A compound machine is one that is made up of two simple machines: a wheel and axle and a wedge. All pencil sharpeners are composed of these two parts.
The wheel is the part that rotates and the axle is the part that moves back and forth. On most sharpeners, the wheel is attached to the handle at one end and to the blade holder at the other. When you roll the handle forward, the wheel spins and the blade holder moves backward, raising the point of the pencil sharpener. When you pull the handle back, the blade holder moves forward, lowering the point of the pencil sharpener.
This is how all standard pencil sharpeners work. Some add a third element, called an arbor, which allows the wheel to spin even when not being rolled along by the handle. This is useful if you want to use the sharpener with thick sticks of wood or coal. Otherwise, the wheel will stop when the handle is pulled back after each stroke.
For ordinary writing paper, the point is usually sharp enough that you only need to push the handle forward slightly to lift it off the paper.
What exactly is a compound machine? This is a machine that combines two simpler machines. A nice example is a mechanical pencil sharpener. The handle (wheel and axle) is turned, and the two cutting screws sharpen the pencil. There are three main types of compounds: rolling-element, sliding-piece, and helical.
Why are some machines called "compounds"? This comes from the fact that the parts work together to produce a combined effect. The name "compound machine" is used for machines with multiple parts who work together to produce a result. For example, a washing machine has a motor, pulleys, a belt, and a fan all working together to power the washer drum.
Some engineers like to say that anything that can be built by humans can be built by machines. While this is not true in general, it does apply to certain kinds of machines. For example, a human can build a robot arm made out of many separate pieces (joints) that connect rods together.
There are also automatic machines that function without any help from people. An example is an automated car factory. These are not as popular as compound or multi-component machines, but they do exist.
Simple machines are classified into six types: a lever, a wedge, an inclined plane, a screw, a pulley, and a wheel and axle. This is known as the "mechanical advantage" of the machine. Pencil sharpeners employ either a wedge alone or a wedge combined with a wheel and axle. This type of machine is called a "sharpening machine."
A wedge is any piece of wood, metal, or other material that, when used as a fulcrum for applying pressure to another object, allows it to be lifted or lowered without requiring further application of force. Wedges can be used alone or in combination with other elements to create more complex mechanisms such as axes. A common example of this is the axe head, which includes one end of a wedge shaped blade attached to a handle.
Lever systems include two or more levers connected by rigid members (arms) that allow the mechanism to operate over a wide range of positions. Lever systems are often used in machinery since they require little effort on the part of the operator to move a large block or weight along with them. The word "lever" comes from the French word "levier," which means "to lift."
Inclined planes consist of a sloping surface against which objects can be placed to be slid down the slope. There are two types of inclined planes: straight and curved.
Simple machines are used to facilitate work. They are employed at various points and stages throughout our life. The pulley, screw, wheel and axle, wedge, lever, and inclined plane are among them. Compound machines are created by combining two or more basic machines. For example, a motor is a simple machine that converts electrical energy into mechanical power, so it can be used as the driving force for a complex machine such as a pump or fan.
Screws are commonly used in machinery for their ability to transmit torque and turn objects such as nuts and bolts. A screw is a rigid rod with a sharp point on one end and a flat surface called an helix formed around its outer circumference. It can be straight or curved, but it must have a continuous thread of uniform depth down its entire length. Screws come in many sizes and types. Each type is designed for particular applications where weight, cost, or space limitations make it advantageous to use a single screw instead of several smaller ones. For example, wood screws are usually less expensive than stainless steel screws but they won't last as long because they can't withstand high temperatures like their metal counterparts can.
A screwdriver is a tool for turning screws. It has a thin, pointed tip and a handle attached to a shaft, which is inserted into the head of the screw you want to remove or drive.
Here are some common examples of basic machines.
Simple machines include levers, pulleys, and wedges. A wire cutter pliers is made up of a first-class lever's fulcrum. It is employed in the cutting of cables. As a result, wire cutter pliers are a complex mechanism. They consist of two parts: a handle portion and a cable gripping portion. The handle is shaped like a "T" with its narrow end toward the base. On the inside wall of this end is a curved piece called the lifter. The fulcrum for the first-class lever is located between the lifter and the base of the tool. When pressure is applied to the top of the tool, it cuts through the cable.
In addition to wire cutter pliers, there are other tools that can be considered as simple machines: sledgehammer, mallet, and axes. These tools are all composed of a heavy head connected to a stick or pole by a straight arm.
Thus, a machine is any device that uses wheels or gears to produce power or do work. Modern machines can be extremely complicated involving many parts that perform several tasks using different methods.
A compound machine is two or more basic machines combined to do work. Compound machines, as opposed to simple machines, have moving components. A pair of scissors, for example, are two levers that move past one other to perform work. The advantage of a compound machine is that the movement of each part can be adjusted independently of the others. This allows the designer to optimize performance characteristics such as strength to weight ratio, ease of construction, or cost.
Simple machines consist of a single lever or arm connected to a driving wheel or pulley at one end and to an output device at the other. They are very efficient but can do only one type of work using one degree of freedom (the angle between the axis of the shaft and the plane of the base). For example, a crane is a simple machine used by engineers to lift heavy objects. It consists of a boom with a hook on it; a gantry beneath the object to be lifted; and a cable connecting the hook to the gantry. When you pull the rope attached to the hook, it lifts the object up into the air. Crane operators use this fact by lifting objects that are too large to lift with one person directly above them on the gantry.
Compound machines can do more types of work than simple machines. For example, a rocker-boom truck combines two simple machines: a rocker and a boom.