# What simple machine is a cam/eccentric?

• PenguinCo
Therefore, a cam/eccentric can be classified as a circular wedge, as it falls under the category of a revolute joint. In summary, machines should be classified based on their function rather than their geometry, as modern mechanics has proven the limitations of the traditional simple machine categories. Reuleaux's approach of focusing on joints and connections is a more comprehensive and accurate way of understanding machines.

#### PenguinCo

Now I know that levers, wheels, screws, inclined planes, wedges, and pulleys (which I believe are actually levers in disguise), are the classical simple machines from way back when. Although I can classify things into these categories, I'm having trouble determining which of them a cam/eccentric fall into. They could be wheels, or they could be inclined planes...? If anybody hase some insight, clearing this up for me would really help!

Thanks,
PenguinCo.

Why does it matter?
Some machines are comprised of combinations of simple machines - it is pointless to try to put everything into a simplistic taxonomy.

Note: a pulley may be used to obtain mechanical advantage - in which case it is a special case of a lever: a round lever. However, it can also be used as a pulley to change the direction of action of the tension in a cord. You can also use a rod and pivot to do this. When so used, the rod is a special case of a pulley.
In other words, a machine is properly classified by its function, not it's geometry. At least in terms of physics or engineering.

A cam/eccentric is just a circular wedge.

From Wikipedia:
Although they continue to be of great importance in mechanics and applied science, modern mechanics has moved beyond the view of the simple machines as the ultimate building blocks of which all machines are composed, which arose in the Renaissance as a neoclassical amplification of ancient Greek texts on technology. The great variety and sophistication of modern machine linkages, which arose during the Industrial Revolution, is inadequately described by these six simple categories. As a result, various post-Renaissance authors have compiled expanded lists of "simple machines", often using terms like basic machines,[8] compound machines,[5] or machine elements to distinguish them from the classical simple machines above. By the late 1800s, Franz Reuleaux[10] had identified hundreds of machine elements, calling them simple machines.

[...]

Classification of machines

[...]

However, a more successful strategy was identified by Franz Reuleaux, who collected and studied over 800 elementary machines. He realized that a lever, pulley, and wheel and axle are in essence the same device: a body rotating about a hinge. Similarly, an inclined plane, wedge, and screw are a block sliding on a flat surface.[28]

This realization shows that it is the joints, or the connections that provide movement, that are the primary elements of a machine. Starting with four types of joints, the revolute joint, sliding joint, cam joint and gear joint, and related connections such as cables and belts, it is possible to understand a machine as an assembly of solid parts that connect these joints.

## 1. What is a cam/eccentric?

A cam/eccentric is a simple machine that is used to convert rotary motion into reciprocating motion, or vice versa. It consists of a circular or oval-shaped disc that is off-center from its axis, causing a wobbling or sliding motion when rotated.

## 2. How does a cam/eccentric work?

A cam/eccentric works by using the off-center rotation of the disc to push or pull on a connected object, causing it to move in a back-and-forth or up-and-down motion. The shape of the cam/eccentric determines the type and direction of the motion.

## 3. What are some examples of a cam/eccentric?

Some examples of a cam/eccentric include the camshaft in a car engine, which helps open and close the engine's valves, and the crankshaft in a bicycle, which converts circular pedaling motion into linear motion to turn the wheels.

## 4. What are the advantages of using a cam/eccentric?

One advantage of using a cam/eccentric is that it can convert motion in different directions and speeds, making it useful for a variety of tasks. It is also relatively simple and easy to design and can be used to create complex movements.

## 5. What are the limitations of a cam/eccentric?

One limitation of a cam/eccentric is that it can only produce reciprocating or oscillating motion, and not continuous rotation. It also requires precise design and alignment to function properly, which can be challenging to achieve in some cases.