Mechanism Definition and 534 Threads

In engineering, a mechanism is a device that transforms input forces and movement into a desired set of output forces and movement. Mechanisms generally consist of moving components which may include:

Gears and gear trains;
Belts and chain drives;
Cams and followers;
Linkages;
Friction devices, such as brakes or clutches;
Structural components such as a frame, fasteners, bearings, springs, or lubricants;
Various machine elements, such as splines, pins, or keys.The German scientist Franz Reuleaux defines machine as "a combination of resistant bodies so arranged that by their means the mechanical forces of nature can be compelled to do work accompanied by certain determinate motion". In this context, his use of machine is generally interpreted to mean mechanism.
The combination of force and movement defines power, and a mechanism manages power to achieve a desired set of forces and movement.
A mechanism is usually a piece of a larger process, known as a mechanical system or machine. Sometimes an entire machine may be referred to as a mechanism; examples are the steering mechanism in a car, or the winding mechanism of a wristwatch.
However, typically, a set of multiple mechanisms is called a machine.

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  1. A

    External contracting block brake mechanism

    In the brake shown in the pic, what ll be the point of application of force to disengage the brake(it is holding type brake). It is an assignment problem in machine drawing class, I have calculated the shoe dimensions, but I have no idea where ll the force be applied to disengage the brake. And...
  2. S

    Mechanism of charge interaction?

    One of the core concepts in electric field theory is that charges exert a force on one another: a positive charge "pushes out," and a negative charges "pulls in." What is the mechanism by which charges interact with one another? How does one charge "feel" the presence of another?
  3. O

    What Is the Carbon Concentrating Mechanism in Photosynthesis?

    My first semester bio course is having us practice writing formal lab reports by doing some research through peer reviewed journals our university has access to and citing it in our paper. however something that keeps coming up in the papers I'm reading is something called "the carbon...
  4. A

    How Can I Improve a Latching Mechanism for an Aircraft Seat Armrest?

    Hi guys, I've been dropped in at the deep end at work, tasked with designing a latching mechanism for an armrest on a luxury aircraft seat - It has to work on a remote latch principle, ie by pushing a sprung-loaded button downwards to actuate a link arm via a pivot, which then retracts the...
  5. C

    How Does Electrophilic Addition Differ from Substitution in Aromatic Compounds?

    Homework Statement Show the complete mechanism for the electrophilic addition reaction of toluene and bromine, isopropylbenzene and bromine. Draw the structure of the intermediate hydrocarbon. Homework Equations None The Attempt at a Solution I am having a really hard time with...
  6. F

    Higgs mechanism and Angular momentum

    There is an aspect of the Higgs mechanism I am troubled about. This applies to any theory with Higgs, but for sake of definiteness I will restrict the discussion to the Standard Model. The (unbroken) theory starts with a complex Higgs doublet, which corresponds to four degrees of freedom...
  7. R

    What is the Mechanism of a Slurry Pump?

    hi guys I am working on a project which requires the transportation of microalgae. I was suggested to use slurry pump for the same. however I wanted to know its mechanism of functioning before jumping on to its purchase. I was not ble to find a satifactory reaponse to my query. I would be...
  8. R

    Mechanism with up and down movement?

    Hi ... I was trying to figure out a mechanism which allows for up and down movement. I figured a piston with crankshaft... anyone has any other possibilities? Thanks
  9. N

    Two-Step Mechanism: A + B -> D

    Hi, So if we have a two-step mechanism that goes something like this: 1) A + B -> C 2) C -> D ------------- A + B -> D and the second step is the slow step, the reaction rate would be r = k2[C] correct? Well, seeing as reactants A and B are zero order, varying their concentrations...
  10. S

    How Do You Solve This Organic Chemistry Mechanism Problem?

    ORGANIC CHEMISTRY II Homework Statement I spent hours trying to figure out how to do this mechanism but I always get stuck. Its tricky and will make you think.. think you can figure it out? Homework Equations Figure out the mechanism just using acid (H+) The Attempt at a...
  11. M

    Prototype 3-Wheeled Car Steering Mechanism

    hello all i'm creating a prototype for a 3 wheeled car ( 2 wheels at the back & 1 wheel in the front ) motor with the 2 wheels in the back i want to test its stability so i want it to move in a straight line then take a curve can someone suggest a simple mechanism for the steering (from the...
  12. E

    Ebook about the dynamic analysis of a bar mechanism?

