Sealing arrangement

Abstract

A cone arm assembly comprises an arm having a shaft extending therefrom in which the shaft is angularly surrounded by a shoulder surface on one end thereof. A cone has a recess formed therein which receives the shaft in a manner to permit a rotation of the cone relative to the shaft about a rotational axis. The cone has a base surface facing the shoulder surface of the arm. A first seal element is positioned within the recess and forms a first seal between the shaft of the arm and the cone. A second seal element is positioned within the recess and forms a second seal between the shaft of the arm and the cone. The second seal is positioned closer to the shoulder surface than the first seal. A third seal element forms a third seal between the base surface of the cone and the shoulder surface of the arm.

We claim: 
     
         1 . A cone arm assembly comprising:
 an arm having a shaft extending therefrom in which the shaft is angularly surrounded by a shoulder surface on one end thereof;   a cone having a recess formed therein which receives the shaft in a manner to permit a rotation of the cone relative to the shaft about a rotational axis, the cone having a base surface facing the shoulder surface of the arm;   a first seal element positioned within the recess forming a first seal between the shaft of the arm and the cone;   a second seal element positioned within the recess forming a second seal between the shaft of the arm and the cone, the second seal being positioned closer to the shoulder surface than the first seal; and   a third seal element forming a third seal between the base surface of the cone and the shoulder surface of the arm.   
     
     
         2 . The cone arm assembly of  claim 1 , wherein a groove extends inward from the base surface, the third seal element being placed within the groove. 
     
     
         3 . The cone arm assembly of  claim 2 , wherein the groove comprises a first side wall, a second side wall, and a bottom wall, and the first side wall, the second side wall, and the bottom wall collectively extend circumferentially about the base surface. 
     
     
         4 . The cone arm assembly of  claim 2 , wherein the recess is formed of a first cylindrical section and a second cylindrical section, the first cylindrical section being defined by a first radius and extending inwardly away from the base surface, and the second cylindrical section defined by a second radius smaller than the first radius, the second cylindrical section extending away inwardly away from the first cylindrical section. 
     
     
         5 . The cone arm assembly of  claim 4 , wherein a first channel and a second channel are formed within the first cylindrical section, the first channel receiving a portion of the first seal element and the second channel receiving a portion of the second seal element. 
     
     
         6 . The cone arm assembly of  claim 5 , wherein the first channel and second channel each comprise an upper wall, a radial wall, and a lower wall. 
     
     
         7 . The cone arm assembly of  claim 6 , wherein the bottom wall of the groove, the upper wall of the first channel, and the upper wall of the second channel lie in approximately parallel planes. 
     
     
         8 . The cone arm assembly of  claim 6 , wherein the bottom wall of the groove is formed at a first depth from the base surface and the upper wall of the second channel is formed at a second depth from the base surface greater than the first depth. 
     
     
         9 . The cone arm assembly of  claim 6 , wherein the first side wall and second side wall are each positioned radially outward from the radial wall of the second channel. 
     
     
         10 . The cone arm assembly of  claim 4 , wherein a thrust washer is positioned on a step formed at the junction of the first cylindrical section and the second cylindrical section. 
     
     
         11 . The cone arm assembly of  claim 4 , wherein the first seal element is adhesively coupled to the first channel. 
     
     
         12 . The cone arm assembly of  claim 1 , wherein at least one bearing is coupled to the shaft, the at least one bearing being positioned distally away from the first seal element, the second seal element, and the third seal element. 
     
     
         13 . The cone arm assembly of  claim 1 , wherein the third seal element is positioned radially outward from the first seal element and the second seal element. 
     
     
         14 . The cone arm assembly of  claim 1 , wherein the first seal element, the second seal element, and third seal element are each positioned concentric with the rotational axis, but at different axial positions with respect to one another. 
     
     
         15 . The cone arm assembly of  claim 1 , wherein the third seal element has a Shore A hardness exceeding 60. 
     
     
         16 . The cone arm assembly of  claim 1 , wherein the third seal element comprises urethane. 
     
     
         17 . The cone arm assembly of  claim 1 , wherein a plurality of cutting carbides are coupled to an outer surface of the cone. 
     
     
         18 . The cone arm assembly of  claim 1 , wherein the base surface of the cone and the shoulder surface of the arm are spaced apart from one another by between about 0.038 cm and about 0.064 cm. 
     
     
         19 . The cone arm assembly of  claim 1 , wherein the second seal element is a PolyPak™ seal. 
     
     
         20 . The cone arm assembly of  claim 1 , wherein each of the first seal element, the second seal element, and the third seal element are comprised of an elastomeric material.