Jo Ann's Knitting Blog

The Carriage

The carriage (picture 25) is made up of two metal plates linked by a stiff bridge (P); the plates work individually and simultaneously on the front and the rear needle-beds.

The carriage carries out a double function and can be used:

1. to select the needles and make them raise or lower to form the stitch;
2. to select and drive the thread guides which feed the needles.

The plates include cam locks (F) bearing the drive and control systems of the needles, i.e. the cams.

When the carriage moves right- or leftwards, the thread guides (B),(C),(D),(E) are locked individually by the corresponding pistons (A) on the upper part of the bridge, that are manually driven.

Brushes are also mounted on the carriage to ensure a smooth needle latch opening and grant a correct feeding of the yarn.

Picture 25 - The carriage

The Cam-locks

The cam-locks (picture 26) are a cam system which gives the necessary working information to the individual needles; they include a fixed part, working as support, and movable cams, which can be divided into raising cams and lowering or knock-over cams (2). The raising cam includes:

• A tucking cam (1).
• A looping cam (3).

The fixed or movable cams form a symmetrical channel where the needle butt slides; the needle moves downward and upward in the groove to form the stitch.

Picture 26 - Cam-lock of a flat knitting machine

The different parts of the cams are chamfered; their profiles are curvilinear to make the needle move smoothly.

The angle of inclination of the cams ranges between 40° and 50°; these values grant an optimum running of the needle and avoid high pressures between metal parts during the motion and excessive tensions on the yarn during the downward stroke of the needle.

The carriage allows three different work ways according to the needle stroke and to the positions of the raising cam:

• KNIT STITCH: when the needle carries out a complete stroke, reaching the maximum height on the looping plane
• TUCK STITCH: when the needle reaches the tucking plane and receives a new yarn while still holding its former loop, thus forming two loops in the one needle hook
• MISS (or FLOAT) STITCH: when the needle is not knitting and remains out of the knock over plane.

The raising cam, both tucking or looping, can be :

A. Closed or sunk cam

CARRIAGE STROKE

BUTT NEEDLE

BUTT NEEDLE

CARRIAGE STROKE

B. Half-way cam

CARRIAGE 4-

STROKE

BUTT NEEDLE

BUTT NEEDLE

CARRIAGE 4-

STROKE

C. Open cam

CARRIAGE STROKE

BUTT NEEDLE

BUTT NEEDLE

CARRIAGE STROKE

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