How to hinge a trapezoid

Rennie Heuer

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I'm designing a stand for an antique Edison cylinder player for a client. We were thinking of concealing several pull out shelves for cylinder storage. For cleaner lines we thought to put those shelves behind a single door. He wants the legs canted towards the inside. My initial solution was to place tapered filler strips inside the leg so I would have a place to put my hinges as this allows for a rectangular door opening. He wasn't crazy about the fillers and asked if those could be eliminated. That leaves me with trying to hang a trapezoid. I can't seem to figure out how that can be done, or IF it can be done. To my mind you'd be opening the door 'up hill' and all it would want to do is slam shut.

Any ideas?

Here's a quick drawing of the initial idea.
Edison player stand1b.jpg
 

Bill Arnold

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My first thought was to keep the overall outer shape of the legs as they are, but straighten the inside edge to a vertical, so the door itself can be squared off. To maintain the trapezoidal effect, the inner parts of the door could be modified a bit.
 

Leo Voisine

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Without a layout in 3D I can picture the hinges to be Vertically in alignment. The door would need to have offsets to mount the vertical hinges. The door side is not vertical - but the hinges must be.

IF - I could make Solidworks work, which I cannot, I could lay it out in a few minutes with motion applied.
It can also be done in Fusion 360, but my skill level there is much lower.

Perhaps a full scale shop made model.

I am not sure what the hinges would look like.
 

glenn bradley

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The door could be a false front for a squared opening. Think about some of the cloud lift drawer fronts we deal with. The visible surface does not reflect the "box" behind it.
CoD Top Drawer (5).jpg . CoD Top Drawer (6).jpg
You would be looking at some sort of cup hinge to be able to swing out that far using linkages instead of just a simple pivot point.
corner cup hinge.jpg
For a narrow opening the room taken by the hinge assembly sometimes makes the opening awkward.
temp.jpg
 
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Rennie Heuer

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My first thought was to keep the overall outer shape of the legs as they are, but straighten the inside edge to a vertical, so the door itself can be squared off. To maintain the trapezoidal effect, the inner parts of the door could be modified a bit.
I thought of that too, but the client wants both the inside and outside to be angled. Additionally, those edges are not parallel.


Without a layout in 3D I can picture the hinges to be Vertically in alignment. The door would need to have offsets to mount the vertical hinges. The door side is not vertical - but the hinges must be.

IF - I could make Solidworks work, which I cannot, I could lay it out in a few minutes with motion applied.
It can also be done in Fusion 360, but my skill level there is much lower.

Perhaps a full scale shop made model.

I am not sure what the hinges would look like.
As this is a period looking piece, the hinges need to be also. Just no way to make them vertical that I can see other than the offsets you mention and are in my initial drawing.


The door could be a false front for a squared opening. Think about some of the cloud lift drawer fronts we deal with. The visible surface does not reflect the "box" behind it.
View attachment 119286 . View attachment 119289
You would be looking at some sort of cup hinge to be able to swing out that far using linkages instead of just a simple pivot point.
View attachment 119287
For a narrow opening the room taken by the hinge assembly sometimes makes the opening awkward.
View attachment 119288
European hinges on a period A&C piece!!! Blaspheme!! I like the idea of somehow offsetting the door - worth exploring.
 

glenn bradley

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I thought of that too, but the client wants both the inside and outside to be angled. Additionally, those edges are not parallel.

The joys of working through things with the client :). Unfortunately geometry runs contrary to his wishes.
European hinges on a period A&C piece!!! Blaspheme!! I like the idea of somehow offsetting the door - worth exploring.

You are not wrong. Sketchup is your friend here. You can make the door and a pivot point a group

McLaren Plywood Rack (45).jpg
and then move the pivot point around to see where things run into each other when the door pivots on that point.

The knife hinges would allow you to conceal the hinges. The pivots could be in line top to bottom. The fettling then would become the inward swing clearance for the door portion to the right of the bottom hinge pivot point. Remember . . . Have fun!
 
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