Lift up bridge questions

[GAP]

New Mounting Block built out of steel C Purlins, Bridge Supports made out of Aluminium as will be most of the bridge.
Aluminium was chosen because it was light enough for SWMBO to lift the bridge, if it was made out of the hardwood as was original idea she would struggle with the weight.

Mounting Block


Hinge closed


Hinge open (note mounting block attachment bolts)


Supports closed (still to be trimmed to fit)


Support in open position

 

[GAP]

After testing the track alignment the supports will have to be re aligned but that is all OK as it is just a simple re-drill of 2 of the 3 hinge mount holesand re attach.

 

[PhilP]

Is the pivot high enough? - Depending where the cut is made, and if there is a void for the end of the bridge/track to sit in when open..

 

[GAP]

Is the pivot high enough? - Depending where the cut is made, and if there is a void for the end of the bridge/track to sit in when open..

The pivot is at the correct height,
The cut will be made at 45 degrees with the high end starting at the end of the baseboard ,
The void for the track to fold into is close to 60mm wide which is the height of the support plus some.

 

[PhilP]

The pivot is at the correct height,
The cut will be made at 45 degrees with the high end starting at the end of the baseboard ,
The void for the track to fold into is close to 60mm wide which is the height of the support plus some.

S'always worth askin' the question, though..

 

[GAP]

S'always worth askin' the question, though..

As I always say to SWMBO when she asks "will this work?" I answer "I'll make it work!!"

 

[GAP]

Well what a difference a day makes especially when someone has asked a question that just niggles in the back of the mind.
I started laying the approach track to bridge and then decided to revisit the pivot point because sometimes things just need a second look.
Turns out that pivot is way to low it is OK for the bridge supports but when track height is added there is yawning gap between the bridge track and the approach track when the bridge is closed.
I have now built a proof of concept jig that appears to let me do what I want.
If I cut the track vertically the gap is there cutting the track at 45 degrees is the secret to doing this from what I have discovered so far.
Thanks Phil for asking the question because it saved me a heap of work because I would not have looked at the bridge till the track was laid and it was time to cut it.
As with all good engineering it is sometime to get a peer review as a fresh set of eyes can see something that is being overlooked.
So bridge design MkIII is now on the drawing board.

 

[PhilP]

 

[GAP]

Bridge Design MkIII proof of concept jig has been built and the design has been tested with positive results.
As previously stated the secret of the opening is the 45 Degree cuts in the rail which allows the moving rail to drop away from the fixed rail without fouling.
The moving arm of the hinge is level with the baseboard and the gap that the rail folds into is not real wide.
The error I made with the MkII was that I put the bridge support on top of the hinge and when the rail was added the gap was just unworkable as the support folded into it, the bridge support will now be level with the top of the hinge and will not fold into the gap.

So now the bridge construction can now begin following the concept principles.

Closed


Open


Rail cut close up (closed)


Rail close up (partly open)

 

[trammayo]

You could modify a couple of rail joiners to have a full width (as in base of rail) opening along half the joiner's length, then slide them on the ends of the bridge rails (and permanently secure). They would the make the rails align in both planes (horizontal or vertical). Just a thought looking at the pics. I use this method to locate my big swing bridge.

 

[GAP]

You could modify a couple of rail joiners to have a full width (as in base of rail) opening along half the joiner's length, then slide them on the ends of the bridge rails (and permanently secure). They would the make the rails align in both planes (horizontal or vertical). Just a thought looking at the pics. I use this method to locate my big swing bridge.

I do not want to use joiners because this bridge leads to a sitting area that will be used by people, I am trying to keep the opening of the bridge as simple as possible.
This may be used by people on the way to the Loo in the house after drinking a few beverages, hence the keep it simple principle.

 

[GAP]

The new mounting block has been made from wood and work on the first hinge has started.
Unfortunately I used some hardwood from the $2 per 1.2M rack and it is cut crooked i.e. 32mm on one side and 30mm on the other.
Luckily I have 2 different sized mounting bolts and the longer one just happens to bring the hinge top level with the baseboard.

 

[JimmyB]

Are you going to have some sort of automated or manual barrier across the track "just in case" a train is running. I am sure your thoughts trains won't run when the bridge is up, but they could be "famous last words".

 

[trammayo]

I do not want to use joiners because this bridge leads to a sitting area that will be used by people, I am trying to keep the opening of the bridge as simple as possible.
This may be used by people on the way to the Loo in the house after drinking a few beverages, hence the keep it simple principle.

I didn't mean to use them as joiners but rather to make them into a permanent locator - they would be hanging downwards when you open the bridge. I can't find my pics to show you what I mean. But keep up the good work - looks nice to be able to sit inside your railway!

 

[GAP]

I didn't mean to use them as joiners but rather to make them into a permanent locator - they would be hanging downwards when you open the bridge. I can't find my pics to show you what I mean. But keep up the good work - looks nice to be able to sit inside your railway!

Gotcha, I have some Hilmans Lift Out Bridge clamps that I am going to use at the opening end to align the rails.
I will fix the rails of the approach by drilling through the rail foot and nailing them to the baseboards
For the hinge end I plan to fix the rails with screws.

 

[GAP]

Are you going to have some sort of automated or manual barrier across the track "just in case" a train is running. I am sure your thoughts trains won't run when the bridge is up, but they could be "famous last words".

Thinking of a spring loaded bolt that is pushed down by the bridge when it is closed, just have to be careful not to make the spring to strong so it does not push the bridge out of the alignment clamps.