Packaging machine and associated film gripper

Abstract

A packaging machine for use in packaging a product using rolled wrap film includes a packaging station where film is to be manipulated during a packaging operation, a support for holding rolled film and located to permit film to be drawn into the packaging station and a film grip assembly for gripping at least one edge of film during at least part of a packaging operation. The film grip assembly includes a first jaw element, a second jaw element mounted for movement between a gripping position and a non-gripping position relative to the first jaw element and at least one pneumatic actuator positioned at least partially between the first jaw element and the second jaw element for selectively moving the second jaw element.

1 . A packaging machine for use in packaging a product using rolled wrap film, the machine comprising: 
 a packaging station where film is to be manipulated during a packaging operation;    a support for holding rolled film, the support located to permit film to be drawn into the packaging station;    a film grip assembly for gripping at least one edge of film during at least part of a packaging operation, the film grip assembly including: 
 a first jaw element;  
 a second jaw element mounted for movement between a gripping position and a non-gripping position relative to the first jaw element; and  
 at least one pneumatic actuator positioned at least partially between the first jaw element and the second jaw element for selectively moving the second jaw element.  
   
   
   
       2 . The machine of  claim 1  wherein the pneumatic actuator comprises a cylinder with an axial length of less than about 1.5 inches.  
   
   
       3 . The machine of  claim 2  wherein the cylinder is rigidly connected to the first jaw element, and a piston is movably positioned within the cylinder.  
   
   
       4 . The machine of  claim 3  wherein the axial length of the cylinder is less than about 1.0 inch.  
   
   
       5 . The machine of  claim 3  wherein the first jaw element includes a recessed surface portion receiving an end of the cylinder.  
   
   
       6 . The machine of  claim 2  wherein an entirety of the cylinder is positioned between the first jaw element and the second jaw element.  
   
   
       7 . The machine of  claim 1  wherein the film grip assembly further includes: 
 a third jaw element and a fourth jaw element positioned at respective sides of the second jaw element, both the third jaw element and the fourth jaw element mounted for movement between respective gripping and non-gripping positions relative to the first jaw element; and    at least one pneumatic actuator positioned between the first jaw element and the third jaw element for selectively moving the third jaw element;    at least one pneumatic actuator positioned between the first jaw element and the fourth jaw element for selectively moving the fourth jaw element; and    the pneumatic actuator between the first jaw element and the second jaw element is controllable separately from both the pneumatic actuator between the first jaw element and the third jaw element and the pneumatic actuator between the first jaw element and the fourth jaw element.    
   
   
       8 . The machine of  claim 1  wherein the second jaw element is mounted for pivotal movement between the gripping and non-gripping position, the pneumatic actuator contacts the second jaw element to one side of its pivot axis.  
   
   
       9 . The machine of  claim 1  wherein the second jaw element is biased into the non-gripping position, and the pneumatic actuator is operable in a push arrangement with the second jaw element and works against the bias when actuated.  
   
   
       10 . The machine of  claim 1  wherein the pneumatic actuator is operable in a push-pull arrangement with the second jaw element.  
   
   
       11 . A package wrapping machine for wrapping packages using rolled wrap film, the machine comprising: 
 a wrap station where wrap film is to be wrapped around a product;    a support for holding rolled wrap film, the support located to permit wrap film to be drawn into the wrap station;    a film grip assembly for gripping at least one edge of wrap film as it is drawn into the wrap station, the film grip assembly movable in a film draw direction and including: 
 a first jaw element;  
 a second jaw element mounted for pivotal movement between a gripping position and a non-gripping position relative to the first jaw element, the second jaw element biased into the non-gripping position;  
 and at least one pneumatic actuator positioned between the first jaw element and the second jaw element for selectively causing the second jaw element to pivot into the gripping position.  
   
   
   
       12 . The machine of  claim 11  wherein one of the first jaw element and the second jaw element is an upper jaw element, the other of the first jaw element and the second jaw element is a lower jaw element, and the pneumatic actuator has an actuation axis that is substantially vertical.  
   
   
       13 . The machine of  claim 11  wherein the pneumatic actuator comprises a cylinder arranged between the first jaw element and the second jaw element, a piston within the cylinder and movable along an actuation axis of the actuator, a sealing arrangement between the piston and the cylinder, wherein a high pressure side of the cylinder is positioned against a portion of the first jaw element.  
   
   
       14 . The machine of  claim 13  wherein the piston includes a nose portion that extends through an opening in an actuation side of the cylinder for contacting the second jaw element.  
   
   
       15 . The machine of  claim 13  wherein the portion of the first jaw element is a recessed portion that receives an end of the cylinder.  
   
   
       16 . The machine of  claim 13  wherein the sealing arrangement comprises at least one o-ring disposed between the piston and the cylinder.  
   
   
       17 . The machine of  claim 16  wherein the o-ring has a triangular cross-section, with one corner in contact with an inner surface of the cylinder.  
   
   
       18 . The machine of  claim 13  wherein the sealing arrangement comprises a flexible membrane.  
   
   
       19 . The machine of  claim 13  wherein the cylinder has a length of less than about 1.0 inch.  
   
   
       20 . The machine of  claim 13  wherein the portion of the first jaw element includes an opening therein for receiving pressurized air to cause the piston to move away from the first jaw element.  
   
   
       21 . The machine of  claim 11  wherein the pneumatic actuator comprises a cylinder with an axial length of less than about 1.5 inches.  
   
   
       22 . The machine of  claim 21  wherein an entirety of the cylinder is positioned between the first jaw element and the second jaw element and the cylinder is rigidly connected to the first jaw element, a piston is movably positioned within the cylinder.  
   
   
       23 . The machine of  claim 11  wherein a mount bracket is located between the first jaw element and the second jaw element, a pivot rod is supported by the mount bracket and defines a pivot axis of the second jaw element.  
   
   
       24 . In a package wrapping machine for wrapping packages using rolled wrap film, a method for selectively gripping rolled wrap film using a film gripper including a first jaw element and a second jaw element, the second jaw element movable between a gripping position and a non-gripping position relative to the first jaw element, the method comprising: 
 utilizing a pneumatic actuator positioned between the first jaw element and the second jaw element to selectively control whether the second jaw element is in the gripping position, including controlling delivery of pressurized fluid to the pneumatic actuator.    
   
   
       25 . The method of  claim 24  wherein the second jaw element is biased into the non-gripping position and the pneumatic actuator works against the bias.  
   
   
       26 . The method of  claim 24  wherein the second jaw element is mounted for a pivotal movement and the pneumatic actuator is positioned to one side of a pivot axis of the second jaw element to effect pivoting of the second jaw element.