Cylinders and Actuators

1
Cylinders and Actuators

• Single Acting
• A single acting cylinder develops thrust in one
  direction only
• The piston is usually returned by a spring, but
  can be returned
• by some external means as well(ex. vertical
  load)

2
Cylinders and Actuators

• Single Acting
• A single acting cylinder develops thrust in one
  direction only
• The piston is usually returned by a spring, but
  can be returned
• by some external means as well(ex. vertical
  load)
• Advantages
• lower air consumption compared to double acting
• 3 way valve needed instead of 4 way (lower
  cost)

3
Cylinders and Actuators

• Single Acting
• A single acting cylinder develops thrust in one
  direction only
• The piston is usually returned by a spring, but
  can be returned
• by some external means as well(ex. vertical
  load)
• Advantages
• lower air consumption compared to double acting
• 3 way valve needed instead of 4 way (lower
  cost)
• Disadvantages
• Reduction in piston thrust
• Longer length body due to size of spring

4
Single Acting Spring Return
5
Single Acting Spring Return
Rest state. No pressure applied. Cylinder is
retracted.
6
Single Acting Spring Return
Rest state. No pressure applied. Cylinder is
retracted.
Air pressure applied. Cylinder extends. Spring is
compressed.
7
Single Acting
Spring Return
Rest state. No pressure applied. Cylinder is
retracted.
Air pressure applied. Cylinder extends. Spring is
compressed.
Air pressure exhausted. Cylinder retracts due to
the force of the spring and is returned to rest
state.
8
Single Acting
Spring Extend
Rest state. No pressure applied. Cylinder is
extended.
9
Single Acting Spring Extend
Rest state. No pressure applied. Cylinder is
extended.
Air pressure applied. Cylinder retracts.
Spring is compressed.
10
Single Acting Spring Extend
Rest state. No pressure applied. Cylinder is
extended.
Air pressure applied. Cylinder retracts.
Spring is compressed.
Air pressure exhausted. Cylinder extends due to
the force of the spring and is extended to rest
state.
11
Double Acting Cylinders
Thrust is developed in both extending and
retracting directions as air pressure is applied
to the appropriate ports.
12
Double Acting Cylinders

• Thrust is developed in both extending and
  retracting directions
• as air pressure is applied to the appropriate
  ports.
• Advantages
• More compact body when compared to single
  acting
• Higher force with smaller bore size due to
  absence of spring

13
Double Acting Cylinders

• Thrust is developed in both extending and
  retracting directions
• as air pressure is applied to the appropriate
  ports.
• Advantages
• More compact body when compared to single
  acting
• Higher force with smaller bore size due to
  absence of spring
• Disadvantages
• Force on retraction(piston rod side) is
  different than the
• extension due to the reduced surface area where
  the
• piston rod attaches to the piston

14
Double Acting
Cylinder is at rest when neither port is
energized.
A B
15
Double Acting
Cylinder is at rest when neither port is
energized.
A B
When A is pressurized the piston extends out and
B exhausts air.
16
Double Acting
Cylinder is at rest when neither port is
energized.
A B
When A is pressurized the piston extends out and
B exhausts air.
When B is pressurized, the piston retracts and A
exhausts air. The cylinder is now back to its
original state.
17
Variations in Cylinders
Double Rod Type

• Tandem Type

1
2
3
18
Variations in Cylinders
Double Rod Type
19
Variations in Cylinders
Double Rod Type

• Tandem Type

1
2
3
20
Rodless Cylinders
Rodless cylinders can typically be installed in
1/2 the space of that of a standard cylinder.
They are offered in much longer strokes and
have higher side load capabilities.
21
Rodless Cylinders

• Rodless cylinders can typically be installed in
  1/2 the space of that of a standard cylinder.
  They are offered in much longer strokes and
  have higher side load capabilities.
• Magnetically Coupled
• The cylinder is coupled to the piston by
  magnetic force
• requiring no physical attachment between the
  body
• and the piston. Coupling permits smooth load
  transfer without allowing seal contamination.

22

• Mechanically Coupled(Band Cylinder)
• The cylinder is joined by a lip sealing
  mechanism suited for
• very high loads while maintaining high accuracy.
  It
• has much higher side load capabilities but is
  not as totally
• leak free when compared to the magnetically
  coupled type.

23
Slide Units

• Commonly used in very precision type
  applications which
• require compact and low profile dimensions.
  Precisely
• machined work mounting surfaces and parallel
  piston
• guide rods ensure accurate and straight line
  movement.

