An automatic short pen retracting device and a pencil sharpener to which the same is applied

Abstract

The present invention discloses an automatic short pen retracting device and a pencil sharpener to which the same is applied. The automatic short pen retracting device includes a triggering mechanism, a shifting gear, a forward rotation gear, and a reverse rotation gear. When retracting the short pen, the shifting gear is driven by the triggering mechanism to switch from being engaged with the forward rotation gear to being engaged with the reverse rotation gear. The present invention provides an automatic short pen retracting device, which reduces the application of controller components and the cost of the automatic pencil sharpener by providing a triggering mechanism and a shifting gear and using the above mechanical structure to replace the short pen retracting control circuit in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of pencil sharpeners, and more particularly to an automatic short pencil ejection device and an automatic pencil sharpener to which the same is applied. Background Art

[0002] An automatic pencil sharpener is a new type of stationery that integrates the functions of pencil sharpening and automatic pen feeding and retracting. Its working method is that when a pencil is inserted into the pen insertion hole, the pen body triggers a start contact at the opening of the pen insertion hole, and the start contact is used to trigger a micro switch to connect the circuit, and the motor starts to work and drives the tool holder to rotate automatically through a reduction gear set, thereby starting automatic pencil sharpening.

[0003] In actual use, due to the short length of the pencil, the situation of a short pencil 'getting stuck' in the pen insertion hole may occur. To solve this problem, the existing solution is to add a short pencil retraction control circuit in the automatic pencil sharpener. When the micro switch is closed, the short pencil retraction control circuit will work automatically to complete the retraction of the short pencil. However, this solution requires adding corresponding controller components, increasing the production cost of the automatic pencil sharpener. Summary of the Invention

[0004] The present invention aims to solve one of the technical problems in the related art to a certain extent. For this purpose, the present invention provides an automatic short pencil ejection device, which reduces the application of controller components and the cost of the automatic pencil sharpener by setting a trigger mechanism and a shift gear and using the above mechanical structure to replace the short pencil retraction control circuit in the prior art.

[0005] The present invention also provides an automatic pencil sharpener to which the above automatic short pencil ejection device is applied.

[0006] The technical solution adopted by the present invention is: to provide an automatic short pencil ejection device, including a trigger mechanism, a shift gear, a forward rotation gear and a reverse rotation gear, and the shift gear is driven by the trigger mechanism to switch from being engaged with the forward rotation gear to being engaged with the reverse rotation gear.

[0007] In the above structure, when a short pencil enters, the tail of the pencil triggers the trigger mechanism, and the shift gear returns to the position engaged with the reverse rotation gear to start the automatic pencil ejection operation, and the short pencil is directly ejected through the automatic pencil ejection operation. In the present invention, by adjusting the position of the transmission gear through the trigger mechanism, the short pencil retraction control circuit in the prior art is replaced, reducing the application of controller components and the cost of the automatic pencil sharpener.

[0008] According to an embodiment of the present invention, the triggering mechanism includes a starting contact and a pen - inserting triggering component. When the short pen moves downward to the lower part of the pen - inserting triggering component and the starting contact is in the position of connecting to the power supply, the shifting gear switches from being engaged with the forward - rotation gear to being engaged with the reverse - rotation gear; when inserting the pen, the pen body triggers the pen - inserting triggering component, causing it to move the shifting gear to the position engaged with the forward - rotation gear. When the short pen enters, the pen tail first disengages from the pen - inserting triggering component, while the starting contact still contacts the pen body, and the circuit of the automatic pencil sharpener remains in the on - state. The shifting gear switches from being engaged with the forward - rotation gear to being engaged with the reverse - rotation gear, and the rotation direction changes.

[0009] According to an embodiment of the present invention, it further includes a transmission rod drivingly connected to the forward - and - backward pen - moving component. The shifting gear is slidably fitted with the transmission rod in a torque - transmissible manner, or the shifting gear is fixedly installed on the transmission rod; when the power is turned on, the torque of the forward - rotation gear or the torque of the reverse - rotation gear can be transmitted through the shifting gear and the transmission rod to the forward - and - backward pen - moving component, causing the forward - and - backward pen - moving component to perform the forward / backward pen - moving operation. The shifting gear reciprocates axially along the transmission rod, causing the shifting gear to switch back and forth between the positions engaged with the forward - rotation gear and the reverse - rotation gear, achieving the purpose of adjusting the rotation direction of the forward - and - backward pen - moving component.

