KI THUẠT VAN CHUYEN C7 co cau thay doi tam voiQUY VĂN
Luffing mechanisms allow cranes to change the reach of their jibs in a vertical plane. There are two main types of luffing mechanisms: wire rope luffing and hydraulic luffing. Wire rope luffing uses wires to raise and lower the jib, while hydraulic luffing uses hydraulic cylinders. The document also discusses calculating the lifting capacity and power of cranes using luffing mechanisms. Formulas are provided for lifting force, power, average velocity, and average power.
This document discusses motive power sources and hoisting mechanisms for cranes.
It describes various motive power sources including electric, internal combustion, hydraulic, and manual drives. For manual drives, it discusses lever and wheel operations placed at ground level or elevated.
It also summarizes electrically-driven and manually-driven hoisting mechanisms. The electrically-driven mechanism typically uses an electric motor connected to a gear reducer and hoisting drum. The manually-driven mechanism uses gearing and levers or wheels to reduce effort and raise loads.
Mathematical equations are provided for calculating torque requirements, speed ratios, and other parameters for hoisting mechanism design and analysis.
KI THUẠT VAN CHUYEN C3 day va cac chi tiet quan huong dayQUY VĂN
1. Wire ropes are composed of individual wires that are subjected to various stresses when in use. A mathematical treatment of all the factors controlling the wires is impractical. Rope design codes are based on maximum tension factors and safety.
2. Lifting tackles are systems using stationary and movable pulleys interlinked by wire ropes to gain mechanical advantage in force or speed. The basic characteristic is the mechanical advantage which is the ratio between the load force and rope force.
3. Drums, pulleys, chains and their attachments are also discussed in detail regarding design, types, and safety factors for hoisting and haulage applications. Standards for selection of proper rope grade and mechanical components are highlighted.
This document discusses various load handling attachments used in cranes, including hooks, hook blocks, grabs, buckets, and lifting magnets. It describes their uses, classifications, materials, design requirements, and operating procedures. Hooks come in different styles like ordinary and ramshorn patterns, and are made of materials like low-carbon steel. Grabs are used to reduce loading time and increase productivity when handling unit loads. Buckets can be single-line or two-line and are used to lift and transport loose materials. Lifting magnets operate on direct current and are suitable for handling steel and cast iron loads. The document provides details on the specifications, calculations, and safety considerations for different load handling attachments.
This document discusses the classification and basic technical specifications of various lifting and conveying equipment. It begins by classifying lifting machines and mechanisms into categories such as hoists, cranes, conveyors, and elevators. It then lists examples of equipment that fall under each category. The document concludes by describing some common technical specifications of lifting equipment, such as load capacity, reach/span, torque, lifting height, and operational speeds. It also discusses utilization rates and performance metrics.
KI THUẠT VAN CHUYEN C7 co cau thay doi tam voiQUY VĂN
Luffing mechanisms allow cranes to change the reach of their jibs in a vertical plane. There are two main types of luffing mechanisms: wire rope luffing and hydraulic luffing. Wire rope luffing uses wires to raise and lower the jib, while hydraulic luffing uses hydraulic cylinders. The document also discusses calculating the lifting capacity and power of cranes using luffing mechanisms. Formulas are provided for lifting force, power, average velocity, and average power.
This document discusses motive power sources and hoisting mechanisms for cranes.
It describes various motive power sources including electric, internal combustion, hydraulic, and manual drives. For manual drives, it discusses lever and wheel operations placed at ground level or elevated.
It also summarizes electrically-driven and manually-driven hoisting mechanisms. The electrically-driven mechanism typically uses an electric motor connected to a gear reducer and hoisting drum. The manually-driven mechanism uses gearing and levers or wheels to reduce effort and raise loads.
Mathematical equations are provided for calculating torque requirements, speed ratios, and other parameters for hoisting mechanism design and analysis.
KI THUẠT VAN CHUYEN C3 day va cac chi tiet quan huong dayQUY VĂN
1. Wire ropes are composed of individual wires that are subjected to various stresses when in use. A mathematical treatment of all the factors controlling the wires is impractical. Rope design codes are based on maximum tension factors and safety.
2. Lifting tackles are systems using stationary and movable pulleys interlinked by wire ropes to gain mechanical advantage in force or speed. The basic characteristic is the mechanical advantage which is the ratio between the load force and rope force.
