Patent ID: 6325309
Filing Date: 2001-12-04
Classification: B02C

Abstract:
A gear protection device of a paper shredder, the device dividing gear box of the paper shredder into a first driving set and a second driving set, between which sets are featured with an auto-tripping transmission component to allow automatic, tripping effect when the feedback resistance of shredded paper exceeds an acceptable setting such that a gearbox and a blade assembly are temporarily free from driving force of a motor when the motor is still in operation, the gearbox including a primary gear driven by a small gear of an output shaft of the motor, and a secondary gear driven by the primary gear and transmitting the driving force to the blade assembly of the paper shredder, between which gears are featured with the auto-tripping device that trips in response to over-resistance, characterized in that, the device including a radial awl teethed face provided on an end face of the primary gear, a spring, an end bearing, and an end base provided on another end face of the primary gear such that tension of the spring after compression is exerted on the end face of the primary gear; the radial awl teethed face couples to a radial awl teethed face formed on an end face of the secondary gear so as to allow driving or tripping effect, the secondary gear being provided with a transmission gear on another end face thereof; the primary gear and the secondary gear are both serially connected on a central shaft such that the driving force from the output shaft of the motor, under normal operation, is transmitted through the small gear, the primary gear, and the radial awl teethed face to drive the radial awl teethed face of the secondary gear, which driving force is then transmitted through the transmission gear provided on another end of the secondary gear and other gear mechanisms to the blade wheel of the paper shredder, whereby when the resistance exerted by the blade wheel exceeds the acceptable setting so as to overwhelm the gearbox and the motor, the resistance of the blade wheel increases the counter transmission resistance of the second driving set of the secondary gear to exceed the output force of the first driving set and to exceed the static tension of the spring, such that resilience of the spring causes the radial awl teethed face that originally meshes with the radial awl teethed face between the primary and secondary gears to detach from the radial awl teethed face one tooth by one tooth, thereby ceasing rotation of the gears and the blade assembly subsequent to the secondary gear due to external resistance.