Ibm Selectric i/o Manual

Selectric

I/O

®

Keyboard Printer

Customer Engineering

Manual

of

Instruction

Issued to:

__________________

_

Branch

Office:

________________

_

Department:

________________

_

Address:

__________________

_

If

this

manual

is

mislaid,

please

return

it

to

the

above

address.

PREFACE

This manual has

been

written

to

include

the

maximum hardware or mechanisms

that

can

be

incorporated

in

the

"Selectric"

I/O

Keyboard

Printer

thru

October

1964.

The

particular

model you

are

concerned

with may not use

all

of

the

mechanisms

de-

scribed.

This manual covers models

731, 735, 765, 775,

1415,

1014,

Sabre,

Stretch,

7040/44,

1

620

Mod.

I\,

All rights

to

reproduce

this

material

are

reserved

by

IBM.

Address comments

regarding

the

comments

of

this publi

cation

to:

IBM

Office

Products Divi"sion,

Lexington,

Kentucky

40507

CONTENTS

Motor

and

Drive

...............................................................

1

Typehead

.............................

"

.......................................

3

Tilt

Mechanism

................................................................

5

Rotate

Mechanism

..............................................................

8

Keyboard

Section

and

Character

Selection

.........................................

12

Print

Selection

Unit

.....................

"

......................................

16

Selection

Contact

Assembly

.....................................................

18

Keyboard

Lock

.........................

"

......................................

20

Shift

.................................

"

......................................

22

Cycle Clutch

Operation

.........................................................

28

Alignment

...........................

','

......................................

29

Print

Mechanism

(Early

Style)

........

:

...........................................

39

Print

Mechanism

(Late

Style)

....................................................

41

Print

Escapement

......................•.....................................

41.5

Mainspring

.....................................•.............................

44

Operational

Cams

and

Control

Mechanism

.........................................

45

Operational

Selection

Unit

..............

','

......................................

49

Operational

Contact

Assembly

(Late

Style)

...............•.......................

50.1

Spacebar.

..

.

........................

,

.......................................

51

Spacebar

Mechanism

(Print

Escapement)

..........................................

54

Backspace

...........................

'

.•.....................................

54.1

Carrier

Return

(Early

Style)

.....................................................

55

Carrier

Return

(Late

Style)

...............•.....................................

58.1

Indexing

.......................................•............................

59

Platen

Variabl.e

...............................................................

62

Tabulator

.............................

','

......................................

63

Margin

Control

................................................................

69

Paper

Feed

and

Release ME:tchanism

..............................................

73

Fabric Ribbon

(Early

Style)

.......................................................

75

Red Ribbon

Shift

...............................................................

79

Fabric Ribbon

(Late

Style).

"

.........................................

,

...........

80

(2) INDEX SELECTION

LEVER

(I)COpy CONTROL

LEVER

(3)

PAPER RELEASE LEVER

(4)

PAPER

BAIL LEVER

(8)

(7)

ON/OFF

SWITCH

TAB

SET/CLEAR

SELECTRIC

1/0

KEYBOARD

PRINTER

Operating

Controls

1.

Copy

Control

Lever -To

compensate

for

the

thickness

of

multiple

forms,

the

copy

control

lever

is

provided.

As

the

copy

control

lever

is

moved

to

the

rear,

the

platen

wi

II

move

farther

away

from

the

typehead.

2.

Index

Selection

Lever

-

You

may

control

the

indexing

(line

space

movement)

of

the

platen

b)/

setting

the

index

selection

lever

forward

for

single

space

and

back

for

double

space.

3.

Paper

Re

lease

Lever

-

Move

the

paper

release

lever

forward

to

position

or

re-

move

paper.

4.

Paper

Bai I

Lever

-Holds

the

paper

against

the

platen

to

prevent

buckl

ing.

Should

be

moved

forward

when

inserting

paper.

5.

Margin

Set

Leve~

-

Provides

the

operator

with

a

means

of

changing

the

margin

settings.

6.

I

ndex

Key -

Provides

vertical

indexing

of

the

paper

without

changing

the

posi-

tion

of

the

carrier

assembly.

7.

On-Off

Switch

-Turns

the

pri

nter

on

and

off.

8.

Tab

Set/C

lear

-,

Used

to

set

or c I

ear

tab

stops.

9.

Margin

Release

Key -

Provides

a

means

of

operating

the

printer

beyond

the

margin

settings

without

changing

the

settings.

MOTOR

AND

DRIVE

The motor used in

the

Selectric

I/O

Printer

is

a

three-inch

shaded

pole,

induction

type: motor

that

requires 115

volts,

60

cycles

A.

C.

(Fig.

1).

I~

is

rated

at

1/35

h

.p.

The motor

is

mounted

at

the

left

rear

corner

of

the

machine

with

the

pulley

toward

the

right.

It

is

attached

to

an

ad~ustable

bracket

at

each

end

by

ring

shaped

spring

retainers

that

en-

eirc

Ie

the

rubber motor mounts.

3"

Shaded Pole Motor

Motor

Pulley

and

Clutch

Mechanism

FIGURE

1.

Shaded Pole Motor

The motor may be removed easi

Iy

after

snapping

the

retainers

off

the

brackets.

With

the

belt

removed

the

right

end

of

the

motor may be moved

to

the

rear,

and

the

motor may be removed

toward

the

right.

With

this

bracket

design,

the

force

of

the

motor in

operation

is

against

the

bracket

rather

than

against

the

retaining

clips.

The motor bearings

are

babbit

inserts pressed

solidly

into

the

motor

end

bells.

Each

bearing

is

completedy surrounded by a

saturated

oil

wick.

Asmall square

wick

fits

into

a

notch

inthe

top

of

each

bearing

to

supply oil

directly

11'0

the

rotor

shaft.

1

It should seldom be necessary

to

disassemble

the

motor;

however,

care

should be

taken

in

replacing

either

end

bell

that

is

not

in-

vertedwhen

installed.

The oil hole in

the

left

end

bell

and

the

notch

in

the

bearing

would

then

be on

the

bottom.

The

starting

torque

for

the

motor

is

provided by

the

shaded

pole

principle.

No

capacitor

is

required.

The motor has

an

internal

circuit

breaker

to

prevent

damage

to

the

field

coil in

the

event

the

switch

is

left

ON

with

the

ma-

chine

stalled.

The

circuit

will

open

only

if

the

motor

is

allowed

to

remain

stalled

for a period

of

time;

therefore

there

is no

dangerof

an

open

circuit

during normal

operation.

The motor

will stall

only

in rare cases where a maladjustment

or

parts

breakage

causes

the

machine

to

lock.

After

the

motor has

re-

gained

normal

temperature,

the

circuit

breaker

wi

II

again

close

the

circuit.

The

circuit

breaker

will

continue

to

open

and

close

as long as

the

motor

is

stalled

and

the

switch

is

left

ON.

Because

of

its

design,

the

shaded pole motor tends

to

run

at

a

higher

temperature

than

other

IBM

typewriter

motors.

Core

should be

taken

in handling

the

motor

to

prevent

being

burned.

In

order

to

prevent

over-heating,

a cooling system is

incorpo-

rated

in

the

design

of

the

motor. A fan

attached

to

the

right

end

of

the

rotor pulls

air

through

the

left

end

bell

and

across

the

field coi Is. The

air

is

then

discharged through a

duct

at

the

right

rear

corner

of

the

motor. The

air

escapes

through a

grill in

the

rear

of

the

machine

cover.

