Talk:Mechanical advantage

message: I was trying to understand this and was having a difficult time mentally picturing the various pulley systems described. I think some simple illustrations, in the form of diagrams, would be greatly beneficial for readers of this article.  --Wood Thrush 20:25, 23 July 2006 (UTC)
replies: text: A diagram was added --pfctdayelise (talk) 12:41, 2 August 2008 (UTC)
thread_title:  Illustrations 

message: How about mentioning hydraulic and pneumatic systems?  Just as with the lever, it is possible to assemble combinations of pistons and connecting rods that multiply force at the expense of having to move more fluid or gas.  —QuicksilverT @ 21:04, 17 October 2008 (UTC)
replies: text: One guiding principle is, I think, what is common practice in education and industry. It is my experience that in those environments one does not speak in terms of 'mechanical advantage' when discussing hydraulic and pneumatic systems. But of course I may be wrong since I do not know all fields of knowledge. You say: "assemble combinations of pistons and connecting rods that multiply force". In such an assembly the use of 'pistons' seems irrelevant if the emphasis is on the external connections in the light of this article: anything outside the piston is mechanical and is covered in the article. If the increase in force (in other words 'advantage') is principally due to the internals and sizing of parts of the piston can one then still use the term 'mechanical advantage'? That depends on how you break down the working principle of the pistons, etc.. What you are suggesting should be broken down into the elementary parts related to forces and change in forces. Relevant is that the article Hydraulic cylinder alas has no explanation in that area, while it should have. The article Pneumatic cylinder does show a formula, but could do with more explanation. Also pictures are still missing. Articles on Hydraulic motor or Pneumatic motor should also be expanded with information on the force distribution and transfer. The article Fluid power could be expanded a lot to cover these areas. Another one I am thinking of is the use of explosives to create deformation in (large) sheets of metal. Or in airbags. That does not fit in this article (but in a separate article?) but is related to the idea. (I know I am rambling. I hope I make myself clear... It is still early.) --VanBurenen (talk) 09:36, 18 October 2008 (UTC)
thread_title:  Hydraulic and pneumatic systems 

message: A torque multiplier is a specific type of mechanical advantage that is already discussed in this article. As such, it only makes sense for the two article to be merged. Wizard191 (talk) 18:15, 7 May 2009 (UTC)
replies: text: A 'torque multiplier' is a specific type of tool.  It does use mechanical advantage to multiply the torque, however, it being merged with this article does not make sense.  The article for wrench for example, is not and should not be part of the article on Mechanical Advantage, even though a wrench is just a lever used to exert mechanical advantage on something.  A device, and the theory which it operates on, deserve separate articles.  I am removing the redirect for 'torque multiplier' to this article. Tom (talk) 16:54, 27 March 2013 (UTC)
thread_title:  Proposed merge from [[Torque multiplier]] 

message: There is a whole separate approach to using pulleys to obtain mechanical advantage that needs to be addressed here.
See http://www.wesleyan.edu/physics/demos/mechanic/1m2010.html for an illustration of the two approaches.
It is possible to obtain much greater mechanical advantage with only single pulleys using this approach because the overall mechanical advantage is the product of the individual advantages instead of simply the sum. The trade-off is that the pulleys meet after the load has moved only part of the way to the fixed block. This is not always a fatal disadvantage, because the load does not always need to move all the way, and there are common uses of this approach to achieving mechanical advantage. See, for instance the Trucker's hitch. A "Spanish Burton" is typically rigged in the main brace of square rigged sailing ships. This achieves a greater advantage in this critical line with less weight aloft; it allows a sufficient range of motion in the yard. In many cases a combination of approaches are used, so that a final burton is used to multiply the advantage of an additive tackle. A variation that uses slipping points of purchase to get a longer overall range of motion (called a Z hitch, I believe) is taught for some rescue situations. 
--AJim (talk) 02:35, 18 April 2010 (UTC)
replies: text: Jim, I agree with you.  You are free to create a new sub-section and add some explanatory text about the burton configuration.  You can use the Wesleyan.edu website as an in-line citation to support your new sub-section. Dolphin (t) 05:18, 18 April 2010 (UTC)

text: Jim, I believe you're talking about a z-drag.--john.james (talk) 16:16, 18 April 2010 (UTC)

text: Yes, thanks. And there is already an article about it! --AJim (talk) 18:08, 18 April 2010 (UTC)
thread_title:  pulleys used in burton configuration 

