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. L

    Exponential expansion and Higgs mechanism

    Our universe apparently has a positive cosmological constant so it will look more and more like de Sitter spacetime, expanding at at exponentially increasing rate. So eventually it seems that subatomic spacetime would be affected by this. Eventually even something a Planck distance away would...
  2. B

    Artillery Recoil Mechanism as Dual-Action Shock Absorber

    I've just viewed the National Geographic Channel's "Engineering Connections" program. specifically, the episode entitled "Airbus380", and that episode's discussion of the A380's landing gear shock absorbers, which used bicycle pumps filled with water to illustrate the basic principle of...
  3. C

    What is the underlying mechanism of nuclear decay?

    I think I understand the basics of the SM and know that the W and Z bosons are the mediators of the Weak Force. I also understand from chem the basics about nuclear stability (ratio of protons to neutrons, valley of stability/nuclear binding energy, etc.). What I'd like to know is what the...
  4. E

    Somebody explain railgun mechanism

    i am confused about the railguns electro-magnetic action please somebody explain if possible.
  5. R

    PH Scale: Understanding Its Mechanism

    What is the mechanism of pH scale?
  6. R

    What is the mechanism of small holes in auditorioms used as sound

    what is the mechanism of small holes in auditorioms used as sound absorbers
  7. K

    Does the Data Support the Proposed Reaction Mechanism?

    A chemical Reaction A-->B is carried out in a closed vessel. The following data are taken for the concentration of A, Ca (g/L), as a function of time, t(min), from the start of the reaction. A proposed reaction mechanism predicts that Ca and t should be related by the expression ln...
  8. Q

    What is the sealing mechanism of UHV view ports & electrical interconnects?

    Knife edges on the edges of flanges with a maleable material gasket like copper is often used for creating UHV chamber environments. For UHV view ports, typically say quartz or some other material, how is the UHV seal accomplished? Is it the same mechanism? E.g. knife edges machined on...
  9. J

    Gear mechanism and wheel arrangement for reduction of fuel consumption

    Hi everyone, I hope I have posted in the right place. I'm a commerce student and have absolutely no idea about mechanical stuffs. My father has an idea in mind which he would love to implement. He too is a commerce student. Hence, I need some help from you'll to see if this is really practical...
  10. F

    Conduction mechanism of SnO2 semiconductors

    Hello everybody and welcome to my first thread. I have read several publications regarding this compound, and found that SnO2 behaves as n-type semiconductor (Eg 3.6 eV) when oxygen vacancies are present. Very summarized and simply put, I understood that this lack of oxygen atoms enhance the...
  11. B

    Crank Slider Mechanism 3d movement question.

    Hi. This maybe common sense to some of you but I am racking my brain to find away to solve this one. I would like to pull a lever on one axis and move a slider on a different axis . So by pulling a lever towards me, I move a slider left and right. Is this possible without ball joints...
  12. S

    Need a mechanism for reciprocating motion

    I'm developing an automatic spray-paint shaking machine in order to achieve very well mixed paint for a big project. Since I'm using stone textured paint with lots of fibers and "Stuff" floating around in it, I'd like to go above and beyond in the shaking. Simply put, I want to roughly...
  13. S

    Mechanism behind electrically induced neuron firings?

    Electricity affect neurons. For example, in 1791 Galvani made the legs of a dead frog twitch by exposing them to a spark, and more recently in history, electric currents through the brain has been used to deliberately induce "therapeutic" epileptic seizures. What I wonder about is the exact...
  14. K

    Mechanism Geometry: Solving a Fixed Point Problem

    Not a homework question, but here seems the most revelant place for this kind of maths. I have a problem similar to a slider crank but not quite. http://imageshack.us/photo/my-images/851/sw1b.png/ Fixed points are A and B, all others are free to pivot. The beam labeled 20 is rotating...
  15. K

    Solving Mechanism Geometry Problem - A to B Rotation Degrees

    Ok, I have a problem similar to a slider crank but not quite. http://imageshack.us/photo/my-images/851/sw1b.png/ Fixed points are A and B, all others are free to pivot. The beam labeled 20 is rotating around, at this snapshot 40 degrees from vertical. How can I find how many degrees back...
  16. J

    Mechanism for Alcubierre engine?

    The theorized Alcubierre engine is purported to be capable of transporting a ship faster than the speed of light. I'm aware of the theory's problems associated with how much energy would be required to operate such an engine. This isn't my question. Apparently gravity waves, waves in the...
  17. S

    Mechanism for FTL information exchange.

