S&C Instruction Sheet 761-505
23
Installation
(e) With the operating handle as far as it will go in
the opening direction, each switch operat ing
lever should lie snugly against its open bumper.
See Figure 29. There should be perceptible
tension in the operating pipe, locking the switch
open. In the unlikely event these conditions are
not met, more switch blade travel is required.
Move the operating handle to its mid-posi tion
to take the strain off the operating-pipe linkage
and loosen the two bolts that clamp the adjust-
able lever arm of the bell-crank.
●
See Figure 30.
Shorten the adjustable lever arm one step
(
⅛
-inch (3 mm)) and retighten the bolts. Shorten-
ing the adjustable lever arm increases switch-
blade travel. Then, readjust for full operating
handle travel as described on page 18.
(f) Repeat this procedure—shortening the
adjustable lever arm of the bell-crank in one-step
increments and readjusting for full oper ating
handle travel—until full switch-blade travel is
attained.
Figure 29. Verifying the switch operating lever is against its
open bumper.
Open bumper
Adjustable lever arm
Figure 30. Shortening the adjustable lever arm of the bell-crank.
●
For the tiered-outboard switch configuration, a bell-crank is not used.
Adjust switch travel at the upper (adjust able) rod guide. Lengthen the
driven arm to increase switch travel; shorten the driven arm to decrease
switch travel. Then, readjust for full operating handle and switch-blade
travel as described in the "Checking Alignment" section on page 18.