The hot

air

being

dis-

charged

pulls cool

air

with it

from

within

the

machine.

The

air

that

ultimately

emerges

from

the

machine

is

cooled

to

near

room

temperature

so

that

no

objectionable

heat

results.

The

three

wire grounded system has

the

third line cord

lead

attached

to

the

powerframe

at

the

cord c

Ii

p

screw.

A short

jumper wire

is

connected

between

the

motor

and

powerframe

(Fig.

2).

White

Green

Solderless

Connector

Black

Plug

Switch

FIGURE

2.

Shaded Pole Motor Diagram

In

some

Selectric

I/O

Printers, a

capacitor-start

induction

type

motor is used

(Fig.

3).

A

capacitor,

in

the

starting

winding

circuit,

provides a starting torque for

the

motor

and

controls

the

direction

of

rotation.

The

capacitor

also

re-

mains in

the

circuit

whi

Ie

the

motor

is

running.

The

capaci-

tor

is

mounted in a vel:tical position by a

bracket

at

the

right

rear

corner

of

the

machine.

FIGURE

3.

Capacitor-Start

Motor

The

capacitor

start

three

wire

grounded

system has in

addi-

tion

to

the

three

wire

line

cord

and

jumper

wire

a

grounded

capacitor

mounting

bracket.

This

is

done

by

using

metal

mounting screws

(Fig.

4).

Green

-

Run

Motor

White

Green

Black

Plug Solderless

Connector

FIGURE

4.

Capacitor-Start

Motor Diagram

The switch

and

switch

lever

are

mounted

on

the

right side

of

the

keyboard.

The switch

lever

operates

the

electrical

switch

by means

of

a short Iink

extending

to

the

rear.

It

is

operated

by pressing down on

the

rear

of

the

lever

to

turn

the

machine

ON

and

the

front

to

turn

the

machine

OFF.

The switch

lever

is

labeled

ON

and

OFF.

When

the

switch

lever

is in

the

ON

position,

a

contrasting

color

at

the

front

of

the

switch

lever

shows just

above

the

case.

This

calls

attention

to

the

fact

that

the

machine

is

ON

to

minimize

chances

of

the

machine

being

left

running when

not

in

use.

In

addition

to

operating

the

typewriter

switch,

the

switch

lever

also

controls

the

keyboard

lockout

mechanism.

This mechanism

is discussed in

the

keyboard

section.

Motor

Contactor

(835 Printer)

Mounted

underneath

the

printer

near

the

shift

feedback

con-

tact

bracket

is

the motor

contactor

(Fig.

4.1).

The motor

con-

tactor

is

a 48V

relay

that

works in

conjunction

with

the

as-

sociated

electronics.

If

the

printer

ON/OFF

switch

is

in

the

ON

position

and

the

Communicate-Local

switch

is

in

Commu-

nicate,

the

printer

motor

can

be

turned

OFF

and

ON

by

the

motor

contactor

(Fig.

4.2).

Shield

Motor

Contactor

-lI....,r;•

...1~

Terminal

•

White

Green

Black

Plug

E

~

...

IIC Z \

..

".J

~

....

0 i z 2 3

$ z

~

I

:;

~

§ .. I

<

::i

FIGURE

4.1

Motor

Contactor

To

Power Supply

Grn

Wht

Blk

Motor

Contactor

• FIGURE

4.2

Motor Diagram

(835

Printer)

2

Shift

Contact

Actuating

Arm

Drive

An

eight-toothed

motor

pulley

provides positive drive for

the

operation

of

the

machine.

A

positive-drive

belt

transfers

the

rotation

of

the

motor

pulley

to

the

cycle

clutch

pulley

with a

speed reduction

of

3-5/8

to

1.

The shaded pole motor has less starting torque

than

the

cape-

ci

tor-start

motor •

To

insure

that

the

motor

wi

II

be a 1I0wed

to

start under a heavi

Iy

loaded conditi

on,

a

centrifuga

I

clutch

has been

incorporated

in

the

motor

pulley

design.

The motor

is

allowed

to

approach

normal operating

speed,

then

the,

clutch

engages

to

drive

the

machine.

The momentum

devel-

oped by

the

rotor causes

the

machine

to

start

even

though

several

mechanisms may have been tripped.

Capacitor

start

motors do not

require

a

centrifugal

clutch.

The motor

pulley

operates

freely on

the

end

of

the

rotor shaft

and

is

held in

place

bya grip ring

retainer.

Three

ratchet

teeth

extend

radially

from

the

left

end

of

the

pulley

(Fig.

5).

A

clutch

plate

hub assembly

is

set-screwed

to

the

rotor shaft just

to

the

left

of

the

motor

pulley.

Pivoted on

the

plate

are

two

clutch

pawls

(Fig.

5).

When

the

motor is

OFF,

the

pawls

are

spring loaded

against

stop lugs on

the

clutch

plate.

When

the

motor

is

turned

ON,

the

clutch

plate

turns with

the

rotor.

Centrifugal

force causes

the

clutch

pawls

tC)

pivot on

the

studs

of

the

cI

utch

plate

so

that

the

tip

of

one

of

the pawls

engages

a tooth

of

the

motor

pulley

(Fig.

5).

The

pulley

is

then

caused

to

rotate

and

drive

the

machine by means

of

the

cycle

clutch

pulley.

Motor Pulley

Clutch

Plate

Hub Assembly

FIGURE

5.

Motor Pulley

Clutch

The

cycle

clutch

pulley

is

mounted to a hub in

the

center

of

the

powerframe. The hub

is

supported by a porous bronze

bear-

ing and

is

in continuous rotation with

the

pulley

whenever

the

motor

is

runni

ng

.

On

eitherside

of

the

cycle

clutch

pulley

hub

is

a shaft

extend-

ing into

and

supported by

the

hub

(Fig.

6).

The shaft to

the

left

of

the

hub is

called

the

cycle

shaft.

The

cycle

shaft

is

driven by means

of

a spring

clutch.

The

clutch

is

allowed

to

engage

whenever

a

character

keylever

is

depressed.

The

cy-

cle

shaft powers the positioning

of

the

typehead

to the desired

character.

Its rotation

is

re$tricted

to

180

0

each

time a

char-

acter

prints. After

180

0 rotation

the

spring

clutch

is

disen-

gaged

allowing

the

shaft to remain

stationary.

The

cycle

clutch

is discussed fully in a

later

section.

2.1

Print Shaft

lFi

I

ter

Shaft

FIGURE

6.

Drive Mechanism

Through a series

of

idler

gears

at

the

left,

two

other

shafts

are

driven by

the

cycle

shaft

~ach

time

it

operates

(Fig.

6).

They

are

the

filter

shaft

and

the

print

shaft.

The

filter

shaft

oper-

ates

the

characterselectior.l mechanisms,

the

print

escapement,

the

shift

interlock,

and a

spacebar

lockout

device.

The print

shaft

operates

the print mechanism, type

aligning

mechanism,

and

ribbon feed and lift mechanisms.

The shaft

to

the

right

of

the

cycle

clutch

pulley

hub is

the

operational

cam shaft

(Fig.

6).

All powered functional

oper-

ations

are

driven by its

rotation.

The functions involved

are

spacebar,

backspace,

tabulation,

carrier

return,

indexing,

and

shift.

The shaft also controls

the

speed

of

the

carrier

during a

tab

operation.

