Pfaff 343, 341, 343 U-12, 342, 344 U-12 Instruction Book

56-12-09661

engl.

P 770

PrintedinGermany

;•. ?w

•:.•

•i

^

^^(s)

( PFAfF ) 341;

343;

345

and

353

Single-Needle

Cylinder-Bed

Sewing

Machines

and

"

^ .(5)

( PFAFF )

342;

344;

346

and

354

Two-Needle

Cylinder-Bed

Sewing

Machines

Instruction

Book

C)

o

1.

General

The

Pfaff 341. 343. 343 U-12

and

345

are

all cylinder-bed

sewing

machines

with right-

hand

balance

wheel

whose

vertical

hookisarrangedtothe

right of

the

needle.

The

Pfaff 353 with left-hand

balance

wheel

has

the

sewing

hook

arrangedtothe

left of

the

needle.

Both

the

Pfaff 341

and

342

are

equipped

with

compound

feed

while

the

Pfaff 343. 344

and

353

are

fitted with

ordinary

drop

feed

only.

The

Pfaff

345

and

the

Pfaff

346

both

feature

unison

feed.

All

the

afore-mentioned machines

are

equipped

with

sleeve

take-up.

The

rotating motion

of

the

top

shaftistransmittedtothe

hook

shaftbybevel

gears.

is

recommendedtomake

sure

that

the

take-up

leverisat

its

highest

point

before

oeginning or ending a seam. Observation of this rule prevents

the

thread slipping

out

of

the

needle

eye

and

thread

jamming in

the

hook raceway. It eliminates

the

necessity

of

holding

both

threads

when

beginningtosew.

The

maximum

stitch

lengthofstandard

machines

is 4.5 mm (5V2 s.p.i.).

c

It is

recommendedtorun

the

machinesatthe

following

top

speeds:

Pfaff

341

Pfaff

342

Pfaff

343

Pfaff

343

U-12

Pfaff

344

Pfaff

344

U-12

Pfaff

345

Pfaff

346

2.600

s.p.m.

2.500

s.p.m.

2.700

s.p.m.

1.400

s.p.m.

2,600

s.p.m.

1.400

s.p.m.

2.500

s.p.m.

2.400

s.p.m.

When sewing tightly woven or heavily

dressed

fabrics,

the

sewing

speed

must be

reducedtoprevent

overheatingofthe

needle.

On two-needle machines, the maximum sewing speed diminishes as the needle gauge

«creases.

To avoid trouble,

these

machines should be run at about 70% of their top

speed

until

all parts in movable

contact

have

become

thoroughly glazed by their action upon each

other.

This

should

normallybethe

case

after

about

two

weeks'

constant

use.

All machines

are

regularly

equipped

with a fixed pulley which is

castinone

with

the

balance wheel. If desired, however, the machines

can

be supplied with a disengageable

pulley.

If fitted with a disengageable pulley, the machine is dispatched with the sewing mecha
nism disengaged. To engage this mechanism, hold the balance wheel steady with your

left

hand

and

tighten

the

large

locknut by turning it clockwise.

The

spool

holderonthe

machine

armissuppliedonspecial

request

andatextra

cost

only

because

the

thread

stand

which is regularly

supplied

with

the

machine

ensures

better

thread

control.

SettingUpthe

Machine

3

machineisdrivenbya

V3-HP

clutch

motor

which,

like

all

motors

supplied

with

machines, is a squirrel-cage induction motor conforming to German

DIN

42691

deifications.

Voltage

and

typeofcurrent

are

determinedbylocal

requirements.

Power

ransmitted

from

the

motortothe

sewing

machinebya

V-belt.

When

mounting

the

elt for the

first

time,

do not force it onto the

pulley

because distorted

V-belts

wear

e

rapidly.

All

motors

are

pivotally

connected

to the

motor

bracketbymeans

of a

36

bolt (d in

Fig.

1). Loosen the nut of the hinge bolt or clamp screw k and

lift

the

or

until

the

V-belt

can be

easily

placed in the

grooves

of the balance

wheel

and

or

pulleys.

-quires some experience to correctly adjust the

tension

on the belt so as to

avoid

3ssive

pressureonthe

arm

shaft

bearings

and

the

resultant

overheating

and

sei2ln(^^

"le machine. v J

beltiscorrectly

tensionedifyou

can

compressitwith

two

fingers,

without

applying

9, by about 2 cm (abt.

V*')

midway

between both

pulleys.

