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.

View More On Wikipedia.org
Recent contents Top users
  1. I

    Mechanism that causes tension and normal force?

    Homework Statement What is a mechanism that might cause a rubber band or a string to develop tension in response to a force that you apply? What mechanism explains how walls and tables exert normal forces without bending noticeably? Homework Equations None, since this is a...
  2. D

    What is the mechanism that transmits force?

    Hello all, New to this forum. Have had an interest in physics for a long time and studied it for a while at undergraduate level. Anyway, my question is this: What is the mechanism which actually transmits force? I'm thinking about electric or magnetic force. When two objects are...
  3. S

    Scissor mechanism: static analysis

    Hi all, I have this mechanism and I have to calcutate the spring applied by the spring to stand the force F. I have done a simple analysis but unfortunately it's wrong since I get the system is never in equilibrium. http://imageshack.us/photo/my-images/651/scissor2.jpg/ Would...
  4. D

    Mechanism and Rate Law of Cl2 Reaction: Find the Answer

    Homework Statement The proposed mechanism for a reaction is Cl2 => 2 Cl (Fast) Cl + H2S => HCl + HS (Slow) Cl + HS => HCl + S (Fast) Which of the following would be a rate law for the reaction? The Attempt at a Solution From other questions I've done the rate law for the...
  5. S

    Mechanism of the cosmological redshift

    Hello, I have read that `cosmological redshift` means a photon is being `stretched`by space dilation and thus gets to have `longer wavelength` I am unsure if this is true and if yes, why is it true Many thanks
  6. ShayanJ

    Understanding Higgs Mechanism & Its Impact on Particle Mass

    I want to gain an understanding of Higgs mechanism I know I can't understand it precisely without knowing enough group theory,representation theory and etc. but I just want to have sth like a chronologically ordered list of what happens that separates EM and weak interactions and gives...
  7. P

    What is the oxidation mechanism of KMnO4 on alkanes?

    Hi, I've been searching for the oxidation mechanism of KMnO4 on alkanes (aryl derivatives like toluene). All I found was some web sites telling me the overall reaction and that the mechanism is either unimportant or too complicated for their purposes. I found some little notes that it has a...
  8. A

    What is q (the charge) in higgs mechanism?

    what is "q" (the charge) in higgs mechanism? hi, does anybody know what kind of charge the "q" stand for in the higgs mechanism? I mean the mechanism between the weak force mediators: W & Z, and the higgs boson, which leads to them acquiring mass. I've learned about it from the...
  9. N

    New Theory: from Superfluids to Higgs mechanism

    Theorem unifies superfluids and other weird materials http://newscenter.berkeley.edu/2012/06/08/theorem-unifies-superfluids-and-other-weird-materials/ Nambu Goldstone bosons...of the Higgs Mechanism!..and phonons...from Cosmology to materials design. “Surprisingly, the implications of...
  10. A

    How does the Higgs mechanism explain the origin of mass in particles?

    Hi, As I understand, please correct me if I'm wrong, when a subatomic particle interacts with the Higgs field it generates mass due to the higgs mechanism. Does this have anything to do with with e = mc2? (I'm not too privy to particle physics or relativity.) Suppose an electron and a...
  11. TrickyDicky

    Is the Higgs mechanism really a spontaneous symmetry breaking?

    The Higgs mechanism is often explained (both here at PF and in many physics sites including wikipedia) as an example of spontaneous symmetry breaking, but the Nobel winner physicist 't Hooft says in his "for laymen" book about particle physics, "In search of the ultimate building blocks", that...
  12. P

    The Higgs mechanism and the Beginning of the Universe

    The Higgs mechanism and the Beginning of the Universe Now that the excitement about the discovery of the Higgs particle has made the Higgs mechanism justly famous, could someone please clarify for me the implications of incorporating this component of the Standard Model of Particle Physics...
  13. R

    Mechanism of high-temp. superconductors

    My prof. asked: "What is the mechanism that causes certain materials to exhibit superconductivity at temperatures much higher than around 25 kelvin?" then until now it remain a question to me?.. so anyone have an idea? thank you.
  14. P

    Help with designing an electron accelerating mechanism

    ion accelerating source setup I'm currently building a rectified, filtered power supply for use as an ion accelerator. The setup is attached as a JPEG. I am wondering how/where I can add resistors to the arrangement to make it so that when the dielectric breakdown voltage is between the...
  15. R

    Looking for alternative to a spring mechanism

    Hey! I'm trying to find a more cost efficient alternative to a spring for a design that I'm working on. Basically, I'm designing a tile that you step on and drops about an inch and then comes back up when you step off. I have been researching and trying to find springs to use, but my cost is...
  16. B

    QED vs Higgs: Mass of Electrons and More

    I understand that an electron gets its mass by self-interaction of its fields which is explained by QED, but on the other hand there is the higgs mechanism which gives mass to all the fundamental particles. Does the electron have two types of mass one which is due to the QED mechanism and the...
  17. E

    Mass, Gravity and the Higgs Mechanism

    I am led to believe that while the Higgs Mechanism is now almost certainly the explanation for mass, it gives no insight whatsoever into gravity. I really really hope that I am incorrect. There's got to be some speculation out there. What do the boson and the field have to do with gravity...
  18. B

    How can Higgs mechanism and gravitation coexist?

