Calculation force of pulley assembly
Publish: 2021-03-29 17:46:06
1. It should be calculated that half of the force is saved at the end of the movable pulley
when the force at both ends of the rope is calculated, it should be calculated as 100
not
∵ the movable pulley is actually a lever
power arm × Power = drag arm × Resistance
and pull up vertically in the moving pulley, the power arm is equal to the resistance arm
if the maximum bearing force is the power, then the power is equal to the resistance
the material weight is equal to 1 / 2 of the power + resistance
so the maximum bearing force of the rope on the moving pulley should be calculated, which saves half of the force on the other end of the moving pulley
when the force at both ends of the rope is calculated, it should be calculated as 100
not
∵ the movable pulley is actually a lever
power arm × Power = drag arm × Resistance
and pull up vertically in the moving pulley, the power arm is equal to the resistance arm
if the maximum bearing force is the power, then the power is equal to the resistance
the material weight is equal to 1 / 2 of the power + resistance
so the maximum bearing force of the rope on the moving pulley should be calculated, which saves half of the force on the other end of the moving pulley
2. If we use gravity, we use w = GH. If we calculate it by tension, then we calculate it by w = FS. The two are the same; For a moving pulley (ignoring friction and other factors), s = 2H 2F = G
3. When using the fixed pulley, the weight of the fixed pulley is borne by the structure of the fixed pulley, such as the rope, so its weight does not need to be considered.
the weight of the movable pulley is a part of the whole lifting weight, and of course it needs to be calculated
the weight of the movable pulley is a part of the whole lifting weight, and of course it needs to be calculated
4. Cell-padding="-1" cellspacing="-1" style="margin- right:1px ">Wv26377; WW24635;
=
=
26045;-F=
=
=125N
8757F=
| Gh |
| Fs |
| Gh |
| F-2h |
| G |
| 2F |
26045;-F=
| G |
| 2h |
| 150N |
| 2 x60% |
8757F=
| 1
5. In the pulley block, the movable pulley saves labor, so that the number of ropes passing through the movable pulley is the most, and the total rope is connected with the lower part of the fixed pulley, so as to save labor.
6.
(1) Before use, it is necessary to find out its allowable load, check all parts of the pulley to see whether there are cracks and damages, and whether the pulley rotates flexibly (2) in the pulley group, the force should be applied slowly; After the rope is tightened, check whether all parts are in good condition and whether there is any rope clamping. If there is anything wrong, correct it immediately and do not force to work (3) the center of the hook (or ring) of the pulley group should be in a vertical line with the center of gravity of the lifting component, so as to avoid the instability of the component after lifting; The minimum distance between the upper and lower blocks of the block is generally 100-1200mm (4) the pulley group should be cleaned before and after use, and the axle should be lubricated to rece wear and prevent corrosion7. 2 Pulley group
} pulley group is composed of fixed pulley, movable pulley and steel wire rope bypassing them with a certain number of doors< The leading end of the wire rope on the pulley is called "running head", and the end fixed on the splint is called "dead head"; The running head can be led out either by self-determined pulley or by automatic pulley; The dead head can be fixed on the fixed pulley or the movable pulley ★ the number of working ropes supporting the movable pulley on the pulley is called "walking number", which is named according to the number of ropes bypassing the fixed pulley, the number of movable pulley and the number of working ropes. For example, "six six walking thirteen" means that the rope bypasses the pulley block with six fixed pulley, six movable pulley and 13 working ropes "go three go three" means three fixed pulleys and three movable pulleys. 8. There are three groups of two pulleys in each group
9. Use the fixed pulley and movable pulley to make the middle wire rope form four
10. If the fixed pulley does not change the number of load-bearing rope, it will not change the size of the force. The pulley block of a moving pulley (without repeated winding) can enlarge the force by 3 times at most. You can draw by yourself. The key point is that the number of load-bearing rope segments has not changed!
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