THE WEFT FORK STOP MOTION.
FIG. 69.
One of the most useful adjuncts to the power-loom is the motion for stopping the loom when the weft breaks or runs out. [Fig. 69] will explain the principle of this useful contrivance. The grid A is placed at the side of the reed between the reed and the shuttle-box, and the fork is so placed that as the grid moves forward the prongs of the fork pass through it. When the weft comes between the fork and the grid it raises the end of the fork E, out of the way of the hammer H, which is moved forward every two picks by a cam or lifter, D, on the bottom shaft of the loom. If the weft breaks or runs out the fork will of course pass through the grid, and it is so balanced that the hook E will be caught by the hammer and the loom handle knocked off. The invention of the Weft Fork Stopping Motion is claimed by several persons, but it was perfected about the year 1842, when the brake was applied to it. The action of this brake is illustrated at [Fig. 70]. When the handle is pushed sideways in starting the loom it lifts the rod R and the lever L, and thus takes the brake off. When the handle is knocked off by the weft fork being caught, the lever L drops and the brake is applied. The brake power can be regulated by altering the position of the weight on the levers.
FIG. 70.
In looms with change boxes at both sides the weft fork is often placed in the middle of the loom. It is obvious that when several shuttles are used there will always be some weft threads opposite the grid in the ordinary weft fork motion, and this renders it inoperative in this class of looms. It is therefore necessary to have a fork to feel for each pick separately.