The chain hoist has either a lever to power the hoist or a loop of operating chain pulls through the block of the hoist which then powers the block that takes up the main lifting chain.
Aside from the gearing which provides the 30 to 1 mechanical advantage, the principle is based on the physics definition of WORK. That is, WORK = FORCE x DISTANCE. In this case you use say 1 lb of force a distance of 30 inches (the 30 to 1 mech advantage) or 30 lb-in of work which is equivalent to having lifted 30 lb 1 in, 30 lb-in as well, without the mechanical advantage.
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.
This is infuriatingly incorrect. There is minimal stress on the first, 5-tooth gear. The twin gears aren't there to help that guy out. They exist to distribute the load of the next stage, the load on the 4 tooth gears. Those are under much higher stress. Notice how thick those 3 gears are compared to the others.
+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.
@@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.
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.
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
Thanks for the video!
Thank You, Very Conceptual Video👍👍
Very good video. Thanks.
Just awesome explanations
The chain hoist has either a lever to power the hoist or a loop of operating chain pulls through the block of the hoist which then powers the block that takes up the main lifting chain.
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
what kind of metal used is it hard steel or just iron ?
Can you swap out the chain and use rope? 50 foot lift. For hoisting yourself up a mast and you have a halyard on a sheave at top.
.
Importantisssimo vid.
Aside from the gearing which provides the 30 to 1 mechanical advantage, the principle is based on the physics definition of WORK. That is, WORK = FORCE x DISTANCE. In this case you use say 1 lb of force a distance of 30 inches (the 30 to 1 mech advantage) or 30 lb-in of work which is equivalent to having lifted 30 lb 1 in, 30 lb-in as well, without the mechanical advantage.
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.
Thanks, good job
nice demonstration
Really it is good
Nice video
Everybody wonders that but nobody ever gives a good answer.
For your SAFETY!!! Take care for Chinese Chain Hoist.
excellent
Well explained, Thank you
Fuc**ng awesome invention.
I've never taken apart a chain hoist myself. Then again I've never had to climb up and release the "dog" they show holding that gear either.
Nice
This is infuriatingly incorrect. There is minimal stress on the first, 5-tooth gear. The twin gears aren't there to help that guy out. They exist to distribute the load of the next stage, the load on the 4 tooth gears. Those are under much higher stress. Notice how thick those 3 gears are compared to the others.
Gotta love that 80s metal soundtrack during the disassembly segment.
You know they mean business when they play that.
Nice
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How does brake work??
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
Why did he use bolt cutters on the hand chain if he was taking it apart anyway?
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Tenks
That break.
It can only stops in one direction.
What about the other direction of pulling the chain....?
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.
How you calculate that it can raise 30 times more load than the effort??
7/5 x 18/4 x 19/4
Can anyone give its velocity ratio calculations??
Chain kuppe line h bhai kaha milege
How many tons could it lift ?
I've seen it at work. It lefts 2 tons, but I don't know if they are limited to such weight
How much amount pls
I think the Larger gear is moving slow than the Smaller Gear, the pull of man should be at the small gear, just commenting
The reason for this is to and another weight reduction. It's a concept similar to that of the wheel and axle.
How does sit lower without engaging the ratchet pawl?
Check out the video "Automatic brake in spur gear hoist" and read the expiation.
a glutch
I got 17.1 times force with my calculations. Ofc I had to use an assumed torque of 55.6Nm
Can you please give the calculation??
How about backward
+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.
Gotta keep those 12 year olds interested with cheesy montage and music.
WHY HAND CHAIN ISNT DRIVE WITH SOME KIND OF SMALL ELECTRIC MOTOR??
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.
My hoist want release
So many time I floo that i never understand that
So, dude, when you turn the chaiin the other way to lower it, how does it do it against the ratcheting pawl? Explain that.....
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
30:1 got it