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Rocker Restoring Soring
Impression Control Lever
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Light Stud is Shown in Medium Position
Figure 4-58.
To prevent smearing and alignment problems, long carriage machines are equipped with a carrier support to prevent flexing of the print shaft. The support is mounted to the power frame just below the front of the carrier. The bottom of the carrier pad serves as a buffer. (Figure 4-59)
Carrier Pad
Figure 4-59
The quality of typed impression is determined toa large extent by the condition of the platen.
Ple1ten rubber may be adversely affected by numer-ous factors such as light, heat, chemicals, etc.
An old or worn platen may be considerably harder than a new platen and may also vary slightly in diameter. The machine is equipped with a platen
with-a hardness density comparable to the number
2platen used with the standard
I BMElectric Type-writer. (Figure
4-60)The platen is held in position in the machine by a latch pivoted at the front of each carriage end plate. The platen may be removed by pressing the rear of the latches down and lifting the platen out.
It may be re-installed by snapping it into position without depressing the latches, however, care must be taken to prevent bending the platen shaft.
Also, releasing feed roll tension will aid in re-in-stallation of the platen.
Copy Control Lever
Platen Adiusting Plate
Figure 4-60.
The copy control mechanism positions the
platen front to rear for different thicknesses of
typing material. The copy control mechanism is
operated by a lever located at the left end of the
carriage. The lever is attached to a shaft that
extends through the sides of the powerframe. An
eccentric collar attached to each end of the shaft
operates between adjusting plates attached to the
carriage end plate. As the lever is moved to the
rear, the shaft rotates causing the eccentric collars
to force the carriage plates to the rear. The platen
and entire paper feed mechanism move with the
carriage plates. When the· copy control lever is
pulled forward, the eccentric collars contact the
platen adjusting plates and force the carriage
for-ward into the normal position. The copy .control
lever can be set in five different positions. A
spring detent attached to the power frame acts
against a knob on the copy control lever to hold
it in place. (Figure
4-60)HCS-220003 Section IV 4-9. PAPER FEED
In this section we will discuss how the paper is held firmly against the platen, both vertically and horizontally, and how the paper is indexed verti-cally. First, let's look at the paper feed mechanism~
The paper feed operated by pressing the paper tightly against the platen so that it must move as the platen rotates. The paper is held against the platen by the front ana rear reed roll assemblies located beneath the platen. Each feed roll assembly contains three or four rubber rollers equally spaced along the feed roll shaft and molded to the shaft. (Figure 4-61)
The feed rolls mount in the front and rear feed roll arm assemblies. The front feed roll arms pivot on the feed roll actuating shaft. Also pivoting on the feed roll actuating shaft is
a
feed roll arm. There are several holes in the upper extension of the feed roll arm. Heavy extension springs are connected between the carriage tie rod and one of the holes to provide a means of adjust-ing the feed roll pressure.The paper deflector guides the paper around the platen. It is supported beneath the platen by lugs on the front and rear feed roll arms. A lug at each end of the deflector fits over a stud on the paper feed mounting arm to maintain the correct position of the deflector. (Figure 4-62)
Index Lever Rear Feed Roll Arm
Index Selector Cam
Feed Roll Release Lever
Carriage Tie Rod
Tension Spring
Deflector
Overthrow Stop
Feed Rolls
Feed Roll Arm
Figure 4-61.
4-23
Section IV HCS-220003
Deflector
Positioning Stud
Figure 4-62.
As the paper is inserted into the machine, an adjustable guide, mounted on the case at the rear of the platen, serves to position the paper for its left margin positon. The paper deflector guides the paper between the rear feed roll and t)1e platen.
As the platen is turned, the paper is forced to move with the platen. The deflector guides the paper around the platen into positon between the front feed roll and the platen. As the paper is fed farther, the end of the paper is guided upward by the cardholder attached to the rear of the carrier.
(Figure 4-63)
The cardholder assists in holding the typing material against the platen in the printing area.
A scale on each side of the cardholder aids the typist in re-inserting material into the machine to a specific printing point. The vertical marks on the scale indicate the middle of the character space and horizontal line indicates the bottom of the writing line. A single mark, located at the top of the cardholder, indicates the middle of the next character to be typed.
Above the writing line, the paper is engaged by two rubber rollers mounted on the paper bail.
These rollers hold the paper against the platen above the writing line to reduce the possibility of over printing on the paper. The rollers are also
used to feed the paper vertically after the bottom of the paper has left the front feed rolls.
The paper bail is supported by a lever at each end and pivots front-to-rear. A hair pin spring attached to each bail lever, serves as a toggle to hold the bail rolls either to the rear against the platen or forward in the release position.
The pressure of the feed rolls is released from the platen to allow the operator to position the paper more accurately and to allow easier insertion
and removal of the paper. Paper release is accom-plished by pulling forward on the paper release lever located at the right end of the machine. The feed roll release levers are clamped to the feed roll actuating shaft and rest behind a lug of each front feed roll arm. As the shaft rotates, the feed roll release levers rotate the front feed roll arms down, away from the platen. Due to the inter-connection between the front feed roll arm and the rear feed rol 1 arm, the rear feed roll arms are forced away from the platen. When the paper release lever has been pulled all the way forward, the end of the feed roll release arm detents to hold the feed roll release lever in the released position. (Figure 4-64)
Bail Rolls
Card Holder Paper Bail Lever
Guide
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Deflector Support Lugs
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Deflector
Hairpin Spring
Figure 4-63.
Paper Feed Braces
Feed Roll Release Arm Lever
Figure 4-64.
HCS-220003 Section
IV
4-10. ESCAPEMENTEscapement is the controlled single space movement of the carrier to the right that occurs every time a character is printed. The carrier is under a constant spring tension to the right. The escapement mechanism allows or prevents the carrier's movement to the right under this spring tension.
At rest, a pawl which is mounted to the carrier engages a fixed escapement rack and pre-vents the spring tension exerted by the mainspring from pulling the carrier to the right. During an escapement operation, the pawl is temporarily
·removed from the rack. (Figure 4-65)
Backspace Rack
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Trip Link
Escapement Cam
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There are two pawls mounted to the carrier, an escapement pawl and a backspace pawl. There are also two racks, an escapement rack and a back-space rack.
An escapement operation is obtained by forc-ing the escapement pawl to the rear out of engage-ment with the rack teeth. Due to the slotted mounting hole, as soon as the pawl clears the escapement rack tooth it is snapped to the right by the pawl spring. The escapement pawl is allowed to move to the front into engagement with the next tooth. The carrier then moves to the right until it comes to rest against the escapement pawl.
Escapement Rack /
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Escapement PawlTrigger Lever
Figure