1. Inclined Plane, Wedge, and Screw
Simple Machines
Inclined Plane, Wedge, and Screw

2. The Six Simple Machines
Mechanisms that manipulate force and distance.
Pulley
Lever
Wheel and Axle

3. Inclined Plane
Wedge
Screw

4. Inclined Plane
A flat surface set at an angle or incline with no moving parts
Able to lift objects by pushing or pulling the load

5. Inclined Plane AMA What is the AMA of the inclined plane above?
50. lbs
4 ft
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?
= 0.67 or 67%
Efficiency =

6. Wedge 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)

7. Wedge IMA What is the IMA of the wedge on the right?
H in.
L in.
DE = Distance traveled by the effort = L
DR = Distance traveled by the resistance = H
What is the IMA of the wedge on the right?
IMA = 10.0 in. / 3.0 in. = 3.33 = 3.3:1

8. Wedge AMA What is the AMA of the wedge on the right?
250. lb
H in.
L in.
What is the AMA of the wedge on the right?
700. lb
700. lb
AMA = 2.80 = 2.80:1
What is the efficiency of the wedge on the right?
Efficiency =
= 0.84 or 84%

9. Screw Two Components: Properties:
An inclined plane wrapped around a cylinder, forming the screw’s “pitch”
A wheel and axle used to create rotary motion
Properties:
Change rotary motion into linear motion
Used as a threaded fastener
Large amount of friction loss (is this good or bad?)
Large MA

10. Screw Identification
Diameter
Effort Arm Distance If using a wrench, effort arm distance would be the length of the wrench
Pitch
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

11. Screw Identification 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)
Length in inches (Optional)
Metric Thread Information
M3 x 0.5 x 30
Outside diameter of screw shaft (mm)
Pitch
(mm per thread)
M = Metric
Length in mm (Optional)

12. Screw Identification Unified Thread Information #4 x 40 x 2.0 NC
Outside diameter of screw shaft (inches)
Pitch
(TPI)
Thread description coarse or fine
(Optional)
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" " X (numbered diameter)
Example: A #2 has a major diameter of 0.086"

13. Screw IMA
1/4 20 NC
DE = One rotation of the effort = Circumference
DR = Linear distance traveled during one rotation = Pitch
What is the IMA of the screw above if effort is applied by an 8.0in. long wrench?

14. Screw AMA What is the AMA of the screw? AMA = 34.29 = 34:1
8 in.
1/4 20 NC
35 lb
What is the AMA of the screw?
1200 lb
AMA = = 34:1
What is the efficiency of the screw?
= or 3.4%
Efficiency =
Why is efficiency so low?

15. Compound Machines
Simple machines working in combination to complete a task
Calculating mechanical advantage

16. Image Resources
Microsoft, Inc. (2008). Clip Art. Retrieved January 10, 2008, from