Mechanical Engineering: Ch 11: Friction (28 of 47) The Clamp: Ex. 1 (Part 1/2)
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- čas přidán 23. 01. 2017
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In this video I will find F=?, and W=?, on the block when a force of 400N is applied on a clamp.
Next video in this series can be seen at:
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Hey Michel, is W equal to the weight of two wooden blocks here? If not, then here is a confusion. If we try to loosen the screw, we must turn the handle anticlockwise, right?(According to previous lectures) But here, you are turning ckockwise🤔
I've been doing really well in statics so far but this section has got me in a mental pretzel... thank you for sharing!
Glad the videos are helpful.
upwards impending is gonna loosen the screw in a part, but it should tighten it as per (a) part. Please explain
You got me on that one.
Why does a higher screw radius lead to a lower force and lower mechanical advantage? That doesn't make sense to me.
The torque on the handle is converted to the thread of the bolt pushing the bolt forward. The larger the diameter of the bolt, the less of an advantage you get from the torque of the handle. (What if the diameter of the bolt was 30 cm?, would it be more difficult to turn the bolt?)
shouldnt the FBD diagram be in F coming from right to left
We didn't draw a FBD. Instead we used the standard technique of drawing a force triangle.
For part A why do you need to add lead angle and reaction angle? I'm having difficulty with when I need to add them or subtract the angle.
The angle theta is caused by the angle of the thread (like the angle of an inclined plane), the angle phi is caused by the friction, the greater the friction, the greater the force needed to turn the screw.
Hi there, may I ask what the difference is between the pitch of a screw and the lead of the screw?
The pitch is the distance from the crest of one thread to the crest of the adjacent thread. The lead is the distance from the crest of a thread to the crest of the thread after one complete rotation is made following the thread. For most screws it is the same distance, but for screws that have two separate threads on the screw (two starting points) the lead will be twice the pitch.
Thank you so much for responding, I didn't quite get it before and now I do, I'll take that into consideration in my calculations. Your videos have been a great help to me as I'm studying for my boards. I hope you keep up the excellent excellent work.
Shouldn't the direction of F be the other way(acting towards left) since you're trying to tighten the screw? The way it's drawn on the board seems like the screw is being loosened...
I think hes just following the way the screw diagram is usually drawn, with an incline upwards to the right, but otherwise the diagram would be mirrored to make the F go towards the left and the incline would rise to the left
Hi, Can you tell me why we are loosening the screw to tell how much the Force on the block is? If we are tightening the clamp, doesn't that mean that we're getting downward motion? But your FBD says we're having an upward motion. Kinda confused. Apreciate an answer.
Take a look at videos 25 and 26 in the playlist. That may clear it up.
Thank you for your answer. Is it because of the force Fp turning the screw clockwise and tightening it? That's how I understood it.
very helpful
Glad you think so!