RailPro User Group

General => General Discussion => Topic started by: Alan on December 20, 2020, 05:58:06 PM

Title: Old Skool Brakes
Post by: Alan on December 20, 2020, 05:58:06 PM

(http://www.lkorailroad.com/wp-content/uploads/2020/12/DSC_3408-500x333.jpg)

(http://www.lkorailroad.com/wp-content/uploads/2020/12/DSC_3386_crop-500x432.jpg)

http://www.lkorailroad.com/brakes-on-the-hill/ (http://www.lkorailroad.com/brakes-on-the-hill/)

Title: Re: Old Skool Brakes
Post by: G8B4Life on December 21, 2020, 04:05:03 AM

Old Skool alright, I first remember seeing this mechanical pin method back when digital camera's were 640 x 480 and you stuck a 3.5" floppy disk in them but I digress...

Nicely engineered cranks Alan. They look like they could be commercially molded items. Now to save time on the geometry math you could have thrown in a heartbeat shaped bend in the wire (depending on how springy the wire is) to automatically compensate for the difference in throw.

- Tim

Title: Re: Old Skool Brakes
Post by: Alan on December 21, 2020, 05:44:22 AM

You are very intuitive Tim. I did use a heartbeat wire to validate the math and to final set the length of the installed wire. The wires lay awfully close to the Tortoise case so I didn't want a heartbeat wire on a permanent basis. It would contact the Tortoise if it twisted any at all.

(http://www.lkorailroad.com/wp-content/uploads/2020/12/DSC_3395.jpg)

Title: Re: Old Skool Brakes
Post by: G8B4Life on December 21, 2020, 07:50:38 AM

Quote from: Alan on December 21, 2020, 05:44:22 AM

...The wires lay awfully close to the Tortoise case so I didn't want a heartbeat wire on a permanent basis.

I think secretly you just enjoy doing math; the trains are just the cover up for it  :P

If I had done that I would have just kept the heartbeat wire or in your eyes probably over engineered it (either an inner and outer shaft for the cranks with a set screw or the same sort of method as a prototype switch machine deals with over throw of the throw bar), ie, no math!

- Tim

Title: Re: Old Skool Brakes
Post by: Alan on December 21, 2020, 08:59:02 AM

We think alike. Actually did something similar on a much bigger build. The x axis control of my post pounder uses 1" threaded rod through a bracket. Slid over the rod on each side of the bracket are big block Chevy valve springs. Over-center adjustability and flexibility in the same package!


Sorry, only pic I have of the springs.