Twisted tuft end brush and method of making

Abstract

A twisted knot tuft wire filament end or cup brush suitable for carbon removal on engine blocks, for example, activates a longer useful service life by utilizing a center core formed into the center of the brush and conforming to and embracing the inner ends of the twisted tuft knots as they project from the cup. The core is applied in a putty-like condition and preferably with axial pressure. The core cures into a solid though somewhat elastic plug embracing the individual knots at the center of the brush and confining them against the cup wall. The invention substantially reduces fracture and particularly long fracture of the wire filaments significantly increasing brush life.

1 . A twisted tuft knot type end brush having a cup, an annular row of twisted knot tufts projecting from the cup, and a center plug shaped to conform to and embrace the twisted knot tufts within the cup.  
     
     
         2 . An end brush as set forth in  claim 1 , wherein said center plug is a core of non-metallic material embracing the interior of the knots within the cup and having a tensile shear strength of from about 600 to about 1200 psi.  
     
     
         3 . An end brush as set forth in  claim 2 , wherein said material has a tensile shear strength of from about 800 to about 1000 psi.  
     
     
         4 . An end brush as set forth in  claim 1 , wherein said center plug is a core of non-metallic material embracing the knots within the cup and having a hardness of from about 60 to about 90 on the Shore D scale.  
     
     
         5 . An end brush as set forth in  claim 4 , wherein said material has a hardness of from about 70 to about 80 on the Shore D scale.  
     
     
         6 . An end brush as set forth in  claim 1 , wherein said center plug is a core of non-metallic material embracing the interior of the knots within the cup and having a modulus of elasticity of about 6×10 5 , and which will maintain its stability to about 300° F.  
     
     
         7 . An end brush as set forth in  claim 1 , wherein said center plug is a core of non-metallic material formed of epoxy resin.  
     
     
         8 . An end brush as set forth in  claim 7  including a knot retainer plate secured in the bottom of the cup and having alternating fingers and notches, said core being applied in putty or liquid form and flowing between said notches to embrace said knots.  
     
     
         9 . An end brush as set forth in  claim 8 , wherein each finger includes an upturned radius bend, and a wrap-around hole in said bend, each knot including a loop extending through said hole in a plane radially of the cup, said notches enabling core access to the loop.  
     
     
         10 . A twisted wire tuft end brush comprising a cup having a bottom, a retainer secured to said bottom, said retainer including equally spaced projecting fingers with notches there between, each finger being bent to extend axially of the cup, a hole in the bottom of each of the bent fingers, a twisted knot tuft looped through each hole and extending axially of the cup.  
     
     
         11 . A brush as set forth in  claim 10 , wherein said fingers are bent 90° through a radius of curvature, said hole extending throughout said radius.  
     
     
         12 . An end brush as set forth in  claim 10 , including a non-metallic core in the center of the brush embracing the knots within the cup.  
     
     
         13 . An end brush as set forth in  claim 12 , wherein said core has a tensile shear strength of from about 600 to about 1200 psi, and a hardness on the Shore D scale of about 60 to about 90.  
     
     
         14 . An end brush as set forth in  claim 13 , wherein said core has a modulus of elasticity of about 6×10 5 , and will maintain its stability at about 300° F.  
     
     
         15 . A method of making a twisted knot wire tuft end brush comprising the steps of arranging and securing an annular row of twisted knot tufts projecting from a cup, and placing a center plug within the row of tufts to conform to and form a core embracing the twisted knot tufts within the cup.  
     
     
         16 . A method as set forth in  claim 15  including the step of retaining the twisted knot tufts with a retaining disk having alternating fingers and notches, each finger being bent axially of the cup with a radius bend, each bend having a wrap around hole through which the wire tuft extends to be twisted to form the knot.  
     
     
         17 . A method as set forth in  claim 16  including the step of forming a loop through the hole at the inner end of the knot.  
     
     
         18 . A method as set forth in  claim 17  including the step of placing the center plug in liquid or putty form to extend through the notches to embrace the knots.  
     
     
         19 . A method as set forth in  claim 15  including the step of placing the plug in putty form, and pressing on the putty to cause it to conform to the knots.  
     
     
         20 . A method as set forth in  claim 15  including the step of placing the plug in liquid form, and flowing said plug to embrace the knots.  
     
     
         21 . A method as set forth in  claim 15 , wherein said plug solidifies to form a core having a tensile shear strength of from about 600 to about 1200 psi, and a hardness on the Shore D scale of from about 60 to about 90.  
     
     
         22 . A method as set forth in  claim 21 , wherein said core has a modulus of elasticity of about 6×10 5  and which will maintain its stability to about 300° F.