Spring biased inertial latch for vehicle seat assemblies

An inertial latching mechanism for use in a vehicle seat assembly having a seatback member pivotally movable with respect to a seat member, wherein said latching mechanism is used to secure said seatback member against pivotal movement relative to said seat member in a first direction when a vehicle in which said seat assembly is mounted undergoes acceleration in a generally opposite second direction greater than a design threshold acceleration value, said latching mechanism comprising:

• first and second hinged members pivotally mounted about a common first pivot with said first hinged member having a first gear rack arranged thereon, wherein one of said first and second hinged members is mounted on one of said seat and seatback members and the other of said first and second hinged members is mounted on the other of said seat and seatback members;
• a pawl means having an engaging portion adapted for latching engagement with said gear rack, said pawl means being mounted on said second hinged member for movement between a first latched position whereat said pawl means engages said gear rack to secure said first hinged member as aforesaid, a second transitional position, and a third unlatched position whereat said pawl means is disengaged from said gear rack;
• a spring means interconnected at all times between said second hinged member and said pawl means so as to retain said pawl means in said third unlatched position until said vehicle undergoes acceleration in said second direction above said design threshold value, above which value the resultant inertial forces of the combination of the pawl means and the spring means overcomes said retention, thereby to cause relative movement of said pawl means in said first direction past said second transitional position, beyond which second transitional position said spring means is interconnected as aforesaid to bias said pawl means toward said first latched position and to hold said pawl means in said first latched position.

In a vehicle seat assembly having a seatback member pivotally movable with respect to a seat member, an inertial latching mechanism to secure said seatback member against pivotal movement relative to said seat member in a first direction when a vehicle in which said seat assembly is mounted undergoes acceleration in a generally opposite second direction greater than a design threshold acceleration value, said latching mechanism comprising:

• first and second hinged members pivotally mounted about a common first pivot with said first hinged member having a first gear rack arranged thereon, wherein one of said first and second hinged members is mounted on one of said seat and seatback members and the other of said first and second hinged members is mounted on the other of said seat and seatback members;
• a pawl means having an engaging portion adapted for latching engagement with said gear rack, said pawl means being mounted on said second hinged member for movement between a first latched position whereat said pawl means engages said gear rack to secure said first hinged member as aforesaid, a second transitional position, and a third unlatched position whereat said pawl means is disengaged from said gear rack;
• a spring means interconnected at all times between said second hinged member and said pawl means so as to retain said pawl means in said third unlatched position until said vehicle undergoes acceleration in said second direction above said design threshold value, above which value the inertial forces of the pawl means overcome said retention, thereby to cause relative movement of said pawl means in said first direction past said second transitional position, beyond which second transitional position said spring means is interconnected as aforesaid to bias said pawl means toward said first latched position and to hold said pawl means in said first latched position.