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

268
the dog locking latch (upper door) is the interlock
system described in paragraph 32.
(b) Control lever. - The control lever is bracket
mounted adjacent to the starting lever. It is
interlocked as described in paragraphs 30 and
31 and is arranged with a quadrant designating
three position movement:- to "Ho i st ,IIto IILower,1f
and "Stop.1f It is keyed to shafting and
levers extending forward to the A-end tilting
plate controls and to the B-end control cams.
(C) Selector control lever. - This hand lever is
located below the starting and control levers.
It is arranged so that it can be positively
held (by pin) in either of its selective positions.
(Designated, "Se r-vo Electrical!! and
IIServo Mechanical and Manual.!!) The shaft to
which it is keyed extends forward to the hoist
.machine and is provided with lever linkage connected
to a brake release valve, a venting valve
and a control lever shaft latch.
Through these control levers and other arrangements in the
A-end, the hoist has three selective types of control. These
are designated, "Se r-vo Electrical," "Ser-vo Mechant caLt' and
"Manual. it The first and second control the A-end displacement
through power operation (servo pressure) of the pump yoke.
The third method is without control pump pressure and manually
posi tions the pump yoke. All methods are described in the circuit
descriptions, paragraphs 49 to 69. Manual control is an
emergency selection. It should not be used for extended periods,
and then only at reduced speed, because of operating
limitations as explained in paragraphs 64, 65 and 75.
ELECTRICHYDRAULICDRIVE
34 . Each hoist machine is an electric hydraulic drive
which includes the following principal parts.
Electric motor
Hydraulic pump (A-end)
A-end valve block assembly
Hydraulic pump, auxiliary
Hydraulic motor (B-end)
Hoist drum
Drum brake assembly
Limit stop cam mechanism
Latch and vent valve
Safety latch operating cylinder
Limit switch assembly