Sheffer C20 SERIES - Manual (Page 2)

Fine grain, high tensile cast iron heads and
caps are the finest that modern foundry
skill can produce. They are machined to
exacting standards.
Piston rods have a minimum expected
yield of 100,000 psi. They are ground, pol-
ished, and hard chrome plated for wear
and corrosion resistance. Four wrench flats
are standard.
The tube is a high tensile, special
Aluminum alloy with a hard anodized fin-
ish. The file-hard finish offers long life and
amazing lubrication holding properties.
Also available in steel and fiberglass.
Maximum strength is obtained through a
prestressed tie rod assembly.
Pistons are machined from a fine grain
alloy cast iron. They are of one piece
design to give full thickness bearing and
engineered for fast, positive inflation of
seals.
Cushion insert sandwiched between the
tube and head (or cap) is sealed with a
pressure-activated O-RING (16A).
Static seals at tube ends are confined, pre-
cision cut gaskets.
Modified U-cup seals are Buna-N com-
pound. They are self-adjusting to pressure
and wear and their design permits simple
replacement – no need to disassemble the
piston from the piston rod.
The replaceable rod bearing is made of oil
impregnated sintered bronze for lubricated
long life.
Synthetic wiper, steel encased, is designed
to wipe off abrasive dust and contaminates
on the retract stroke to insure long life for
packings, rod bearing, and piston rod.
This type of wiper is efficient, has low fric-
tion, and can be replaced without disas-
sembly of the cylinder.
Modified U-cup design offers long life with
minimum friction. It is self-adjusting to
pressure and wear. Seal material is a stan-
dard Buna-N compound. The rod seal can
be replaced without disassembly of the
cylinder.
Is O-Ring sealed and can be rotated to
any position for easy accessibility. When
shipped, cushion adjusting screws will be
in positions 1 and 5 (see PORT POSITIONS
in Rod Ends and Porting Page 7.
A modified U-cup gives positive
sealing during cushioning and free
flow of air for rapid acceleration out of
cushion. No check valve is needed.
C20 Series cylinders can be ordered with
no cushions, cushioned front, cushioned
rear, or cushioned both ends.
1,2 Head and Cap
BORE SIZES 11/2" THRU 10"
Construction
28 24 25 16B
30 31 4 29 43 16A
30 31
14
3
27
21 1
71 33
5 9 18
72 29
2 13
3 Piston Rod
4 Tube
5 Tie Rods
9 Piston
16A Cushion Insert Seals
16B Tube End Seals
18 Piston Seals
21 Rod Bearing
24 Rod Wiper
33
71, 72 Cushions
25 Rod Seal
30 Cushion Adjusting Screw
1 C20-1