JP4634078B2 - Center feeding device - Google Patents

Description

  The present invention provides a lead feeding device that can project a core of a certain length from the tip of a writing instrument by a knocking operation, and can maintain the projecting core at a certain length even when the knocking operation is repeated, specifically, a mechanical pencil or The present invention relates to an improvement of a lead feeding device used for a writing lead holder or the like.

The structure of a mechanical pencil that has been well known in the past is shown in FIG. 21 and will be described with reference to FIG. As shown in FIG. 21, a chuck 125 is installed at the tip of the shaft cylinder 123 via a shaft coupling 124, and a fastener 126 is fitted on the outer periphery of the gripping portion of the chuck 125. Further, a biased chuck spring 128 is provided between the core case 127 fixed to the rear end of the chuck 125 and the shaft coupling 124. The chuck 125 is clamped by the fastener 126 by the chuck spring 128 to grip the core 129. A slider 131 is fixed to the tip of the tip 130 attached to the tip of the shaft cylinder 123. The slider 131 has a tip pipe 132 fixed to the front of the shaft 131a and a holding chuck 133 made of an elastic material such as rubber fixed to the rear, and the core 129 protrudes from the tip pipe 132 through the holding chuck 133. . From this state, when a knock cover (not shown) attached to the upper end portion of the lead case is pressed (knocked) to advance the chuck 125, the chuck 125 is fastened by the fastener 126. Advance in the gripped state. When the front end of the fastener 126 comes into contact with the stepped portion 130a provided on the tip portion 130 and the chuck 125 further advances, the tightening by the fastener 126 is released. Further, when the chuck 125 further advances, the fastener 126 is locked to the step portion 130a, so that only the chuck 125 advances, and the grip portion at the tip end portion of the chuck 125 is expanded. When the knocked state is released, the core 129 is held by the holding chuck 133, and the chuck 125 is moved backward while the gripping portion of the chuck 125 is further expanded. Then, the chuck 125 starts gripping the core 129 from the state in which the fastener 26 comes into contact with the shaft coupling 124 and the backward movement of the fastener 126 is prevented. Then, when the knocking is finished (initial state), the chuck 125 completes the gripping of the lead 129.
Shokai 55-99887

As described above, in the conventional mechanical pencil, the front end of the fastener 126 comes into contact with the stepped portion 130a every time the knocking operation is repeated, and the front end of the fastener 126 is pivoted. By repeating the state of contacting the joint 124 and being gripped by the gripping portion of the chuck 125, the lead 129 is sequentially fed out.
In the above-described conventional mechanical pencil, the lead is consumed as the writing is performed, so that the lead is sometimes pulled out by knocking. If this knocking operation is forgotten, the lead may be worn down to the front end of the tip pipe 132, the writing may be rubbed, and eventually the paper may be torn at the front end of the hard tip pipe. On the other hand, there are cases where the knocking operation is unnecessarily performed to feed out the lead and the protruding lead is too long, and the problem of breakage of the lead frequently occurs. Also, you may knock unintentionally while writing and get too wicked.

As a means to solve the above-mentioned problems, a writing core holder that can project a core of a certain length from the tip of the writing instrument by a knocking operation and can maintain the protruding core at a certain length even when the knocking operation is repeated is actually opened. This is shown in Japanese Patent Publication No. 55-99887.
The writing core holder will be described with reference to FIGS.
As shown in the figure, a tapered hole 152 into which a chuck 153 that grips the core is fitted is formed at the tip of the shaft tube 151. A tubular core case 154 that houses the core 155 is provided inside the shaft cylinder 151.
An annular protrusion 156 is formed at a substantially intermediate position of the chuck 153. A coil spring 157 is interposed between the annular protrusion 156 and the core case 154, and an upper end of the chuck 153 is slidably mounted in a hole 154a provided in the lower portion of the core case 154. Yes. A coil spring 158 is interposed between the annular protrusion 156 and the upper surface of the shaft cylinder 151 (tapered hole 152). As the coil spring 158, a spring having a stronger repulsive force than the coil spring 157 is used.
A support arm 159 is fixed to the lower peripheral surface of the core case 154. A stopper 160 that fits into the tip of the chuck 153 is formed at the tip of the support arm 159. The operation of the writing core holder configured as described above will be described. First, the cap 161 is removed, the writing core 155 is inserted into the core case 154 and the chuck 153, and the cap 161 is covered (see FIG. 22).
Thereafter, when the cap 161 is knocked, the core case 154 moves downward while compressing the coil spring 157. With this movement, the support arm 159 also moves downward, and the stopper 160 moves away from the tip of the chuck 153 (see FIG. 23). At this time, the upper end of the chuck 153 slides in the hole 154 a of the core case 154. When the cap 161 is further knocked, the lead case 154 moves downward while compressing the coil spring 158. With this movement, the tip (grip) of the chuck 153 expands, and the core 155 drops to the stopper 160 due to its own weight (see FIG. 24).
Thereafter, when the knock of the cap 161 is released (released), the repulsive force of the coil springs 157 and 158 returns the chuck 153 and the support arm 159 to the initial state. At this time, the chuck 153 is closed by fitting into the tapered hole 152 and grips the core 155. Further, since the lead 155 is held by the chuck 153, the lead 155 protrudes from the stopper 160 with a predetermined length (see FIG. 25).
When the cap 161 is knocked again, the core 155 is held by the chuck 153, so that only the support arm moves downward to the state shown in FIG. 24. When the knock is released, the state shown in FIG. 25 is obtained.