'is

position,

securely

tighten

the

hinge

bolt

nut or

clamp

screw k

(Fig.

1).

1

machineisfitted

at the

factory

with

the

correct

motor

and

motor

pulleyinaccor-

'e

with

the

machine

class and the permissible top speed.

R

6835

3.

Cleaning

and

Oiling

Proper cleaning and regular

oiling

will

increase the service life of your

machine.

Before

you put the machine into operation for the first time, take a clean rag and remove the

dust

accumulatedintransitaswell

as the rust

preventative

covering

all

nickel-plated

and polished parts. Then apply a few drops of kerosene to all oiling points marked in

red on the

machine

and unthread the needle. Place a piece of

fabric

under the presser

foot and run the

machine

briefly.

Next,

apply

oil to

all

points of

friction,

using

Pfaff

sewing machine oil No. 280-1-120122 for this purpose.

All

oiling

points

are

markedbyarrowsinthe

pertinent

illustrations.Toget at the

oiling

pointsinthe

cylinder

arm

of the

machine,

loosen

wing

nutF.swing

away

latchG(Fig.

2),

and

tilt the machine back, resting it on

the

wooden machine rest.

he cotton in the hook

raceway,

which

is accessible

through

hole O

(Fig.

16).

should be

soaked

with

oil everyday. Once a week,unscrew needle plate and feed dog and remove

the

lint

which

has accumulated in the

vicinity

of the

sewing

hook,

usingatoothpick

or

similar

wooden

object.

When replacing the needle plate, make sure that position finger F of the bobbin case
base enters slot P on the underside of the needle plate

(Fig.

15).

The

bevel

gears are enclosedincases and

requirenospecial

maintenance,

except

that

the grease in the cases should be

c^ianged

once a year. For this purpose, use soda

grease

No.

280-1-120243.

Thanks to the special lubricating properties of this grease,

the flanks of the bevel gear teeth should be greased only

lightly.

R

6977

.ing trouble, suchasskipping of stitches and thread breaking,

cannot

be remedied

applying excessive quantities of oil. Excessive oiling may result in soiling of

the

?rial and heavy working of the machine

caused

by a mixture of oil residues

and

strongly

recommended

to test-run

the

machine

without

thread

and

bobbin

case.

•re

you

plug

the

machine

in,

however,

checktomake

sure

the

line

voltageisth(

j

aasthat

indicatedonthe

motor

rating

plate,

and

the

motor

pulley

turnsinthe

right

ction.

direction

of motor pulley rotation is

correctifthe

balance

wheel

turns

toward

you,

idicated

by an

arrow

in Fig. 3.

direction of pulley rotation is best checked before mounting the V-belt. If the V-belt

already

been

mounted,

dieck

the

direction of rotation by switching on

the

motor

lightly tipping on

the

pedal

while holding

the

balance

wheel

fast.

•3

pulley

turnsinthe

wrong direction,

the

maintenance

man

has

merely to

exchange

.viresatthe

motor

terminal

board.

r run a

threaded

machine

unless

you

have

fabric

under

the

presser

footorthe

ser

footIsraised.

R

6976

5.

Removing

the

Bobbin

Case

Raise

the

take-up

lever

to its

highest

position

and

open

latch

B (Fig. 4) with

the

nail of

your

thumb.

Slightly

lift

the

bobbin

case

with

the

forefingerofyour

right

hand,

as

illustrated

above,

and

takeitoutofthe

machine,

together

with

the

bobbin,

with

thumb

and

forefinger.

c^.

Winding

the

Bobbin

The

bobbinIswoundonthe

power-driven

bobbin

winder

shown

in Fig. 5.

Placeaspoolofthread

on pin 1.

Pass

the

thread

through

eyelet2,clockwise

around

and

between

tension

discs3and,

from

the

inside,

through

the

slotinthe

bobbin.

Wind

a

few

turnsofthreadonthe

bobbininclockwise

direction,

and

place

the

latteronthe

bobbin

winder

spindle.

Start

the

bobbin

winderbypressing

down lever 6.

The

bobbin

winder

will

stop

auto

matically

when

the

bobbin

is full.

The

amountofthreadtobe

woundonthe

bobbin

is

regulatedbyscrew7.Turn

this

screw

clockwise

for

more

thread,orcounter-clockwise

for

less

thread.

If the

thread

should pile up at

one

end

of the bobbin, loosen

screw

4 and

adjust

the

positionofthe

bobbin

winder

tension

bracket,asappropriate.