simple machines inclined plane wedge screw

8/9/2019 Simple Machines Inclined Plane Wedge Screw

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Simple Machines

Inclined Plane, Wedge, & Screw


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Inclined Plane ScrewWedge


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Mechanical Advantage

Ratio of the magnitude of the

resistance and effort forces

Ratio of distance traveled by the effort

and the resistance force

Calculated ratios allow designers to

manipulate speed, distance, force, andfunction


4/19

Mechanical Advantage !ample

ffort force travels " times greater distance than

the resistance force#

Magnitude of $orce%

&istance 'raveled by $orces%

A mechanical advantage of "%( tells us

what about a mechanism)

ffort force magnitude is " times lessthan the magnitude

of the resistance force#


5/19

Mechanical Advantage Ratios

One is the magic numberIf MA is greaterthan (%

Proportionally lesseffort forceis re*uired toovercome the resistance force

Proportionally greatereffort distanceisre*uired to overcome the resistance force

If MA is lessthan (%

Proportionally greatereffort forceis re*uired

to overcome the resistance forceProportionally lesseffort distance is re*uired

to overcome the resistance force

MA can never be less than +ero#


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Ideal Mechanical Advantage IMA-

'heory.based calculation$riction loss is notta/en into consideration

Ratio of distance traveled by effort and

resistance force

0sed in efficiency and safety factor design

calculations

&R 1 &istance traveled by resistance force

&1 &istance traveled by effort force

E

R

DIMA =D


7/19

Actual Mechanical Advantage AMA-

In*uiry.based calculation$rictional losses areta/en into consideration

0sed in efficiency calculations

Ratio of force magnitudes

$1 Magnitude of effort force

$R1 Magnitude of resistance force

R

E

FAMA =

F


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A flat surface set at an angle or incline

with no moving parts

Able to lift ob2ects by pushing or pulling

the load

Inclined Plane


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&1 &istance traveled by the effort 1 3

&R1 &istance traveled by the resistance 1 4

What is the IMA of the inclined plane above)

"#5 ft(6

#5ft

IMA 1 (6#5 ft 7 "#5 ft 1 8#96 1 3.8:1

Inclined Plane IMA

E

R

D

IMA =D

L( slope)IMA =

H


10/19

" ft(6

ft

65# lb

:5#lb

What is the AMA of the inclined plane above)

AMA 1 :#6 1 2.5:1

What is the efficiency of the inclined plane above)

; fficiency 1 1 67%

Inclined Plane AMA

R

E

F

AMA =F

50.lbAMA =

20.lb

2.50100

3.75

AMA100=

IMA


11/19

$unctions as a moving inclined plane

'apers to a thin edge and is used for splitting,raising heavy bodies, or for tightening by being

driven into something

Wedge


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Wedge IMA

&1 &istance traveled by the effort 1 3

&R1 &istance traveled by the resistance 1 4

4 8#5 in#

3

(5#

5

in#

What is the IMA of the wedge on the right)

IMA 1 (5#5 in# 7 8#5 in# 1 8#88 1 3.3:1

E

R

D

IMA =D

L( to height)IMA =

H


13/19

Wedge AMA

4 8#5 in#

3

(5#

5

in#

:65# lb

955# lb 955# lb

What is the AMA of the

wedge on the right)

AMA 1 :#


14/19

An inclined plane wrapped

around a cylinder, forming the

path and pitch

A wheel and a!le used tocreate rotary motion

Screw

!"o #om$onents

Properties

Change rotary motion into linear motion

0sed as a threaded fastener

3arge MA

3arge amount of friction loss


15/19

Pitch

ffort Arm &istance =

If using a wrench, effort arm distancewould be the length of the wrench

'hread Information

(7: (8 >C

&iameter 'hreads

per inch

'hread

description

coarse or fine

If (8 threads per inch, then pitch or distance

between threads is (7(8 of an inch

Screw Identification

&iameter

&istance between threads

and linear distance traveled

by ( rotation of the screw

4ow far will a screw with (8 threads per inch move linearly if

turned one full rotation)

(7(8 of a inch


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Screw IMA

&1 ?ne rotation of the effort arm 1 Circumference

&R1 3inear distance traveled during one

rotation of the effort arm 1 Pitch

(7" :5 >C

What is the IMA of the screw above if effort is applied

by an


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Screw AMA

What is the AMA of the screw on the right)

AMA 1 8"#:@ 1 3:1

What is the efficiency of the screw on the right)

; fficiency 1 1 3.%


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Compound Machines

Simple machines wor/ing in combination

to complete a tas/

Calculating mechanical advantage

( ) ( )( )TTAL 1 2 3MA = MA MA MA ...


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Image Resources

Microsoft, Inc# :55

simple machines inclined plane wedge screw

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