A common weft-knitting cycle uses a latch needle guided by cams. As the needle rises, the old loop slides below the latch and opens it; yarn is fed into the open hook; then the descending needle closes the latch, draws the new loop and lets the old loop knock over.
Knitting Machine Interactive Calculator
Convert an entered course rate and needle stroke to cycle time and average travel speed. One-third cycle time is a numerical comparison, not a measured stitch-stage duration.
Equation Used
- One entered course is treated as one complete needle cycle.
- Cycle distance is twice the entered stroke.
- The visual shows one representative latch needle and omits adjacent-needle, sinker and take-down dynamics.
- No yarn-force, loop-length, acceleration, wear or safe-speed model.
The stitch stages are not equal thirds, and no machine-specific cam law or dwell is supplied.
Latch-needle stitch sequence
The needle rises under cam control so the previous loop slides down the stem and opens the latch. At clearing height the new yarn is placed in the hook. During descent the old loop closes the latch and passes over the hook while the needle draws the new loop.
What the visual explains
The animation identifies clearing, yarn feed, loop draw and knock-over. It cannot set a safe machine speed or predict fabric quality.
Rate and travel-speed conversion
With C courses per minute and one needle cycle per course, T=60/C seconds, or 60,000/C milliseconds. Cycles per second are C/60. A complete out-and-back travel covers 2s, giving average travel speed 2s/T for stroke s.
The one-third-cycle output is T/3. It does not represent a cam dwell or a feed, clearing or knock-over interval. Average travel speed is distance divided by time, not signed average velocity or peak speed.
Reading the cycle and timing
The purple path represents an old loop, the green path incoming yarn, and the red member a needle latch. Their assigned positions illustrate the stitch stages without a yarn-contact model.
At C=3,000 courses/min and s=10 mm, the assumed cycle time is 20 ms, rate is 50 cycles/s, one-third cycle time is about 6.67 ms, and average travel speed is 1,000 mm/s. These conversions do not establish a suitable operating speed for a machine.
Needle motion and model limits
A latch needle’s hook and closing latch cooperate with the old loop and incoming yarn to form the next loop. The drawing shows the sequence conceptually; it does not calculate contact between yarn and needle, and the drawn latch changes length between its two assigned positions.
Stroke adjusts the illustrated travel. Playback is slowed and limited to at least one second per cycle, so its speed is not the actual needle rate. No cam acceleration, yarn tension, loop length, take-down or machine capacity is calculated.
Frequently asked questions
Is peak speed shown?
No. The calculation divides the total out-and-back travel by the cycle time. Peak speed and acceleration require the motion law.
Is one-third cycle time the yarn-feed duration?
No. It is just the complete cycle time divided by three; the illustrated stages have separately assigned timing.
Does course rate always equal needle cycle rate?
The calculator assumes one complete needle cycle per entered course. That relationship must match the intended machine operation for the conversion to apply.
Does the animation calculate yarn contact?
No. The needle, latch and loops use assigned positions and are not a contact or fabric-formation simulation.
Needle and stitch references
Groz-Beckert, Flat knitting illustrates latch-needle behavior and loop formation, including the function of spring-loaded latches.
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