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. M

    Determining the loops in a mechanism

    how can we determine the loops in this mechanism.
  2. S

    Mechanism of Oobleck - Non-Newtonian Fluid

    Hi, What is the molecular-level mechanism of shear-thickening of oobleck (cornstarch-water paste)?
  3. K

    Your choice of least facepalm-able space travel mechanism

    Your choice of least "facepalm-able" space travel mechanism If I may use the "facepalm" meter of Sci-Fi hardness. Examples The film Gravity, in which only the astronauts in your audience would complain loudly about technical details such as how quickly Sandra took off her space suit, has an...
  4. W

    Will this work on moving mechanism

    There is an adjustable nut. Can it be used in moving mechanisms like robot?
  5. N

    Servo Mechanism to initiate movement of an electric motor trolley

    hey, So I am working on this project where I am trying to come up with a motor set up to drive two wheels of a trolley. The entire trolley weighs 650 kgs and i require a motor with a torque of about 400Nm. I want to set it up in such a way that i want to be able to apply very little force to...
  6. C

    Technical Drawing of Crank Mechanism

    Homework Statement Hey, I have to do my homework in Technical Drawing where we have to describe the function and the assembly of any part. I have got a crank mechanism and I just want to know if I name all the parts correctly. I am not quite sure if everything is correct. The Attempt at a...
  7. J

    Mechanism for a wheelchair exercise machine

    I'm looking for some advice for my final year project at university. My project is a design of an exercise machine for wheel chair users . The machine will look like a standard wheel chair but the wheels are a couple of centre meters off the floor. I want to add a mechanism to the wheels which...
  8. N

    What is the Wittig reaction mechanism?

    Can anyone please walk me through the mechanism as this question does not make sense to me. I do have some understanding of the general mechanism. The answer is B) but I don't understand how to get there. The confusing aspect to me, is the structure of the ylide.
  9. H

    Does the higgs mechanism explain the observed masses of sub particles?

    I was wondering if there are any theories that show how much mass the higgs field gives to each particle and why? I am specifically wondering about the observed masses for each particles rest mass. Does the higgs mechanism give mass in quanta, and if so is there a reason for the amounts?
  10. J

    Higgs mechanism and relativity

    Hi all, Having looked into the Higgs mechanism a bit (I am a physics undergrad, so my understanding is pretty basic if even correct), I have come up with a question. I understand that the way that the Higgs field gives mass to the W and Z bosons is different to the way that it gives leptons...
  11. T

    Mechanism by which mass curves space

    Hi everybody. This will be my first post here on PF. :) I'm wondering about the mechanism by which mass causes space to warp and curve within General Relativity. I did a cursory search on the subject and did come across some brief discussion here from a few years ago. At the time, the question...
  12. F

    Could Black Holes Be Baby Universes Evolving Backwards in Time?

    If seems to me that the conditions in the early universe which led to the activation of the Higgs field might be found inside a black hole, but in reverse. This might explain the mystery of infinite density inside a black hole, uniting Gen Rel and QM. Might a black hole then be a baby universe...
  13. K

    Higgs boson's mechanism for giving mass?

    What is the Higgs boson's mechanism for giving mass?
  14. E

    Unraveling the Pairing Mechanism in Cuprate Superconductors

    Hello everybody, this question is mainly addressed to people interested or involved in superconductivity. In the paper "Is there a glue in cuprate superconductors?" (Link - 2007) Anderson argues that the most important element to understand the pairing mechanism in cuprates is the proximity...
  15. S

    What caused the mechanism of Plate Tectonics to begin?

    Billions of years ago, something must have triggered rifts and the separation of the first landmasses into the first tectonic plates? Do we know what happened, when or how, and what Earth would have looked like at the time? Could water have played a part in this and to what degree? I'm...
  16. F

    Higgs Mechanism, how does it work?

    I'm not sure this thread belongs in this forum since we have now discovered a Higgs like boson. But I'm trying to get a better understanding of how the Higgs mechanism works. Let me share what I think I know, and you tell me how far off I am. Particles gain mass as they travel through the...
  17. L

    What mechanism causes the acceleration?

