Patent ID: 6896623

Claim:
An axially collapsible shaft assembly, comprising: a first shaft having an end; a second shaft having an end, wherein said second shaft has a hollow interior space defined by an interior wall; and an axially collapsible drive connection between said first shaft and said second shaft, said axially collapsible drive connection transmitting torque between said first shaft and said second shaft, said axially collapsible drive connection comprising: an end cap fixedly attached to said end of said second shaft, said end cap having a periphery, an annular score being formed in said end cap adjacent said periphery, said score having a bottom; and said end of said first shaft being fixedly attached to said end cap; wherein said first shaft is axially movable with respect to said second shaft in response to a force above a predetermined threshold value being applied axially to said first shaft and said second shaft, wherein the force breaks said bottom of said score and thereby creates a score periphery of said end cap which permits said first shaft and a central portion of said end cap to be telescopically received into said interior space of said second shaft; and wherein during the axial movement of said first shaft with respect to said second shaft in which said first shaft is telescopically received into said second shaft, said score periphery of said end cap scrapes said interior wall of said second shaft, wherein the scraping dissipates enemy as said first shaft is telescopically received into said second shaft.