    After having read a number of articles about the potential discovery of the Higgs boson at CERN, I am wondering how the "mass effect" generation by the Higgs mechanism can coexist with gravitation as gravitation has been since Newton tightly coupled with the concept of mass. I develop below...
  19. M

    Light, Secure Board Clamping Without Screws

    Hey basically I'm trying to find a light and small mechanism that is able to clamp up/fasten two board/plank together in a simple way without the use of screws. I'm trying to connect an acrylic board with the right suitable size on the base of the design. Do anyone have a thought on this? I have...
  20. I

    How can I create a mechanism for precise linear motion in two planes?

    Hey guys, I'm brainstorming some ideas for a mechanism that will be able to move an object in the vertical plane up and down, as well as left to right. Essentially I'm looking at controlling the X and Y coordinates of this moving mass. I want to be able to move in the vertical plane, lock it...
  21. J

    Thermodynamics of the Higg's Mechanism

    As I was taught in my modern physics class the Higg's Field acts like an ideal ferromagnet cooling down to some constant and thus invoking spontaneous symmetry breaking. The process of the Higg's Field cooling down is modeled by the Mexican Hat Potential. What I do not understand about the...
  22. T

    Solving Timing Mechanism for C & Arduino Water Sensor

    I'm using arduino to make a water sensor. The sensor needs to go off after a certain period of time of not having come into contact with any water. The difficulty is that i can't use a delay() mechanism as it would mess with other functions of the sensor. I had thought i found a solution but i...
  23. S

    Suitable mechanism for changing the angle of attack of an airfoil

    I have to conduct wind tunnel test on a naca0015 symmetric airfoil at different angles of attack and I am in search of a suitable mechanism to change the angle of attack of the airfoil.Please help.
  24. C

    Does an O Chem I and II Rxn Mechanism Bible exist?

    I start Organic II in the fall. I'm looking for a place that has O Chem I and II reaction mechanisms with arrow pushing shown. Yes, I'm lazy and don't want to make more note cards. I apologize if I was unable to find it with the search function.
  25. G

    Can a truss with released ends still form a mechanism?

    Dear all! I have encountered a problem with modelling a truss. When modelling on an analysis software, you must release the ends of the joints, but not all or it will form a mechanism, therefore you release all but one of the joint. But what I have here, is a truss that is released on all ends...
  26. H

    Wiper screen wiper mechanism calculations

    Homework Statement In a high school project we have been given the assignment to design the mechanism to transform the a rotary motion into the oscillating of a wiper blade. I'm a bit confused as to how to go about the problem.. I have been given that there is a closing force between the...
  27. B

    M-nitroacetophenone to m-aminoacetophenone reaction mechanism.

    I have this reaction mechanism but I am not sure if its correct or not. In lab we reduced the m-nitroacetophenone using tin and HCl and then using sodium hydroxide to make m-aminoacetophenone. This mechanism goes beyond the scope of our class and not sure why our lab teacher had us do it and its...
  28. S

    Mechanism of Bond Energy Absorption

    When scientists analyze proteins (chains of amino acids), often times light spectroscopy is used. Light is passes through a cuvet containing dissolved protein, and the absorption is measured. My question is: How do bonds absorb energy? What is the actual mechanism? I have been told that the...
  29. O

    Fluid Flow Analysis of Howitzer Recoil Mechanism

    I'm looking to do a fluid flow analysis on the recoil mechanism of a howitzer. The analysis will involve simulating oil flowing through some complex orifice profiles. There will be 2 fluids (oil & nitrogen) in different parts of the recoil mechanism. The results I would like from the...
  30. K

    Is thermodynamics a description rather than a mechanism?

    It seems to me that it should be. For example, some systems do not have a well-defined temperature. How do you use laws of physics depending on temperature (such as the law of thermodynamics) when you have a system that doesn't have a well-defined temperature? How do you even go about discussing...
  31. B

    Slider crank mechanism. Help needed to find the velocity & angular velocity.

    Homework Statement The instantaneous configuration of a slider crank mechanism has a crank GH 10cm long, the connecting rod HP is 50cm. The crank makes an angle of 60 degree with the inner dead centre position and is rotating at 110 rev/min. Determine the velocity of the piston P and the...
  32. J

    Mechanism for matter creation in an expanding Universe?

