Lift Bridge Mechanics

Yep,  looks good to me.  I think you've hit the nail right on the head. OK, I've got it.  Now, if I can just explain it.

 

Get a piece of wood roughly the same size as the block holding your bridge hinges and about 2' long.  Lay it along  the top outside edge of your lift bridge in line with the block holding the bridge hinge.  But, with one end about 1" away from the wood block holding the bridge hinge.  Now, you get another hinge matching your bridge hinges.  Mount the new hinge on the end of this new strip of wood farthest away from your bridge hinges.  Leave the end closest to your bridge hinges loose.  When you raise the bridge this new piece of wood will automatically fall away from the bridge.  Keep raising the bridge until the loose end of this strip of wood hits the top of the platform and stops the bridge.  VOILA!!!  It acts as a leg.

 

Rick

Rick,

 

Thanks for your reply. I am really looking to use some sort of device that I can put under the bridge so that it is out of sight. What you see in photo 1 was put there just for the photo to show the bridge in the up position.

Bill,

 

We use a pneumatic piston on our club layout but it's a curved, double line lift bridge and frequently raises havoc due to changes in humidity (swelling and shrinking the length of the bridge).  It's a very good solution that I think we spent about $50 for the piston.  But looking at your pictures, it looks like your bridge swings very close to your suspended ceiling.  If so, the cheap part me says, "How about a 2x4 hanging down from the overhead to catch the bridge?"

Heres mine with storm door closers, worked for 15 years.

 

 

 

 

The construction of the bridges with lift assist may be helpful.

Runner and Guest Access Bridges

A couple of the bridges use gas springs to hold them in up position.

This is the bridge that started the project.  Construction links are also included.

 

I like Susan's design, lightweight bridge only needs one piston and power shutdown switch to avoid any unplanned engine repairs/maintenance!  Nice work Susan.

I just happened to see in May 2010 Model Railroader page 26 where a guy uses a pneumatic door closer if you have that issue. Has a picture of it and a brief story about it.

Thanks for all the replies.

 

Don, how do you keep the bridge up?

It is held up by the latches that slide from one end to the other on the storm door piston and lock at the cylinder ends just as if you are locking the storm door in the open position.

I forgot.....for the original poster,

 

You can visit here to see how I solved the problem.

https://ogrforum.com/d...nt/11285375712223667

 

It means you have to make one small change, and move your hinge fulcrum back some. You also get rid of the metal hinges....nothing shows other than a facia change.

 

Just another solution.  Good luck in your efforts, Greg

 

The "stay open" retainers/locks are in place.  Those dashpot cylinders will keep the bridge down tight!

I used the same method that Don did, using screen door closures. Works great.

 

Don, how do you hold the small rods that hold the closure to the bridge and table? They want to work their way out.

 

Here are some photos:

 

 

 

If you are referring to the pins on the cylinder and rods, I roughed them up and added a lock washer to give them bite, to prevent that lateral movement of the pin sliding, hope I understood you. 

Don, thanks. Thanks everyone for your help.

Well, back to the drawing board. Just a few minutes ago I went to lift my bridge and broke one of the hinges connecting the bridge to the table. These hinges have been in place for over two years. They are not the heavy duty type. I'm also thinking the two heavy duty door closures I installed may be too much. After I replace the hinges I am only going to install one door closure and see how it works.

Sorry, my fault Rob. In my reply, I failed to note/see that the OP WAS looking for a method to hold the gate in the up position.,...which is what those door closers do, and as you point out, keep tension on it when down. I guess I assumed gravity would do that, and so I viewed their purpose as being to help raise the gate.

 

My reply in my post, addressed the hinge and then holding that back....which is not what was requested in the OP.

 

Next time, I should read better! Greg

After installing new hinges I install one screen door closure centered underneath the lift bridge. Instead of using the included pins I used screws with lock nuts. So far everything seems to be working ok. I will buy extra hinges so I will have them on hand if they break again.

 

 

Looks Good Bill!

Great thread. Susan Deats has a great link with detailed instructions with drafting quality drawings for her lift assist Atlas bridge, located in the thread above.

I think what you are looking for are automobile hatch lifts.

 

 

They can support more than 100 pounds and cost about $15 each.  Try your local auto parts store.

 

Jan