    First, let me point out that this is probably wrong. Anytime I hear faster than light travel I am automatically skeptical. I just haven’t figured out why it’s wrong yet. Any ideas? 1. Two devices situated in between Bob and Alice produce two streams of entangled pairs of qubits. Each pair...
  18. R

    How to optimize this lever mechanism

    I have a friend who has a small workshop and he's looking to build a mechanism to help him burn the oil off metal parts(don't ask why, that's all he said and I could be bothered asking), So far he's got a decent gravity fed system that cleans the bearings and then passes them on to this...
  19. X

    Locking Mechanism for Overspeed Trip | 30N Weight

    I am working on a concept for an overspeed trip mechanism. I'm almost done with this except for this one thing: i need a locking mechanism that will hold a dead weight at a height so that this weight is only released only when the lock is actuated to realease it. But that's not all. When...
  20. N

    Deployment Mechanism to be tested on a meteorological balloon

    I want to perform a high altitude balloon experiment where I will be launching a payload onboard a meteorological balloon to demonstrate its feasilbilty and the fact that it works as a precursor to a cubesat mission. A cubesat is a very tiny satellite, usually weighing about 1kg which is usually...
  21. M

    Mechanism of combustion in limited oxygen

    I have read this in many places that carbon or any fuel for that matter example methane when undergoes combustion in limited supply of oxygen forms carbon monoxide as a major product. Could anyone explain me why this happens? I mean why can't the carbon atoms simply react with the required...
  22. U

    Organic: MacMillan Organocatalyast Mechanism

    Homework Statement I'm trying to figure out the mechanism for a reaction catalyzed by MacMillan Generation 1 and 2 organocatalysts. Not going so well. I don't understand what role the organocatalyst plays in the reaction. I read a paper about MacMillan and I think it was saying that the...
  23. L

    Static determinancy (lifting mechanism)

    Homework Statement http://img848.imageshack.us/img848/5884/screenshot20110425at121.png Uploaded with ImageShack.us Homework Equations Sum Horizontal forces = 0 Sum vertical forces = 0 Sum moments = 0 Sum Horizontal Forces=0 The Attempt at a Solution Dx-Ax+Bx+Cx=0 Dx-Ax+Bx+981 Sum Vertical...
  24. F

    Are there user-friendly mechanism design softwares available?

    I know you can make mechanisms using popular CAD softwares like Pro/ENGINEER but these packages are a bit too tough to learn and master. I wanted to know the names of any packages that are solely designed for mechanisms where you can design and run a mechanism easily without having to learn the...
  25. M

    What is Mechanism of DNA double from 1N to 2N

    what is Mechanism of DNA double from 1N to 2N ?
  26. Q

    Uncovering the Mechanism Behind a Mousetrap Car

    Hi all :) I have a physics project where we make a mousetrap car. Can someone explain to me what is the mechanism behind it and the advantages of using a mouse trap powered car? Thank you
  27. marcus

    Mechanism for Gammaray Bursts (computer sim shows neutron star merger works)

    http://arxiv.org/abs/1101.4298 The missing link: Merging neutron stars naturally produce jet-like structures and can power short Gamma-Ray Bursts Luciano Rezzolla, Bruno Giacomazzo, Luca Baiotti, Jonathan Granot, Chryssa Kouveliotou, Miguel A. Aloy (Submitted on 22 Jan 2011) "Short Gamma-Ray...
  28. J

    Type of mechanism is mounted on the living room?

    http://sbtvd.anadigi.zip.net/images/camara.JPG http://sbtvd.anadigi.zip.net/images/camara2.JPG A student walks into a room with a groove on the ceiling. Turning off the lights, he sees a shadow moving the floor. With only a ruler and a stopwatch, the student is able to determine what type of...
  29. M

    Propulsion mechanism of a ferris wheel

    How does a the propulsion mechanism of a ferris wheel propel the ride? A diagram would be helpful
  30. Z

    Mechanism of gravitational acceleration in GR

    I understand how non-euclidean space curvature can cause a change in direction of inertial motion but I don't understand how it can cause acceleration. I guess the reason will be that not only space is curved but also time and that the time curvature somehow will provide the energy needed...
  31. A

    2NH3->N2+3H2. Rate=k[NH3]/[H2], what is the mechanism?

    Homework Statement Ammonia decomposes to form nitrogen gas and hydrogen gas. The rate law for the reaction is Rate=k[NH3]/. Devise a plausible mechanism for this reaction, taking into account both the balanced equation and the rate law. Homework Equations Rate = k[NH3]/[H2] 2NH3->N2 +...
  32. B

    Slider crank mechanism mass moment of inertia

    I need help solving a mass moment of inertia for a slider crank mechanism. I've done my best to sketch it in the attachment. This will be used for sizing of a motor. Homework Statement Link A has mass Ma and is located Acg distance from its pivot point Z Link B has mass Mb and is located Bcg...
  33. Y

    Rope System With Stretching Mechanism

    I am working on a rope system with pulleys as you see in the picture. The diameter of the rope is about 1-2 mm. I am looking for a stretching mechanism for this system. Do you know any accessories that i can use here for this purpose? Note: Rope is made of stainless steel and the...
  34. arivero

    GIM mechanism and Z0 suppression?

    In what sense does the GIM mechanism implies the existence of a c quark? It seems that all that is required for Z0 suppression is to postulate that the mixed strange must be orthogonal to the mixed down quark.
  35. D

    Some help on correlating the reaction mechanism with the rate law

    Homework Statement Consider the following mechanism: (1) ClO^{-} (aq) + H2O (l) \Leftrightarrow HClO (aq) + OH^{-} (aq) [fast] (2) I^{-} (aq) + HClO (aq) \rightarrow HIO (aq) + Cl^{-} (aq) [slow] (3) OH^{-} (aq) + HIO (aq) \rightarrow H2O (l) + IO^{-} (aq) [fast] Is the mechanism...
  36. K

    Are there free software and recommended books for mechanism design?

