JPH0645789U - Mechanical pencil chuck set - Google Patents

Abstract

(57) [Summary] [Purpose] A mechanical pencil chuck set with a structure in which a fixed core chuck is tightened with a ball. It is possible to provide a chuck set. [Structure] The present chuck set 1 includes a resin-made chuck case 2 having protrusions 6 at appropriate positions on an inner circumference thereof, and a core-fixing chuck 3 having a chuck head 3a that can be expanded and contracted, with a coil spring 5 interposed therebetween. A step portion 7 that is movably fitted and is opposed to the protrusion 6 at a rear side of the protrusion 6 is provided at a rear portion of the lead fixing chuck 3 so that the lead fixing chuck 3 advances and the protrusion 6
When the stepped portion 7 comes into contact with the ball 4, the ball 4 is prevented from coming off, and when the rear end portion 9 is pressed with a force of a predetermined value or more and the lead fixing chuck 3 advances, the stepped portion 7 gets over the projection 6 by elastic deformation. The rear end 9 is held by the front end of the protrusion 6, and at that time, the groove 3b of the chuck head 3a is appropriately exposed from the tip of the tightening barrel 2 ', and the ball 4 can be easily inserted into the groove 3b. .

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention has a structure in which a lead-fixing chuck is tightened with a ball to provide a sufficient lead holding force for writing, but a mechanical pencil chuck set that requires only a small force to pull out the lead from the chuck. Regarding improvement.

[0002]

[Prior art]

 As a conventional example, the present applicant has disclosed a finger-feeding type sharp pencil in Japanese Utility Model Publication No. 64-1107. According to this, the joining cylinder 6 is press-fitted and fixed to the shaft cylinder 7 on the outer periphery of the front end portion of the chuck case 2, and the shaft joint 8 is screwed to the inner diameter portion of the front end of the joining cylinder 6. A screw portion is formed on the outer diameter portion of the front end of the shaft coupling 8, and a cap 10 having a tip pipe 9 fixed thereto is screwed onto the screw portion. A central portion 14 of a feeding body 13 fitted around a holding chuck 12 is provided inside the shaft coupling 8, and the feeding body 13 projects a piece 15 outward from the central portion and has a tip portion at its tip. A short tubular touch finger 16 is configured. The piece portion 15 of the feeding body 13 penetrates a slit 17 provided in the axial direction from the front end of the shaft coupling 8 toward the rear, and exposes the touching portion 16 on the outer peripheral portion of the shaft coupling 8. . When the lead is normally fed apart from the touching-out, the lead case 1 connected to the knock operation part compresses the coil spring 20 interposed between the lead tube 1 and the joining cylinder 6, and the chuck case 2 is connected to the shaft joint. 8 is advanced until it abuts against the rear end of the lead 8, then the lead fixing chuck 4 is opened and the lead is fed out. When the knock is released, the chuck case 2 retreats, but at that time, it is necessary to retreat while the lead fixing chuck 4 remains open. Therefore, the lead guide 1 needs to be configured to frictionally engage the outer circumference of the chuck case 2 with a force stronger than that of the coil spring 5. Further, in this chuck set, the core fixing chuck 4 is always biased rearward by the coil spring 5 with respect to the chuck case 2, so that the balls 3, 3'are inserted into the concave grooves of the core fixing chuck 4. At this time, the rear end of the lead-fixing chuck 4 must be pressed to hold the concave groove appropriately exposed from the front end of the chuck case 2, which makes the assembly troublesome. Also, a ring for preventing the balls from coming off is fixed to the tip of the chuck case 2 so that the balls do not come off during normal operation, which is wasteful in terms of cost.

[0003]

[Problems to be solved by the device]

 Therefore, the present invention eliminates the waste of the conventional chuck set, and facilitates the laborious assembly of ball insertion to provide an inexpensive chuck set.

[0004]

[Means for Solving the Problems]

 In order to achieve the above object, the mechanical pencil chuck set of the present invention has a sufficient core holding force for writing due to the structure in which the core fixing chuck is tightened with a ball, but is not suitable for pulling out the core from the chuck. In mechanical pencils that require only a small amount of force, a lead-fixing chuck is attached via a coil spring to a resin chuck case that has protrusions at appropriate positions on the inner circumference of the rear hole so that it can move back and forth. A step portion is provided at the rear of the fixed chuck so as to face the protrusion behind the protrusion at a predetermined distance, and when the core fixing chuck advances and the step portion comes into contact with the protrusion, the ball is prevented from coming off, and a force higher than a predetermined value is applied. When the rear end of the lead-fixing chuck is pressed by and the lead-fixing chuck moves forward, elastic deformation causes the step to climb over the protrusion and the rear end to be held at the front end of the protrusion. Groove is exposed appropriately from the tip of the clamping cylinder in the chuck case, the insertion of the ball easily into the groove.

