The rotary shuttle is an important part of the sewing machine. In the sewing equipment, the sewing machine with lock stitch is common. Most of these sewing machines use a rotary shuttle to hook the thread loop with its tip, while expanding the thread loop and guiding the thread loop around the spindle to form a lock stitch.
Working principle
The working principle of the rotary shuttle is usually that after the needle rises the distance, the shuttle tip of the rotary shuttle bed starts to hook into the wire ring, and the shuttle tip hooks the wire ring and continues to rotate. When the wire ring is sent to the guide rail mouth of the rotary shuttle frame, the wire ring is hooked by the partition hook of the shuttle frame. At this time, the needle should rise about 2mm from the lower position. The thread dividing hook on the shuttle frame should allow time for the end of the thread ring to move to the back of the guide rail when the thread ring is approaching. The movement axis angle between the thread dividing hook and the needle is about 50 °. The thread ring should be hooked at 45 ° on the convex surface of the outer frame of the shuttle tip of the shuttle bed and continue to rotate. The end of the thread ring should be hooked on the thread dividing hook. In order to make the surface of the thread ring smoothly, the oblique edge of the tail of the wire plate moves the thread end of the wire ring outward, while the rear of the wire ring, one side is hooked by the shuttle frame dividing hook and slides down to the bottom of the shuttle frame. At this moment, the needle exits in the shuttle mechanism.
Because the line passing place of the shuttle frame is very smooth, the wire loop slides out from the bottom of the shuttle frame smoothly. When the shuttle tip rotates 180 °, the wire pick-up lever rises to collect the remaining part of the wire sent down before the wire pick-up lever. The shuttle tip hooks the wire loop and continues to rotate. The front half of the wire loop is under the wire plate and passes through the 45 ° slope of the convex surface of the outer frame. The edge of the moving wire plate is gradually higher than the shuttle frame, pull the front half of the loop out of the way. The rear half of the wire loop is hooked by the shuttle frame splitting hook, and the wire loop is separated from the front and back. The front and back of the wire loop are sleeved over the shuttle frame, the bottom wire is sleeved in the middle, and the wire loop is tightened by the thread pick-up lever to form a stitch.
The operation cycle of the shuttle mechanism is between 203 ° and 312 °, which is the stage of hooking the wire loop and expanding the wire loop, and between 312 ° and 320 °, which is the stage of needle withdrawal from the socket notch and 0 ° to 180 °, which is the empty stroke. The upper shaft rotates once, the rotary shuttle rotates twice, and produces an effect when it rotates.
The principle of forming stitch by the rotary shuttle is basically the same as that of the pendulum shuttle, but its process and method of forming stitch are different from that of the pendulum shuttle: the rotary shuttle rotates at equal angular velocity, while the pendulum shuttle rotates at unequal velocity; In one up-and-down reciprocating motion of the needle (the main shaft rotates for one cycle), the rotary shuttle rotates for two cycles at the same angular velocity, while the rotary shuttle swings back and the rotary shuttle is fixed, the shuttle bed rotates. The thread ring is hooked by the tip of the shuttle bed, and the thread ring is divided by the hook of the shuttle frame, so that it bypasses the bobbin sleeve and the bottom and top of the shuttle frame, and is disconnected from the head of the shuttle plate to form a thread ring.