WordNet

a simple machine consisting of a wheel with a groove in which a rope can run to change the direction or point of application of a force applied to the rope (同)pulley-block, pulley block, block
a pulley on a shaft that presses against a guide belt to guide or tighten it (同)idler pulley, idle wheel
take away; "pull the old soup cans from the supermarket shelf"
strain abnormally; "I pulled a muscle in my leg when I jumped up"; "The athlete pulled a tendon in the competition" (同)overstretch
the force used in pulling; "the pull of the moon"; "the pull of the current"
special advantage or influence; "the chairmans nephew has a lot of pull" (同)clout
the act of pulling; applying force to move something toward or with you; "the pull up the hill had him breathing harder"; "his strenuous pulling strained his back" (同)pulling
a device used for pulling something; "he grabbed the pull and opened the drawer"
a sustained effort; "it was a long pull but we made it"
cause to move in a certain direction by exerting a force upon, either physically or in an abstract sense; "A declining dollar pulled down the export figures for the last quarter" (同)draw
cause to move by pulling; "draw a wagon"; "pull a sled" (同)draw, force
take sides with; align oneself with; show strong sympathy for; "We all rooted for the home team"; "Im pulling for the underdog"; "Are you siding with the defender of the title?" (同)root for
apply force so as to cause motion towards the source of the motion; "Pull the rope"; "Pull the handle towards you"; "pull the string gently"; "pull the trigger of the gun"; "pull your knees towards your chin"
hit in the direction that the player is facing when carrying through the swing; "pull the ball"
move into a certain direction; "the car pulls to the right"
operate when rowing a boat; "pull the oars"
rein in to keep from winning a race; "pull a horse"
steer into a certain direction; "pull ones horse to a stand"; "Pull the car over"

PrepTutorEJDIC

滑車;滑車装置;ベルト車
《しばしば副詞[句]を伴って》〈物〉‘を'『引く』,『引っ張る』,引いて動かす / 〈人・人の体の一部・衣服など〉‘を'『ぐいと引っ張る』,強く引く / …‘を'引き抜く,引き離す,取りはずす / 《副詞[句]を伴って》〈布など〉‘を'引き裂く,引きちぎる / 〈筋肉など〉‘を'引っ張って痛める,引きつらせる / 《話》〈観客・支持者など〉‘を'引きつける,集める / 《話》(…に向かって)〈ナイフ・ピストルなど〉を引き抜く《+『名』+『on』+『名』》 / 《米話》〈悪事・策略・冒険など〉‘を'やってのける / 『引っ張る』,引く / 『引っ張られる』,引ける / 引きずるように動く / こぐ,こいで進む / 〈C〉『引くこと』,一引き / 〈C〉《単数形で》(人の)引く力:〈U〉(自然の)引力 / 〈C〉《単数形で》必死に引っ張る(引きずる)こと / 〈C〉《複合語を作って》物を引っ張る道具;引き手,取っ手,引き綱 / 〈C〉(液体の)一飲み,(たばこの)一服《+『at』+『名』》 / 〈U〉《時にa pull》《話》引き,手づる,コネ / 〈U〉《米話》人を引きつける力 / 〈C〉(野球・ゴルフで)球を引っ張って打つこと

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/09/03 06:08:09」(JST)

wiki en

A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a cable or belt along its circumference.^[1] Pulleys are used in a variety of ways to lift loads, apply forces, and to transmit power. In nautical contexts, the assembly of wheel, axle, and supporting shell is referred to as a "block."

A pulley may also be called a sheave or drum and may have a groove between two flanges around its circumference. The drive element of a pulley system can be a rope, cable, belt, or chain that runs over the pulley inside the groove.

Hero of Alexandria identified the pulley as one of six simple machines used to lift weights.^[2] Pulleys are assembled to form a block and tackle in order to provide mechanical advantage to apply large forces. Pulleys are also assembled as part of belt and chain drives in order to transmit power from one rotating shaft to another.^[3]^[4]

Block and tackle

Various ways of rigging a tackle.^[5]

A set of pulleys assembled so that they rotate independently on the same axle form a block. Two blocks with a rope attached to one of the blocks and threaded through the two sets of pulleys form a block and tackle.^[6]^[7]

A block and tackle is assembled so one block is attached to fixed mounting point and the other is attached to the moving load. The ideal mechanical advantage of the block and tackle is equal to the number of parts of the rope that support the moving block.

