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Waktos: 2020-07-10 mairan: 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 saklar ampir bakal gaduh sirah dina hiji tungtung anu ngandung bentuk anu khusus kabentuk anu ngamungkinkeun pikeun dihurungkeun, atanapi didorong, nganggo alat. Alat anu umum pikeun nyetir screws kalebet skru sareng rengking. Sirah biasana langkung ageung tibatan awak screw, anu ngajaga skru teu janten didorong langkung jero tibatan panjang skru sareng nyayogikeun permukaan. Aya éntitas; contona, Baut gerbong 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.


Perbezaan antara baud sareng screw
Baut gerbong sareng nut alun-alun
A baut struktural kalayan nut hex sareng washer.

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:

Bolt nyaéta pamancing anu sacara luar benang éksternal anu dirancang pikeun sisipan ngalangkungan liang dina patempatan anu dipasang, sareng biasana dimaksudkeun ku dikencangkeun atanapi dikaluarkeun ku nyéép nut. Sakrup kénging mangrupikeun pengikat benang éksternal anu tiasa dilebetkeun kana liang dina patempatan anu dipasang, ku kawin nganggo benang internal anu preformed atanapi ngabentuk benang nyalira, sareng dinaheut atanapi dikaluarkeun ku sikina sirah. Penggantian anu aya benang sacara éksternal anu dicegah teu dirungkabkeun nalika dipasang sareng anu tiasa dikedalkeun atanapi dikaluarkeun ngan ukur ku nyéépkeun nut. (Conto: Bolong Kepala Buleud, Lacak Bolts, bajak bolts.) Hiji pengancing anu aya benang éksternal anu ngagaduhan bentuk benang anu nyaram perhimpunan ku pin anu ngagaduhan benang lempeng tina panjang pitch nyaéta skru. (Conto: Sekrup Kayu, Ngetok Topeng.) [2]

Béda ieu konsisten sareng ASME B18.2.1 sareng sababaraha definisi kamus pikeun skru [3] [4] sareng baut. [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:
Mesin Mesin

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 cap cap

ASME standar B18.2.1-1996 netepkeun Hex Cap Screws anu ukuranana tina 0.25–3 dina (6.35-76.20 mm) diaméterna. Pecat ieu ampir sami Hex Bolts. 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 Hex baud".[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.
Lugar bolts sareng sirah baut

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]
Lag screw
Boleng, disebut ogé baut lag
Hiji tempoan samping

Boleng-anteng (disebut ogé lag bolts, sanaos ieu anu misnomer) dina hurung tatarisan ageung. Kepala sérbut alun-alun sareng skru lag hex-head katutup ku standar ASME B18.2.1, sareng sirah biasana hex éksternal. Bolt lag khas tiasa dibasajankeun diaméter tina 1⁄4 dina (6.35 mm) ka 1 1⁄4 dina (31.75 mm), sareng panjangna tina 1⁄4 dugi ka 6 (6.35 dugi ka 152.40 mm) atanapi langkung panjang, nganggo benang kasar. tina skru kayu atanapi lambar-logam-skég (tapi langkung ageung).

Bahan-bahanna biasana substrat baja karbon sareng lapisan palapis séng (kanggo tahan korosi). Palapis séng tiasa terang (electroplated), koneng (electroplated), atanapi abu-abu kusam panas dipeléduksi. Lag bolts dianggo pikeun ngahiji gantung kayu, nepi ka mesin mesin lag kana lanté kai, sareng kanggo aplikasi tukang kayu. Kecap sipat lag asalna tina panggunaan poko sapertos péstol sapertos: pengantosan lags sapertos tong tong sareng bagian anu sami. [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.
Standar pamaréntahan AS

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).
Masalah sajarah

Standar USS kuno sareng SAE leres ditetepkeun screws cap salaku pamanén sareng garan anu dipasang ka sirah sareng bolts salaku pangikat kalayan garan anu teu sawaréh dibaca. [19] Hubungan aturan ieu pikeun ideu yén baut ku definisi nyokot nut jelas (sabab bagian tina shank anu teu acan dibahas, anu disebut cengkraman, diperkirakeun ngalangkungan substrat tanpa nyolok). Ieu bédana bénten.
Kosa kata anu dikontrol ngalawan basa alami

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.

Kecap bolt ogé mangrupikeun kecap anu lami pisan, tur éta dianggo salami abad kajul kana batang logam anu ngalangkungan substrat diarahkeun sanés, sering ku hartos nonthreaded (clinching, forge welding, pinning, wedging, jsb. ). Sambungan arti ieu kana akal tina hiji baut panto atanapi baut silang anu jelas. Dina abad ka-19, bolts diikat ku benang skru sering disebat bolongan sela anu saling bertentangan sareng baut 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.
Bédana sanés

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.

Bedana kamungkinan nyaéta skru anu dirancang pikeun motong threadna sorangan; éta henteu peryogi aksés ti atanapi paparan kanggo sabalikna tina komponén anu diikat. Definisi skru ieu ogé dikuatkeun ku pertimbangan pamekaran pengikat sapertos Tek Screws pikeun cladding atap, pangeboran diri sareng nyaring-nyentak pikeun rupa-rupa aplikasi pengikat logam, bumbung batten pikeun nguatkeun hubungan antara batten batten sareng usuk usul, ngawut-awut sareng anu sanésna, sisi sanés, sungsu nyaéta bagian jalu dina sistem pélén anu dirancang pikeun katampa ku stop kontak pre-dilengkepan (atanapi nut) tina desain anu leres.


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