Tube cut off machine

An apparatus for cutting off predetermined lengths from a moving length of roll form material such as tubing adapted to be positioned downstream from a source comprising

• at least one cut-off assembly which is reciprocated longitudinally of the moving length of material and operated during the movement to sever a predetermined length,
• said cut-off assembly including a knife blade that is moved in an endless path to cut a length of tubing which is being moved,
• means for reciprocating said cut-off assembly such that the cutting occurs when the cut-off assembly is moving at a speed corresponding to the speed of movement of the tubing
• said means for reciprocating said cut-off assembly comprising a servo motor drive,
• means interconnecting said servo motor drive and said cut-off assembly including a servo motor crank drive assembly, including
• a servo motor
• a crank driven by said servo motor,
• a slot track,
• a cam follower on said crank engaging said slot track such that as the crank is rotated the cam follower is moved in a generally circular path,
• means yieldingly mounting said cam follower such that it is urged radially outwardly,
• said slot track having a flat tangential portion on at least one end of said slot track, such that the cam follower traverses a straight line and the cam follower is yieldingly urged radially inwardly by said flat portion during contact of the cam follower with the flat portion of the slot track,
• said servo motor crank drive assembly being connected to said cut-off assembly for moving said knife blade in said endless path such that during this movement the cam follower is in contact with the flat portion, the cut-off assembly moves at a uniform speed corresponding to the speed of movement of the tube at the time the length of tubing is being cut off,
• means for adjusting the machine to cut tubes of different lengths,
• said adjusting means comprising a differential beam pivot assembly wherein one end of the beam is driven in a linear reciprocating path by said crank and the other end of the beam is connected to reciprocate the cut-off assembly such that it is driven at a speed corresponding to the speed of the tube at the time the length of tubing is cut off.

An apparatus for cutting off predetermined lengths from a moving length of roll form material such as tubing adapted to be positioned downstream from a source comprising

• at least one cut-off assembly which is reciprocated longitudinally of the moving length of material and operated during the movement to sever a predetermined length,
• said cut-off assembly including a knife blade that is moved in an endless path to cut a length of tubing which is being moved such that the knife blade is moved in a straight line tangential to its axis and transverse to the path of the tubing when the knife blade intersects the path of the tubing to cut the tubing,
• means for reciprocating said cut-off assembly such that the cutting occurs when the cut-off assembly is moving at a speed corresponding to the speed of movement of the tubing,
• said means for reciprocating said cut-off assembly comprising a servo motor drive,
• means interconnecting said servo motor drive and said cut-off assembly including a servo motor crank drive assembly, including
• a servo motor,
• a crank driven by said servo motor,
• a slot track,
• a cam follower on said crank engaging said slot track such that as the crank is rotated the cam follower is moved in a generally circular path,
• means yieldingly mounting said cam follower such that it is urged radially outwardly,
• said slot track having a flat tangential portion on at least one end of said slot track, such that the cam follower traverses a straight line and the cam follower is yieldingly urged radially inwardly by said flat portion, during contact with the flat portion of the slot track,
• said servo motor crank drive assembly being connected to said cut-off assembly for moving said knife blade in said straight line of said endless path and during this movement the cam follower is in contact with the flat portion such that the cut-off assembly moves at a uniform speed corresponding to the speed of movement of the tube at the time the length of tubing is being cut off.