Parking brake system

A parking brake system comprising:

• a parking brake lever which is capable of being pulled up so as to drag a brake cable, and is swingably pivotally supported on a bracket which is connected to a vehicle body, the parking brake lever comprising a base portion which is pivotally supported on the bracket by a pivot connection, and a grip portion extending upwardly from the base portion;
• a ratchet pawl pivotally supported on the parking brake lever via a fulcrum pin, the ratchet pawl having a spring engagement portion at a first end thereof, and a locking claw at a second end thereof, wherein a predetermined clearance is provided between the ratchet pawl and the fulcrum pin;
• a ratchet plate affixed to the bracket, and including a plurality of locking teeth and a plurality of locking grooves arranged alternately, wherein the locking claw of the ratchet pawl is capable of engaging with the locking teeth and the locking grooves;
• a release rod configured to press the ratchet pawl in accordance with an occupant's release operation to make the ratchet pawl swing in a direction in which the locking claw is disengaged from the locking grooves;
• and
• a torsion spring mounted on a boss on the base portion of the parking brake lever, the torsion spring having a first end operatively connected to a lower end portion of the release rod, and a second end operatively connected to the spring engagement portion of the ratchet pawl;
• wherein a direction of a first straight line and a direction of a second straight line are set different from each other, the first straight line representing a straight line on which a point of contact between the ratchet pawl and the release rod, a center of an arc of one of the locking teeth and a center of an arc of the locking claw exist while a tip of the locking tooth and a tip of the locking claw are in contact with each other, the second straight line representing a straight line on which a point of contact between the fulcrum pin and the ratchet pawl, the center of the arc of the locking tooth, and the center of the arc of the locking claw exist while the tip of the locking tooth and the tip of the locking claw are in contact with each other,
• wherein when the release rod is disengaged, the locking claw moves from a position where the first straight line is established, toward a position where the locking claw is engaged with the locking groove while the ratchet pawl moves by said predetermined clearance,
• and wherein each of the locking teeth includes a respective tip end portion having an arcuate outline shape defining a respective tooth tip radial center point, and the ratchet claw includes a tip end portion formed in an arcuate outline shape defining a claw tip radial center point, to promote sliding movement of the ratchet claw in relation to a tooth tip during operation of the parking brake system.