Each

of

the

functions

is

discussed in

detail

in

its own

section.

The

operational

cam shaft is driven by

the

cycle

clutch

pulley

hub and

isin

continuous rotation

whenever

the

motor

is

running.

The right end

of

the

shaft

operates

in a

self-aligning

porous

bronze

bearing.

The

left

end

extends

into

the

cycle

c1utclh

pulley

hub where

it

is

supported by a vinyl

sleeve

(Fig.

7).

The

sleeve

provides a snug fit for

the

shaft in

the

hub

to

pre-

Cycle

Clutch

Pulley

Hub

Torque Limiter

Hub

Sleeve

FIGURE

7.

Operational

Cam Shaft Drive

Connection

3

vent

any

noise due

to

vibration.

The driving

connection

be-

tween

the

cycle

clutch

pulley

hub

and

the

operational

shsft is

made by two extensions

of

the

hub

that

fit into

cut-outs

in

the

left

side

of

the

torque limiter

hub.

The torque limiter hub is

held

in position

at

the

extreme

left

end

of

the

shaft by two set

screws. Two nylon inserts fit into

the

cut-outs

of

the

torque

limiter

hub (around

the

extensions

of

the

cycle

clutch

pulley

hub).

The inserts provide a noiseless driving

connection

be-

tween

the

two hubs.

Just

to

the

right

of

the

torque limiter hub

are

three

spring

clutches

and

two small pinion

gears.

These components

are

part

of

the

carrier

return

and

tab

mechanisms

and

are

di~ussed

in

their

particular

sections.

TYPEHEAD

Carrier

Assembly

The printing

element

is a ball shaped

typehead

containing

eighty-eight

characters.

The

type

head

is supported in front

of

the

paper

by a framework

called

the

carrier.

The

carrier

is

the

box-shaped

casting

that

moves

laterally

just in front

of

the

platen

(Fig.

8).

Its purpose

is

to

transport

the

type

head

and

other

along

the

writing

line.

Almost

the

entire

print mechanism

is

contained

within

the

carrier

as-

sembly.

In

addition,

the

carrier

also supports

the

ribbon,

rib-

bon feed and

lift

mechanisms,

and

a

bracket

that

controls

the

left

and

right margins on

the

paper.

FIGURE

8.

Front

Carrier

Support

At

the

front

of

the

carrier,

a

sleeve

fits into two bronze

bear-

ings in

the

carrier

(Fig.

8).

The

sleeve,

called

the

print

sleeve,

must rotate

within

the

carrier.

It

also slides

left

to

right on

the

printshaft

to

provide

the

front support for

the

car-

rier.

An

oil soaked

felt

ring surrounds

the

print shaft

and

is

enclosed

in a

retaining

cup

at

each

side

of

the

carrier.

As

the

carrier

moves,

the

felt

ring,

called

the

print shaft

wiper,

spreads a light film

of

oil

on

the

shaft

to

lubricate

the

sliding

ofthe

print

sleeve.

Oil

from

the

print shaft wipers is also

ab-

sorbed by

the

bearings in

the

carrier

casting

to

lubricate

the

rotation

of

the

print

sleeve.

Carrier

Support -Early

The front

edge

of

the

escapement

rack

serves as a rail on which

the

rear

of

the

carrier

rides

(Fig.

9).

The

escapement

rack

is

located

on the powerframe just

to

the

rear

of

the

carrier.

A

square block

attached

to

the

rear

of

the

carrier

sl

ides

along

the

escapement

rack.

A simi

lar

block

beneath

the

escapement

rack

prevents upward movement

of

the

carrier.

The mounting stud

forthe

upper block has

an

eccentric

shoulder

to

provide

an

ad-

justment for

the

up

and

down

play

at

the

rear

of

the

carrier.

Escapement Rack

FIGURE

9.

Rear

Carrier

Support (Early)

Carrier

Support -Late

The

late

carrier

support

(Fig.

10)

differs from

the

early

style

iin

that

the

upper shoe fits loosely on its

eccentric

mounting

stud

and

is

spring loaded

against

the

top

surface

of

the

es-

capement

rack.

This spring

load,

provided by a

leaf

spring,

removes

the

play

between

the

lower shoe

and

the

bottom of

the

escapement

rack

thereby

eliminating

any

vertical

play

of

the

rear of

the

carrier

during a print

operation.

The bottom

~hoe

is

a nylatron

block

mounted

to

a

plate

that

is

fastened

to

the

rectr of

the

carrier

by

the

same stud

that

mounts

the

up-

per

shoe.

A

stud,

riveted

to

the

plate,

anchors

the

left

end

of

the

leaf

spring.

The right end of

the

spring presses

against

the

underside

of

the

escapement

bracket

(Fig.

10).

FIGURE

10.

Rear

Carrier

Support

(late)

4

Rocker

The rocker

is

a pivoting platform

located

within

the

rear

por-

tion

of

the

carrier

(Fig.

11).

Its

purpose

is

to

carry

the

type-

head

to

and

from

the

platen

for

the

print

operation.

Compon-

ents

involved

in

the

type

head

positioning

and

aligning

opera-

tions

are

also

contained

within

the

rocker.

The rocker pivots

on

the

rocker shaft

at

the

rear

of

the

carrier.

Two bushings,

pressed

into

the

rocker,

pivot on

the

shaft

and

act

as

the

bearing surface for

the

rocker.

A

C-clip

on

the

right

side

of

the

rocker shaft prevents side

play

in

the

rocker.

A

stee

I

thrust washer

at

the

left

of

the

rocker

acts

as a

latera

I

bearing

surface for

the

rocker.

Attached

solidly

to

the

top

of

the

rocker

platform is

the

yoke

(Fig.

11).

The yoke has two arms

that

extend

up

to

provide

a pivot mount for

the

ti

It

ring.

Mounted

at

the

top

of

the

ti

It

ri

ng

is

the

upper ba

II

socket

to

which

the

type

head

is

attached.

As

the

rocker pivots up in

front,

the

yoke moves

the

ti

It

ring

and

the

typehead

toward

the

platen.

Upper Ball

Socket

Tilt Ring

FIGURE

11.

Rocker Assembly

(Gear

Tilt)

Typehead

Before printing

can

occur,

the

desired

character

must be in

po-

sition

to

strike

the

paper.

The

surface

of

the

typehead

con-

tains four bands

of

raised

characters

with

twenty-two

in

each

band (Figs. 12

and

13).

Each band has

eleven

lower

case

characters

in

the

hemisphere facing toward

the

platen

and

eleven

upper

case

characters

in

the

hemisphere facing

away'

from

the

platen.

At

rest,

the

position

of

the

typehead

is such

that

the

middle

character

of

the

upper band

is

in position

to

strike

the

platen.

This

is

the

home

position.

If

any

character

other

than

the

Platen

Upper

Case

Hemisphere

Lower

Case

Hemisphere

Type Head

FIGURE

12.

Type

Head

and

Platen

-Top

View

home position is

desired,

the

head

must

be

ti Ited up

and/or

rotated

in

either

direction

unti I

the

desired

character

is

in

the

printing

position.

Any lower

case

character

may be

reached

by

rotating

the

typehead

up

to

five positions in

either

di

recti

on

and

ti It'ing

the

headi as much as

three

bands from

the

rest

position.

The

typehead

always

rotates

back

to

the

home

or rest position

after

a

character

has

been

typed.

