DUAL REFILL WRITING UTENSIL

Abstract: A writing utensil with dual refills is described, which when a cap (3) on a body (1), is rotated in one direction or the other, first and second refills (4, 5) are alternately projected and retracted from the body (1), whereby either the first or second refill can be held at an operating position whilst the other is withdrawn.

Description: This invention relates to a dual refill-type writing utensil. A conventional dual refill writing utensil is described in US-A-4,227,822. The writing utensil has a column or guide post connected to the top end of a lower outer cylinder or body, while sliders on a mechanical pencil holder and a ball point pen-holder are slidable in axially grooves on the guide post. A cam cylinder is fitted into an upper outer cylinder cap and these are slidable and rotatably secured to the guide post, so that a cam surface of the cam cylinder can engage the sliders on the mechanical pencil holder and ball point pen-holder. The mechanical pencil holder and the ball point pen-holder are alternately projected and retracted from the lower end of the body upon rotation of the cap by means of the incorporated cam cylinder engaging and urging each slider, and associated refill. In this conventional writing utensil, the sliders can easily slip out from the axially grooves because of rotational friction (rotational load), and thus the sliders are not smoothly slid upon rotation of the cam cylinder. As a result, the alternate projection and retraction of the mechanical pencil holder and the ball point pen-holder cannot be smoothly accomplished. The formation of the guide post with a columnar shape, results in a large diameter or cap, so that the whole construction of the writing utensil becomes large. In such a conventional writing utensil, since a separate cam cylinder is required, the number of parts is large, the construction of the writing utensil is complicated and expensive, assembly of the parts is complicated, so that productivity of the utensil is reduced. Furthermore in such a conventional writing utensil, because the cam cylinder and guide post are separately constructed, they have to be precisely concentrically assembled. This increases the cost of manufacture while decreasing productivity. Also, the cam cylinder plays easily with respect to the guide post, when rotated or moved axially, so that the cam cylinder cannot be smoothly operated. For this reason, the mechanical pencil holder and ball point pen-holder cannot alternately be projected and retracted smoothly, so that the functionability of the writing utensil deteriorates. The present invention seeks to provide a writing utensil of simplified construction in order to be able to enhance productivity and diminish cost. The present invention seeks to provide a writing utensil with refills each having a slider which can be slide reliably, axially in the utensil to project or retract the associated refill. The present invention seeks to provide a writing utensil of compact and efficient construction. According to a first aspect of the invention there is provided a writing utensil comprising: a tubular body; a guide post detachably fitted to one end of the tubular body; a cap; means rotatably securing the cap to body; first and second sliders which are axially slidable on the guide post; and first and second refills attached to the first and second sliders respectively; characterised in that cam surface are provided on the sliders, and a cam engaging projection provided on the cap, so that in use, when the cap is rotated, the cam surface of one or other of the sliders can engage with the cam engaging projection, and the corresponding refill be projected or retracted. According to a second aspect of the invention there is provided a writing utensil comprising: a tubular body; a guide post detachably fitted to one end of the tubular body; a cap; means rotatably securing the cap to the body; first and second sliders which are axially slidable on the guide post; and first and second refills attached to the first and second sliders respectively; a cam cylinder in the cap operative by rotation of the cap to engage the sliders to alternately project or retract the refills characterised in that a portion of the guide post on which the sliders slide, is rectangular, and each slider 207) has at least one hook portion for engaging a side surface of that portion of the guide post. According to a third aspect of the invention there is provided A writing utensil comprising: a tubular body; a cap; means rotatably securing the cap to the body; guide means detachably secured to the body; first and second refills axially slidable in the guide means; a cam cylinder in the cap, whereby rotation of the cylinder causes the cam cylinder to engage with the refills to