As described above, in the proposed writing lead holder, the knocking operation can protrude a fixed length of the lead from the tip of the writing instrument, and even if the knocking operation is repeated, the protruding lead is maintained at a fixed length. be able to.
However, the coil spring 157 urging the stopper 160 rearward and the coil spring 158 urging the chuck 153 rearward are arranged in series with the annular protrusion 156 of the chuck 153 interposed therebetween. Therefore, there is a problem that the protruding length of the core 155 is not stable. For example, when the coil spring 157 urging the stopper 160 is further compressed and the urging force increases and becomes equal to the initial urging force of the coil spring 158 urging the collet chuck 153, the movement of the chuck 153 is performed. Begins, and the chuck 153 begins to expand. That is, there is a possibility that the expansion time of the chuck 153 is delayed due to sliding resistance between the members and other factors, and the protruding amount of the core is not stable.

Further, since the coil spring 157 urging the stopper 160 continues to be compressed after the chuck 153 starts to expand, the stopper 160 continues to advance. As a result, the distance between the stopper 160 that determines the protruding amount of the lead 155 and the tip of the chuck 153 is kept away, and the protruding amount of the lead may not be stable.
Further, the relationship of the urging force of the coil spring in this operation is such that the initial urging force of the coil spring 157 urging the stopper 160 rearward is x1, the urging force when the chuck 153 starts to expand is x2, If the initial biasing force of the coil spring 158 biasing the chuck 153 rearward is y1, the relationship x1 <y1, x2 = y1 is established.
The coil spring 158 that biases the chuck 153 rearward is the same as described above with respect to the biasing force of the coil spring 157 that biases the stopper 160 rearward (the coil spring 158 needs to have a stronger biasing force). As a result, for example, when the lead is thin in a mechanical pencil or the like, the lead may be damaged or damaged by the chuck, so-called messed (broken), and the surface may be roughened (damaged). .
As another operation, when the expansion of the collet chuck 153 starts when the coil spring 157 urging the stopper 160 is fully compressed, the total length of the coil spring 157 at the time of full compression is the variation in wire diameter or It is conceivable that it easily changes due to variations in the number of windings, radial displacement when the coils are closely attached, and the like.
The relationship of the spring urging force in this operation is that the initial urging force of the coil spring 157 urging the stopper 160 rearward is X1, the urging force when fully compressed is X2, and the chuck 153 is rearward. If the initial urging force of the energizing coil spring 158 is Y1, the relationship X1 <Y1 and X2 <Y1 is established.
Even in this operation, the coil spring 158 that urges the chuck 153 rearward is the above-described restriction (the coil spring 158 having a stronger urging force) with respect to the urging force of the coil spring 157 that urges the stopper 160 rearward. As described above, when the lead is thin, the lead 155 is bitten by the chuck 153, and there is a concern that the lead may become rough.
Moreover, in this writing core holder, the use of a member that seems to be extremely difficult is also a problem in realizing this device.
For example, regarding the shaft cylinder 151, it is necessary to provide two through holes 151a (see FIG. 23) for inserting the support arm 159 of the stopper 160 in addition to providing the tapered hole 152 at the tip, which is very difficult to process. It is expected to be a very expensive part because of its shape, low productivity.
Further, since the support arm 159 requires a long distance to the tip of the core case 154 and is inserted through the shaft cylinder 151, it is expected that the thickness and width cannot be sufficiently secured.
Further, the stopper 160 is provided integrally with the support arm 159. However, such a support arm has a shape that is very difficult to process, and it is expected that the productivity will be low and it will be a very expensive part. The Further, this writing core holder has a problem that it is difficult to assemble. For example, the coil spring 158 that urges the chuck 153 rearward is laid between the annular protrusion 156 provided at the center of the chuck 158 and the inner surface of the tip of the shaft cylinder 151, but cannot be assembled as long as it is inferred. It is.
In addition to the above-mentioned problems, the present invention is presumed to be an image in which a thick core is projected so as to have a writing core holder, which is a defective structure for a mechanical pencil structure using a thin core. For example, in the case of a mechanical pencil, the core is thin, and in order to prevent the core from breaking, it is necessary to provide rigidity between the tip protruding from the core and the chuck so as not to cause misalignment. Further, the length of the protrusion of the lead is set to be short in order to prevent breakage of the lead, and the tip of the writing instrument needs to be formed in a tapered shape so that the tip can be easily visually recognized at the time of writing.

