to raise and lower the expansion link. As it is raised or lowered you then get a "straight line" from the eccentric and it's rod to the horizontal rod that goes to the die block and then onto the valve. If you do it as your sketch suggests then the double link will be angled.
If the double links are to be raised and lowered then I would have expected to see them lifted nearer to the right hand end, this combined with a straight slot rather than curved is Allen valve gear not Stephensons
It is usual to raise and lower the expansion link. As it is raised or lowered you then get a "straight line" from the eccentric and it's rod to the horizontal rod that goes to the die block and then onto the valve. If you do it as your sketch suggests then the double link will be angled.
If the double links are to be raised and lowered then I would have expected to see them lifted nearer to the right hand end, this combined with a straight slot rather than curved is Allen valve gear not Stephensons
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The most common arrangement of a Link Motion, with the expansion link moving up and down is indeed known as Stephenson, although it was invented by his employee Howe.
If the expansion link moves on a fixed rocker, and a radius rod to the valve rod moves up and down the link, then the link is curved the other way, towards the cylinder, and it is called Gooch.
If the expansion link and radius rod both move, in opposite directions, and the expansion link slot is straight, then it is called Allan.
If the expansion link moves on a fixed rocker, and a radius rod to the valve rod moves up and down the link, then the link is curved the other way, towards the cylinder, and it is called Gooch.
If the expansion link and radius rod both move, in opposite directions, and the expansion link slot is straight, then it is called Allan.
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