Dover OPW 891 Series User manual

891 Series Loading-Arm Counterbalance
The 891 Series Hi-Load Counterbalance represents the
best available technology in loading-arm counterbalancing.
Today’s applications demand higher spring loads to
accommodate longer reaches and additional equipment
that is commonly specified on loading arms. The 891 delivers
by providing roughly 50% more spring capacity than our
previous counterbalance model.
Benefits
• Easy, Precise Adjustment – A simple turn of the adjustment
bolt provides finite adjustment to tune your loading arm to
the desired balance point.
• No Special Tools Required – Standard socket wrench
• Wide Range of Motion – 80° of motion
(55° up and 25° down)
• Stable Balancing – Through the entire range of motion
• Integral Upward & Downward Travel Stops –
Fully adjustable to limit the range to your application
• Safe, Robust Design – Tested under full-load conditions
for more than 100,000 cycles with no degradation in
performance
Specifications
• Type – Right-Hand/Left-Hand Hi-Load Loading Arm Counterbalance
• Working Temperature Range – -50° F to +176° F
(-46° C to +80° C)
Selection Guide
ENGINEERING
891 D - 48RH - LT
891 = Series D= 13–16K
E= 16–19K
Swivel
Size
3= 3"
4= 4"
6= 6"
Swivel
Series
3= 3000
8= 8000
Low
Temperature
RH = Right-Handed
LH = Left-Handed
IMPORTANT: OPW products should be used in compliance
with applicable federal, state, provincial, and local laws and
regulations. Product selection should be based on physical
specifications and limitations and compatibility with the
environment and materials to be handled. OPW MAKES
NO WARRANTY OF FITNESS FOR A PARTICULAR USE.
All illustrations and specifications in this literature are based
on the latest product information available at the time of
publication. OPW reserves the right to make changes at any
time in prices, materials, specifications and models, and to
discontinue models without notice or obligation.
opw-es.com
891 Series
Counterbalance

IMPORTANT: OPW products should be used in compliance with applicable federal, state, provincial, and local laws and regulations. Product selection should be
based on physical specifications and limitations and compatibility with the environment and materials to be handled. OPW MAKES NO WARRANTY OF FITNESS
FOR A PARTICULAR USE. All illustrations and specifications in this literature are based on the latest product information available at the time of publication. OPW
reserves the right to make changes at any time in prices, materials, specifications and models and to discontinue models without notice or obligation.
891 Series Loading-Arm Counterbalance
# Qty Description 890D-48RH 890D-48LH 890E-48RH 890E-48LH
1 1 Bolt, Adjustment, 890 HLTS, SST C-21557-M C-21557-M C-21557-M C-21557-M
2 1 Nut, Barrel, 890 HLTS, SST C-21399-M C-21399-M C-21399-M C-21399-M
3 1 End Cap, 890 HLTS, DI C-21401-DI C-21401-DI C-21401-DI C-21401-DI
4 1 Housing Assy, 890 HLTS, Lo-Temp CST/SST, RH, 4" C-22633 C-22792 C-22633 C-22792
5 1 Shaft, 890 HLTS, SST C-21558-M C-21558-M C-21558-M C-21558-M
6 1 Spring Arm, 890 HLTS, RH, DI C-21404-DI C-21496-DI C-21404-DI C-21496-DI
7 1 Bushing, Spring Arm, 890 HLTS, BRZ C-21405-M C-21405-M C-21405-M C-21405-M
8 1 Torsion Spring
(Spring Coil Color)
C-21465-M
(White)
C-21466-M
(Black)
C-21406-M
(Blue)
C-21407-M
(Green)
9 1 Nameplate, 890 HLTS, Alum C-21495-M C-21495-M C-21495-M C-21495-M
10 1 Link Arm, DI E-20041-DI E-20041-DI E-20041-DI E-20041-DI
11 4 Screw, Hex Cap, CST, ZP, 5⁄8"-11 x 1-1⁄4" H-33183-M H-33183-M H-33183-M H-33183-M
12 2 Grease Fitting, SST, 1⁄4-28 H-06713-M H-06713-M H-06713-M H-06713-M
13 4 Retaining Ring, CST, 5⁄8" H-30321-M H-30321-M H-30321-M H-30321-M
14 4 Washer, Flat H-30361-M H-30361-M H-30361-M H-30361-M
15 1 Nut, Hex, SST, 5⁄8"-18" H-32931-M H-32931-M H-32931-M H-32931-M
16 2 Pin, Linch, CST ZP, 1-4" H-32281-M H-32281-M H-32281-M H-32281-M
17 1 Washer, Flat, CP/ZP, 1" H-32280-M H-32280-M H-32280-M H-32280-M
18 1 Washer, Spherical, CST ZP, 7⁄8" H-32393-M H-32393-M H-32393-M H-32393-M
19 2 Pin, Link Arm, Greasable, SST, 5⁄8" H-32394-M H-32394-M H-32394-M H-32394-M
20 2 Bumper Stop, 890 HLTS, CST H-32421-M H-32421-M H-32421-M H-32421-M
21 8 Screw, Cap, Socket Head, ZP, 5⁄16"-18 H-31278-M H-31278-M H-31278-M H-31278-M
22 8 Washer, Lock, ZP, 21⁄64" H-03563-M H-03563-M H-03563-M H-03563-M
23 4 Drive Screw, Type U, #10 X 3⁄8" H-30741-M H-30741-M H-30741-M H-30741-M
• Note: 890D, Right-Handed Spring Assembly Shown.
Some part numbers would vary for other spring sizes and orientations.
Consult factory for assistance.