    If I were to hold a tennis ball out at arm's length, and release it, we all know it would fall due to gravitational attraction from the Earth's mass. In Newton's physics, gravity was a force that was created by and acted on all mass, causing two objects to accelerate toward one another, at a...
  18. F

    Mechanism of heating organic matter by radio waves

    I'm doing a study that involves radio waves passing through organic matter and have come across several sources that state that radio waves may heat organic matter when passing through it (For example: http://www.mobilfunkstudien.org/downloads/peleg_wm_10.5923.j.biophysics.20120201.01.pdf)...
  19. marellasunny

    Number of degrees of freedom of a double toggle mechanism for punching

    This is a mechanism used for crushing rocks/punching holes(when horizontal). When I use the Kutzbach criterion to find the number of degrees of freedom,I get 2. Is this because of the failure of Kutzbach criterion to recognize the geometry of the mechanism or did I go wrong somewhere? Kutzbach...
  20. siddharth23

    Mechanism suggestions for bringing down inclined cylinder

    Where I work, we use a single acting hydraulic cylinder to raise a tank filled with sludge. After emptying it, it has to be brought back to it's original horizontal postion. This is done using the weight of the cylinder and takes a lot of time (about 15-20 mins). Can you suggest something to...
  21. I

    Mechanism behind photon absorption and photon emission

    hi all, i learned that only certain orbits were allowed in the atom and that if the electrons occupied any of the orbits in between, that they would no longer be in a resonance orbit (i was taught that the allowed orbits were the electron probability wave in resonance and therefore no EM...
  22. marellasunny

    Which path does this mechanism follow?

    I found this mechanism(see image) in a very old book in the library.I was wondering if there is any mathematical technique(obviously geometrical) to find out the locus of travel that the links would take(case 1). Also, be able to calculate the displacements(case 2). The problem with the given...
  23. N

    Explaining Mechanism of Glucose Pentaacetate Reaction

    Homework Statement can anybody explain the mechanism of the reaction C6H12O6 +CH3COCl → CHO(CHOOCCH3)4CH2OOCCH3 glucose + acetyl chloride → glucose pentaacetate Homework Equations none The Attempt at a Solution I am thinking that the CH3COCl will split as CH3C+O and Cl-...
  24. C

    To find out the forces in a link mechanism

    Homework Statement The figure attached contains the link mechanicsm in static equilibrium. The forces F for the link 2 and Q has to be calculated. Given the length of link 2 is 4 cm and a moment of 50 Nm is applied to link 2 Homework Equations The Attempt at a Solution The attempt...
  25. S

    Cyclotron: Why Electric Field Inside Dees is Zero

    why electric field inside the dees of a cyclotron is zero
  26. pratikaman

    Real mechanism behind addition, subtraction, multiplication, division

    we all know the basic rules for operations of addition, subtraction, multiplication and division. but what i don't know is why these rules (of addition, subtraction, multiplication and division) works. as if we have been given algorithm to do these operations but not explained how they...
  27. R

    How does a vehicle's AWD system determine how to distribute power to each wheel?

    i was studying about four wheel drive/ all wheel drive and while studying about it i was just wondering how does your vehicle decide, to which wheel power should be transmitted more and to which one the power should be reduced, while cornering or while whee skidds.
  28. L

    Time Dilation: Exploring the Mechanism and Alternatives

    what is the exact mechanism by which time dilates for a fast moving object. Can the time dilation be explained by any other theory other than relativity.
  29. M

    How Do Magnets Generate Forces?

    Hi Is there an explanation of how,why a magnet create a force ?
  30. L

    Higgs mechanism and vacuum instability

    Does the shape of the Higgs potential change if the energy of the vacuum changes? According to Wikipedia, If a more stable vacuum state were able to arise, then existing particles and forces would no longer arise as they presently do. Different particles or forces would arise from (and be...
  31. M

    Position analysis of slider crank like mechanism using loop equations

    Hi Everyone, This is my first post so bare with me. Firstly, a bit of background about the problem. I am designing a near rear drive train for a formula student car which incorporates a chain tensioning device linking the differential to the rear of the chassis. Essentially I am wanting...
  32. G

    Help with windup/pull back toy mechanism floating gear placement

    Hi, I'm trying to design a windup baby toy (think toy stuck on wall rotating) with a gearing mechanism that works similar to a pull back toy car. Essentially I want to do a three quarter turn of the front of the unit anticlockwise to wind a coil spring via a gear train. When the front of the...
  33. S

    What is the mechanism of cooling?Mechanism of Cooling: Explained

    Hi all, I am not clear with the concept of "Cooling" a body.I know that the temperature of a body is the average kinetic energy of the molecules or atoms in the body.When heat energy is supplied,the molecules have more vibrations and hence the temperature increases.Let us have two bodies at...
  34. M

    Can a Lift and Rotate Mechanism Handle Heavy Duty Machining Needs?

