Duff-Norton Machine Screw Rotating 500lb - 1 Ton - Manual (Page 5)

5
1-5. Important Precautions
To ensure that Duff-Norton actuators provide reliable
service over a period of years, the following precautions
should be taken:
1. Select an actuator that has a load rating greater than
the maximum load that may be imposed upon it.
2. The structure on which the actuators are mounted
should have ample strength to carry the maximum
load, and should be rigid enough to prevent undue
deflection or distortion of the actuator supporting
members.
3. It is essential that the actuators be carefully aligned
during installation so that the lifting screws are
perfectly plumb and the connecting shafts are exactly
in line with the worm shafts. After the actuators,
shafting, gear boxes, etc., are coupled together, it
should be possible to turn the main drive shaft by
hand. If there are no signs of binding or misalign-
ment, the actuator system is then ready for normal
operation.
4. Actuators should have a greater raise than is needed
in the actual installation. Should it be necessary to
operate these actuators at the extreme limits of
travel, it should be done cautiously.
1-4 Dimensions (Cont.)
Note: Housing Dimensions and Base Configurations Vary.
Caution
Do not allow actuator travel to go beyond catalog
closed height (A), or serious damage to lifting nut
or the internal actuator mechanism may result.
Refer to tables of specifications (par. 1-4) for
closed height (A) of respective units.
5. The worm shaft speed should not exceed 900 RPM
for heavy loads or 1800 RPM for light loads of one-
fourth (or less) of the actuator load rating for 500 and
1000 pound rated units. For units with a one-ton load
rating, worm shaft speed should not exceed 1800
RPM.
6. The lifting screw should not be permitted to accumu-
late dust and grit on the threads. If possible, screws
Table 3. Inverted Models
Note: Dimensions are subject to change wwithout notice.
Model A B C D F G H I J K
N u m b e r Rating ( i n ) ( i n ) ( i n ) ( i n ) ( i n ) ( i n ) ( i n ) ( i n ) ( i n ) ( i n )
D M - 2 5 5 6 1/4 TON Raise + 1 1/2 5 / 8 2 3/8 3 / 8 0 . 3 1 2 7 / 8 3 / 8 2 1/4 4 Holes- 9/32 Dia. on 1 3/4 Dia. B.C. 1
D M - 2 6 2 6 1/2 TON Raise + 1 7/8 5 / 8 2 3/8 3 / 8 0 . 4 3 7 7 / 8 3 / 8 2 1/4 4 Holes- 9/32 Dia. on 1 3/4 Dia. B.C. 1
D M - 2 5 0 2 1 TON Raise + 1 3/4 5 / 8 3 1/4 1 / 4 0 . 5 0 0 1 1/2 1 / 2 3 1/4 4 Holes- 13/32 Dia. on 2 3/8 Dia. B.C. 1 1/2