Operation of Recorder Pen

TM 11-6660-204-25

wise direction. This knob is connected to the chart

of gears is used to prevent any backlash between

roller shaft by a set of beveled gears with a ratio

the balancing motor and recorder pen.

(2) The plunger of pen-lifting solenoid L501

of 2 to 1 (figs. 219 and 220).

is connected to the pen-carriage shaft through me-

(6) Three chart guide rods are used in the

chanical parts as shown in figure 2-21. When the

frequency-time recorder, but only two are mova-

solenoid is deenergized, pressure exerted by

ble. The movable intermediate guide rod on the

spring O576 pushes the double-ended bolt against

underside of the frequency-time recorder (fig.

the pen-lifter bracket which rotates the pen-car-

2-19) has a lever mounted on the left side of the

riage shaft slightly, and therby lifts the pen from

rod. When the rod is in its open position (to the

the chart. When the solenoid is energized, the dou-

rear), the lever holds the pen-lifting linkage and

ble-ended bolt is pulled toward the solenoid, The

does not permit the pen-lifting solenoid to lower

pen-pressure nuts then push against the pen-pres-

the recorder pen. The front chart guide rod can be

sure spring which pushes the pen-lifter bracket,

pulled out approximately 1 inch to insert the

The pen-lifter bracket rotates the pen-carriage

chart. The rear chart guide rod is located approxi-

shaft and pushes the pen against the chart roller.

mately halfway between the supply roll and the

The pressure with which the pen is held against

intermediate chart guide rod.

the chart is adjusted by a pen-pressure set nut

and held in place by a locknut.

b. Operation of Recorder Pen,

(3) The pen heater is thermostatically con-

trolled and mounted around the pen barrel (ink

(1) The recorder pen (fig. 2-20) is a ball-

chamber), The heater is operated from 6.3-volt ac

point pen which rides on its carriage above the

source which is supplied through thermostatic

chart roller, The carriage is moved along the pen-

switch S501 and a set of contact bars that run

carriage shaft by the pen-carriage cable which is

parallel and above the carriage shaft. The voltage

connected to a pen-carriage cable drive pulley

is applied from the contact bars to a set of sliding

through two sets of guide pulleys, one at each end

contacts which are connected" to pen heater

of the frequency-time recorder casting, The pulley

HR501. The `thermostatic switch operates the

is attached to the split-gear assembly, which is

heater at temperatures below approximately 0C

driven by balancing motor B501 through a reduc-

(32F. ) Panel lamps 1501 through 1504 are

tion gear assembly. The split-gear assembly con-

lighted by the same 6.3-volt source and provide

sists of two identical gears (sometimes called scis-

sor gears ) that are spring-loaded. The double set

illumination for the recorder scale and chart.

Figure

2-20.

Frequency-time

recorder,

front

view.

2-24