Film Tension Apparatus And Supply Roll Support For Stretch Wrapping Machines

Abstract

A film dispenser for stretch wrapping machines includes at least one roller and a first brake engageable with a braking surface the one roller. The first brake may include a flat brake pad that is pivotally movable for engagement with the braking surface, and is adjustable between a first configuration engaged with the braking surface and applying a first braking force, and a second configuration disengaged from the braking surface or only minimally engaged with the braking surface such that any braking force applied is substantially less than the first braking force.

What is claimed is: 
     
         1 . A film dispenser for stretch wrapping machines, comprising:
 at least one roller, the roller having a longitudinal axis and a circumferential film engaging surface;   a braking surface extending circumferentially around the roller relative to the circumferential film engaging surface; and   an electrically-actuated first brake engageable with either a portion of a sector of the braking surface or a portion of an area defined by an arc along the braking surface of the at least one roller, the first brake selectively adjustable between a first configuration engaged with the braking surface and applying a first braking force to the braking surface, and a second configuration wherein the first brake is disengaged from the braking surface or is only minimally engaged such that any braking force applied is substantially less than the first braking force.   
     
     
         2 . The film dispenser of  claim 1 , further comprising:
 a disk coupled with a first axial end of the at least one roller, the disk having first and second oppositely disposed sides;   wherein the braking surface is located on circumferentially extending portions of the first and second sides of the disk.   
     
     
         3 . The film dispenser of  claim 2 , wherein the first brake comprises a first brake pad adjacent the first side of the disk and a second brake pad adjacent the second side of the disk, such that the disk is disposed between the first and second brake pads;
 at least one of the first and second brake pads movable between the first and second configurations of the first brake along directions substantially parallel to an axial direction of the disk.   
     
     
         4 . The film dispenser of  claim 2 , wherein the first brake is selectively adjustable to vary the amount of first braking force applied to the braking surface. 
     
     
         5 . The film dispenser of  claim 3 , wherein the first brake comprises an actuator operatively coupled with the first brake pad, the actuator selectively actuatable to at least a first condition wherein the first and second brake pads engage the braking surface in the first configuration of the first brake, and wherein the first braking force stretches the film material during wrapping of a load. 
     
     
         6 . The film dispenser of  claim 5 , wherein the actuator is actuatable to a second condition wherein the first and second brake pads engage the braking surface in the first configuration of the first brake, and wherein the first brake applies a second braking force that prevents free rolling of the roller while allowing the roller to rotate to facilitate threading of film through the dispenser. 
     
     
         7 . The film dispenser of  claim 6 , wherein the actuator is actuatable to a third condition wherein the first and second brake pads engage the braking surface in the first configuration of the first brake, and wherein the first brake applies a third braking force that locks the roller against rotation. 
     
     
         8 . The film dispenser of  claim 7 , wherein the actuator is actuatable to a fourth condition wherein at least the first brake pad is disengaged from the braking surface in the second configuration of the first brake. 
     
     
         9 . The film dispenser of  claim 5 , further comprising:
 a first brake arm pivotally movable about a first pivot axis that is substantially perpendicular to the axial direction of the disk;   the first brake pad supported on the first brake arm for pivotal movement about the first pivot axis into engagement with the braking surface.   
     
     
         10 . The film dispenser of  claim 9 , further comprising:
 a second brake arm pivotally movable about a second pivot axis that is substantially perpendicular to the axial direction of the disk;   the second brake pad supported on the second brake arm for pivotal movement about the second pivot axis into engagement with the braking surface.   
     
     
         11 . The film dispenser of  claim 10 , wherein the roller is resiliently supported for movement in a direction along the longitudinal axis of the roller and biased in a direction toward the disk to compensate for the weight of the roller. 
     
     
         12 . The film dispenser of  claim 1 , wherein the first brake comprises a solenoid actuator having an armature operatively coupled with a first brake pad, the armature moving the first brake pad to engage the braking surface in the first configuration of the first brake. 
     
     
         13 . The film dispenser of  claim 12 , wherein the solenoid actuator is selectively actuatable to at least a first condition wherein the first brake pad engages the braking surface in the first configuration of the first brake, and wherein the first braking force stretches the film material during wrapping of a load. 
     
     
         14 . The film dispenser of  claim 13 , wherein the solenoid actuator is actuatable to a second condition wherein the first brake pad engages the braking surface in the first configuration of the first brake, and wherein the first brake applies a second braking force that prevents free rolling of the roller while allowing the roller to rotate to facilitate threading of film through the dispenser. 
     
     
         15 . The film dispenser of  claim 14 , wherein the solenoid actuator is actuatable to a third condition wherein the first brake pad engages the braking surface in the first configuration of the first brake, and wherein the first brake applies a third braking force that locks the roller against rotation. 
     
     
         16 . The film dispenser of  claim 15 , wherein the solenoid actuator is actuatable to a fourth condition wherein the first brake pad is disengaged from the braking surface in the second configuration of the first brake. 
     
     
         17 . A film dispenser for stretch wrapping machines, comprising:
 at least one roller, the roller having a circumferential film engaging surface and a circumferential braking surface;   a brake arm pivotally movable about a pivot axis spaced from the roller;   a brake pad supported on the brake arm for pivotal movement with the brake arm about the pivot axis into engagement with the braking surface along a substantially radial direction of the roller; and   an actuator operatively engaging the brake arm at a location spaced from the pivot axis and the brake pad, whereby braking force applied by the brake pad when the actuator is actuated is increased by leverage of the brake arm about the pivot axis.   
     
     
         18 . The film dispenser of  claim 17 , wherein the actuator selectively actuatable to at least one of:
 a first condition wherein the brake pad engages the braking surface with a first braking force that stretches the film material during wrapping of a load.   a second condition wherein the brake pad engages the braking surface with a second braking force that prevents free rolling of the roller while allowing the roller to rotate to facilitate threading of film through the dispenser;   a third condition wherein the brake pad engages the braking surface with a third braking force that locks the roller against rotation; or   a fourth condition wherein the brake pad is disengaged from the braking surface.   
     
     
         19 . A method of dispensing stretch wrap material to a load, the method comprising:
 feeding film from a supply roll;   engaging the film from the supply roll with at least one roller;   selectively engaging the roller with a first brake; and   engaging the roller with a second brake.   
     
     
         20 . The method of  claim 19 , further comprising applying at least one of:
 a first braking force to the roller with the first brake such that the film is stretched as it is applied to wrap the load;   a second braking force to the roller with the second brake, the second braking force preventing prevent free rolling of the roller while allowing the roller to rotate sufficiently to facilitate threading film from the supply roll to the roller when the first brake is not engaged; or   a third braking force to the roller with the first brake such that the roller is locked against rotation.