Apparatus for the cutting of columns of thread loops

An apparatus for the manufacture of a pile fabric by severing thread loops disposed parallel to one another in successive columns along one surface of a fabric web, said apparatus comprising:

• means forming a cutting station and defining a cutting location;
• means for relatively displacing said station and said web to advance the thread loops of each column successively to said location and displace the respective column past said location;
• a guide needle engaged in the column of thread loops advanced toward said location and supporting each thread loop at said location;
• a laser mounted at said station;
• a focusing lens movably disposed at said station for focusing a beam from said laser on said location;
• means coupling said needle to said lens and maintaining the zone of focus in said beam upon each loop disposed on said needle at said location, said needle being provided with a hook portion at said location defining an abutment engageable by each thread loop and an inclined flank accelerating the following thread loops toward a thread loop positioned against said abutment whereby the thread loops at said locations are substantially in contact with one another and said beam impinges upon the successive thread loops substantially without encountering said needle, said needle being mounted on a slider;
• spring means resiliently bearing on said slider against the force exerted thereon by movement of said thread loops along said needle, said slider being formed as a cam engageable by a cam follower, said slider being connected to an arm normally latched to retain said needle in its operative position, said cam follower releasing said arm upon operation by said cam, said cam follower being provided on a lever;
• and
• electromagnetic means responsive to the reflection of light from said needle and the absence of a thread loop at said location for displacing said lever to unlatch said arm.