In the diagram on the right the ideal mechanical advantage of each of the block and tackle assemblies^[5] shown is as follows:

Gun Tackle: 2
Luff Tackle: 3
Double Tackle: 4
Gyn Tackle: 5
Threefold purchase: 6

Rope and pulley systems

Pulley in oil derrick

A hoist using the compound pulley system yielding an advantage of 4. The single fixed pulley is installed on the hoist (device). The two movable pulleys (joined together) are attached to the hook. One end of the rope is attached to the crane frame, another to the winch.

A rope and pulley system -- that is, a block and tackle -- is characterised by the use of a single continuous rope to transmit a tension force around one or more pulleys to lift or move a load—the rope may be a light line or a strong cable. This system is included in the list of simple machines identified by Renaissance scientists.^[8]^[9]

If the rope and pulley system does not dissipate or store energy, then its mechanical advantage is the number of parts of the rope that act on the load. This can be shown as follows.

Consider the set of pulleys that form the moving block and the parts of the rope that support this block. If there are p of these parts of the rope supporting the load W, then a force balance on the moving block shows that the tension in each of the parts of the rope must be W/p. This means the input force on the rope is T=W/p. Thus, the block and tackle reduces the input force by the factor p.

A gun tackle has a single pulley in both the fixed and moving blocks with two rope parts supporting the load W.
Separation of the pulleys in the gun tackle show the force balance that results in a rope tension of W/2.

A double tackle has two pulleys in both the fixed and moving blocks with four rope parts supporting the load W.
Separation of the pulleys in the double tackle show the force balance that results in a rope tension of W/4.

How it works

The simplest theory of operation for a pulley system assumes that the pulleys and lines are weightless, and that there is no energy loss due to friction. It is also assumed that the lines do not stretch.

In equilibrium, the forces on the moving block must sum to zero. In addition the tension in the rope must be the same for each of its parts. This means that the two parts of the rope supporting the moving block must each support half the load.

Fixed pulley
Diagram 1: The load F on the moving pulley is balanced by the tension in two parts of the rope supporting the pulley.
Movable pulley
Diagram 2: A movable pulley lifting the load W is supported by two rope parts with tension W/2.

These are different types of pulley systems:

Fixed: A fixed pulley has an axle mounted in bearings attached to a supporting structure. A fixed pulley changes the direction of the force on a rope or belt that moves along its circumference. Mechanical advantage is gained by combining a fixed pulley with a movable pulley or another fixed pulley of a different diameter.
Movable: A movable pulley has an axle in a movable block. A single movable pulley is supported by two parts of the same rope and has a mechanical advantage of two.
Compound: A combination of fixed and a movable pulleys forms a block and tackle. A block and tackle can have several pulleys mounted on the fixed and moving axles, further increasing the mechanical advantage.

Diagram 3: The gun tackle "rove to advantage" has the rope attached to the moving pulley. The tension in the rope is W/3 yielding an advantage of three.
Diagram 3a: The Luff tackle adds a fixed pulley "rove to disadvantage." The tension in the rope remains W/3 yielding an advantage of three.

The mechanical advantage of the gun tackle can be increased by interchanging the fixed and moving blocks so the rope is attached to the moving block and the rope is pulled in the direction of the lifted load. In this case the block and tackle is said to be "rove to advantage."^[10] Diagram 3 shows that now three rope parts support the load W which means the tension in the rope is W/3. Thus, the mechanical advantage is three.

By adding a pulley to the fixed block of a gun tackle the direction of the pulling force is reversed though the mechanical advantage remains the same, Diagram 3a. This is an example of the Luff tackle.

Free body diagrams

The mechanical advantage of a pulley system can be analyzed using free body diagrams which balance the tension force in the rope with the force of gravity on the load. In an ideal system, the massless and frictionless pulleys do not dissipate energy and allow for a change of direction of a rope that does not stretch or wear. In this case, a force balance on a free body that includes the load, W, and n supporting sections of a rope with tension T, yields:

The ratio of the load to the input tension force is the mechanical advantage MA of the pulley system,^[11]

Thus, the mechanical advantage of the system is equal to the number of sections of rope supporting the load.

Belt and pulley systems

Flat belt on a belt pulley

Belt and pulley system

Cone pulley driven from above by a line shaft

A belt and pulley system is characterised by two or more pulleys in common to a belt. This allows for mechanical power, torque, and speed to be transmitted across axles. If the pulleys are of differing diameters, a mechanical advantage is realised.

A belt drive is analogous to that of a chain drive, however a belt sheave may be smooth (devoid of discrete interlocking members as would be found on a chain sprocket, spur gear, or timing belt) so that the mechanical advantage is approximately given by the ratio of the pitch diameter of the sheaves only, not fixed exactly by the ratio of teeth as with gears and sprockets.

