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Thei screw e

Time: 2020-07-10 Agahkişî: 41

A screw, or bolt, is a type of fastener, typically made of metal, and characterized by a helical ridge, known as a male thread (external thread) or just thread, wrapped around a cylinder. Some screw threads are designed to mate with a complementary thread, known as a female thread (internal thread), often in the form of a nut or an object that has the internal thread formed into it. Other screw threads are designed to cut a helical groove in a softer material as the screw is inserted. The most common uses of  Screws  are to hold objects together and to position objects.

A screw dê hema hema her tim serê li ser yek dawiya ku tê de pêkenokek ku bi rengek taybetî hatî damezrandin heye ku dihêle ku ew alavek vegere, an rêve bibe. Amûrên hevbeş ên ji bo zencîreyên ajotinê rêgezên dorpêçkirin û wergiran in. Serê bi gelemperî ji laşê screwê mezintir e, ku qurmê ji ajotinê pirtir kûrtir dibe û dirêjiyê lêdide çêdibe û astek rakêşiyê peyda dike. Îstîsna hene; bo nimûne, Kulîlkên gerîdokê have a domed head that is not designed to be driven; set screws often have a head smaller than the outer diameter of the screw; J- Bolts  have a J-shaped head which is not designed to be driven, but rather is usually sunk into concrete allowing it to be used as an anchor bolt. The cylindrical portion of the screw from the underside of the head to the tip is known as the shank; it may be fully threaded or partially threaded.[1] The distance between each thread is called the "pitch".

The majority of screws are tightened by clockwise rotation, which is termed a right-hand thread; a common mnemonic device for remembering this when working with screws or bolts is "righty-tighty, lefty-loosey." Screws with left-hand threads are used in exceptional cases. For example, when the screw will be subject to counterclockwise torque (which would work to undo a right-hand thread), a left-hand-threaded screw would be an appropriate choice. The left side pedal of a bicycle has a left-hand thread.

More generally, screw may mean any helical device, such as a clamp, a micrometer, a ship's propeller or an Archimedes' screw water pump.


Cûdahiyê di navbera bol û screw
Kulîlkek gerîdok bi nivîşkek zevî
Boltek strûktir bi hewa hêcaz û şûjinê.

There is no universally accepted distinction between a screw and a bolt. A simple distinction that is often true, although not always, is that a bolt passes through a substrate and takes a nut on the other side, whereas a screw takes no nut because it threads directly into the substrate. Machinery's Handbook describes the distinction as follows:

Pirek pêvek bi kincê xerîbî ye ku ji bo vexwarinên di parçeyên têne civandin de tête çêkirin, û bi gelemperî armanc e ku meriv bi tîrêjê zexm ve were xurtkirin an jî were berdan. A screw is a fastener threaded derveyî ku bikaribe têkevê nav perçên berhevkirî, ji hevberdana bi mijara navxweyî ya pêşdetir an çêkirina mijara xwe, û ji hêla hişk an serêş ve were teng kirin an tê berdan. Zencîreke zencîre ya derveyî ya ku di dema civînê de tête asteng kirin û ku bi zor an zalimê ve were qefilandin an jî serbest kirin dikare pişkek e. (Mînak: Boltên Serê Round, Bolts bişopînin, zendikên çilmisîn.) Zencîrekî zencîre ya bi derveyî ku xwediyê formê mijê ye ku civat bi nivînek qedexe dike xwediyê niqteyek rasterast a dirêjahiya pirjimariyê ye. (Mînak: Pelên dar, Nakokiyên Tap kirin.) [2]

Ev cudahî bi ASME B18.2.1 û hin bêjeyên ferhengê ji bo screw [3] [4] û boltê pêkve ye. [5] [6] [7]

The issue of what is a screw and what is a bolt is not completely resolved with Machinery's Handbook distinction, however, because of confounding terms, the ambiguous nature of some parts of the distinction, and usage variations.[8][not in citation given] Some of these issues are discussed below:
Screwên makîneyê

