How Silver Reed Knitting Machines Work¶

Introduction to Knitting Machines¶

Silver Reed knitting machines are domestic machines designed in the 1980s-1990s. They allow knitting pieces much faster than hand knitting.

Main Components¶

The Carriage¶

The carriage is the moving part that travels left to right across the needle bed. It:

Forms stitches by pulling yarn through loops
Selects which needles should knit
Detects its position and direction using sensors

Key difference from Brother machines: On Silver Reed machines, the carriage contains all the patterning logic: - Sensors send information to the "patterning brain" inside the carriage - Solenoids (electromagnets) act on selected needles to either select or skip them

The Needle Bed¶

The bed contains 200 needles numbered sequentially. Each needle can be in different positions:

Position A (back): the needle knits
Position B (forward): the needle is in hold
Position D (very forward): the needle doesn't knit (pattern)

The Solenoids¶

Solenoids are electromagnets that control needle selection. The firmware activates/deactivates these solenoids to create the pattern:

Solenoid activated: the needle knits
Solenoid deactivated: the needle skips (doesn't knit)

Operating Principle¶

1. Carriage Movement¶

The carriage moves manually from left to right and vice-versa. On each pass:

The carriage detects its direction using the HOK signal (HIGH when moving from right to left)
It detects needle positions using the CCP signal (Carriage Clock Pulse) - one CCP period equals one needle
For each needle, the DOB state (Data Out Buffer) selects or skips the needle

2. Needle Selection¶

For each carriage pass:

┌─────────────────────────────────────────────┐
│  Carriage moves →                           │
│                                              │
│  CCP: ┐  ┐  ┐  ┐  ┐  ┐   (1 pulse/needle)  │
│       └──┘  └──┘  └──┘                       │
│                                              │
│  DOB: ──┐     ┐  ┐     (1=knit, 0=skip)     │
│         └─────┘  └─────                      │
│                                              │
│  Result: ■  □  ■  ■  □  (knitted pattern)   │
└─────────────────────────────────────────────┘

3. Electronic Signals¶

The machine uses a 7-pin circular DIN connector to interface with the electronics:

DIN-7 Connector Pinout (front view, looking at female socket):

        2
    4       5
  1           3
    6       7

The firmware reads and controls several signals:

DIN Pin	Signal	Type	Direction	Description
1	ND1	Digital	Input	Pattern position (not used)
2	KSL	Digital	Input	Point CAM detection - detects sections
3	DOB	Digital	Output	Data Out Buffer - controls the needle
4	CCP	Digital	Input	Clock Pulse - counts needles
5	HOK	Digital	Input	Carriage direction (LEFT/RIGHT)
6	5V	Power	Supply	Global power supply (5V)
7	16V	Power	Supply	Solenoid power supply (16V)
8	GND	Ground	Common	Common ground

Technical Details¶

Direction Detection¶

The HOK signal (Hall Sensor) indicates direction:

HOK = HIGH: carriage moving left ←
HOK = LOW: carriage moving right →

The firmware reverses the pattern reading order based on direction.

Pattern Zones (Sections)¶

The KSL signal detects pattern sections based on Point CAMs (magnets) placed on the needle bed:

Needle Bed with Point CAMs:
┌────────────────────────────────────────┐
│  [CAM]                        [CAM]   │  Point CAMs (magnets)
│────┬──────────────────────────┬────────│


KSL Signal:
         Pattern Zone (between CAMs)
         ┌──────────────────┐
KSL: ────┘                  └────
    LOW                         LOW

KSL = HIGH: Carriage is between the pattern CAMs (knitting pattern zone)
KSL = LOW: Carriage is outside pattern zone

This allows the firmware to know when to activate pattern selection and optimize communication by only transferring data for the active zone.