In the case of a drum-style pulley, without a groove or flanges, the pulley often is slightly convex to keep the flat belt centred. It is sometimes referred to as a crowned pulley. Though once widely used on factory line shafts, this type of pulley is still found driving the rotating brush in upright vacuum cleaners, in belt sanders and bandsaws. ^[12] Agricultural tractors built up to the early 1950s generally had a belt pulley for a flat belt (which is what Belt Pulley magazine was named after). It has been replaced by other mechanisms with more flexibility in methods of use, such as power take-off and hydraulics.

Just as the diameters of gears (and, correspondingly, their number of teeth) determine a gear ratio and thus the speed increases or reductions and the mechanical advantage that they can deliver, the diameters of pulleys determine those same factors. Cone pulleys and step pulleys (which operate on the same principle, although the names tend to be applied to flat belt versions and V belt versions, respectively) are a way to provide multiple drive ratios in a belt-and-pulley system that can be shifted as needed, just as a transmission provides this function with a gear train that can be shifted. V belt step pulleys are the most common way that drill presses deliver a range of spindle speeds.

References

^ Oxford English Dictionary. Oxford University Press. 1989. A wheel with a groove round its rim, a sheave. A wheel or drum fixed on a shaft and turned by a belt, cable, etc.,
^ Usher, Abbott Payson (1988). A History of Mechanical Inventions. USA: Courier Dover Publications. p. 98. ISBN 0-486-25593-X.
^ Uicker, John; Pennock, Gordon; Shigley, Joseph (2010). Theory of Machines and Mechanisms (4th ed.). Oxford University Press, USA. ISBN 978-0-19-537123-9.
^ Paul, Burton (1979). Kinematics and dynamics of planar machinery (illustrated ed.). Prentice-Hall. ISBN 978-0-13-516062-6. CS1 maint: Extra text (link)
^ ^a ^b MacDonald, Joseph A. Handbook of Rigging: For Construction and Industrial Operations. McGraw-Hill Professional. p. 376. ISBN 978-0-07-149301-7.
^ Prater, Edward L. (1994). "Basic Machines" (PDF). Naval Education and Training Professional Development and Technology Center, NAVEDTRA 14037.
^ Bureau of Naval Personnel (1971). "Basic Machines They Work" (PDF). Dover Publications.
^ Avery, Elroy (2003). Elementary physics. Sheldon and company.
^ Bowser, Edward (1890). An elementary treatise on analytic mechanics: With numerous examples (5 ed.). D. Van Nostrand company. p. 180.
^ "Seamanship Reference, Chapter 5, General Rigging" (PDF). sccheadquarters.com.
^ Tiner, J. H. Exploring the World of Physics: From Simple Machines to Nuclear Energy. Master Books (May 1, 2006) p. 68.
^ http://woodgears.ca/bandsaw/crowned_pulleys.html

External links

http://www.khanacademy.org/science/physics/mechanics/v/mechanical-advantage--part-3

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 手指の解剖学 finger and thumb anatomy
2. ばね指（狭窄性屈筋腱腱鞘炎） trigger finger stenosing flexor tenosynovitis
3. 遠位指節間関節の屈筋腱の損傷（ジャージー指） flexor tendon injury of the distal interphalangeal joint jersey finger
4. 眼振の概要 overview of nystagmus
5. History and examination of the adult with hand pain

English Journal

The mid-South clinical data research network.

Rosenbloom ST1, Harris P2, Pulley J3, Basford M4, Grant J5, DuBuisson A6, Rothman RL7.
Journal of the American Medical Informatics Association : JAMIA.J Am Med Inform Assoc.2014 Jul;21(4):627-32. doi: 10.1136/amiajnl-2014-002745. Epub 2014 May 12.
The Mid-South Clinical Data Research Network (CDRN) encompasses three large health systems: (1) Vanderbilt Health System (VU) with electronic medical records for over 2 million patients, (2) the Vanderbilt Healthcare Affiliated Network (VHAN) which currently includes over 40 hospitals, hundreds of a
PMID 24821742

Percutaneous trigger thumb release in children: neither effective nor safe.

Masquijo JJ1, Ferreyra A, Lanfranchi L, Torres-Gomez A, Allende V.
Journal of pediatric orthopedics.J Pediatr Orthop.2014 Jul-Aug;34(5):534-6. doi: 10.1097/BPO.0000000000000119.
BACKGROUND: Although percutaneous trigger thumb release has been extensively used in adults, the technique is not widespread in children. The purpose of this study was to evaluate the efficacy and safety of percutaneous trigger thumb release in the pediatric age group.METHODS: Twenty consecutive thu
PMID 24322630

CORR® ORS Richard A. Brand Award for Outstanding Orthopaedic Research: Engineering Flexor Tendon Repair With Lubricant, Cells, and Cytokines in a Canine Model.

