12 inch

Triple-Sheave-J-Block

Key to three sheave J-Block Model Numbers

J 10 T 10 B T A
Shorty “J” Crane Block Safe Working Limit-Tons

Number of Sheaves

T=3
Triple

Sheave Size – Nom. O.D.

Sheave Bearing:

B = Bronze Bushed
R= Roller Bearing

Hook-Thrust Bearing

Cheek Weights:
A = No wts.
AB = Med. wts.
B = Std. wts.
C = X-Heavy wts.


Model WT. A B E F H J K
    Overall Net Thick- Width Throat-Opening Hook Hook
 
 
Length
Length
ness
 
w/ Latch
Thick.
Width
J-15T12BTA 200 27.375 24.750 8.375 16 1.91 2.53 1.93
J-15T12BTB 325 27.375 24.750 12 16 1.91 2.53 1.93
J-15T12BTC 475 27.375 24.750 16.500 16 1.91 2.53 1.93
J-15T12RTA 200 27.375 24.750 8.375 16 1.91 2.53 1.93
J-15T12RTB 325 27.375 24.750 12 16 1.91 2.53 1.93
J-15T12RTC 475 27.375 24.750 16.500 16 1.91 2.53 1.93
J-20T12BTA 255 9.750 26.750 8.875 16 2.80 3.00 2.38
J-20T12BTB 380 29.750 26.750 12.500 16 2.80 3.00 2.38
J-20T12BTC 530 29.750 26.750 17 16 2.80

3.00

2.38
J-20T12RTA 255 29.750 26.750 8.875 16 2.80 3.00 2.38
J-20T12RTB 380 29.750 26.750 12.500 16 2.80 3.00 2.38
J-20T12RTC 530 29.750 26.750 17 16 2.80 3.00 2.38
J-25T12BTA 255 29.750 26.750 8.875 16 2.80 3.00 2.38
J-25T12BTB 380 29.750 26.750 12.500 16 2.80 3.00 2.38
J-25T12BTC 530 29.750 26.750 17 16 2.80 3.00 2.38
J-25T12RTA 255 29.750 26.750 8.875 16 2.80 3.00 2.38
J-25T12RTB 380 29.750 26.750 12.500 16 2.80 3.00 2.38
J-25T12RTC 530 29.750 26.750 17 16 2.80 3.00 2.38
J-30T12BTA 305 35 31.250 9 16 3.28 3.50 3.00
J-30T12BTB 425 35 31.250 12.500 16 3.28 3.50 3.00
J-30T12BTC 575 35 31.250 17 16 3.28 3.50 3.00
J-30T12RTA 305 35 31.250 9 16 3.28 3.50 3.00
J-30T12RTB 425 35 31.250 12.500 16 3.28 3.50 3.00
J-30T12RTC 575 35 31.250 17 16 3.28 3.50 3.00


Dead End Chart

Wire Rope Size T U For Pin Size
7/16″ thru 5/8″ 1 1.28 1-1/4
3/4″ thru 1″ 1.25 1.65 1-5/8
1-1/8″ thru 1-3/8″ 1.75 2.51 2-1/2

*Gunnebo Johnson Design Factor is 4 to 1, with some exceptions;

45 Ton models 3.6 to 1

60 Ton models 3.7 to 1

325 Ton models 3.7 to 1