Author Topic: Elmers Ropedrive engine  (Read 770 times)

Offline Johnmcc69

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Elmers Ropedrive engine
« on: March 12, 2018, 07:33:20 PM »
I'm finishing up CAD models of Elmer's Rope drive engine & generator & can't get my head around the belt drive. How does the belt tensioner work? I think this uses 6 belts (Rope) off the engine flywheel & maybe a 7th that comes off the jackshaft (?) & runs to the idler pulley. I just don't understand how this 7th(?) belt keeps tension to the other 6(?). I understand how the weight provides the tension, but what belt or belts are ran through the idler pulley? I did a search on the web for this engine & found a video by Marv K., but it's hard to tell the routing. Maybe Marv can help me out...

 Very cool engine & set-up with the gen. I'm surprised there haven't been more builds of this... :stickpoke:

 John

 (I tried attaching Elmer's drawings, but too large. They can be found on the "John-Tom" site, #39 Rope drive...)

Offline crueby

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Re: Elmers Ropedrive engine
« Reply #1 on: March 12, 2018, 07:44:14 PM »
Looks to me like there is just one long rope that starts at one end of the pulleys, goes back and forth stepping over one groove at a time, at the last groove it goes through the idler pulley and back to attach to the beginning of the rope again - it is one long endless loop, not 6 or 7 individual ropes.

Offline toolznthings

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Re: Elmers Ropedrive engine
« Reply #2 on: March 12, 2018, 07:48:44 PM »
Hi,

Looked at the plans. This stuff drives me crazy with the poor reproduced pictures.  :o I'm probably more lost than you on this one !
Would be a neat build if you can get it figured out.

Brian in Ohio
Thanks for the visit !
Brian

Offline mklotz

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Re: Elmers Ropedrive engine
« Reply #3 on: March 12, 2018, 08:07:39 PM »
I'm finishing up CAD models of Elmer's Rope drive engine & generator & can't get my head around the belt drive. How does the belt tensioner work? I think this uses 6 belts (Rope) off the engine flywheel & maybe a 7th that comes off the jackshaft (?) & runs to the idler pulley. I just don't understand how this 7th(?) belt keeps tension to the other 6(?). I understand how the weight provides the tension, but what belt or belts are ran through the idler pulley? I did a search on the web for this engine & found a video by Marv K., but it's hard to tell the routing. Maybe Marv can help me out...

 Very cool engine & set-up with the gen. I'm surprised there haven't been more builds of this...

Always ready to help somebody from PA, John (I grew up in Allentown).

There is only one, long, closed loop belt.  The grooves on the flywheel and jackshaft pulley are parallel. This is obvious from the first photo below.

The belt is wound on the parallel grooves and the transition from one side of jackshaft pulley to the other is done through the idler pulley.  The second photo shows how this happens...





One of the toughest tasks in the construction of this engine is making that belt.  I used three-strand cord.  After separating the strands at each end I plaited them back together and sewed them in place with fine sewing thread.  To get the belt length right, I did all this plaiting and sewing with the belt in situ on the engine.  This required using some gear from my model sailing ship rigging days to hold everything in place while the work was done. 

In retrospect, I should have wrapped the cord to determine the required loop length and done all the plaiting and sewing off the engine.  Then install the belt and, if the tensioning can't take up the slack, move the jackshaft stand until it can. 

Regardless, allow for movement of the jackshaft stand in your model.

Good luck.  I'll look forward to following your build.
« Last Edit: March 12, 2018, 10:40:18 PM by mklotz »
---
Regards, Marv


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Offline JULIUS

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Re: Elmers Ropedrive engine
« Reply #4 on: March 12, 2018, 08:33:11 PM »
John

If you go to section Plans and Drawings you will find on the second page ELMERS VERBURGS STEAM ENGINES
If you click on that you will find my drawings.
Go to  page 6 and you will find Chapter 39 Part 1 PDF drawings, on page 7 are some EDRW drawings of the same engin. There are the drawings of  Elmers rope drive.
May be my plans might give you some help.

Kind regards

Julius

Offline Johnmcc69

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Re: Elmers Ropedrive engine
« Reply #5 on: March 14, 2018, 07:47:03 PM »
Thank you gentleman, we have it figured out. One continuous belt. Thanks for the pictures & explaining this Marv, very helpful. I wish I was in California where you are right now, too cold & snowy here in good 'ole PA. Thanks also to Julius, as usual, very nice drawings. I usually follow your drawings/plans posts, but somehow missed that one....

 Sorry, there won't be a build log from me, I don't have the machines (Yet). I'm left to drawing them up until I either have my own or access to them. Sigh...

 Attached is a drawing of the finished item.

 John