Hello
I am looking for a parallel lift door system that would exist in small dimensions, i.e. 150 mm long, 15 in thickness and 100 in height, to lift a housing weighing about 2 kg. Does it exist?
Thank you!
Parallel of what kind: the door is overhanging and sliding or the door has a circular translational movement?
What energy is available?
What security is needed?
What is the size of the whole?
Available complete off-the-shelf, I don't think it exists.
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Seen from the side, the door has a downward and upward rotational movement while remaining vertical, seen from the front, an upward translation. A handle on the door allows it to be raised and lowered as long as it is stuck in the high position. The door is held in a paving stone 400 mm high, 300 mm long (front), 150 mm wide (sides where the closing system is attached), and a little less than 2 mm thick, it is a bent sheet metal.
So you just need 2 connecting rods and a small gas spring...
With 2 connecting rods the door turns , right? I need my door not to rotate on itself, it remains vertical straight during the movement (see diagram). I think I need a 4-bar mechanism to have 2 axes (the one attached to the door and the one on the fixed part) that remain parallel.
Hello
There is no schema in your present answer.
When I said 2 connecting rods, it is indeed per side to have a parallelogram.
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It looks like this in miniature is probably simpler, on this there is probably a system with a spring or other in it:
https://www.blum.com/fr/fr/products/liftsystems/aventos-hl/programme/
Ok 2 links per side, if I fix the 2 ends with the same distance between the 2 links it should keep the door straight during the movement, but then how can I size all this with mecha to do it in CAD first?
Thank you
The Blum system above all allows you to have a compact mechanism in position, with the hidden mechanism in the closed position.
If you have the same need, it's going to be complicated, you can go to Pinet (for example).
For the design, it depends on the environment (T°, dust), the desired rendering (agricultural or consumer design), if you manufacture on site, your manufacturing preferences (materials available).
Is it a personal (student?) or professional study?
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Professional, for the design I talk mainly about general mechanics, the calculation of the distances of the 4-axis system according to the initial/final position of the door and the position of my fixings (door and fixed part). The environment is -10° to 75° (machine that heats up a little), The rendering of the system is hidden and visible only when the door is open (like Blum), the material will probably be aluminum.
https://fr.wikipedia.org/wiki/M%C3%A9canisme_%C3%A0_quatre_barres
I have this to start with
4_barres.png
I don't do a lot of cinematics, for this kind of thing, I draw a sketch and by iteration (in general you can see quite quickly where to touch) I find the right system.
The wikipedia link is good, you draw the 2 positions of the door, the doorway, you know more or less where the pivot of the bars will be.
If you want the mechanism to be enclosed, it is likely that the upper link will have a "banana" shape.