If

an

upper

case

character

is

desired,

the

head

must be

rotated

counter-

clockwise

an

additional

180

0 so

that

the

upper

case

hemis-

phere

of

the

typehead

is

toward

the

platen.

The

single-unit

typehead

has

the

advantage

over

conventiona

I

typebars

of

be-

ing

relatively

inexpensive

and

easily

detached

from

the

print

mechanism.

This

enables

the

operator

to

chcmge

quickly

and

easi

Iy

from

one

type

style

to

another

merely

by

replacing

the

typehead.

Lower Case Home Spring

Clip

Platen

Type Head

FIGURE

13.

Type

Head

and

Platen

-Side

View

The

type

head

fits around a post

ca

lied

the

upper ba

II

socket

at

the

top

of

the

rocker

assembIy

and

is

he

Id

in p

lace

by

a

spring

clip.

The spring

clip

is

located

on

top

of

the

typehead

and

fits

into

a

groove

in

the

top

of

the

post

(Fig.

14). A

con-

ves

disc,

covers

the

spring c

Ii

p

except

for

two

ears

(Fig.

12

and

13). The

ears

of

the

spring

clip

are

used in removing

and

instalIing

the

head.

By

pressing

the

two

ears

together

the

spring c lip

is

disengaged

from

the

groove

in

the

mounting post

a

1I0wi

ng

the

head

to

be s

lipped

up

and

off.

5

Type Head

Type Head Retaining

Clip

FIGURE

14.

Type

Head

Mounting

The

typehead

may

be

installed

by

pressing

the

ears

of

the

spring

clip

together

and

slipping

the

head

into

place.

The

typehead

is

keyed

to

the

upper

ball

socket

by a pin so

that

it

can

be

installed

in

one

position

only

(Fig.

14). The

head

must be

rotated

as

it

is

instalied unti I

it

drops

into

position on

the

pin.

The spring c lip

is

then

released

to

lock

the

head

in

place.

When

the

mechanism

is

at

rest,

the

typehead

is

always

in

the

home

position.

When

the

shift mechanism

is

in

the

low -

er

case

position,

the

ears

of

the

head

clip

are

toward

the

front

of

the

machine.

TILT

MECHANISM

Tilt

Operation

The purpose of

the

ti

It

mechanism is

to

raise

the

rear

of

the

typehead

to

the

desi red

character

band

so

that

a

character

in

that

band

may be brought

to

the

printing

point.

The

upper

ba

II

socket

is

attached

to

a

platform-like

part

ca

lied

the

ti

It

ring.

The ti

It

ring pivots on two pins

between

yoke

arms

that

fit up inside

the

hollow

of

the

typehead.

The yoke

assembly

is

fastened

to

the

rocker

to

complete

the

typehead

mounting

(Fig.

11).

The ti

It

ring

is

located

at

about

the

center

of

the

typehead.

As

the

ti

It

ring pivots on its

pins,

it

causes

the

typeheadto

ti

It.

Because

the

typehead

rests

with

the

upper

band

in

the

print

position,

all

tilt

operations

are

upward from

the

rest

po-

sition.

Early

Style

(Gear

Ti

It)

Movement of

the

ti

It

ring

is

accomplished

by

the

operation

of

two

beveled

gear

sectors

located

directly

beneath

the

tilt

ring

(Fig.

15).

One

sector

forms part

of

the

tilt

ring,

while

the

other

is

a

part

of

the

ti

It

sector

tube.

Rotati'on

of

the

tilt

sec-

tor

tube

causes

the

ti

It

ring

and

typehead

to

be

tilted.

The

tilt

sector

tube

operates

through

the

yoke

and

extends

be-

low

the

rocker.

A

pulley

called

the

tilt

sector

pulley

is

at-

tached

to

the

bottom

of

the

tube.

The pu Iley

is

he

Id

to

the

tube

by a

set

screw

that

presses a sma

II

T

-shaped

block

agai

nst

a

flat

surface

on

the

tube.

The

pulley

is

held in a

clockwise

di

recti

on (looki

ng

from

the

top) by

an

extension spri

ng.

A

sma

II

stee

I

tape

enci

rc les

the

pu lIey

and

has

one

end

attached

to

it.

When

the

tape

is

pulled,

it

causes

counterclockwise

rotati

on

of

the

ti

It

tube

and

an

accompanyi

ng

ti

It

of

the

type-

head.

When

the

pu

lion

the

tape

is

re

laxed,

the

ti

It

pu

lIey

Tilt Ring

Spacer

Ti

It

Sector

Gears

Tilt Sector Tube

Tilt Pulley

FIGURE

15.

Tilt Mechanism (Early) -Rocker Portion

is restored by its spring causing

the

type

head

to

return

to

the

rest

position.

From

the

pulley,

the

ti

It

tape

is

guided

through

the

hollow left

end

of

the

rocker

shaft

by

a rounded

tape

guide

block

attached

to

the

bottom

of

the

rocker.

The

ti

It

tape

ex-

tends

to

the

left around a sma

II

pu

"ey,

back

to

the

right

a-

round a simi lar

pulley,

and

is

attached

to

the

right

side

of

the

carrier.

This

arrangement

allows left

to

right movement

of

the

carrier

without disturbing

the

position of

the

typehead

(Fig.

16).

The

pulley

on

the

right is

solidly

mounted

and

is

moved for

adjustment on

Iy.

The left pu Iley

is

attached

to

a pivoting

arm

ca

lied

the

ti

It

arm.

Movem ent of

the

arm

to

the

left

ex-

erts a

pu

II

on

the

ti

It

tape

to

cause

a

rotation

of

the

tiIt

tube

and

a ti

It

to

the

typehead.

left

Hand Tilt

Pulley

,

Tilt-2

latch

Tilt-1

latch

.:~:::

....

late

Style

(Gearless

Ti

It)

The "gearless

tilt

m~chanism"

operates

basically

the

same as

the

previous mechanism. Movement

of

the

ti

It

ring is

ac-

complished

by

the

operation

of

the

tiIt

pulley

(Fig.

17).

A

pu

II

on

the

tape

causes

the

ti

It

pu

lIey

to

rotate

(about its

mounting stud) transferring motion

to

the

tiIt ring by means

of

the

tilt

pulley

link.

When

the

pull on

the

tape

is

relaxed

the

tilt

pulley

is

restored

to

rest

by

its

extension

spring.

FIGURE 17.

Gearless

Tilt

(late)

The

ti

It

pu

IIey link

is

fastened

to

the

ti

It

pu

Iley

by

a ba

II

shouldered

rivet

to

allow

the

link

to

pivot in

all

directions.

The

other

end

of

the

link is fastened

to

the

tilt

ring by a pin

and

C-clip.

FIGURE

16.

Tilt Tape System

6

Latch Sai I

The

cycle

shaft

has five

double

lobed cams mounted on

it

(Fig.

18).

Two

positive

cams,

one

5-unit

,:am

and

two

latch

pusher

cams.

The

two

positive

and

one

5-unit

cam provide

the

motion

to

position the·

typehead.

The positive cams

are

paired

to

operate

the

latch

bai I

located

beneath

the

cycle

shaft.

The

5-unit

and

latch

pusher

cams

wi

1/

be

discussed

later.

t.....::-----

Positive Cams

Latch Bail

FIGURE

18.