Zhao C1, Ozasa Y, Reisdorf RL, Thoreson AR, Jay GD, An KN, Amadio PC.
Clinical orthopaedics and related research.Clin Orthop Relat Res.2014 Jun 7. [Epub ahead of print]
BACKGROUND: Adhesions and poor healing are complications of flexor tendon repair.QUESTIONS/PURPOSES: The purpose of this study was to investigate a tissue engineering approach to improve functional outcomes after flexor tendon repair in a canine model.METHODS: Flexor digitorum profundus tendons were
PMID 24906811

Operative technique for human composite flexor tendon allograft procurement and engraftment.

DeGeorge BR Jr1, Rodeheaver GT, Drake DB.
Annals of plastic surgery.Ann Plast Surg.2014 Jun;72 Suppl 2:S191-7. doi: 10.1097/SAP.0000000000000091.
Devastating volar hand injuries with significant damage to the pulley structures and fibro-osseous sheath, flexor tendons, and volar plates pose a major problem to the reconstructive hand surgeon. Despite advances in tendon handling, operative technique, and postoperative hand rehabilitation, patien
PMID 24691346

Japanese Journal

パワートレイン部会ベルト・プーリ分科会の活動状況報告

竹内和夫
自動車技術 65(11), 106-107, 2011-11-01
NAID 10029796359

屈筋腱縫合後の腱・腱鞘間滑走抵抗: In a canine model in vivo

佐藤正義,西田淳,赤坂俊樹,川村竜平,鈴木忠,嶋村正
岩手医学雑誌 63(4), 219-228, 2011-10-01
NAID 110008665535

明らかな外傷既往のない長母指屈筋腱皮下断裂の1例

今村悠哉,入江弘基,堀川朝広,石井一誠,瀬形建喜,米村憲輔,水田博志
整形外科と災害外科 60(4), 612-616, 2011-09-25
NAID 10029660534

Related Pictures

Dorman® 300-201 - Power Steering Pump Pulley Garage Door Pulley | Ideal Security Inc 4.5L TRD Keyed Pulley M90 Quick Pulley Kit (3.5psi & 3.0psi Pulleys) - ModdBox HTD 3M 72T Timing Pulley 16mm Belt Width Gear Belt Pulley 72Teeth 8/10/12/14/15/16/17 Dorman® 300-318 - Power Steering Pump Pulley TB WOOD'S 5/8 TB WOOD'S 3/4

★リンクテーブル★

「pull」

Pulley
	Pulleys on a ship. In this context, pulleys are usually known as blocks.
Classification	Simple machine
Industry	Construction, transportation
Wheels	1
Axles	1

　　[★]

引く

関: draw、subtract

[1] Oxford English Dictionary. Oxford University Press. 1989. A wheel with a groove round its rim, a sheave. A wheel or drum fixed on a shaft and turned by a belt, cable, etc.,

[Usher-2] Usher, Abbott Payson (1988). A History of Mechanical Inventions. USA: Courier Dover Publications. p. 98. ISBN 0-486-25593-X.

[3] Uicker, John; Pennock, Gordon; Shigley, Joseph (2010). Theory of Machines and Mechanisms (4th ed.). Oxford University Press, USA. ISBN 978-0-19-537123-9.

[4] Paul, Burton (1979). Kinematics and dynamics of planar machinery (illustrated ed.). Prentice-Hall. ISBN 978-0-13-516062-6. CS1 maint: Extra text (link)

[advantage-5] MacDonald, Joseph A. Handbook of Rigging: For Construction and Industrial Operations. McGraw-Hill Professional. p. 376. ISBN 978-0-07-149301-7.

[6] Prater, Edward L. (1994). "Basic Machines" (PDF). Naval Education and Training Professional Development and Technology Center, NAVEDTRA 14037.

[7] Bureau of Naval Personnel (1971). "Basic Machines They Work" (PDF). Dover Publications.

[8] Avery, Elroy (2003). Elementary physics. Sheldon and company.

[Bowser-9] Bowser, Edward (1890). An elementary treatise on analytic mechanics: With numerous examples (5 ed.). D. Van Nostrand company. p. 180.

[10] "Seamanship Reference, Chapter 5, General Rigging" (PDF). sccheadquarters.com.

[Tiner-11] Tiner, J. H. Exploring the World of Physics: From Simple Machines to Nuclear Energy. Master Books (May 1, 2006) p. 68.

[12] ttp://woodgears.ca/bandsaw/crowned_pulleys.html

匿名

検索

案内

案内

pulley