The lever is much more useful on loads more then 3 tons unless you can find one cheaper. Otherwise the manual chain is alot easier on your wrist

Really it is good

你的描述很棒，我们可以提供最优质的链条

this is a system that is based on gear reduction ratio (7/5 x 18/4 x 19/4) and not a system of simple pulleys where the mechanical advantage is not the major advantage but a simple leverage as you mention in your question (a torque that is simply created by the distance multiplied by the input force). Gears are much efficient and do indeed provide mechanical advantage.

You know they mean business when they play that.

Rachet system have a reverse tooth gear that doesn't allow the system to move the other way unless a certain key is turned that reverse the pick

I've seen it at work. It lefts 2 tons, but I don't know if they are limited to such weight

7/5 x 18/4 x 19/4

yeah he failed to explain that....some of these videos are junk. I hope somebody fixes this so that people are more than halfway informed.

Check out the video "Automatic brake in spur gear hoist" and read the expiation.

a glutch

Can you please give the calculation??

The reason for this is to and another weight reduction. It's a concept similar to that of the wheel and axle.

+Fadi Koka same thing, but in reverse. Sounds like smart ass answer, but, it's basically true. Look at the clutch that was tightened up at the beginning. Look at the screw threads on the main shaft. When you go backwards, you loosen the clutch and the load slips down. "Why doesn't it freewheel?", you ask. Glad you asked that. :) The load spins the driveshaft which tightens the clutch from the other side, and once the clutch is tight, that pawl(usually there are two pawls in that style of hoist) stops the load from dropping.

@@l337pwnage and how do u detach the clutch from the other side?

@@mahmoudlasheen5762 I think I understand your confusion, but I'm not sure. When raising, the clutch just stays tight and is held by the force of the load against the operator or pawl. The clutch is "pinched" by the force created by the threads the chainwheel threads on to. The only time the clutch slips is when you lower the load. When you lower the load, you are "unpinching" the clutch, but the force of the load quickly spins the gears and the main shaft, which tightens the clutch again, which results in the load being slightly lower.

That's why it has a chain, for manual hand use. Hoists with electric motors don't have a chain.

my tube low duty cycle. Hoists are commonly equipped with electric motors.

These hoists are already fairly heavy, but for mobile use a powered hoist would be prohibitively heavy. Not only are the powered chain hoists heavier, they also take up more space, which can in some circumstances make them useless. And finally, the manual ones are less expensive.

Did u know? I was looking for an answer

It uses a clutch that disengages the hand chain sprocket from the ratchet. Meaning the ratchet and pawl stay stuck but hand chain sprocket can initiate the backwards movement lowering the load. When the hand wheel stops moving the clutch engages and the load stays in place

and that mechanism didn't explained in the video