Cycle

Shaft

and

LCltch

Bail

The

cycle

shaft powers

the

positioning

of

the

typehead

by

operating

the

selector

latch

bai I. The

latch

baiI

is

a

box-

shaped

frame

located

just

beneath

the

cyc

Ie

shaft

(Fig.

18).

Two short arms

of

the

frame

extend

forward where

they

pivot

on a shaft mounted

to

the

powerframe. Each

si

de

of

the

latch

bai I

contains

a

roller

that

is

constant

Iy

in

contact

with its

re-

spective

cyc

Ie

shaft

cam.

An

extension

spring

at

the

rear of

the

latch

bai I

applies

a

constant

upward pressure

to

hold

the

rollers

against

the

cams.

Each

time

the

cye

Ie

shaft

operates

1800,

the

bai I

is

forced down pivoting

about

the

bai I shaft

and

is

a 1I0wed

to

return

to

its upward positi

on.

The rear of

the

latch

bai I

is

recessed

at

six

points.

All six

of

the

recesses

contain

selector

latches.

Across

the

rear

of

the

latch

bai I

is

a

plate

attached

by two

screws.

Each

selector

latch

has a lip formed

to

the

rear

just under

the

bai I

plate

(Fig.

19).

An

extension

spring holds

each

latch

to

the

rear.

Five

of

the

selector

latches

are

components of

the

differential

POl

Positive Cam

~

o @ 0

Selector

latch

01

~l

;;==-*

Latch Bail

\ ,

: 0

\1

\ / ;

"--------<-

-~--

Latch Bail

Plate

FIGURE

19.

Latch Bail

-SidE~View

7

lever

assembly

that

determines how much

tilt

and

rotate

the

head

wi

II

receive.

The first

and

third latches

to

the

left

are

concerned

with ti Iting

the

head,

whi

Ie

the

three

on

the

right

deal

with rotating

the

head.

The

second

latch

from

the

left

is

referred

to

later.

If

the

latches remain

to

the

rear

under

the

plate,

they

wi

II

be

pulled

down when

the

bail

is

operated.

If

any

latch

is

held

forward,

it

is

not hooked

under

the

baiI

plate

and

wi

II

not

be

pulled

down during

an

operation

of

the

latch

bail.

The

meth-

od

of

operating

the

various latches forward

is

discussed in

later

secti

ons •

Tilt

Differential

The two

tilt

latches

are

attached

at

each

end

of

a short

lever

by ball shouldered rivets

(Fig.

20).

The ball shape

of

the

shouldersallows

the

latches

to

pivot in

all

directions.

The

lever

isattachedbyadouble

vertical

link

to

the

tilt

bellcrank.

The

bellcrankpivotsonastudat

the

top

of

the

differential

bracket.

The

connection

of

the

double

Iink

is

not in

the

middle

of

the

lever;

therefore

the

leverage

developed

by one

tilt

latch

is

greater

than

that

of

the

other.

Tilt Tape

Left Side Frame

Tilt Bel/crank

Tilt

Pulley

Tilt-2

Latch Latch

FIGURE

20.

Tilt Differential At

Rest

A horizontal Iink

connects

the

top

of

the

tilt

bellcrank

to

the

tilt

arm.

Operation

of

the

bel/crank

forces

the

tilt

arm

to

the

left

to

exert

a pull on

the

tilt

tape.

The

tilt

arm

is

sometimes

referred to as the'

tilt

multiplying

arm,

because

the movement

ofthehorizontallinkisincreasedatthepulley

due

to

the

lever-

age

deve

loped.

The left hand

tilt

pulley

is

mounted

to

the

tiIt arm on a ball

shouldered pivot

screw.

This allows the

pulley

to

remain

hori-

zonta

regardless

of

the

position

of

the

tilt

arm.

It

must remain

horizontal

to

prevent

the

tilt

tape

from

coming

off

the

pulley.

The

tilt

bel/crank

is

rotated

by a pull on

the

tilt

latches.

When

the

left

latch

is held

to

the

front whi Ie

the

right

one

remains

to

the

rear,

only

the

right

latch

is

forced down by

the

latch

bail

(Fig.

21).

As

the

latch

pulls down on its

attached

lever,

the

left

end

of

the

lever

pivots

against

a stop lug formed

out

from

the

differential

bracket.

The vertiCal Iink

from

the

lever

is

FIGURE

21.

Tilt - 1

Operation

then

pulled to

operate

the

tilt

bellcrank.

The same

action

occurs

if

the

left

latch

is

pulled

down by

the

latch

bail

while

the

right

latch

is

held forward. The

distance

the

vertical

link

is pulled is not

the

same for both

latches,

because

the

link is

not

connected

to

the

middle

of

the

lever.

When

only

the

right

latch

is

being

operated

by

the

bail,

the

left

end

of

the

lever

is not

pulled

down

and

acts

as a pivot

point.

The

vertical

Iink is

attached

to

the

lever

one-third

of

the

distance

from

the

pivot point

to

the

right

latch.

This causes

the

Iink

to

be

pulled

down

only

one-third

as far as

the

latch

is

pulled

by

the

bail.

The movement

of

the

link is sufficient

to

cause

the

typehead

to

ti

It

a

distance

of one band of

characters.

This places

the

second band

from

the

top

in

the

printing

posi-

tion.

When

only

the

left

latch

is

operated,

the

right

end

of

the

lever

acts,JS a pivot point

(Fig.

22).

The

vertical

link is

then

two-

thirds

ofthe

distance

from

the

pivot point

to

the

operating

latch

and

is moved

two-thirds

as much as

the

latch.

This movement is

sufficient

to

cause

the

typehead

to

ti

It

a

distance

of

two bands

of

characters.

The third band is then in

the

printing

position.

FIGURE

22.

Ti

It - 2

Operation

When both

latches

remain

to

the

rear

under

the

latch

bail,

both

are

operated.

The

lever

moves straight down and

neither

end

acts

as a pivot point

(Fig.

23).

This causes

the

double

vertical

link

to

receive

the

same motion as

the

latches,

resulting in

three

character

bands

of

ti

It.

The fourth band is then in

the

printing

position.

8

\

FIGURE

23.

Tilt - 3

Operation

When

operated

by

itself,

the

right

tilt

l.atch causes a

tilt

of

one

character

band;

therefore

it

is referred

to

as

the

tilt-one

latch.

Because

the

left

latch

causes a

tilt

of

two

character

bands, it

is

called

the

tilt-two

latch.

Both

latches

operated

together

cause

a

tilt-three

bction.

ROTATE

MECHANISM

Rotate

Operation

The

rotate

mechanism rotates

the

type

head

clockwise or

coun-

terclockwise

to

the

desired

character

within a

tilt

band.

The upper

ball

socket

to

which

the

typehead

is

attached

has a

shouIder

at

the

bottom

fitted

into

a hole in

the

ti

It

ring

(Fig.

24A).

The fit

is

very

c lose

yet

permits free rotary motion of

the

upper

ball

socket.

The upper

ball

socket

is held in

place

by

the

tilt

ring

spacer.

The

spacer

attaches

directly

to

the

tilt

ring

and

fits around a flange

of

the

upper

ball

socket.

The

tilt

ring

spacer

is shimmed

to

allow

rotation

of

the

upper

ball

socket

yet

restrict

up

and

down

play.

Upper Ball Socket Tilt Ring

Spacer

FIGURE

24A.

Rotate Mechanism (Early)-Rocker Portion

The

under

side

of

the

upper

ball

socket

is

hollow

and

forms

the

socket

for a ba

II

joint

connection

(Fig.