The present invention solves the problem of core breakage and the problem of unintentionally knocking during writing and feeding out the core, so that a certain length of core protrudes from the tip of the writing instrument by the knocking operation, and the knocking operation is repeated. This is a lead feeding device in which the lead is maintained at a constant length, the lead protruding length is stable, the tip is easily visible, and it is easy to use. An object of the present invention is to provide a lead-out device that does not have a risk of being bitter.
In addition, when the knock operation part is moved forward most and the lead comes into contact with the contact part of the stopper due to its own weight drop, when the knock operation is released and the knock operation part moves backward, the chuck is released from the lead holding state. There is a phenomenon in which the lead is dragged back by frictional engagement between the lead and the gripping portion of the chuck when the lead is held back, and a minute gap is generated between the contact portion of the stopper and the front end of the lead. Since this phenomenon is in a substantially constant gap state with respect to repeated knocking operations, there is no problem in making the protruding amount of the core constant by allowing for that amount.
However, apart from this phenomenon, there is a phenomenon that the lead is pulled backward when the knocking operation is particularly fast.
This phenomenon is presumed to be the effect that the air pressure in the lead case fluctuates when the lead gripping mechanism and lead case return rapidly.
This phenomenon confirms that when the lead is gripped by the chuck, there is a large gap between the stopper contact part and the front end of the lead, resulting in a problem that the lead protrusion length is not constant. It was done. For this reason, the present invention further aims to solve the problem caused by this phenomenon.

In order to achieve the above object, the core feeding device of the present invention has the following configuration.
In conjunction with the knocking operation slider in the mouth portion a predetermined distance forward, preventing the insertion of the core in contact with the tip of the wick abuts in the following predetermined pressing force while allowing insertion of the core into the inner hole portion of the vicinity of the front end of the slider The resiliently displaceable stopper is fixed, and the core gripping mechanism grips the core and maintains the fixed state until the front end of the core is separated from the contact portion of the stopper, and the knocking operation is performed from this state. further advances, lead gripping mechanism together with the chuck is advanced in conjunction with the lead case which is furnished in the barrel together with the knocking operation releases the gripping of the core, against the abutment portion of the core is the stopper by its own weight fall of the core contact, when releasing the knocking operation from this state, after the lead case and the chuck is lead gripping mechanism retracts to grip the lead fixing slider initial position by biasing force of the spring in the snout portion Core retreats until inserted through the abutment of the stopper, the core from the front end of the slider is characterized in that it is configured to be protruded at a predetermined length.

  Further, the stopper described above is provided in an inner hole portion near the front end of the slider to form a contact portion with which the front end of the core contacts, and a front end hole portion of the slider is provided in front of the contact portion. When the front end of the lead comes into contact with the contact portion and a predetermined pressing force is applied, the contact portion is elastically deformed so that the lead passes through the contact portion and can be inserted into the front end hole portion. The inner hole portion behind the stopper contact portion and the front end hole portion of the slider are provided slightly larger than the core diameter.

The phenomenon to be solved as described above has a small effect when the core is thick and its own weight is large, and has a large effect when the core is thin and its own weight is small. In addition, this phenomenon can be eliminated by providing ventilation means so that the outside air is appropriately ventilated in the core case at a place other than the core insertion front opening hole. The following information is obtained.
Ventilation holes are respectively formed on the side surface of the shaft cylinder serving as the exterior of the core feeding device and the side surface of the core case housed in the shaft cylinder.
The rear end hole of the core case is closed so that the built-in core does not leak, and an air passage is formed through the rear end hole of the core case to allow outside air to vent.

The lead feeding device according to the present invention made to achieve the above object is a lead feeding device in which the lead gripping mechanism releases the lead by a knock operation and the lead gripping mechanism grips the lead when the knocking operation is canceled. A slider is provided that protrudes forward and backward from the tip hole of the tip provided at the tip of the cylinder. The lead can be inserted into the inner hole of the slider, and the tip of the lead contacts below a predetermined pressing force. An elastically displaceable stopper that prevents insertion of the lead is fixed, and the slider is urged rearward by a spring so as to interlock with the lead case via a ring joint, and a lead gripping mechanism is placed behind the slider. When the knocking operation is started, the lead gripping mechanism maintains the lead gripping state, and the slider advances in conjunction with the lead case via the ring joint. With the rider moving forward and blocked from moving forward, the front end of the lead is appropriately separated from the contact part of the stopper, and when the knock operation proceeds further, only the lead case moves forward and the lead gripping mechanism pushes the lead. When the knocking operation is canceled, the lead gripping mechanism holds the lead while the lead gripping mechanism holds the lead, and then the slider retracts to the initial position. Then, the lead passes through the contact portion of the stopper, and the lead protrudes from the front end of the slider with a predetermined length.
Even in the lead feeding device configured as described above, basically, the lead can protrude with a predetermined length, and the protruding length can be stabilized.

