10 Shuttleless looms

B. A. Muralidhar

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In the conventional loom the shuttle performs the functions of holding, transporting and laying a predetermined length of weft yarn across the fabric width as it traverses from one shuttle box to another across the width of the loom. This whole process from the mechanical point of view is accomplished by considerable energy dissipation as the shuttle has to be accelerated rapidly and must also be decelerated abruptly.


Further, other limitations associated with the conventional shuttle looms being the use of a large wooden shuttle weighing roughly about 450 to 500 grams (in cotton and worsted weaving) to transport a relatively small quantity of weft yarn, requirement to frequently replenish the small weft package,the periodic change in weft tension, as a result of weft unwinding from a full pirn to a near empty pirn thereby, influencing the fabric properties, limited scope to increase the loom speed and very high levels of noise emanating.


In view of the preceding considerations, the unconventional shuttle merely preforms the function of carrying a pick of weft, unwound from a stationary cone across the warp shed. In order to accomplish the above function the weft carriers were considerably reduced in size and mass. This further lead to reduction in the shed depth and the sley sweep. By adapting these modifications it became evident that the loom with unconventional weft insertion system could run at much higher speed, with higher productivity and produce superior quality wide width fabrics. These unconventional loom are generally referred to as “Shuttle-less looms”. Commercially manufactured shuttle-less looms are generally classified based on the type of carrier and its passage across the shed. The carrier may either be fluid (or) solid and its flight may be guided, positively controlled (or) absolutely free.


In the projective weaving machine, the entire concept of picking is different from the conventional picking mechanism. Here, the weft is inserted by a much smaller bullet like shuttle or carrier about 90 mm long and weighing about 40 grams. This element is denoted as either gripper (or) projectile. The gripper/projectile draws the weft into the warp shed directly from a large cross wound package and a metal torsion rod propels the gripper projectile through the shed. The torsion bar is made out of special metal, and is twisted to store energy required to propel the gripper projectile. The speed of the projectile is entirely dependent on the torsional angle of the bar. The projectile on being accelerated from rest enters the reed space and follows a specific path created by rakes within the warp. These rakes prevent the projectile from flying out of the shed.


The main parts of the picking mechanism include a torsion bar (A), picking shaft (B), picking lever (C), picking shoe (D), picking shaft lever (E), toggle plates (F) and picking cam (I) as shown in the figure 1.


On rotation of the picking cam (I) in the clockwise direction the cam nose slowly displaces the roller (G) turning the toggle plates F in the clockwise direction about their centre (O). In doing so the toggle plates and the link (H) are extended thus twisting the torsion bar A through the picking shaft (B). Further, as the picking cam (I) continues to rotate the cam nose will lose contact with the toggle plate roller (G) and the cam roller (R) runs onto the curved part of the plates (F) causing the system to collapse. Thus causing the twisted torsion rod (A) to release the torsion accelerating the gripper projectile (P) through the picking shaft (B), picking lever (C) and picking shoe (D). Following this the picking lever is brought to rest by the oil brake (L).


The beat-up mechanism in the projectile weaving machine is different from the conventional looms. Here the sley is positively rocked about its centre by matched cams. The sley carries a reed and number of projectile guides. During beat-up of the weft the guides moves down from the shed and lie below the fell of the cloth.


Figure 1. Projectile loom picking mechanism (A-Torsion bar, B-Picking shaft, C-Picking lever, D-Picking shoe, E-Picking shaft lever, F-Toggle plate, G-Antifriction bowl, H-Link, I-Picking cam, J-Shaft, K-Bevel wheels, L-Oil-brake, P-Projectile).


In a rapier loom, the weft insertion is carried out by a rapier device in which the weft thread is held at its tip by the carrier rapier and transferred to the receiver rapier. Mr. Johann Gabler is regarded as the father of modern rapier. Rapier weaving machines are broadly classified based on the type of rapier (that is rigid rods, flexible metals, plastic tapes or bands), number of rapiers, method of weft insertion and the positioning of the weft insertion mechanism.


Insertion of a double pick:


In this technique, the weft yarn is threaded through a hole at the tip of the rapier and is widely used in tape and carpet looms. With this technique conventional selvedge are formed on the weft supply side, while at the other side the selvedge is formed by either a catch cord or by knitting.


