JP5416632B2 - mechanical pencil - Google Patents

Description

  The present invention relates to a mechanical pencil capable of feeding a lead by shaking a shaft cylinder up and down.

  A mechanical pencil is widely used in which the weight body stored in the shaft cylinder is moved up and down to move the chuck part forward (toward the tip of the shaft cylinder), or the chuck part is advanced by a knocking operation so that the core is extended. (For example, refer to Patent Document 1). Generally, such a mechanical pencil has a chuck fixed to the front end of a lead tank that is housed in an axial cylinder so as to be movable in the axial direction, and the lead tank is urged rearward by a chuck spring. A protrusion is formed on the attached connector, and a weight body is slidably fitted on the outer periphery of the core tank so as to contact the protrusion. On the other hand, a clip holder formed separately from the lead tank is inserted and fixed behind the lead tank, and an eraser support is provided on the clip holder so as to be movable in the axial direction, and an eraser and a knob are attached to the eraser support. A knock spring is provided between the flange portion and the clip holder to urge the eraser support backward.

  With the above configuration, when the shaft cylinder is moved up and down, the weight body hits the protrusion of the lead tank, and the lead tank can be advanced to feed the lead. Further, when the eraser support is knocked via the knob, the inner end of the eraser support hits the rear end of the lead tank, and the lead tank can be advanced to feed the lead. As described above, the conventional mechanical pencil of this type is configured to feed the lead by always moving the whole lead tank forward when the lead is drawn.

  Due to the above configuration, the conventional mechanical pencil requires a separate clip holder and eraser support in addition to the core tank, which increases the number of parts and chucks from the front end side of the shaft cylinder. And a mechanism that incorporates a chuck spring, connector, etc. must be inserted, and a clip holder part that incorporates an eraser support and knock spring must be inserted and fixed from the rear end side. There was a problem that it was difficult to obtain economically.

Japanese Patent No. 4293803 (FIG. 1)

  The problem to be solved by the present invention is to reduce the number of parts and to assemble almost all of the assembly processes in a mechanical pencil that is fed out by swinging the shaft cylinder up and down or knocking the core tank protruding from the rear end of the shaft cylinder. It is to provide a mechanical pencil which can be easily assembled by being inserted and fixed from the rear end of a shaft cylinder.

  According to the present invention, a lead tank accommodated in the shaft cylinder so as to be movable in the axial direction, a knock spring provided between the front portion of the lead tank and the inner surface of the shaft cylinder so as to bias the lead tank rearward, A weight body loosely fitted around the lead tank so as to be movable in the axial direction, a chuck guide to which a chuck that holds the lead held by the lead tank so as to be moved by the lead tank is fixed, and the chuck guide A chuck spring provided between the front portion of the chuck guide and the inner surface of the shaft cylinder so as to bias it backward with a weak force, and a window formed on the shaft cylinder to limit the backward movement of the core tank. The chuck guide has an engaging projection, and the chuck guide moves in an axial direction so that the weight body can come into contact with the weight body when it moves forward and moves forward independently of the core tank by the weight body. Connected to the core tank Mechanical pencil, characterized in that it has been provided, the problems are solved.

  According to the present invention, the chuck guide has an inner cylinder and an outer cylinder facing each other with an insertion gap into which the core tank wall enters, and a connecting piece for connecting the inner cylinder and the outer cylinder. A receiving groove into which the connecting piece enters is formed, and a play gap is formed between the receiving groove and the connecting piece of the chuck guide when the lead tank is retracted, and the lead tank has a shock absorbing piece. A mechanical pencil is provided.

  The present invention is configured as described above, and is provided between a front portion of the lead tank and the inner surface of the shaft tube so as to urge the lead tank rearward so as to be axially movable in the shaft tube. A chuck guide to which a knock spring, a weight body loosely fitted around the lead tank so as to be movable in the axial direction, and a chuck for holding the lead held by the lead tank so as to be moved by the lead tank are fixed. A chuck spring provided between the front portion of the chuck guide and the inner surface of the shaft cylinder so as to urge the chuck guide rearward with a weak force, and a shaft cylinder provided in the core tank to limit the backward movement of the core tank The weight guide contacts the chuck guide when the weight body moves forward, and the chuck guide moves forward independently of the lead tank by the weight body. Move in the axial direction Since the chuck guide is connected to the core tank, the chuck guide can be advanced by moving the shaft cylinder up and down, and the core can be fed out. It is easy to assemble by simply inserting it from the rear end. Like this type of conventional mechanical pencil, in addition to the lead tank, a clip holder and eraser support can be prepared separately. Since the clip holder part does not have to be assembled from the rear part of the shaft cylinder after the part is incorporated, the configuration is remarkably simplified and the assembly can be obtained easily and economically.

