Machine Parts - Relating technical mechanics to the mechanics

[Femme_physics]

Homework Statement

Can anyone explain to me how is the left-sided drawing related to the right sided drawing? I asked the teacher but he confused me so I let it go.

http://img443.imageshack.us/img443/3036/drawinge.jpg

The description is this:

This crane in the drawing is designed to lift load at max weight of 650kg through the described hook construct. The screw in the drawing is fastened by a force that prevents any relative sliding possibiltiy betwee the two surfaces.

The questions just want me to pick a right screw and right I profile for the beam, but I'm not trying to solve it. I'm trying to figure out how do the two drawings relate.

 

[I like Serena]

Hey Fp!

Seems to me the left drawing is an enlargement of just point B, where the weight is attached.

 

[Femme_physics]

Hi ILS!

Hey Fp!

Seems to me the left drawing is an enlargement of just point B, where the weight is attached.

Oh, simpler than I thought! Thanks :)

OK but then there is this question. Is this also an enlargement of a point?

http://img402.imageshack.us/img402/4981/drawingsss.jpg

The structure in the drawing is made out of beams with a profile of 200x100x10, and connected to the wall at point A, C. At point B acts force F of 500 [kN]. Angle alpha is 30 degrees. The structure is welded to the wall at point A through 3 welded sutures, as described.

 

[I like Serena]

Yes, it appears to be an enlargement of point A.

 

[Femme_physics]

But point A is not marked in the other drawings, how am I supposed to know where it is?

 

[I like Serena]

In your text it says "The structure is welded to the wall at point A through 3 welded sutures, as described."

That means that an enlargement of point A should show 3 sutures, which is what the left drawing shows.

As for scale, the distances in the drawing are up to 200.
I am assuming that is millimeters, so that is 20 cm.

The weight is 500 kN, which is equivalent to 50000 kg. Say a stack of 50 cars.
To be able to support such a weight, I'd expect that the point where it's welded would at least be 20 centimeters...

 

[Femme_physics]

Finally got it :) How can I not? When ILS is in the hood!

And yes it does seem like an awful lot of weight... but this is what the question says!

 

[I like Serena]

Good! ;)

So are you designing equipment now that hauls weight like that?

 

[Femme_physics]

Hehe, no, but I did design a lifting device; namely jackscrew, for this course (purely via solidworks) But it was just following up instructions, so wasn't an original design. If it was an original design I'd probably make a transformer to do the lifting! (muwahaha :) )

 

[I like Serena]

Hohoho, that's a design that I'd like to see!

 

[Femme_physics]

OK, how do these relate?http://img829.imageshack.us/img829/7550/metaem.jpg

A fitting is connected to profile U200 with a 6mm weld as shown in the drawing. On the fittng acts a horizontal force of 50kN

 

[I like Serena]

They are exactly the same.
If you look at the first from the left, you'll see the second.

The horizontal bar in the first drawing is a cylinder.
It matches the hole in the second drawing where you are looking into the cylinder.

 

[Femme_physics]

Funny how you were able to relate them, to me the left one looks like a bench (that you look at from behind...right?). And the the right one just looks like a bearing! But, if you say so, I'll go ahead and trust you! :)

 

[I like Serena]

I checked the measurements and saw they are the same scale.

Furthermore, the top and bottom of both drawings are aligned, suggesting they are different horizontal views of the same object.

When you lean back on your bench you'll have an uncomfortable cylinder in your back.

 

[Femme_physics]

Hah, touche!

Well I'll be damned, I got to start using my head more... thanks!