Package film tension adjusting device of packaging machine

Abstract

A packaging machine includes a supply of a package film and a wrapping/sealing section into which products to be packaged are conveyed. A package film tension adjusting device is arranged between the supply of the package film and the wrapping/sealing section for routing the package film to the wrapping/sealing section and for adjusting the tension of the package film supplied to the wrapping/sealing section. The package film tension adjusting device includes a chassis inside which two rails are fixed. Two slide blocks are movably supported on the rails and are movable toward/away from the wrapping/sealing section along the rails. A conveyor is supported on the slide blocks for conveying the products into the wrapping/sealing section. Film routing members are attached to the conveyor for routing the package film toward the wrapping/sealing section. Moving the slide blocks along the rails causes the distance between the film routing members and the wrapping/sealing section to be changed thereby changing the tension of the package film supplied from the film routing members to the wrapping/sealing section in a stepless manner. A locker unit is mounted to at least one of the slide blocks for releasably securing the slide block at a desired position along the rails. A screw rod threadingly engages the slide blocks for moving the slide blocks along the rails.

What is claimed is:  
     
         1 . A package film tension adjusting device adapted to be mounted between a supply of a package film and a wrapping/sealing section of a packaging machine, the package film tension adjusting device comprising rails on which slide blocks are movably supported for being movable relative to the wrapping/sealing section and thus changing distance therebetween, film routing means being mounted on the slide blocks to be movable therewith, the package film being fed into the wrapping/sealing section by the film routing means whereby moving the slide blocks along the rails changes the distance between the film routing means and the wrapping/sealing section and thus tension of the package film supplied from the film routing means to the wrapping/sealing section.  
     
     
         2 . The package film tension adjusting device as claimed in  claim 1  further comprising stops arranged at opposite ends of the rails for limiting the movement of the slide blocks along the rails.  
     
     
         3 . The package film tension adjusting device as claimed in  claim 1  further comprising a locker unit associated with at least one of the slide blocks for releasably securing the slide blocks at a desired position along the rails.  
     
     
         4 . The package film tension adjusting device as claimed in  claim 3  wherein the locker unit comprises a collar slidably fit over one of the rails, an inner-threaded hole being defined in the collar for threadingly engaging a threaded section of a handle, the handle having an inner tip selectively engaging the rail for securing the slide block at the desired position along the rail.  
     
     
         5 . The package film tension adjusting device as claimed in  claim 1  further comprising bearing means mounted between the slide blocks and the rails.  
     
     
         6 . The package film tension adjusting device as claimed in  claim 1  further comprising a screw rod threadingly engaging inner-threaded holes defined in the slide blocks whereby rotation of the screw rod causes movement of the slide blocks along the rails.  
     
     
         7 . The package film tension adjusting device as claimed in  claim 6  further comprising a device for rotating the screw rod.  
     
     
         8 . The package film tension adjusting device as claimed in  claim 7 , wherein the device for rotating the screw rod comprises a hand wheel.  
     
     
         9 . The package film tension adjusting device as claimed in  claim 7 , wherein the device for rotating the screw rod comprises an electric motor.