Automatic pencil with a core that is thrown out

Abstract

The utility model discloses a kind of automatic pencils of fling core, including pen holder and lead core, sleeve, chuck assembly, storage core pipe, counterweight spring are respectively arranged in pen holder, chuck assembly includes chuck, connecting seat, chuck front end includes claw, sleeve is movably sleeved on connecting seat, reset spring is arranged between sleeve and connecting seat, the front end of sleeve is provided with lock hoop, lock hoop is sleeved in the front end of chuck, counterweight spring is movably sleeved on storage core pipe and with the rear end of connecting seat form push cooperation, claw is three, three claws are evenly distributed along the center line of chuck, claw front end inside has recess, the lead core is columnar, lead core includes three side walls and three convex rib parts along circumference, the recess of claw can be formed with lead core convex rib part and is engaged. The automatic pencil of fling core of the utility model can solve the problem that lead core is prone to retreat when writing due to the insufficient of the existing automatic pencil to thick lead core clamping force.

Description

Technical Field

[0001] This utility model relates to a self-contained automatic pencil that produces lead by flicking. Background Technology

[0002] Currently, there is a type of mechanical pencil on the market that allows the lead to be ejected by swinging the pen. Its structure and working principle are as follows: a counterweight spring is movably installed inside the pen barrel. When the pen is swung back and forth, the counterweight spring inside the pen will move back and forth. When the counterweight spring moves forward, it will push the chuck assembly forward by hitting it. The chuck of the chuck assembly will extend forward from the locking clamp. As the chuck extends forward, it clamps the lead and moves forward, realizing the lead ejection action. When the pen is stopped or when the counterweight spring moves backward, the return spring drives the chuck assembly to return to its original position. The chuck retracts back into the locking clamp and forms a clamping and positioning of the lead, so that the lead will not move backward on its own when writing. A mechanical pencil that uses a swinging motion to eject the lead is disclosed in Chinese Utility Model No. CN206374414U.

[0003] For mechanical pencils of this type, to facilitate user operation and make lead ejection easier, a weaker return spring is typically used. However, when the pencil is written upright, the weight of the counterweight spring, clip assembly, and lead reservoir acts on the return spring, weakening the backward force on the clip assembly. This results in a weaker clamping force on the lead, making it prone to lead slippage due to excessive writing pressure. Conversely, using a stronger return spring might make it difficult for the clip assembly to be pushed forward by the counterweight spring when the pencil is shaken, making lead ejection even more strenuous. This is especially true for mechanical pencils with thicker leads (1.3~2.0mm), where the larger surface area makes it difficult for traditional clip structures to apply force evenly, resulting in more dispersed pressure and thus requiring a higher clamping force. In addition, mechanical pencils with thick leads need to have the tip of the lead sharpened with a lead sharpener before writing. Regular leads are cylindrical and rely solely on friction and the clamp to prevent rotation. During sharpening, the lead can easily rotate along with the lead sharpener, affecting the sharpening operation.

[0004] To address this issue, the current mainstream solution involves adding texture to the inside of the clip, the area where the clip contacts the lead, to increase friction and improve the lead-retardant effect. However, due to limitations in current injection molding processes, it's difficult to integrally mold textures onto the inside of a conventional plastic clip. Therefore, clips for these swing-type mechanical pencils are generally made of copper, with textures formed on the copper clip through milling or turning. This results in higher production costs for the clip component. Another solution is to use a heavier counterweight spring to balance the return spring's force and ensure effective lead ejection. However, the limited internal space of the pencil necessitates increasing the pencil's size to accommodate a sufficiently large counterweight spring while ensuring it has enough room to move. An excessively heavy counterweight spring also increases the pencil's weight, affecting the writing feel. Summary of the Invention

[0005] The present invention aims to provide a mechanical pencil with a flick-to-extract lead, which solves the problem that the lead in existing mechanical pencils is prone to slipping back during writing due to insufficient clamping force on the thick lead.

[0006] To achieve the above objectives, this utility model provides a swing-action mechanical pencil, comprising a barrel and a lead core. The barrel includes a sleeve, a clamp assembly, a lead storage tube, and a counterweight spring. The clamp assembly includes a clamp and a connecting seat connecting the rear end of the clamp and the front end of the lead storage tube. The front end of the clamp includes a gripper. The sleeve is movably fitted onto the connecting seat, and a return spring is abutting between the sleeve and the connecting seat. The front end of the sleeve is provided with a locking clamp that cooperates with the gripper to clamp and position the lead core. The locking clamp is fitted onto the front end of the clamp. The counterweight spring is movably fitted onto the lead storage tube and forms a pushing engagement with the rear end of the connecting seat.

[0007] While the pen is swung back and forth, the counterweight spring inside the pen moves back and forth. Since the sleeve remains stationary due to the restriction of the pen barrel, when the counterweight spring moves forward, it pushes the chuck assembly (along with the lead reservoir tube) against the return spring by hitting the connecting seat of the chuck assembly. The chuck's jaws extend forward from the locking clamp and clamp the lead forward, realizing the lead ejection action. As the jaws disengage from the locking clamp when they extend forward, they detach from the lead. When the pen stops being swung or when the counterweight spring moves backward, the return spring drives the chuck assembly to return to its original position. The chuck retracts into the locking clamp and tightens with it, re-clamping and positioning the lead, preventing the lead from moving backward on its own when writing.

[0008] In this utility model, there are three grippers, which are evenly distributed circumferentially along the center line of the chuck. The inner side of the front end of the gripper has a groove. The lead core is columnar and includes three sidewalls and three protruding ridges formed between adjacent sidewalls. The cross-section of the lead core is an equilateral triangle or an approximately equilateral triangle, such as a rounded triangle or an arc triangle. The outline of the protruding ridges can be a sharp angle, a rounded angle, or an obtuse angle. The groove of the gripper allows the protruding ridges of the lead core to be inserted, and the sidewall of the groove can apply pressure to it when pressure is applied to form an engagement.

[0009] In this invention, the three jaws can apply pressure and clamp the lead core evenly in three directions. While clamping, the jaw grooves have an interlocking effect on the protruding part of the lead core, which can further improve the clamping and positioning effect of the lead core and prevent it from moving backward when writing under pressure. In addition, this cooperation structure can also limit the rotation of the lead core relative to the clamp.

[0010] Furthermore, the inner side of the front end of the gripper has an inwardly protruding inner boss, and the groove is disposed on the inner boss. The inner side of the rear end of the gripper has an arc-shaped concave portion, which is located behind the groove. The groove is positioned closer to the center line of the gripper than the arc-shaped concave portion. The arc-shaped concave portion and the groove are connected by a guide groove. The guide groove includes two guide sidewalls with a forwardly narrowing spacing and a guide bottom inner wall connected between the two guide sidewalls. When the lead core is inserted forward between the three grippers, the guide groove can guide the convex portion of the lead core in the circumferential direction (through the guiding effect of the two guide sidewalls) and the radial direction (through the guiding effect of the guide bottom inner wall), guiding it into the groove. This ensures that all three convex portions can be accurately inserted into the grooves of the three grippers, improving reliability during use.

[0011] Furthermore, the outer side of the front end of the gripper has an outwardly protruding boss. The outer side of the outer boss has a rear conical guide surface, a middle conical guide surface, and a front conical guide surface connected in sequence. The taper of the rear conical guide surface and the front conical guide surface is greater than that of the middle conical guide surface. When the gripper moves backward, the force cooperation between the conical guide surfaces on the outer side of the outer boss and the locking clamp can push the front end of the gripper toward the center, thereby improving the gripping effect on the lead core. In addition, the outer boss can also form a limiting function to prevent the locking clamp and the sleeve from coming off the gripper forward.

[0012] Furthermore, the groove has a bottom inner wall and two side walls connected to both sides of the bottom inner wall. The side walls of the groove include a first side wall portion that is inward and connected to the bottom inner wall, and a second side wall portion that is outward and connected to the groove opening. The distance between the second side wall portions of the two side walls of the groove increases towards the groove opening. When the gripper clamps and applies pressure to the lead core, the side walls of the groove can press against the two side wall areas adjacent to the protruding part of the lead core, achieving a biting effect and further improving the axial positioning effect of the lead core. In addition, it can also guide the protruding part to be inserted into the groove along the opening when the gripper releases from the lead core and clamps it again, improving the cooperation effect between the gripper and the lead core.

[0013] Furthermore, the convex ridge of the lead core has a convex arc-shaped surface, which can improve the contact fit between the convex ridge and the inner wall of the gripper groove, reduce wear on the convex ridge of the lead core, and also improve the strength of the convex ridge.

[0014] Furthermore, the rear end of the chuck includes a cylindrical insertion part, which is inserted and positioned with the connecting seat. The jaws are integrally connected to the front end of the insertion part, and the insertion part has an inner hole adapted to the shape of the lead core, which can prevent the lead core from rotating.

[0015] Furthermore, a detachable button is movably provided at the rear end of the pen barrel. The button is connected to the lead storage tube. In addition to flicking the lead out, the lead storage tube, the chuck assembly, and other components can also be pushed forward by pressing the button to realize the lead out function of the pen. A lead sharpener is provided on the button. When it is necessary to sharpen the lead, the button can be removed from the rear end of the pen and the end of the lead can be sharpened by the lead sharpener.

[0016] Furthermore, the rear end of the chuck and the connecting seat form an anti-rotation fit, the connecting seat and the sleeve form an anti-rotation fit, and the sleeve and the pen barrel form an anti-rotation fit. The chuck indirectly forms an anti-rotation fit with the pen barrel through the connecting seat and the sleeve. When gripping the pen barrel and sharpening the lead core with the lead core using the lead core sharpener, the lead core can be prevented from rotating, thus improving the sharpening effect of the lead core.

[0017] Furthermore, the chuck is made of plastic, which has a certain degree of elasticity, reducing the requirements for component fitting precision and improving the gripping effect of the jaws on the protruding parts. Thanks to the fitting structure between the lead core and the chuck in this invention, the chuck, which is formed by injection molding, can also form a reliable clamping and positioning effect on the lead core. Compared with the copper chuck solution in the prior art, the raw material and manufacturing costs are lower, solving the problem of the weak clamping effect of traditional plastic chucks on lead cores, and reducing the requirements for the return spring force, the weight of the counterweight spring, and the internal space of the pen. Attached Figure Description

[0018] Figure 1This is a structural diagram of an embodiment of the present utility model;

[0019] Figure 2 This is a partial cross-sectional view of an embodiment of the present utility model. Figure 1 ;

[0020] Figure 3 This is a partial cross-sectional view of an embodiment of the present utility model. Figure 2 ;

[0021] Figure 4 This is a disassembly diagram of the locking clamp, sleeve, clamp assembly, and return spring according to an embodiment of the present utility model;

[0022] Figure 5 This is an axial schematic diagram of the locking clamp, sleeve, chuck assembly, and return spring in the assembled state according to an embodiment of the present utility model.

[0023] Figure 6 For along Figure 5 Sectional view of section line AA in the middle;

[0024] Figure 7 This is a structural diagram of the gripper in an embodiment of the present invention.

[0025] Figure 8 This is a partial sectional perspective view of the chuck in an embodiment of the present invention;

[0026] Figure 9 This is a structural diagram of the rear end of the chuck in an embodiment of the present invention. Detailed Implementation

[0027] Examples of embodiments of this utility model of a self-contained mechanical pencil with a lead-out mechanism include: Figure 1-9 As shown: The pen includes a barrel 1 and a lead core 2. The barrel 1 contains a sleeve 3, a clamp assembly, a lead storage tube 4, and a counterweight spring 5. The clamp assembly includes a clamp 61 and a connecting seat 62 connecting the rear end of the clamp 61 and the front end of the lead storage tube 4. The front end of the clamp 61 includes a gripper 611. The sleeve 3 is movably fitted onto the connecting seat 62. The fitting joint between the sleeve 3 and the connecting seat 62 has a non-circular profile. Alternatively, matching ribs and grooves can be provided between the two components for limiting relative rotation between the insertion part 612 and the connecting seat 62. The sleeve 3 is inserted into the inner side of the pen barrel 1. The insertion and mating part between the sleeve 3 and the inner wall of the pen barrel 1 adopts a non-circular contour. Alternatively, a matching rib and a groove can be set between the two parts to limit the relative rotation between the sleeve 3 and the pen barrel 1. A return spring 7 is provided between the sleeve 3 and the connecting seat 62. The front end of the sleeve 3 is provided with a locking clamp 8 that cooperates with the gripper 611 to clamp and position the lead core 2. The locking clamp 8 is made of metal and is sleeved on the front end of the chuck 61. The counterweight spring 5 is movably sleeved on the core storage tube 4 and forms a pushing cooperation with the rear end of the connecting seat 62.

[0028] While the pen is swung back and forth, the counterweight spring 5 inside the pen will move back and forth. Since the sleeve 3 is kept stationary by the pen barrel 1, when the counterweight spring 5 moves forward, it pushes the chuck assembly (along with the core storage tube 4) against the forward movement of the return spring 7 by hitting the connecting seat 62 of the chuck assembly. As the return spring 7 is compressed, the jaws 611 of the chuck 61 will extend forward from the locking clamp 8 and clamp the lead core 2 forward, realizing the core release action of the lead core 2. And since the jaws 611 are disengaged from the locking clamp 8 when they extend forward, the jaws 611 will return to their original position and open under their own elasticity (as shown in the image). Figure 7 (As shown in the state) the gripper 611 will detach from the lead 2, and the damping force between the lead outlet hole 11 at the front end of the pen barrel 1 and the lead 2 will keep the lead 2 in the position after moving forward; when the pen stops swinging or when the counterweight spring 5 moves backward, the return spring 7 will drive the chuck assembly to move backward, and the chuck 61 will retract into the locking clamp 8 and tighten with the locking clamp 8, re-establishing the clamping and positioning of the lead 2, so that the lead 2 will not move backward on its own when writing.

[0029] like Figure 5 , Figure 7 , Figure 8 , Figure 9 As shown, there are three grippers 611, which are evenly distributed circumferentially along the center line of the chuck 61. Each gripper 611 has a groove 613 on its inner front end. The lead core 2 is cylindrical and includes three sidewalls 21 and three protruding ridges 22 formed between adjacent sidewalls 21. The cross-section of the lead core 2 is approximately equilateral triangular. The three sidewalls 21 of the lead core 2 have a flat structure, and the protruding ridges 22 have rounded corners and a convex arc-shaped profile, smoothly transitioning and connecting with adjacent sidewalls 21. In other aspects... In this embodiment, the cross-section of the lead core 2 can be an equilateral triangle or other approximately equilateral triangle shapes, such as an arc triangle. The outline of the protruding ridge 22 can also be a sharp angle or an obtuse angle. The groove 613 of the gripper 611 allows the protruding ridge 22 of the lead core 2 to be inserted, and when pressure is applied, the two side walls of the groove 613 can apply pressure to it to form an engagement. The chuck 61 is made of plastic, which has a certain degree of elasticity, thereby reducing the requirements for the precision of the component fit and improving the engagement effect of the gripper 611 on the protruding ridge 22.

[0030] In this invention, the three grippers 611 can apply pressure and clamp the lead core 2 evenly in three directions. While clamping, the grooves 613 of the grippers 611 have an interlocking effect on the protruding ridges 22 of the lead core 2, which can further improve the clamping and positioning effect of the lead core 2 and prevent it from moving backward when writing under pressure. In addition, this cooperation structure can also prevent the lead core 2 from rotating relative to the clamp 61.

[0031] Compared to the copper chuck in the prior art, the chuck 61 in this embodiment is made of plastic, which has lower raw material and manufacturing costs. It solves the problem that the traditional plastic chuck has a weak clamping effect on the lead core 2, and can reduce the requirements for the spring force of the return spring 7, the weight of the counterweight spring 5, and the internal space of the pen.

[0032] The inner side of the front end of the gripper 611 has an inwardly protruding inner boss 614, and the groove 613 is disposed on the inner boss 614. The inner side of the rear end of the gripper 611 has an arc-shaped inner concave portion 615, which is located behind the groove 613. The groove 613 is positioned closer to the centerline of the gripper 61 than the arc-shaped inner concave portion 615, i.e., there is a distance difference between them in the radial direction. The arc-shaped inner concave portion 615 and the groove 613 are connected by a guide groove 616, which includes two guide sides that narrow forward. The guide groove 6161 and the guide bottom inner wall 6162 connected between the two guide side walls 6161 can guide the protruding part 22 of the lead core 2 in the circumferential direction (through the guiding effect of the two guide side walls 6162) and the radial direction (through the guiding effect of the guide bottom inner wall 6162) when the lead core 2 is inserted forward between the three jaws 611. This guides the lead core 2 forward into the groove 613, so that the three protruding parts 22 can be accurately inserted into the grooves 613 of the three jaws 611, thus improving the reliability during use.

[0033] The gripper 611 has an outwardly protruding outer boss 617 on its outer side. The outer side of the outer boss 617 has a rear conical guide surface 6171, a middle conical guide surface 6172, and a front conical guide surface 6173 connected in sequence. The taper of the rear conical guide surface 6171 and the front conical guide surface 6172 is greater than that of the middle conical guide surface 6172. When the gripper 611 moves backward, the force cooperation between the conical guide surfaces on the outer side of the outer boss 617 and the locking clamp 8 can push the front end of the gripper 611 toward the center, thereby improving the gripping effect on the lead core 2. In addition, the outer boss 617 can also form a limiting function to prevent the locking clamp 8 and the sleeve 3 from coming off the gripper 611 forward.

[0034] The groove 613 has a bottom inner wall 6131 and two side walls connected to both sides of the bottom inner wall 6131. ​​The side walls of the groove 613 include a first side wall portion 6132a that is inward and connected to the bottom inner wall 6131, and a second side wall portion 6132b that is outward and connected to the groove opening. The distance between the second side wall portions 6132b of the two side walls of the groove 613 increases towards the groove opening, that is, gradually increases in the radial and inward direction. When the gripper 611 clamps and applies pressure to the lead core 2, the side walls of the groove 613 can press against the areas of the two side walls 21 adjacent to the protruding ridge portion 22 of the lead core 2, achieving a biting effect and further improving the axial positioning effect of the lead core 2. In addition, it can also guide the protruding ridge portion 22 along the groove opening and insert it into the groove when the gripper 611 is released from the lead core 2 and clamped again, improving the cooperation effect between the gripper 611 and the lead core 2.

[0035] The convex ridge 22 with a convex arc surface can improve the contact fit between the convex ridge 22 and the inner wall 6131 of the groove 613 of the gripper 611, reduce the wear on the convex ridge 22 of the lead core 2, and also improve the strength of the convex ridge 22.

[0036] The rear end of the chuck 61 includes a cylindrical insertion part 612. The insertion part 612 at the rear end of the chuck 61 and the connecting seat 62 are inserted and positioned together. The insertion part adopts a non-circular contour. Alternatively, matching ribs and grooves can be provided between the two parts to limit the relative rotation between the insertion part 612 and the connecting seat 62. The jaws 611 are integrally connected to the front end of the insertion part 612. The insertion part 612 has an inner hole 6121 that matches the shape of the lead core 2, which can prevent the lead core 2 from rotating. The front end of the inner hole 6121 is located in the middle position of the rear ends of the three jaws 611.

[0037] A button 9 is movably provided at the rear end of the pen barrel 1. The button 9 is connected to the lead storage tube 4. In addition to flicking the lead out, the lead storage tube 4, the chuck assembly and other components can also be pushed forward by pressing the button 9 to realize the lead out function of the pen. A lead sharpener 91 is provided on the button 9, and the end of the lead 2 can be sharpened by the lead sharpener.

[0038] Based on the anti-rotation fit between the chuck 61 and the connecting seat 62, between the connecting seat 62 and the sleeve 3, and between the sleeve 3 and the pen barrel 1, the lead core is prevented from rotating when the pen barrel 1 is gripped and the lead core tip is sharpened by the lead core sharpener, thus improving the sharpening effect of the lead core.

[0039] The above embodiments are merely one preferred embodiment of the present utility model. Ordinary changes and substitutions made by those skilled in the art within the scope of the present utility model's technical solution are all included within the protection scope of the present utility model.

Claims

1. A swing-action mechanical pencil, comprising a barrel and a lead core, wherein the barrel contains a sleeve, a clip assembly, a lead storage tube, and a counterweight spring, wherein... The chuck assembly includes a chuck, a connecting seat connecting the rear end of the chuck and the front end of the lead storage tube, the front end of the chuck including jaws, a sleeve movably sleeved on the connecting seat, a return spring abutting between the sleeve and the connecting seat, the front end of the sleeve being provided with a locking clamp that cooperates with the jaws to clamp and position the lead core, the locking clamp being sleeved on the front end of the chuck, the counterweight spring being movably sleeved on the lead storage tube and forming a pushing cooperation with the rear end of the connecting seat, characterized in that: there are three jaws, the three jaws are evenly distributed circumferentially along the center line of the chuck, the front end of the jaws has a groove, the lead core is columnar, the lead core includes three sidewalls and three protruding ridges formed between adjacent sidewalls circumferentially, the grooves of the jaws allow the protruding ridges of the lead core to be inserted and can form a bite when pressure is applied.

2. The automatic pencil with lead ejection according to claim 1, characterized in that: The inner side of the front end of the gripper has an inwardly protruding inner boss, and the groove is disposed on the inner boss. The inner side of the rear end of the gripper has an arc-shaped concave portion, which is located behind the groove. The groove is positioned closer to the center line of the gripper than the arc-shaped concave portion. The arc-shaped concave portion and the groove are connected by a guide groove. The guide groove includes two guide sidewalls with a forwardly narrowing spacing and a guide bottom inner wall connected between the two guide sidewalls.

3. The automatic pencil with lead ejection according to claim 1, characterized in that: The front end of the gripper has an outwardly protruding outer boss, and the outer side of the outer boss has a rear conical guide surface, a middle conical guide surface, and a front conical guide surface connected in sequence. The taper of the rear conical guide surface and the front conical guide surface is greater than that of the middle conical guide surface.

4. The automatic pencil with lead ejection according to claim 1, characterized in that: The groove has a bottom inner wall and two side walls connected to both sides of the bottom inner wall. The side walls of the groove include a first side wall portion that is inward and connected to the bottom inner wall, and a second side wall portion that is outward and connected to the groove opening. The distance between the second side wall portions of the two side walls of the groove increases towards the groove opening.

5. The automatic pencil with lead ejection according to claim 4, characterized in that: The convex ridge of the lead core has a convex arc-shaped surface.

6. The mechanical pencil with lead ejection according to claim 1, characterized in that: The rear end of the chuck includes a cylindrical insertion part, which is inserted and positioned with the connecting seat. The jaws are integrally connected to the front end of the insertion part, and the insertion part has an inner hole adapted to the shape of the lead core.

7. The mechanical pencil with lead ejection according to claim 1, characterized in that: The pen barrel has a detachable button at its rear end, which is connected to the lead storage tube. The button is equipped with a lead sharpener.

8. The automatic pencil with lead ejection according to claim 1, characterized in that: The rear end of the chuck and the connecting seat form an anti-rotation fit, the connecting seat and the sleeve form an anti-rotation fit, and the sleeve and the pen barrel form an anti-rotation fit.

9. The mechanical pencil with lead ejection mechanism according to any one of claims 1 to 8, characterized in that: The clamp is made of plastic.

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