Adjustable seat track having improved track engagement structure

A seat adjustment apparatus comprising:

• a first rail having a plurality of complementary openings extending along the longitudinal axis, the complementary openings being defined by generally parallel spaced-apart surfaces;
• a second rail having a plurality of alternating openings and teeth having tapered spaced-apart surfaces that define the openings;
• and
• a locking mechanism having first and second locking portions, the first and second locking portions being selectively moveable between a released position where the first and second rails can move freely relative to one another along the longitudinal axis, and a locked position where the first and second locking portions include teeth extending into the selected openings and complementary openings in the first and second rails to maintain the first rail in a selected position relative to the second rail,
• the first and second locking portions being further configured for relative axial movement along the longitudinal axis as the locking mechanism is moved from the released position to the locked position such that at least one of the teeth of each of the first and second locking portions are engageable with at least one of the parallel spaced-apart surfaces of the first rail teeth and at least one of the generally tapered spaced-apart side surfaces of the second rail to attenuate longitudinal freeplay between the first and second rails.

A vehicle seat assembly comprising:

• a seat having a seat back and a seat bottom;
• a seat adjustment apparatus having a stationary rail configured to engage a portion of a vehicle, the stationary rail having a plurality of tapered teeth and a moveable rail connected to the seat bottom, the moveable rail having a plurality of openings defined by spaced-apart locking surfaces, the stationary and moveable rails being engaged for selective relative axial movement along a longitudinal axis;
• and
• a locking mechanism having a master plate that includes at least one drive tooth and at least one load tooth, the at least one drive tooth being configured to engage one of the tapered teeth and the spaced-apart locking surfaces and the at least one load tooth having a clearance relationship with at least one of the tapered teeth and the locking surfaces, and a slave plate having at least one drive tooth and at least one load tooth,
• the master and the slave plates being selectively moveable between a released position where the stationary and moveable rails can move freely relative to one another along the longitudinal axis, and a locked position where the master and slave plates maintain the moveable rail in a selected position relative to the stationary rail,
• the master and slave plates being further configured for relative axial movement along the longitudinal axis as the locking mechanism is moved from the released position to the locked position such that at least one of the teeth of each of the master and slave plates are engageable with at least one of the tapered teeth and the locking surfaces to attenuate longitudinal freeplay between the moveable and stationary rails.