3. Drums, pulleys, chains and their attachments are also discussed in detail regarding design, types, and safety factors for hoisting and haulage applications. Standards for selection of proper rope grade and mechanical components are highlighted.
This document discusses various load handling attachments used in cranes, including hooks, hook blocks, grabs, buckets, and lifting magnets. It describes their uses, classifications, materials, design requirements, and operating procedures. Hooks come in different styles like ordinary and ramshorn patterns, and are made of materials like low-carbon steel. Grabs are used to reduce loading time and increase productivity when handling unit loads. Buckets can be single-line or two-line and are used to lift and transport loose materials. Lifting magnets operate on direct current and are suitable for handling steel and cast iron loads. The document provides details on the specifications, calculations, and safety considerations for different load handling attachments.
This document discusses the classification and basic technical specifications of various lifting and conveying equipment. It begins by classifying lifting machines and mechanisms into categories such as hoists, cranes, conveyors, and elevators. It then lists examples of equipment that fall under each category. The document concludes by describing some common technical specifications of lifting equipment, such as load capacity, reach/span, torque, lifting height, and operational speeds. It also discusses utilization rates and performance metrics.
1. Chapter IV 1
KYÕ THUAÄT NAÂNG -VAÄN CHUYEÅN
CHÖÔNG IV
CAÙC THIEÁT BÒ PHANH HAÕM
(ARRESTINGGEAR AND BRAKES)
2. Chapter IV 2
1. MUÏC ÑÍCH:
-Theystop the load and hold it when applied to the hoisting motion orbring the
relevantmechanisms at rest within specified braking distances as this is the case on
traveling and slewing motion
4. Chapter IV 4
2. PHAÂN LOAÏI (tt):
Döïa vaøo chöùc naêng (the purpose the brake serves):
Phanh döøng cô caáu ôû cuoái chuyeån ñoäng.( stopping brakes)
Phanh giôùi haïn vaän toác, nhöng khoâng giöõ vaät.( regulating brakes)
Theo tính chaát cuûasöï taùc ñoäng löïc ñieàukhieånphanh
(the mode of applying the brakes-operating force):
Phanh thöôøng ñoùng.( normally -set brakes)
Phanh thöôøng môû.( normally-released brakes)
Phanh tổng hợp.(combination brakes)
5. Chapter IV 5
Purpose
- Arresting gears are the means of sustaining the
load which do not interfere with the hoisting but
prevent it from coming down due to gravity
- Arresting gear in general fall into two basic kinds
which are the ratchet- and- pawl arrangement
and Back- stopping roller clutch
3. CÔ CAÁU KHOÙA DÖØNG
(Arresting gear)
6. Chapter IV 6
3.1 CÔ CAÁU BAÙNH XE COÙC
(Ratchet- and- pawl arrangement)
Nguyeân lyù laøm vieäc:
Cheá taïo:
Baùnhxe: vaät lieäu gang 18-36, theùp
(ñuùc).
Con coùc:theùp 45↑, 40X.
7. Chapter IV 7
3.1 CÔ CAÁU BAÙNH XE COÙC
(Ratchet- and- pawl arrangement)
Caáutaïo:
Taêng cöôøng söï lieân
keát (ñaët vaøi con coùc(a)
Goùc 900 =>
=b/m lớn khi coù va
ñaäp maïnh.
Coù con coùc giaûm oàn
(b)
8. Chapter IV 8
3. CÔ CAÁU BAÙNH XE COÙC(tt):
Tính toaùn.
Xaùcñònh modun: m
}
hoaëc
neáu m > 6 => Kieåm tra [q]
neáu m < 6 => Kieåm tra uoán =>
b].q[P]q[
b
P
q
m.b
Zm
M
D
M
P x
cb
x
.
22
.
]q.[.Z
M2
m x
].[.
2
qD
M
m x
n
x
n
mZ
M
][
...25,2
12
3
9. Chapter IV 9
3. CÔ CAÁU BAÙNH XE COÙC(tt):
Z
M2
m.
m.Z
M2
h.PM xx
u
6
m.)m5,1(
6
b.a
W
22
u
6
m..25,2
W
3
u
][ u
u
u
u
W
M
10. Chapter IV 10
4. PHANH MAÙ (Block brakes)
Block brakes used in hoisting installation
exit in a great number of types
-In most casethey consist of two blocks
arrangedat diametrically opposite points
ofa drum andoperated bylevers
-Braking is effected due to friction setup
fitted to lever of braking system on the
trolley orbridge
11. Chapter IV 11
4. PHANH MAÙ(tt):
a. Phanh moät maù (single-block brake)
Momen phanh:
Nhaän xeùt: b= 0 => P = const.