In addition, when the knock is released from the state where the lead is in contact with the contact portion of the stopper due to falling of its own weight and the knock operation unit is moved backward, the lead is moved when the chuck is moved backward from the lead holding state to the lead holding state. There is a phenomenon in which the lead is dragged backward by frictional engagement between the chuck and the gripping portion of the chuck, but as described above, there is a phenomenon in which the lead is drawn backward by the phenomenon.
Due to this latter phenomenon, when the lead is gripped by the chuck, a large gap is generated between the contact portion of the stopper and the front end of the lead, and as a result, there is a problem that the protruding length of the lead is not constant, The problem can be solved by providing ventilation means so that the outside air is properly ventilated in the core case.

Embodiments of the present invention will be described with reference to the drawings. 1 to 5 show a lead feeding device according to a first embodiment of the present invention.
As shown in FIG. 1, the lead feeding device according to the first embodiment is made up of components or component units such as the shaft tube 1, the tip portion 2, the slider 3, the lead gripping mechanism 6, the lead case 14, the knock cover 18, and the like. It is configured.

As shown in the figure, the fixed cylinder 10 has a flange portion 10a that protrudes in a substantially rectangular shape in the outer diameter direction, and rib-shaped guide portions (not shown) on both cylindrical sides behind the flange portion 10a. ), And a small-diameter front tube portion 10b is formed at the front end of the flange portion 10a. A fastening ring 8 as a fastening portion is fixed to the inner hole of the tip tube portion 10b by means such as locking or press fitting.
The fastening ring 8 is formed of a thin-walled metal cylinder for the convenience of design such as making the entire writing instrument thinner. However, the fastening ring 8 is not necessarily required as a configuration of the present invention, and is used as an inner hole fastening part of the leading cylinder part 10b. It can also be formed integrally.
The chuck 7 is the same as the chuck used for a normal mechanical pencil, and a split or split slit is formed on the outer periphery of the gripping portion 7a so that it can be expanded and contracted.
The lead gripping mechanism 6 is formed as follows.
The chuck 7 is inserted into the fastening ring 8 fixed to the fixed cylinder 10, the outer periphery of the gripping portion 7 a is engaged with the inner periphery of the fastening ring, and the chuck spring 11 is placed from the rear of the fixed cylinder 10 to the outer periphery of the rear shaft of the chuck 7. In the state where the front end of the chuck spring 11 is brought into contact with the inner step portion formed in front of the fixed cylinder 10 and the rear end of the chuck spring 11 is brought into contact with the front end of the shaft portion 12a of the chuck joint 12, The rear end portion of the chuck 7 is fixed to a locking hole provided in the shaft portion 12 a of the chuck joint 12 by means such as locking or press-fitting so that the chuck joint 12 moves back and forth with respect to the fixed cylinder 10. ing.

Next, the slider 3 will be described.
As shown in the figure, the slider 3 includes a rear member 5, a tip member 4, a guide pipe 4b, and a stopper 4a.
The slider 3 is provided with a stopper 4 a made of an elastic body at a substantially front end of the inner hole of the small diameter tip member 4. And the front part of the guide pipe 4b is being fixed to the inner hole of the tip member 4 so that the rear end of this stopper 4a may be pressed down.
On the other hand, the rear member 5 is formed with a small-diameter shaft portion 5b at the front end and a large-diameter cylindrical portion behind the stepped portion 5c, and on the side surface of the cylindrical portion, there are 2 window portions opened at the rear end. The part provided in more than the place and surrounded by the window part is formed as the leg part 5a.
The slider 3 is formed by inserting and fixing the outer periphery of the rear shaft portion of the front member 4 in the hole portion formed in the shaft portion 5b of the rear member 5.
The slider 3 is inserted through the inner hole of the guide pipe 4b and the inner hole of the stopper 4a, but the tip of the core is in contact with the abutting portion 4c of the stopper 4a below the predetermined pressing force, and the core is not inserted. It is configured as follows. The stopper 4a is basically formed of a material such as elastically displaceable rubber or soft synthetic resin.