[0005]

【Example】

 First, FIG. 1 shows an example in which the chuck set of the mechanical pencil of the present invention is used in a finger-feeding type sharp pencil. A lead guide 13 is integrally formed at the tip of the lead case 12, and a protrusion 14 is provided on the outer periphery of the lead guide 13. Further, a slit portion 15 is formed on the rear end side surface of the chuck case 2, and a locking portion 16 is provided on the side surface portion. The lead guide 13 is fitted into the rear end hole of the chuck case 2, and the protrusion 14 and the locking portion 16 are engaged with each other. The core case 12 is normally urged rearward by the coil spring 20 between the flange portion 17 and the step portion 19 of the shaft cylinder 18.

By the way, FIG. 2 shows a chuck set 1 which is the gist of the present invention. At the tip of the chuck case 2, a tightening tube 2'is fixed. A taper-shaped hole 10 is provided in the inner diameter portion of the front end of the tightening tube 2 ', and a ball-fixing chuck 3 in which a ball 4 contacting the taper surface is fitted into a concave groove 3b formed on the outer surface of the chuck head 3a is provided. The core fixing chuck 3 is pressed rearward by a coil spring 5 interposed between the core fixing chuck 3 and the rear end 11 of the tightening cylinder 2. The core fixing chuck 3 is made of a synthetic resin molded product that has excellent elasticity and is resistant to abrasion, and is constructed by combining two split cylindrical bodies, and a slit 3d is formed rearward from the chuck head 3a. The chuck head 3a is configured to be expandable and contractible. The lead fixing chuck may be made of an integral metal.

When the writing pressure acts on the core, the ball 4 rolls and the core fixing chuck 3 is tightened by the wedge effect to hold the core. However, when the core is pulled forward, the spring force of the coil spring 5 is increased. It is configured to be possible with a small force of a few grams by setting a weak value. By the way, the chuck case 2 is made of a resin molded product, and the tightening cylinder 2'is made of metal. Originally, the chuck case and the closing cylinder are integrally formed, but the cost is high if they are made of metal due to the complicated processing. If it is made of resin, the durability will be insufficient. The reason why the lock cylinder 2'is made of metal is that consideration was given to wear resistance due to ball rolling and rigidity of the tapered portion. If the durability is compromised, an integral resin molded product may be used.

Returning to the explanation of FIG. 1 again, a screw portion is formed on the inner diameter portion of the front end of the shaft cylinder 18, and a resin mouthpiece 22 having a tip pipe 21 fixed thereto is screwed onto the screw portion. . The base 22 may be press-fitted into the outer diameter portion of the front end of the barrel 18. Further, the tip 22 may be integrally formed with the base 22. Further, a guide slit 23 is formed in the center of the shaft side surface of the mouthpiece 22 slightly forward, and a payout body 24 is slidably fitted inside the mouthpiece 22. A holding chuck 25 is fixedly provided at the center of the feeding body 24, and a locking piece 26 having a locking groove is integrally formed at a predetermined position corresponding to the guide slit 23 on the outer periphery of the rear end side. The stopper 26 is fitted into the guide slit 23 and is slidable. Further, there is provided a space corresponding to the amount of extension by knocking operation, between the tip of the fastening cylinder 2'and the facing surface when the delivery body 24 is at the frontmost position of the mouthpiece 22.

Further, the touch finger portion 27 is made of a resin having a ring shape, and a protrusion is formed at a portion corresponding to the locking groove on the inner peripheral portion of the substantially tip end. The touching finger portion 27 is fitted to the outside of the mouthpiece 22, and the protrusions are elastically fitted into the locking grooves to be engaged with each other, so that the touching finger portion 27 and the feeding body 24 are integrally interlocked. Further, there is provided a space between the rear end of the touching finger portion 27 and the mouthpiece 22 for extending the touching finger.

In addition, inside the touching finger portion 27, a coil spring 28 is interposed between the touching finger portion 27 and the base 22, and the touching finger portion 27 is biased forward in a pressed state. The spring force of this spring may be larger than the force for pulling out the lead from the lead fixing chuck 3, so it can be set to about 10 to 20 grams.