D.f
M.2
N
2
D
.N.fM
f
f
l
f.bl
.NP 1
12. Chapter IV 12
4. PHANH MAÙ(tt)-hai maù-
Ñaëc ñieåm caáu taïo caàn .
Do N1 N2 =>
S1 S2
=>LöïcuoántruïcS
Ñeå truïc phanh khoâng uoán:
S =0 => b = 0.=> Phanh
coù caàn thaúng.
Momen phanh:
=> ÔÛ phanh caànthaúng =>
bfl
lP
N
.
.
1
1
bfl
lP
N
.
.
1
2
2
11 1. fNS
2
22 1. fNS
b
bfl
fflP
SSS .
.
1...2
222
1
2
21
)(
2
. 21 NN
D
fM f
....
1l
l
DPfM f
13. Chapter IV 13
4. PHANH MAÙ(tt)
Löïcñoùng phanh:
g
f.G
g
c
.
b
a
.NQ
Löïc ñoùng phanh:
b
a
.NK0M 101
e
c
.KK0M 12A
g
f
.G
g
e
KQ0M 202
D.f
M.2
f
F
N x
b. Phanh 2 maù-duøng ñoái troïng
14. Chapter IV 14
4. PHANH MAÙ(tt):
c. Phanh nam chaâm ñieän töø:
(Short-stroke electromagnet brake)
1. Loø xo neùn chính.
2. Loø xo neùn phuï.
3. Nam chaâm ñieän töø.
4. Ñai oác ñieàu chænh loø xo neùn chính.
5. OÁc ñieàu chænh khe hôû maù phanh.
19. Chapter IV 19
5. PHANH ÑAI (BANDBRAKES)
In band brakes, the braking torque is
obtained due to friction of a flexible band
over the surface of a brake wheel.
Band brakes are designed using the well-
known Euler’s formula for a flexible
filament which provides the relationship
between the maximum Sv tension and the
minimum tensions Sr in the band sides
Sv= Sr. ef
20. Chapter IV 20
5. PHANH ÑAI (BAND BRAKES)
a. Phanhñaiñôngiaûn.
( thesimple bandbrake)
1. Baùnh phanh
2. Ñai baèng theùp
3. Caàn
4. Nam chaâm ñieän tö
5. Ñoái troïng
Themaximum tension on the tight side of the band come on fixed
point, renderingthe brake suitable for use with the wheel
always rotating in the same direction
Thesingle band is usedon motion wherethe braking torque varies
with thedirection of rotation, as inthe hoisting mechanism
Nguyeânlyùlaømvieäc:
21. Chapter IV 21
5. PHANH ÑAI (BAND BRAKES)
a. Phanh ñai ñôn giaûn (tt)
( the simple band brake)
Nguyeân taéc : (Enler)
f
21 e.SS
PSS 21 1e
e.P
S f
f
1
1e
P
S f2
Nhaänxeùt: ñeå Mf ↑ => S1↑ => ↑; f ↑
D
M2
P
f
2
D.P
M f
22. Chapter IV 22
5. PHANH ÑAI (tt):
Löïc ñoùng phanh:
Nhaänxeùt: K thay ñoåi ef laàn => Cô caáunaâng.
Löu yù vôùi K xaùcñònh:
M thuaänchieàukim ñoànghoà > M ngöôïc chieàukim ñoànghoà
c
b.G
1ec
e.a.P
K
c
b.G
1ec
a.P
c
b.G
c
a.S
K
0M
f
f
f
2
0
23. Chapter IV 23
5. PHANH ÑAI (tt):
b. Phanhñai vi sai.
( Differential band brake)
Momen phanh:
vôùi
PSS
e.SS
Euler
eaa
GbKc
SM
21
f
21
f
21
20
2
D
KcGb
eaa
1e
M f
21
f
f
2
D
SeS
2
D
PM 2
f
2f
24. Chapter IV 24
5. PHANH ÑAI (tt):
Nhaänxeùt:
=> Mf → : töï ñoùng
Öu ñieåm: cho pheùp K
Nhöôïc ñieåm:
Töï khoùa -> va ñaäp.