[0010] According to an embodiment of the present invention, the triggering mechanism further includes a fork rod. When inserting the pen, the pen - inserting triggering component pushes the shifting gear to move through the fork rod; so that the shifting gear switches back and forth between the position engaged with the forward - rotation gear and the position engaged with the reverse - rotation gear.

[0011] According to an embodiment of the present invention, when inserting the pen, the pen - inserting triggering component pushes the transmission rod to drive the shifting gear to move.

[0012] According to an embodiment of the present invention, the pen - inserting triggering component includes a pair of parallel swing rods, and the triggering parts on the swing rods swing in the vertical direction following the self - rotation of the swing rods.

[0013] According to an embodiment of the present invention, the swing rods are provided with clamping parts, and a clamping gap is formed between the clamping parts.

[0014] An automatic pencil sharpener includes the automatic short - pen withdrawing device described in any one of the above. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following - described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 Stereogram of the automatic short pen retracting device in the initial state in the present invention;

[0017] Figure 2 Stereogram of the automatic short pen retracting device in the pen - feeding state in the present invention;

[0018] Figure 3 Structural schematic diagram of the automatic short pen retracting device in the pen - feeding state in the present invention;

[0019] Figure 4 is Figure 3 Local enlarged view of part A in

[0020] Figure 5 Stereogram of the automatic short pen retracting device in the present invention;

[0021] Figure 6 Structural schematic diagram of the automatic short pen retracting device after being inverted in the present invention;

[0022] Figure 7 Structural diagram of the automatic short pen retracting device in the pen - feeding state in the present invention;

[0023] Figure 8 Structural schematic diagram of the fork lever in the present invention;

[0024] Figure 9 Structural schematic diagram of the main body of the automatic pencil sharpener in the present invention;

[0025] Figure 10 Bottom view of the upper cover in the present invention;

[0026] Figure 11 Stereogram of the automatic pencil sharpener in the present invention.

[0027] Explanation of the reference numerals in the figure:

[0028] 1. Fork lever; 2. Transmission rod; 3. Shift gear; 4. Forward rotation gear; 5. Reverse rotation gear; 6. Starting contact; 7. Upper cover; 8. Pen feeding and retracting assembly; 9. Support platform; 10. Trigger rod; 11. Swing rod; 12. First elastic member; 13. Second elastic member; 14. Micro - switch; 15. Driving shaft; 16. Link; 17. Motor; 18. First delay gear; 19. Second delay gear;

[0029] 1a. Pen - feeding surface; 1b. Delay surface; 1c. Pen - retracting surface;

[0030] 11a. Clamping part; 11b. Meshing part; 11c. Trigger part. Detailed implementation manners

[0031] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0032] In this embodiment, the start contact 6 is arranged at the position of the pen inlet hole. When the pencil enters the pen, the pen body triggers the start contact 6 to turn on the circuit in the automatic pencil sharpener. Figure 3 and Figure 10 As shown, the start contact 6 includes a horizontal slider and a vertical slider. The inclined surfaces on the horizontal slider and the vertical slider abut against each other to form a wedge structure, converting the horizontal movement of the horizontal slider into the vertical movement of the vertical slider. When the pencil enters through the pen inlet hole, the pen body pushes the horizontal slider to move, and the bottom end of the vertical slider extends out and pushes the trigger rod 10. The bottom of the trigger rod 10 abuts against the trigger end of the micro switch 14 to trigger the micro switch 14 to turn on the circuit in the automatic pencil sharpener.

