JP2557063Y2 - mechanical pencil - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a mechanical pencil for lower grade children and for examinations. ＾

[0002]

2. Description of the Related Art Conventionally, a rear shaft is rotated with respect to a front shaft to feed a large-diameter eraser from a rear end of the rear shaft, and a rear shaft is knocked at a rear end of the front shaft to feed a core. Mechanical pencils are known. This object has the trouble of knocking the rear end frequently with the consumption of the core. In addition, there is an annoyance that the eraser projecting when knocking is stored in the rear shaft. (If you knock in the protruding state, your finger gets dirty, and there is a problem that the oil of your finger is transferred to the end surface of the eraser and the erasure is deteriorated.)

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide a mechanical pencil which is convenient for children of lower grades and for examinations.

[0004]

In order to achieve the above object, the mechanical pencil according to the present invention is provided with a lead case having a chuck fixed to the tip in a tip shaft so that the chuck can be moved in the axial direction. Attaching a chuck spring that rebounds with a weak force to the rear, a weight that can be fitted to the core case between the tip and the rear end of the core case and that can be shifted by its own weight is arranged, and an eraser at the rear end of the front shaft It is a convenient mechanical pencil with a detachable body. The eraser dispensing body has a cap with a spiral groove in the inner hole, an inner cylinder with a slit, rotatably fastened in the cap inner hole, and at least a constant forward movement of the inner cylinder through the elasticity of the return spring. It is movable only in the axial direction within the range, and it is fixed so that retraction is appropriately prevented at the most advanced position, and is detachably attached to the rear end of the front shaft. An eraser holder having an eraser fixed to an end is formed by fitting a projection into a slit and a spiral groove in the inner cylinder, and is provided so that the axial movement of the inner cylinder is interlocked with the lead case and the chuck. As described above, the chuck is axially moved by the inertia force of the weight by shaking the shaft, and the core is fed out. By rotating the cap with respect to the front shaft, the eraser is configured to be able to come and go from the rear end. . Therefore, the core can be extended without knocking the rear end, so that there is no need to frequently put the eraser in and out. Further, when the cap is held at the most advanced position with respect to the front shaft, the gripping of the lead by the chuck is released, so that there is no inconvenience that the lead is swung when the user carries the portable device.

[0005]

1 and 2 show a first embodiment of the present invention. First, a tip pipe 9 through which a wick can be inserted is fixed to the tip of the base 7, and a holding chuck 10 made of rubber or the like through which the wick is appropriately frictionally engaged and inserted is fixed to the end of the inner hole. Further, a screw portion (female screw) having a step portion 8 at the end is provided behind the inner hole of the base 7.

The front shaft 1 is provided with a shaft portion 2 having a screw portion 5 (male screw) at the tip of a cylindrical body, and the shaft portion 2 is provided with a hole having a front stage 6, and the hole is formed in the rear. Of the cylindrical body. Also, a step 3 is provided at the tip of the inner hole,
On the rear end inner wall of the inner hole portion, a shape is formed integrally with a later-described joining cylinder 34 and a projection 4 for retaining and locking in a rotational direction.

A chuck 14 is fitted into the hole of the shaft 2 of the front shaft by engaging the head with a fastener 15, and a core case 11 is inserted into an inner hole of the front shaft 1. The rear end of the chuck 14 is fixed to the front end of the chuck 11. At this time, the step portion 3 at the tip of the inner hole portion and the collar portion 1 provided substantially at the tip of the core case 11 are provided.
2, a chuck spring 16 is urged.
Note that the chuck spring 16 rebounds the chuck 14 rearward with an appropriate weak force. The lead case 11 is a cylindrical body provided with a lead storage portion through which a lead can be inserted into the chuck 14, and a flange portion 18 is formed at a rear end of the lead case 11 with a slit 19 at an appropriate position. A cushioning material 13 such as rubber is fixed to the outer periphery of the leading end of the lead case 11 in contact with the rear end of the flange portion 12, and a weight 17 is fitted further rearward by elastic deformation of the flange portion 18. The weight 17 can move axially between the cushioning material 13 and the flange portion 18 by its own weight.

