The SHRP Weft Feeder is one of the main components of a weaving machine. It is supplied with different outfits and has different adjustment possibilities. These include yarn count, yarn type and insertion system. Generally, the feeder has an independent motor. The speed of the motor can be adjusted in a wide range. Sometimes, the feeder motor can be interlinked with the driving unit of the weaving machine.
Dynamic drum winding weft feeder
A dynamic drum winding weft feeder is one type of a weft feeder that uses the rotating drum to wind the weft yarn. The weft yarn must be tied to the leading end of the drum before winding. When unwinding, the weft yarn slides along the drum surface. Because of the friction between the weft yarn and the drum surface, weft yarn should be carefully selected.
There are two basic types of drum winding machines. The first type uses a drum to wind the yarn, while the second type uses a drum fixed in place. Each type has a positive or negative yarn guide. It can also be set to use a fixed-length or non-fixed-length unwinding mode. The fixed-length type is appropriate for water-jet and air-jet looms, while the non-fixed-length type is used on projectile looms.
Coil-measured fixed-length unwinding
The SHRP Weft Feeder is a fixed-length unwinding device that takes a weft thread from a reel. The device includes a success-nozzle to brake the outgoing thread and a processing unit on board. This unit detects the relative elec! radiation from the yarn and adjusts the speed of unwinding as needed.
When a yarn passes through the detection area, a pulse signal is generated. This signal is received by a control device that counts the number of pulses received. The count value corresponding to each pulse corresponds to the actual position and length of the yarn withdrawal point from the storage drum.
Photoelectric sensors
A weft feeder with photoelectric sensors has a stationary cylinder with multiple independent sectors (T). One of these sectors has emitting sensors embedded in its thickness. The other sector has a relative feeding and control circuit. The emitting sensors are located opposite the extension (10) of the main body (1) of the weft feeder.
The SHRP weft feeder has two main parts. The inner portion (T) includes emitting sensors, and the outer portion (W) has a feeding and control circuit positioned between the two sections. The latter comprises wired emitting sensors and a flexible printed circuit.
Mechanical sensors
The mechanical sensors on the SHRP weft feeder have two types: one has emitting sensors R and the other has receiving sensors E. The former is located on the lateral surface of the stationary drum and the latter is located on the support arm. The emitting sensors are arranged in a pattern such that their relative electric signals are based on the presence of thread passing through its path.
The mechanical sensors of the SHRP weft feeder are designed to detect buckling of the strip. The sensors detect buckling by detecting changes in tension T of the strip. They are mounted between the feeder and the die, and they are made of a post that is fixed on a hinged arm. When a strip buckles, the sensor actuates and outputs a signal that is sent to the controller.
Brush to avoid thread loop caused by yarn unwinding
In SHRP weft feeders, the weft yarn is wound onto the storage drum through a yarn guide tube. This drum then loops on a transmission shaft. The permanent magnets that hold the drum to the machine body ensure that the weft yarn maintains a uniform tension under tensioner action. Hence, it is important to carefully consider the thread loop while operating this feeder.
When the yarn is too loose, the warp threads break randomly. This is because the reed tries to beat the weft into a narrower weave than the warp. Moreover, if this situation is not corrected, it will only get worse over time.