Mf thay ñoåi khi thay ñoåi chieàu quay giaûm nhieàu
laàn.
Traùnh töï haõm: a1 > a2.ef [a1 =(2,5 3)a]
f
2
1
e
a
a
)
e.aa
ae.a
( f
21
2
f
1
25. Chapter IV 25
5. PHANH ÑAI (tt):
c. Phanh ñai toång hôïp.
( Reversible band brake)
Löïc ñoùng phanh.
Tröôøng hôïp: a1 = a2 = a
Nhaän xeùt:
a1 = a2 => Mf = const
=> Cô caáudi chuyeån,quay.
a1 <a2 => cô caáunaâng.
c
aSaSbG
KM
)..(.
0 2211
0
)
11
.
(
ff
f
e
P
e
eP
c
a
c
b
GK
26. Chapter IV 26
5. PHANH ÑAI (tt):
Keát luaän:
Kmin : vi sai.
Kmax:toång hôïp.
Vi sai coù tính chaát töï haõm => cô caáuduøng tay.
Ñôngiaûn, toång hôïp => cô caáu naâng.
Toång hôïp (a1 = a2 ) : côcaáudi chuyeån.
Öu nhöôïcñieåm:
Öu:ñôn giaûn, goïn.
Nhöôïc:
Uoántruïc (S1 + S2)
Phaânboáaùplöïc khoângñeàu -> moøn.
Tuoåithoïthaáp.
27. Chapter IV 27
5. PHANH ÑAI (tt):
Phanh ñaitaùc duïng hai chieàu.
Ñaëc ñieåm:
Ñaàu ñai coù Smax luoân coá ñònh.
Löïc taùc duïng ñoùng phanh luoân ôû ñaàu Smin
Ñieåm töïa tay ñoøn thay ñoåi khi thay ñoåi chieàu quay.
Löïc ñoùng phanh giaûm so vôùi phanh toång hôïp.
29. Chapter IV 29
6. PHANH AÙP TRUÏC
(Thrust brakes)
a. Phanhnoùn.(Conebrake)
Caáu taïo:
1. Truïc
2. Baùnh noùn (laéptreân truïc baèng then).
3. Baùnh coùc + maët coân (laép loàng
khoâng).
4. Con coùc.
Nguyeân taéc laøm vieäc:
A salient feature ofthrust brakes is that the load
require to produce the brakingtorqueisdirectedalongtheaxis
ofthebrakeshaft
30. Chapter IV 30
Kieåm tra aùp löïc:
Keát luaän:
vtoác ñoä thay ñoåi phuï thuoäc
D => moønkhoâng ñeàu.
[p] laáy (11,5 kg/cm2 nhöng
khoâng quaù 22.5 kg/cm2 )
][
)(
.4
sin. 2
1
2
2
tb
n
p
DD
K
S
K
S
K
S
N
p
6. PHANH AÙP TRUÏC
(Thrust brakes) tt
31. Chapter IV 31
Tính löïc ñoùng phanh:
Ñieàu kieän phanh:
Treânhình veõ:
=> Keát luaän:
K => ( dính
coân) =>= 150
=> f ↑ (f = 0,3 0,4).
msFP
D
M
P
f.2
PfNFms .
Df
M
N
f
.
.2
sin
K
N sin.
.
.2
Df
M
K
f
6. PHANH AÙP TRUÏC
(Thrust brakes) tt
32. Chapter IV 32
b. Phanh ñóa ( disc brake)
Laø phanh noùn khi = 900.
Muïc ñích:
K khi taêng caëpmaët tieáp
xuùc.
AÙp suaát beà maët:
f
P
NNK 0
90sin.
][
4
)( 2
2
2
1
p
DD
K
S
K
p
6. PHANH AÙP TRUÏC
(Thrust brakes) tt
33. Chapter IV 33
Vôùi Mf chotröôùc: giaûm K baèng phanh nhieàuñóa.
Coù z caëp maët=> Momen 1 maët:
Löïc voøng:
=> Löïc ñoùng phanh:
Keát luaän: K Z laànso vôùi chæ coù 1 caëp tieáp xuùc.
Z
M
M
f
0
DZ
M
D
M
P
f
.