message: If it is all right, I would like to make some revisions to this article to clarify the basic principles. Prof McCarthy (talk) 00:45, 5 July 2011 (UTC)
replies: text: Hello Prof McCarthy.  You are most welcome to make revisions to this article, and any other Wikipedia article.  No special approval or permission is required.  Happy editing! Dolphin (t) 01:15, 5 July 2011 (UTC)

text: I have reviewed your draft and made my suggested changes.  I have left some remarks on the Discussion page - see User talk:Prof McCarthy/mechanicaladvantage. Dolphin (t) 03:36, 7 July 2011 (UTC)
thread_title:  Revisions to this article 

message: I have tried to collect some of the articles on machines into the hierarchy of categories Mechanical engineering, Machines, Kinematics, Mechanisms, and Linkages.   Some articles like this one on Mechanical advantage are important enough to appear in a number of broad categories, which causes problems with the hierarchy.  In particular, I think this article should appear in both the introductory physics and mechanical engineering categories, but this forces either introductory physics to be under mechanical engineering or mechanical engineering to be under introductory physics.  I have now done this both ways, and will switch it again if others prefer.  However, I feel it is a small price to pay to ensure this article appears in both categories.  Prof McCarthy (talk) 15:45, 14 October 2011 (UTC)
thread_title:  Categories 

message: Hi I do not know much about the term "mechanical advantage" but clearly two gears interlocked cannot change the force ratio. We need to distinguish between T1/T2 and F1/F2.  — Preceding unsigned comment added by Phvan (talk • contribs) 21:09, 14 February 2012 (UTC)
replies: text: Phvan, thank you for the note but we do not have to distinguish between the force and torque ratios.  These can be calculated as needed.  One of the main uses for machines is to amplify forces and movement.  The slow rotation of the pedals on a bicycle transforms into fast rotation of the rear wheel and therefore speed of the bicycle.  This process changes forces to torque and torque back to forces, so the question of mechanical advantage depends on ratios of forces or torques that are important to the application.  The main point of this article is the connection between the velocity ratio associated with the input and output movement of a machine and its mechanical advantage.  Machines that do not absorb or dissipate power have a velocity ratio that equals the mechanical advantage.  This sets a maximum for the mechanical advantage that can be easily determined from the dimensions and geometry of the machine.  I hope this is helpful. Prof McCarthy (talk) 06:50, 15 February 2012 (UTC)
replies: text:  Following your argument, would you say that the diagram of the lever should reflect a dynamic situation rather than simply two weights in balance? Jimbowley (talk) 11:24, 11 July 2012 (UTC)
thread_title:  Distinguish between torque advantage and force advantage 

message: The current lever diagram needs some forces!  http://en.wikipedia.org/wiki/File:Lever_Principle_3D.png
This is better:  http://es.wikipedia.org/wiki/Archivo:LeverPrincleple.svg at least it has forces but it's not clear what is the input and what the output. 
I would prefer to see a dagram showing a human effort lifting a weight, is that wp:POV though (I have a fetish for machines lifting weights) Jimbowley (talk) 10:52, 11 July 2012 (UTC)
replies: text: Should the diagram depict a stationary or dynamic situation? ie the difference between some work being done, versus a static balance. Does it matter? I don't know. Jimbowley (talk) 11:31, 11 July 2012 (UTC)

text: No-one else have any comment? Ok. I will draw a force lifting a weight with forces Fa,Fb and distances a,b. http://commons.wikimedia.org/wiki/File:Lever_mechanical_advantage.png Jimbowley (talk) 19:21, 27 July 2012 (UTC)
thread_title:  lever diagram 

message: I recommend that leverage (mechanical) redirect here at present.  70.247.162.84 (talk) 16:38, 3 September 2012 (UTC)
thread_title:  Redirect 

message: A recent revision to this article defines mechanical advantage as "how much easier work is."  This is simply not correct.  The best performing machine does not dissipate power, which means the power in equals the power out, so over time the work in and work out are the same.  There is no reduction, or easing, in the amount of power or work.  Furthermore, without any explanation it is impossible to make sense of the equation.
: MA=\frac{LF}{EF}.
Suppose L is load, F is fulcrum and E is effort then LF must represent the distance from the point of application of the load to the fulcrum and EF is similarly the distance from the point of application of the effort to the fulcrum.  However, this same statement is made with the figure and the paragraph that follows.  Prof McCarthy (talk) 20:57, 27 November 2012 (UTC)
replies: text: If it is not correct then it should not be there, right? --VanBurenen (talk) 08:39, 30 November 2012 (UTC)
thread_title:  Law of the lever 

