This MedLibrary.org supplementary page on Wheel and axle is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
The wheel and axle is a simple machine.
The traditional form as recognised in 19th century textbooks is as shown in the image. This also shows the most widely recognised application, ie lifting water from a well. The form consists of a wheel that turns an axle and in turn a rope converts the rotational motion to linear motion for the purpose of lifting.
By considering the machine as a torque multiplier, ie the output is a torque, items such as gears and screwdrivers can fall within this category.
Contents |
Calculating mechanical advantage
Ideal mechanical advantage
The ideal mechanical advantage of a wheel and axle is calculated with the following formula:
The effort distance is the radius, diameter, or circumference of whichever part of the simple machine, wheel or axle, is initially being rotated. The resistance distance is the same measurement of the opposite part of the wheel and axle. For example, if the axle is initially rotated and the wheel is rotated by the axle then the axle is the effort distance and the wheel would be the resistance distance.
The oldest wheel was found in Mesopotamia and is believed to be over 5,500 years old.
Actual mechanical advantage
The actual mechanical advantage of a wheel and axle is calculated with the following formula:
where
- R = resistance force, i.e. the weight of the bucket in this example.
- Eactual = actual effort force, the force required to turn the wheel.
Examples
- Doorknobs are similar to the water well, as the mechanism uses the axle as a pinion to withdraw the latch.
- With a simple chain fall, the user pulls on the wheel using the input chain, so the input motion is actually linear.
- Screwdrivers - an example of the rotational form. The diameter of the handle gives a mechanical advantage.
- Gears
See also
|
|||||
Wikipedia content modification information:
- This page was last modified on 2 December 2008, at 07:15.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Wheel and axle".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.