OP-755 Part 2 Pages 197-401 - Personal Page of GENE SLOVER

246
32. The hydraulic arrangement of these elements is shown
on the diagrams of figures 45 to 48, inclusive. Valve IICIIis
the direction control valve. It is manually positioned from
IIHoistll to IILowerllin order to set the pawl mechanisms to opera
te for the reverse cycle. When in either position it is
locked by a solenoid plunger which is energized by either of
two switches. These are located at the two hoist controls and
function to interlock lever IICIIwhenever the control is moved
from neutral. (See drs. no. 234274 and 234275 and par. 38.)
33. Operating valve IIKIIis arranged to be actuated by
movement of the rack (when lever "ell is in lowering position
only). (See fig. 48.) This is accomplished by a cam surface
(fig. 43) on a rack connecting bar (located immediately above
the upper intermediate rack pawl). This cam surface contacts
and lifts a roller and cam lever in the final four inches of
upward rack mov.ement. At that position the rack pawls are
projecting to lift projectiles supported on the tube pawls and
as the load is relieved from the latter, valve IIKIIis moved
(by the cam lever), pressure is ported to the tube pawl operatingcylinder,
and those pawls are retracted to permit the descending
projectiles to pass. Each tube pawl moves back into
the hoistway as the passing projectile is lowered and thus is
positioned (by spring) to receive the proj ectile from the stage
above. At the bottom of the stroke the tripping cams retract
the rack pawls as the load is again taken by the tube pawls.
Hoist e6ntrols, Interlocks and Indicators
34. Thehoist controls, interlocks and indicator devices
include the arrangements described in the cradle assembly text,
paragraphs 20-c, 20-d, the cradle operating control, paragraphs
25-' 26, the pawl control devices, paragraphs 27-31, and the
main circuit hoist controls and signal devices described below.
35. The main hoist control comprises dupl Lcat e installations
of control handles with their respective mechanical
interlock, eiectrical interlock and audi-ble and visual signals.
The control stations are adjacent to the hoist loading apertures
on the upper and lower projectile handling flats. Typical
arrangements are as shown on drawings number 234278 and
234279.
36. Control handle station. - The control handles are
mounted on shaft brackets which also function as mountings for
the interlock and indicator devices and for the vertical control
shaft that extends upward to the A-end. Tilting box angleof-tilt
adjustments are obtained through bevel gear and spur
gear train (dr. no. 234276) from the control shaft with shaft
rota tion and equivalent til t as indicated in the following
description of control handle limits of movement.