24B). A

dog-bone

shaped

ba

II

joint

fits

into

the

socket

over

a pin

that

extends

through

the

socket.

The

ball

joint

is

identical

at

both

ends.

The lower

end

fits

over

a pin in

the

lower be

II

socket.

These

two

ball

and

socket

connections

act

as universal joints

to

per-

mit

the

type

head

to

be

rotated

and

ti Ited

at

the

same

time.

/

--

~

Upper Ball

Socket

(\

/\--~

"J.

_;--~~I

~

B~I

Joint

)

\ )

~--

lower

Ball

Socket

FIGURE 24B. Rotate Mechanism -Rocker Portion

The lower

ball

socket

is part

of

a shaft

called

the

rotate

shaft.

The shaft

operates

inside

the

hollow

of

the

tilt

sector

tube

and

extends

well

belowthetiltsectorpulley.

(On

the

gearless

tilt,

the

tilt

sector

tube

and

the

tilt

pulley

have

been

eliminated.

The

rotate

shaftoperatesdirectly

inside

the

hollow

of

the

yoke.)

On

both styles

the

bottom

of

the

shaft pivots in a

hole

in a

plate

attached

to

the

bottom

of

the

rocker.

This

plate

acts

as a

bearing

for

the

bottom

of

the

rotate

shaft.

Attached

near

the

bottom

of

the

shaft is

the

rotate

pulley

similar

in

operation

to

the

ti

It

sector

pu Iley

(Fig.

24B).

By

means

of

the

upper

and

lower ba

II

sockets

and

the

ba

II

joi

nt,

the

rotate

pu lIey

oper-

ates

to

rotate

the

typehead

in

either

direction.

As

on

the

ti

It

mechanism,

the

rotate

pu

lIey

is

operated

by

a

stee

I

tape

that

passes

around

two

side

pu Ileys

and

attaches

to

the

carrier.

When

either

of

the

side

pu

lIeys moves

away

from

the

other,

the

typehead

is

rotated

counterc

lockwise by

the

pu

II

of

the

tape.

When

either

side

pulley

moves

toward'the

other,

the

typehead

is

rotated

clockwise

by

the

tension

of

the

rotate

pulley

spring

(Fig.

25).

The

rotate

spring

is

of

the

mainspring

type

enclosed

in a

sta-

ti

onary

cage,

with

the

outer

end

of

the

spri

ng

attached

to

the

cage.

The

inner

end

of

the

spring

is

connected

to

a hub on

the

rotate

pulley.

A spring

of

this

type

must be used

here

rather

than

an

extension

spring as

is

used on

the

tilt

sector

pulley,

be-

cause

the

typehead

is

required

to

rotate

almost a full

revolu-

tion.

The right hand

rotate

pulley

is

attached

to

the

shift arm

and

moves

only

during

the

shift

operation;

therefore

consider

it

to

be

stationary

for

the

present.

The

left

hand

rotate

pulley

is

attached

to

the

rotate

arm.

When

the

arm moves

away

from

the

side frame, it

exerts

a pull on

the

tape

to

rotate

the

typehead

counterclockwise.

This

direction

is known

as

the

positive

direc-

tion

of

rotation.

When

the

left

hand

rotate

pulley

moves towards

the

sideframe,

the

rotate

spring turns

the

rotate

pulley

rotating

the

typehead

in a

clockwise

direction.

This

direction

is known as

the

nega-

tive

direction

of

rotation.

Positive Rotate

Differential

The

rotate

differential

is

much

the

same as

the

tilt

differential.

The

latches

are

operated

by

the

latch

bail

if

they

are

allowed

to

remain

to

the

rear

under

the

baiI. Each

operates

with

a di

f-

ferent

leverage

for

different

amounts

of

rotation.

Rotation

of

upto

five

characters

is

sometimes

required

on

either

side

of

the

rest

position.

This requires more

latches

and

levers

than

for a

tilt

operation.

Rotate Spring

Shift

Arm

---

___

FIGURE

25.

Rotate Tape System

9

Consider

the

positive

rotation

of

the

typehead

first.

Three

latches

and

a series of

three

levers

are

involved in positive

Ilotation

(Fig.

26).

The

three

latches

are

those farthest

to

the

right

in

the

latch

baiI. All

the

latches

are

spring loaded

to

the

rearunderthe

latch

bail

and

are

operated

by

the

bail unless

they

are

pulled forward.

Rotate Tape

Rotate Bellcrank

Ba

lance

Lever

FIGURE

26.

Rotate Differential At

Rest

The two

latches

on

the

extreme right

are

mounted by ball

shoul-

dered rivets

to

a short

lever

similar

to

the

tilt

latch

mounting.

A flat double link

extends

vertically

from

the

lever

to

a second

lever

above

it.

The

connection

is

at

the

right

end

of

the

second

'lever

and

one-third

of

the

distance

from

the

right

end

of

the

fi

rst I

ever.

The third

latch

is

connected

by a ball shouldered

rivet

to

the

left

end

of

the

second

lever.

Because its mounting point is

higher

than

the

other

latches,

the

third

latch

is much longer

than

the

others to permit

latching

under

the

baiI

at

the

bottom.

A second

vertical

Iink

connects

the

second

lever

to

the

left

endofthethird

lever

in

the

series.

The link is

attached

to

the

second

lever

two-fifths

of

the

distance

from

the

right

end.

The third

lever

is an

adjustable

lever

connected

at

the

middle

to

the

horizontal arm

of

the

rotate

bell

crank.

It

is referred

to

as

the

balance

lever,

because its adjustment

balances

the

amount

of

motion between positive and'

negative

rotation.

The right

end

of

the

balance

lever

is held

stationary

during positive

ro-

tation.

Adownward pull

at

the

left end causes

the

rotate

bell-

crank to

operate.

A

heavy

link

connects

the

bottom

of

the

rotate

be

II

crank

to

the

bottom

of

the

rotate

arm. The

rotate

arm is sometimes referred to as

the

rotate

multiplying arm

be-

cause

the

movement

of

the

rotate

Iink is increased

at

the

pulley

asa result

of

the

leverage.

Operation

of

the

bellcrank

counter-

clockwise causes

the

rotate

arm

to

pivot

about

its fulcrum point

and

exert

a pull on

the

rotate

tape.

In

order

to

operate

the

ba

lance

lever for a positive

rotate

cyc

Ie,

one or more of

the

latches must be

pu

lied down by

the

latch bai

I.

Consider

the

latches one

at

a time starting with

the

middle of

the

three

rotate

latches.

When only

the

middle

latch

is

allowed

to

remain under

the

latch

bail,

it

is

the

only

one pulled down when

the

bai I operates (Fig.

27).

As

the

middle latch

is

pulled

down, its

attached

lever moves down

10

at

the

left

and

pivots

at

the

right on a stop lug formed out

from

the

differential

bracket.

The

vertical

link is

attached

to

the

lever

one-thi

rd

of

the

distance

from

the

pivot point

to

the

latch.

This causes

the

link

to

be moved down

one-third

as much as

the

latch.

This Point

Stationary

On

All Positive

Selections

FIGURE

27.

Positive -

One

Rotate

Operation

The link

exerts

a pull on

the

right end

of

the

second

lever

caus-

ing it

to

pivot on its stop lug

at

the

left

end.

The second

ver-

tical

link is

attached

to

the

lever

three-fifths

of

the

distance

from

the

pivot point to

the

operating

end

of

the

lever.

