Abstract:
In a stick-like object receiving member having safety precautions, which receives a stick-lik object, a sufficient air passage is secured without exerting an influence on the size of the stick-like object or the receiving member. An eraser receiving member  16,  which is the stick-like object receiving member, includes a cylindrical side portion  16   b  which engages with at least a part of the outer peripheral surface of an eraser  13,  and surrounds at least a part of the outer peripheral surface of the eraser  13,  and a bottom portion  16   a  which closes one end of the cylindrical side portion  16   b . A slit  16   e  is formed in the cylindrical side portion  16   b  and bottom portion  16   a  so as to penetrate the cylindrical side portion  16   b  and bottom portion  16   a  in the axial direction, and the slit  16   e  serves as an air passage.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a stick-like object receiving member used for a writing instrument etc. and, more particularly, to a stick-like object receiving member having safety precautions and a barrel provided with the stick-like object receiving member.  
           [0003]    2. Description of the Related Art  
           [0004]    As an example of a conventional stick-like object receiving member of this type, there is an eraser receiving member that is mounted in the end portion of a writing instrument to receive an eraser. This eraser receiving member can be removed from the body of the writing instrument as it is mounted detachably to the end portion of the writing instrument, and it is considerably smaller than the writing instrument as a whole in this state. Considering a case where the eraser receiving member or the writing instrument is swallowed inadvertently in a state in which the eraser receiving member is removed from the body of writing instrument or in a state in which the eraser receiving member is mounted, it is necessary to provid safety precautions to the eras r rec iving memb r to secure the airway.  
           [0005]    As an eraser receiving member provided with such safety precautions, for example, a safety cap described in National Publication of International Patent Application No. 2001-504764 is known. The safety cap described in this Publication has a cylindrical hollow body, an eraser formed of a substantially solid material, which is accommodated in one end of the hollow body and has a portion extending beyond the end of the body, and an air passage disposed between the outer peripheral surface of the eraser and the inner peripheral surface of the body to secure the airway from one end of the body via the body. This air passage is created as a space formed between the inner peripheral surface of the body and the outer peripheral surface of the eraser by a plurality of protrusions formed on the inner peripheral surface of the body or by a plurality of protrusions formed on the outer peripheral surface of the eraser.  
           [0006]    However, the safety cap described in this Publication utilizes the small protrusions formed on the inner peripheral surface of the body or on the outer peripheral surface of the eraser to form the air passage, and thus presents a problem in that only a very narrow gap is formed between the inner peripheral surface of the body and the outer peripheral surface of the eraser, which is not satisfactory for the air passage. In order to form a large air passage, the heights of protrusions must be increased. In this case, however, the outside diameter of eraser becomes small, so that the eraser itself must be made small. Maintaining the size of eraser makes it necessary to increase the inside diameter of body. This results in the increased size of body, and may adversely affect the design of writing instrument.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention has been made to solve the above problem, and accordingly an object thereof is to provide a stick-like object receiving member having safety precautions capable of securing a sufficient air passage without exerting an influence on the size of a stick-like object or a receiving member, and a barrel provided with the stick-like object receiving member.  
           [0008]    To achieve the above object, a stick-like object receiving member with safety precautions for receiving a stick-like object according to the present invention, includes a cylindrical side portion which engages with at least a part of the outer peripheral surface of the stick-like object and surrounds at least a part of the outer peripheral surface of the stick-like object, and a bottom portion which closes one end of the cylindrical side portion. A slit is formed in the cylindrical side portion and bottom portion so as to pen trate the cylindrical side portion and bottom portion in the axial direction, and the slit serves as an air passage.  
           [0009]    In a state in which the stick-like object engages with the cylindrical side portion, a portion in which the slit penetrating the cylindrical side portion and bottom portion in the axial direction is depressed to the inside diameter side as compared with the cylindrical side portion, and thus the slit serves as an air passage. Therefore, even if the stick-like object receiving member is swallowed, the airway can be secured by the air passage formed by the slit. The slit, which forms an air passage, is formed in the cylindrical side portion and the bottom portion. Since this configuration is different from a conventional configuration in which an air passage is formed between the inner peripheral surface of the cylindrical side portion and the outer peripheral surface of the stick-like object, the air passage can be formed and also the size of air passage can be adjusted without exerting an influence on the inside diameter of cylindrical side portion or the outside diameter of stick-like object.  
           [0010]    A plurality of the slits can be formed at intervals in the circumferential direction. Thereby, a large cross-sectional area of air passage can be secured.  
           [0011]    The cylindrical side portion can hav a collar portion protruding outward in the radial direction on the other end thereof.  
           [0012]    Also, the present invention provides a barrel having the above-described stick-like object receiving member and a cylindrical casing in which the stick-like object receiving member is mounted detachably at one end thereof.  
           [0013]    Further, a barrel, according to the present invention, having the stick-like object receiving member is provided with the cylindrical side portion having the collar portion and a cylindrical casing in which the stick-like object receiving member is mounted detachably at one end thereof. The barrel includes an end face to which the collar portion of the stick-like object receiving member is locked, an inner peripheral surface which engages with at least a part of the cylindrical side portion of the stick-like object receiving member other than the collar portion and surrounds the outer peripheral surface of the cylindrical side portion other than the collar portion, and a step portion formed on the inner peripheral surface so as to be separated from the bottom portion of the stick-like object receiving member. A gap formed between the step portion and the bottom portion communicates with the slit and forms an air passage together with the slit.  
