SIMPLE MACHINES and/or CLEVER TOOLS

[ricardo]

Ok what about a divining rod? It's a tool and a machine. The simple part is the rod itself; but since the user is a person that is complicated, therefore a machine, and arguably an indispensable aspect of the act of divining, the whole apparatus rod + user = tool/machine?

Or are metaphysical apparati not allowed?  ;D

One of the great power amplifier designers, Arthur Bailey of Radford & Bradford University was a water diviner.  He did the classic Radford STA15/25/50s (eg http://www.r-type.org/articles/art-097.htm) and also the early transistor amps. including the first commercial transistor amps with fully complementary output stages.  Also the Transmission Line speaker in the form we know it today.

On one famous occasion he found someone's burst water main over the telephone by asking him to get a long phone extension lead.

Dr. Bailey is no longer with us but he certainly didn't regard water divining any more metaphysical than designing amps.  I regret never asking him for an explanation when I lived in Bradford.

 

[bruce0]

A Knob

Now I know what it controls is not a simple machine, but the knob is an astounding example of a simple machine, with tactile and visual feedback both accepting and communicating information (pointer).

If you question this, just try to use one of those little audio recorders with the buttons to adjust gain etc.  I never buy any audio thing that does not have a knob on it.

 

[JohnRoberts]

A Knob

Now I know what it controls is not a simple machine, but the knob is an astounding example of a simple machine, with tactile and visual feedback both accepting and communicating information (pointer).

If you question this, just try to use one of those little audio recorders with the buttons to adjust gain etc.  I never buy any audio thing that does not have a knob on it.

Simple knob diameter creates a mechanical advantage over trying to turn the small pot shaft alone. Some vernier knobs with locking mechanism are more than simple machines with gear ratios, etc. Rather than add mechanical advantage the gear reduction is for added resolution.

JR

 

[bruce0]

Venier knobs aside.

A knob tells you what the value is by looking at the pointer
A knob allows you to adjust the value by turning it
A knob lets you feel the value change by how much you twist your thumb and forefinger (opposable thumb required)
A knob communicates the range of values and where you are in the range.
And yes, a knob is a lever, but so much more.  A knob is a user interface of the best kind.  A metaphor for machine control understood universally from time immemorial.  Perhaps the antecedent of the lever, but a huge improvement.

Compare to little buttons... press once to increase value press more times or longer to increase value more, no idea what the value is (usually there is a little screen, sometimes the first click is ignored to turn on the light on the screen, sometimes not based upon engineers whim). 

A knob is an amazing machine.

But I am also fond of the inclined plane, and the fishing pole for skiing and dinner.

And for that matter - clubs, rocks, wheels, and fire!  Which my brother once opined were the basis of all machines.

Along the border between tool and machine

Bruce

 

[PRR]

> A knob is a user interface of the best kind.  A metaphor for machine control understood universally from time immemorial.

"time immemorial"? I can't think of a flow-control knob a lot over 100 years ago. Gas stoves.

Before that we adjusted dams and wood/coal burners with levers on gates/shutters.

I first thought you meant "door-knobs". That's probably not a lot over 200 years old.

 

[bruce0]

Ok... Ok... Sorry...Perhaps not time immemorial (although I don't remember it).


But valves with rotational components date to roman times.  As I was perusing Valve Magazine (just kidding)...
http://www.valvemagazine.com/index.php/web-only/categories/manufacturing/4947-ancient-roman-valves

So those valves are from Pompeii - Which Pliny the Elder (the old windbag) dates with his death to sometime before August of 79 A.C.E. I believe.  So figure at least 2000 years old we have used valves with rotational components.

I suspect they go earlier.  Egypt and Ancient china (2000 BCE) but I haven't found any pictures of those to show that they had a knob that turned.

Anyway... Sorry.... I should have said "for a very long time".

You guys are tough taskmasters!

Doorknobs don't really cover it.  They are knobs or levers but they are binary (latched or not latched) and so not really as wonderful as a knob.

 

[genghiscohen]

http://www.pdnotebook.com/wp-content/themes/thesis_16/custom/images/Five_hundred_and_seven_mechanical_moveme.pdf
perhaps not all so simple.

What about the ratchet?

http://www.youtube.com/watch?v=mpkTHyfr0pM
or a mechanical computer. Simple is relative.

 

[JohnRoberts]

Yup, ratchet does not apply any mechanical advantage, but it is time and labor saving. Kind of like a mechanical diode that only transfers rotational force in only one direction.

