Questions tagged [machine-elements]

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23
votes
5answers
5k views

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 ...
0
votes
0answers
36 views

Number of Kinematic Pairs

Kinematic pairs are the connection between 2 links that can have relative motion between them. But In six bar chain as shown below: There are five pairs for them to be a kinematic chain. But if I ...
2
votes
1answer
88 views

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 ...
0
votes
1answer
22 views

How to find a reference line for “ Form Tolerances”?

In my project I have to choose a form tolerances ( parallelism ) between the handle ( purple part ) and the part that sits inside it ( the grey part ), where the two parts slide on each other. But I ...
0
votes
1answer
55 views

What are the names of these connection mechanisms?

I've tried to search for the name of the connecting mechanisms on these clips but I can't find it. I'm trying to build something where two parts are connected on one axis (diameter less than 5 mm) but ...
1
vote
1answer
169 views

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 ...
0
votes
0answers
30 views

How to disassemble this eccentric bushing

This eccentric bushing: belongs to the hand crank of this machine: It cannot be seen clearly in the photo, but the small blocking bar inside the bushing is not hovering over but rather, is sunk into ...
0
votes
1answer
51 views

What is this strange nut and what to do with it

I bought a cheap version of this machine, because all decent ones had costs of hundreds of dollars of transport to my region. The machine seems to be made of solid parts, but is really badly assembled....
8
votes
2answers
137 views

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 ...
1
vote
1answer
67 views

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 ...
1
vote
0answers
67 views

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 ...
1
vote
1answer
43 views

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 ...
0
votes
2answers
244 views

What kind of mechanism can be used to rotate a part in 180 degrees (Ψ (yaw)) and 30degrees in 𝜃 (pitch) direction?

Let's say we have a flat object. We are asked to create some mechanism so that the part can rotate in the shown angles above. What mechanisms can be used?
0
votes
1answer
50 views

What are the different methods to join 2 parts so that one can rotate 180 degrees around the other?

Let's say we have one simple box and its bottom has been cut in a circular shape. We want to attach another box to this box that can rotate 180deg around the first one. What mechanism can be used to ...
0
votes
0answers
1k views

Bearing stress v/s crushing stress

What is "Bearing stress" and Is it different from Crushing stress? If yes explain How? and When does an element come under Bearing Stress? This question came to my mind while studying knuckle joint ...
1
vote
1answer
69 views

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 ...
2
votes
4answers
540 views

Jet Boat Engine Part Identification

If anyone can provide me information about this part right here, please tell me.