The

second link moves

three-fifths

as much as

the

right

end

of

the

lever.

The right end

of

the

second

lever

moves

one-third

as

much as

the

latch.

Multiplying

the

two

together,

the

second

vertical

link moves

three-fifteenths

or

one-fifth

as much as

the

latch.

The second

vertical

link

operates

the

left

end

of

the

balance

leverwhich,

in

turn,

actuates

the

rotate

bellcrank.

This

move-

ment is sufficient

to

cause a positive rotation

of

one

character

on

the

type

head.

The movement is caused by

operation

of

the

middle

rotate

latch,

so it

is

referred

to

as

the

rotate-one

latch.

When

only

the

right hand

latch

is

operated,

the

movement

of

the

rotate

bellcrank

is

doubled,

and a positive rotation

of

two

characters

is

obtained

on

the

type

head.

The increased

move-

ment is

obtained

at

the

first

lever.

When

the

right hand

latch

moves down,

the

lever

pivots on a stop lug

at

the

left.

The

vertical

Iink is

attached

two-thirds

of

the

distance

from

the

pivot point

to

the

latch;

therefore

the

link moves down

two-

thirds as much as

the

latch.

This is

twice

as much as for

the

rotate-one

latch.

The right hand

latch

is referred

to

as

the

rotate-two

latch.

When both

the

rotate-one

and

rotate-two

latches

are

operat-

ing

together,

the

first

lever

moves straight down without

pivot-

ing

at

either

end

(Fig.

28).

This gives

the

same amount

of

motion to

the

first

vertical

link as is given

to

the

two

latches.

Movement

of

the

link is

three

times as much as when

operated

by

the

rotate-one

latch

alone.

The

additional

movement

is

transferred to

the

rotate

bell

crank

to

rotate

the

type

head

three

characters

in

the

positive

direction.

When

additional

rotation is

required,

the

third

rotate

latch

must

be used. The left hand

latch

is

never

used

alone;

but

to

clarify

its

leverage

in

relation

to

the

other

latches,

consider

it

to

be

the

only one in

operation.

FIGURE

28.

Positive -Three Rotate!

Operation

The

left

hand

latch

is

attached

directly

to

the

end

of

the

sec-

ond

lever.

When

operated,

the

latch

causes

the

left

end

of

the.

second

lever

to

move

down.

The right

end

of

the

lever

cannot

rise so

it

acts

as a pivot

point.

The

second

vertical

link

is

attached

to

the

lever

two-fifths

of

the

distance

from

the

pivot

point

to

the

latch;

therefore

the

link moves down

two-fifthsas

.

much as

the

latch.

Movement

of

the

link is

twice

as much as when

the

rotate-one,

latch

isoperatedalone.

Therefore

the

movement

obtained

from,

the

left

hand

latch

is

sufficient

to

rotate

the

type

head

two

Negative

Rotation

Positive

rotation

of

the

typehead

is

achieved,

by

operating

the

rotate

bellcrank

counterclockwise

so as to

create

a pull on

the

rotate

tape.

It follows

then

that

operating

the

rotate

bell-

crank

clockwise

wi

II

allow

the

rotate

pulley

spring

to

rotate

in a

negative

direction.

The

rotate

bellcrank

is

controlled

by

the

balance

lever

in

the

differential

series.

In

order

for

the

bellcrank

to

operate

clock-

wise,

the

balance

lever

must be

raised.

The

left

end

of

the

lever

cannot

rise,

because

the

stop lugs on

the

bracket

prevent

any

upward movement in

the

lever

series.

Therefore

if

the

bell-

crank

is

to

operate

clockwise,

the

right

end

of

the

lever

must

be

raised.

The right

end

of

the

balance

lever

has a

flat

link

connection

to

the

five-unit

bai I assembly

(Fig.

30).

The baiI is a

single

arm

located

under

the

cycle

shaft

and

pivoted

in front on

the

bail

shaft.

When

the

five-unit

bail

is

allowed

to

rise,

the

right

end

of

the

balance

lever

rises

to

allow

clockwise

operation

of

the

rotate

bellcrank.

5-Unit

Drive Link

characters

in

the

positive

direction.

Since

the

right hand

latch

E--==--m:II-.--~

iscalledthe

rotate-two

latch,

the

left

hand

latch

is

referred

to

as

the

rotate-2A

latch.

The

2A

latch

is

never

used by

itself.

When

its motion

is

added

to

that

of

one

or both

the

other

latches,

rotation

of

four or five

characters

can

be

obtained.

The

rotate-one

latch

is used for

one-character

rotation

and

the

rotate-two

latch

for

two-

character

rotation.

Both

are

operated

together

for

three-

character

rotation.

The

rotate-two

and

rotate-2A

latches

are

operated

for a

four-character

rotation.

The

rotate

-one,

rotate-

two,

and

rotate-2A

are

operated

for a

five·-character

rotation

(Fig.

29).

FIGURE

29.

Positive -Five Rotate

Operation

11

FIGURE

30.

Five Unit Bail At Rest

The

five-unit

bail

is

prevented

from

rising by

the

five-unit

latch

at

the

rear

(Fig.

31).

The

latch

is

mounted

to

the

di

f-

ferential

bracket

and

pivots front to

rear.

In

the

rest position

the

latch

is

positioned

above

the

head

of

an

adjusting

screw

at

the

Latch

Prevents

Bail From Rising

-

FIGURE

31.

Five-Unit

Bail During Positive Rotate

Cycle

rear

of

the

five-unit

bai I. When

the

latch

is

operated

for-

ward

the

bai I

is

a

II

owed

to

rise

(Fig.

32).

The force whi

ch

raises

the

bail

comes from

the

rotate

pu

Iley spring

and

the

spring

attached

to

the

rotate

arm.

These springs

are

applying

a

constant

force on

the

rotate

bellcrank

in

the

clockwise

di-

recti

on.

Latch Allows Bail

To

Rise

FIGURE

32.

Five-Unit

Bail During

Negative

Rotate

Cycle

The

five-unit

bail

is

restored down by

the

extreme

right

hand

cam on

the

cycle

shaft.

The high point

of

the

cam

is

90°

from

the

high

point

of

the

other

two

cams.

This insures

that

when

the

latch

bail

is

driven

DOWN

in

the

active

position,

the

five-

unit

baiI

can

be

UP

in

the

active

position.

Conversely,

when

the

latch

baiI is

UP

in

the

rest

position,

the

five-unit

baiI wi

II

be

DOWN

in

the

rest

position.

It

should be

noted

that

the

five-unit

bail

is

held

down in

the

rest position by

the

cam

rather

than

by

the

five-unit

latch.

In

the

rest position

there

is a

clearance

between

the

latch

and

the

adjusting

screw in

the

five-unit

bail.

The

clearance

must

be present

to

insure

resetting

of

the

latch

at

the

completion

of

a

cycle.

During a positive

rotate

or

no

rotate

cycle,

the

five-unit

bail rises

slightly

before

being

restricted

by

the

five-

unit

latch

(Fig.

31).

This upward movement

of

the

five-unit

bail

allows

a slight

clockwise,

or

negative

rotation

of

the

type

head.

The

type

head

rotates

from

the

rest position

to

a position

known

as

the

"latched-home"

position.

Consider

all

positive

and

negotive

rotations

to

occur

from

the

latched-home

position.

