Inclined Plane, Wedge, and Screw. The Six Simple Machines Mechanisms that manipulate force and...

Inclined Plane, Wedge, and Screw

Simple Machines

Simple Machines

The Six Simple MachinesMechanisms that manipulate force and

distance.Lever Wheel and Axle Pulley

Inclined Plane

ScrewWedge

A flat surface set at an angle or incline with no moving parts

Able to lift objects by pushing or pulling the load

Inclined Plane

4 ft15 ft

50. lbs

20. lbR

E

FAMA =

F

50.lbAMA =

20.lb

What is the AMA of the inclined plane above?

AMA = 2.5 = 2.5:1

What is the efficiency of the inclined plane above?

2.503.75Efficiency = = 0.67 or

67%

Inclined Plane AMA

AMAIMA

• Functions as a moving inclined plane• Tapers to a thin edge• Used for splitting, raising heavy items, or tightening by expansion (being driven into something)

Wedge

Wedge IMA

E

R

DIMA =

D

DE = Distance traveled by the effort = L

DR = Distance traveled by the resistance = H

H 3.0 in.

L

10.

0 in

.

LIMA =

HWhat is the IMA of the wedge on the right?

IMA = 10.0 in. / 3.0 in. = 3.33 = 3.3:1

Wedge AMAH 3.0 in.

L 1

0.0

in

.

250. lb

700. lb700. lb

R

E

FAMA =

FWhat is the AMA of the wedge on the right? 700.lbAMA =

250.lb

AMA = 2.80 = 2.80:1

What is the efficiency of the wedge on the right?

333.3

080.2Efficiency = = 0.84 or 84%

AMAIMA

• An inclined plane wrapped around a cylinder, forming the screw’s “pitch”

• A wheel and axle used to create rotary motion

ScrewTwo Components:

Properties:• Change rotary motion into linear

motion• Used as a threaded fastener• Large amount of friction loss (is this good

or bad?)• Large MA

Pitch

Effort Arm Distance If using a wrench, effort arm distance would be the length of the wrench

Screw Identification

Diameter

Distance between threads, also the linear distance traveled in one rotation of the screw.Example: a screw has 13 threads per inch, 13 TPI for short. The pitch (distance between threads) is 1/13 of an inch.

Q: How far will a screw with 13 threads per inch advance if turned one full rotation?

A: 1/13 of a inch

Standard Thread Information

1/4 x 20 x 3.0 NC

Outside diameter of screw shaft (inches)

Pitch(TPI) Thread

description coarse or fine(Optional)

Screw Identification

Length in inches

(Optional)

M3 x 0.5 x 30

Outside diameter of screw shaft (mm)

Pitch(mm per thread)

M = Metric

Length in mm

(Optional)

Metric Thread Information

Unified Thread Information

#4 x 40 x 2.0 NC

Outside diameter of screw shaft (inches)

Pitch(TPI) Thread

description coarse or fine(Optional)

Screw Identification

Length in inches

(Optional)

• In Unified threads (measured in inches) there are numbered diameters #0 through #10

• #0 the smallest and #10 is the largest

• The major diameter in Unified Threads = 0.060" + 0.013" X (numbered diameter)

• Example: A #2 has a major diameter of 0.086"

Screw IMAE

R

DIMA =

DDE = One rotation of the effort = Circumference

DR = Linear distance traveled during one rotation = Pitch

E2πrCircumferenceIMA = =

Pitch P

1/4 20 NC

What is the IMA of the screw above if effort is applied by an 8.0in. long wrench?

32π8.0inIMA = = 1005.31 = 1.0 •10

1in20

Screw AMA

R

E

FAMA =

F

What is the AMA of the screw?

1200lbAMA =

35lbAMA = 34.29 = 34:1

What is the efficiency of the screw?

3.0510

29.34Efficiency = = 0.0341 or

3.4%

8 in.

35 lb

1/4 20 NC

1200 lb

Why is efficiency so low?

AMAIMA

Compound MachinesSimple machines working in combination to complete a task

Calculating mechanical advantage

1 2MA = ... MA MA MA

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