Let-off mechanism
There are four types of let-off mechanisms for projectile looms: one is a mechanical let-off mechanism with a conventional swinging back beam; the other is a motor-type let-off mechanism with a conventional swinging back beam; the third is a mechanical let-off mechanism with a warp tensioner Mechanism; the fourth is a motor-type let-off mechanism with warp tensioner. The latter two are often used in the let-off mechanism of new projectile looms. The mechanical let-off mechanism is relatively complex, while the electronically controlled motor let-off mechanism has a relatively simple structure. The new projectile loom’s let-off mechanism adopts an electronically controlled motor let-off mechanism.
1. Mechanical let-off mechanism with warp tensioner
The mechanical let-off mechanism with warp tensioner is composed of a swinging back beam type warp adjustment device, an automatic let-off transmission device and a warp beam. The function of the warp tensioner is to control the let-off transmission device to ensure that the same number of warp yarns are always output at a constant tension without being affected by changes in the warp beam winding diameter. In addition, the warp tensioner quickly equalizes any warp tension peaks that occur in the shed of the loom. As a control element, it is used to continuously adjust the position of the swing back beam 1 to maintain a balance between the warp tension acting on the swing back beam and the reaction force generated by the square torsion bar 2. As shown in Figure 4-7. When the warp tension on the swinging back beam is large, the swinging back beam descends, and through the control mechanism connected to it, the let-off axis is accelerated to increase the amount of warp let-off; when the warp tension on the swinging back beam is small, the swinging back beam descends. Ascending, through the control mechanism connected to it, the let-off shaft is slowly driven or braked to reduce the amount of let-off.
2. Motor-type let-off mechanism with warp tensioner
The motor-type let-off mechanism with warp tensioner is mainly composed of a let-off driving motor, a reduction gearbox, a main gear device, a swing back beam sensor, and a control box , composed of swing back beam and warp beam. As shown in Figure 4-8.
The motor-type let-off mechanism with warp tensioner drives the motor 4 and its reduction gearbox 6 through the let-off. The main gear device 7 continuously rotates the warp shaft forward, so that the position of the swing back beam 3 always remains the same. The height and warp tension are also kept constant until the warp of the weaving beam is completely fed out. The position of the swing back beam 3 is determined with the help of the cam disk and the swing back beam sensor 5. When the warp tension on the swing back beam is greater, the swing back beam will drop. The swing back beam sensor 5 sends a signal to the control box 8, and the control box 8 issues instructions. , causing the let-off motor to accelerate the let-off; when the warp tension on the swing back beam is small, the swing back beam rises, and the swing back beam sensor 5 sends a signal to the control box 8, and the control box 8 issues a command to decelerate or brake the let-off motor. . Since the reduction gear 6 and the main gear device 7 are not self-locking, the let-off motor can operate efficiently. Its main feature is that it is equipped with a brake, which allows it to maintain warp tension without electricity. During the warp stop, the speed preset value of the let-off motor is still effective, so when the loom is started again, the motor can run at the correct let-off speed. If the power supply to the control box 8 is interrupted, the preset value of the speed will become invalid. In this case, the let-off motor 4 can only start at an average speed, and then be corrected to the normal speed within a short period of time. When the loom is stopped, the warp tension can be tightened or relaxed through buttons 1 and 2 on the control box 8: when the warp needs to be tightened, press button 1; when the warp needs to be relaxed, press button 2. When the two buttons are pressed at the same time, the tension of the warp yarn can be adjusted so that the back beam 3 is adjusted to the pre-adjusted position of the tension required for weaving.
The warp let-off mechanism of the P7300 projectile loom adopts an electronically controlled motor warp let-off device. The shuttle box and shuttle box adopt the same mechanism and have four different speed gears. The advantages of this let-off mechanism are:
(1) The warp tension has good uniformity and consistency.
(2) When driving, you can use slow let-off, fast let-off or delayed let-off to remove defects in the rungs when driving.
(3) The let-off mechanism has the function of sending forward or retracting backward.
(4) In conjunction with the electronically controlled fabric winding mechanism, the warp yarn can be quickly pulled.
The electronically controlled warp breakage automatic stopping device of the P7300 projectile loom. The center bracket of the warp breakage automatic stopping device is fixed on the frame. The number of center brackets depends on the machine model and can be used within a wide range. Adjusting the position of the warp stop is easy to operate and ensures a small winding angle of the warp yarn. The automatic warp breakage stop device usually has 6 rows of warp stop bars. The warp stop bar with a tooth pitch of 25mm is used for cotton yarn; the warp stop bar with a tooth pitch of 18mm is used for synthetic filament. The effective width of the loom is 190-220cm with a single-stage warp stop bar; the effective width of the loom is 280-430cm with a two-stage warp stop bar. It can also be used for models with an effective width of 190-220cm; the effective width of the loom is 460-540cm With four sections of drop bar, it can also be used for models with an effective width of 360~430cm.
AAAFGNHIYIYO
Extendedreading:https://www.yingjietex.com/product/Polyester-Oxford-cloth-plaid-Fabric.html
Extendedreading:
Extendedreading:
Extendedreading:
Extendedreading:
Extendedreading:
Extendedreading:
Extendedreading:
Extendedreading:
Extendedread