Movement

of

the

five-unit

baiI

from

the

latched-home

point

to

the

low

point

of

the

cam

allows

sufficient

clockwise

movement

ofthe

rotate

bellcrank

to

permit a five

character

negative

rota-

tion

ofthe

typehead

(Fig.

33).

If

less

than

five units

of

nega-

FIGURE

33.

Negative-Five

Rotate

Operation

12

tive

rotation

is

desired,

it

is

necessary

to

pull down on

the

left

end

of

the

balance

leveras

the

right

end

goes

up.

This

reduces

the

amount

of

clockwise

movement

of

the

rotate

bell

crank

•

Operating

one

or

more positive

rotate

latches

down in con

junc-

tion

with

allowing

the

five-unit

bail to rise allows

different

amounts

of

negative

rotation.

The

positive

rotate-one

and

negative-five

combine to

allow

a

negative-four

rotation.

A

positive-two

and

negative-five

combination

gives

a

negative-

three

rotation

(Fig.

34).

A

positive-three

and

a

negative-five

operation

permits a

negntive-two

rotation.

A

positive-four

plus a

negative-five

combination

givesa

negative-one

rotation.

FIGURE

34.

Negative-Three

Rotate

Operation

KEYBOARD

SECTION AND CHARACTER SELECTION

The

keyboard

section

is

a

compact

unit

that

contains

all

the

keylevers

and

allied

parts,

and

a

selection

mechanism for

the

differential

latches.

Depression

of

any

printing

keylever

pre-

pares

the

selection

mechanism for

operation

and

trips

the

cy-

cle

clutch

latch

to

allow

a

cycle

operation.

Keylevers

The

keylevers

pivot

on

a fulcrum rod

at

the

rear

(Fig.

35).

A rubber

covered

rod limits

the

upward

travel

of

the

keylevers

and

the

bottom

of

the

guide

comb slots Iimit

the

downward

travel

of

the

keylevers

in

the

front

guide

comb.

A lower

ex-

tension on

each

keylever

operates

in

the

keylever

bearing

sup-

port

to

stabiI

ize

the

keylever.

The keybuttons

are

designed

in

the

shape

of

a pyramid

to

make

the

use

of

a

keyplate

unnecessary.

The tops

of

the

keybuttons

form

a

concave

slope

to

the

keyboard

for

ease

of

operation.

Keylevertension

issupplied

bya

set

of

flat

spring fingers under

the

front

of

the

keylevers.

The forward

end

of

each

spring

finger

is

cupped

so

that

the

spring

wi

II

maintain

its position

under

the

keylever.

Different

spring

tension

is

supplied

to

the

four rows

of

letter

keylevers

by

auxi

I

iary

leaf

springs

under

the

keylever

springs. The auxi I

iary

spring fingers

vary

in

length

to

offset

the

leverage

difference

among

the

four rows

of

key-

levers.

This

variation

in spring tension results in a uniform

operating

force

requirement

for

all

keylevers.

A

shoulder

rivet

attaches

a

keylever

pawl

to

each

keylever

at

the

rear.

A small spring

attached

from

the

pawl to

the

keyle~er

holds

the

pawl in

the

rest

position.

The pawl

extends

below

and

is

formed

under

the

keyleverin

position to strike

the

top

of

an

interposer

(Fig.

35).

Selector

Latch

FIGURE

35.

Keyboard

Section

and

Character

Selection

Adjusting

lugs just

to

the

rear

of

the

top

row

of

keybuttons

make

it

possible

to

adjust

the

relative

height

of

each

individual

key-

lever

and

keylever

pawl.

Interposers

Each

keylever

ha~

a

character

interposer

located

just

below

it

(Fig.

35).

The purpose

of

the

interposers

is

to

select

the

amount

of

tiIt

and

rotate

needed

to

bring

the

desi

re~d

character

to

the

printing

point.

A

large

fulcrum rod passes

through

an

elongated!

hole

in

the

front

of

each

interposer

and

provides a support on

which

the

interposers

can

pivot

and

sl

ide.

A

guide

comb

at

the

front

and

rear

separates

the

interposers.

The interposers

are

allowe-dtomove

up

and

down in

the

rear

guide

combaswell

as

front

to

rear.

An

extension

spring from

each

interposer

to

the

top

of

the

rear

guide

comb .loads

the

interposer

to

the

rear

and

up

into

the

rest

position.

The

interposers

have

~several

lugs

extending

from

them,

each

with

its own

operation

to

perform

(Fig.

36).

Each

interposer

has a lug

on

top

in position

to

be

struck

by

the

keylever

pawl.

On

the

bottom

of

the

interposers

ar~

positions for

eight

lugs.

Seven

of

the

lugs

are

selective

lugs.

The

obsence

or

presence

of

these

lugs in

different

pO,sition

combinations

makes

the

inter-

posers

different.

There

are

no two

alike.

The rearrnost selec-:-

tive

lug is for

special

applications

of

the

machine.

Keylever

Pawl

Contact

Surface

Latching

Surface

Rl

R2

R2A

R5

Tl

12

c~

o

~~

Filter Shaft

S I L

Contact

Surface

e

ector

ug

Cycle

Clutch

Release Lug

F

I

GU

RE

36.

SeI

ector

Interposer

13

One

lug on

the

bottom is common

to

all

interposers.

It

is

a

wide

lug

located

at

the

middle

of

the

interposers.

Its purpose

is

to

release

the

cycle

clutch

for a

cycle

operation

whenever

a

keylever

is

depressed.

Directly

below

the

lug

is

the

cycle

bail

that

pivots up

and

down

(Fig.

35).

Downward movement

of

any

character

interposer

forces down on

the

cycle

bail to

release

the

cycle

clutch

latch

and

allow

a

cycle

operation.

The

cycle

clutch

release

lug is

cut

at

an

angle

on

the

bottom

to

prevent

interference

between

the

lug

and

the

cycle

bail as

the

parts

are

restoring

to

the

rest

position.

Fi

Iter

Shaft

When

the

interposer

is depressed

it

pushed

the

cycle

bai I down

to

unlatch

the

cycle

clutch

and

cause

a 1800

rotation

of

the

cycle

shaft

(Fig.

35).

Rotation

of

the

cycle

shaft 1800

also

rotates

the

fi

Iter

shaft 1800• The

fi

Iter

shaft is a

two-bladed

shaft

located

at

the

rear

of

the

keyboard

section

and

just

be

low

the

ends

of

the

interposers.

It

rotates

ina

beari

ng

at

each

end

and

is

connected

by a

gear

train on

the

left

si

de

of

th(

cyc

Ie

shaft.

When

an

interposer

is

depressed,

the

rear

of

the

interposer

is

moved down in front

of

one

blade

of

the

fi

Iter

shaft.

As

the

filter

shaft

turns,

the

blade

drives

the

interposer

forward

to

operate

the

character

selection

mechanism.

Interposer Latch Springs

Resting

against

the

rear

of

each

interposer

is

a spring

finger

called

the

interposer

latch

spring

(Fig.

37).

The spring fingers

are

slightly

deflected

to

the

rear

when

the

interposers

are

at

rest.

When

any

interposer

moves down

at

the

rear,

the

spring

snaps forward

over

the

interposer

and

holds

it

down.

The

inter-

poser

remains down until

it

is pushed forward

enough

to

cl'~ar

the

spring

finger.

At

that

time

it

is raised

and

restored

by its

extension

spring.

IBM Selectric I/O Manual

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