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Here is the hinge idea I came up with to have the roof open widely, but not hit the steam dome for the Climax locomotive model I am building. Another requirement is that the roof can stay in the open position for access to the backhead.



The scissor action lifts and swings the roof back from the steam dome as it opens. By design, the maximum opening occurs when one of the scissor arms is vertical. The small swing link at the rear of the roof is parallel to the roof line at this inflection point. From this point, you can lower the roof slightly in a propped open position caused by the scissor arm pressing on the roof, or you can swing the link in the other direction to close the roof.







Any thoughts? Are there simpler ways to achieve the same result? A simple pivot from the forward corner would let the roof hit the steam dome.

Ed
 

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Looks like a great idea to me, I personally cant stand the Accucraft flip to the side or foward hinges that are just wire as they all hit the domes or piping going foward and to the side well dont plan to have another train run next to ya.

I was looking at the rest of the log and I cant belive how fast you are coming along. Looks great. Now with the CNC you should make one of the pumps a water pump. Heh I have 1/8 scale drawings if you want to try of a single. The question is will the bobbin valves workl that small.
 

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Ed,
Looks like it works well but has a lot of parts. What about a car hood hinge approach complete with a spring so the roof stays up until the operator "wants" it to fold down.
 

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Discussion Starter #4
Hi Jason,



Thanks. The loco already has a water pump - it is unusual in that it is mounted on the frame and driven by the center shaft instead of a truck:







So I don't think I'll be building a second pump, especially not a scaled prototype!



Chris, As far as a car hood lift - I am thinking I would need complex curved hinges that would be hard to fit in the cab and not be seen through the windows.
Yes, there are a lot of pieces to the scissor hinges, but each piece is simple. Also, they will all stay hidden under the roof and above the windows.
 

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Excellent design concept but I think it would be difficult to execute in a manner where it would be able to withstand the normal opening and closing cycles during an afternoon steam-up. The rails, slots and pins would be very delicate and difficult to maintain in proper geometry for consistent operation.
 

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FWIW... I guess I was thinking of a 50's-60's car hood hinge I remember as much simpler. A knife type hinge with a spring to keep the hood from falling and a stop block limits the hinge's opening to maybe 45(?) degrees. For the loco roof a stop block limits the hinge opening to +/- 90 degrees, though not required a nice additioon would be a counterbalance spring so the hinge cannot close unless you pull at the pivot point. The stop block on a simple knife hinge is a lip on one side that stops the other side's rotation. You could also say the stop block also acts as a kind of latch that holds the hinge open. The loco roof is so lite seems to me the knife hinge would be small; 2 lengths 1/4"-5/16" x ~1/16" x ~2", and that size would be easily concealed. Like the car hood you will need a pivot point on the roof itself at the front corners.


Probably clear as mud but hope it helps. There are a number of other things you could use instead of a spring to keep the hinge from closing while the roofs up. If you want info on some of these email me.
 

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I just completed a Salem Steam models Bayer Garrett kit, and used the small rare earth magnets from Radio Shack to retain the roof and tank tops. Holds them tight and easily removable.

Thanks
Steve
 

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My issue of remoavable roofs is when at meets running you always need a polace top put the cab as some people are somewhat careless and lay the roof on adjacent tracks. Not smart with other trains running
 

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Posted By steveciambrone on 09/09/2008 9:30 PM
I just completed a Salem Steam models Bayer Garrett kit, and used the small rare earth magnets from Radio Shack to retain the roof and tank tops. Holds them tight and easily removable.
Thanks
Steve

Perhaps this is a dumb idea, but what about making the roof completely removable, using magnets as Steve suggests above, but design it such that the roof can be re-attached in the raised position, held securely by the same magnets? Thus, there are no hinges, latches, or any moving parts, and there si less chance of loosing the roof or leaving it on an adjacent track.
 

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Posted By steveciambrone on 09/09/2008 9:30 PM
I just completed a Salem Steam models Bayer Garrett kit, and used the small rare earth magnets from Radio Shack to retain the roof and tank tops. Holds them tight and easily removable.
Thanks
Steve




Please show us your Garrett......:)

tac
 

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Try this, our club the Puget Sound Garden Railway Society Live Steamers commissioned a company to silk screen our club logo onto cotton aprons for our members and as a fundraiser. These cotton aprons are a dark green and have three pockets across the front of it. These pockets are excellent for putting small items like cab roofs, fire starter sticks, rags and the brass tender pump handles common on many of our models. I have an Aster S2 that has a cab roof that slides on and off as well as a platform over the water section of the tender. When I need to access any of these areas I simply pluck it off the locomotive and slip it into one of the pockets. The apron also serves to protect ones clothing from the occasional shot of oily water out of one's stack.
 
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>>Quote - Excellent design concept but I think it would be difficult to execute in a manner where it would be able to withstand the normal opening and closing cycles during an afternoon steam-up. The rails, slots and pins would be very delicate . . .
 

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Discussion Starter #15
I'm with you Curmudge. I am using 1/8x3/16 brass with 3/32" stainless steel pins. The hinges will be far more durable than what GNSteamer is used to seeing with manufactured locomotives. The cab roof and sides will be made from 1/16" thick brass.



 
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I withdraw my comments above, which were made in response to a post I mistook to be about the water pump rather than the cab roof mechanism, thus they should not have made any contextual sense to anyone.
 
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