[0033] In this embodiment, the motor 17 drives the drive shaft 15 to rotate through a reduction gear set. The upper end of the drive shaft 15 is connected to the tool rest assembly, and the tool rest assembly rotates synchronously with the drive shaft 15 to perform the pencil sharpening operation. Among them, the multiple gears in the reduction gear set are meshed step by step, and the rotation directions of the last two gears are different, so they are divided into a forward rotation gear 4 and a reverse rotation gear 5. Since the rotation directions of the gears are only clockwise and counterclockwise, the forward and reverse directions are not clearly limited in this embodiment.

[0034] In this embodiment, the reduction gear set is fixedly installed on the tabletop of the support table 9, and the body of the motor 17 is fixedly installed at the position below the support table 9. The motor 17 shaft passes through and extends to the tabletop of the support table 9, and a gear meshing with the reduction gear set is provided on the motor 17 shaft. In order to prevent the pencil ash in the waste chip chamber from entering and contaminating the reduction gear set, the installation space of the reduction gear set needs to be separated from the waste chip chamber. The upper end of the drive shaft 15 extends into the bottom of the waste chip chamber for connecting the tool rest assembly.

[0035] In this embodiment, the pen entry trigger assembly is used to drive the shift gear 3 to move through a transmission structure by means of the entry of the pen body.

[0036] As Figures 1-11As shown, in this embodiment, an automatic short pen retraction device is disclosed, including a trigger mechanism, a shift gear 3, a forward gear 4, a reverse gear 5 and a transmission rod 2 that is transmission-connected to the pen advance and retraction assembly 8. After the short pen enters, the shift gear 3 is driven by the trigger mechanism to switch from being engaged with the forward gear 4 to being engaged with the reverse gear 5. The trigger mechanism includes a starting contact 6 and a pen advance trigger assembly. When the short pen descends to the lower part of the pen advance trigger assembly and the starting contact 6 is in the position of powering on, the shift gear 3 switches from being engaged with the forward gear 4 to being engaged with the reverse gear 5. The shift gear 3 and the transmission rod 2 can slide together to transmit torque.

[0037] In this embodiment, the starting contact 6 is located at the bottom of the pen feed trigger assembly, meaning that the trigger end of the pen feed trigger assembly is closer to the entrance of the pen feed hole than the trigger end of the starting contact 6. Therefore, when inserting a short pen, the end of the pen first disengages from the trigger end of the pen feed trigger assembly and then from the trigger end of the starting contact 6. The period between the end of the pen disengaging from the trigger end of the pen feed trigger assembly and before it disengages from the trigger end of the starting contact 6 constitutes the window period for the automatic pencil sharpener to automatically retract a short pen. During this window period, the circuitry within the automatic pencil sharpener remains connected, allowing the motor 17 to operate normally by driving the tool holder assembly via the reduction gear train and drive shaft 15.

[0038] Furthermore, in this embodiment, the pen advance / retract assembly 8 is located below the pen feed trigger assembly and includes two pen feed rollers. The two pen feed rollers are meshed with each other via gears, enabling synchronous and counter-rotating rotation of the two pen feed rollers. The transmission rod 2 utilizes a worm structure, with a helical tooth portion at its upper end, and one of the pen feed rollers is coaxially provided with a gear that meshes with the helical tooth portion. The rotation of the transmission rod 2 can drive the pen feed rollers to operate, thereby achieving a transmission connection between the pen advance / retract assembly 8 and the transmission rod 2.

[0039] Specifically, combined Figures 1-4 As shown, in this embodiment, the shift gear 3 and the transmission rod 2 can slide together to transmit torque, and the trigger mechanism also includes a fork rod 1. When the pen is advanced, the pen-advancing trigger assembly pushes the shift gear 3 to move through the fork rod 1.

[0040] Furthermore, the pen-feeding trigger assembly directly pushes the shift fork rod 1 when the pen is fed, and the shift fork rod 1 pushes the shift gear 3 to move relative to the transmission rod 2, and the shift gear 3 is elastically connected to the support platform 9.