    Hi, I wonder what people think of the following mechanism for matter creation in an expanding Universe. Imagine a particle-antiparticle pair coming into existence from the vacuum. As I understand it, they will annihilate each other in the time that a light signal takes to travel from one...
  33. A

    A puzzle about the higgs mechanism

    I might misunderstand the higgs mechanism. And I have a puzzle. Consider an electron in an accelerater. It is massive at low energy and its speed is something lower than the speed of light. However when it is accelerated to the electroweak scale, su(2) becomes unbroken and the electron turns...
  34. L

    What is the actual 'mechanism' of friction

    in mechanics and physics we are forever talking about friction and using it to solve problems. but what actually is friction? is it as simple as saying how rough a surface is? that doesn't sound adequate to me. if that were the case then i'd expect all materials to have the same...
  35. S

    Problem with rope climbing mechanism

    Hi, I need to figure out how to design a device that should climb on a rope without any electrical or chemical plant (see the attached file for drawing). I need a good idea how to generate sufficient lifting force in order to compensate weight and friction?
  36. strangerep

    Neurological mechanism for perceiving time?

    Hi all, I'm a first time poster in Biology, and I'm not sure if this question belongs in Biology or Medicine. (I normally hang out over in quantum physics.) What is currently known about the detailed neurological/biological mechanism by which humans perceive the passage of time? Simple...
  37. V

    Snapshot and history graphs for a string under tension (drive mechanism)

    Homework Statement A string with mass density u = 9.00 g/m extends from zero to infinity along the x-axis. It is under tension T = 25 N, and is driven by a mechanism at x = 0. The velocity of the drive mechanism depends on time as: vy(t) = 0 (if t = 0) 10.0 cm/s (if 0 < t ≤ 0.1 s)...
  38. Femme_physics

    How Effective Is Chebyshev's Linkage for Precision in Gripper Mechanisms?

    So we need to make a gripper in Solidworks only for this object http://img819.imageshack.us/img819/2285/thepart.jpg Our current goal (as per our professor) is to focus on our gripper mechanism. My classmate suggested the following for the gripper final grip mechanism...
  39. C

    Mechanism for self mode locking in Ti:sapphire

    I am a PHD student doing research on Ti:sapphire lasers so that when I enter the lab I have a full understanding of workings of the laser. I was wondering if anyone could go over the finer points of the mechanism of self mode locking in a Ti:sapphire laser? I have a picture in my head that...
  40. S

    Question on quantum entanglement mechanism

    Hello, I can understand only the basic principle behind quantum entanglement. Do you guys know of the mechanism by which it works? I understand that there is no information being transferred between particles that react under entanglement. So what then is the hypotheses as to how one particle...
  41. A

    What is the rate law for the Eigen-Wilkins reaction mechanism?

    Hi, Can anyone help derive the rate law for the Eigen wilkins reaction mechanism? The derivation in the wikipedia entry (http://en.wikipedia.org/wiki/Eigen-Wilkins_Mechanism) is confusing, but the rate law is correct. I can't figure out if they make a "steady-state" approximation or a...
  42. J

    A mechanism for Mach's Principle?

    Hi, How about this for a sketch of the mechanism of Mach's principle? For the sake of argument let us assume that gravitational waves behave in an analogous way to electromagnetic waves. Let us also assume that the masses in the rest of the Universe are rigidly fixed. I apply a force to...
  43. M

    Simple mechanism design software

    Hey, I just started a course in mechanism design this semester and I was wondering if there was a free/inexpensive piece of software that would allow me to simulate/analyze simple mechanisms including linkages, joints, and such. Perhaps there might also be some sort of java applet on the web...
  44. S

    Controlled Spring Like Mechanism

    I have a need for a mechanism that acts juust like a spring (I pull, load it up, and when i let go it pulls away and returns to its normal length), but doesn't snap back like a spring. I have experiemented with automatic door closers, but they are definatly not the answer (require too much...
  45. C

    Molecular machinery - Mechanism of action?

    I'm watching a fascinating video about DNA replication: Can someone explain briefly what the mechanism of action (and locomotion) is for all these little machines? Is it simply electric potential (due to ionization?) ? Thanks
  46. S

    Pneumatic actuators - locking mechanism?

    The problem: I was planning on using pneumatic linear actuators for a deflector - to direct the material from a conveyor, correctly down the chute - and i needed the deflector to be adjustable. The deflector itself is made out of chromium carbide clad plate, it will weigh atleast 100 kilos or...
  47. H

    Calculating Torque of a Crank Mechanism

    Hi, Im currently designing a small machine which uses a simple crank mechanism but my crank mechanism is not a typical one. My application: [/URL] My application uses the crank wheel to drive the block (10kg). Hence, I need to calculate the torque require to drive the crank wheel. So I can...
  48. A

    Ketosis/Ketoacidosis Reaction Mechanism?

    I'm in a first year organic chemistry class with a biochem focus and I am going to do a project on ketoacidosis. While I can find the pathway online, since this is an organic chemistry class, I figure that a reaction mechanism that illustrates electron movement (arrows and such) would be...
  49. R

    Is a Rack and Pinion Arrangement Suitable for an RC Car Steering Mechanism?

    hello guys..i'm trying to make my first rc car..but m not getting the steering mechanism for it..is the steering mechanism for real cars applicable on it..?:confused::mad::rolleyes:
  50. M

    Control of Cell Size / Mechanism of Hypertrophy

    How are cell membranes enlarged? What is known about how this process is controlled? How might I read more about this topic? I am mainly asking about animal cells.
Back
Top