alternately project and retract the refills; characterised in that the means rotatably securing the cap to the body includes a core shaft formed integrally with the cam cylinder, and axially slidable within the guide means so as to allow the cam cylinder to by in the guide means to allow a knocking operation of the cap. According to a further aspect of the invention there is provided a writing utensil comprising: a tubular body; a cap; means detachably securing the cap to the body; guide means detachably secured to the body; first and second refills axially slidable in the guide means; and a cam cylinder in the cap, which can engage the refills to project or retract the refills; characterised in that the cam cylinder is pivotable in the cap and clip is attached to the cam cylinder, so that pivotal movement of the clip causes the cam cylinder to project or retract the refills. According to a still further aspect of the invention there is provided a writing utensil comprising: a tubular body; a cap; guide means detachably secured to the body; first and second refills axially slidable in the guide means; a cam cylinder in the cap, whereby rotation of the cam cylinder causes the cam cylinder to engage with the refills to alternately project and retract the refills; characterised in that the cam cylinder is rotatably secured to the body by a core shaft formed integrally with the cam cylinder, and axially slidable within the guide means to allow a knocking operation of the cam cylinder. Preferred embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 is a section through a writing utensil according to an embodiment of the present invention; Figure 2 is a sectional view taken along the line II-II of Figure 1; Figure 3 is a sectional view taken along the line III-III of Figure 1; Figure 4 is an enlarged front view of a guide post; Figure 5 is a side view of Figure 4; Figure 6 is a bottom plan view of Figure 4; Figure 7 is a sectional view taken along the line VII-VII of Figure 5; Figure 8 is a sectional view taken along the line VIII-­ VIII of Figure 5; Figure 9(A) is a sectional view showing a rearward outer cylinder; Figure 9(B) is a sectional view taken along the line IX-­ IX of Figure 9(A); Figure 10 is a sectional view taken along the line X-X of Figure 9(A); Figures 11(A) and (B) are views illustrating different modifications of a cam engaging projection; Figure 12 is a front view, partly in section, showing internal construction of the writing utensil; Figure 13 is an enlarged sectional side view of Figure 4 of the upper part of the writing utensil; Figure 14 is a sectional view taken along the line Y-Y of Figure 12; Figure 15 is a sectional view of a writing utensil according to another embodiment of the present invention; Figure 16 is an enlargement of part of the sectional side view of Figure 15, showing detail of the body cap, and intermediate connecting cylinder of the writing utensil; Figure 17 is a perspective illustration of the intermediate connecting cylinder of Figure 16; Figure 18 is a side view of the body 101 and an intermediate connecting cylinder in Figure 16, separated; Figure 19 is a sectional side view correspond to Figure 18; Figure 20 is a sectional view taken along the line VI-VI of Figure 19; Figure 21 is a sectional view taken along the line VII-­ VII of Figure 19; Figure 22 is a sectional view taken along the line VIII-­ VIII of Figure 19; Figure 23 is a sectional view taken along the line IX-IX of Figure 20; Figure 24 is a schematic illustration of a pen attaching shaft shown in Figure 15; Figure 25 is a front view of a core of the writing utensil shown in Figure 15; Figure 26 is a sectional view taken along the line X-X of Figure 25; Figure 27 is a sectional view taken along the line Y-Y of Figure 26; Figure 28 is a developed explanatory view illustrating functions of a cam cylinder; Figure 29 is a sectional view of a writing utensil according to a modification of the embodiment of Figure 15; Figure 30 is a developed sectional view of a cam cylinder; Figure 31 is a sectional side view showing the writing utensil according to another embodiment of the present invention; Figure 32 is a side view of an internal mechanism of the writing utensil of Figure 31; Figure 33 is an enlarged plan view showing a guide post; Figure 34 is a sectional view taken along the line I-I of Figure 33; Figure 35 is a sectional view taken along the line II-II of Figure 31; Figure 36 is an explanatory view showing a mechanism for restricting a rotation of a cap of the writing utensil; Figure 37 is an explanatory view similar to Figure 36; Figure 38 is a partly sectional view showing a pen-­ holder; Figure 39 is a sectional view taken along the line III-­ III of Figure 31; Figure 40(A) is a front view showning a slider; Figure 40(B) is a side view of