[0041] Further, in this embodiment, the fork rod 1 and the transmission rod 2 are both vertically installed on the support table 9. A first elastic member 12 is sleeved on the fork rod 1. The upper end of the first elastic member 12 abuts against a protrusion on the rod body of the fork rod 1, and the lower end abuts against the support table 9. A second elastic member 13 is sleeved on the transmission rod 2. The upper end of the second elastic member 13 abuts against the shift gear 3, and the lower end abuts against the support table 9, thereby realizing the elastic connection between the shift gear 3 and the support table 9.

[0042] Further, in this embodiment, the transmission rod 2 is provided with an external spline structure, and the shift gear 3 is provided with a spline hole. The torque can be transmitted between the two through the sliding fit of the spline hole and the external spline.

[0043] Specifically, in another embodiment, the shift gear 3 is fixedly installed on the transmission rod 2. When penning, the penning trigger assembly pushes the transmission rod 2 to drive the shift gear 3 to move.

[0044] Further, in another embodiment, the shift gear 3 is fixedly installed on the transmission rod 2, that is, the shift gear 3 moves up and down synchronously with the whole transmission rod 2. Correspondingly, the transmission rod 2 is elastically connected to the support table 9, that is, the second elastic member 13 is sleeved on the transmission rod 2. The lower end of the second elastic member 13 abuts against the support table 9, and the upper end abuts against the shift gear 3 on the transmission rod 2. Correspondingly, the spiral tooth portion at the upper end of the transmission rod 2 is replaced with a spur gear structure, and a turbine meshing with the spur gear structure is coaxially arranged on one of the pen feed rubber rollers in the pen feed and retract assembly 8. When the whole transmission rod 2 moves vertically, the turbine remains meshed with the spur gear structure. When penning, the penning trigger assembly directly pushes the transmission rod 2 to move the whole transmission rod 2, so that the shift gear 3 moves from the position meshing with the reverse gear 5 to the position meshing with the forward gear 4.

[0045] Specifically, the penning trigger assembly includes a pair of swing rods 11 arranged in parallel. The trigger portion 11c on the swing rod 11 swings in the vertical direction following the rotation of the swing rod 11.

[0046] Further, in this embodiment, the two swing rods 11 form a pen clamping assembly. In order to reduce the number of parts, the pen clamping assembly and the penning trigger assembly are combined into one. The pen clamping assembly is suitable for clamping the pencil body to prevent the pencil from rotating idly synchronously with the tool rest during the pencil sharpening process. The two swing rods 11 are rotatably installed on the upper cover 7. A meshing portion 11b and a clamping portion 11a are provided on the rod body of the swing rod 11. The meshing portions 11b on the two swing rods 11 are meshed and connected to each other, and the two clamping portions 11a are arranged corresponding to the position of the penning hole. When the pencil is inserted into the penning hole, the pencil abuts against the clamping portion 11a to drive the swing rod 11 to swing downward. The two swing rods 11 rotate synchronously and in opposite directions. In this embodiment, at least one of the two swing rods 11 is elastically connected to the upper cover 7, so that the swing rod has a reset function.

[0047] Further, in combination with Figure 5 As shown, a trigger portion 11c is provided on the rod body of one of the swing rods 11. When the swing rod 11 rotates, the trigger portion 11c swings in the vertical direction and abuts against the upper end of the shift fork rod 1 during the swinging process, pushing the shift fork rod 1 downward.

[0048] Specifically, a clamping portion 11a is provided on the swing rod 11, and a clamping gap is formed between the clamping portions 11a.

[0049] Further, in combination with Figure 8 As shown, in this embodiment, three stepped surfaces are formed by the outward extension of the rod body of the shift fork rod 1. The three stepped surfaces have different axial heights along the shift fork rod 1, and complete cam surfaces are formed by the transition of curved surfaces between the stepped surfaces. One of the stepped surfaces is a delay surface 1b. Under the action of the elastic member, the upper end of the shift gear 3 abuts against the delay surface 1b. At this time, the shift gear 3 is disengaged from the forward rotation gear 4 and the reverse rotation gear 5, and the shift gear 3 is located at the delay pencil sharpening position. The other two of the three stepped surfaces are a pen feeding surface 1a and a pen retracting surface 1c respectively. Under the action of the elastic member, when the upper end of the shift gear 3 abuts against the pen feeding surface 1a, the shift gear 3 is meshed and connected with the forward rotation gear 4, that is, the shift gear 3 is located at the pen feeding position. When the shift gear 3 abuts against the pen retracting surface 1c, the shift gear 3 is meshed and connected with the reverse rotation gear 5, that is, the shift gear 3 is located at the pen retracting position.

