Machine Design Databook Episode 2 part 9 doc

Breakingstrengthweight of rope, min weight of rope, min weight of rope, min weight of rope, minDiameter N/m kgf/m kN kgf N/m kgf/m kN kgf N/m kgf/m kN kgf N/m kgf/m kN kgf FLEXIBLE MACHI

Trang 1

TABLE 21-37

Round strand galvanized steel wire ropes for shipping purposes

Tensile strength of wire, 1373–1569 MPa (140–160 kgf/mm2)

Approx

Breakingstrength Approx

Breakingstrengthweight of rope, min weight of rope, min weight of rope, min weight of rope, minDiameter N/m kgf/m kN kgf N/m kgf/m kN kgf N/m kgf/m kN kgf N/m kgf/m kN kgf

FLEXIBLE MACHINE ELEMENTS 21.61

Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)

Trang 2

TABLE 21-38

Dimensions and breaking strength of ﬂat balancing wire ropes

b s,a

Diameter section of Double-stitched Single-stitched of ropeDouble- Single- of the the strand,

Constructions stitched stitched wire, mm mm2 N/m kgf/m N/m kgf/m kN kgf

Trang 3

TABLE 21-39

Dimensions and breaking strength of ﬂat hoisting wire ropes

Minimum breakingCross section Weight strength of ropeaNominal size, Nominal wire of strand,

Trang 4

TABLE 21-40

Tensile grade

Tensile strength range

Values of C for wire ropes

Approximate wire rope and sheave data

SI units: d ¼ diameter of rope, m

US Customary units: d ¼ diameter of rope, in

Trang 5

Steel-mill ladles

Cranes

High speed elevators

21.65Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)

Trang 6

TABLE 21-44

Recommended safety factors for wire ropes

Safety factor

100 or other ﬁgure laid down by the statutory authority

From Indian Standards

Ropes which are straight between terminal ﬁttings

Hoisting, luﬃng and reeved bridle systems of inherently ﬂexible crances

(e.g., mobile crawler tower, guy derrick, stiﬄeg derrick) where jibs are

supported by ropes or where equivalent shock absorbing devices are

incorporated in jib supports

From Other SourcesMine Shafts

hoisting equipment 8 19 ﬁller wire

Trang 7

The working load for the ordinary steel BB crane

chain

The sheave diameter

Round steel short link and round steel link chain

LENGTH AND WIDTH (Figs 21-17 and 21-18):

The outside dimensions of the links shall fall between

the following limits:

Outside link length limits (Fig 21-17)

Maximum outside link width (Fig 21-18)

Minimum inside link width

Pitch (i.e., inside length)

Dimensions and lifting capacities and properties of

noncalibrated and calibrated chains

where d in m and Pwin kN

Pw¼ 13;600d2

USCS ð21-79bÞ where d in in and Pwin lbf

Pw¼ 9:56d2

Customary Metric ð21-79cÞ where d in mm and Pwin kgf

l j> 5dn for uncalibrated chain ð21-81aÞ

l j < 6dn for calibrated chain ð21-81bÞ

Wmaxj> 3:5dn away from weld ð21-82aÞ

Wmaxj> 1:05 (adjacent width) at weld

for noncalibrated chains ð21-82bÞ

Wmax¼ 3:25dn for calibrated chain ð21-83Þ

Wt j< 1:25dn except at the weld for

noncalibrated chain ð25-84Þ

p ¼ 3dn for calibrated chain ð21-85Þ Refer to Tables 21-46 to 21-51.

FIGURE 21-17 Diameter of material and welded chain

Trang 12

TABLE 21-50

Requirements of arc welded grade 30 chain for lifting purposes

Minimum energyMinimum breaking load absorption factor for 1-m Maximum safe workingProof load based on based on a stress of gauge length based on an load for nominal workingSize a stress of 294.2 MPa energy absorption of 58.8 condition based on a stress(nominal 98.1 MPa (10 kgf/mm2) (30 kgf/mm2) MN-m/m2(6 kgf-m/mm2) of 49 MPa (5 kgf/mm2)diameter),

Trang 13

Chain passing over a sheave (Fig 21-19)