Figure 40(A); Figure 41 is a front view of a cam cylinder; Figure 42 is a sectional view taken along the line IV-IV of Figure 41; Figure 43 is a sectional view taken along the line V-V of Figure 42; Figure 44 is a developed explanatory view illustrating functions of a cam cylinder; Figure 45 is a view, in the same section with tht of Figure 39, showing another example of a slider; Figure 46 is a side view showing a guide post modified in respect of a mechanism for restricting a transfer of a cam cylinder; Figure 47 is a front sectional view of Figure 46; Figure 48 is a sectional view taken along the line VI-VI of Figure 46; Figure 49 is a front view showing a cam cylinder modified in respect of the mechanism for restricting a transfer of a cam cylinder; Figure 50 is a sectional view taken along the line VII-­ VII of Figure 49; Figure 51 is a sectional view taken along the line VIII-­ VIII of Figure 50; Figure 52 is a developed explanatory view illustrating functions of the cam cylinder of Figure 49; Figure 53 is a developed view showing another cam cylinder modified in respect of the mechanism for restricting a transfer of the cam cylinder; Figure 54 is a sectional view of a writing utensil showing yet another modification of the mechanism for restricting a transfer of the cam cylinder; Figure 55 is a sectional view showing the guide post of Figure 54; Figure 56 is a plan view illustrating a state in which a cam cylinder is fitted into the guide post of Figure 55; Figure 56 is a sectional view taken along the line X-X of Figure 55; Figure 58 is a sectional view showing the cam cylinder of Figure 54; Figure 59 is a sectional view taken along the line XI-XI of Figure 58; Figure 60 is a front view of a cam cylinder showing another example of the mechanism for restricting a transfer of the cam cylinder; Figure 61 is a developed explanatory view illustrating functions of the cam cylinder of Figure 60; Figure 62 is a longitudinal sectional view showing another modified writing utensil; Figure 63 is a sectional view showing the upper part of the body of the writing utensil of Figure 62; Figure 64 is a front view showing the sheath of Figure 62; Figure 65 is a sectional view showing the writing utensil according to another embodiment of the present invention; Figure 66 is an enlarged front view showing an upper part of Figure 65; Figure 67 is a sectional view showing a correlated construction of an intermediate cylinder and a body of the writing utensil; Figure 68 is a sectional view taken along the line VI-VI of Figure 67; Figure 69 is a sectional side view taken along the line VII-VII of Figure 67; Figure 70 is sectional view taken along the line VIII-­ VIII of Figure 67; Figure 71 is a sectional view taken along the line V-V of Figure 68; Figure 72 is a partly sectional view showing a pen-­ holder; Figure 73 is a front view showing a cam cylinder; Figure 74 is a sectional view taken along the line X-X of Figure 73; Figure 75 is a sectional view taken along the line XI-XI of Figure 74; Figure 76 is a front view of a clip shown in Figure 65; Figure 77 is a side view of Figure 76; Figure 78 is a top view of Figure 76; Figure 79 is a partly sectional view showing the relation between a cap and a clip illustrated in Figure 65; Figure 80 is a developed explanatory view illustrating functions of modified cam cylinder; Figure 81 is a side view, partly in section, showing a modification of the writing utensil of the Figure 1 embodiment; Figure 82 is an enlarged sectional side view of the upper part of the modified writing utensil of Figure 81, from the side of the mechanical pencil holder; and Figure 83 is an enlarged sectional view of the cap of Figure 81 viewed from the side of the ball point pen-holder. A first embodiment of the present invention will be described with reference to Figures 1 to 14 of the drawings. Referring to Figure 1, a writing utensil comprises a lower outer cylinder or hollow body part 1, a guide post 2 mounted on the upper end of the body 1; an upper outer cylinder or cap 3 rotatably attached to guide post 2, which cap 3 is axially slidable by a knocking operation, and two refills 4, 5 slidably guided in guide post 2, and each carrying a slider 6,7 which has cam surface 61, 71, which can engage with a projection 34 on the inside of cap 3. The lower end of guide post 2 is cylindrical and, as is shown in Figures 4 to 8, has, sequentially; on threaded portion 20 by which the lower end of post 2 is screwed in to an internal threaded portion 10 at the upper end of the body 1; a projecting annular portion 21, a lower face of which abuts against the top end of body and the outside diameter of which is substantially the same as outside diameter of the body 1; and a cylindrical portion 22 of a smaller diameter than annular portion 21. The cylindrical