    Do you know an ebook about the dynamic analysis of a bar mechanism?Thank you.
  13. C

    YSZ: Mechanism of Stabilizing Zirconia (Cubic Phase)

    Hi I wanted to know what is the exact mechanism of stabilizing Zirconia (cubic phase) by Yttria thanks :confused:
  14. D

    Exploring Trigger Mechanisms for Rubber Band Powered Vehicles

    I have a project that I'm working on involving a rubber band powered vehicle. I have a pretty well developed design involving several methods of propulsion but my main concern is a trigger mechanism in which to release this source of power from the rubber bands. Im not sure whether to go...
  15. R

    What Type of Motor Best Manages a Rotating Door Mechanism in Vending Machines?

    Hi all, i have faced a problem in the designing stage of a machine. I need to use a mechanism to close a door (very small metallic door of about 20 grams) for a period of time(this period can go up to 10 or more minutes) and then go back to its previous position in which another door is...
  16. N

    Higgs mechanism and gauge theory

    I'm an undergraduate in physics, I'm on my 2nd year. I have to write this assignment about the Higgs particle and gauge theory. There are quite some things that are unclear to me however. Since I'm only on my second year I don't know a lot of deep math like group theory, just basic stuff. I know...
  17. S

    How To Understand Ex3 Sum Mechanism?

    i need to implement a circuit that inputs two 4bit numbers (y3 y2 y1 y0 x3 x2 x1 x0) and it has an output of (c3 c2 c1 c0 s3 s2 s1 s0) where "c" is the carry and "s" is the sum i was given an example in which X=0101 (5) Y=1000 (8) and it outputs S=1010 (10) and C=0011 (3) 5+8=13...
  18. A

    Could it be that Higgs's boson does not exist, but Higgs mechanism does?

    Non-Higgs boson process of the generating of elementary particle masses in QFT As is known in the experiments on LEP and Bevatron, Higgs's bosons were not discovered. It is supposed that an energy amount bigger than 160 GeV is here needed. But some scientists doubt the detection of Higgs in...
  19. P

    Alkyl Halide Mechanism: E1 vs. E2 in Acidic and Basic Conditions

    This is my question... For the alkyl halide tell which mechanism, E1 or E2, will predominate under both stongly basic (with large base) conditions and strongly acidic. Tell if each reaction is expected to proceed relatively quickly, moderately, or slow (based on sterics for E2 and carbocation...
  20. M

    [Atomic] Searching for a Mechanism

    I did an experiment to calculate the cross section for capture, loss, and ionization for a 05+ projectile on an 02 target at 16, 24, and 32MeV. We used a tandem to produce the the beam, and a time of flight method (ToF) to determine the fragments. (We used the known Ne and He spectra as a...
  21. W

    Reaction Mechanism (Shouldn't Be Too Difficult)

    [SOLVED] Reaction Mechanism (Shouldn't Be Too Difficult) Homework Statement Write the equation for the overall reaction and identify any reaction intermediates: STEP 1: Cl2---> Cl + Cl STEP 2: Cl + CO---> COCl STEP 3: COCl + Cl2---> COCl2 + Cl Homework Equations See...
  22. A

    On spontaneous symmetry breaking and Higgs’s mechanism of mass production

    On spontaneous symmetry breaking and Higgs’s mechanism of mass production From lectures: L. Peak and K. Varvell. The Physics of the Standard Model. Full Lagrangian for fermion and photon Combine the gauge-invariant Lagrangian density describing a fermion field in the presence of an...
  23. J

    What drives spin alignment in some materials?

    The Ising model starts with an assumption that the nearby spins reach lower potential by pointing at the same direction. However, two magnets would reach lower potential by pointing at different directions. What is the mechanism, that in the first place makes spins attempt to align themselves in...
  24. B

    Higgs Mechanism: Does it Give Mass to All Particles?

