Couplings

Couplings
TYPE SN ADJUSTABLE
REX ® THOMAS ® COUPLINGS
Type SN adjustable couplings were developed as emergency replacements for standard Type SN couplings and are available from stock in
most sizes required for cooling tower applications. Each shaft may be adjusted thru a four-inch length range, using a special compression
bushing to lock the shaft in place once the length is set.
A G
B
N
L
N
General
Dimensions (inch) &
Engineering Data
Weight
WR
2
Change
Change
➀
➁ Per Inch of ➁ per inch of Axial
Coupling
Min. Adjustment W eight
“ L” WR
2
“L” Capacity
Size
Max
Bore
A B G H “L” Range ( lb. ) ( lb. ) ( lb.-in.
) ( lb.-in.
) (in.)
162
1.88
4.47
1.88
2.75
0.54
14.25
4.00
19
0.13
37
0.22
± 0.036
200
2.25
5.44
2.12
3.28
0.57
15.12
4.00
30
0.29
80
0.56
± 0.036
226
2.62
5.81
2.62
3.78
0.58
17.28
4.00
43
0.33
151
0.82
± 0.036
262
3.12
6.69
3.00
4.50
0.47
18.88
4.00
61
0.41
253
1.60
± 0.043
➀ All Thomas disc couplings meet NEMA frame sleeve bearing motor specifications without modification or the addition of end-float restricting devices .
➁ Weight
and WR2 at maximum bore.
Note: See page 27 for selection data.
REX ® THOMAS ® BACKSTOP
W
CW - OPERATION ➁
CCW - BACKSTOP
A
MATE-UP ➀
BOLTING SUPPLIED
WITH BACKSTOP
ASSEMBLY
• Bolts Directly to Thomas SN & TSN-
CT Hubs
• Prevents reverse shaft rotation of
Cooling Tower Fans
• All Stainless Steel Construction
• Available from Stock
• For non-Corrosive environments
this can be supplied in carbon steel.
MAX.
BORE
OD
COMPRESSED
PAWL DIAMETER
(RUNNING)
SPRUNG
PAWL DIAMETER
(NO OPERATION)
SECTION A-A
A
B.C.
DIAMETER
Bolt-On Backstop Tabulation (inch)
Mating Hub bckstop Bolting Info
Pawl
Dia. (Ref) Compressed
Coupling
Size
Max Bore
B.C.
Dia. Capscrew Size
Min
Tap
DP
Tight Torque
( lb.-in.) O D W (Ref)
Compressed
Sprung
Speed
(RPM Ref)
162
1.88
2.312
1/4 - 20 NC × 1.50
0.62
25
200
2.12
2.688
1/4 - 20 NC × 1.50
0.62
25
5.25
1.00
5.69
6.50
450 RPM Ref
226
2.62
3.250
1/4 - 20 NC × 1.50
0.62
40
262
3.12
3.875
3/8 - 16 NC × 1.75
0.88
142
312
3.62
4.438
7/16 - 14 NX × 2.00
1.12
225
9.12
1.12
9.19
10.56
400 RPM Ref
350/375
4.00
4.875
1/2 - 13 NC × 2.00
1.12
350
Special
integral hub/backstop can be supplied.
➀ 162 & 200 size supplied with (4) socket head capscrews. All other sizes supplied with (4) hex head capscrews .
➁ Backstop may be inversely mounted for opposite rotation .
Note: Dimensions subject to change. Certified dimensions of ordered material furnished on request. 39