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Questions tagged [mechanisms]

262 questions
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3 answers

How do bike wheels keep turning when the rider stops pedalling?

I am very confused with something regarding bikes... How is it that a bike wheel continues to spin (either from momentum or from going downhill) when the rider is not pedalling, without also spinning the pedal? Similarly, what mechanism allows the…
Ankit
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1 answer

How is mechanism used in modern projector different from intermittent mechanism used in conventional one?

Do modern projector used for digital class works on same old conventional intermittent mechanism and blocking of light during change of frame. What is principal used in modern projector?
Rajakr
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6
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1 answer

What is this kind of bearing called

I came up with this concept for a partial rotation, lubricant free, low friction bearing for a robotics application. Two complementary sets of tensioned tendon-like cables (or tapes) serve both to constrain the degrees of freedom of the joint as…
jms
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6
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2 answers

Is there a mechanism that can turn circular motion into alternating circular motion?

I'm trying to power and agitator (alternating circularly back and fourth) with a crank. I've seen a bunch of complicated mechanisms that do this, but I'm looking for the mechanically simplest method.
user379468
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5
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6 answers

Mechanical mechanism that regulates gear's rotational velocity

Please do note that I am a civil engineer not a mechanical engineer. I have a gear that rotates at a speed that varies with time. Usually, it rotates at speeds higher than the desired speed. Is there a mechanical mechanism that can regulate the…
Abdulsalam_Musaad
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3 answers

Why does this thing that is not a screw have a screwdriver slot?

I am (partially) disassembling an old sewing machine to clean it up. While removing the bobbin winder, I found this thing that has a screwdriver slot, but it isn't a screw. This is the part: It came out of here: It is actually held in place by a…
JRE
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5
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4 answers

Rotation around an axis outside of the mechanism

I want to design a system of linkages that will allow me to rotate the green element around the blue point/axis without entering the red circle. The green triangle to go fully around the blue point. I only need about 120 degrees. I have seen…
Allshar
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5
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1 answer

Quick return mechanism for spring-loaded screw

I am looking for a way to convert rotary motion to linear, but it should take less energy to get back to initial position than when going from initial position to the end position. Specifically, a screw mechanism pushes a spring with multiple of…
PSz
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5
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3 answers

Rigid bumpers vs shock absorber bumpers

This question got into my mind when I am cleaning my motorcycle. If spring shock-absorbers like the one below absorbs shock from road imperfections, reducing strain in the motorcycle body as your drive, then why does car manufacturers use rigid…
Jem Eripol
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5
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2 answers

Is there a pressure relief mechanism that operates faster than sound in a material?

In the event of an explosion through a high pressure gas pipe, is there a way to vent the pressure wave, in order to protect downstream objects? The mechanism must be faster than sound; pressure relief valves and even rupture discs are actually too…
L. Jones
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1 answer

How does this pawl mechanism work?

From 507 mechanical movements, No. 63, we get the following diagram and description. Jumping or intermittent rotary motion, used for meters and revolution-counters. The drop and attached pawl, carried by a spring at the left, are lifted by pins…
Sam Gallagher
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4
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1 answer

How to trace a square with a reuleaux triangle

I am trying to trace a square (with rounded corners) using a reuleaux triangle and a single (circular rotation) motor. I've seen many animations (example) of this but do not understand how to make it. A diagram or geogebra file in the answer would…
Ankit
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4
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1 answer

How is linear motion achieved in this automatic blackboard eraser?

In the animation shown below what can be the mechanism used for this purpose? I know it can be achieved by using rack and pnion gear arrangement. But how are this set up arranged in classroom environment, I have no little idea. Please help me about…
Satya
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4
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1 answer

What is the reason for the intermittent motion and blocking of light during change of frame in Conventional projector?

Conventional Film projectors do not advance from one frame to another by continuous movement of the reels. What is the reason for the intermittent motion and blocking of light during change of frame in conventional film projector?what is the…
Rajakr
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4
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0 answers

How do these thread-holder mechanisms work?

In old scientific apparatus for electrical experiments, and more particularly in instruments such as galvanometers and torsion balances, we often need to hold one end of a thread in place. Examples include the following (particularly large photos…
Sam Gallagher
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