mechanical calculations for custom made hinges 1

[AR1958]

dear's
kindly, i need your help for the calculation of the attached fig.
the door weight is 5 KG, the weight of each hinge 350 gram.
the size of the hinge is 100 mm from center to center
the distance in the box for the hinge is 40 mm from center to the edge
the fixed washer in the box height is 23 mm
the axles are M 10 SS bolts (10 mm)
all materials are in SS 316 grade
your quick response is highly appreciated

thanks on advance

Arafat

 

[MikeHalloran]

If all materials are SS, you can't reliably calculate the operating loads because of all the galling.

Knowing the weight of something is useless unless you know where the gravity vector is.
Which way is up?

I'll ignore the weight/mass confusion for now.
Boxes are usually full of something at some point in their lives.
What might it be full of?
Will the box ever be positioned so that the weight of the contents bears on the door?
What holds the door closed then?



Mike Halloran
Pembroke Pines, FL, USA

 

[AR1958]

the box will hold a drinking water,but ignore the box weight, the door is fixed horizontally and it is weigh 5 Kg and the door size is
610 mm X 166 mm

 

[Jboggs]

You said you need help with calculation, but you didn't say what calculation you need. Motion geometry? Material thickness? Forces and moments? Load capacity? What is your question?

 

[AR1958]

Forces and moments and Load capacity for the hinges.
Thanks

 

[rb1957]

the two links are supporting only the weight of the lid ? can you draw a FBD ?

all this SS makes me think there's something going on that we're not being told ...
what are those two "propeller" type things (that'll be inside the box when the lid's on) ?
does it get hot ?

the devil is in the details ...
how tight at the bolts in the holes ? (I hope it's a sloppy fit, 'cause there doesn't look to be much adjustment)
is there a bushing in the holes ? (so that the hinges are not being tightened up against each other)
how much moment do you expect at a hinge ?
do you seriously think that (multiple) 1/4" thk SS lug will have difficulties with 5.7kg ? (if that is the load) ... "PBI"

another day in paradise, or is paradise one day closer ?

 

[racookpe1978]

I think the two "propeller things" are his clamps to lock the cover down.

I am assuming that the "lid" is on the top, and his sideways view is rotated 90 degrees => Door/lid is on top, the two handles are to hold it closed (maybe by twisting under the complex folds just under the joint?).
No external handles or any way to lift the thing - gonna be heavy if filled with water, but 5,700 kg? That's more water than the box can hold.
Now, if the L-brackets are the hinges, then they need to be supported 2-3 inches away from the side somehow.

 

[rb1957]

he says "5 kg" not "5000kg" ... yes?
or are you using a "European" comma = decimal point ?
but then <6 kg of water isn't much volume ...

another day in paradise, or is paradise one day closer ?

 

[racookpe1978]

Hmmmn. Door weight was 5 kg - which seems a bit low: I recently finished a 50 x 18 gun locker with a 1/4 inch plate door that weighed 52 lbs. I used (with advice from the forum here) two spring-assist, air pressurized lift rods to hold it up while open, prevent slamming (closing) even if near-horizontal when closing)

 

[rb1957]

yes, but this door is 2' x 6" x 0.04" (1mm thk?) ... to get 5kg I need thick = 1/4" (6mm)

another day in paradise, or is paradise one day closer ?

 

[tbuelna]

The one thing that seems like the limiting factor in this design is how the two 10mm hinge bolts are attached to the end panels of the box. I would assume they use some form of threaded connection to permit assembly of the hinges?

 

[BUGGAR]

And don't forget the most basic of loadings: "If it sticks out from the wall and someone can sit on it, then at least two large people will find a way to sit on it together."

 

[chicopee]

I would explore the areas where the two 10mm bolts penetrate the side walls of the box. Either beef up the wall thickness or internally weld bosses having internal threads for the two bolts. Calculations involving torsion and bending on the bolts will probably reveal adequacy in the design since you are only dealing with a 5 kg lid, however, there are factors that you can not take into account such as rough handling, therefore, beefing up the area that I mentioned would be prudent. As a matter of fact a similar bracket arrangement as show on the lid would be one of my choices.