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Questions tagged [machine-elements]

36 questions
24
votes
5 answers

Why exactly does a washer help distribute the stress around a bolt?

Usually the reason for having a washer under a bolt head is stated to be that it helps to evenly distribute the stress to the clamped material surface. But why is this? I would understand if the washer was significantly larger than the bolt head.…
S. Rotos
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What is the name of this particular mechanical linear position switch made of perforated spring strip?

I'm writing a few elementary paragraphs about switches and switch technology, and I cannot for the life of me remember what a particular kind is called, to give it an honorable mention. Here is a sketch of the switch in question: It is constructed…
Conrado
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2
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1 answer

Relation between links and pairs in Kinematic chain

I came across a equation for kinematic chain (for lower pairs only) : L = 2P-4 where L: Number of Links; P is the number of pairs how could this equation be derived ? EDIT: I tried putting values in the equation.Since for the pairs to be any integer…
Sankara Narayan
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2
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1 answer

Bending moment when there are no constraints

I faced this problem in an old book (Hall Allen S., Theory and Problems of Machine Design; 1961) The answer according to the book is 592 [in.lb], but I think the bending moment should be 0 because there are no constraints. Could anybody help me to…
Negarin
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2 answers

Is Smith Diagram and Modified Goodman Diagram the same? And how does one construct it?

I am confused about the names. Moreover, I haven't found any textbook which attempts to show step-by-step construction of these diagrams. I would be happy if anyone pointed to some textbooks or even YT videos. Thanks. EDIT 1: I was looking at this…
DunceDancer
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3 answers

Why actuators are mounted in inverted position?

Hope you are doing good. Can anyone please explain to me why actuators are mounted in inverted position on some excavators? Please see the image for better understanding of my question. Another question is, why on some excavators there is a mix of…
pj0909
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1 answer

What should be the thickness of machine tool bed?

I am developing Five-in-One machine tool which I did as a project working during 1984-85 in our Polytechnic college. Even though we made prototype at that time, now I want to make prototype for production version. It can be a cubical size of 1-1/2…
Paramasivan P N
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1 answer

How can I decrease strip tension with bridle rolls in tension leveller? How can I find total elongation after the strip exits initial bridle rolls?

I'm working on a tension leveller design which consists of 3 main sections. These are Input Bridle Rolls Zone: Increase the strip tension coming out of the decoiler. Leveller Zone: Strip goes through reversed bendings and gets plastically deformed…
Berkcem
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1 answer

What is the difference between sommerfield number and bearing characteristic number in bearing design?

After reading a few texts on the topic of sliding contact bearings I am confused between the bearing characteristic number and the sommerfield number. As per J.E shigley's text both bearing characteristic number and sommerfield number are same and…
Heatgunner
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A device to provide real-time proportional resistance to variable force

I'm considering a potential product but I'm not sure about the core technology I'd need. The fundamental idea is that there would be a cable (or something similar) that would be pulled. But as it was pulled with X force, the device (mechanically…
Alex Gold
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I need help identifying a special kind of coupling

I found this switchable coupling in Rollof/Matek machine elements, i have never seen this kind of coupling before. According to the dutch edition its name is: Tweevlakskoppeling Which literally means Two-surface coupling After some research on…
user14407
1
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4 answers

Jet Boat Engine Part Identification

If anyone can provide me information about this part right here, please tell me.
JIM G
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A particular planetary gearset

In the scheme there is a planetary gearset. I Know: Z1 = 102, Z2 = 11; Z3 = 13; Z4 = 19; Z5 = 152 and the angular velocity of gear 5 is 28 rad/s. I use the typical reletion: $ \frac{\omega _{5} - \omega _{p}}{\omega _{1} - \omega _{p}} = \prod \tau…
Deki 333
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I was solving fluctuating load problems and the word "static" confused me

Here's a snippet of the question that was asked a couple of years ago in university exam: A cantilever beam made of cold rolled steel for which ultimate tensile strength =540 MPa and Yield tensile strength = 360 Mpa. the expected reliability is 90%…
user47882
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1 answer

Removing chips from plastic threads

hello! I have this thread, in the middle… and it’s a bit hard to reach with tools. Do anyone have any tips to removing them without causing any damage to the surface or the thread for that matter
Mathias
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