Electric pencil sharpener

An electric pencil sharpener, comprising:

• a power device connected to two rotatable rubber wheels via a transmission mechanism;
• the two rubber wheels, which are located on two sides of a pencil to be sharpened, have opposite rotational directions and closely fit a side wall of the pencil to be sharpened to push the pencil upwards or downwards to be sharpened, a gap between the two rubber wheels being adjustable;
• and
• a rotatable cutter carrier assembly which is located below the rubber wheels and configured to sharpen the pencil to be sharpened,
• wherein the transmission mechanism comprises:
• a cutter carrier gear connected to the power device and located below the rubber wheels, a rotation axis of the cutter carrier gear being perpendicular to a rotation axis of each of the rubber wheels;
• an end face gear engaged with the cutter carrier gear, a rotation axis of the end face gear being in parallel with the rotation axis of each of the rubber wheels;
• a transition gear located at an outer side of the end face gear and engaged with the end face gear, a rotation axis of the transition gear being in parallel with the rotation axis of the end face gear and located below the rotation axis of the end face gear;
• and
• a pencil introducing gear located at an upper side of the transition gear and engaged with the transition gear, wherein
• a pencil introducing gear shaft of the pencil introducing gear is moved coaxially with a rubber wheel shaft sleeve of the rubber wheels, and two pencil introducing gear shafts are both arranged onto a pencil introducing mechanism holder having a fixed relative position, two sides of the pencil introducing mechanism holder have arc-shaped retaining grooves configured to restrict movement loci of the respective pencil introducing gear shafts, the arcs of the two arc-shaped retaining grooves are coincident with movement loci of two pencil introducing gears with respect to the transition gear respectively to adjust the gap between the two rubber wheels,
• the electric pencil sharpener further comprises a multipoint control unit (MCU), a first switch, a second switch, a first driving circuit and a second driving circuit, wherein
• the first switch is arranged below the pencil to be sharpened, a tip touch block is provided between the first switch and a tip of the pencil to be sharpened, and when the pencil to be sharpened is delivered to the cutter carrier assembly by the rubber wheels and is sharpened by the cutter carrier assembly, the tip touches the tip touch block, and the first switch is turned on by a transmission rod;
• the second switch is located at an entrance position of the pencil to be sharpened, and when the pencil to be sharpened is inserted between the two rubber wheels, a pencil introducing switch pressing block located at a movement locus of the pencil to be sharpened is pressed to an outer side of the pencil to be sharpened, to turn on the second switch;
• the first switch and the second switch are respectively connected to two input pins of the MCU;
• a first terminal of the first driving circuit and a first terminal of the second driving circuit are connected to two output pins of the MCU respectively, and a second terminal of the first driving circuit is connected to a first end of the power device, a second terminal of the second driving circuit is connected to a second end of the power device, the second terminal of the first driving circuit is connected to the second terminal of the second driving circuit;
• a first ground electrode and a first voltage electrode are also connected between the first terminal of the first driving circuit and the second terminal of the first driving circuit, and a second ground electrode and a second voltage electrode are also connected between the first terminal of the second driving circuit and the second terminal of the second driving circuit;
• and
• when the first switch and the second switch are both turned off, the power device does not work, when the first switch is turned off and the second switch is turned on, the power device rotates toward a direction of transferring the pencil to be sharpened to the cutter carrier assembly, and when the first switch and the second switch are both turned on, the power device rotates toward a direction of moving the pencil to be sharpened away from the cutter carrier assembly.