Ground following snow plow attachment

Abstract

A trigger assembly for attaching a snow plow blade to a vehicle is described. The trigger assembly consists in a combination of a nesting arm and a nested arm rotatable around one another, wherein the arms are furthermore coupled through a biasing means. The trigger assembly is adapted for reacting when the ground-contacting edge of the snow plow blade hitting an obstacle in the nested arm rotating out of the nesting arm and the biasing means being extended.

1 - 20 . (canceled) 
     
     
         21 . A trigger assembly for attaching a snow plow blade having a ground-contacting edge to a vehicle, the trigger assembly comprising:
 a pivot axis located higher than the ground-contacting edge of the snow plow blade;   a nesting arm adapted to be coupled to the vehicle, the nesting arm comprising a top extremity and a bottom extremity, the nesting arm being rotatably coupled to the pivot axis about its bottom extremity, the nesting arm comprising an extension plate extending about its bottom extremity farther to the top extremity than the pivot axis;   a nested arm adapted to couple the snow plow blade thereto, the nested arm comprising a top extremity and a bottom extremity, the nested arm being rotatably coupled to the pivot axis about its bottom extremity, the nested arm being adapted to nest at least partially in the nesting arm, the nested arm comprising a pin member extending away to the nesting arm about its top extremity; and   biasing means coupling the pin member to the extension plate, the biasing means being extendable between a short length and a long length, the biasing means being biased toward restoring to its short length,   wherein, when the ground-contacting edge hits an obstacle, the obstacle generates a torque over the snow plow blade resulting in the nested arm rotating out of the nesting arm and the biasing means being extended.   
     
     
         22 . The trigger assembly of  claim 21 , wherein the pin member consists in a pair of pin members extending opposite to one another. 
     
     
         23 . The trigger assembly of  claim 21 , wherein the biasing means consists in a pair of springs. 
     
     
         24 . The trigger assembly of  claim 23 , wherein the springs are coil springs. 
     
     
         25 . The trigger assembly of  claim 21 , wherein the nesting arm is adapted to be non-rotatably coupled to the vehicle. 
     
     
         26 . The trigger assembly of  claim 21 , wherein the snow plow blade is coupled to the nested arm above the pivot axis. 
     
     
         27 . The trigger assembly of  claim 21 , where the biasing means extend along the nesting arm outside the nesting arm. 
     
     
         28 . The trigger assembly of  claim 21 , wherein the nesting arm comprises a pair of neighbor plates with a void in-between adapted to nest at least partially the nested arm. 
     
     
         29 . The trigger assembly of  claim 28 , wherein the nesting arm comprises a coupling section about the top extremity coupling the neighbor plates. 
     
     
         30 . The trigger assembly of  claim 21 , wherein the pin member is rotatable around a pin axis parallel to the pivot axis. 
     
     
         31 . The trigger assembly of  claim 21 , wherein the nested arm comprises an end-of-course section about its top extremity abutting the nesting arm, the end-of-course section of the nested arm limiting nesting of the nested arm in the nesting arm. 
     
     
         32 . The trigger assembly of  claim 21 , wherein the nesting arm comprises a body extending between its top extremity and its bottom extremity, wherein the extension plate is rotatably mounted to the body, and wherein the extension plate abutting against the body limits rotation of the extension plate towards the nested arm. 
     
     
         33 . The trigger assembly of  claim 21 , comprising a pivoting attachment point providing the pivot axis. 
     
     
         34 . The trigger assembly of  claim 33 , wherein the pivoting attachment point is provided through a bolt extending across the nesting arm and the nested arm. 
     
     
         35 . The trigger assembly of  claim 21 , wherein an eyebolt is mounted to the pin member, wherein the biasing means is hooked to the eyebolt. 
     
     
         36 . The trigger assembly of  claim 35 , wherein sensibility of the trigger assembly can be modified by screwing or unscrewing the eyebolt over the pin member to modify extension of the biasing means when the nested arm is nested in the nesting arm. 
     
     
         37 . A snow plow blade adapted to be coupled to a vehicle through a first one and a second one of the trigger assemblies of  claim 31 . 
     
     
         38 . The snow plow blade of  claim 37 , wherein the pivot axis of the first trigger assembly and the pivot axis of the second trigger assembly are co-axial. 
     
     
         39 . The snow plow blade of  claim 37 , wherein the trigger assemblies mounted rearward to the snow plow blade.