Machines mechanical advantage

Simple machine Compound machine Mechanical advantage... 

In brief, the mechanical advantage of a lever or any machine equals the ratio of the distance the applied force moves to the distance the load moves. 

The term mechanical advantage is used to described how effectively a simple machine works. Mechanical ad-... 

Sometimes the mechanical advantage of a machine is less than one. That is, a person has to put in more force than the machine can move. Class three levers are examples of such machines. A person exerts more force on a class three lever than the lever can move. The purpose of a class three lever, therefore, is not to magnify the amount of force that can be moved, but to magnify the distance the force is being moved. 

The mechanical advantage of a wheel and axle machine can be found by dividing the radius of the wheel by the radius of the axle. For example, suppose that the crank on a water well turns through a radius of 2 ft (61 cm) and the radius of the axle around which the rope is wrapped is 4 in (10 cm). Then the mechanical advantage of this wheel and axle system is 2 ft divided by 4 in, or 6. 

Mechanical advantage— A mathematical measure of the amount by which a machine magnifies the force put into the machine. 

Compound machines are two or more simple machines working together. A wheelbarrow is an example of a complex machine. It uses a lever and a wheel and axle. Machines of all types ease workload by changing the size or direction of an applied force. The amount of effort saved when using simple or complex machines is called mechanical advantage or MA. 

Hand tools are designed and built based on the properties of simple machines (see Chapter 10). Hand tools use the mechanical advantages of simple machines to help us perform various tasks. Before performing some of these tasks, a technician uses measuring tools to layout the prototype. 

Mechanical advantage is gaining increased force or motion by using a machine. 

Compound and simple machines use a concept termed mechanical advantage. Mechanical advantage refers to gaining increased force or extended motion hy means of a machine. We typically describe mechanical advantage mathematically. Mechanical advantage is the ratio of force that performs the work to the force initially applied to the machine. 

FIGURE 10-5 The lever is a very useful simple machine. It provides a mechanical advantage to help with work. 

Simple machine n. A contrivance for the transfer of energy and for increased convenience in the performance of work. Mechanical advantage is the ratio of the resistance overcome to the force applied. Velocity ratio is the ratio of the distance through which force is applied to the distance through which resistance is overcome. Efficiency is the ratio of the work done by a machine to the work done upon it. If a force / applied to a machine through a distance S results in a force F exerted by the machine through a distance 5, neglecting friction... 

Actually, the force obtained from the machine will have a smaller value than will satisfy the equation above. If P be the actual force obtained, the practical mechanical advantage will be... 

If large quantities of simple parts are to be produced, a mechanical winding machine offers advantages. Programming consists of coordinating the motion... 

Mechanical advantage (MA) is the ratio between resistance overcome and effort applied. When determining the mechanical advantage of a system, the resistance is divided by the effort. For example, when a 100-lb force moves a resistance force of 400 lb, the machine has a mechanical advantage of 4. Actual MA is calculated using the following equation ... 

Since pressing force generaUy ranges from some 10s of grams to kilograms per lead, the mechanical advantage of a reproducible press machine is required for press-fit connector apphcation. 

Under mechanical and environmental stresses, composites are dimensionally stable. They maintain their shape and functionaHty, a critical requirement in such appHcations as dish antennas, constmction girders, and in appHance and business machines. Color and surface texture can often be molded into an FRP product for long lasting, low maintenance permanent surface appearance. Boats are a good example. The surface color is molded in and requires minimum maintenance, an advantage in saltwater environments. 

Soft starting minimizes the starting mechanical and thermal stresses/shocks on the machine and the motor. It results in reduced maintenance cost, fewer breakdowns and hence longer operating life for both. Reduced starting current is an added advantage. 

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