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Dè a th ’anns an sgriubha

Uair: 2020-07-10 Beachd: 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.

Bidh sgriubha cha mhòr an-còmhnaidh air ceann air aon cheann anns a bheil cumadh a chaidh a chruthachadh gu sònraichte a leigeas leis a thionndadh, no a stiùireadh, le inneal. Am measg nan innealan cumanta airson a bhith a ’draibheadh ​​sgriothan tha screwdrivers agus wrenches. Mar as trice tha an ceann nas motha na corp an sgriubha, a chumas an sgriubha bho bhith air a stiùireadh nas doimhne na fad an sgriubha agus gus uachdar giùlain a thoirt seachad. Tha eisgeachdan ann; mar eisimpleir, Boltaichean giùlain 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.


Eadar-dhealachadh eadar bolt agus sgriubha
Bolt carbaid le cnò ceàrnagach
Bolt structarail le cnò hex agus inneal-nigheadaireachd.

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:

Is e inneal-ceangail le snàithlean taobh a-muigh a th ’ann am bolt a chaidh a dhealbhadh airson a chuir a-steach tro thuill ann am pàirtean cruinnichte, agus mar as trice thathas an dùil a theannachadh no a leigeil ma sgaoil le bhith a’ torrachadh cnò. Is e inneal-ceangail le snàithlean taobh a-muigh a th ’ann an sgriubha a dh’ fhaodar a chuir a-steach do thuill ann am pàirtean cruinnichte, a bhith a ’tighinn còmhla le snàithlean preformed a-staigh no a’ cruthachadh a snàithlean fhèin, agus a bhith air an teannachadh no air an leigeil ma sgaoil le bhith a ’torradh a’ chinn. Is e bolt a th ’ann an inneal-ceangail le snàithlean taobh a-muigh a chuireas casg air a thionndadh aig àm cruinneachaidh agus a dh’ fhaodar a theannachadh no a leigeil ma sgaoil le bhith a ’torradh cnò. (Eisimpleir: Boltaichean Ceann Cruinn, Boltaichean slighe, boltaichean treabhaidh.) Is e sgrìob a th ’ann an inneal-ceangail taobh a-muigh le snàithlean a tha a’ toirmeasg co-chruinneachadh le cnò le snàithlean dìreach de dh ’fhaid ioma-phàirce. (Eisimpleir: Sgriothan fiodha, Sgriothan tapadh.) [2]

Tha an dealachadh seo co-chòrdail ri ASME B18.2.1 agus cuid de mhìneachaidhean faclair airson sgriubha [3] [4] agus bolt. [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:
Sgriothan inneal

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.
Sgriothan caip hex

Tha inbhe ASME B18.2.1-1996 a ’sònrachadh Sgriothan Cap Hex a tha eadar meud bho 0.25–3 ann an (6.35–76.20 mm) ann an trast-thomhas. Tha na fasteners seo glè choltach ri Boltaichean hex. 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 Boltaichean 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.
Boltaichean Lug agus boltaichean cinn

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]
Sgriubha Lag
Sgriothan Lag, ris an canar cuideachd boltaichean lag
Sealladh taobh

Tha sgriothan lag (ris an canar cuideachd boltaichean lag, ged is e mì-ainm a tha seo) gu bunaiteach nan sgrìoban mòra fiodha. Tha sgriothan lag le ceann ceàrnagach agus sgriothan lag le ceann hex air an còmhdach le inbhean ASME B18.2.1, agus mar as trice tha an ceann na hex taobh a-muigh. Faodaidh bolt lag àbhaisteach a bhith ann an trast-thomhas bho 1⁄4 ann an (6.35 mm) gu 1 1⁄4 ann an (31.75 mm), agus faid bho 1⁄4 gu 6 ann an (6.35 gu 152.40 mm) no nas fhaide, leis na snàithleanan garbh de chruth snàithlean sgriubha fiodha no duilleag-meatailt-sgriubha (ach nas motha).

Mar as trice tha na stuthan mar substrate stàilinn gualain le còmhdach de galvanization sinc (airson seasamh an aghaidh creimeadh). Faodaidh an còmhdach sinc a bhith soilleir (electroplated), buidhe (electroplated), no galvanized teth-dip liath. Bithear a ’cleachdadh boltaichean lag gus lagachadh a dhèanamh air cumadh fiodha, gus casan innealan a chuir sìos gu làr fiodha, agus airson tagraidhean saorsainneachd trom eile. Thàinig an laga buadhair bho phrìomh chleachdadh tràth de leithid de luchd-ceangail: ceangal lagan mar clàran baraille agus pàirtean eile den aon seòrsa. [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.
Inbhean riaghaltas na SA

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).
Cuspair eachdraidheil

Bha seann inbhean USS agus SAE a ’mìneachadh sgriothan caip mar fasteners le shanks a bha air an snàthadh chun cheann agus boltaichean mar fasteners le shanks a bha ann am pàirt gun leughadh. [19] Tha an dàimh a th ’aig an riaghailt seo ris a’ bheachd gu bheil bolt le mìneachadh a ’toirt cnò soilleir (oir bha dùil gum biodh an earrann gun leughadh den shank, ris an canar an greim, a’ dol tron ​​t-substrate gun a bhith a ’snàith a-steach innte). Tha seo a-nis na eadar-dhealachadh gun fheum.
Briathrachas fo smachd an aghaidh cànan nàdarra

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.

Tha am facal bolt cuideachd na sheann fhacal, agus chaidh a chleachdadh airson linntean airson a bhith a ’toirt iomradh air slatan meatailt a bha a’ dol tron ​​fho-strat gus a cheangal air an taobh eile, gu tric tro dhòighean neo-cheangailte (clinching, tàthadh ceàrdach, pinning, wedging, msaa. ). Tha e follaiseach gu bheil ceangal den chiall seo ri mothachadh bolt dorais no bolt crois-bhogha. Anns an 19mh linn, bhiodh boltaichean ceangailte le snàithleanan sgriubha gu tric air an ainmeachadh boltaichean sgriubha an aghaidh boltaichean clench.

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.
Eadar-dhealachaidhean eile

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.

Is e eadar-dhealachadh a dh ’fhaodadh a bhith ann gu bheil sgriubha air a dhealbhadh gus a snàithlean fhèin a ghearradh; chan eil feum sam bith air faighinn a-steach no taobh eile den taobh eile. Tha am mìneachadh seo air sgriubha air a dhaingneachadh tuilleadh le bhith a ’beachdachadh air leasachaidhean fasteners leithid Tek Screws airson còmhdach mullaich, fèin-drileadh agus sgriothan fèin-tapadh airson diofar thagraidhean ceangail meatailt, sgriothan batten mullaich gus an ceangal eadar batten a’ mhullaich agus an rafter, sgrìoban deic msaa. Air an làimh eile, is e bolt am pàirt fireann de shiostam fastener a chaidh a dhealbhadh gus gabhail ris le socaid (no cnò) ro-uidheamaichte den aon dhealbhadh snàithlean.


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