Next, the overall configuration of the present invention will be described.
A screw portion is formed on the outer periphery of the front end portion of the shaft cylinder 1, and a rib-shaped guide portion (not shown) is formed on the inner periphery of the front end portion. Further, a hole 1a is formed at a required position behind the screw portion.
First, the above-described core gripping mechanism 6 is inserted from the front side of the shaft tube 1 with the rear end of the flange portion 10a of the fixed tube 10 in contact with the front end of the shaft tube 1, and a rib-shaped guide behind the flange portion 10a. The portion engages with the rib-shaped guide portion of the shaft tube 1, and the fixed tube 10 is prevented from rotating with respect to the shaft tube 1.
Subsequently, the slider 3 described above is inserted from the front of the shaft cylinder 1. At this time, it inserts in the state which the rectangular-shaped both sides | surface of the collar part 10a of the fixed cylinder 10 inserted in the window part of the rear member 5. As shown in FIG.
Further, the spring 9 is mounted in a state where the rear end is brought into contact with the stepped portion 5c of the rear member 5, and the tip portion 2 is fixed by screwing into the screw portion at the front end of the shaft tube 1. At that time, the front portion of the tip member 4 protrudes from the front end hole of the tip portion 2 with an appropriate length, and the front end of the spring 9 abuts on a step portion provided in front of the inner hole of the tip portion 2, thereby fixing the fixed cylinder 10. The flange portion 10a is constricted between the front end of the shaft tube 1 and a step portion provided behind the mouth end portion, and the fixed state of the fixed tube 10 with respect to the shaft tube 1 is completed.
In this state, the slider 3 is urged rearward by the spring 9 and is movable forward against the urging force of the spring 9.

Further, the core case 14 is a long cylindrical body as shown in the figure, and has a bowl-shaped step portion 14a on the front outer periphery, and a hole 14c is drilled at a required position in front of the step portion, and further required on the front side. An elastic piece is formed by providing a slit at a location, and a locking portion 14b having a tapered front surface and a stepped portion on the rear surface is formed on the outer periphery of the front end of the elastic piece.
A return spring 15 is attached to the front outer periphery of the core case with the rear end in contact with the front end of the stepped portion 14a. Subsequently, the ring 14 is elastically deformed from the front end of the core case to a reduced diameter. A joint 13 is mounted, and the return spring 15 is laid in a state where the front end of the ring joint 13 is engaged with the stepped portion of the locking portion 14b and is compressed as appropriate.
The core case 14 is inserted from the rear of the shaft tube 1, the front outer periphery of the ring joint 13 is fitted into the rear end inner periphery of the rear member 5, and the front end of the rear outer periphery formed slightly larger is the rear end of the rear member 5. Then, the locking portion 14b of the core case 14 is fitted into the window portion of the rear member 5.
Further, the core case 1 is rotated such that the core case 14 is movable back and forth with respect to the shaft cylinder 1 by means such as providing a rib or a groove between the outer periphery of the rear end and the inner periphery of the shaft cylinder 1. Further, a means is provided such that the rear end of the lead case 14 comes into contact with the front end of a rotating cylinder 17 to be described later and the lead case 14 does not separate backward.

A screw portion is formed in the inner periphery of the rear end hole of the shaft cylinder 1, and the rotating cylinder 17 is screwed there (not shown), and the front end of the rotating cylinder 17 is abutted against the rear end of the core case 14 described above. Touched. The rotary cylinder 17 has a knob portion 17 a protruding from the rear end of the shaft cylinder 1, and moves back and forth with respect to the shaft cylinder 1 by rotating the knob portion 17 a. An O-ring (such as an elastic body made of rubber or soft synthetic resin) is fastened to the upper part of the screw part to be screwed, so that it does not rotate inadvertently by appropriate frictional resistance with respect to the inner periphery of the hole of the shaft cylinder. Is considered.
From the state in which the front end of the rotating cylinder 17 is in contact with the rear end of the core case 14, the cylindrical eraser receiving body 16 is inserted from the rear end of the rotating cylinder 17, and the front shaft portion 16 b is the core case 14. The rear end holes are fixed in a state where the rotation between them is stopped.
By the way, a rib is formed on the peripheral surface of the inner hole of the rotating cylinder 17 (not shown), and a rib 16a is formed on the shaft side surface of the eraser receiving body 16 so that the rotating cylinder 17 can be rotated almost once. When this is done, the rotation is restricted so that the mutual ribs come into contact with each other to prevent the rotation. The lead case 14 moves back and forth in conjunction with the rotating cylinder 17 that moves back and forth by this one turn. The means for restricting the rotation of the rotating cylinder can be provided without being limited to the above-described embodiment, and the rotation range is not limited to one rotation. Basically, the adjusting mechanism for moving the lead case 14 back and forth within an appropriate range can be provided by various means.
Further, an eraser 19 is detachably secured to the hole of the shaft portion 16c at the rear end of the eraser receptacle 16, and a knock cover 18 is detachably secured to the outer periphery of the shaft portion 16c.