    Hi guys, Are there any free mechanism design software's. I want to test whether a mechanism would a given work or not. It's preferably a 4 bar mechanism. Also can you suggest any good books for theory of mechanism design? Thank you in Advance.
  37. H

    Is this grignard preparation mechanism correct?

    [PLAIN]http://img443.imageshack.us/img443/6488/mechanisma1.png The magnesium transfers an electron to the C-X bond, yielding a Mg radical. The halogen atom leaves with 2 electrons from the bond and the carbon is converted into a radical. The negatively charged bromide ion forms an ionic bond...
  38. K

    Amino acid + HCl reaction and mechanism

    I was interested in knowing if my thoughts on this are right or if anyone else has any other thoughts on the reaction of any amino acid and concentrated HCl solution with water as the solvent; As an example of an amino acid such as cystine with an NH2 bonded to a carbon; I was thinking that...
  39. H

    What are the uses and limitations of transmission lines?

    "Transmission lines are specialized cables and other media designed to carry alternating current and electromagnetic waves of high frequency (radio frequency or higher), high enough that its wave nature must be taken into account. Transmission lines are used for purposes such as connecting...
  40. N

    Chymotrypsin Mechanism: Correct Steps for Enzymatic Catalysis

    what are the correct steps for the mechanism of chymotrypsin? Below is my answer but I don't know if it is right. a) His 57 catalyzes removal of H from Ser 195 hydroxyl. b. Ser 195's nucleophilic O attacks carbonyl C of substrate. c. His 57 donates H to N of sissile peptide bond...
  41. G

    Design an existing product with reciprocator mechanism

    I was assigned to design an existing product with reciprocator mechanism as shown below http://lh4.ggpht.com/_XzKHrOQkiyQ/SY8wIyYdKwI/AAAAAAAAAFM/uDbgweKFEX8/AutoCAD_2010_Reciprocator%5B5%5D.gif?imgmax=800 But i totally have no idea on it..Can someone please give me some advise?
  42. F

    Venetian Blind Locking Mechanism

    "Venetian Blind" Locking Mechanism First off, let me apologize if this thread is in the wrong location. Secondly, let me also say that I did search this forum and Google for quite some time before I posted. If I missed something, I apologize. Anyway, brass tacks. I've been thinking about...
  43. S

    Medical Mechanism for compensatory RESPIRATORY acidosis caused by metabolic alkalosis?

    mechanism for compensatory RESPIRATORY acidosis caused by metabolic alkalosis? I don't get it... someone please explain :(
  44. Saladsamurai

    Compact Notation of RxN Mechanism

    Hello all! I am reading through a combustion text and I am a little flustered by this notation: Am I correct in saying that the "coefficient matrices" {{\nu'_{ji}}} and {{\nu''_{ji}}} are not really "proper" matrices in the sense that there is not a vector that can multiply them that...
  45. Y

    Driver Car Seat Motion Mechanism

    Hi All, I'm working on a design of a seat for a simulator, the seat should include the motion mechanisms like the one in a car which Includes the slider, recliner, and the mechanism responsible for the vertical motion of the seat. So my question is I want to buy these mechanisms and...
  46. D

    Mechanism for reaction of Grignard reagent

    I am in an organic chemistry lab course and my lecture and lab do not align nicely. I need to write out the full mechanism for the reaction of malachite green and crystal violet dyes. The reaction starts by preparing a Grignard reagent from 4-bromo-N,N-dimethylaniline with magnesium/thf. The...
  47. S

    What are the mechanism implications of MECO?

    What are the mechanism implications of MECO? I have been reviewing observational anomalies associated with quasars and spiral galaxy morophology/evolution and thinking about the MECO hypothesis and its implications. I would be interested in eventually discussing them as a set however I am...
  48. M

    Can a Driven Oscillator Mechanism Enhance a Double Pendulum Hammer's Swing?

    The driven oscillator mechanism explains the swing of a child that drives it up higher. I am using the same mechanism with a double pendulum hammer. The hammer will increase its amplitude, and if so we have to stop it at its high point preventing it from flipping over. If we use a spring, it...
  49. A

    Explain GIM & FCNCs: Quark Gen, Cabbibo Suppression

    Can Anyone explain how the existence of more than one generation of quark means that flavour change neutral currents do not occour at tree level? How is a flavour changing neutral current deffined anyway? I understand that it has something to do with Cabbibo suppression
  50. DaveC426913

    Medical Mechanism of Diarrhea: Speed of Food Passage to Rectum

    I have a disagreement to resolve about diarrhea as a result of a food irritation or allergy (as opposed to flu or other) a short time (less than a couple of hours) after ingestion. 1] The food is basically liquified and passes out as diarrhrea. The food eaten is expelled as liquid within...
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