Talk:Machine (mechanical)

New article

This article is focusses on the mechanical aspects of machines, which involve primarily forces and movement. This is intended to distinguish machines that are mechanical devices from the use of machine to refer to aspects of computers. Prof McCarthy (talk) 15:12, 12 June 2011 (UTC)[reply]

Mechanism

I am trying to insert the following paragraph. But it does not show up.

A machine consists of an actuator input, a system of mechanisms that generate the output forces and movement, and an interface to the user. Electric motors, hydraulic and pneumatic actuators provide the input forces and movement. Mechanisms consist of gears and gear trains, belt and chain drives, cam and follower mechanisms, linkages and friction devices such as brakes and clutches. Structural components consist of the frame, fasteners, bearings, springs and a variety of specialized machine elements such as splines, pins and keys. The user interface ranges from switches and buttons to programmable logic controllers. Modern machines include computers and sensors that monitor performance and plan movement and are generally called mechanical system. — Preceding unsigned comment added by Prof McCarthy (talk • contribs) 17:32, 12 June 2011 (UTC)[reply]

Mechanical machine

It seems there is a regular need to revise articles about machines so all definitions include computers. This comes from a variety of uses of the term machine in the context of computers, such as machine room, Turing machine, and virtual machine, and perhaps because the original computers used mechanical logic and were strictly limited to mechanical movement. However, for hundreds of years the term computer referred to a person who performed computations. As I have discussed in detail in the talk page on the article "machines" this insistence that our current understanding of a computer correspond with our understanding of a machine makes it difficult to write clearly about the mechanical features of a machine. This discussion of how to distinguish the mechanical features of a machine from everything that others want to have considered to be a machine resulted in the phrase "mechanical machine." The result of that discussion was the creation of this particular article as much to avoid the phrase "mechanical machine" as to allow the focus on the mechanical features of a machine. I hope I can simply request that this phrase not be used in this article. Prof McCarthy (talk) 08:28, 30 March 2012 (UTC)[reply]

a wheel is a machine

What definition of machine are you using when you say a wheel is a machine? Jimbowley (talk) 18:19, 9 July 2012 (UTC)[reply]

I found the American Heritage definition of machines to be helpful. Here is that definition(Prof McCarthy)

Thanks for reply. So, do you think a wheel meets the definition "A device consisting of fixed and moving parts that modifies mechanical energy and transmits it in a more useful form."?

I don't see any mechanical energy coming out in a useful form, only frictional losses. — Preceding unsigned comment added by Jimbowley (talk • contribs) 11:30, 10 July 2012 (UTC)[reply]

A wheel is used to reduce the friction in pulling a cart. It acts to transfer forces in all types of machinery. As I have written in many different places the concept of simple machines is flawed, though our elementary school teachers like it. In my opinion it is not worth the effort to pursue a definition of a simple machine to its logical conclusion. You would be better served by considering the modern formulation introduced by Reuleaux in the late 1800s. Prof McCarthy (talk) 11:29, 11 July 2012 (UTC)[reply]

You are the one stating that a wheel is a machine. But you won't provide a definition of machine that the wheel fits into. Jimbowley (talk) 12:00, 11 July 2012 (UTC)[reply]

Please don't use the strawman argument that I believe in the Renaissance concept of 6 simple machines. Defend your own position not what you imagine is my position. Jimbowley (talk) 12:09, 11 July 2012 (UTC)[reply]

As I have said, I consider this definition, among others, to be useful: "A device consisting of fixed and moving parts that modifies mechanical energy and transmits it in a more useful form." In my opinion it is obvious that a wheel meets this definition. Prof McCarthy (talk) 12:15, 11 July 2012 (UTC)[reply]

Please point me to the more useful form of energy when I'm pulling my cart.Jimbowley (talk) 12:21, 11 July 2012 (UTC)[reply]

Kinetic energy of the cart. Prof McCarthy (talk) 16:22, 11 July 2012 (UTC)[reply]

When pulling a cart along the road at constant speed there is no increase in kinetic energy, all my input energy is going to waste heat. If you want to look at an accelerating cart you will need some extra input force over and above that to overcome friction, as you well know.Jimbowley (talk) 16:58, 11 July 2012 (UTC)[reply]

Perhaps I'm being unfair by not stating my position. So I will. My concept of machine includes useful work output (I'm sure you've gathered that). If that is 'old thinking' and 'new thinking' doesn't use the concept of useful work output, then I will accept that. All I ask is to be shown some evidence that that is indeed the 'new thinking'. As yet no-one has shown me a definition that does not include useful work output/useful form of energy. I think I'm being fair here. Jimbowley (talk) 15:06, 11 July 2012 (UTC)[reply]

You are free to introduce and use any definition of a machine that you like. However, generally the definition of a machine does not include a judgement regarding the usefulness, or benefit, of its operation. Prof McCarthy (talk) 16:25, 11 July 2012 (UTC)[reply]

I'm not trying to do that. But you have yet to show me a single definition that does not include useful work. At least we are getting somewhere, up to now I thought we agreed on the definition, but finally you have stated it does not include useful work. All I need now is to see some evidence of that. Jimbowley (talk) 16:58, 11 July 2012 (UTC)[reply]