The eﬀort on the chain in case of single-sheave pulley

(Fig 21-19)

The eﬃciency of the chain sheave

FIGURE 21-18 Pitch length and width of link

FIGURE 21-19 Chain passing over sheave

Diﬀerential chain block (Fig 21-20)

RAISING THE LOAD Q

The eﬀort required for raising the load without

friction

The relation between the tension in the running-oﬀ

and running-on chains

The tension in the running-oﬀ chains

The tension in the running-on chain

where C ¼ 1:04 for lubricated chains

C ¼ 1:10 for chains running dry

¼ 1

where ¼ 0:96 for lubricated chains

¼ 0:91 for chain running dry

FIGURE 21-20 Diﬀerential chain block

Po¼ Q

where n ¼ d

D ¼ r R

Trang 14

The relation between eﬀort (P), load (Q), T1and T2

The eﬀort required for raising the load with friction

The eﬃciency for the diﬀerential chain hoist

Lowering the load

The equations for the tension in the running-on

running-oﬀ and pull (P0) required on the chain so as

to prevent running down of the load

The pull required on the chain so as to prevent

running down of the load

The eﬃciency for the reversed motion

For mechanical properties of the coil link chain and

the strength of hoisting chains in terms of bar from

which they are made

Trang 15

Conditions for self-locking of diﬀerential

chain block

The condition for self-locking

For self-locking diﬀerential chain block

The initial value of the ratio r

R

Power chains

Roller chains

The transmission ratio

The average speed of chain

P0¼ Q C

TABLE 21-52

Mechanical properties of the coil link chain

Requirement

Mean stress at guaranteed minimum breaking load, Fwmin, h bar 30 40

Ratio of proof load of guaranteed minimum breaking load 50% 50%

Guaranteed minimum elongation at fracture, A min 14.4% 14.4%

Guaranteed minimum energy absorption factor, Fw A 0.054 kJ m1mm2 0.054 kJ m1mm2

Trang 16

The empirical formula for pitch

Bartlett formula relating speed (n1) and pitch ( p)

based on allowable amount of impact between a

roller and a sprocket

Maximum allowable chain velocity based on Eq.

(21-107)

p 0:25

900

n1

2=3

SI ð21-106aÞ where p in m

p

900

n1

2=3

USCS ð21-106bÞ where p in in

p 250

900

ffiffiffiffiffiffiffiffiffi A

wfp

s

SI ð21-107aÞ where n1in rpm, p in m, wf in N/m, and A in m2

n1¼ 11 ;800 p

wfp

s

USCS ð21-107cÞ where

wfp

s

SI ð21-108aÞ where vmaxin m/s, A in m2, p in m, and wf in N/m

vmax 160z1

Trang 17

Maximum speed based on the energy of impact per

tooth per minute

Maximum chain velocity based on Eq (21-109), m/s

Maximum sprocket speed based on the eﬀect of

centrifugal force

where vmaxin ft/min, A in in2, p in in, and wfin lbf/ft

vmax 0:196z1

ﬃﬃ A

wfp

s Customary Metric ð21-108cÞ

where vmaxin m/s, A in mm2, p in mm, and wf in kgf/m

n 1437 p

3

ffiffiffiffiffiffi A

wf

s

SI ð21-109aÞ where A in m2, p in m, and wf in N/m

n 2000 p

3

wf

s

USCS ð21-109bÞ where A in in2, p in in, and wf in lbf/ft

n 6712 p

3

wf

s

Customary Metric ð21-109cÞ where A in mm2, p in mm, and wf in kgf/m

vmax 24z1

3

wf

s

SI ð21-110aÞ where vmaxin m/s, A in m2, and wf in N/m

vmax 166z1

3

wf

s

USCS ð21-110bÞ where vmaxin ft/min, A in in2, and wf in lbf/ft

vmax 0:11z1

3

wf

s

Customary Metric ð21-110cÞ where vmaxin m/s, A in mm2, and wf in kgf/m

n 36350 p

ffiffiffiffiffiffiffiffiffiffi A

z1wf

s

SI ð21-111aÞ where p in m, A in m2, and wf in N/m

n 9516 p

ffiffiffiffiffiffiffiffiffiffi A

z1wf

s

USCS ð21-111bÞ where p in in, A in in2, and wf in lbf/ft

Trang 18

Maximum velocity based on Eq (21-111)

