Foil feeder for sealing unit of blister-packaging machine

Abstract

A cover-foil strip is pressed by a sealing roller over blisters of a blister-foil strip passing over a pocket roller having an array of pockets corresponding generally to the blisters. A drive rotates the rollers to draw the strips in a transport direction. A sensor capable of detecting the blisters thereof is connected to a controller also connected to the drive for adjusting a rotation rate of the rollers in accordance with the detected positions of the blisters relative to the rollers. A pair of grippers upstream in the direction from the rollers are each engageable in a closed position with a respective edge of the blister-foil strip. A second drive connected with the grippers can shift the grippers between the closed positions and open positions and can reciprocate the grippers in the transport direction when in the closed positions for advancement of the blister-foil strip in the direction.

1 . An apparatus for sealing a cover-foil strip over blisters of a blister-foil strip, the apparatus comprising: 
 a roller having an array of pockets corresponding generally to the blisters, the blister-foil strip passing over the roller with the blisters fitting in the pockets;    a sealing roller juxtaposed with the pocket roller and pressing the cover-foil strip against the blister-foil strip on the pocket roller;    first drive means for rotating the rollers and drawing the strips between the rollers in a transport direction;    a sensor juxtaposed with the blister-foil strip adjacent the rollers and capable of detecting the blisters thereof;    control means connected between the drive means and the sensors for adjusting a rotation rate of the rollers in accordance with the detected positions of the blisters relative to the rollers;    a pair of grippers upstream in the direction from the rollers and each engageable in a closed position with a respective edge of the blister-foil strip; and    second drive means connected with the grippers and with the control means for shifting the grippers between the closed positions and open positions disengaged from the respective edges and for reciprocating the grippers in the transport direction when in the closed positions for advancement of the blister-foil strip in the direction.    
     
     
         2 . The sealing apparatus defined in  claim 1  wherein the second drive means includes: 
 a motor having a rotatable output shaft;    first and second eccentrics carried on the shaft;    respective first and second links carried on the eccentrics and shifted in the transport direction on rotation of the shaft;    a support shiftable in the direction, connected to the first link, and carrying the grippers, whereby rotation of the output shaft shifts the support in the direction; and    respective cams coupled to the second link and operatively engaged with the grippers for shifting same between the open and closed positions.    
     
     
         3 . The sealing apparatus defined in  claim 2  wherein the support is a rotatable support shaft having ends carrying the cams, the drive means further comprising: 
 a crank extending radially from the support shaft and connected to second link, whereby rotation of the output shaft pivots the support shaft and the cams.    
     
     
         4 . The sealing apparatus defined in  claim 3  wherein each gripper includes a lower jaw in which a respective one of the ends of the support shaft is journaled and an upper jaw shiftable vertically relative to the lower jaw and operable by the respective cam.  
     
     
         5 . The sealing apparatus defined in  claim 1  wherein the pockets of the pocket roller are spaced apart at a spacing that is slightly larger than a spacing between the blisters of the blister strip.  
     
     
         6 . The sealing apparatus defined in  claim 5  wherein the pockets are larger than the blisters.  
     
     
         7 . The sealing apparatus defined in  claim 1  wherein the control means synchronizes the roller rotation only when the grippers are in the closed position.  
     
     
         8 . The sealing apparatus defined in  claim 1  wherein each of the grippers includes an upper jaw and a lower jaw, the apparatus further comprising 
 a linear guide supporting one of the jaws of each of the grippers for displacement only in the transport direction.