Helical structure used to convert between rotational and linear movement or force
Screw thread, used to convert torque into the linear force in the flood gate. The operator rotates the small vertical bevel gear in the center. Through mechanical advantage this causes the horizontal bevel gears (at far left and far right, with threaded center holes) to rotate. Their rotation raises or lowers the two long vertical threaded shafts - as they are not free to rotate.
A screw thread is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called a straight thread and the latter called a tapered thread. A screw thread is the essential feature of the screw as a simple machine and also as a threaded fastener.
The mechanical advantage of a screw thread depends on its lead, which is the linear distance the screw travels in one revolution.[1] In most applications, the lead of a screw thread is chosen so that friction is sufficient to prevent linear motion being converted to rotary, that is so the screw does not slip even when linear force is applied, as long as no external rotational force is present. This characteristic is essential to the vast majority of its uses. The tightening of a fastener's screw thread is comparable to driving a wedge into a gap until it sticks fast through friction and slight elastic deformation.
^Burnham, Reuben Wesley (1915). Mathematics for Machinists. John Wiley & sons, Incorporated. p. 137. Retrieved 4 April 2018 – via Internet Archive.
A screwthread is a helical structure used to convert between rotational and linear movement or force. A screwthread is a ridge wrapped around a cylinder...
The ISO metric screwthread is the most commonly used type of general-purpose screwthread worldwide. They were one of the first international standards...
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Unified Thread Standard (UTS) defines a standard thread form and series—along with allowances, tolerances, and designations—for screwthreads commonly...
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generally used three thread sizes. The Unified Thread Standard (UTS) originates from the United States, while the ISO metric screwthread is standardized worldwide...
A screwthread, often shortened to thread, is a helical structure used to convert between rotational and linear movement or force. A screwthread is an...
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[citation needed] A screw jack consists of a heavy-duty vertical screw with a load table mounted on its top, which screws into a threaded hole in a stationary...
measure Screwthread, a helical ridge on a cylindrical fastener Thread, an individual strand of spider silk Thread (film), 2016 Greek film Threads (1932...
standards for screwthreads that has been adopted internationally for interconnecting and sealing pipes and fittings by mating an external (male) thread with an...
general purpose metric screwthread—tolerances) is an International Organization for Standardization (ISO) standard for metric screwthread tolerances. It specifies...
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