Chain pull

For preliminary computation, the allowable pull

AGMA formula for allowable pull based on

velocity factor Cv¼ 3=ð3 þ vÞ and bearing pressure

of 29.4 MPa (4333 psi) for the pin

For dimensions of American Standard Roller

Fa¼ Fu

no

ð21-113Þ where

Fu¼ ultimate strength from Tables 21-35B and 21-42

l ¼ length of roller pins, m (in)

Trang 19

TABLE 21-54A

Dimensions of American Standard roller chains—single-strand

ANSI chain Minimum tensile Average weight, Roller diameter, Multiple-strandnumber Pitch, in (mm) Width, in (mm) strength, lb (N) lb/ft (N/m) in (mm) spacing, in (mm)

Source: Compiled from ANSI B29.1-1975

Trang 20

TABLE 21-54B

Rated horsepower capacity of single-strand single-pitch roller chain for a 17-tooth sprocket

ANSI chain numberSprocket speed,

Estimated from ANSI tables by linear interpolation

Note: Type A—manual or drip lubrication, type B—bath or disk lubrication; type C—oil-stream lubrication

Source: Compiled from ANSI B29.1-1975 information only section, and from B29.9-1958

Trang 21

TABLE 21-54C

Rated horsepower capacity of single-strand single-pitch roller chain for a 17-tooth sprocket

ANSI chain numberSprocket

Tooth correction factors, K1

Trang 22

For the rated horsepower capacity of

single-strand-single-pitch roller chains for 17-tooth sprocket and

values of K1and K2

Power required

Refer to Tables 21-54B to 21-54E.

P ¼ Fv 1000klks

SI ð21-115aÞ where Fin N and P in kW

P ¼ 33;000k Fvlks

USCS ð21-115bÞ where Fin lbf and P in hp

P ¼ Fv 102klks

Customary Metric ð21-115cÞ where

F¼ required chain pull in kgf and P in kW

kl¼ load factor from 1.1 to 1.5 and also obtained from Chap 14

ks¼ service factor

¼ 1 for 10 h service per day

¼ 1.2 for 24 h operation and also obtained from Table 21-54F

Service factor for roller chains, ks

Intermittent few hours per Normal 8 to 10 hours per ContinuousOperating characteristics day, few hours per year day 300 days per year 24 hours per dayEasy starting, smooth, steady load 0.06–1.00 0.90–1.50 0.90–2.00Light medium shock or vibrating load 0.90–1.40 1.20–1.90 1.50–2.40Medium to heavy shock or vibrating load 1.20–1.80 1.50–2.30 1.80–2.80

Trang 23

The rated horsepower of roller chain per strand

The corrected horsepower (Pc)

CHECK FOR ACTUAL SAFETY FACTOR

The actual safety factor checked by the formula

The number of strand in a chain, if F> Fa

Center distance of chain length

The proper center distance between sprockets in

w ¼ weight per meter of chain, N (lbf )

v ¼ velocity of chain, m/s (ft/min)

C ¼ center distance, m (in)

ksz¼ coeﬃcient for sag from Table 21-55

i ¼ F

Cp¼ 20p to 30p or Cp¼ 40 10 pitches ð21-119Þ where pCp¼ C

Coeﬃcient for sag, ksg

Position of chain driveksg Horizontal <408 >408 Vertical

Trang 24

The maximum center distance

The chain length in pitches

The chain length, m or in

tan

180 z

z1¼ number of teeth on a small sprocket

z2¼ number of teeth on a large sprocket

¼ angle between tangent to the sprocket pitch circle and the center line

Minimum center distance constant, Kmin

Transmission ratio,i Minimum center distance constant,Kmin

Trang 25

The chain length

The pitch diameter of a sprocket

Roller chain sprocket

Minimum number of teeth

Silent chain sprocket

Minimum number of teeth

The root diameter of sprocket

The width of sprocket tooth (Fig 21-22)

