Quick-release headband ratchet mechanism

A headband ratchet mechanism for tightening/loosening a headband of a safety helmet, comprising:

• a housing having open opposite first and second ends and configured to receive opposite end portions of the headband into an interior of the housing;
• a pinion gear having a plurality of gear teeth being disposed in the interior of the housing, the pinion gear being rotatable about an axis of rotation in a tightening direction and an opposite loosening direction;
• a pinion gear drive for driving the pinion gear in the tightening and opposite loosening directions, the pinion gear drive comprising ratchet gear, the knob being disposed on the axis of rotation and being rotatable about the axis of rotation in the tightening and loosening directions, the knob being accessible to a user to rotate the knob to tighten or loosen the headband, the ratchet gear being disposed on the axis of rotation between the knob and the pinion gear, the ratchet gear comprising a body being rotatable about the axis of rotation in the tightening and loosening directions and being normally non-rotatably connected to both the knob and the pinion gear;
• a ratchet mechanism comprising a ring gear, at least one pawl arm extending radially from the body of the ratchet gear, and a torque transmission member b being disposed between the ratchet gear and the knob on the axis of rotation, the torque transmission member being normally non-rotatably connected to the knob and conjointly rotatable with the knob, the torque transmission member comprising at least one drive member, each individual drive member of the at least one drive member being associated with a respective individual pawl arm of the at least one pawl arm;
• the ring gear normally surrounding the ratchet gear, the ring gear being coaxial with the ratchet gear with respect to the axis of rotation, the ring gear being fixed with respect to the axis of rotation and comprising a plurality of radially extending teeth wherein each tooth has a steep tooth angle on a first side thereof and a less-steep tooth angle on a second side thereof;
• each individual pawl arm of the at least one pawl arm being a resilient member extending away from the ratchet gear body to a free end portion of the individual pawl arm, the resiliency of the individual pawl arm urging the free end portion of the individual pawl arm to face towards the steep side of a tooth of the ring gear while the ratchet gear is stationary with respect to the axis of rotation, the steep sides of the plurality of teeth of the ring gear being disposed to engage against the free end portion of the individual pawl arm and resist and prevent rotation of the ratchet gear in the loosening direction in response to a force applied to the pinion gear teeth urging rotation of the pinion gear in the loosening direction;
• each individual drive member of the at least one drive member of the torque transmission member being disposed to extend parallel with the axis of rotation to the ratchet gear, the individual drive member being disposed between the ratchet gear body and the pawl arm associated with the individual drive member, the individual drive member being disposed to engage against a first portion of the associated pawl arm when the torque transmission member rotates in the tightening direction that urges the ratchet gear to rotate in the tightening direction whereby the associated pawl arm slides over the less-steep sides of the plurality of ring gear teeth during rotation of the ratchet gear in the tightening direction, and being disposed to engage against a second portion of the associated pawl arm when the knob is rotating in the loosening direction that urges the associated pawl arm away from engagement with the ring gear teeth whereby the associated pawl arm does not prevent rotation of the body in the loosening direction;
• and
• a release mechanism for selectively disconnecting the knob from the pinion gear comprising an actuator, a spring, and the torque transmission member comprising a plurality of teeth facing the knob, the knob comprising a plurality of teeth facing the torque transmission member, the torque transmission member being relatively axially movable with respect to the knob towards and away from the knob between a first position wherein the torque transmission member teeth are meshed with the knob teeth wherein the meshed teeth non-rotatably connect the torque transmission member with the knob and a second position wherein the torque transmission member teeth are spaced apart from and are not meshed with the knob teeth, the spring being disposed to generate a spring force applied to the torque transmission member urging the torque transmission member to the first position, the spring being elastically deformable in response to the torque transmission member moving between first and second positions to generate spring force at both of the first and second positions of the torque transmission member, the actuator being at least partially disposed in a knob bore and being axially movable with respect to the knob, the actuator capable of being pushed by a user to displace the torque transmission member from the first position to the second position whereby the torque transmission member and the pinion gear are both rotatably released from the knob and can rotate independently of the knob.