JR

 

[walter]

String or rope. Rope for the pulley, or more complex, chain. What about for a Bolo sling? And of course knots. and fabric. A piece of fabric used to harness wind energy...

 

[JohnRoberts]

String or rope.

Rope wrapped around an axel lets you translate linear force into rotational force. The diameter of axel (pulley) provides mechanical advantage like leverage.

Rope for the pulley,

Multiple pulleys like in a block and tackle provide mechanical advantage. Or backwards like in my weight machine that uses steel cable and pulleys, two pulleys in place of one increase the effective weight of the weight stack. 

or more complex, chain.

Sprockets, are like gear ratios with leverage.

What about for a Bolo sling?

You mean the thrown weapon for tripping animals? I guess it creates an advantage for hunters but not exactly mechanical.

And of course knots.

??  [edit] upon reflection there is more going on in knots than simple friction so mechanical advantage from different arrangements. [/edit]

and fabric. A piece of fabric used to harness wind energy...

I guess the sail is a simple machine  of sorts.

Then there's the wing, and propellor, and

This thread is going all over the place, but that is cool...

Thanx.

JR

 

[walter]

I did a search for "mechanics of a knot" and there is a lot of information on the web. Knot theory and statistical mechanics, who knew string could be so interesting... Buckets were made in the pacific northwest by weaving tree bark... Harnessing wind for sailing vessels, and harnessing wind for milling.

 

[JohnRoberts]

I often lean toward the "gordian" knot solution.

JR

 

[JohnRoberts]

Sorry to bump this old thread and I think knife edge has been mentioned in passing, but I sharpened my lawnmower blade this weekend and the difference is remarkable.

The previous blunt knife edge was several times thicker before i sharpened it, this literally doubles the cutting force for every halving of knife edge thickness.

Happiness is a sharp blade...

JR

 

[PRR]

I finally sharpened my chainsaw. This is usually forced on me by hitting dirt. This time I felled and bucked over a dozen good dead pines, with a used chain, and it slowly got slow and bindy.

I haven't tried it yet, dodging thunder and sprinkles.

 

[JohnRoberts]

Happiness is a sharp blade...  ;D  I have a chain saw sharpening file too...

I have a stand of pines that need to come down, but they are too tall and near a power line.. I need to get somebody to top them.

They survived Katrina because pine trees are wimpy, they drop their limbs rather than falling over, while they do not have good roots so can be blown over. I worry when mine finally do come down they'll take prisoners.

JR

 

[sr1200]

pliers - its a lever of sorts that converts force on one end thru the fulcrum to the other.  always amazes me that a tiny pair of pliers allows me to get those hex nuts off way eaiser than my hand can.  Always wondered if its more the application of force or more the grip on the tiny (or large) piece that really matters.

 

[PRR]

Chain is better. I think I need a new file.

Pines can have good roots. However in my wet acre there is a thermocline. Much of the muck is 38 degree F 11 months a year. There's a steady ooze of sub-surface water from the uphill land. You can't heat water from the top. 38 deg F water is as dense as it gets; warmer or colder rises away. Normal pine and cedar has the "tap root" going straight down. Here I can pull root-lumps out with a small boat-winch, and the tap-root makes a 90 degree bend at the thermocline and grows sideways.

Despite the bad rooting, they love to grow so close that one can't fall without snagging another.

Last winter I had a jack-straw of 6 or 8 blow-down pines and cedars all tangled together and blocking access to my drain ditch. I also had a quite healthy but poorly rooted pine snag at a 40 degree angle right close to my power line.

 

[JohnRoberts]

Applied science is much more rewarding than theory.

This weekend I was reminded about the benefits of a sharp blade on an unexpected simple tool. I am nearing the end of a major earth redistribution project in my yard, moving dirt from where I have too much to where I do not have enough. The specific problem this weekend was digging up some established grass turf. My shovel was proving too hard to push into the ground to cut through the dense grass roots..

Ah ha... the shovel needed to be sharpened. Sure enough the cutting edge of the shovel was peened over from decades of hitting rocks and other hard things, so 5 minutes with my file put a fresh edge on my shovel and it was then cutting through the grass roots like butter.

The difference between the new sharp edge and old flattened edge was a factor of several times less force needed.  ;D

JR

 

[AMZ-FX]

P-38 can opener (larger than life size in the photo):

-Jack

 

[JohnRoberts]

Yup I remember p-38s from C-RATs back when I was in the green machine.

1- lever for mechanical advantage
2- knife edge for mechanical advantage
3- hinge for compact storage

JR