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The simple mechanical elements that comprise complex machines, like robots, are described.

Complex machines are made up of moving parts such as levers, gears, cams, cranks, springs, belts, andwheels. Machines deliver a certain type of movement to a desired location from an input force applied somewhere else. Somemachines simply convert one type of motion to another type, such as rotary to linear. While there is a seemingly endless varietyof machines, they are all based upon simple machine elements. The elements discussed here include inclined planes, levers, wheels and axles,pulleys, and screws.

It is important to remember that all machines are limited in their efficiency by friction. No machine is 100 percent efficientin its efforts, so the mechanical advantage gained will require additional energy to accomplish the task. For more information on friction, see this module

The inclined plane

An inclined plane decreases the force required to raise an object a given height byincreasing the distance over which that force must be applied, see . Imagine lifting something twice your weight to a 4 foot high shelf. Now imagine rolling the same mass up a gentlysloping surface. The latter would be much easier. Inclined planes are commonly put to use in cutting devices and oftentwo inclined planes are put back to back to form a wedge. In a wedge, forward movement is converted into a parting movementacting perpendicular to the face of the blade. A zipper is simply a combination of two lower wedges for closing and an upper wedge for opening, as shown in .

Inclined Plane
The Inclined Plane at Work

The screw

The Screw

The screw is basically an inclined plane (see ) wrapped around a cylinder. In an inclined plane, a linear force in thehorizontal plane is converted to a vertical "lifting" force. With a screw, a rotary force in the horizontal plane isconverted to a vertical "lifting" force.

When a wood screw is turned, the threads of the screw push up on the wood. A reaction force from the woodpushes back down on the screw threads and in this way the screw moves down even though the force of turning the screw isin the horizontal plane. Screws are known for high friction, which is why they are used to hold things together. A worm gear is sometimes used in machines, but they also have high friction that can waste considerable power.


A lever has three points of interest: the fulcrum, the load, and the effort applied to the lever. The fulcrum is the point around which the lever pivots rotationally. The load is what we wish to manipulate with the lever, and the load is described by its position relative to the fulcrum, and the force (magnitude and direction) it exerts at that point.The effort is also a force that has a magnitude and a direction, and a position with respect to the fulcrum. A leveris used to change the direction of movement, and to trade the magnitude of the effort for the distance over whichthe effort is applied.

Classes of Levers

Questions & Answers

what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, An introduction to mechanical engineering for high school students. OpenStax CNX. Feb 08, 2009 Download for free at http://cnx.org/content/col10640/1.1
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