White 1570 manual Materi

A

THE

TENSION

What happens

now,

if

the

upper

tension is

too weak?

drawn from

At

the

moment

the

lower

thread

should

he

too

its

resistance

becomes

the

stitch,

the

bobbin

to

finish

upper

tension.

Thus

the

strong

in

relation

to

the

upper

is drawn

into

thread

the

lower

before

thread

in

unwound

no

longer

meets

-up

lever

thread

the

.

The

take

material

from

the

upper tension

to

enable

with enough

resistance

thread

and

the

hewer

the

material

the

thread

to

cross

in

remains

tretched

(Fig.

4

C).

What happens,

if

the

upper

tension

is

too

tight?

from

At

the

moment

the

lower

thread

should

be

drawn

weak

in

is

too

the

stitch,

its resistance

the

bobbin

to

finish

un

The

lower

thread

thus

tension.

relation

to

the

upper

resistance

to

does

not

offer

enough

winds

too

freely and

The upper

thread withdraws

thread.

the

pull

of

the

upper

stretched

on

top

and

remains

entirely

from

the

material

through

it

crosses

right

lower

thread

of

it.

whilst

the

(Fig. 4

8).

the

upper

It

is

most

important

that

the

functioning

of

explained

in

adjusted

be

it

should

be

tension

and

how

detail

to

the

user.

Fig.

5

Fig.

5

starts by

showing

a perfect

seam, then

a

skipped

(B).

Skipped

stitches

stitch

(A)

and

then

a

broken

thread

another,

the point

of

are

caused

when, for

one reason

or

of

the

upper

thread.

the

hook does

not catch

the

loop

regardless

of

what

shuttle

On

all

-stitch

machines,

lock

the

upper

thread has to form

the

systems

they may

have,

below.

loop

explained

in detail

Fig.

6

When a

threaded

needle

pierces

the

material,

the

thread

order

needle,

in

grooves

on

the

will

slip

into the

two

the

when passing

through

thus to

offer

the least

resistance

side

on

the

resistance

increases

material.

However,

this

in

the

materi

disappears

the

latter

of the

short

groove,

as

longer

in

the

groove

but

al,

because

the

thread

is

now

no

of

the

needle

and

the

is

jammed

between

the

body

stretched,

until

the

thread

remains

material.

Thus

the

point

.

6>.

needle

reaches

its

lowest

(Fig

thread

When

the

needle

starts

moving

upwards

again,

the

difficulty

be

can

slide

without

in

the

long

groove

(F)

on

the

. 7).

As

and

the

material

tween

the

needle

(Fig

it

can

not

is

jammed,

the

thread

short-grooved

side

(E)

a

small

needle

and,

therefore,

forms

slide

along

with

the

loop

on

the

same

side.

P

F

V

Fig.

7

Now the

different

shuttle

systems

come

into

play.

They

is to

pass

the

bobbin

with

all

have

the same

task, which

.

This

is

what

is

called

the

lower thread through

the

loop

.

stitch formation

4 1

—6-—