Mechanical Warp Stop Motion

The warp stop motion is an auxiliary loom motion. It is an extra part of the loom with a crucial purpose: to stop the loom right away when a thread breaks during weaving. This feature is essential for improving fabric quality and making the loom more efficient. If a thread breaks and the loom keeps running, the broken end can get stuck behind the heald wire’s eye, causing issues. So, the warp stop motion prevents this problem and ensures smooth weaving.

Working Principle:

In the loom, there are several connected parts: the cam lever and eccentric, which are linked by a connecting rod. When the eccentric rotates, it makes the cam lever move back and forth (oscillate).

The cam lever is connected to the fulcrum lever in the middle, and at the top of the fulcrum lever, there’s a forked bracket attached. So, when the cam lever moves back and forth, the forked bracket also moves accordingly. As a result, the reciprocating bar, connected to the forked bracket, also moves back and forth.

Under normal operation, the drop wire rests on the warp end due to the tension in the warp. There’s enough space between the top edge of the reciprocating bar and the drop wire slot, allowing the reciprocating bar to move freely between two fixed outer bars. In this situation, the release catch trip lever remains in a stable position, and the loom continues running smoothly.

However, if the warp end breaks, the drop wire falls into the cut-out of the reciprocating bar, creating an obstacle that hinders the back-and-forth movement of the reciprocating bar. As a result, the spring-loaded end of the fulcrum lever rises because it can’t move sideways.

With the rise of the fulcrum lever, the release catch trip lever also rises. This allows the outside end of the release catch trip lever to fall, and it releases the lifting catch. The lifting catch then slides over the outside end of the cam lever.

As the cam lever’s end rises, it lifts the lifting catch, which, in turn, raises the knock-off lever through a wire. This action brings another catch attached to the sley (part of the loom) into line with a projection on the starting handle unit. This causes the loom to be “knocked off,” meaning it stops the loom’s operation.

In summary, when the warp end breaks, a series of interconnected movements occur, triggering the loom to stop and prevent any damage or issues in the weaving process.

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