24
Slide Units

• Commonly used in very precision type
  applications which
• require compact and low profile dimensions.
  Precisely
• machined work mounting surfaces and parallel
  piston
• guide rods ensure accurate and straight line
  movement.
• Either the body can be fixed and the rods with
  end bars
• can move or the end bars can be fixed and the
  body can
• move

25
Air Chucks (Grippers)
Designed to grip components using 2, 3, or 4
fingers
26
Rotary Actuators

• Rack and Pinion Type
• The output shaft has an integral pinion gear
  driven by a
• a rack attached to a double piston. Standard
  angles of
• rotation are 90 and 180.

27

• Vane Type
• Air pressure acts on a vane which is attached
  to the
• output shaft. The vane is sealed against
  leakage by
• a lifted rubber seal or elastomer coating.
  Standard
• angles of rotation are 90, 180 or 270.

28
Cushioning
In certain applications, it is necessary to
specify air cushions or shock absorbers due to
high speeds and considerable end of stroke
forces.
29
Cushioning

• In certain applications, it is necessary to
  specify air cushions
• or shock absorbers due to high speeds and
  considerable
• end of stroke forces.
• Rubber Cushions
• Often used on smaller size bore and stroke
  cylinders to absorb
• shock and prevent internal damage.

30
Cushioning

• In certain applications, it is necessary to
  specify air cushions
• or shock absorbers due to high speeds and
  considerable
• end of stroke forces.
• Rubber Cushions
• Often used on smaller size bore and stroke
  cylinders to absorb
• shock and prevent internal damage.
• Adjustable Air Cushions
• Often used on larger size bore and stroke
  cylinders to decelerate
• the piston over the last portion of the stroke.
  This cushion
• traps some of the exhausting air near the end of
  the stroke
• before allowing it to bleed off slowly through an
  adjustable
• needle valve.

31

• Special Sine Cylinder Cushion
• Rapid load transfer while allowing smooth
  acceleration
• and deceleration of load which dramatically
  reduces
• shock/impact.

32

• Special Sine Cylinder Cushion
• Rapid load transfer while allowing smooth
  acceleration
• and deceleration of load which dramatically
  reduces
• shock/impact.

• Shock Absorbers
• Used for very high speed and heavy load
  applications
• to consistently decelerate loads without
  requiring
• additional adjustment. Can withstand impacts of
• 16 ft/second.

33
Cylinder Options

• Locking Cylinder
• - Allows for /- .5mm incremental stopping
  accuracy

34
Cylinder Options

• Locking Cylinder
• - Allows for /- .5mm incremental stopping
  accuracy

• Non-Rotating
• - Prevents piston rod and the load from
  rotating

35
Cylinder Options

• Locking Cylinder
• - Allows for /- .5mm incremental stopping
  accuracy

• Non-Rotating
• - Prevents piston rod and the load from
  rotating
• Low Friction/Low Speed
• - Special internal seals and lubricants allows
  speeds
• of 2mm per second

36
Cylinder Options

• Locking Cylinder
• - Allows for /- .5mm incremental stopping
  accuracy

• Non-Rotating
• - Prevents piston rod and the load from
  rotating
• Low Friction/Low Speed
• - Special internal seals and lubricants allows
  speeds
• of 2mm per second

• High Speed
• - Enlarged orifices are added to maximize speed

37

• Copper Free
• - all components can be electroless nickel
  plated for
• copper free environments

38

• Copper Free
• - all components can be electroless nickel
  plated for
• copper free environments
• High Temperature
• - up to 300F applications

39

• Copper Free
• - all components can be electroless nickel
  plated for
• copper free environments
• High Temperature
• - up to 300F applications
• Low Temperature
• - down to -58 F applications

40

• Copper Free
• - all components can be electroless nickel
  plated for
• copper free environments
• High Temperature
• - up to 300F applications
• Low Temperature
• - down to -58 F applications
• Heavy Duty Rod
• - enlarged piston rod for heavy side load
  applications

41

• Copper Free
• - all components can be electroless nickel
  plated for
• copper free environments
• High Temperature
• - up to 300F applications
• Low Temperature
• - down to -58 F applications
• Heavy Duty Rod
• - enlarged piston rod for heavy side load
  applications
• Adjustable Stroke
• - allows final extension or final retraction to
  be
• adjusted

42

• Auto Switch Mount
• - allows stroke feedback/conformation to
  controller to
• confirm work has been completed

43

• Auto Switch Mount
• - allows stroke feedback/conformation to
  controller to
• confirm work has been completed
• High Magnetic Field Capability
• - special auto-switches and internal magnets
  allow
• cylinder to be used in applications 2 away
• from magnetic field displacing 20,000 Amps

44
Determining Which Cylinder Bore Size to Use
For a double acting cylinder Extending Stroke
Fe (p / 4) D² x P Retraction Stroke Fr
(p / 4) (D²-d²) x P For a single acting
cylinder Extending Stroke Fes (p / 4) D²
x P - Fs D Piston Diameter F Force d
Piston Rod Diameter Fs Spring Force at the End
of Stroke P Gauge Pressure