  In addition, an inner cylinder and an outer cylinder facing each other with an insertion gap through which the core tank wall enters the chuck guide and a connecting piece for connecting the inner cylinder and the outer cylinder are provided, and a receiving groove for entering the connecting piece into the core tank is provided. When the eraser or the like attached to the rear part of the lead tank is used, a lead tank is formed between the receiving groove and the connecting piece of the chuck guide. Even if it is pressed slightly forward, the chuck guide is not moved, and the core can be prevented from inadvertently protruding. In addition, if a shock absorbing piece is provided in the core tank, and the standing piece is raised on the outer surface of the core tank as the shock absorbing piece, the structure of the shock absorbing piece is simple, and no separate parts or assembly steps are required. Can be obtained more economically.

BRIEF DESCRIPTION OF THE DRAWINGS The front view which partially showed the one Example of this invention and was partially cut. The core tank is shown, (A) is a front view partially cut in half, (B) is a side view as seen from the front end side of the core tank, (C) is a sectional view of the locking projection, and (D) is shock absorption. Sectional drawing of one part. The case where the lead tank is attached to the shaft cylinder is shown. (A) is a state where the lead tank is inserted into the shaft cylinder, and (B) is a state where the lead tank is inserted to the position where the locking projection is engaged with the window of the shaft cylinder. Each explanatory drawing. A chuck guide is shown, (A) is a front view with a half section, (B) is a front view with a half section of a part rotated 90 degrees from the position (A), (C) is (A). (D) is sectional drawing of a connection piece part. The exploded perspective view of a chuck guide part. Explanatory drawing when extending a lead by knocking operation. Explanatory drawing in the case of extending a lead by a vertical movement operation. Explanatory drawing which shows one Example which attached the eraser unit.

  FIG. 1 shows an embodiment of the mechanical pencil of the present invention. A taper 3 provided with a temporary core holding mechanism 2 such as a breaker rubber or an elastic holding piece is connected to the front end of the shaft cylinder 1. The cylindrical core tank 4 is accommodated so as to be movable in the axial direction. As shown in FIG. 2 (A), two insertion pieces 6 are formed at the front portion of the core tank 4 by facing the receiving grooves (split grooves) 5. A knock spring 9 for urging the core tank 4 rearward is provided between the provided spring receiver 7 and the step portion 8 formed on the inner surface of the shaft tube. In the embodiment shown in the drawing, the spring receiver is formed as a small projecting piece, but may be a recessed portion, and the number of insertion pieces can be appropriately formed. The knock spring load is set to a high load of about 500 g, for example.

  A locking protrusion 11 is provided on the enlarged diameter portion 10 formed at the rear portion of the core tank 4. As shown in FIG. 3, when the core tank is inserted into the shaft tube, the locking projection 11 is inserted into the shaft tube so as to easily protrude into an axially extending window 12 formed in the shaft tube. An inclined surface 13 is formed on the rear end, and a standing surface 15 is formed at the rear end so as to reliably engage the edge portion 14 of the window 12 and limit the backward movement when the lead tank is retracted. Further, when the core tank is inserted from the rear end of the shaft cylinder and attached to the shaft cylinder, the core tank 4 bends inward so that the locking projection 11 can easily protrude into the window 12. A relief hole 16 for allowing the deflection of the lead tank 4 is formed in the enlarged diameter portion 10, and an impact absorbing piece 17 is formed integrally with the lead tank at an intermediate portion of the lead tank slightly ahead of the enlarged diameter portion. The raised piece is projected. An eraser 18 is fitted to the rear end of the enlarged diameter portion 10 of the core tank 4.

