Plunge slitter with clam style anvil rollers

In an apparatus for slitting a running paperboard web, said apparatus including a thin annular rotary cutting blade positioned with its axis of rotation over the web and having a peripheral cutting edge defined by opposite blade faces extending downwardly through the path of the web to slit the web in the direction of web travel, and an anvil roll assembly under the web including a pair of anvil rollers positioned to support the web at the point of the slit, said rollers defining therebetween a slot for receiving the blade edge therein, the improvement comprising:

• a lower support arrangement for said anvil rollers including a mounting bracket for each roller, a pivot joint joining the brackets for hinged movement to permit the slot to be opened to receive the blade edge and closed to cause the anvil rollers to bear against the opposite blade faces;
• a first actuator interconnecting the brackets, spaced from the pivot joint and operable to open and close said slot;
• and
• an upper support structure for said cutting blade including a blade drive and a blade support head mounted for generally vertical movement between an upper inoperative position with the blade out of engagement with the web and the anvil rollers and a lower operative position with the blade in slitting engagement with the web and with the blade edge extending into the slot;
• and, a second actuator interconnecting the support structure and the blade support head operable to move the blade support head between the upper and lower positions.