Roll material dispenser tear bar

Abstract

A web material dispenser tear bar, a dispenser assembly comprising a tear bar and a method of forming the same. The tear bar includes a cutting edge that is defined by a plurality of teeth that extend along a longitudinal edge of a body of the tear bar. The teeth include a first group of teeth that have a triangular shape defined by linear edges of the respective teeth and a second group of teeth where at least one side of each tooth of the second group of teeth have a curved edge that extends in a radial direction toward an adjacent one of the plurality of teeth. The tear bar is preferably disposed in the housing of a dispenser and oriented to engage a web material to selectively perforate and/or sever a portion of the web material from the roll.

What is claimed is: 
     
         1 . A tear bar for use in a web material dispenser, the tear bar comprising:
 a body that extends in a longitudinal direction between a first end and a second end of the body; and   a cutting edge that is defined by a plurality of teeth that extend along a longitudinal edge of the body, the plurality of teeth comprising:
 a first group of teeth that have a triangular shape relative to a direction normal to a plane of the body; and 
 a second group of teeth wherein at least one side of each tooth of the second group of teeth has a curved edge that extends in an outward radial direction toward an adjacent one of the plurality of teeth. 
   
     
     
         2 . The tear bar of  claim 1  wherein each tooth of the second group of teeth are adjacent to at least one other tooth of the second group of teeth such that the curved edge of a first one of the second group of teeth faces a curved edge of a second one of the second group of teeth. 
     
     
         3 . The tear bar of  claim 2  wherein, the curved edge of the first one of the second group of teeth and the curved edge of the second one of the second group of teeth are separated by an arcuate trough therebetween. 
     
     
         4 . The tear bar of  claim 3 , wherein the curved edge of the first one of the second group of teeth, the curved edge of the second one of the second group of teeth and the arcuate trough defines a first arcuate channel. 
     
     
         5 . The tear bar of  claim 4  wherein at least one tooth of the first group of teeth has a linear edge that is adjacent to a linear edge of at least one other tooth of the first group of teeth. 
     
     
         6 . The tear bar of  claim 5  wherein the linear edge of the at least one tooth of the first group of teeth intersects the linear edge of the at least one other tooth at an acute angle to define an acute channel. 
     
     
         7 . The tear bar of  claim 6  wherein the acute angle is less than 65°. 
     
     
         8 . The tear bar of  claim 7  further comprising a plurality of acute channels disposed between the first arcuate channel and a second arcuate channel. 
     
     
         9 . The tear bar of  claim 8  wherein the linear edge of the at least one tooth of the first group and the linear edge of the at least one other tooth at an acute angle are separated by a rectilinear trough. 
     
     
         10 . The tear bar of  claim 9  wherein the linear edge of the first one of the first group of teeth, the linear edge of the second one of the first group of teeth and the rectilinear trough defines a first gap channel. 
     
     
         11 . The tear bar of  claim 10  further comprising a plurality of acute channels disposed between the first arcuate channel and the first gap channel. 
     
     
         12 . A web material dispenser comprising:
 a housing defined by a cover that movably cooperates with a base;   a hub assembly disposed in the housing and oriented to support a roll of a web material;   a drive mechanism supported the housing and oriented to advance the roll of the web material;   a tear bar disposed in the housing and oriented to engage the web material to selectively perforate a portion of the web material from the roll;   a first set of teeth defined by a portion of an edge of the tear bar, each tooth of the first set of teeth having linear edges that intersect one another at an apex; and   a second set of teeth defined by another portion of the edge of the tear bar, each tooth of the second set of teeth having at least one arcuate edge having a radius of curvature that extends across an axis that extends in a lateral direction across the tear bar and is coincident with an apex of the tooth having the at least one arcuate edge.   
     
     
         13 . The web material dispenser of  claim 12  wherein each tooth of the second set of teeth further comprises a linear edge that is opposite the respective at least one arcuate edge. 
     
     
         14 . The web material dispenser of  claim 12  wherein each tooth of the second set of teeth are adjacent to at least one other tooth of the second set of teeth so the arcuate edge of a first one of the second set of teeth faces an arcuate edge of a second one of the second group of teeth and are separated by an arcuate trough. 
     
     
         15 . The web material dispenser of  claim 14  wherein the arcuate edge of the first one of the second set of teeth, the arcuate edge of the second one of the second set of teeth and the arcuate trough defines a first arcuate channel. 
     
     
         16 . The web material dispenser of  claim 15  wherein the linear edge of at least one tooth of the first set of teeth is adjacent to and intersects at an acute angle the linear edge of at least one other tooth of the first set of teeth to define an acute channel. 
     
     
         17 . The web material dispenser of  claim 16  further comprising a plurality of acute channels disposed between the first arcuate channel and a second arcuate channel. 
     
     
         18 . The web material dispenser of  claim 17  wherein the linear edge of at least one tooth of the first set of teeth and an adjacent linear edge of a second one of the first set of teeth extends outwardly from the tear bar and are separated by a rectilinear trough. 
     
     
         19 . The web material dispenser of  claim 18  wherein the linear edge of the at least tooth of the first set of teeth, the adjacent linear edge of the second one of the first set of teeth and the rectilinear trough defines a first gap channel. 
     
     
         20 . The web material dispenser of  claim 19  further comprising a plurality of acute channels disposed between the first arcuate channel and the first gap channel. 
     
     
         21 . A method of forming a perforation bar of a rolled web material dispenser, the method comprising:
 forming a cutting body defined by a thickness and a longitudinal length that extends between a first longitudinal end and a second longitudinal end of the body; and   forming a cutting edge with a longitudinal edge of the body and defining the cutting edge to include a first group of teeth that have a triangular shape relative to a direction normal to the thickness of the body and a second group of teeth wherein at least one side of each tooth of the second group of teeth has a curved edge that extends in an outward radial direction in a plane defined by the longitudinal length of the body toward an adjacent one of the plurality of teeth.   
     
     
         22 . The method of  claim 21  further comprising orienting an apex of each tooth of the first group of teeth to be collinear with an apex of each tooth of the second group of teeth.