As a ratchet, you can use an ascender, mechanical rope grasp, or a friction knot connected with a prusik loop. We can create the correct tool for the job by constructing systems out of various combinations of mechanical advantage pulleys, change of direction pulleys, rope, anchors, and ratchets.
A mechanical advantage (MA) is the ratio between output force and input force. Mechanical advantage allows us to reduce the force required to move something heavy or lift something high. A machine with large mechanical advantage can be operated by a person who weighs much less than the machine. A person using a winch operates on a small scale model of a MA machine. A motorized vehicle such as a tractor uses another type of MA machine called a gearbox to increase its speed and power while keeping its weight low.
The simplest form of mechanical advantage is a lever. With a lever, the force applied to one end of the device applies a greater force at the other end. This is because the other end is being pulled back by that same force. You can see this in action when someone uses a crane to lift something heavy: they are applying force to the controls, which causes the crane's hook to rise up high enough for them to take it down again. The person doing the lifting only has to provide the force necessary to raise the crane's hook. A crane with large mechanical advantage can be lifted by someone who is not even aware that it is there.
Ratchets are devices that constrain rotational or linear motion to one direction exclusively. This design may be utilized to develop a mechanism that allows the limited motion's direction to be adjusted. Ratchet mechanisms are often used in tools, such as hand-powered screwdrivers, to allow the user to turn the tool in either direction but not reverse it.
The name "ratchet" comes from the French word meaning "little wheel", which refers to the eye of the pawl or other gear used to lock the ratchet mechanism in place.
Ratchet mechanisms can be divided into two main types: external and internal. In an external ratchet, the user turns a handle or another form of actuator to move a pawl between positions where it engages and releases a pin or detent on the ratchet body. On the internal type, a pawl moves within a housing to engage the ratchet body's teeth or not, depending on the direction of movement.
External ratchets tend to be cheaper and easier to make than internal ones, but they can't provide as much locking power as their more expensive counterparts. Internal ratchets can be stronger but also heavier and more complicated to manufacture.
Ratchet mechanisms were originally developed for use with machinery powered by humans or animals.
A ratchet is a handle that is connected to one end of a socket by a square-drive connection. The opposite end of the socket is designed to fit over a fastener. A mechanism in the ratchet allows the handle to engage and tighten the fastener when swung clockwise and freely when swung counterclockwise. There are two types of ratchets: open and closed. Open ratchets can be used with any type of fastener, while closed ratchets are only used with nuts and bolts.
Closed ratchets have two parts: a body and a cover. The cover is placed on top of the body and fits tightly to allow free movement of the handle but prevent access to the inside parts of the ratchet. This prevents objects from being pulled into the body or exposed when removed for storage or transport. The cover can be opened up when needed for replacement of cotter pins, washers, or locknuts.
Open ratchets do not have a cover. Instead, they use a square drive connection between the body and the handle to connect them together. This allows open ratchets to be used with most any type of fastener, but it also makes them more vulnerable to damage since there is no protective cover over the driving mechanism. Open ratchets usually contain additional internal parts that are required to be lubricated to function properly. These parts include springs and washers that act as bearings and sockets that hold the handles in place while allowing rotation.