Next, based on FIGS. 1-5, operation | movement of the core supply apparatus of 1st Embodiment is demonstrated.
FIG. 6 shows an enlarged structure of the tip member.
First, FIG. 1 and FIG. 2 show an initial state of operation in which the front end of the core 21 slightly protrudes from the front end of the tip member 4 of the slider.
From this state, the knock cover 18 is knocked to advance the lead case 14, compress the spring 9, and advance the slider 3. (The urging force of the return spring 15 provided between the step 14a of the core case and the rear end of the ring joint 13 is set sufficiently strong against the urging force of the spring 9.)
As shown in FIG. 3, the stepped portion 5 c provided on the rear member 5 of the slider abuts on the inner stepped portion 2 a of the tip portion 2 by advancement. Until this state, the return spring 15 maintains the laid state.
Further, since the lead gripping mechanism 6 remains stationary and holds the lead 21, the front end of the lead 21 is immersed from the front end of the tip member 4 and is located at the contact portion 4 c of the stopper 4 a. .

  As shown in FIG. 4, when the lead case 14 further advances by a knocking operation from the state where the advance of the slider 3 is blocked, the lead case 14 advances while compressing the return spring 15, and the locking portion 14 b of the lead case 14. The front end is in contact with the rear end of the chuck joint 12.

Further, as shown in FIG. 5, when the lead case 14 further advances from the state where the front end of the locking portion 14b of the lead case 14 is in contact with the rear end of the chuck joint 12, the chuck spring 11 is compressed and the chuck joint is compressed. 12, the chuck 7 moves forward, the outer periphery of the gripping portion 7a is released from the tightening of the tightening ring 8, and the gripping of the core 21 is released.
Then, when the gripping of the lead 21 is released, the lead 21 falls by its own weight, and the front end of the lead 21 comes into contact with the contact part 4c of the stopper 4a. The predetermined pressing force applied to the contact portion 4c is a minimum contact force due to the weight of the core to the contact portion 4c.
When the knocking operation is released from this state and the lead case 14 is moved backward, the lead case 14 and the chuck joint 12 are moved backward while the slider 3 is held at the most advanced position, and the lead 21 is gripped again. Also, the compressed state of the return spring 15 is released from this state, and the initial laying state is restored, and the slider 3 can be retracted from that point. At the same time, the return force of the spring 9 causes the slider 3 to move backward together with the lead case 14 to return to the initial state.
As understood from the above operation, the length (projection amount) of the core 21 protruding from the front end of the front member 4 is basically such that the step portion 5c of the rear member 5 abuts on the inner step portion 2a of the tip portion 2. This is the length obtained by subtracting the distance (hereinafter referred to as B dimension) between the front end of the tip member 4 and the contact portion 4c of the stopper 4a from the distance (hereinafter referred to as A dimension).

As described above, in the lead feeding device of the present invention, the lead is protruded from the tip of the writing instrument with a certain length by the knocking operation, and the lead is maintained at a constant length even when the knocking operation is repeated. There is no problem of unintentionally knocking and feeding out the lead during writing, the tip is easily visible and easy to use, and even with a thin lead, there is a concern that the lead may be damaged or damaged by the gripping part of the chuck. Absent.
However, the A dimension and the B dimension vary depending on the accuracy error of the parts and the like. Therefore, the protrusion amount of the lead varies depending on the individual lead feeding devices.
There are several ways to make the protrusion amount of the lead constant, but it seems that it is easiest to adjust the A dimension. As a specific means, the lead case 14 can be moved back and forth by rotating the knob 17a of the rotary cylinder 17 as described above, and the dimension A can be adjusted in conjunction with the lead case 14 so that the protrusion amount of the lead can be adjusted. Can be made constant.
Also, the amount of protrusion of the lead varies depending on the type of the lead (core diameter, hardness, color, etc.) and the preference of the person using the lead feeding device. There are cases where it is desirable to be fixed in a certain state, and each can be provided according to needs.

In addition, as described above, the chuck grips the lead when the knock operation part moves backward from the state where the knock operation part is moved forward most and the lead comes into contact with the rear end of the stopper due to its own weight drop. When retreating from the open state to the lead gripping state, there is a phenomenon that the lead is dragged back by frictional engagement between the lead and the gripping part of the chuck, and a minute gap is generated between the rear end of the stopper and the front end of the lead. . Since this phenomenon is in a substantially constant gap state with respect to repeated knocking operations, there is no problem in making the lead protrusion amount constant by taking into account the error. That is, strictly speaking, the protruding amount of the core is a length obtained by subtracting the B dimension and the error from the A dimension.
Furthermore, as described above, there is a phenomenon that the lead is pulled back to the retreat side separately from the phenomenon. Due to this phenomenon, when the lead was gripped by the chuck, a large gap was formed between the rear end of the stopper and the front end of the lead, and as a result, the problem that the protruding length of the lead was not constant was confirmed. Therefore, in order to solve the problem due to this phenomenon, the present invention provides a hole 1a on the side surface of the shaft tube 1 and further opens a hole 14c on the side surface of the core case 14 so that the outside air is introduced into the core case. By appropriately ventilating, variation due to this phenomenon can be eliminated.
In addition, a groove 13a is provided at a required position on the rear outer periphery of the ring joint 13, which is provided in order to ensure a sufficient air flow path from the hole 1a of the shaft tube 1 to the hole 14c of the core case 14. It is.