Insertion of single pick with single rapier


During the loom cycle in this process a single rapier is inserted across the whole width of the loom shed and then withdrawn. The weft yarn is either inserted during rapier insertion or rapier withdrawal. The main advantage of this system is that the problem of weft transfer is avoided. However, since the rapier has either idle forward or backward movement, the loom speed is comparatively slower than other rapier looms.


Two phase rapier


In the two phase rapier looms the rigid rapier is driven from the centre and has rapier head at each end. In one cycle the rapier inserts one pick alternately in the right and left hand fabrics, and beaten-up in opposite phase.


Double rapier weft insertion with loop transfer (Gabler system)


In the double rapier system, two rapiers enter the shed from the opposite ends and the weft yarn is transferred from one rapier to the other when they meet at the centre and there after they are withdrawn. Thus both rapier insertion and withdrawal is used for weft insertion. With a single weft supply, the weft may be introduced as a loop upto the middle of the loom and upon transfer to the other rapier, the transferred lop is straightened our during rapier withdrawal from the shed.


Weft insertion principle (Gabler system)


In the Gabler system, the weft is supplied form cross wound packages placed on the right side of the loom. The weft is inserted by two flexible rapiers, in two pick weft insertion cycle to form a smooth and uniform conventional selvedge at right hand side of the cloth and an unconventional leno selvedge at the left hand side. The cyclic operation of weft insertion is shown in stages in Figure 2 (a) to (i).

Figure 2. Gabler weft insertion system (A-Right hand rapier, B-Left hand rapier, C-Weft supply package, D-Weft clamp, E-Weft positioner, F-Weft depressor, G-Weft gripper, H-Weft cutter, I & J-Weft guide components).

  1. As shown in at (a) both the rapiers are about to enter the shed. The weft is correctly positioned and the end of the weft is firmly held by gripper (G).
  2. When both the rapiers have entered the shed, the weft depressor (F) moves back, and the rapier is drawing weft from the package.
  3. Both the rapiers meet at the centre of the loom and the loop is about to be transferred to the receiver rapier. Further the weft clamp is closed to stop weft supply from the package.
  4. The free end of the weft is drawn through the remainder of the shed, simultaneously the depressor moves back for the next pick.
  5. The pick is fully inserted
  6. The beat-up of the weft is completed and the rapier advance towards the shed.
  7. The rapier enters the shed and the weft is slipped off the weft guide components (I) & (J).
  8. The weft is cut by the cutter (H) and both the rapiers meet at the centre.
  9. The transferred loop is again straightened during the rapier withdrawal, in this way the second pick of the cycle is laid.

Double rapier weft insertion with tip transfer (Dewas system)


In this system the weft is transferred directly from one rapier tip to the other rapier tip. For this system a yarn clamp is required on the heads of both the rapier. Alternately in another system, the yarn clamp is transferred from one rapier to the other rather than the weft yarn being transferred. The principle of weft insertion in Dewas system is shown in figure 3.

      Figure 3. Dewas weft insertion system.


In Dewas system the supply packages are mounted separately. The weft yarn passes through the thread eye (B) and a weft tensioner device (C). The weft yarn further passes to the vertical selector needle, number of needles depend on the number of weft colours used. Downward movement of needle places the weft at rapier level and is selected for pick insertion. The weft insertion cyclic operation is as follows:


1.   The needle presents the weft to the advancing rapier, which grips the weft as it enters the shed.

2.  At this point the previous pick still connected is cut off by the knife blade.

3.  The rapier (right) continues to move and reaches the loom centre a little early and is opened by opener lever (H) at this point the left rapier inserts the weft yarn into the opened right rapier. As soon as the weft yarn is secured by the right hand rapier, the rapier withdraws from the shed drawing the weft from the package. After reaching beyond the selvedge the weft is released in this way the weft insertion cycle continues.




In an air jet loom the weft yarn is inserted pneumatically, using compressed air flow through the shed by the main and relay nozzles. Weft insertion by air and water jet looms, offer considerable advantages such as low noise level and its ability to weave wide range of fabrics at high weft insertion rates. In the air and water jet looms, the energy is stored by compressing them, and releasing some of this energy to propel the weft across the loom. As the weft yarn to be carried across the loom weighs a few milligrams, the weft propulsion attains high velocity within a short time.