  Around the core tank 4, a weight body 19 made of a cylindrical metal pipe or the like is loosely fitted so as to move in the axial direction when the shaft cylinder 1 is moved up and down. An impact absorbing piece 17 such as the standing piece is provided in front of the enlarged diameter portion 10 of the core tank 4 so as to absorb and mitigate the impact when the weight body 19 comes into contact. In addition, a member formed separately from the core tank with an elastic material such as a rubber material or an elastomer material can be attached to the core tank to absorb the impact. As shown in FIG. 2, when the above-mentioned standing piece that rises integrally from the outer surface of the core tank is provided, when the weight hits the standing piece, the tip of the standing piece is slightly elastically inclined to give an impact. Since it can be absorbed, the number of parts is reduced and assembly is facilitated, which is more preferable.

  A chuck guide 20 is attached to the front portion of the lead tank 4 so as to be movable in the axial direction. Referring to FIG. 4, the chuck guide 20 has an inner cylinder 21 facing the inner surface of the core tank 4 and an insertion gap 22 into which the core tank wall enters between the inner cylinder 21 and the chuck tank 20. An outer cylinder 23 facing the outer surface, and a connecting piece 24 having a width for connecting the inner cylinder 21 and the outer cylinder 23 and entering the receiving groove 5 of the core tank 4 are formed. A through hole 25 is provided so that the insertion piece 6 formed in the front portion of the core tank 4 passes through, and the chuck guide 20 is urged backward between the step portion 8 formed in the inner surface of the shaft cylinder 1. A chuck spring 26 is provided. With this configuration, the chuck guide 20 can be moved in the axial direction along the insertion piece 6. Preferably, the core guide is mounted so that the weight body is lightly applied to the chuck guide by its own weight after being mounted on the core tank 4 during assembly. A raised portion 27 is formed on the outer periphery of the insertion piece 6 extending forward through the through hole so as to engage with the edge of the through hole so as not to easily come off from the tank. Has been. For this purpose, the insertion piece is inserted into the through-hole while the bulging portion is pushed inward, and after the penetration, the bulging portion returns to its original state by the elastic action so that it can be engaged as described above. do it.

  A chuck fixing portion 30 is formed on the front inner surface of the inner cylinder 21 of the chuck guide 20 so that the base end of the chuck 29 fitted with the clutch 28 can be inserted and fixed. When the chuck guide 20 moves backward, the clutch 28 is locked to the inner tip of the shaft tube 1 as is well known, and tightens the chuck 29. Further, a support surface 31 is formed at the front end portion of the outer cylinder 23, and the chuck spring 26 provided between the support surface 31 and the stepped portion 8 of the shaft cylinder contacts the support surface 31 as described above. The chuck spring 26 is a spring having a weaker force than the knock spring 9, and is set to a low load of about 150 g, for example. A contact surface 32 is formed at the rear end portion of the outer cylinder 23 so that the weight body 19 contacts.

  With the above configuration, the chuck spring 26 and the knock spring 9 are inserted into the shaft cylinder from the rear end of the shaft cylinder, and the weight body 19 is loosely fitted to the intermediate portion of the core tank 4 and the insertion piece 6 formed at the front portion is formed. The chuck guide 20 is inserted into the core tank 4 through the through hole 25 of the chuck guide 20, the core tank assembly is inserted from the rear end of the shaft cylinder, and the locking projection 11 is engaged with the window 12. Then, the assembly is finished. Thereafter, the chuck 29 may be inserted into the chuck guide 20 from the front of the shaft tube, or the eraser 18 and the taper 3 may be attached. As described above, since most of the processes can be performed from the rear end side of the shaft tube, the assembly is easy. When the lead tank is retracted in the assembled state, a slight play gap S is formed between the connecting piece 24 of the chuck guide 20 and the bottom 33 of the receiving groove 5 of the lead tank 1 as shown in FIG. It is supposed to occur. The play gap S is such that when the eraser 18 provided at the rear end of the lead tank 4 is used as usual, the bottom 33 of the receiving groove does not hit the connecting piece 24 to the extent that the lead tank 4 is pushed slightly forward. The dimensions should be as follows.

  And in order to let out the lead 34 by knocking operation, as shown in FIG. 6, when the rear end of the lead tank 4 is knocked forward like a normal mechanical pencil, the lead tank 4 is resisted against the knock spring 9. It moves forward, the bottom 33 of the receiving groove comes into contact with the connecting piece 24 of the chuck guide 20, and the chuck guide 20 moves forward against the chuck spring 26. Therefore, the chuck 29 fixed to the chuck guide 20 moves forward and is known. The core 34 can be extended as shown in FIG. When the knocking is stopped, the lead tank moves backward, but this backward movement is restricted by the locking projection 11 hitting the edge 14 of the window 12. When the lead 34 is retracted, the tip of the lead 34 may be pushed back into the taper 3 while knocking the lead tank 4 as is well known.