    Hi there Lately, I have been irritated by some general articles about the Higgs Mechanism in newspapers. Those articles suggest that it gives mass to all particles (vector bosons + all fermions). However, if I read a textbook I can only extract from the context that it gives mass only to the...
  25. I

    Mechanism for self-unloading trucks (engineering question)

    I would like to know if it is possible to use the weight of a loaded truck to unload it, and if so by what kind of mechanism. Imagine a truck loaded with a shipping container. A "fork" (as in forklift but without the lift) is inserted in holes between the truck trailer and the container...
  26. rohanprabhu

    Rotation Mechanics [disk-axle mechanism]

    [SOLVED] Rotation Mechanics [disk-axle mechanism] Homework Statement Q. A disc is fixed at its center O and rotating with constant angular velocity \omega. There is a rod whose one end is connected at A on the disc and the other end is connected with a ring which can freely move along the...
  27. D

    Evolution of blood clotting mechanism

    I'm currently reading this article by Ken Miller on a plausible account of how the blood clotting mechanism in vertebrates might have evolved. There's some things I don't understand but which I hope someone here will explain to me: Here's the article...
  28. Ahmed Abdullah

    Understanding the mechanism of capillarity

    I can't convince myself that I understand the mechanism of capillarity- the rise and the drop of liquid level. For conveniene I am just talking about liquids that rises up liquids that form acute contact angle. Now Liquid molecules on the surface (in contact of gas) exert a force on the wall...
  29. S

    How does rubbing act as a mechanism for charge transfer.

    Homework Statement I don't understand why it is that by rubbing things together things develop charge, whereas when you just leave them close together they become discharged. What is it about the rubbing that acts as a mechanism to allow charge to flow? Isn't it the case that when rubbing...
  30. K

    Design a mechanism which knocks over can

    I really need help fast. I need to design a mechanism which has to be placed inside a can. The purpose of the mechanism is to knock the can over. I also have to have a 6 seconds delay before the can is to tip. I can use any kind of can thank you
  31. L

    Understanding the Higgs Field and Mechanism

    What is Higgs field? Some books say that because of this field the matter has the properties of mass but when I see arxiv I think it's something different. If Higgs particle is a boson then why this Higgs mechanism not considered a force?
  32. Ahmed Abdullah

    Understand the mechanism of capillarity

    I can't convince myself that I understand the mechanism of capillarity. Say the liquid is of that type that rises through a capillary tube. So it's contact angle should be an acute angle. Liquid molecules on the surface (in contact of gas) exert a force on the wall (of capilary tube) due to...
  33. T

    The Irony of the Higgs Mechanism: Giving Mass to the Massless?

    Forgive if I'm being sarcastic, but I just read on the Higgs mechanism, giving mass to the fermions and bosons. But at the same time, Higgs itself has mass? Isn't that abit irony?
  34. T

    Understanding the Higgs Mechanism

    Let me take an example. Suppose we have a Lagrangian, of a scalar field coupled to itself and a massless gauge boson field. Next, we expand the Lagrangian about the vacuum expectation value of the scalar field, and it turns out that, in the end, the gauge boson is massive. My question is...
  35. P

    Isobutylene Reacting w Cl2: Mechanism, Structure, Radioactive Carbon

    it was found that when isobutylene reacts with Cl_{2} under 0^{o}C in the absence of light it gives more methallyl chloride(3-chloro,2-methyl propene) than the addition product.bubbling oxygen through the reaction mixture doesn't affect the product formation. thsi reaction is carried with...
  36. N

    Implementation steering mechanism

    hey frnds ... i m 1st year student of DCE and m willing to make a car for college competitions. Till now i was using differential mechanism for turning the car but now i m interested to work on steering mechanism .. so can anyone suggest me how to implement steering mechanism ... :smile:
  37. A

    Constructing a Crank and Slotted Lever Mechanism in 3 Days

    hey i have got to make a scaled model of any mechanism that we see around(or maybe we don't sometimes) in the machine shop in under 3 days as our summer training project. we are provided with all the raw stuff and machines that one usually sees in machining shop. i have decided to make a crank...
  38. A

    Latching mechanism for a tilting ramp

    Hello all I have attcahed a WORD file that has a diagram that exlains the problem. When you open the file, you would see that I have a inclined part (called ramp) that pivots on a base. A ball (load) rolls up the ramp. The ramp is supported by a spring and some linkage. The linkage shown is...
  39. S

    How Does Mass Convert into Energy and Vice Versa Through Einstein's Equation?

