Spring trip mechanism

A device for connection to an earth working tool comprising:

• a housing having a slot therein;
• means for connecting said housing to a tool bar;
• a tool holding rod being disposed in said slot, said rod having an earth working tool connected to the bottom end thereof;
• at least one lever pivotally connected to said housing, said lever being pivotally attached to said rod;
• and
• means for biasing said tool holding rod to a first position whereby when said earth working tool encounters an object it cannot penetrate, the tool holding rod and thereby the earth working tool moves rearwardly and upwardly with respect to the housing, said biasing means comprising:
• a bracket connected to said housing and having an opening therein;
• a shaft, said shaft having a first end and a second end, said shaft extending through said bracket and being pivotally connected to said tool holding rod at a point above the housing, a plate connected to the second end of the shaft and a compression spring being disposed around said shaft, one end of said compression spring being adjacent to said bracket and the other end thereof being adjacent to said plate.