           [0014]    The present disclosur relates to subject matter contained in Japanese Patent Application No. 2002-244279, filed on Aug. 23, 2002, which is expressly incorporat d herein by reference in its entirety. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a longitudinal sectional view of a writing instrument provided with a stick-like object receiving member in accordance with the present invention;  
         [0016]    [0016]FIG. 2A is a perspective view of a stick-like object and a stick-like object receiving member, and FIG. 2B is a perspective view showing a state in which the stick-like object is inserted in the stick-like object receiving member;  
         [0017]    [0017]FIG. 3A is a side view of a stick-like object receiving member, FIG. 3B is a view taken in the direction of arrow  3   b  of FIG. 3A, and FIG. 3C is a sectional view taken along the line  3   c - 3   c  of FIG. 3A;  
         [0018]    [0018]FIG. 4 is a partially sectional view of an essential portion showing a state in which a stick-like object receiving member is mounted in a knock casing; and  
         [0019]    [0019]FIG. 5 is a view taken in the direction of arrow  5  of FIG. 4. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]    An embodiment of the present invention will now be described with reference to the accompanying drawings.  
         [0021]    [0021]FIG. 1 is a longitudinal sectional view of a writing instrument provided with a stick-like object receiving member in accordance with the present invention. In this example, a mechanical pencil is taken as an example of writing instrument. However, the writing instrument is not limited to the mechanical pencil, and the present invention can be applied to any type of writing instrument such as ball-point pen, felt pen, fountain pen, and stylus pen. This mechanical pencil mainly has an external casing  10 , a knock casing  12 , and an intermediate casing  14 , and a lead delivering mechanism  18  for delivering a lead is incorporated in the external casing  10 . As publicly known, the lead delivering mechanism  18  includes a lead tank  20  for storing a lead L, a lead tightening chuck  22  whose rear end is pressed into the lead tank  20  and whose front end portion tightens the lead L, a chuck ring  24  which is disposed on the outer periphery side of the lead tightening chuck  22  to tighten the lead tightening chuck  22 , a sleeve  26  for regulating the rearward movement of the chuck ring  24 , and a chuck spring  28  interposed between the sleeve  26  and the front end of the lead tank  20  to always urge the lead tank  20  and the lead tightening chuck  22  rearward. An elastic blade portion  26   a  formed on the sleeve  26  is locked to an opening  10   a  formed in the external casing  10 , by which the lead delivering mechanism  18  is held in the external casing  10 .  
         [0022]    Th rear end of the lead tank  20  protrudes and ext nds from a rear end opening  10   d  of the external casing  10  so as to be capable of accommodating a lead longer than the total length of the external casing  10 . In an annular space between the inner peripheral surface at the rear of the external casing  10  and the outer peripheral surface at the rear of the lead tank  20 , the tip end of the intermediate casing  14  is inserted, and is fitted in the annular space. The tip end of the intermediate casing  14  is connected to the lead tank  20 . Also, the rear end of the intermediate casing  14  is connected to the knock casing  12 . The connecting force between the intermediate casing  14  and the knock casing  12  is set so as to be weaker than the connecting force between intermediate casing  14  and the lead tank  20  so that the knock casing  12  is detachable from the intermediate casing l 4 . Thus, the knock casing  12  is detachable with respect to the intermediate casing  14  and the external casing  10 .  
         [0023]    The knock casing  12  is integrally formed with a clip  12   b  on the outside surface thereof. Also, at the rear end of the knock casing  12 , an eraser receiving member  16 , which is a stick-like object receiving member, for receiving an eraser  13 , which is a stick-like object, is mounted detachably. The stick-like object is not limited to the eraser  13 , and an arbitrary object such as an error-correcting stick, solid paste, and marker can be received by the stick-like object receiving member  16 . The length in the axial direction of stick-like object need not necessarily be larger than the outside diamet r thereof, but the stick-like object is supposed to b solid so that air cannot flow freely therein.  
         [0024]    As shown in FIGS. 2 and 3, the eraser receiving member  16  has a bottom portion  16   a  for receiving the bottom surface of the eraser  13 , a cylindrical side portion  16   b  which engages with a part of the outer peripheral surface of the eraser  13  and surrounds the part of the outer peripheral surface of the eraser  13 , one end thereof being closed by the bottom portion  16   a , and an opening portion  16   d  which opens at the other end of the cylindrical side portion  16   b  so as to face the bottom portion  16   a . The eraser  13  protrudes from the eraser receiving member  16  through the opening portion  16   d  so that it can be used. The cylindrical side portion  16   b  has a collar portion  16   c , which protrudes in the radial direction to be brought into contact with the rear end of the knock casing  12 , on the side of opening portion  16   d.    