    Homework Statement What is the exact mechanism through which mass converts into energy and vice versa through Einstein's equation.In other words,what are the conditions under which this transformation happens and why?Homework Equations E=m.c^2The Attempt at a Solution Some argue that mass is...
  40. Ahmed Abdullah

    Why must the hydrogen in E2 reactions be anti- and planar to the leaving group?

    In the presence of polar, non-protic solvents (i.e., DMSO or DMF), alkyl halides undergo reaction with bases to generate alkenes by an E2 mechanism. In the E2 reaction, the proton removed by the base must be anti- to the leaving group, and they must also be periplanar (the hydrogen, the leaving...
  41. A

    How Do Curly Arrows Illustrate Electron Movement in Acid Rain Formation?

    Homework Statement I have been working at this for about two days now and haven't really gotten any further. Unfortunately my teacher is away but last time he checked it over he said I was 'almost there' so a few extra nudges in the right direction would be appreciated! I'm trying to write...
  42. DaveC426913

    Thinking caps on : telescoping mechanism

    I'd like some help from builders - modellers or mechanical tinkerers. I'm trying to build the skeletons of some polyhedra - the vertices are intersections of rods - no faces. http://www.reed.edu/~mcphailb/puzzles/images/hex.bmp" I want to be able to telescope the rods by about 3x. So, I...
  43. S

    What Went Wrong with My Straight Line Mechanism Design?

    I've calculated a straight line mechanism for a 15cm straight line... 39% straightness over the cycle... lengths came out to L1 = 10.35cm L2 = 4.14cm L3 = 13.445 = L4 these values should give a 15cm line... so I went to go build the thing.. all the distances from each hole on...
  44. Q

    Derive a rate law from a mechanism (rates of reactions)

    Homework Statement The reaction: CO + Cl <-> COCl2 has the rate law: rate = k[CO][Cl2]^(3/2) Show that this rate law is consistent with the mechanism: Cl2 <-> 2Cl (fast) Cl + CO <-> COCl (fast) Cl2 + COCl -> COCl2 + Cl (slow) (i don't know how to do superscript and subscript on...
  45. H

    Subatomic mechanism of heat transfer by convection?

    Hey. I've been pondering on and off for a while now how exactly energy is transferred between two gas atoms, with different energies, via collision. Specifically how the electrons, photons, neutrons, protons, and any other particles that are used for energy transfer in convection, interact...
  46. Monique

    Understanding Meiotic Drive and Non-Random Segregation

    "Meiotic spindle asymmetry and functional differences between the centromeres of homologous chromosomes and recombinant/nonrecombinant chromatids have been shown to result in non-random segregation during meiosis (meiotic drive)". Does anyone know how this works? How would one chromosome be...
  47. H

    What is the Role of Chlorine in KCl Injection Mechanism?

    Ok so I know with the injection of potassium chloride, the potassium in the extracellular fluid works to inhibit any repolarization, by increasing the amount of K in the extracellular fluid (hence not allowing EPSPs to reach threshold and trigger Na channels for an action potential), however...
  48. O

    Mechanism allowing a blade to cut through tissue?

    Here is a question posed to me recently that I'd like to post for discussion. It has elements of biology and physics. A butter knife does a poor job of cutting through a tomato or your hand, whereas a razor sharp knife cuts through quite easily. Why is this so? What mechanism is at work at...
  49. A

    Find Answer: How Does a Fan Work?

    can anybody help me to find the answer of this question? a fan ( or a propellor) rotates sidewise, but the air goes making a perpendicular with the axis of its motion.. I know that there is vector involved in this, but how does it work?
  50. C

    2 Simple mechanism geometry problems

    It's obviously been a while since I've worked some of these problems, and I thought I got it, but then something is tripping me up on each of these: 1) Rocket is fired vertically and tracked by radar--obtain an expression that relates the altitude and the horizontal distance between it and...
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