Cutting device of packaging machine

Abstract

A cutting device is incorporated in a packaging machine having at least one expansion cylinder consisting of upper and lower sections with a gap therebetween. The cutting device includes two rails located on opposite sides of the expansion cylinder and substantially parallel to each other. Two slide blocks are respectively and movably mounted on the rails for movement along the rails between first and second positions on opposite sides of the expansion cylinder. A single cutting blade is arranged between and carried by the slide blocks whereby when the slide blocks are moved along the rails between the first and second positions, the blade is driven to reciprocally pass through the gap between the upper and lower sections of the expansion cylinder. A driving device mechanically coupled to at least one of the slide blocks drives the slide blocks and the cutting blade to move linearly along the corresponding rails between the first and second positions and thus causing the cutting blade to reciprocally pass through the gap for cutting off a packaging material supplied to the expansion cylinder.

What is claimed is  
     
         1 . A cutting device adapted to be incorporated in a packaging machine having an expansion cylinder consisting of upper and lower sections with a gap therebetween, the cutting device comprising: 
 two rails located on opposite sides of the expansion cylinder and substantially parallel to each other;    a slide block movably mounted on each of the rails whereby the slide block is movable between first and second positions on opposite sides of the expansion cylinder;    a cutting blade arranged between and carried by the slide blocks whereby when the slide blocks are moved along the rails between the first and second positions, the blade is driven to pass through the gap between the upper and lower sections of the expansion cylinder; and    a driving device mechanically coupled to at least one of the slide blocks for driving the slide block to move in a linear path along the corresponding rail between the first and second positions and thus causing the cutting blade to reciprocally pass through the gap for cutting off a packaging material supplied to the expansion cylinder.    
     
     
         2 . The cutting device as claimed in  claim 1  further comprising at least two sensors positioned on opposite sides of the expansion cylinder along the rails.  
     
     
         3 . The cutting device as claimed in  claim 1 , wherein the cutting blade has sharp front and rear ends.  
     
     
         4 . The cutting device as claimed in  claim 1 , wherein the driving device comprises a motor to which a link arm is coupled in an offset fashion whereby when the motor is actuated, the link arm is driven to move in an eccentric fashion.  
     
     
         5 . The cutting device as claimed in  claim 4 , wherein a disk is concentrically mounted to the motor, a radially-extending slot being defined in the disk, the link arm having a first end to which a rotation joint is formed, the rotation joint being coupled to the disk by a rod extending through and releasably secured to the slot of the disk, the rod being selectively movable along the disk to adjust the eccentricity of the rod with respect to the motor.  
     
     
         6 . The cutting device as claimed in  claim 5 , wherein the link arm has a second end to which a rotation joint is formed for rotatably coupling to the slide block.  
     
     
         7 . The cutting device as claimed in  claim 1 , wherein the driving device comprises at least a power cylinder coupled to at least one of the slide blocks.  
     
     
         8 . The cutting device as claimed in  claim 7 , wherein the power cylinder comprises a hydraulic cylinder.  
     
     
         9 . The cutting device as claimed in  claim 7 , wherein the power cylinder comprises a pneumatic cylinder.  
     
     
         10 . The cutting device as claimed in  claim 1 , wherein the driving device comprises a motor having a first spindle, a second spindle spaced from and substantially parallel to and first spindle and a belt coupling between the spindles, an attachment mounted to the belt to be movable therewith, the attachment being connected to one of the slide blocks for driving the slide block to move along the rails.