  When the shaft cylinder 1 is moved up and down, as shown in FIG. 7, the weight body 19 moves forward and hits the contact surface 32 provided at the rear end portion of the outer cylinder 23 of the chuck guide 20. Can be advanced against the chuck spring 26, so that the lead 34 is fed out as in the case of the knocking operation. In this case, since the chuck guide 20 is independent from the lead tank 4, the lead tank 4 does not move forward, and only the chuck guide 20 moves.

  When the weight body 19 moves up and down in the shaft cylinder 1 to a position where it hits the enlarged diameter portion 10 of the core tank 4, it strikes the impact absorbing piece 17 provided in front of the enlarged diameter portion. Can be prevented from giving a large impact that would cause the to come off. Therefore, as shown in FIG. 8, even if the eraser unit 35 of the feeding type and other appropriate members are attached to the rear end portion of the core tank 4, the eraser unit 35 and the like are not detached due to vibration, impact, or the like. be able to.

DESCRIPTION OF SYMBOLS 1 Shaft cylinder 3 Taper 4 Core tank 5 Receiving groove 6 Insertion piece 9 Knock spring 10 Expanding part 11 Locking protrusion 12 Window 17 Shock absorption piece 19 Weight body 20 Chuck guide 21 Inner cylinder 22 Insertion gap 23 Outer cylinder 24 Connection piece 25 Through hole 26 Chuck spring 29 Chuck 30 Chuck fixing part

Claims (8)

  A core tank accommodated in the shaft cylinder so as to be movable in the axial direction, a knock spring provided between the front portion of the core tank and the inner surface of the shaft cylinder to urge the core tank rearward, and around the core tank A weight body loosely fitted so as to be movable in the axial direction, a chuck guide fixed to a chuck that holds the lead held by the front of the lead tank so as to be moved by the lead tank, and the chuck guide is moved backward with a weak force. A chuck spring provided between the front portion of the chuck guide and the inner surface of the shaft cylinder so as to be biased, and a locking projection provided on the core tank and engaged with a window formed on the shaft cylinder to limit the backward movement of the core tank. The chuck guide is attached to the core tank so that the weight body can come into contact with the weight body when it moves forward, and can move in the axial direction so as to move forward independently of the core tank by the weight body. Specially connected Sharp pencil to be.   An insertion piece is formed at the front portion of the core tank, and the chuck guide has a through hole through which the insertion piece is movably penetrated, and the tip of the insertion piece extends forward through the through hole. The mechanical pencil according to claim 1, wherein a spring receiving portion is formed, and the knock spring is inserted between the spring receiving portion and the inner surface of the shaft tube.   The insertion piece of the core tank is formed by a receiving groove extending in the axial direction, and the chuck guide has an inner cylinder facing the inner surface of the core tank and an insertion gap into which the core tank wall enters between the inner cylinder. And an outer cylinder facing the outer surface of the core tank, and a connecting piece that connects the inner cylinder and the outer cylinder and has a width that enters the receiving groove, and the through hole is formed in the front portion of the insertion gap. The mechanical pencil according to claim 2.   The mechanical pencil according to claim 3, wherein when the core tank is moved rearward by a knock spring, a play gap is formed between the bottom of the receiving groove and the connecting piece.   The chuck is fixed to the inner cylinder of the chuck guide, a contact surface with which the weight body contacts is formed at the rear end of the outer cylinder, and a support surface with which the chuck spring contacts is formed at the front end. The mechanical pencil according to claim 3 or 4, wherein the mechanical pencil is formed.   The mechanical pencil according to claim 1, wherein an escape hole is formed in the core tank so as to allow the core tank to bend when the locking protrusion is locked to the window.   The mechanical pencil according to any one of claims 1 to 6, wherein an impact absorbing piece is provided on the core tank so that a weight body comes into contact therewith.   The mechanical pencil according to claim 7, wherein the shock absorbing piece is an upright piece erected on the outer surface of the lead tank.

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