ASME standards specify a variety of "Machine Screws"[9] in diameters ranging up to 0.75 in (19.05 mm). These fasteners are often used with   Nuts  as well as driven into tapped holes. They might be considered a screw or a bolt based on the Machinery's Handbook distinction. In practice, they tend to be mostly available in smaller sizes and the smaller sizes are referred to as screws or less ambiguously as machine screws, although some kinds of machine screw can be referred to as stove bolts.
Hex kilamên hespan

ASME standard B18.2.1-1996 screws Hex Cap diyar dike ku di navbera 0.25-3-ê de (6.35-76.20 mm) bi diameter. Van fasteners pir dişibin hev Hex Bolt. They differ mostly in that they are manufactured to tighter tolerances than the corresponding bolts. Machinery's Handbook refers parenthetically to these fasteners as "Finished Hezikên hex".[10] Reasonably, these fasteners might be referred to as bolts, but based on the US government document Distinguishing Bolts from Screws, the US government might classify them as screws because of the tighter tolerance.[11] In 1991 responding to an influx of counterfeit fasteners Congress passed PL 101-592[12] "Fastener Quality Act" This resulted in the rewriting of specifications by the ASME B18 committee. B18.2.1[13] was re-written and as a result they eliminated the "Finished Hex Bolts" and renamed them the "Hex Cap Screw"-a term that had existed in common usage long before, but was now also being codified as an official name for the ASME B18 standard.
Kulîlkên serê zirav û serê zirav

These terms refer to fasteners that are designed to be threaded into a tapped hole that is in part of the assembly and so based on the Machinery's Handbook distinction they would be screws. Here common terms are at variance with Machinery's Handbook distinction.[14][15]
Dûrika darê
Zûngirên lagê, di heman demê de qulikên lag jî têne gotin
Nêrînek alî

Pirtûka paşîn (her weha ev têgînek xeletker jî tê gotin) bi bingehîn qurmikên darên mezin in. Zencîreyên dorpêçê yên çarçik û serê hexikên hex-serî bi standardên ASME B18.2.1 ve têne dorpêç kirin, û serê bi gelemperî hebek heksek derveyî ye. Dûreyek lêdana tîpîk dikare di navbera 1⁄4-ê de (6.35 mm) û 1 1 in4-ê di (31.75 mm) de, û dirêjiyên ji 1⁄4-ê di 6-ê de (6.35 ji 152.40 mm) an jî dirêjtir be, bi dirûvên kûr. of a screw-screw or sheet-metal-screw-screw (lê mezintir).

Materyal bi gelemperî substrate ya karbonê ye ku bi hevzayek ji galvanîzasyona zinc (ji bo berxwedana korozyonê). Kincê zincî dibe ku bi rengek zelal (xalîçêkirî), zer (elektrîk), an galgalek germî ya darê zirav bibe. Boltên lagê têne bikar anîn ku bihevra dirûşm bikin, lingên makîneyê bisekinin berbi daristanan, û ji bo serlêdanên din ên kargêriya giran. Têlên paşnav ji karanîna bingehîn a zûtir a van pêvekan dihatin: fastening of lags wek stûnên bermîl û parçeyên din ên mînahev. [16]

These fasteners are "screws" according to the Machinery's Handbook criteria, and the obsolescent term "lag bolt" has been replaced by "lag screw" in the Handbook.[17] However, in the minds of many tradesmen, they are "bolts", simply because they are large, with hex or square heads. In the United Kingdom and Australia, lag screws are known as coach screws.
Pîvanên Hikûmeta Amerîkî

The US government made an effort to formalize the difference between a bolt and a screw because different tariffs apply to each.[18] The document seems to have no significant effect on common usage and does not eliminate the ambiguous nature of the distinction between screws and bolts for some threaded fasteners. The document also reflects (although it probably did not originate) significant confusion of terminology usage that differs between the legal/statutory/regulatory community and the fastener industry. The legal/statutory/regulatory wording uses the terms "coarse" and "fine" to refer to the tightness of the tolerance range, referring basically to "high-quality" or "low-quality", but this is a poor choice of terms, because those terms in the fastener industry have a different meaning (referring to the steepness of the helix's lead).
Mijara dîrokî