Air jet looms offers more practical and lucrative solutions because of air’s low density and high availability. The working principle of the commercially available Maxbo Murata air jet loom is outlined below:


A typical sequence of weft insertion on an air jet loom is as follows. The weft yarn A is measured by a measuring drum B equivalent to the cloth width, is inserted into the shed by  nozzle D which sprouts the weft yarn across the loom by compressed air, after picking, the slack yarn is drawn back. On the other side of the loom, the suction tube H guides the inserted weft and inhales.


The weft insertion cycle is depicted in Figure. 4 (a – f).

Figure 4. Weft insertion sequence on Air jet loom.


(a) The positively drawn out weft is measured by the measuring drum (B)

(b) On weft insertion, the needle J catches the weft yarn on the other side of the loom

(c) The weft thread straightener C draws back the weft yarn which has been sprouted beyond the cloth edge, to tack up the weft slackness.

(d) The rotating measuring drum winds the weft, the straightener retracts the weft back to the cloth edge, the reed moves forward and the air jet nozzle now has stopped sprouting the weft.

(e) At the time of beat-up the cutters (E) on both sides of the loom cut the weft yarn about 6 mm to the edge of the cloth.

(f) The cut weft yarn hangs down the nozzle, at this point the straightener moves in and draws back the weft yarn to the nozzle tip.


The air jet loom requires quality compressed air of about 5.0 bar at the inlet of the loom and about 7 bar at the exhaust point. Moisture in compressed air must be eliminated in all cases, as moisture leads to corrosion of metallic parts, obstruction to air flow by adhering to foreign particles and further it tends to produce tiny holes on the pipe line leading to air leakages.


Traverse aids for maintaining air flow:


The speed of the air along the line of the nozzle, which is the pick path falls rapidly beyond the orifice. One way to overcome this is by means of a multi ring confuser mounted on the sley. Theconfuser move in and out of the shed for every pick, this make it difficult to weave heavy warp density fabrics. To overcome this problem profile reeds which act as an air guide are more commonly used.


The weaving principle of a water jet loom is similar to an air jet loom, the only difference being that water is used instead of air. However, only hydrophobic yarns can be used in weaving on these looms. Moreover, the loom operates on only one nozzle, thereby limiting the fabric range and fabric width that can be woven on water jet looms.


Of the other shuttle less looms, the water jet loom is the least flexible as the range of fabric woven is limited to medium weight and the yarn must be hydrophobic. Further, the maximum width of the loom is restricted to 230 cm thus leaving little flexibility in the dynamic clothing market. However the water jet looms are best suited for manufacturing 100% synthetic fabrics and these loom are least noisy and require the lowest energy to operate.


The weft yarn from the cone/cheese passes over a guide roller and through the tensioning device to the measuring drum; from there it passes through the cramper/gripper to the picking nozzle. The cramper/gripper regulates the insertion of weft in the shed. Weft insertion on a water jet loom depends on many factors such as:

  • The quantity of water jetted out of nozzle The water pressure
  • Nozzle cross-section
  • Opening / closing of the cramper with respect to water jetting angle Measuring length of yarn
  • Nozzle position

Let us briefly sum up the topicscovered in this module on shuttle less looms. In this lesson, we introduce you to the different principles of weft insertions in an unconventional shuttle less looms. Then we have introduced the viewer to the mechanism of weft insertion by the projectile system followed by the mechanism of weft insertion by rapier loom. In the rapier system, we have deliberated on both the Gabler and the Dewas systems of weft insertion. Then in the latter part of the module we have deliberated on the mechanism of weft insertion by the Air-jet followed by the mechanism of weft insertion by water jet looms.


The unconventional shuttle less loomsthat have been very successful commercially are the projectile looms, the rapier looms andthe air jet loom because of their versatility and flexibility, allowing the manufacturer to produce a range of fabric with varying, count, end/pick density widths etc.

you can view video on Shuttleless looms



  1. Talukdar M. K., Sriramulu P. K., Ajgaonkar D. B. 1998. Weaving-Machines-Mechanisms-Management, Mahajan Publishers Private Limited, Ahmedabad, INDIA.

Web links


  • http://nptel.ac.in/courses/116102017/