portion 22 has substantially the same outside diameter as threaded portion 20. Further the post 2 has a reactangular sectioned shaft portion 23 integrally with, and projecting from the upper end of the cylindrical portion 22 in a coaxial manner. An integral cylindrical portion 24 surmounts the upper end of the guide shaft portion 23, in a coaxial manner, and an integral upper engagement shaft portion 25 extends co-axial from and is smaller in diameter than upper cylindrical portion 24. The engagement shaft portion 25 is forked, and has locking claws 25a. Also in post 2, two slide holes 26 and 27 extend through the externally threaded portion 20 and the annular portion 21 at the symmetrical positions with respect to the center of the shaft 23, to cut-away parts 22a,b of cylindrical portion 22, as shown in Figures 6 and 7. A rotation-stop 28 projects radially from annular portion 21, and which restricts the range of relative rotation cap 3 as will be described hereafter. The rotation-stop 28 is accommodated in a large internal diameter portion 30 at the lower end of cylindrical cap 3. As best seen in Figures 9a and b, and 10 on the inside surface of cap 3, are a pair of parallel axial slide grooves 31 and 32 the lower ends of which open on to the upper end of the large internal diameter portion 30, and which permit a knocking operation of the cap 3, as will be explained hereinafter. Moreover, an extreme end portion 33 of a partition wall between these axial slide grooves 31 and 32 forms a rotation-stop 33, extending from a step 30a into the large internal diameter portion 30 of cap 3. In use, the rotation-stop 33 can abut against either side of rotation-stop 28 on post 2, to restrict rotation of cap 3, about guide post 2. Under such conditions of restricted rotation, when stop 33 abuts rotation-stop 28, the upper end of rotation-stop 28 is opposite to the lower, open end of one of the axial slide grooves 31 and 32. As a result, rotation-stop 28 can enter into either of axial slide grooves 31 and 32 to permit cap 3 to advance by a knocking operation. As will become apparent, the axial length of the axial slide grooves 31 and 32, i.e. each distance (a) defined between the step 30a, portion 30, and the upper end of the axial slide grooves 31 and 32, corresponds to a knocking margin for sending out a lead in mechanical pencil holder 4. Thus, the cap 3 can be downwardly transferred by the distance (a) to allow a knocking operation. It is to be noted that where only one of the two refills is a mechanical holder, only one of the axial slide grooves 31 and 32 need be provided for knocking the mechanical pencil holder. The provision of two grooves allows for the utensil to be used with two mechanical pencil holders. It will become apparent when the stop 33 is positioned opposite to stop 28 by rotation of the cap 3, the mechanical pencil holder 4 and the ball point pen-holder 5 are retracted, and held contained in the utensil. In that situation, the step 30a of portion 30 abuts against the upper end of stop 28, so that cap 3 cannot advance. Thus, stop 28 prevents the cap 3 from a play the axial direction. A cam engaging projection 34 for engaging cam surfaces 61 and 71 of sliders 6 and 7 (see Figures 1, 3, 9(A) and 10) extends from midway to the top end on the inside of the cap 3. The cam engaging projection 34 is diametrically opposite stop 33 on the inside of cap 3, as shown in Figure 9(A) and Figure 10. The end of cam engaging projection 34 is formed into a suitable profile, which can move and engage smoothly with the respective cam surfaces 61 and 71 of sliders 6 and 7, for example the profile may be a sharply tapered one as shown in Figure 11(A), a round one is shown in Figure 11(B), or the like figure. Towards the upper end of cap 3 is a small diameter shaft insert hole 35, and an internally threaded portion 36 above shaft insert hole 35. The refills 4, 5 illustratively a mechanical pencil holder 4 and the ball point pen-holder 5, are inserted into the slide holes 26 and 27 of guide post 2, respectively, to be axially slidable. As shown in Figure 12, mechanical pencil holder 4 has a lead guide 41 detachably connected to the lower end of a lead pipe 40, which is inserted into one (26) of the slide holes. Accordingly, if the lead pipe 30 is pulled out from the lead guide 41 after removing the guide post 2 from the body 1, required leads can be inserted in lead pipe 40. In such mechanical pencil holder 4, a lead feeding mechanism 42 is disposed on the lower end of the lead guide 41. The lead feeding mechanism 42 comprises a lead chuck 43, a chuck fastening ring 44, and a first spring or elastic member 45 as a cushioning means. On the other hand, the ball point pen-holder 5 is detachably connected to the lower end of a pen attaching shaft 50 which is inserted