Bag Opening Apparatus for Filling Vertically Positioned Horizontally Traversing Plastic Film Bags

Abstract

In an automated machine that forms a vertically positioned and horizontally traversing web of plastic film into bags and fills the bags with material, the apparatus opens the bags by separating the bag upper longitudinal edge portions. First and second opposing slide gates on opposite sides of the bags normal traversing plane are moveable between closed and open positions. Longitudinal channels on each of the slide gates receive and clampingly grip the bag longitudinal edge portions when the gates are moved away from their closed positions. The bag edge portions are thereby gripped and separated from one another when the gates are opened for thereby opening and filling the bags. While opening the gates, additional longitudinal edge portions are pulled into the apparatus and, while closing the gates, the additional edge portions are pulled out therefrom. The longitudinal edge portions freely traverse through the channels when the gates are closed.

What is claimed is: 
     
         1 . A apparatus for opening and filling vertically positioned plastic film bags traversing horizontally along a normal traversing plane from an upstream location to a downstream location wherein said bags include a pair of parallel proximate longitudinal edge portions defining a bag opening therebetween leading to a bag cavity vertically therebelow, said apparatus comprising:
 a first gate on one side of said normal traversing plane selectively moveable between a closed position adjacent said normal traversing plane and an open position at a distance away from said normal traversing plane;   a second gate on the other side of said normal traversing plane opposing said first gate and selectively moveable between a closed position adjacent said normal traversing plane and an open position at a distance away from said normal traversing plane;   wherein each said first and second gates include a longitudinal channel receiving one of said bag longitudinal edge portions therethough;   wherein said longitudinal channels allow said bag edge portions to traverse therethrough when said gates are in their closed position and clampingly grip said bag edge portions when said gates are away from their closed position; and,   wherein, when said gates are in their open positions, said bag longitudinal portions are gripped and separated from one another for thereby opening and filling the bag and, when said gates are in their closed positions, said bag longitudinal portions are released and allowed to longitudinally traverse through their respective longitudinal channel.   
     
     
         2 . The apparatus of  claim 1  wherein each said longitudinal channel is formed between a leading gate plate and a selectively moveable clamp bar, said clamp bar being moveable away from said leading gate plate when said gate is in its closed position thereby opening said longitudinal channel and allowing said bag edge portion to traverse therethrough, and being moveable against said leading gate plate when said gate is away from its closed position thereby closing said longitudinal channel and clampingly griping said bag edge portion therebetween. 
     
     
         3 . The apparatus of  claim 2  wherein one or more springs move said clamp bar against said leading gate plate when said gate is away from its closed position. 
     
     
         4 . The apparatus of  claim 3  wherein a pneumatic cylinder is coupled to each of said first and second gates and wherein said pneumatic cylinders are selectively actuable for moving said gates to their closed and open positions. 
     
     
         5 . The apparatus of  claim 1  wherein, while said gates are being moved from their closed positions to their open positions, additional longitudinal edge portions are pulled into the apparatus from at least one of said upstream and downstream locations and, while said gates are being moved from their open positions to their closed positions, said additional longitudinal edge portions are pulled out of said apparatus towards at least one of said upstream and downstream locations. 
     
     
         6 . The apparatus of  claim 5  wherein a dancer bar assembly is provided at said upstream location and provides tension is said longitudinal edge portions and pulls said additional edge portions out of said apparatus while said gates are being closed. 
     
     
         7 . The apparatus of  claim 5  wherein a gripping and pulling assembly is provided at said downstream location and pulls said additional edge portions out of said apparatus while said gates are being closed. 
     
     
         8 . The apparatus of  claim 5  wherein said additional longitudinal portions at said upstream location extend through a pair of upstream clamping members and said additional longitudinal portions at said downstream location extend through a pair of downstream clamping members and wherein, while said gates are in their closed positions, said upstream and downstream clamping members allow said additional longitudinal portions to traverse therethrough and, while said gates are in their open positions, said upstream and downstream clamping members clampingly grip and prevent said additional longitudinal portions o traverse therethrough. 
     
     
         9 . The apparatus of  claim 8  wherein said clamping members are rubber rollers and wherein, while said gates are opening and closing, said rollers guide said additional longitudinal edges as they traverse therethrough. 
     
     
         10 . The apparatus of  claim 5  wherein each said longitudinal channel is formed between a leading gate plate and a selectively moveable clamp bar, said clamp bar being moveable away from said leading gate plate when said gate is in its closed position thereby opening said longitudinal channel and allowing said bag edge portion to traverse therethrough, and being moveable against said leading gate plate when said gate is away from its closed position thereby closing said longitudinal channel and clampingly griping said bag edge portion therebetween. 
     
     
         11 . The apparatus of  claim 10  wherein one or more springs move said clamp bar against said leading gate plate when said gate is away from its closed position. 
     
     
         12 . The apparatus of  claim 11  wherein a pneumatic cylinder is coupled to each of said first and second gates and wherein said pneumatic cylinders are selectively actuable for moving said gates to their closed and open positions. 
     
     
         13 . The apparatus of  claim 10  wherein a dancer bar assembly is provided at said upstream location and provides tension is said longitudinal edge portions and pulls said additional edge portions out of said apparatus while said gates are being closed. 
     
     
         14 . The apparatus of  claim 10  wherein a gripping and pulling assembly is provided at said downstream location and pulls said additional edge portions out of said apparatus while said gates are being closed. 
     
     
         15 . The apparatus of  claim 10  wherein said additional longitudinal portions at said upstream location extend through a pair of upstream clamping members and said additional longitudinal portions at said downstream location extend through a pair of downstream clamping members and wherein, while said gates are in their closed positions, said upstream and downstream clamping members allow said additional longitudinal portions to traverse therethrough and, while said gates are in their open positions, said upstream and downstream clamping members clampingly grip and prevent said additional longitudinal portions to traverse therethrough. 
     
     
         16 . The apparatus of  claim 15  wherein said clamping members are rubber rollers and wherein, while said gates are opening and closing, said rollers guide said additional longitudinal edges as they traverse therethrough. 
     
     
         17 . The apparatus of  claim 10  further comprising a bulk material measuring apparatus and wherein, when said gates are in their open positions, a quantity of bulk material is delivered between the gates, through the bag opening and into the hag cavity. 
     
     
         18 . The apparatus of  claim 10  wherein said plastic film bags are formed from a web of plastic film is folded along a central longitudinal fold line thereby defining said pair of parallel proximate longitudinal edge portions. 
     
     
         19 . The apparatus of  claim 1  further comprising a bulk material measuring apparatus and wherein, when said gates are in their open positions, a quantity of hulk material is delivered between the gates, through the bag opening and into the bag cavity. 
     
     
         20 . The apparatus of  claim 1  wherein said plastic film bags are formed from a web of plastic film is folded along a central longitudinal fold line thereby defining said pair of parallel proximate longitudinal edge portions.