7 to 12 show a lead feeding device according to a second embodiment of the present invention.
As shown in FIG. 7 , the lead feeding device according to the second embodiment is made up of components or component units such as the shaft tube 30, the tip 2, the slider 3, the lead gripping mechanism 6, the lead case 32, and the knock cover 34. It is configured.
The lead feeding device according to the second embodiment has substantially the same configuration as the lead feeding device according to the first embodiment, and only differences will be described below.
With respect to the pull-in phenomenon of the core, which is presumed to be due to the fluctuation of the air pressure in the core case when the core gripping mechanism 6 and the core case 32 return rapidly, the present embodiment provides a shaft 33a at the rear end of the eraser receiver 33. A groove-shaped air passage 33b is formed in the inner hole portion of the inner cover portion, and a hole 34a is formed in a side surface of the knock cover 34 fixed to the shaft portion 33a so that the outside air is appropriately vented into the core case. This eliminates the problem of large gaps between the rear end of the stopper and the front end of the lead when the lead is gripped by the chuck, and as a result, the amount of protrusion of the lead can be made constant. Become.

13 to 20 show a lead feeding device according to a third embodiment of the present invention.
As shown in FIG. 13, the lead feeding device according to the third embodiment includes a shaft tube formed by screwing a front shaft 40 and a rear shaft 41, a tip portion 2, a slider 3, a core gripping mechanism 6, and a core case. 42, the knock cover 18 and the like.
The lead feeding device according to the third embodiment has almost the same configuration as the lead feeding device according to the first embodiment, and only the differences will be described below.
A shaft cylinder is provided by connecting the front shaft 40 and the rear shaft 41 by screwing, and a vent hole 43 is formed in the connecting portion for venting the outside air and the inside of the shaft cylinder. A slit at the front end of the core case 42 is formed from the vent hole 43. By appropriately venting the outside air into the lead case through the portion 42a, the problem of causing a large gap between the rear end of the stopper and the front end of the lead when the lead due to this phenomenon is gripped by the chuck is solved. As a result, the protruding amount of the lead can be made constant.
In addition, the means for ventilating the inside of the core case with the outside air is not limited to the above-described embodiment.

The outline of the above-described embodiment of the core feeding device will be briefly described.
The lead gripping mechanism holds the lead and maintains a fixed state until the knock operation unit advances a predetermined distance, and the slider advances in conjunction with the knock operation unit so that the front end of the lead moves away from the contact portion of the stopper. When the knock operation unit is further advanced from the predetermined distance, the chuck advances in conjunction with the knock case together with the knock case, and the core gripping mechanism releases the core gripping. When the knock operation part is retracted by contacting the contact part and releasing the knock operation part, after the chuck is retracted and the lead gripping mechanism grips the lead, the slider moves back to the initial position together with the lead case and the lead is A lead feeding device configured to be inserted through the abutting portion so that the lead can protrude from the front end of the slider with a certain length, and is provided at a place other than the lead insertion front opening hole. Scan the core feeding device outside air comprising ventilation means provided so as to vent appropriate. It becomes.
However, it is also possible to provide the knock operation unit and the slider so as to be directly linked, and to provide the knock operation unit and the lead case so as to be integrated or interlocked so that the slider and the lead case are indirectly linked. it can.
In the above-described embodiment, the knock operation unit is integrated with the rear end of the core case. However, the knock operation unit can be provided as a knock button on the side surface of the shaft tube. Further, although the knocking operation is performed with the finger, the knocking operation can be made possible by using a hammering action such as a weight or an operating force such as electric power.