891 Series Loading-Arm Counterbalance
ENGINEERING
opw-es.com
Upward/Downward Travel Stops
Adjustment
The 891 is equipped with integral upward and downward
travel stops. This allows you to limit the travel of your
loading arm to avoid obstructions that may be at your site
(e.g., overhead lighting or pipe racks).
Adjustment is very simple:
Position bumper stop(s) in the desired positions and secure
with four (4) supplied cap screws and lock washers.
When to Adjust
• To raise loading arm higher or for more lifting action
INCREASE torque
• To decrease loading arm vertical travel or to slow the rate
at which the arm rises, DECREASE torque
Note: Prior to any adjustment, loading arm should be raised
and secured in highest possible position (preferrably 45°).
• Place 1-1⁄16" socket wrench on ADJUSTMENT BOLT
• To INCREASE torque rotate ADJUSTMENT BOLT clockwise
• To DECREASE torque rotate the ADJUSTMENT BOLT
counter-clockwise
• Release wrench and test loading-arm lifting action
Note: Prior to any loading-arm disassembly, spring tension
should be completely relieved.
Note: Right-hand spring balance shown.
Torque:
For more lifting action INCREASE torque.
For less lifting action DECREASE torque.
IMPORTANT:
A minimum clearance of
approximately 17" is required
for the spring balance to
clear any obstruction.

IMPORTANT: OPW products should be used in compliance with applicable federal, state, provincial, and local laws and regulations. Product selection should be
based on physical specifications and limitations and compatibility with the environment and materials to be handled. OPW MAKES NO WARRANTY OF FITNESS FOR
A PARTICULAR USE. All illustrations and specifications in this literature are based on the latest product information available at the time of publication. OPW reserves
the right to make changes at any time in prices, materials, specifications and models and to discontinue models without notice or obligation.
891 Series Loading-Arm Counterbalance
Maintenance Safety
Lubrication
Pins [22] should be lubricated on an annual basis.
Any bearing gel that meets local conditions is acceptable.
Shaft [5] should be lubricated on an annual basis.
1. Raise loading arm to highest position to unload spring.
Secure arm.
2. Mark end cap [3] position, and loosen adjustment bolt [1].
Adjustment bolt should move easily with spring unloaded.
3. Remove pin [19] and washer [18] from end cap side of shaft.
4. Move shaft [5] two inches from housing and cover extended
shaft with grease. (Recommend using heavy bearing grease,
such as Royal Purple or Thermasil T-100)
5. Complete maintenance in reverse order.
Note: Consider using an OPW Lock Down Unit with
the 891 Spring.
1. While installing and using the Loading Arm, always
wear adequate personal protection, including hard hats,
gloves and steel-toed work boots. Failure to wear
adequate personal protection may cause serious personal
injury and death.
2. Always follow the procedures prescribed in this
document. Failing to follow the procedures prescribed
may damage the Loading Arm and cause serious personal
injury and death. Consult Loading Arm Installation,
Maintenance & Safety Manual for more details.
DANGER: Before performing any maintenance, always
secure the Loading Arm and remove all tension from the
counterbalance and torsion spring. The Loading Arm
counterbalance spring contains a substantial amount of
stored energy. You must relieve this energy before any
disassembly. Failure to remove all tension from the
counterbalance spring of the Loading Arm before
maintenance may cause serious personal injury or death.
Failure to follow these warnings
could result in serious personal injury,
property damage or product failure.
WARNING
opw-es.com
ES-LDS • 08/22 • 1K
NOTE: All information subject to engineering and/or other changes. All trade names are copyrighted. Patents Pending. ©2022 OPW Engineered Systems.
©2022 Delaware Capital Formation, Inc. All Rights Reserved. DOVER and the DOVER logo are registered trademarks of Delaware Capital Formation, Inc.,
a wholly-owned subsidiary of Dover Corporation.
www.opw-es.com •9393 Princeton-Glendale Road •Hamilton, Ohio, USA 45011, USA
Phone:[phone] •Phone: [phone] •Fax:[phone]