[0050] Further, in combination with Figures 6-8 As shown, in this embodiment, a spline is provided at the lower part of the shift fork rod 1, and the first delay gear 18 is slidably engaged with the spline in a torque-transmitting manner. A second delay gear 19 is provided at the lower part of the forward rotation gear 4, and the second delay gear 19 is slidably engaged with the drive shaft 15 in a torque-transmitting manner. A connecting rod 16 is provided inside the drive shaft 15. When the tool rest assembly is connected to the drive shaft 15, the upper end of the connecting rod 16 extends into the tool rest assembly, and the lower end of the connecting rod 16 abuts against the second delay gear 19. During automatic pencil sharpening, the tip of the pencil continuously pushes the connecting rod 16 downward as it feeds the pen. The connecting rod 16 drives the second delay gear 19 to move downward, and the spring between the second delay gear 19 and the support table 9 is continuously compressed until the second delay gear 19 gradually meshes with the first delay gear 18. At the same time, the drive shaft 15 drives the first delay gear 18 to rotate through the second delay gear 19, and the first delay gear 18 drives the shift fork rod 1 to rotate. The shift gear 3 is switched from abutting against the pen feeding surface 1a to abutting against the delay surface 1b, thereby realizing the transition from the automatic pencil sharpening stage to the delay pencil sharpening stage. Similarly, the first delay gear 18 continues to drive the shift fork rod 1 to rotate, and the shift gear 3 is switched from abutting against the delay surface 1b to abutting against the pen retracting surface 1c, thereby realizing the transition from the delay pencil sharpening stage to the pen retracting stage.

[0051] In this embodiment, the working principle of the automatic short pencil retracting device is as follows:

[0052] First, after inserting the short pencil into the pencil insertion hole on the upper cover 7, the trigger end of the pencil first contacts the pen insertion trigger component. That is, the pen body drives the swing rod 11 to rotate through the clamping portion 11a. The trigger portion 11c on the swing rod 11 swings downward, and the trigger portion 11c presses the shift fork rod 1 downward. The shift gear 3 moves downward following the shift fork rod 1. The shift gear 3 moves from the position meshing with the reverse gear 5 to the position meshing with the forward gear 4. The short pencil continues to be inserted. The pen body of the short pencil triggers the start contact 6. The start contact 6 triggers the micro switch 14 through the trigger rod 10, and the circuit of the automatic pencil sharpener is turned on. The motor 17 starts to work. The motor 17 drives the tool holder to rotate through the reduction gear set and the transmission shaft. The forward gear 4 transmits the torque to the forward and backward pen assembly 8 through the power transmission of the shift gear 3 and the transmission rod 2, driving the forward and backward pen assembly 8 to perform a pen insertion action, and the automatic short pencil retracting device enters the automatic pencil sharpening stage. The short pencil continuously extends into the tool holder under the action of the forward and backward pen assembly 8.

[0053] After that, after the short pencil is inserted, its pen tail extends into the lower part of the pen insertion trigger component. The pen tail first disengages from the trigger end of the pen insertion trigger component, that is, the swing rod 11 automatically resets, and the clamping portion 11a and the trigger portion 11c swing upward. However, the pen body of the short pencil still abuts against the start contact 6, the micro switch 14 remains pressed by the trigger rod 10, and the motor 17 remains in the working state. The shift fork rod 1 is no longer restricted by the trigger portion 11c and moves upward under the action of the first elastic member 12. The shift gear 3 moves from the position meshing with the forward gear 4 to the position meshing with the reverse gear 5. The reverse gear 5 transmits the torque to the forward and backward pen assembly 8 through the power transmission of the shift gear 3 and the transmission rod 2, driving the forward and backward pen assembly 8 to perform a pen retraction action. The pencil continuously retracts until it extends out of the tool holder, the pen body disengages from the start contact 6, triggering the micro switch 14, and the circuit is disconnected.