It is a longitudinal cross-sectional view which shows the whole core feeding apparatus in the initial state of the core feeding apparatus which is the 1st Embodiment of this invention. It is sectional drawing which shows the front part of the core supply apparatus in the initial state of the core supply apparatus which is 1st Embodiment. It is sectional drawing which shows the center feeding apparatus front part in the knock advance first stage of the center feeding apparatus which is 1st Embodiment. FIG. 3 is a cross-sectional view showing a front portion of the lead-out device in the middle stage of knock advancement of the lead-out device according to the first embodiment. It is sectional drawing which shows the center feeding apparatus front part in the knock advance final stage of the center feeding apparatus which is 1st Embodiment. It is sectional drawing which expanded and showed the internal structure of the front member of the slider front end. It is a longitudinal cross-sectional view which shows the whole core feeding apparatus in the initial state of the core feeding apparatus which is the 2nd Embodiment of this invention. It is sectional drawing which shows the core feeding apparatus front part in the initial state of the core feeding apparatus which is 2nd Embodiment. It is sectional drawing which shows the center feeding apparatus front part in the knock advance first stage of the center feeding apparatus which is 2nd Embodiment. It is sectional drawing which shows the center feeding apparatus front part in the middle stage of knock advancement of the center feeding apparatus which is 2nd Embodiment. It is sectional drawing which shows the center feeding apparatus front part in the knock advance final stage of the center feeding apparatus which is 2nd Embodiment. It is a section perspective view showing an aeration way part. It is a longitudinal cross-sectional view which shows the whole core feeding apparatus in the initial state of the core feeding apparatus which is the 3rd Embodiment of this invention. It is sectional drawing which shows the core feeding apparatus front part in the initial state of the core feeding apparatus which is 3rd Embodiment. It is sectional drawing which shows the center feeding apparatus front part in the knock advance initial stage of the center feeding apparatus which is 3rd Embodiment. FIG. 10 is a cross-sectional view illustrating a front portion of a lead feeding device at a stage during knock advancement of the lead feeding device according to the third embodiment. It is sectional drawing which shows the center feeding apparatus front part in the knock advance final stage of the center feeding apparatus which is 3rd Embodiment. It is a cross-sectional perspective view which shows the connection part of a shaft cylinder. It is a conveyance sectional view of a lead case. It is a perspective view which shows the external appearance of a core case. It is sectional drawing of the common core supply apparatus of the conventional mechanical pencil. It is sectional drawing of the writing lead holder proposed by Japanese Utility Model Laid-Open No. 55-99887. It is sectional drawing which shows the operation state of the writing core holder shown in FIG. It is sectional drawing which shows the operation state of the writing core holder shown in FIG. It is sectional drawing which shows the operation state of the writing core holder shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft cylinder 1a Hole 2 Tip part 2a Inner stage part 3 Slider 4 Tip member 4a Stopper 4b Guide pipe 4c Contact part 5 Rear member 5a Leg part 5b Shaft part 5c Step part 6 Core gripping mechanism 7 Chuck 7a Holding part 8 Tightening ring DESCRIPTION OF SYMBOLS 9 Spring 10 Fixed cylinder 10a collar part 10b Tip cylinder part 11 Chuck spring 12 Chuck joint 12a Shaft part 13 Ring joint 13a Groove 14 Core case 14a Step part 14b Locking part 14c Hole 15 Return spring 16 Eraser receiving body 16a Rib 16b Shaft part 16c Shaft 17 Rotating cylinder 17a Knob 18 Knock cover 19 Eraser 20 O-ring 21 Core 30 Shaft 31 Ring joint 32 Core case 33 Eraser receiving body 33a Shaft 33b Grooved air passage 34 Knock cover 34a Hole 40 Front shaft 41 Rear shaft 42 Core case 4 a slit portion 43 vents 123 barrel 124 shaft coupling 125 chuck 126 fasteners 127 lead case 128 chuck spring 129 core 130 proboscis portion 130a stepped portion 131 slider 131a shaft portion
132 End pipe 133 Holding chuck 151 Shaft cylinder 151a Through hole 152 Tapered hole 153 Chuck 154 Core case 154a Hole 155 Core 156 Annular projection 157 Coil spring 158 Coil spring 159 Support arm 160 Stopper 161 Cap

Claims (3)

In conjunction with the knocking operation, the slider in the tip moves forward a predetermined distance, allowing the core to be inserted into the inner hole near the front end of the slider and preventing the core from being inserted by contacting the tip of the core below a predetermined pressing force. The resiliently displaceable stopper is fixed, and the core gripping mechanism grips the core and maintains the fixed state until the front end of the core is separated from the contact portion of the stopper, and the knocking operation is performed from this state. When the needle is further advanced, the chuck moves forward in conjunction with the knock case and the lead gripping mechanism releases the lead gripping, and the lead hits the stopper contact part due to the fall of the lead weight. contact, when releasing the knocking operation from this state, after the lead case and the chuck is lead gripping mechanism retracts to grip the lead fixing slider initial position by biasing force of the spring in the snout portion Is a lead feeding device configured such that the lead passes through the abutting portion of the stopper and the lead can protrude from the front end of the slider with a certain length. A core feeding device provided with a vent so as to ventilate. The core feeding device according to claim 1, wherein a vent is formed on a side surface of the shaft cylinder serving as an exterior of the core feeding device. The lead feeding device according to claim 1, wherein the rear end hole of the lead case is closed so that the built-in lead does not leak, and a vent passage is formed through the rear end hole of the lead case to allow outside air to flow.

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