         [0025]    Furthermore, the eraser receiving member  16  is formed with a slit  16   e  which extends so as to penetrate the cylindrical side portion  16   b  and the bottom portion  16   a  in the axial direction to form an air passage. The number of the slits  16   e  can be made one. Also, as in the example shown in the figures, a plurality of (three in this example) slits  16   e  can be formed at intervals in the circumferential direction. The slit  16   e  need not necessarily extend in parallel with the axial dir ction, or n ed not extend straight.  
         [0026]    Also, on the inner peripheral surface of the cylindrical side portion  16   b  of the eraser receiving member  16 , ribs  16   f  for engagement with the eraser  13  are formed at appropriate places, and on the outer peripheral surface of the cylindrical side portion  16   b , ribs  16   g  for engagement with the knock casing  12  are formed at appropriate places. By adjusting the height and number of the ribs  16   f  and  16   g , the engagement forces between the eraser receiving member  16  and the engaging mating elements can be adjusted. The engagement force between the eraser receiving member  16  and the knock casing  12  is set so as to be larger than the engagement force between the eraser receiving member  16  and the eraser  13 . The ribs  16   f  and  16   g  are ribs for engagement, and therefore the protrusion height thereof is relatively small. Therefore, a gap formed between the inner peripheral surface of the cylindrical side portion  16   b  of the eraser receiving member  16  and the outer peripheral surface of the eraser  13  by the rib  16   f  is very small even if it exists, so that the gap cannot serve as an air passage. Similarly, a gap formed between the outer peripheral surface of the cylindrical side portion  16   b  of the eraser receiving member  16  and the inner peripheral surface of the knock casing  12  by the rib  16   g  is very small even if it exists, so that the gap cannot serve as an air passage. When one end of th eraser  13  is inserted in the eraser r ceiving member  16  through the opening portion  16   d , th outer peripheral surface of th one end portion engages with the inner peripheral surface of the cylindrical side portion  16   b . When the eraser  13  has not be used yet, the eraser  13  is inserted to a position at which the bottom surface of the eraser  13  comes into contact with the bottom portion  16   a  of the eraser receiving member  16 .  
         [0027]    As shown in FIG. 4, when the eraser receiving member  16  is mounted in the knock casing  12 , the collar portion  16   c  of the eraser receiving member  16  is locked to the rear end face of the knock casing  12 , and the outer peripheral surface of the cylindrical side portion  16   b  other than the collar portion  16   c  engages with the inner peripheral surface of the rear end portion of the knock casing  12 . At this time, the bottom portion  16   a  of the eraser receiving member  16  does not come into contact with the knock casing  12 , and a gap  17  is formed between the bottom portion  16   a  of the eraser receiving member  16  and a step portion  12   a  formed on the inner peripheral surface of the knock casing  12 .  
         [0028]    In the eraser receiving member  16  constructed as described above, as shown in FIG. 2B, in the state in which the eraser receiving member  16  is removed from the knock casing  12 , the portion of the slit  16   e  penetrates in the axial direction over the entire length of the eraser receiving member  16 , and the portion of the slit  16   e  is depressed to the inside diamet r side as compared with the cylindrical side surface  16   b , so that the slit  16  serves as an air passage. Therefore, even if the eras r receiving member  16  is swallowed and, for example, the collar portion  16   c  is caught by any portion, the airway can be secured by the air passage formed by the slit  16   e.    
         [0029]    Also, as shown in FIG. 4, even in a state in which the eraser receiving member  16  is mounted in the knock casing  12  (a combination of the eraser receiving member  16  and the knock casing  12  in the state in which the eraser receiving member  16  is mounted in the knock casing  12  is referred to as a “barrel”), the portion of the slit  16   e  penetrates the eraser receiving member  16  in the axial direction, and the portion of the slit  16   e  is depressed to the inside diameter side as compared with the cylindrical side surface  16   b  to form a gap between the inner peripheral surface of the knock casing  12  and the eraser receiving member  16 , so that the slit  16   e  serves as an air passage. In FIG. 5, the colored portions indicate air passages formed by the slits.  16   e . Further, the gap  17  formed between the bottom portion  16   a  of the eraser receiving member  16  and the step portion  12   a  of the knock casing  12  serves as an air passage communicating with the air passage formed by the slit  16   e . Therefore, even if the eraser receiving member  16  is swallowed together with the knock casing  12 , the airway can be secured by the slit  16   e  and the gap  17 .  
         [0030]    As described above, according to the present invention, since the slit  16   e  formed so as to penetrate the cylindrical sid portion  16   b  and the bottom portion  16   a  of the eras r receiving member  16  is used as an air passag, the air passag does not at all affect the insid diameter of the raser receiving member  16  or the outside diameter of the eraser  13 . Therefore, the eraser receiving member  16  and the eraser  13  can have a desired size. In addition, by setting the width, number, etc. of the slits  16   e  properly, the cross-sectional area of slits  16   e  colored in FIG. 5 can be adjusted arbitrarily, and thereby a cross-sectional area sufficient as an air passage can be secured.  
         [0031]    While the principles of the invention have been described above in connection with specific embodiments, and particular modifications thereof, it is to be clearly understood that this description is made only by way of example and not as a limitation on the scope of invention.