.2.2 0
fDZ
M
f
P
K
f
..
.2
6. PHANH AÙP TRUÏC
(Thrust brakes) tt
35. Chapter IV 35
Brakes for lowering loads also referred to as
weight- operated or load brakes are widely
employed in hand – operated hoists and some
power –driven installation.
The purpose they serve is to stop and hold the load
suspended by applying a torque which is
proportional to the weight of the load hoisted
The braking torque is set automatically by the
torque from load
6. PHANH AÙP TRUÏC
(Thrust brakes) tt
36. Chapter IV 36
c. Phanhaùp truïc töï ñoäng coù maët ma saùt
khoâng taùchrôøi.
(Load brakes operating at a constantfriction
surfacedrag both in lowering and hoisting)
1. Baùnhcoânlieàn moätkhoáivôùi truïcvít.
2. Baùnhcoùckhoeùtmaëtcoânbeântrong.
3. Concoùc.
4. Tayquay.
Löïcñoùng phanh:löïc doïctruïccuûatruïc vít döôùitaùc
duïng cuûatroïnglöôïng vaätnaâng= > Q= const =>maët
phanhluoânkheùpkínkhi naângcuõngnhökhi haï(maët
masaùtkhoângtaùchrôøi).
6. PHANH AÙP TRUÏC
(Thrust brakes) tt
37. Chapter IV 37
Naâng: döôùi taùc duïng Q (1)eùp (2)thaønh moät khoáiquay
theo chieàu naângcaû heäthoáng quay coùc khoâng caûn trôû
chuyeån ñoäng.
Döøng: ngöøng ngay, coùc khoâng cho pheùp cô caáuquay theo
chieàuhaï.
Haï vaät: quay theo chieàu haïMquay thaéng Mf dö giöõa beà maët
coân => maët laøm vieäc bò maøi moøn => chæ duøng trong cô
caáuquay tay.
6. PHANH AÙP TRUÏC
(Thrust brakes) tt
38. Chapter IV 38
Tínhtoaùn:
Phanh duøng trong vaät ñeå taïo momen phanh => thieát keá phanh ñuû ñieàu
kieän => tìm goùc nghieâng baùnh noùn.
Momen phanh caàn thieát:
Töø ñieàu kieän goùc noùn (baøi phanh noùn).
Goùc lôùn hôn goùc ma saùt cuûa maët noùn ñeå traùch dính.
.
i
M
.kM.kM bv
tvp
f.D.
D.sin
M
M
D
M.2
PK
f.D.
sin.2
K
M
n
bv
bv
f
bv
bv
bv
rf
i
.
k
f
.
D
D
sinMM
bv
n
fp
6. PHANH AÙP TRUÏC
(Thrust brakes) tt
39. Chapter IV 39
Löïc ñoùng phanh K laø löïc voøng treân baùnh vít Pbv, maø
Pbv thay ñoåi -> Mbvthay ñoåi Q thay ñoåi
=> Löïc ñoùng phanh K vaø Mf tæ leä thuaän Q.
=> Tính chaát töï ñieàu chænh cuûa phanh => laáy heä soá an toaøn
laáy thaáp (1,2).
Khi haï vaät momen haï phaûi thaéng momen cho.
.
.
i
DQ
M
tg
bv
tvtvfh M1MMM
6. PHANH AÙP TRUÏC
(Thrust brakes) tt
40. Chapter IV 40
c. Phanhaùptruïc töïñoängcoùmaët masaùt
taùchrôøi.
(Load brakesoperating ata reduced friction
surfaceinlowering.)
1. Ñóa laép coá ñònh treântruïc.
2. Baùnh coùc quay töï do.
3. Con coùc
4. Baùnh raêngcoù maët bích ñaëtloàng trong
ñoaïn ren.
5. Vít ñieàu chænh.
Phaïm vi söû duïng: cô caáu naâng daãn ñoäng baèng T
vaø M.
Caáutaïo:chieàu ren ñöôïcchoïn saochodöôùitaùcduïng cuûamomen dotroïnglöôïng vaät
quaboätruyeànbaùnhraêng4 thìbaùnhraêngphaûidòchchuyeåntheochieàu renveà beân
traùieùpchaëtbaùnhcoùc(2) vaø ñóa(1).
6. PHANH AÙP TRUÏC
(Thrust brakes) tt