Some arrangement must be provided to move along the work by given amounts in perfect regularity, thus determining the length of the stitch. This motion must be automatic, and not dependent upon the operator beyond the determination of the amount of feed for the work from time to time. There are several mechanical ways of performing this.

* The results of a few tests taken at the eye of the needles are here given -

Wheeler's.........

No.

4

needle

= 59

Stubbs' gauge.

" ••• • • • •••

99

5

99

= 58

Jones' (Hollington's make)

99

1/2

•2

"

= 59

99

« »

"

2

99

= 67

99

" "

99

3

99

= 6')

99

" "

"

4

99

= 58

99

99 19

99

5

19

= 56

"

" "

"

7

= 53

"

99 "

99

8

5 9 99

= 51

99

9» 99

99

10

99

= 48

9'

Singer's (Hollington's) ...

99

0

99

= 60

"

99 " •••

"

1/2

•2

"

= 59

99

99 99

99

1

"

= 58

99

99 )»

99

1 1/2

"

= 56

"

Jones' (Perkins')......

99

2

99

= 67

99

" " • • •• •

99

3

"

= 60

9*

Singer's (Company's)

99

0

99

= 59

99

99 99 •••

99

1

99

= 56

>9

" 99 •••

"

1 1/2

19

= 55

99

The four-motion feed may be either a top-feed or an underfeed. In the fop-feed the pressure and motion is applied from above by means of a serrated foot, controlled by a spring. The four motions consist of (1) Application under pressure of foot to material, to clamp it as it were.

(2) The movement of the foot with the work, the determined amount to settle the length of stitch.

(3) The foot lifted from the work.

(4) The foot returns ready for repetition of motion (1). This style of feed can be found in machines constructed for flat binding, patching, repairing, etc., and is a feature of the machines illustrated on pp. 287 and 288 by Figs. 221 and 222.

The four-motion underfeed consists of a device under the work, pressure being continuously delivered from above by lowering the presser foot before commencing to sew. This enables the operator to turn the work while the needle is in it, using it as a centre to sharply turn when required, following the contour of the part being stitched.

The motions of the under-feed of this type are as follows :(1) The feed rises, and its serrated surface enters or presses up to the under side of the material being stitched.

(2) The feed, together with the work, moves forward the afore desired amount, thus deciding the length of the stitch.

(3) The teeth of the feed is lowered out of contact with the material, which is held in position by the top pressure.

(4) The feed returns ready to perform motion (1). Passing by the "drop-feed" and "draw-feed," the wheel-feed requires notice. This consists of a wheel whose periphery is serrated, and it is so arranged that it projects slightly above the plate, and thus engages the material that is pressed upon it by the foot above. The wheel revolves a given amount, as determined by the throw of the pawl. Fig. 200 is a sectional view of a wheel-feed, showing also Shuttles, Hooks, etc. - The appliances for taking the thread and forming the stitch known as a chain are termed loopers. Shuttles are contrivances for containing the spool or bobbin of under stitching material in a lock-stitch machine, and are of various kinds. They must be in any case perfectly smooth so as not to chafe the thread. The weavers or boat-shaped shuttle, familiar to most folk, is chiefly used for a type of motion known as reciprocating.

Fig. 200. Jones' patent arrangement for compensating for the wear of the stud.

Fig. 200. Jones' patent arrangement for compensating for the wear of the stud.

The reciprocating shuttle is illustrated by Fig. 201, and travels with the race lever to and fro in the same plane. Owing to the reversing at the conclusion and beginning of each complete motion, it is a form of motion only adapted with a limited range of speed. This type of shuttle is one that allows the stitching thread to be deposited with the minimum of friction caused by the see-saw passage through the eye of the needle. Less thread is paid out and taken round this form of shuttle than in any other. The amount of thread paid out as slack would be about 11/2 inches. Its objection is that the tension or strain on the thread varies as it is delivered from the centre or end of the spool, amounting to nearly 50 per cent, more strain when delivered from the ends.

For a good appearance stitch, where speed is not a vital consideration, this form of shuttle answers every requirement. Machines with reciprocating boat-shaped shuttles are not usually provided with independent take-ups, owing to the small amount of "slack "needed for the shuttle to pass through. The machines illustrated in Figs. 221 and 222 have this form of shuttle.

Fig. 201.

Fig. 201.

Fig. 202.

Fig. 202.

Fig. 203.

Fig. 203.

The oscillating shuttle is shown by Fig. 202. This shuttle contains a disc-shaped spool or bobbin, that relatively contains a large amount of thread, and is freer from the angular strain when delivering the thread. The motion is a to-and-fro one, in a restricted arc of a circle. The machines illustrated by Figs. 213 and 219 have this type of shuttle.

The rotary hook is now extensively used for sewing-machines, and is illustrated by Figs. 203 and 204, the latter also showing the bobbin case in position. It throws a twisted loop, and, owing to the size of the hook, takes a large amount of slack. Machines illustrated by Figs. 205 and 215 have this type of shuttle.

Fig. 204.

Fig. 204.

The rotary shuttle is a form not much in use, but is illustrated by Fig. 206. The block (Fig. 207) shows the spool or bobbin case closed, while Fig. 208 shows the same opened and the case removed. The bobbin case is also shown by Fig. 209.

Fig. 205.

Fig. 205.

Fig. 206.

Fig. 206.

Fig. 207.

Fig. 207.

Fig. 208.

Fig. 208.

Fig. 209.

Fig. 209.

Fig. 210.

Fig. 210.

Fig. 211.

Fig. 211.