Maximum hub diameter

Power per cm of width in hp

The relationship between depth of sag, and tension

due to weight of chain in the catenary (approx.)

sin

180 z

ð21-133bÞ where

h ¼ depth of sag, m (in)

L ¼ distance between points of support, m (in)

S ¼ catenary length of chain, m (in)

F ¼ tension or chain pull, kN (lbf )

w ¼ weight of chain, kN/m (lbf/in)

Trang 26

Tension chain linkages

FIGURE 21-21 Notation for wheel rim of chain

Wheel tooth gap form

The minimum value of roller seating radius, mm

sin 180 z

Trang 28

FIGURE 21-23 Notation for tooth gap form of roller

Tooth heights and top diameters (Fig 21-23)

The maximum limit of the tooth height above the

pitch polygon

The minimum limit of the tooth height above the

pitch polygon

The maximum limit of the tooth top diameter, mm

The minimum limit of the tooth top diameter, mm

FIGURE 21-24 Notation for minimum tooth gap form ofroller chain

Trang 31

Wheel rim proﬁle (Fig 21-22)

Tooth width

The minimum tooth side radius

The tooth side relief

Absolute maximum shroud diameter

For leaf chain dimension, breaking load, anchor

clevises and chain sheaves

The maximum limit of the tooth top diameter

The minimum limit of the tooth top diameter

The maximum limit of the tooth height above the

sin 180 z

Trang 36

Cranked link dimensions

Width over bearing pins

Trang 38

TABLE 21-66

Recommended design data for silent chains

No of teethChain pitch, mm Speed of small sprocket Driver Driven Min center distance, mm

Maximum velocity for various types of chains, rpm

Number of sprocket teethBush roller chain

Trang 39

FIGURE 21-27 Notation for tooth gap form of bush chain.

FIGURE 21-28 Notation for minimum tooth gap form forbush chain

FIGURE 21-29 Notation for maximum tooth gap form forbush chain

Trang 40

The minimum limit of the tooth height above the

pitch polygon

WHEEL RIM PROFILE (Fig 21-26) The value of

tooth width for simple chain wheels (Fig 21-26)

The value of tooth width for duplex and triplex chain

wheels

The value of tooth width for quadruplex chain wheels

and above

The value of width over tooth

The minimum tooth side radius

The tooth side relief

Absolute maximum shroud diameter

For bush chains dimensions, breaking load, pitch

circle diameters, etc.

REFERENCES

1 Maleev, V L., and J B Hartman, Machine Design, International Textbook Company, Scranton, Pennsylvania, 1954.

2 Black, P H., and O E Adams, Jr., Machine Design, McGraw-Hill Book Company, New York, 1968.

3 Norman, C A., E S Ault, and I F Zarobsky, Fundamentals of Machine Design, The Macmillan Company, New York, 1951.

4 Shigley, J E., Machine Design, McGraw-Hill Book Company, New York, 1962.

5 Shigley, J E., and C R Mischke, Mechanical Engineering Design, McGraw-Hill Book Company, New York, 1989.

6 Shigley, J E., and C R Mischke, Standard Handbook of Machine Design, McGraw-Hill Book Company, New York, 1986.

7 Baumeister, T., ed., Marks’ Standard Handbook for Mechanical Engineers, McGraw-Hill Book Company, New York, 1978.

8 Niemann, G., Maschinenelemente, Springer-Verlag, Berlin; Zweiter Band, Munich, 1965.

9 Niemann, G., Machine Elements—Design and Calculations in Mechanical Engineering, Vol II, Allied Publishers Private Ltd., New Delhi, 1978.

10 Decker, K H., Maschinenelemente, Gestaltung and Berechnung, Carl Hanser Verlag, Munich, 1971.

The value of tolerance shall be h=4.

C2ðor C3Þ ¼ number of strands 1Tpþ C1

ð21-166Þ with a tolerance value of h=4

where Tp¼ transmission pitch of strands

Tiêu đề	Flexible Machine Elements
Trường học	Digital Engineering Library @ McGraw-Hill
Chuyên ngành	Machine Design
Thể loại	Thesis
Năm xuất bản	1968

Định dạng
Số trang	40
Dung lượng	509,38 KB