In addition, a joint cylinder 34 of an eraser feeding body, which will be described later, is detachably fixed to the rear end hole of the front shaft 1. A groove 41 is formed in the side surface of the shaft portion 35 at the front of the joining cylinder 34, and the protrusion 41 of the rear end hole of the front shaft is elastically passed over and the two are prevented from coming off by appropriate force. Further, a shape is provided on a side surface of the joining cylinder 34 so as to be engaged with the rear end hole of the front shaft 1 and become integral with each other in the rotation direction. Further, as shown in FIG. 2, a vertical groove 38 in which a locking step portion 40 is formed together with an opening having a tapered portion 44 at an appropriate position from the rear end side on the side surface of the shaft portion 36 behind the joining cylinder 34. A lateral groove 39 is provided at a front position (a position at which the inner cylinder moves forward to advance the chuck to release the gripping of the core, as will be described later) in a direction substantially perpendicular to the vertical groove 38. A protrusion 43 is formed on a wall on the rear side of the entrance 39.

The eraser dispensing body is composed of a combination of a cap 20, an inner cylinder 24, an eraser holder 31, and the joining cylinder 34. The cap 20 is fitted on the outer periphery of the rear end of the front shaft 1 in the forward direction. A hole is provided, and a step 22 is formed at the rear end of the inner hole. A clip 23 is provided on the side surface, and a spiral groove 21 is formed on the inner surface. The inner cylinder 24 has a crown 28 at the rear end, which is in contact with the rear end surface of the cap 20, together with a hole through which the eraser 33 is inserted, and a long slit 25 is formed from substantially the center toward the crown. I have. A flange 27 is provided on the rear end side surface of the front shaft portion 26, a projection 29 is formed on the front side surface, and a boss portion 42 having the step portion 30 is further formed on the front side. .

[0010] The eraser dispensing body is configured such that an eraser holder 31 is elastically fitted from a slit 25 of an inner cylinder 24, a projection 32 provided on a side surface thereof is fitted into the slit, and the inner cylinder 24 is attached to a rear end of the cap 20. Then, the projection 32 is inserted into the spiral groove 21 while being fitted into the spiral groove 21, and the flange 27 is substantially brought into contact with the step 22 of the cap 20 by elastic deformation, so that the cap 20 is connected to the crown 28 and the joint cylinder flange 27. It is rotatable with respect to the inner cylinder 24 (having some frictional resistance with the inner cylinder) and is prevented from falling off. An eraser 33 is fixed to the rear end of the eraser holder 31, and a return spring 43 is attached between the flange portion 37 of the joining cylinder 34 and the step 22 of the cap 20, so that the cap 20 and the inner cylinder 2 are removed.
4 is elastically moved rearward, the projection 29 of the inner cylinder 24 is fitted into the vertical groove 38 of the joining cylinder 34 by utilizing the elastic deformation of the shaft 36, and the projection 29 is engaged with the locking step 40. Stop. Therefore, the inner cylinder 24 moves axially with respect to the joining cylinder 34, but is integrated in the rotation direction. Also, the return spring 43
Is urged by the chuck spring 16 with an appropriately stronger force.

In this state, the eraser feeding body is detachably attached to the rear end hole of the front shaft 1. Also, at this time, the boss portion 42 is appropriately fitted in the rear end hole of the core case 11 while the step portion 30 ahead of the shaft portion 26 of the inner cylinder is substantially in contact with the rear end surface of the core case 11. When the rear end collides with the flange portion 18, the flange portion 18 is reduced in diameter and the weight 17 is prevented from coming off. When the cap 20 is rotated with respect to the front shaft 1, the eraser 33 is protruded from the rear end hole of the crown 28.

FIGS. 3 and 4 show a second embodiment of the present invention. The only difference from the first embodiment is the shape of the joining cylinder. The joining cylinder 50 of the present example is provided with a tapered portion 55 from the rear end at an appropriate position on the side surface of the rear shaft portion 51,
2 is formed and a slit 53 is formed.
A protrusion 54 is formed on the side wall of the step 52 at an appropriate position in front of the step 52.

[0013]

First, in order to advance the lead, the weight 17 moves forward by grasping the front shaft 1 and swinging it forward in the axial direction.
The lead case 11 and the chuck 14 are moved forward by the inertia force of the lead to draw out the lead. When returning the core that has protruded too much from the end pipe 9, when the cap 20 is advanced with respect to the front shaft 1, the chuck 14 advances together with the core case 11 in conjunction with the inner cylinder 24, and the fastener 15 is moved from the head of the chuck. When the core is released and gripping of the core is released, and at the same time the tip of the core is pressed against the paper surface or the like, the core returns into the distal end pipe 9. When the cap 20 is rotated with respect to the front shaft 1, the eraser 33 is protruded and retracted from the rear end of the crown 28.

