There are many simple machines that go into the construction and contribute to the proper functioning of typewriters. Until the rise of computers, typewriters were the most popular machines used for word processing. For most types of typewriters to function properly, each and every type of simple machine is required.
Typewriter as a Compound Machine
A typewriter is considered to be a “compound machine.” What is a compound machine? A compound machine is defined as a device that consists of two or more simple machines. Typewriters are compound machines because they use several types of simple machines to complete the task of printing letters in ink on a given sheet of paper.
Simple Machines in a Typewriter
What is a simple machine? Simple machines are defined as tools that make work easier. Simple machines consist of few, if any, moving parts. They are used to modify or transmit force or motion. The basic types of simple machines include the lever, inclined plane, wheel and axle, screw, wedge and pulley.
Explanation of Simple Machines
Levers are some of the most basic types of simple machines. A lever is simply a bar or a board that sits on a fulcrum (a turning point). An inclined plane is a flat surface, one end is higher than the other on an inclined plane. The wheel and axle simple machine consists of a rod, or axle, which goes through a wheel. A screw is merely an inclined plane which twists around itself. A wedge is made up of two inclined planes that meet to form a sharp edge. Pulleys are another type of simple machine, a pulley consists of a wheel and a rope or cable.
Function of Simple Machines in a Typewriter
Each different type of simple machine used in a typewriter has its practical application. The keys on a typewriter are attached to levers. When a specific key is punched, it activates a lever which pushes the key against an ink ribbon that hugs a sheet of paper, leaving the key's impression in ink on the paper. Ink ribbons that stretch between two spools acts as a pulley as well as a wheel and axle. The paper in a typewriter acts as a wedge which shifts upward between a typewriter's platen and paper bail. The paper feed in a typewriter functions as an inclined plane. The worm gear is a screw that turns the platen after the carriage turn lever has been engaged.
Electrical Typewriters and Simple Machines
Not every type of typewriter that has ever been created requires the use of all simple machines to properly function. Electrical typewriters for example, although they are still considered to be compound machines, do not require several of the simple machines that older, manually operated models require.
Sources:
Classic Typewriter Page: A Brief History of Typewriters site.xavier.edu Accessed Aug 2010
Virtual Typewriter Museum: Why Typewriters? typewritermuseum Accessed Aug 2010
University of Houston: Simple Machines Learning Site. atlantis.coe.uh Accessed Aug 2010
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