Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Block And Tackle shopping experience:
1. Compare - without doubt the biggest advantage that the Block And Tackle offers shoppers today is the ability to compare thousands of Block And Tackle at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.
2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about
3. Testimonials - don't know anybody that has bought a Block And Tackle? Wrong! If the Block And Tackle is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.
4. Questions - Got a question about Block And Tackle then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....
5. Reputation - Never heard of the company selling Block And Tackle? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Block And Tackle and build up a picture of their reputation for sales, returns, customer service, delivery etc.
6. Returns - still worried that even after all of the above your Block And Tackle wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.
7. Feedback - happy with your Block And Tackle then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.
8. Security - check for the yellow padlock on the Block And Tackle site before you buy, and the s after http:/ /i.e. https:// = a secure site
9. Contact - got a question about Block And Tackle, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.
10. Payment - ready to pay for your Block And Tackle, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.
of the
Mercator (ship) is used to help lower a boat.
A
block and tackle"Tackle" can be pronounced International Phonetic Alphabet: in this usage. is a system of two or more pulleys with a
rope or cable threaded between them, usually used to lift or pull heavy loads.
Overview
Although used in many situations, they are especially common on boats and sailing ships, where motorized aids are usually not available, and the task must be performed manually. The block and tackle pulley was invented by
Archimedes.
Mechanical advantage
The most common arrangement is to have a set of fixed pulleys or "sheaves" all mounted on a single axle, and another set left to move. Each set is called a "block" (the whole assembly, with the rope, is the "tackle"). The mechanical advantage of a block and tackle is equal to the number of lines running between the two blocks. For example, a tackle consisting of three fixed and three moving pulleys has six lines going between the pulleys, which gives it a mechanical advantage of 6. This enables the lifting of weights six times heavier than would be possible otherwise.
Friction
The increased force produced by a tackle is offset by both the increased length of rope needed and the friction in the system. In order to raise a block and tackle with a mechanical advantage of 6 a distance of 1
metre, it is necessary to pull 6 metres of rope through the blocks. Frictional losses also mean there is a practical point at which the benefit of adding a further sheave is offset by the incremental increase in friction which would require additional force to be applied in order to lift the load. Too much friction may result in the tackle not allowing the load to be released easilyFriction may mean that the rope in a tackle "bunches" and jams when the force is released if the tackle has too much friction for the load to balance, or that the tackle does not "lower" the load, or by the reduction in force needed to move the load being judged insufficient because undue friction has to be overcome as well.
Friction may sometimes be useful, for example in absorbing the recoil of a
gun laying#Muzzle Loading Artillery.
Rigging methods
A tackle may be
- "Rigged to advantage" - where the pull on the rope is in the same direction as that in which the load is to be moved
- "Rigged to disadvantage" - where the pull on the rope is in the opposite direction to that in which the load is to be moved
While it may seem logical to rig to advantage in every case, the decision of which to use depends on pragmatic considerations for the total
ergonomics of working with a particular situation.
See also
Notes
References
- Rescue Technician: Operational Readiness for Rescue Providers, edited by Claire Merrick et al., published by Mosby, Inc., St. Louis, Mo., 1998, copyright held by Maryland Fire and Rescue Institute. ISBN 0-8151-8390-9 See Chapters 4 and 5, p. 41 and ff.
External links
of the
Mercator (ship) is used to help lower a boat.
A
block and tackle"Tackle" can be pronounced International Phonetic Alphabet: in this usage. is a system of two or more
pulleys with a
rope or
cable threaded between them, usually used to lift or pull heavy loads.
Overview
Although used in many situations, they are especially common on
boats and sailing ships, where motorized aids are usually not available, and the task must be performed manually. The block and tackle pulley was invented by Archimedes.
Mechanical advantage
The most common arrangement is to have a set of fixed pulleys or "sheaves" all mounted on a single
axle, and another set left to move. Each set is called a "block" (the whole assembly, with the rope, is the "tackle"). The
mechanical advantage of a block and tackle is equal to the number of lines running between the two blocks. For example, a tackle consisting of three fixed and three moving pulleys has six lines going between the pulleys, which gives it a mechanical advantage of 6. This enables the lifting of weights six times heavier than would be possible otherwise.
Friction
The increased force produced by a tackle is offset by both the increased length of rope needed and the friction in the system. In order to raise a block and tackle with a mechanical advantage of 6 a distance of 1 metre, it is necessary to pull 6 metres of rope through the blocks. Frictional losses also mean there is a practical point at which the benefit of adding a further sheave is offset by the incremental increase in friction which would require additional force to be applied in order to lift the load. Too much friction may result in the tackle not allowing the load to be released easilyFriction may mean that the rope in a tackle "bunches" and jams when the force is released if the tackle has too much friction for the load to balance, or that the tackle does not "lower" the load, or by the reduction in force needed to move the load being judged insufficient because undue friction has to be overcome as well.
Friction may sometimes be useful, for example in absorbing the recoil of a
gun laying#Muzzle Loading Artillery.
Rigging methods
A tackle may be
- "Rigged to advantage" - where the pull on the rope is in the same direction as that in which the load is to be moved
- "Rigged to disadvantage" - where the pull on the rope is in the opposite direction to that in which the load is to be moved
While it may seem logical to rig to advantage in every case, the decision of which to use depends on pragmatic considerations for the total
ergonomics of working with a particular situation.
See also
Notes
References
- Rescue Technician: Operational Readiness for Rescue Providers, edited by Claire Merrick et al., published by Mosby, Inc., St. Louis, Mo., 1998, copyright held by Maryland Fire and Rescue Institute. ISBN 0-8151-8390-9 See Chapters 4 and 5, p. 41 and ff.
External links
HowStuffWorks "How a Block and Tackle Works"
A fascinating article that describes how a block and tackle (as well as levers and gears) works! ... Please copy/paste the following text to properly cite this How Stuff Works ...
Block and tackle - Wikipedia, the free encyclopedia
A block and tackle [1] is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift or pull heavy loads.
AskOxford: block and tackle
block and tackle • noun a lifting mechanism consisting of ropes, a pulley block, and a hook. Perform another search of the Compact Oxford English Dictionary
block and tackle - Hutchinson encyclopedia article about block and ...
They divided it into cakes by methods too well known to require description, and these, being sledded to the shore, were rapidly hauled off on to an ice platform, and raised by ...
Rijdat Software - Block & Tackle
Block & Tackle - Napoleonic Naval Strategy Game ... Block & Tackle is a simple Napoleonic naval strategy game based on the ships and equipment available around the time of the ...
Block And Tackle
rompstore for kids and grown ups too! the US source for inke heiland's wallpaper menagerie ... want this as a gift? tell someone!
hackwriters.com - Block and Tackle by Mark Cunliffe
Block and Tackle • Mark Cunliffe It is often said that two is company Three however leads you into deep shit. Guy Block, lecturer in English Literature ...
block and tackle - definition of block and tackle by the Free Online ...
An apparatus of pulley blocks and ropes or cables used for hauling and hoisting heavy objects.
Football Block Tackle Technique
the block tackle an important football technique ... The football block tackle technique is an essential skill, because any team must be able to win the ball.
Klein Block and Tackle, Hooks
Klein Tool Block and Tackle, Hooks for sale at discount prices ... Klein offers a quality line of Block, Tackle and Hooks. Ranging from blocks with rope and standard / guarded snap ...
