Continuous motion drive mechanism for a form, fill, and seal machine

Abstract

The present invention provides a drive mechanism for a form, fill and seal machine for forming a tube out of a heat sealable sheet. The machine includes front and rear jaw assemblies arranged on opposite sides of the tube, which follow the movement of the tube during the sealing operation. The drive mechanism for each side of the jaw assemblies comprises a front drive gear and a real drive gear, which are driven in opposing directions. The front and rear drive gears are coupled to front and rear linkage bases, respectively, which in turn are coupled to the front and rear jaw assemblies, respectively, to cyclically bring the opposing jaw assemblies into contact to seal the tube. A slide bar may be disposed directly between the front and rear linkage bases, or alternatively, directly between the front and rear jaw assemblies, to help maintain the linkage bases and jaw assemblies in registry during their rotational cycles, thereby improving the sealing quality of the package being formed.

1 . A drive mechanism for a form, fill and seal machine for forming a tube out of a heat sealable sheet, of the type including first and second jaw assemblies arranged on opposite sides of the tube that follow the movement of the tube during the sealing operation, wherein the drive mechanism for each side of the jaw assemblies comprises:
 a first sealing jaw mechanism having a first jaw assembly, a first drive gear and a first linkage base, wherein the first linkage base is adapted to be coupled between the first drive gear and the first jaw assembly;   a second sealing jaw mechanism having a second jaw assembly, a second drive gear and a second linkage base, wherein the second linkage base is adapted to be coupled between the second drive gear and the second jaw assembly; and   at least one slide bar adapted to be disposed between the first and second sealing jaw mechanisms to keep the jaw mechanisms in registry.   
     
     
         2 . The drive mechanism of  claim 1  wherein the slide bar is adapted to be disposed between the first jaw assembly and the second jaw assembly. 
     
     
         3 . The drive mechanism of  claim 1  wherein the slide bar is adapted to be disposed between the first linkage base and the second linkage base. 
     
     
         4 . The drive mechanism of  claim 1  further comprising:
 a first linkage housing having a bore disposed therein; and   a second linkage housing having a bore disposed therein,   wherein the slide bar extends longitudinally through the bores of the first linkage housing and the second linkage housing.   
     
     
         5 . The drive mechanism of  claim 4  further comprising at least one bushing disposed in the first and second linkage housings, wherein the slide bar extends longitudinally through the bushings. 
     
     
         6 . The drive mechanism of  claim 1  further comprising:
 a first output shaft driven by the first drive gear;   a crank arm operably coupled between the first output shaft and the first linkage base, wherein rotation of the crank arm effects rotation of the first linkage base in the same direction as the first drive gear;   a second output shaft driven by the second drive gear; and   a crank arm operably coupled between the second output shaft and the second linkage base, wherein rotation of the crank arm effects rotation of the second linkage base in the same direction as the second drive gear.   
     
     
         7 . The drive mechanism of  claim 1  further comprising:
 a first parallel link having upper and lower regions; and   a second parallel link having upper and lower regions,   wherein the lower regions of the first and second parallel links are operably coupled to the first linkage base, and the upper regions of the first and second parallel links are operably coupled to the first jaw assembly.   
     
     
         8 . The drive mechanism of  claim 7  further comprising:
 a third parallel link having upper and lower regions; and   a fourth parallel link having upper and lower regions,   wherein the lower regions of the third and fourth parallel links are operably coupled to the second linkage base, and the upper regions of the third and fourth parallel links are operably coupled to the second jaw assembly.   
     
     
         9 . A drive mechanism for a form, fill and seal machine for forming a tube out of a heat sealable sheet, of the type including first and second jaw assemblies arranged on opposite sides of the tube that follow the movement of the tube during the sealing operation, wherein the drive mechanism for each side of the jaw assemblies comprises:
 the first and the second jaw assemblies;   a first drive gear rotatable in a first driven direction and a second drive gear rotatable in a second driven direction opposite the first driven direction;   a first linkage base operably coupled between the first drive gear and the first jaw assembly;   a second linkage base operably coupled between the second drive gear and the second jaw assembly; and   at least one slide bar adapted to be disposed between the first and second jaw assemblies.   
     
     
         10 . The drive mechanism of  claim 9  wherein the first and second jaw assemblies each comprise bores formed therein, the slide bar being longitudinally disposed through the bores in the first and second jaw assemblies. 
     
     
         11 . The drive mechanism of  claim 10  further comprising at least one bushing disposed in the bores of the first and second jaw assemblies, wherein the slide bar extends longitudinally through the bushings. 
     
     
         12 . The drive mechanism of  claim 9  further comprising:
 a vertical rod; and   a slidable bracket attached to a portion of the slide bar, wherein the slidable bracket is disposed for vertical movement along the vertical rod.   
     
     
         13 . The drive mechanism of  claim 9  further comprising:
 a gear case located on one side of the tube;   an input drive shaft for the gear case; and   a driver gear journaled inthe gear case and carried by the input drive shaft, wherein the driver gear drives rotation of the second drive gear, which in turn drives rotation of the first drive gear.   
     
     
         14 . The drive mechanism of  claim 9  further comprising:
 a first output shaft driven by the first drive gear;   a crank arm operably coupled between the first output shaft and the first linkage base, wherein rotation of the crank arm effects rotation of the first linkage base in the same direction as the first drive gear;   a second output shaft driven by the second drive gear; and   a crank arm operably coupled between the second output shaft and the second linkage base, wherein rotation of the crank arm effects rotation of the second linkage base in the same direction as the second drive gear.   
     
     
         15 . The drive mechanism of  claim 9  further comprising:
 a first parallel link having upper and lower regions; and   a second parallel link having upper and lower regions,   wherein the lower regions of the first and second parallel links are operably coupled to the first linkage base, and the upper regions of the first and second parallel links are operably coupled to the first jaw assembly.   
     
     
         16 . The drive mechanism of  claim 15  further comprising:
 a third parallel link having upper and lower regions; and   a fourth parallel link having upper and lower regions,   wherein the lower regions of the third and fourth parallel links are operably coupled to the second linkage base, and the upper regions of the third and fourth parallel links are operably coupled to the second jaw assembly.   
     
     
         17 - 23 . (canceled)