When carrying a mechanical pencil, first, in the first embodiment, a cap 2 is
When 0 is advanced to the maximum and rotated in one direction (the cap and the inner cylinder rotate appropriately in this case because they have appropriate frictional resistance), the protrusion 29 provided on the inner cylinder 24 is inserted into the lateral groove 39, When the advance is released, the rear end of the projection 29 abuts against the rear wall of the lateral groove 39 as shown in FIG. At this time, since the chuck 14 is also in the forward position and the grip of the lead is released, the lead is not extended even if it is shaken. Further, since the projection 29 is prevented from rotating by the protrusion 43 of the lateral groove 39, the rotation of the inner cylinder 24 is stopped. When the core can be extended again, the cap 20 can be inserted into the vertical groove 38 from the horizontal groove 39 by rotating in the opposite direction while pressing the cap 20 against the leading shaft 1 so as to be in the most advanced position. 20 retracts to the state shown in FIG.

In the second embodiment, when the cap 20 is moved forward most with respect to the front shaft 1, as shown in FIG.
The projection 29 of No. 4 elastically passes over the projection 54 of the slit 53 and is locked at the position shown by B, and the chuck 14 is moved to the forward position as in the first embodiment and the gripping of the lead is released. When the core can be extended again, the cap 20 is pulled backward with respect to the front shaft 1 to release the engagement between the projection 29 and the projection 54. The locking force between the projection 29 and the projection 54 is
Even if the shaft is shaken normally, the locking is not released, and the fastening force between the front shaft 1 and the joining cylinder 50 is set to be stronger than the locking force between the projection 29 and the projection 54.

[0016]

[Effect of the Invention] The configuration and operation of the mechanical pencil of the present invention are as described above. The lead can be extended simply by swinging the writing instrument forward in the axial direction. Therefore, it is necessary to knock the rear end every time the lead is extended as in the conventional case. There is no need to change the shaft for knocking and eliminate the hassle of having the eraser appear and disappear.
Therefore, it is excellent as a mechanical pencil for lower grade children and examinees who frequently write and erase. In addition, there is an effect that the lead can be set so as not to be pulled out during carrying.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a mechanical pencil according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing an axial locking relationship between an inner cylinder and a joining cylinder in the first embodiment.

FIG. 3 is a longitudinal sectional view of a mechanical pencil according to a second embodiment of the present invention.

FIG. 4 is an explanatory view showing an axial locking relationship between an inner cylinder and a joining cylinder in a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front shaft 2 Shaft part 3 Step part 4 Projection 5 Screw part 6 Front part 7 Base 8 Step 9 Tip pipe 10 Holding chuck 11 Core case 12 Flange part 13 Buffer material 14 Chuck 15 Fastener 16 Chuck spring 17 Weight 18 Flange part DESCRIPTION OF SYMBOLS 19 Slippery 20 Cap 21 Spiral groove 22 Step 23 Clip 24 Inner cylinder 25 Slit 26 Shaft 27 Flange 28 Crown part 29 Projection 30 Step 31 Eraser holder 32 Projection 33 Eraser 34 Joint cylinder 35 Shaft 36 Shaft 37 Flange Part 38 Vertical groove 39 Horizontal groove 40 Step part 41 Groove 42 Boss part 43 Projection part 44 Taper part 45 Return spring 50 Joining cylinder 51 Shaft part 52 Step part 53 Slit 54 Projection 55 Taper part

Claims (1)

(57) [Scope of request for utility model registration] 1. A lead case having a chuck fixed to a tip thereof is accommodated in a front shaft so as to be axially movable, and a chuck spring for resiliently repelling the chuck with a small force is attached to a space between the tip and the rear end of the lead case. In a mechanical pencil, a weight that can be axially moved by its own weight by being fitted to the lead case is provided and an eraser feeder is detachably attached to the rear end of the front shaft, the eraser feeder has an inner hole. A cap with a spiral groove on the inside, an inner cylinder with a slit and rotatably fixed in the cap inner hole, and an inner cylinder that can move only in the axial direction within at least a certain forward range through the elasticity of the return spring ,
A joining cylinder which is fixed so as to be appropriately prevented from retreating at a substantially most advanced position and which is detachably attached to the rear end of the front shaft, and an eraser having a projection on a side surface and an eraser fixed to the rear end. The holder is configured by fitting its protrusion into the slit and the spiral groove in the inner cylinder, and is provided so that the axial movement of the inner cylinder is interlocked with the core case and the chuck. The mechanical pencil is characterized in that the lead is extended along the axis, and the eraser is made to be able to come and go from the rear end by rotating the cap with respect to the leading axis.