Sheffer MH SERIES - Manual (Page 7)

Air Bleeds
An air bleed may be ordered at either
or both ends of the cylinder as an
option. To provide for maximum
bleeding of air from the cylinder,
Sheffer places its air bleeds in the tube
to bleed air from the tube/head or
tube/cap juncture. The air is bled from
the cylinder by backing out the straight
thread metallic seal plug to allow air to
pass by the threads. When air bubbles
stop and oil starts to flow, retighten
plug. It is recommended that bleeding
be done with pressure on the opposite
end of the cylinder so that the bleed
plug is not subjected to pump pressure
when being backed out. Air bleeds
should always be positioned at the
highest point of the cylinder tube.
Please specify positions of air bleeds
by position number from the chart.
NOTE: Since Sheffer puts air bleeds in
the cylinder tube, position can be
changed by loosening the tie rods and
rotating the tube. Photos and Line
Drawings show ports in positions 1
and 5.
Porting
SAE straight thread Ports, located in
positions 1 and 5 (See above) are
standard and will be furnished unless
otherwise specified. Other types and
sizes of ports are available on request,
at slight additional cost.
Port Positions – Where mounting
clearances permit, the ports can be in
any of four positions in the head and in
the cap at no extra cost. Indicate both
port positions desired by position
number. If no preference is stated, ports
will be furnished in positions 1 and 5.
NOTE: The head and cap can be
rotated in relation to each other as
long as mounting and porting are
convenient for installation.
Strongly Recommended
S.A.E. Straight Thread Ports –
S.A.E. straight thread O-ring sealed
ports are standard. This type of port
offers positive seal with full thread
engagement. It also eliminates the
problem of faulty pipe threads since
sealing takes place independently of
the thread. No messy pipe dope to
bother with or to contaminate the
hydraulic system. No wedging,
distortion, or breakage due to over-
tightening. Alignment and full sealing
are both assured since the fittings can
be tightened after lining up. Straight
thread fittings may be reused,
indefinitely. NPT ports are available
at no extra cost.
Cushions – The standard positions
for ports are 1 and 5. Where possible,
the standard positions for cushion
adjusting screws will be 2 and 6 and the
standard positions for cushion checks
will be 4 and 8. With some mounting
styles, it is not possible to so locate the
adjusting screws and checks. For
example, a Trunnion Front Mount has
the trunnion pins located in positions 2
and 4 on the head. With the port in
position 1, the only side available for
both adjusting screw and check is
position 3. Since both will then be
located on the same side, they will be
located off-center. This example would
hold true with the TR, CL, FHF and
RHF mounts. See
Chart A for standard
positions that will be supplied unless
otherwise specified. When requested,
other positions can be supplied so
long as there is no interference with
mounting.
Where access to an adjusting screw or
check could be made difficult because
of proximity to a mount, the locations
of the screws will be slightly off-center.
An example of this would be a small
bore cylinder with a side lug mount.
Because of space limitations, neither
cushion adjusting screws nor cushion
ball checks can be put into 1
1 / 2 ", 2" and
2 1 / 2 " bore sizes for cushioned front
when they are specified with 2:1 rod
diameters.
Special Variations
The Sheffer Corporation manufactures
many cylinders with variations to meet
customer special needs. Some of the
most popular variations are:
• Cylinders with Boots
• Combination Mount Cylinders
• Precision Stroke Cylinders
• Tandem and Multi-stage
Cylinders
• Adjustable Stroke Cylinders
• Non-rotating Rod Cylinders
• Cylinders with Stainless Steel
Piston Rods
• Cylinders for Underwater
Service
• Many More
Please request a quotation for any
special requirement.
Position Diagram for Ports,
Air Bleeds, Cushion Adjusting
Screws and Cushion Checks
1
2
3
4
5
6
7
8
Cushions, Porting and Air Bleeds
CUSHION
ADJUSTING CUSHION
MOUNT SCREW CHECK
TF AND FHF 3 AND 6 3 AND 8
CL 3 AND 7 3 AND 7
TR AND RHF 2 AND 7 4 AND 7
ALL OTHER
MOUNTS 2 AND 6 4 AND 8
Chart A
Standard Positions for Cushion Adjusting Screws and Cushion
Checks in Relation to Port Positions by Style of Mounting.
1 MH-6