Color Changers

A knitting machine color changer is an accessory or built-in mechanism that allows a knitting machine to swap between multiple yarn feeds (typically two to six colors) at the end of a carriage row, automatically or semi-automatically.

By eliminating the need to manually unthread and rethread the carriage feed for every color change, these units dramatically speed up the production of multi-color knits such as horizontal stripes, Fair Isle (single bed), and Double Bed Jacquard (double bed).

Core Classifications & Concepts

Color changers vary significantly in how they interface with the needle beds, how yarns are tensioned, and whether selection is manual, semi-automatic, or electronic.

Bed Configuration

• Single-Bed Color Changers: Designed for flat-bed knitting on the main bed alone. They mount on one side of the bed (usually the left) and are used for single-bed striped fabrics, slip-stitch, and tuck-stitch patterns.
• Double-Bed Color Changers: Designed to mount on or interface with the Ribber carriage or bed. They allow multi-color double-bed knitting, such as colored ribbing and floatless double-bed jacquard.
• Dual-Bed / Convertible Changers: Versatile units (such as the Silver Reed YC-6) that can be adjusted for either single-bed or double-bed operation by changing carriage connection arms, sinker plates, or adjusting the mounting angle of the changer head.

Selection Control

• Manual Selector: The knitter manually moves/slides a yarn guide or eyelet into the carriage's path before passing it.
• Semi-Automatic: The machine carriage trips the selector mechanism upon entering the changer area, but the knitter must press a button on the changer unit to select which yarn will be picked up on the next pass (e.g., Brother KRC-900, Silver Reed YC-6 in manual mode).
• Automatic (Mechanical or Electronic): The color swap is controlled without operator intervention during knitting. This can be achieved through:
  • Mechanical programming: Using trip levers, carriage settings, or punchcard/pattern readers to alternate between two colors automatically (e.g., Silver Reed YC-6 set to 2-color alternation, or Passap Duomatic mechanical selectors).
  • Electronic programming: Solenoids or electronic actuators inside the changer receive signals from the knitting machine's computer console, swapping colors automatically based on the digital pattern (e.g., Passap E6000 electronic color changers, Brother KRC-1000E).

System Architectures by Brand

The engineering approach to changing colors differs fundamentally between Japanese flatbed systems and European integrated bed systems.

Japanese Flatbed Systems (Brother, Silver Reed)

Brother (KnitKing) and Silver Reed (Studio, Singer, Empisal, Knitmaster) machines share a modular, add-on design language.

Mounting and Carriage Arms

On Japanese machines, color changers are accessories that mount on the left end of the needle bed. To use them, the standard carriage arm must be replaced:

• Brother KRC/KHC: A specialized double-bed setting arm (or single-bed sinker plate) replaces the standard one. The arm features a gate/coupling system that enters the color changer head and swaps yarn feeders.
• Silver Reed YC: Uses a dedicated yarn changer connector arm replacing the standard sinker plate/arm, which mechanically interacts with the YC unit to drop and grab the yarn shuttles.

High-Tension Yarn Masts

Because inactive yarns hang from the left side of the machine, Japanese systems require specialized tension masts:

• The mast features long, flexible, high-tension wire springs (often called antennas) for each color.
• When a yarn is inactive, the spring pulls the slack yarn high above the needle bed, preventing loops or loose strands from catching on the carriage or edge needles.

Key Models

• Brother KRC-830 & KRC-900: 4-color semi-automatic double-bed changers. The KRC-900 is adjustable, allowing it to fit both standard-gauge (4.5mm) and bulky-gauge (9.0mm) setups.
• Brother KHC-820: A 4-color single-bed changer.
• Brother KRC-1000E: An electronic 6-color automatic changer that connects directly to Brother electronic machines.
• Silver Reed YC-3 & YC-5: 4-color ribber-only changers.
• Silver Reed YC-6: A popular 4-color dual-purpose (single or double-bed) changer that can alternate two colors automatically or four colors via button presses.

European Integrated Systems (Passap)

Passap (primarily Duomatic and E6000) machines utilize a highly integrated double-bed design where accessories mount directly onto the machine's structural frame.

Slider Eyelets & Rail Integration

• Passap does not use detachable carriage arms or sinker plates for color changing. The locks (carriages) run permanently on the machine's steel guide rails.
• The color changer unit mounts directly onto the left rail extensions.
• Instead of swapping carriage feeders, the yarn is threaded through small plastic/metal yarn eyelets (yarn feeders/shuttles).
• These eyelets sit in a rack on the color changer. The back lock (rear carriage) has a face cam (tripping cam) that strikes the plastic control levers (nubs) on the color changer, which drops the selected eyelet into the lock's path or parks the inactive one.

Tension System

• Passap does not use long, high-tension spring antennas.
• Instead, it uses a central tension mast with spring-loaded tension discs and internal yarn brakes (friction cups) to maintain tension, combined with the lock's yarn guide path.

Key Models

• Duomatic 4-Color Changer: A mechanical unit for the Duomatic 80. The knitter selects colors by pressing mechanical levers on the changer. The back lock automatically catches the active eyelet.
• E6000 Electronic Changer: An automatic unit that interfaces with the E6000 console. Solenoids inside the changer unit push the correct control levers down based on the program, enabling fully automated multi-color knitting (up to 4 or 6 colors).

General Operation & Best Practices

While mechanisms differ, successful multi-color knitting relies on several shared principles:

1. Carriage Travel / Over-travel: The carriage must travel completely past the color changer unit at the left end of the bed (usually until a distinct click is heard or the carriage clears the gate) to allow the mechanics to fully release the old yarn and lock in the new one. Reversing the carriage too early will cause a jam. 2. Stroke Speed: Maintain a smooth, steady, and slightly slower speed when entering and exiting the color changer gate to prevent yarn carriers from skipping, dropping, or misaligning. 3. Tension Balancing: Because multi-tension masts and color changers introduce additional friction, the carriage tension dial may need to be adjusted (often opened up by half to a full unit) to maintain a consistent stitch gauge compared to single-color knitting. 4. Yarn Tail Management: When starting a new color, the yarn tail must be anchored (typically secured to the table clamp or a weight) to ensure the first stitch forms correctly at the fabric edge.

Troubleshooting

• Dropped Edge Loops: If the inactive yarn forms a loose loop at the left edge of the fabric:
  • On Japanese machines: Increase the tension on the mast wire or check for yarn tangles on the mast.
  • On Passap machines: Ensure the yarn brake on the tension mast is operating correctly and the eyelet is sliding freely.
• Carriage Jams: Usually caused by reversing the carriage before it has fully completed its leftward travel, leaving a yarn carrier half-engaged. Clear the jam by manually releasing the carriage arm or lifting the eyelet.
• Broken Selector Nubs (Passap): If the back lock strikes the control levers too hard, it can shear them off. This requires adjusting the height of the back lock's face cam so that it only makes light contact with the nubs.
• Needle Collisions: On Japanese machines, ensure the setting arm is adjusted to the correct height using its mounting screws. If it sits too low, it will hit the gate pegs or needle latches on the left.