slidably in the other slide hole (27) through a pen-holder 51. The pen-holder 51 has a small diameter cylindrical portion 51A with which can receive lead pipe 40 of mechanical pencil holder 4, and a larger diameter cylindrical portion 51B which can receive the end of ball point pen-holder 5, so that either can be detachably connected. Accordingly, interchangeability of the refills is obtained so if ball point pen-holder 5 is pulled out from the cylindrical portion 51B, a separate mechanical pencil holder having a different lead diameter or type from that of the mechanical pencil holder 4 can be fitted to the small diameter meshing cylindrical portion 51A. The sliders 6 and 7 are connected to the respective upper ends of mechanical pencil holder 4 and ball point pen-holder 5, respectively. These sliders 6 and 7 are generally semi-cylindrical, as shown in Figures 2, 3 and 14, with a rectangular groove 60, 70 on their flat face and when put together they form a generally circular-shaped whole, with the axial grooves 60 and 70 on the inside, see e.g. Figure 14. The cam surfaces 61 and 71 on the outside of slides 6 and 7, are gradually curved and inclined from the lower end of each slider towards the top, and so that with slides together they symmetrical. At the top end each cam surfaces 61 and 71 has locking portions 61a and 71a, as shown in Figures 1 and 14, which have a concave profile, matching the shape of the cam engaging projection 34. The axial grooves 60 and 70 of slides 6 and 7 embrace shaft portion 23, so that sliders 6 and 7 can be individually axially slide along the shaft 23, together with the mechanical pencil holder 4 or ball point pen-holder 5, respectively. An elastic members in the form of spring 46 and 52 is interposed between the top of the cylindrical portion 21 of the guide post 2 and the under side of the respective slider 6, 7 to urge the mechanical pencil holder 4 and ball point pen-holder 5 upwards. As a result, the tops of the sliders 6 and 7 abut against the underside of the upper circular portion 24 at the top of shaft 23, which limits upward movement of the sliders. To assemble the writing utensil, the guide post 2, the mechanical pencil holder 4 and the ball point pen-holder 5 as well as the sliders 6 and 7 and the other posts are put together, then threaded portion 20 of the guide post 2 is screwed into externally threaded portion 10 of the body 1, and then the lower end side of the cap 3 is rotatably fitted on the upper end of the body 1. At this time the shaft insert hole 35 of the cap 3 is forced onto the engaging shaft portion 25 of the guide post 2 from the top, so that locking claw 25a passes through the shaft insert hole 35 and engages with the upper end surface about the shaft insert hole 35, so retaining the cap 3 in place. A top machine screw 8 is screwed into the internally threaded portion 36 at the top of cap 3, so that thrust shaft portion 8a of the top machine screw 8 is inserted between the forks of engaging shaft portion 25, to make engagement of the locking claw 25a within the shaft insert hole 35 more positive and firm. Also, a securing ring of a clip 9 is fastened to cap 3 by means of the top machine screw 8. Thus, the final assembly of the writing utensil takes place with the sliders 6 and 7 retracted and urged by their own elastic members 46 and 52 so that adjacent lower end surfaces of the cam surfaces 61 and 71 on the sliders 6 and 7 are forcibly engaged with the cam engaging projection 34 on cap 3. In other words, as shown in Figure 13, the lower ends of cam surfaces 61 and 71 become a tapered short-circuit when the sliders 6 and 7 are fitted together at the retracted position. Under the condition shown in Figures 1, 12 and 13 where both lower ends of cam surfaces 61 and 71 engage with cam engaging projection 34, the respective sliders 6 and 7 are retracted so that both the mechanical pencil holder 4 and the ball point pen-holder 5 are maintained at a retracted and contained position in the body 1. On the other hand, when the cam engaging projection 34 is engaged with one or other of the locking portions 61a and 71a at the top of cam surfaces 61 and 71, by the rotation of the cap 3, the engaged slider 6 or 7 is advanced so that the corresponding refill is kept at a writing position, projecting from the body 1. Thus the mechanical pencil holder 4 and the ball point pen-holder 5 are alternately moved fowards and backwards by means of a rotation of the cap 3, while they may be contained together within the body of the utensil. It is to be understood that since sliders 6 and 7 have a rotation restricting function for the cap 3, the rotation-stop projection 33 which is incorporated with cap 3 may be omitted. More specifically, the cap 3, which is held rotatable in place by the engagement of locking claw 25a