Standardên USS û SAE ya kevnar wek qefilên ku bi serê serî ve hatine girêdan û qulpikên wekî pişkên ku bi parçebûn nehatine qewirandin qefilên kapê wekî qulpikên kapan destnîşan kirin. [19] Têkiliya vê qaîdeyê bi ramana ku çuçek ji hêla tewandî ve mirîşkê digire zelal e (ji ber ku beşa bêhempa ya şeklê, ya ku jê re tê gotin grip, tê xwestin ku di binê jehrê re bê derbas kirin. Ev naha cihêrengiyek nuvaze.
Dengbêjên kontrolkirî li dijî zimanê xwezayî

The distinctions above are enforced in the controlled vocabulary of standards organizations. Nevertheless, there are sometimes differences between the controlled vocabulary and the natural language use of the words by machinists, auto mechanics and  Others . These differences reflect linguistic evolution shaped by the changing of technology over centuries. The words bolt and screw have both existed since before today's modern mix of fastener types existed, and the natural usage of those words has evolved retronymously in response to the technological change. (That is, the use of words as names for objects changes as the objects themselves change.) Non-threaded fasteners predominated until the advent of practical, inexpensive screw-cutting in the early 19th century. The basic meaning of the word screw has long involved the idea of a helical screw thread, but the Archimedes screw and the screw gimlet (like a corkscrew) preceded the fastener.

Gotina bolt di heman demê de peyveke pir kevn e û bi sedsalan hate bikar anîn da ku meriv rindiyên metalî yên ku di binê bendavê re derbas dibin da ku li aliyek din werin çandin, gelemperî bi navgînên ne-pijiyayî (klînîkirin, felckirina weldê, pendkirin, zewq û hwd. ). Girêdana vê hişê bi têleka deriyê zirav an qulikê xaçerêyê diyar e. Di sedsala 19-an de, pêlên ku bi pêlavên zencîreyê hatine girêdan, gelek caran bi nakokî digerin ku qulikên zirav nebin.

In common usage, the distinction (not rigorous) is often that screws are smaller than bolts, and that screws are generally tapered while bolts are not. For example, cylinder head bolts are called "bolts" (at least in North American usage) despite the fact that by some definitions they ought to be called "screws". Their size and their similarity to a bolt that would take a nut seem linguistically to overrule any other factors in this natural word choice proclivity.
Cûdahiyên din

Bolts have been defined as headed fasteners having external threads that meet an exacting, uniform bolt thread specification (such as ISO metric screw thread M, MJ, Unified Thread Standard UN, UNR, and UNJ) such that they can accept a non-tapered nut. Screws are then defined as headed, externally threaded fasteners that do not meet the above definition of bolts.[citation needed] These definitions of screw and bolt eliminate the ambiguity of the Machinery's handbook distinction. And it is for that reason, perhaps, that some people favor them. However, they are neither compliant with common usage of the two words nor are they compliant with formal specifications.

Cûdahiyek mumkun e ku darika xêzik were çêkirin ku dirûna xwe qut bike; Pêdivî tune ku meriv ji alîyê berevajî yê jûreya ku pê re hatî pêçan kirin an têxe dorhêlê. Ev pênase ya screw ji hêla nêrîna pêşkeftinên pêvekên mîna Tek Screws ve ji bo lêdana çargoşe, screws self-drilling û xwe-çikandin ji bo sepanên cihêrengkirinê yên cuda yên metal, qefilandinên zexîreyên çîmentoyê ji bo xurtkirina pêwendiya di navbera banî deştê û rafter, screws dekking hwd. Ji aliyekî din ve, pişk perçeyek nêr a sîstema fastener e ku tête pejirandin ji hêla pêvekek pêşîn (an nivîn) ve bi heman rengî ya sêwiranê.


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