[0054] Combined with Figure 11 As shown, in another embodiment, an automatic pencil sharpener is disclosed, including the automatic short pencil retracting device of this embodiment.

[0055] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0056] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0057] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the horizontal height of the first feature is less than that of the second feature.

[0058] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An automatic short pen retracting device, characterized in that: It includes a triggering mechanism, a shifting gear, a forward rotation gear, a reverse rotation gear, and a transmission rod that is drivingly connected to the advancing and retracting pen assembly. The shifting gear is driven by the triggering mechanism to switch from being engaged with the reverse rotation gear to being engaged with the forward rotation gear. The triggering mechanism includes a starting contact, a pen-advancing triggering assembly, and a fork rod. The pen-advancing triggering assembly is used to drive the shifting gear to move through a transmission structure by means of the entry of the pen body. When the short pen moves downward to the lower part of the pen-advancing triggering assembly and the starting contact is in the position of connecting to the power supply, the shifting gear switches from being engaged with the forward rotation gear to being engaged with the reverse rotation gear. The shifting gear is slidably mated with the transmission rod in a torque-transmissible manner, or the shifting gear is fixedly installed on the transmission rod; The starting contact is arranged at the pen-advancing hole position and is located at the lower part of the pen-advancing triggering assembly. The starting contact includes a horizontal slider and a vertical slider. The inclined surfaces on the horizontal slider and the vertical slider abut against each other to form a wedge structure, converting the horizontal movement of the horizontal slider into the vertical movement of the vertical slider; The pen-advancing triggering assembly includes a pair of parallel swing rods. The two swing rods form a pen-clamping assembly. The two swing rods are rotatably installed on the upper cover. A meshing portion and a clamping portion are provided on the rod body of the swing rod. The meshing portions on the two swing rods are meshingly connected to each other. The two clamping portions are arranged corresponding to the position of the pen-advancing hole. The triggering portion on the swing rod swings in the vertical direction following the self-rotation of the swing rod; The fork rod and the transmission rod are both vertically installed on the support platform. A first elastic member is sleeved on the fork rod, and a second elastic member is sleeved on the transmission rod; Three stepped surfaces extend outward from the rod body of the fork rod. The three stepped surfaces have different axial heights along the fork rod, and complete cam surfaces are formed by the transition of curved surfaces between the stepped surfaces; Among them, the starting contact is located at the lower part of the pen-advancing triggering assembly. After the short pen advances, its pen tail extends into the lower part of the pen-advancing triggering assembly. The pen tail first disengages from the triggering end of the pen-advancing triggering assembly, and the swing rod automatically resets. The fork rod moves upward without the restriction of the swing rod. The shifting gear moves from the position engaged with the forward rotation gear to the position engaged with the reverse rotation gear. The reverse rotation gear transmits torque to the advancing and retracting pen assembly through the power transmission of the shifting gear and the transmission rod, driving the advancing and retracting pen assembly to perform a pen-retracting action. The pencil continuously retracts the pen until it extends out of the knife rest, and the pen body disengages from the starting contact, triggering the microswitch and disconnecting the circuit.

2. The automatic short pen retracting device according to claim 1, wherein: During pen advancement, the pen-advancing triggering assembly pushes the shifting gear to move through the fork rod.

3. The automatic short pen retracting device according to claim 1, wherein: During pen advancement, the pen-advancing triggering assembly pushes the transmission rod to drive the shifting gear to move.

4. An automatic short pen retracting device according to claim 1, characterized in that: The triggering portion on the swing rod swings in the vertical direction following the self-rotation of the swing rod.

5. An automatic short pen retracting device according to claim 4, characterized in that: The swing rod is provided with clamping portions, and a clamping gap is formed between the clamping portions.

6. An automatic pencil sharpener, characterized in that: It includes the automatic short pen retracting device according to any one of claims 1-5.

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