with the shaft insert hole 35, is rotated so the cam engaging projectiong 34 slides towards the top of either of the cam surfaces 61 and 71 and engages either of locking portions 61a and 71a and either of the sliders 6 and 7 advances so that they are axially offset from one another and a side the other slider 6 or 7, being in a retracted position, is exposed, so cam engaging projection 34 engages with that exposed end surface, thereby restricting rotation. With such an arrangement cap 3 can be rotated by about 180 degrees. Next, the operation of the above described embodiment of the writing utensil will be described. With the mechanical pencil holder 4 and the ball point pen-holder 5 both retracted and contained in the body 1 shown in Figures 1 and 12, when the cap 3 is rotated the cam engaging projection 34 slides urgingly on, for example, the cam surface 61 of the slider 6 on the side of the mechanical pencil holder 4 from the lower end thereof to the top and locking portion 61a, whereby slider 6 is advanced against the elastic member 46. As a result, the mechanical pencil holder 4 being integral with slider 6 and advances to be projected from the body 1, and when the cam engaging projection 34 engages with the locking portion 61a of cam surface 61, the mechanical pencil holder 4 is maintained in a writing position. In this writing position, when the cap 3 is knocked, the slider 6 moves downwardly further through the cam engaging projection 34 engaging with the end locking portion 61a of cam surface 61, whereby a lead of the mechanical pencil holder 4 is fed out. When cap 3 is reversely rotated from this writing position, engagement of cam engaging projection 34 with the locking portion 16a is released, so that the cam engaging projection 34 rotates along the direction where cam engaging projection 34 leaves cam surface 61, whereby slider 6 moves upwards by means of the urging force of the elastic member 46, and, because of this upward movement of the slider, the mechanical pencil holder 4 is retracted and contained in the body 1, and at the contained position, cam engaging projection 34 has allowed cam surface 61 to return to a state where the lower end of cam surface 61 is engaged with the cam engaging projection 34. When cap 3 is rotated in the opposite direction from that initially mentioned above, cam engaging projection 34 slides urgingly on the cam surface 71 of the slider 7 on the side of the ball point pen-holder 5, towards the locking portion 71a, whereby slider 7 moves downward to project the ball point pen-holder 5 to a writing position, Eventually, the cam engaging projection 34 engages with the locking portion 71a of the writing position, whereby the ball point pen-holder 5 is maintained at a locked state. In the state just described, when the cap 3 is reversely rotated, the slider 7 for the ball point pen-holder 5 is retracted into the body of the writing utensil. In the position where the mechanical pencil holder 4 has been projected and the ball point pen-holder 5 has been retracted by means of a rotation of cap 3 in one direction, the cam engaging projection 34 is engaged with a side surface of the slider 7 for ball point holder 5 (or stop 33 engages stop 28), whereby the rotation of cap 3 in that direction is restricted. On the other hand, cam engaging projection 34 engages with the side surface of slider 6 (or stop 33 engages the other side surface of stop 28) at a position where the mechanical pencil holder 4 has been retracted and the ball point pen-holder 5 has been projected by a rotation of cap 3 in the other direction, whereby rotation of the cap 3 in the other direction is restricted. Figures 81 to 83 illustrate a modification of the first embodiment shown in Figures 1-14 and common reference numerals designate like or corresponding parts throughout these views. In the modified embodiment an excessive writing pressure moderating mechanism 500 is mounted on the lower part of slider 6 for a mechanical pencil holder 4, as shown in Figures 81 and 82, which functions to prevent breakage, slippage and the like of a lead in such a way that the whole of the mechanical pencil holder 4 is retracted into body 1 when an excessive writing pressure is applied to the lead of the mechanical pencil. The mechanism 500 comprises a peg 510 fitted to the top of lead pipe 4 and movably into a space 62 defined in the lower outside part slider 6, and an elastic member in the form of a spring 412 for moderating excessive writing pressure, disposed in the space 62 between the peg 510 and a wall 62a of space 62, which urges peg 510 and the mechanical pencil holder 4 downwards in a retractable manner. It is to be noted that the elastic member is not limited to a cushion spring, but any elastic member made of sponge, rubber, plastics and the like may be