[0011]

[Action]

 The feeding body 24 can be slid rearward by pulling the external touching finger portion 27 lightly backward with a finger and bringing the locking piece 26 along the guide slit 23. Then, when the finger is released, the holding chuck 25 holds the lead and returns to the front, so that the lead can be fed out. This amount of extension is the value of the interval at which the rear end of the touching finger portion 27 abuts the stepped portion of the mouthpiece 22 that faces it. When the lead is normally fed out, the rear end of the knock cover (not shown) connected to the rear of the lead case 12 may be knocked, and the lead guide 13 at the tip of the lead case 12 is provided with the collar portion 17 and the shaft cylinder 18. While compressing the coil spring 20 interposed between the stepped portion 19 and the stepped portion 19, the tightening tube 2'integrated with the chuck case 2 is advanced and the tip thereof is abutted against the stepped portion 29 of the feeding member 24 facing each other. In this state, since the chuck case 2 is prevented from advancing, the protrusion 14 elastically rides over the locking portion 16 and moves forward, so that the tip of the lead guide 13 comes into contact with the rear end of the lead fixing chuck 3 to move the lead. The fixed chuck 3 is opened and the lead is fed out. Next, when the knock of the knock cover is released, the rear end of the protrusion 14 comes into contact with the front end of the locking portion 16, so that the lead fixing chuck 3 is left open and the chuck case 2 is retracted together with the lead case 12. When the case 2 is prevented from retreating at the inner stage (not shown) of the shaft cylinder 1, only the lead case 12, that is, the lead guide 13 is retracted, and the protrusion 14 again passes over the locking portion 16 and returns to the original state. It

By the way, when the chuck set 1 is used in a mechanical pencil, the step 7 is set so as not to contact the projection 6 even at the most advanced position of the lead fixing chuck 3. However, since the chuck set 1 is handled as a single unit in the assembly work and transfer, the core fixing chuck 3 may inadvertently advance due to the weak coil spring 5. Even in such a case, in the case of the present invention, the step 7 contacts the projection 6 as shown in FIG. Further, as shown in FIG. 4, when the rear end 9 is locked to the front end of the protrusion 6, the concave groove 3b of the chuck head 3a is appropriately exposed and held from the front end of the tightening cylinder 2 '. The ball 4 can be easily inserted through the guide. Also, by pushing back the tip of the chuck head 3a, the state shown in FIG. 2 can be set. In particular, it is convenient when using an automatic machine.

[0013]

[Effect of device]

 As described above, the present invention eliminates the need for a ring for preventing the balls from coming off unlike the conventional chuck set, facilitates the insertion of balls that are troublesome, and makes it cheaper by using an automatic machine or the like. It is possible to provide a chuck set.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a finger-feeding type mechanical pencil using a chuck set of the present invention.

FIG. 2 is a vertical sectional view showing a chuck set of a mechanical pencil which is an embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view of the chuck set showing a state in which the lead fixing chuck is moved forward and the rear step is in contact with the protrusion of the chuck case.

FIG. 4 is a vertical cross-sectional view of the chuck set showing a state in which the rear end of the lead-fixing chuck is locked to the protrusion of the chuck case and the concave groove of the chuck head is appropriately exposed from the tip of the tightening cylinder. is there.

[Explanation of symbols]

 1 Chuck Set 2 Chuck Case 2'Tightening Tube 3 Core Fixed Chuck 3a Chuck Head 3b Recessed Groove 3c Core Grip 3d Slot 4 Ball 5 Coil Spring 6 Projection 7 Step 8 Step 9 Rear End 10 Tapered Hole 11 Rear End 12 Core Case 13 Core Guide 14 Projection 15 Slit 16 Locking Part 17 Collar 18 Shaft Cylinder 19 Step 20 Coil Spring 21 Tip Pipe 22 Mouth 23 Guide Slit 24 Feeding Body 25 Holding Chuck 26 Locking Piece 27 Touch Finger 28 Coil Spring 29 Step

Claims (1)

[Scope of utility model registration request] 1. A structure in which a lead fixing chuck is tightened with a ball has a sufficient lead holding force for writing.
In a mechanical pencil that requires only a small force to pull out the lead from the chuck, it has a lock tube 2'having a tapered hole 10 at its tip, and a projection 6 at an appropriate position on the inner circumference of the rear hole. A core fixed chuck 3 having a chuck head 3a, which has a slit 3d formed from the tip and is expandable and contractible, is attached to a resin-made chuck case 2 having the above-mentioned structure so as to be movable back and forth through a coil spring 5. The ball 4 is loosely fitted in the groove 3b formed on the side surface of the head 3a, the ball 4 is tightened by the tapered hole 10 of the tightening cylinder 2 ', and the core is the core gripping part of the inner hole of the chuck head 3a. 3c, and a step portion 7 is provided at the rear of the lead fixing chuck 3 to face the above-mentioned protrusion 6 with a predetermined distance behind and to allow the lead fixing chuck 3 to move forward and to reach the protrusion 6. Ball 4 when part 7 abuts Withdrawal is prevented, when the rear end portion 9 with a predetermined force or more is pressed lead fixing chuck 3 moves forward,
Due to the elastic deformation, the step portion 7 gets over the projection 6 and the rear end portion 9 is held at the front end of the projection 6, and at that time, the concave groove 3b of the chuck head 3a is appropriately exposed from the tip of the tightening cylinder 2 ', Three
A mechanical pencil chuck set characterized in that the ball 4 can be inserted into b.