message: In the section "Chain and Belt Drives", under the second equation we have:
:"where NA is the number of teeth on the input sprocket and NB is the number of teeth on the output sprocket.  For a toothed belt drive, the number of teeth on the sprocket can be used.  For friction belt drives the pitch radius of the input and output pulleys must be used."
The language here confused me— particularly I think the sentence starting "For a toothed belt" lays false scent (I came to this article for the first time, browsing). I was just told about the input sprocket and output sprocket: now, which is "the sprocket"? And what sort of mechanism was I reading about before, if now I am to be told about toothed belts?
The third sentence took me a long time to get to after puzzling the second (i. e., because of the false scent), but finally it lights the way out: the second sentence is in apposition to (and apprehension of) this third one on how we measure friction belt drives.
But it is no use to say "the third sentence makes it clear." I stopped at the second, retraced and reread several times in case I had misunderstood something.
Less importantly, there is also a change of grammatical number between sentences from "toothed belt drive" to "friction belt drives", which is not ideal in apposition; "radius" should be "radii"; and "can be" and "must be" are not equivalent.
May I suggest a simplification such as this?:
:"For a chain or toothed belt drive, NA is the number of teeth on the input sprocket and NB is the number of teeth on the output sprocket.
:For a friction belt drive, NA is the radius of the input pulley and NB is the radius of the output pulley.
This wouldn't matter in a more-technical article, but this one is (I presume) aimed at a general audience. I would normally just be WP:BOLD, but I am a little wary that I may have missed something.
Si Trew (talk) 20:43, 11 September 2013 (UTC)
thread_title:  False scent  in "Chain and Belt Drives" section 

message: There seems to be a mistake in the example of the bicycle chain drive (or at least, the wording is strange in my opinion). It states the following:
:Consider the 18-speed bicycle with 7 in (radius) cranks and 26 in (diameter) wheels.  If the sprockets at the crank and at the rear drive wheel are the same size, then the ratio of the output force on the tire to the input force on the pedal can be calculated from the law of the lever to be
:: MA = \frac{F_B}{F_A} = \frac{7}{13} = 0.54
The calculated value of 0.54 here is referring to the crank-wheel ratio and not to the MA value. In fact the MA value of the sprockets is one, since the sprockets are the same size.
I would suggest to replace MA with crank-wheel ratio and remove \frac{F_B}{F_A} from the equation.
Alternatively, change the equation to this:  MA = \frac{F_b}{F_a} = \frac{a}{b} = \frac{7}{13} = 0.54
Sjiep (talk) 10:50, 12 September 2013 (UTC)
replies: text:  This is quite interesting, it is common to calculate gearing for bicycles simple in relation to the gears, while ignoring the crank length or the wheel size, not very correct, but common. This website has information that is relevant but perhaps best put in an area specifically about cycling.
http://sheldonbrown.com/gain.html
Tealeafe (talk) 23:52, 7 December 2013 (UTC)
thread_title:  Slightly confusing terminology in Example: bicycle chain drive 

message: I have proposed to move the disambiguation page Leverage (disambiguation) over the redirect , which currently points to this page. If you would like to participate in the discussion, please see Talk:Leverage (disambiguation)#Requested move 19 March 2015. Ivanvector (talk) 19:17, 19 March 2015 (UTC)
thread_title:  Move request affecting a redirect to this page 

message: An editor has asked for a discussion to address the redirect Gearing. Please participate in the redirect discussion if you have not already done so.  -- 65.94.43.89 (talk) 21:15, 21 March 2015 (UTC)
thread_title:  Gearing listed at [[Wikipedia:Redirects for discussion|Redirects for discussion]] 

message: Substituted at 23:35, 29 April 2016 (UTC)
thread_title: Assessment comment

message: Can't this be simplified by appealing to a balance of torque argument rather than the current argument involving power and velocity? The Torques are balanced when Fa a = Fb b and from that we calculate the mechanical advantage as a/b. --Lbeaumont (talk) 01:15, 4 June 2016 (UTC)
thread_title:  Appeal to "zero sum or torques" rather than the velocity argument