Author Topic: How does this parallel motion work on Mary Beam engine  (Read 2309 times)

Offline geoff5269

  • Full Member
  • ****
  • Posts: 152
How does this parallel motion work on Mary Beam engine
« on: December 20, 2017, 08:41:56 PM »
I'm thinking of Building the Mary a bit smaller at 75% but when looking at the parallel motion I couldn't see any relationship of the parts as there is with a Watt parallel.
Also I notice that when the beam is level the piston rod and links are not in line as you would expect.
I might have to make a test piece  to try this out . Any ideas
Geoff

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 15293
  • Hampshire, england.
Re: How does this parallel motion work on Mary Beam engine
« Reply #1 on: December 20, 2017, 08:48:35 PM »
How about looking at it in colour  :thinking:

It runs ok  ;)

Jo
Enjoyment is more important than achievement.

Offline crueby

  • Full Member
  • *****
  • Posts: 18554
  • Rochester NY
Re: How does this parallel motion work on Mary Beam engine
« Reply #2 on: December 20, 2017, 09:19:21 PM »
Those color pictures show the linkage at the very top, till I saw that I thought something was missing from the drawing in the first post. Amazing what the brain can miss!

ChuckKey

  • Guest
Re: How does this parallel motion work on Mary Beam engine
« Reply #3 on: December 21, 2017, 12:02:07 AM »
Also I notice that when the beam is level the piston rod and links are not in line as you would expect.

I would not. I would expect the 'connecting rod' link to swing an equal amount either side of vertical through the stroke.

Online gbritnell

  • Full Member
  • ****
  • Posts: 2460
Re: How does this parallel motion work on Mary Beam engine
« Reply #4 on: December 21, 2017, 03:28:59 PM »
One of the things I found when building my Mary engine was that the layout for the parallel linkage left a little to be desired. They have you make the parts then swing the parallel ling against the stanchion and scribe a line for the center point. Apparently not many people used trigonometry at that time.
I did my own layout and produced decimal dimensions for all the bits and pieces. It worked out fine and is a very stately engine.
gbritnell
<a href="https://www.youtube.com/watch?v=bmBgGAN-7aE" target="_blank">http://www.youtube.com/watch?v=bmBgGAN-7aE</a>
Talent unshared is talent wasted.

Offline geoff5269

  • Full Member
  • ****
  • Posts: 152
Re: How does this parallel motion work on Mary Beam engine
« Reply #5 on: December 22, 2017, 11:26:04 AM »
Thanks for the replies and pictures, this engine does seem to have a very long stroke and the parallel motion copes with that so it must be OK.
I hope it still works if I reduce the size of the engine.
Geoff

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal