Pen with refill capable of stretching out and drawing back automatically

Abstract

The pen comprises a pen holder, the refill and a refill self-locking mechanism, the refill self-locking mechanism is supported at the rear end of the refill, a first spring is arranged between the front end of the refill and the pen holder, the refill self-locking mechanism comprises a sleeve, a connecting rod, a balancing weight, a sliding block and a second spring, a window is formed in the side portion of the sleeve, and the sliding block is arranged in the window. The sliding block is transversely and movably arranged at a window of the sleeve, the front end of the connecting rod is movably arranged on the inner side of the sleeve in a penetrating mode and is in transmission connection fit with the sliding block, the rear end of the connecting rod is connected with the balancing weight, the second spring acts between the sleeve and the connecting rod, and the connecting rod and the sleeve are in guiding movement fit through a protruding shaft and an inclined guide groove between the connecting rod and the sleeve. And a counterweight for balancing the gravity center is arranged at the front part of the pen holder. The pen with the refill capable of automatically stretching out and drawing back has the advantages of being few in parts and simple in structure.

Description

Technical Field

[0001] The invention relates to a pen with an automatically retractable pen core. Background Art

[0002] Currently, there is a type of pen on the market that can automatically extend and retract the pen core according to gravity. When the pen is placed vertically, the pen core automatically extends under the action of gravity and remains in the core-out state, making it convenient for writing. When the pen is placed horizontally or inverted, the pen core automatically retracts into the pen barrel to achieve automatic core retraction. This type of pen can reduce user operations and is more convenient to use.

[0003] There are currently two types of pens that eject the lead by gravity. One type adopts a solution as shown in the Chinese invention patent - a connecting rod structure of an automatic reset pen (CN221698336U), which includes a pen core, a housing, a counterweight, a reset structure, a transmission component and a locking member. The transmission component is composed of a first connecting member, a connecting rod, a rotating member and a second connecting member connected in sequence, and the extension or retraction of the pen core is achieved by the coordinated cooperation between the counterweight, the reset structure and the transmission component; the other type adopts a solution as shown in the Chinese invention patent - a ball locking structure of a writing tool with a telescopic member (CN106274162B), which includes an advance and retreat member, a rolling body, etc. The rolling body is in contact with the side of the advance and retreat member, and the telescopic locking of the telescopic member is achieved with the help of components such as a snap-on member.

[0004] The above two types of writing instruments are more complex and have higher requirements on manufacturing and assembly processes. Summary of the invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides a pen with fewer parts and a simpler structure and an automatically retractable pen core.

[0006] The pen with automatically retractable refill of the present invention comprises a pen holder, a refill arranged in the pen holder, and a refill self-locking mechanism. The refill self-locking mechanism is supported at the rear end of the refill and can move along the front-back direction of the pen. A first spring is arranged between the front end of the refill and the pen holder. The refill self-locking mechanism comprises a sleeve, a connecting rod, a counterweight, a slider, and a second spring. A window is arranged at the side of the sleeve. The slider is arranged at the window of the sleeve for transverse movement. The front end of the connecting rod is movably arranged in the front-back direction and penetrates the inner side of the sleeve and is transmission-connected and matched with the slider. The rear end of the connecting rod is connected to the counterweight. The block is preferably made of metal, the second spring acts between the sleeve and the connecting rod and is used to drive the connecting rod to move backward relative to the sleeve, and the connecting rod and the sleeve form a guiding movement fit through the convex shaft and the inclined guide groove therebetween, so that when the connecting rod moves forward and backward relative to the sleeve, it can drive the slider to move laterally outward and inward along the window of the sleeve respectively, and the slider forms an abutment fit with the inner wall of the pen barrel when extended, and a limiting portion is provided on the inner side of the pen barrel for limiting the position with the front end of the sleeve; a counterweight for balancing the center of gravity is provided at the front of the pen barrel, and the counterweight is preferably made of metal.

[0007] When the writing tool is needed, the pen is placed vertically, and the refill self-locking mechanism and the refill move forward under the action of gravity against the elastic force of the first spring, so that the refill extends out from the front end of the pen barrel. During the forward movement of the refill self-locking mechanism, when the front end of the sleeve moves to a position limited by the limiting portion, the counterweight block and the connecting rod move forward relative to the sleeve against the elastic force of the second spring under the action of gravity, and at the same time drive the slider to extend outward laterally along the window of the sleeve, and the slider and the inner wall of the pen barrel form abutment and fit. During the writing process, due to the damping when the slider and the inner wall of the pen barrel abut and fit, the refill can be locked in the refill position, and the refill can be prevented from retreating due to writing pressure; when the writing tool is not in use, the pen is placed horizontally, and the gravity direction of the refill and the refill self-locking mechanism is no longer in the same direction as the elastic force direction of the first and second springs. The counterweight block and the connecting rod move backward relative to the sleeve under the action of the second spring, so that the slider retracts laterally inward, and the refill and the refill self-locking mechanism as a whole move backward under the action of the first spring, realizing the automatic refill retraction function.

[0008] Compared with the prior art, the above-mentioned solution for realizing automatic extension and retraction of the pen core has fewer parts, a simpler structure, and relatively simple assembly and processing of the parts. It is also highly reliable and is not prone to jamming.

[0009] Furthermore, the slider includes a sleeve portion and an abutment portion, the abutment portion is arranged at one side of the sleeve portion, the sleeve portion and the connecting rod form a movable sleeve fit, the guide groove is arranged at the side of the sleeve portion, and the convex shaft is arranged on the connecting rod. When the connecting rod moves forward and backward relative to the slider, the slider moves horizontally through the convex shaft and the guide groove.

[0010] Furthermore, guide grooves are symmetrically arranged on both sides of the sleeve portion, and the guide grooves penetrate the inner and outer sides of the sleeve portion. A connecting hole is arranged on the connecting rod, and the convex shaft is composed of two ends of a metal rod fixedly inserted in the connecting hole. During assembly, the connecting rod is first inserted into the sleeve portion, and then the metal rod is inserted into the connecting hole of the connecting rod along the guide groove for installation and positioning. The structure is simple and the assembly is convenient.

[0011] Furthermore, an annular retaining wall is provided on the inner side of the sleeve near the rear end, and an active cavity is formed between the rear end of the sleeve and the annular retaining wall. A connecting block is provided at the rear end of the connecting rod, and the connecting block is movably arranged in the active cavity. The connecting rod is connected and cooperated with the front end of the counterweight block through the connecting block. The second spring is sleeved on the connecting rod and respectively abuts and cooperates with the annular retaining wall and the connecting block. The overall structure is simple and compact, ensuring the stability of the force application direction of the second spring.

[0012] Furthermore, a plug-in hole is provided at the rear end of the connecting block, and a plug-in block is provided at the front end of the counterweight block, which is plugged in and positioned with the plug-in hole, so as to achieve fixed fit between the counterweight block and the connecting rod and prevent the counterweight block from shaking; a positioning hole is provided at the front end of the sleeve, which is plugged in and positioned with the rear end of the pen core, so as to achieve relative fixation between the sleeve and the pen core and improve the fit effect.

[0013] Furthermore, the pen shaft includes a front section, a rear section and a connecting section, the front end of the connecting section is screwed to the rear end of the inner hole of the front section, the rear end of the connecting section is inserted and positioned at the front end of the inner hole of the rear section, the limiting portion is composed of the rear end of the connecting section, and the circumferential limiting cooperation between the rear end side portion of the connecting section and the side wall of the inner hole of the rear section is equipped with a slide groove and a convex strip arranged along the front and rear directions of the pen. During installation, the rear end of the connecting section can be inserted into the rear section of the pen shaft first, and the screw connection between the front end of the connecting section and the front section can be realized when the rear section is rotated relative to the front section, which is relatively convenient to operate. The axial limiting cooperation between the rear end side portion of the connecting section and the side wall of the inner hole of the rear section is equipped with two annular convex ribs arranged along the circumference of the pen, which can prevent the rear end of the connecting section from escaping from the inner hole of the rear section.

[0014] Furthermore, the counterweight is a cylindrical counterweight (including an annular one), which is arranged inside the pen holder and sleeved outside the pen core, and can be a spirally wound metal wire, and the cylindrical counterweight is used to adjust the center of gravity of the pen and improve the writing feel. The counterweight with this structure is simple in structure and easy to assemble.

[0015] Furthermore, a pen clip is provided at the rear end side of the pen barrel, and the pen clip can move forward and backward relative to the pen barrel. A clamping piece is movably provided between the pen clip and the pen barrel, and an opening is provided at the side of the pen barrel. When the pen clip moves relative to the pen barrel, the clamping end of the clamping piece can be driven to extend into the inside of the pen barrel or retract along the opening. The side front and side rear of the counterweight block both include a positioning part that can form a clamping and positioning match with the clamping end of the clamping piece when it extends into the inside of the pen barrel. The front edge of the counterweight block can serve as the positioning part of its side front, and the annular groove provided in the middle of the counterweight block can serve as the positioning part of its side rear. When the clamping end of the clamping piece and the positioning part of the counterweight block are clamped and matched, the counterweight part can be kept in the current position, so that the pen core can be kept in the core-out or core-retracting position, so that it is not affected by the posture of the pen, for example, it can still keep the core out when it is placed horizontally, and it can still keep the core retracted when it is placed vertically, especially when the pen is carried around, it can prevent the pen core from automatically extending.

[0016] Furthermore, the clamping part is a metal spring arranged between the pen clip and the pen barrel, one end of the metal spring is a clamping end, the other end is a fixed end, a curved portion is formed between the clamping end and the fixed end, the fixed end is fixed to the inner side of the pen clip, a recess is formed between the pen clip and the pen barrel for the curved portion of the metal spring to be placed, the recess is arranged at a position close to the opening on the side of the pen barrel, the recess includes a side wall adjacent to the opening, and the clamping end forms an elastic compression fit with the side wall. When the pen clip moves forward and backward relative to the pen barrel, it can also drive the metal spring to move forward and backward relative to the pen barrel. Since the clamping end of the metal spring is pressed and contacted with the side wall of the recess, it can move along the side wall with the movement of the pen clip, and when it moves to the opening, it extends into the inner side of the pen barrel under its own elastic action, and can cooperate with the counterweight.

[0017] Furthermore, the side wall of the notch is provided with a positioning rib, and the clamping end is provided with a positioning groove that cooperates with the positioning rib. Through the cooperation of the positioning rib and the positioning groove, the metal spring and the pen holder can be positioned, and the pen clip and the pen holder can be kept in position to prevent them from shaking. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the assembly of an embodiment of the present invention; Figure 2 It is a schematic diagram of the assembly of the self-locking mechanism of the pen core according to an embodiment of the present invention; Figure 3 It is a schematic diagram of assembling a slider and a connecting rod according to an embodiment of the present invention; Figure 4 This is a schematic diagram of assembling the pen clip and the pen holder according to an embodiment of the present invention; Figure 5 It is a schematic diagram of assembling the pen clip and the metal spring sheet according to an embodiment of the present invention; Figure 6It is a structural schematic diagram of the connecting section of the pen holder according to an embodiment of the present invention; Figure 7 It is a partial cross-sectional view of the embodiment of the present invention in a core-shrinking state; Figure 8 It is a partial cross-sectional view of the core-out state of an embodiment of the present invention; Fig. 9 It is a partial cross-sectional view of the first locking state of the counterweight block corresponding to the embodiment of the present invention; Fig.10 It is a partial cross-sectional view corresponding to the second locking state of the counterweight block according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The structure of the pen with automatically retractable refill according to the embodiment of the present invention is as follows: Figure 1-10 As shown, it includes a pen holder (11, 12, 13), a pen core 2 arranged in the pen holder, and a pen core self-locking mechanism. The pen core self-locking mechanism is supported at the rear end of the pen core 2 and can move along the front-to-back direction of the pen. A first spring 3 is arranged between the front end of the pen core 2 and the pen holder. The pen core self-locking mechanism includes a sleeve 41, a connecting rod 42, a counterweight 43, a slider 44, and a second spring 45. A window 411 is arranged on the side of the sleeve 41. The slider 44 is arranged at the window 411 of the sleeve 41 for transverse movement. The front end of the connecting rod 42 moves along the front-to-back direction. It is penetrated through the inner side of the sleeve 41 and is connected to the slider 44 in transmission. The rear end of the connecting rod 42 is connected to the counterweight 43. The second spring 45 acts between the sleeve 41 and the connecting rod 42 and is used to drive the connecting rod 42 to move backward relative to the sleeve 41. When the connecting rod 42 moves forward and backward relative to the sleeve 41, it can drive the slider 44 to move outward and inward along the window 411 of the sleeve 41 respectively. When the slider 44 is extended, it abuts against the inner wall of the pen barrel. A limiting portion is provided on the inner side of the pen barrel to limit the position of the front end of the sleeve 41.

[0020] When the writing tool is needed, the pen is placed vertically, and the refill self-locking mechanism and the refill 2 move forward under the action of gravity against the elastic force of the first spring 3, so that the refill 2 extends out from the front end of the pen holder. When the refill self-locking mechanism moves forward, when the front end of the sleeve 41 moves to a position where the sleeve 41 is limited by the limiting portion, the counterweight 43 and the connecting rod 42 move forward relative to the sleeve 41 under the action of gravity against the elastic force of the second spring 45, and at the same time drive the slider 44 to extend outward laterally along the window 411 of the sleeve 41, and the slider 44 and the inner wall of the pen holder form abutment. During the writing process, due to the slider 44 There is damping when it abuts against the inner wall of the pen barrel, which can lock the pen core 2 in the core-out position and prevent the pen core 2 from moving backward due to writing pressure; when the pen is not in use, the pen is placed horizontally, and the gravity direction of the pen core 2 and the pen core self-locking mechanism is no longer in the same direction as the elastic force direction of the first and second springs 45. The counterweight block 43 and the connecting rod 42 move backward relative to the sleeve 41 under the action of the second spring 45, so that the slider 44 retracts laterally inward, releasing the lock between the pen barrel, and the pen core and the pen core self-locking mechanism move backward as a whole under the action of the first spring 3, realizing the automatic core retraction function.

[0021] Compared with the prior art, the above-mentioned solution for realizing automatic extension and retraction of the pen core has fewer parts, a simpler structure, and relatively simple assembly and processing of the parts. It is also highly reliable and is not prone to jamming.

[0022] like Figure 2 , 3 As shown, the slider 44 includes a sleeve portion 441 and an abutment portion 442. The abutment portion 442 is arranged on one side of the sleeve portion 441. The sleeve portion 441 and the connecting rod 42 form a movable sleeve fit. Inclined guide grooves 443 are symmetrically arranged on both sides of the sleeve portion 441. The guide grooves 443 penetrate the inner and outer sides of the sleeve portion 441. The connecting rod 42 is provided with a convex shaft that cooperates with the guide grooves 443 to form a guiding movement. When the connecting rod 42 moves back and forth relative to the slider 44, the slider 44 moves laterally through the convex shaft and the guide groove 443. The connecting rod 42 is provided with a connecting hole 421. The convex shaft is composed of two ends of a metal rod 422 fixedly inserted in the connecting hole 421. When assembling, the connecting rod 42 is first inserted into the sleeve portion 441, and then the metal rod 422 is inserted into the connecting hole 421 of the connecting rod 42 along the guide groove 443 for installation and positioning. The structure is simple and the assembly is convenient.

[0023] An annular retaining wall 412 is provided on the inner side of the sleeve 41 near the rear end, and an active cavity is formed between the rear end of the sleeve 41 and the annular retaining wall 412. A connecting block 423 is provided at the rear end of the connecting rod 42, and the connecting block 423 is movably arranged in the active cavity. The connecting rod 42 is connected and cooperated with the front end of the counterweight block 43 through the connecting block 423. The second spring 45 is sleeved on the connecting rod 42 and abuts against the annular retaining wall 412 and the connecting block 423 respectively. The overall structure is simple and compact, which ensures the stability of the force direction of the second spring 45.

[0024] The rear end of the connecting block 423 is provided with a plug-in hole, and the front end of the counterweight block 43 is provided with a plug-in block that cooperates with the plug-in hole for plugging and positioning, so as to achieve fixed cooperation between the counterweight block 43 and the connecting rod 42, and can prevent the counterweight block 43 from shaking; the front end of the sleeve 41 is provided with a positioning hole that cooperates with the rear end of the pen core 2 for plugging and positioning, so as to achieve relative fixation between the sleeve 41 and the pen core 2 and improve the cooperation effect.

[0025] like Figure 1 , 6 As shown in Figures 7 and 8, the pen holder includes a front section 11, a rear section 13 and a connecting section 12. The front end of the connecting section 12 is screwed to the rear end of the inner hole of the front section 11, and the rear end of the connecting section 12 is inserted and positioned at the front end of the inner hole of the rear section 13. The limiting portion is formed by the rear end of the connecting section 12 (for limiting the farthest distance of the sleeve 41 moving forward). The circumferential limiting portion between the rear end side of the connecting section 12 and the side wall of the inner hole of the rear section 13 is matched with a sliding groove and a convex strip 121 arranged along the front and rear directions of the pen. When installing, the rear end of the connecting section 12 can be first inserted into the rear end of the pen holder. In section 13, when the rear section 13 is operated to rotate relative to the front section 11, due to the circumferential limitation of the connecting section 12 and the rear section 13, the screw connection between the front end of the connecting section 12 and the front section 11 can be achieved, and the operation is relatively convenient. The axial limitation between the rear end side of the connecting section 12 and the side wall of the inner hole of the rear section 13 is coordinated with two annular ribs arranged along the circumference of the pen. The connecting section 12 cooperates with the pen holder through the annular rib 122 on its rear end side to form an axial limitation (i.e., limitation along the length direction of the pen), which can prevent the rear end of the connecting section 12 from slipping forward from the inner hole of the rear section 13.

[0026] The front part of the pen body is provided with a cylindrical weight 5 (including a ring), which is arranged inside the pen body and sleeved on the outside of the pen core 2. The cylindrical weight 5 can be a spirally wound metal wire, such as Figure 1 , 7 , 8. The cylindrical weight 5 is provided to adjust the center of gravity of the writing tool and improve the writing feel.

[0027] like Figure 4 , 5, 9, 10, a pen clip 6 is provided at the rear end side of the pen barrel (i.e., the rear section 13), and the pen clip 6 can move forward and backward within a certain range relative to the pen barrel, a clamping member 7 is movably provided between the pen clip 6 and the pen barrel, and an opening 131 is provided on the side of the pen barrel. When the pen clip 6 moves forward relative to the pen barrel, it can drive the clamping end 71 of the clamping member 7 to extend into the inner side of the pen barrel along the opening 131, and when it moves backward, the clamping end 71 is retracted along the opening 131. The front and rear sides of the counterweight block 43 both include a positioning portion that can form a clamping and positioning match with the clamping end 71 of the clamping member 7 when it extends into the inner side of the pen barrel. In this embodiment, the front edge of the counterweight block 43 serves as the positioning portion of its front side, and the annular groove 431 provided in the middle of the counterweight block 43 serves as the positioning portion of its rear side. When the clamping end 7 of the clamping member 7 and the positioning portion of the counterweight block 43 are engaged with each other, the counterweight portion 43 can be kept at the current position, such as Fig. 9 As shown, when the counterweight 43 is in the rear position (the position corresponding to the core-retracted state), the front edge of the counterweight 43 is clamped and positioned by the clamping end 71. Since the pen clip 6 is in the front position and cannot move forward, the counterweight 43 cannot move forward. Fig.10 As shown, when the counterweight 43 is in the front position (the position corresponding to the core-out state), the clamping end 71 is clamped and positioned with the annular groove 431 of the counterweight 43. Since the pen clip 6 is in the rear position and cannot continue to move backward, the counterweight 43 cannot move backward, so that the pen core 2 can be kept in the core-out or core-retracting position, so that it is not affected by the posture of the pen, that is, whether it is placed vertically or horizontally, the pen core can be prohibited from automatically extending or retracting, especially when carrying a pen, it can prevent the pen core 2 from automatically extending, play a certain protective role for the pen core 2, and also prevent it from soiling other items in the bag. In addition, it can also increase the tilt angle of the pen when writing to prevent the pen core from automatically retracting.

[0028] The clamping member 7 is a metal spring arranged between the pen clip 6 and the pen barrel. One end of the metal spring is a clamping end 71, and the other end is a fixed end 72. A curved portion 73 is formed between the clamping end 71 and the fixed end 72. The fixed end is fixed to the inner side of the pen clip 6. A recess 8 is formed between the pen clip 6 and the pen barrel for the curved portion 73 of the metal spring to be placed. The recess 8 is arranged at a position close to the opening 131 on the side of the pen barrel. The recess 8 includes a side wall adjacent to the opening 131. The clamping end 71 forms an elastic compression fit with the side wall. When the pen clip 6 moves forward and backward relative to the pen barrel, it can also drive the metal spring to move forward and backward relative to the pen barrel. Since the clamping end 71 of the metal spring is pressed and contacted with the side wall of the recess 8, it can move along the side wall with the movement of the pen clip 6. When it moves forward to the opening 131, it extends into the inner side of the pen barrel under the action of its own elasticity and can cooperate with the counterweight 43 (such as Fig. 9 , 10 status shown).

[0029] The side wall of the notch 8 is provided with a positioning rib 81, and the clamping end 71 is provided with a positioning groove 711 that cooperates with the positioning rib 81. Through the cooperation between the positioning rib 81 and the positioning groove 711, the metal spring and the pen barrel can be positioned, and then when the pen clip 6 moves backward to the end position, the pen clip 6 and the pen barrel are positioned to prevent the pen clip 6 from shaking.

[0030] The above embodiment is only one of the preferred specific embodiments of the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention are all included in the protection scope of the present invention.

Claims

1. A pen with an automatically retractable refill, comprising a pen holder, a refill arranged in the pen holder, and a refill self-locking mechanism, wherein the refill self-locking mechanism is supported at the rear end of the refill and can move in the front-rear direction of the pen, and a first spring is arranged between the front end of the refill and the pen holder, characterized in that: The pen core self-locking mechanism includes a sleeve, a connecting rod, a counterweight, a slider, and a second spring. A window is provided on the side of the sleeve. The slider is arranged at the window of the sleeve for transverse movement. The front end of the connecting rod is movably arranged in the inner side of the sleeve along the front-back direction and is connected and matched with the slider for transmission. The rear end of the connecting rod is connected with the counterweight. The second spring acts between the sleeve and the connecting rod and is used to drive the connecting rod to move backward relative to the sleeve. The connecting rod and the sleeve form a guiding movement cooperation through the convex shaft and the inclined guide groove therebetween, so that when the connecting rod moves forward and backward relative to the sleeve, it can drive the slider to move laterally outward and inward along the window of the sleeve respectively. When the slider is extended, it forms an abutment cooperation with the inner wall of the pen barrel. A limiting portion that cooperates with the front end of the sleeve for limiting the position is provided on the inner side of the pen barrel; a counterweight for balancing the center of gravity is provided at the front of the pen barrel.

2. The pen with automatically retractable refill according to claim 1, characterized in that: The sliding block includes a sleeve portion and an abutment portion, wherein the abutment portion is arranged at one side of the sleeve portion, the sleeve portion and the connecting rod form a movable sleeve fit, the guide groove is arranged at the side of the sleeve portion, and the convex shaft is arranged on the connecting rod.

3. The pen with automatically retractable refill according to claim 2, characterized in that: Guide grooves are symmetrically arranged on both sides of the sleeve connection part, and the guide grooves penetrate the inner and outer sides of the sleeve connection part. A connecting hole is arranged on the connecting rod, and the convex shaft is composed of two ends of a metal rod fixedly inserted in the connecting hole.

4. The pen with automatically retractable refill according to claim 1, characterized in that: An annular retaining wall is arranged on the inner side of the sleeve near the rear end, and an active cavity is formed between the rear end of the sleeve and the annular retaining wall. A connecting block is arranged on the rear end of the connecting rod, and the connecting block is movably arranged in the active cavity. The connecting rod is connected and cooperated with the front end of the counterweight block through the connecting block, and the second spring is sleeved on the connecting rod and respectively abuts and cooperates with the annular retaining wall and the connecting block.

5. The pen with automatically retractable refill according to claim 4, characterized in that: The rear end of the connection block is provided with a plug hole, the front end of the counterweight block is provided with a plug block that cooperates with the plug hole for plugging and positioning; the front end of the sleeve is provided with a positioning hole that cooperates with the rear end of the pen core for plugging and positioning.

6. The pen with automatically retractable refill according to claim 1, characterized in that: The pen shaft includes a front section, a rear section and a connecting section, the front end of the connecting section is screwed to the rear end of the inner hole of the front section, the rear end of the connecting section is inserted and positioned at the front end of the inner hole of the rear section, the limiting portion is composed of the rear end of the connecting section, the rear end side of the connecting section and the side wall of the inner hole of the rear section are circumferentially limited by sliding grooves and convex strips arranged along the front and rear directions of the pen, and the rear end side of the connecting section and the side wall of the inner hole of the rear section are axially limited by two annular convex ribs arranged along the circumference of the pen.

7. The pen with automatically retractable refill according to claim 1, characterized in that: The counterweight is a cylindrical counterweight, which is arranged on the inner side of the pen holder and sleeved on the outer side of the pen core.

8. The pen with automatically retractable refill according to claim 1, characterized in that: A pen clip is arranged on the rear end side of the pen barrel, and the pen clip can move forward and backward relative to the pen barrel. A clamping piece is movably arranged between the pen clip and the pen barrel, and an opening is arranged on the side of the pen barrel. When the pen clip moves relative to the pen barrel, the clamping end of the clamping piece can be driven to extend into the inner side of the pen barrel or retract along the opening. The front and rear sides of the counterweight block both include positioning parts that can form a clamping and positioning cooperation with the clamping end of the clamping piece when the clamping end extends into the inner side of the pen barrel.

9. The pen with automatically retractable refill according to claim 8, characterized in that: The clamping piece is a metal spring sheet arranged between the pen clip and the pen barrel, one end of the metal spring sheet is a clamping end, and the other end is a fixed end, a bent portion is formed between the clamping end and the fixed end, and the fixed end is fixed to the inner side of the pen clip, and a recess is formed between the pen clip and the pen barrel for the bent portion of the metal spring sheet to be inserted, and the recess is arranged at a position close to the opening on the side of the pen barrel, and the recess includes a side wall adjacent to the opening, and the clamping end and the side wall form an elastic compression fit.

10. The pen with automatically retractable refill according to claim 9, characterized in that: The side wall of the notch is provided with a positioning convex rib, and the clamping end is provided with a positioning groove which cooperates with the positioning convex rib for positioning.

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