Personally, I have met four types of threaders:
automatic,
semiautomatic device,
device built into the machine
и loop device.
You can look at the work of a semiautomatic device and devices on my video...
The operation of the "full" machine in the English-language video below.
Of course, automatic threading in a carpet is the dream of any home fashion designer, but the cost of such a pleasure exceeds one and a half thousand dollars.
You have had the pleasure of watching the Baby Lock's exclusive instant air-threading system in action. Indeed, it is like a fairy tale: with one press of the lever of the device located on the front cover of the sewing machine, the thread is instantly and automatically blown through the tubular loopers.
Semi-automatic systems themselves are cheaper, but they are also not installed on cheap equipment. Brohter sewing and embroidery machines are an example.
But, devices such as a hook, which unscrupulous sellers of sewing equipment pass off as an automatic threader, have nothing to do with the machine.
Such devices, as a rule, are supplied with cars of medium and economy classes.
In general, when choosing a machine, pay attention to the threader, since one of the indicators of the equipment class is the threader.
См. также "Tips for buying sewing equipment"