    Hi all I need a bit of inspiration for a new CNC machining Fixture design. First the top of the fixture must be raised to get free of the guide pins, and then the top must rotate 120 degrees before it must be lowered over the guide pin again. I was looking for something like a rotary CNC...
  35. A

    Automotive Steer Wheels of Car 90 Degrees: Possible? How?

    can anybody tell me is it possible to steer the wheels of a car through 90 degree? if yes how?
  36. P

    Explanation of quadratic divergence in higgs mechanism

    Hi can anyone explain what a quadratic divergence is? and if so how it effects the mass of the scalar field i.e why m^2 = m^2_{0} + \delta m^2, why are these things squared? Also how would this divergence affect the standard model as a natural concept, because from reading books it would...
  37. T

    Auroral Mechanism: Questions Answered

    This video [http://www.youtube.com/watch?v=7Mz2laHjVoQ] explains the mechanism behind aurorae, but i need some clarifications: 1) Is it true that aurorae can be produced only by some ejecting chunks of plasma and NOT by solar wind (flow of particles)? If not true, then how solar wind can...
  38. G

    Guess the Mechanism help (Organic Chemistry)

    "Guess the Mechanism" help! (Organic Chemistry) Homework Statement After identifying my reactants and products via spectral analysis, I am now tasked with figuring out the mechanism behind converting a diol into a ketone. Homework Equations The Attempt at a Solution The key to this appears...
  39. M

    Mechanism for generating the energy in supernova

    In a type II supernova If I remember correctly the core of the star collapses and turns to a neutron star. The envelope then will accelerate towards the core. The energy then come from the release of the kinetic energy of the infalling particles as they are brought to an abrupt stop by the...
  40. A

    Automotive Steering Mechanism: Turning Front Wheels of 4 Wheeler

    can anybody tell me how to turn the front two wheels of an 4 wheeler in different angles by making small changes in conventional steering mechanism.
  41. P

    Help with mechanism choice please

    Hello, I hope you super-geniuses will please take a moment to point a layman in the right direction. If I can get past this sticking point I can complete the rest of this project myself. I need something small (tennis ball sized or smaller, smaller is better), lightweight, fast, electric, and...
  42. P

    How does the child safety lock on a drawer work?

    recently, i saw this drawer where you have to press something on a part of the drawer then you can take the things inside the drawer. if not, it is impossible to open the drawer. May I know what kind of mechanism is behind it? secondly anyone got any idea on how to design a mechanism that...
  43. N

    Finding the acceleration of a variable crank mechanism.

    I've attempted multiple times, but don't really know which way to go and none of them are getting to the answer. I've got the question (below), got it wrong and been told the correct answer. A variable crank mechanism consists of a slider in a slot which is rotated around an axis at constant...
  44. E

    How does a viscoelastic brake mechanism work for satellite deployment systems?

    Hello everybody! I imagined and prototyped this brake long ago for the deployment mechanisms of a satellite I never built. In essence, it's clean, it can work in vacuum and in a wide temperature range, and it can wait for long without maintenance, so other uses must be possible, like...
  45. P

    Can You Design a Mechanism that Translates Rotational Motion to Linear Motion?

    Designing Mechanism -- Updated Anyone got any idea on how to design a mechanism that… ◦Translates rotational motion (clockwise OR anti-clockwise) to linear motion ◦Linear motion ONLY to the right ◦Upon release, the mechanism returns to its initial state
  46. F

    Analysis of mechanism, DOF, repeated bonds of mechanism

    Analysis of mechanism, DOF, "repeated bonds" of mechanism Homework Statement The scheme is incomplete, nevertheless it is the way it is. It is required to determine the number of degrees of freedom for the given mechanism. Also, to find the number of "repeated bonds" (my english is poor) in...
  47. L

    Where does the O-O-H come from in this hydroboration-oxidation mechanism?

    I cannot for the life of me figure out where the O-O-H comes from that got added in the 3rd step! :confused: Here's image of the reaction mechanism: The H2O is not used until the last step and the H2O2 has already been used (except for the H+), so the other O that adds to the OH- to form...
  48. T

    Critique This Simple Faster Than Light Mechanism - Possible?

    Ok guys. Picture a bicycle wheel assembly apparatus with several gears and a giant wheel. The giant wheel is constructed in outer space such so that a person is placed on the outside rim of the wheel and then the wheel begins to be rotated at first slowly due to the torque required but then...
  49. E

    Should I Use a Level Winch Mechanism for My 370kg Load Project?

    Hi, I have been working on a project requiring me to lift a 370kg load through a height clearance of 30m. to do this, my team and I have designed for a frame and also utilising a winch system. the issue arises with the fleeting angle, which is the angle from the winch to the first sheave...
  50. B

    Geomagnetic Reversal 41k BP 240 years Paradox? Mechanism?

    There has been a series of papers recently published that provide observational data that indicates that something is cyclically abruptly changing the geomagnetic field. The rapidity of the observed geomagnetic field changes cannot be explained by a core based mechanism. There is no...
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