Search results
Results From The WOW.Com Content Network
In these equations, is the torque applied to screw or nut, is the linear force applied, is the ball screw lead, and is the ball screw efficiency. Selection of the standard to be used is an agreement between the supplier and the user and has some significance in the design of the screw.
Screw theory is the algebraic calculation of pairs of vectors, also known as dual vectors [1] – such as angular and linear velocity, or forces and moments – that arise in the kinematics and dynamics of rigid bodies.
A leadscrew (or lead screw), also known as a power screw [1] or translation screw, [2] is a screw used as a linkage in a machine, to translate turning motion into linear motion. Because of the large area of sliding contact between their male and female members, screw threads have larger frictional energy losses compared to other linkages.
The screw pump is the oldest positive displacement pump. [1] The first records of a water screw, or screw pump, date back to Hellenistic Egypt before the 3rd century BC. [1] [3] The Egyptian screw, used to lift water from the Nile, was composed of tubes wound round a cylinder; as the entire unit rotates, water is lifted within the spiral tube to the higher elevation.
Animation showing the operation of a screw. As the screw shaft rotates, the nut moves linearly along the shaft. This is a type called a lead screw. A machine used in schools to demonstrate the action of a screw, from 1912. It consists of a threaded shaft through a threaded hole in a stationary mount.
A screw axis is associated with each pair of vectors in the algebra of screws, also known as screw theory. [3] The spatial movement of a body can be represented by a continuous set of displacements. Because each of these displacements has a screw axis, the movement has an associated ruled surface known as a screw surface.
The screw thread concept seems to have occurred first to Archimedes, who briefly wrote on spirals as well as designed several simple devices applying the screw principle. Leonardo da Vinci understood the screw principle, and left drawings showing how threads could be cut by machine. In the 1500s, screws appeared in German watches, and were used ...
Many differential screw configurations are possible. The micrometer adjuster pictured uses a nut sleeve with different inner and outer thread pitches to connect a screw on the adjusting rod end with threads inside the main barrel; as the thimble rotates the nut sleeve, the rod and barrel move relative to each other based on the differential between the threads.