used so far as such member has a prescribed elastic force. While the elastic member 512 which is separate from the slider 6 has been inserted into the space in the above embodiment, such elastic member may be a one-piece molding together with the slider 6. In this case, whole the slider 6 is formed of a synthetic resin such as polyacetal, polypropylene, or the like, and the elastic member 512 which has been subjected to one-piece molding in the space 62 may have any construction of a profile such as branched, strip-like, bent strip-like, or slit-like etc. profile so that such an elastic member has an elastic force which can urge downwardly the peg 510. It is to be understood that a modulus of elasticity of the elastic member 512 is smaller than that elastic member 45. Meanwhile a ball point pen-holder 5 is detachably connected to the cover end of pen attaching shaft 50 inserted slidably into either of slide holes 37 through a pen-holder 51 as shown in Figures 81 and 83. In case of the ball point pen-holder 5, breaking of a lead or the like due to an excessive writing pressure action need not be taken into consideration, so that no retraction of the ball point pen-holder 5 is required. Thus, an upper larger diameter portion 51C of the pen-holder 51 is contained immovably in space in the slider 7 as shown in Figure 83. As described above, since the pen-holder 51 is directly inserted in the fixed to the slider 7, the number of parts cn be reduced so that the cost for such a writing utensil can be reduced. Opening to the spaces 62 and 72 are defined on the sides of the respective sliders 6 and 7, and it is arranged that peg 510 and the upper larger diameter portion 51C of the pen-holder 51 may be inserted through these openings. According to the above construction, when an excessive writing pressure is applied to a lead of a mechanical pencil during a writing or the like operation, cushioning elastic member 512 having a smaller modulus of elasticity than that of the elastic member 45 is compressed so that whole the mechanical pencil holder 4 is retracted inside the writing utensil, whereby breakage of the mechanical pencil lead or slippage thereof due to opening of a chuck can be prevented. As described above, according to the present embodiment, since refills are urged downwards by means of an elastic member for moderating an excessive writing pressure in a retractable manner, when such an excessive writing pressure is applied to a refill lead, whole the refill is retracted inside the writing utensil. Hence, the present embodiment of the invention provides such an advantage of preventing breakage and slippage of the refill lead. Another embodiment of the present invention will be described hereinbelow. Referring to Figure 15, a writing utensil generally comprises lower outer cylinder or body 101, and a junction or inermediate cylinder 102, detachably connected to the top of body 101, and a cap 107 secured through a central stem 183 to intermediate cylinder 102 to allow relative axial movement. Within the body 102 are contained two refills, mechanical pencil holder 103, and a ball point pen holder 104, which can slide axially in guide holes 123, 124 in intermediate cylinder 102. A cam cylinder 109 in cap 107, is arranged to engage the upper ends of the refills 103, 104 to project and retract those refills, as will be described hereinafter. The body 101 and intermediate cylinder 102 are interconnected by circular portion 120, of smaller diameter, at the lower end of cylinder 102 which is a detachable, force fit into a top cylindrical portion 110, of body 101, as shown in Figures 15 - 18. Each of two stops 111, on the inner surface of cylindrical portion 110 is received into a corresponding groove 121 defined on the outer surface of lower end 120 of intermediate cylinder 102. The two stops 111, and grooves 121, are diametrically opposite one another as shown in Figures 19 and 21. Thus intermediate cylinder 102 non-rotatable engages with body 101. The lower circular portion 120 of intermediate cylinder has a central shaft receiving hole 122 and two slide holes 123 and 124 for receiving refills (Figures 20 and 21) which are positioned on opposite sides of shaft hole 122 while being displaced by 90 degrees from the axial engaging groove 121, as shown in Figure 17 to 21. Into these slide holes 123 and 124, mechanical pencil holder 103 and ball point pen-holder 104 are axially slidably received as shown in Figure 15. As shown in Figures 20 and 21, slide holes 123 and 124 are formed so that the mechanical pencil holder 103 and the ball point pen-holder 104 may be smoothly slid while bending (being flexible) when they are advanced and projected, by making the dimension of the holes in the direction of bending larger, thereby defining an elliptical profile which becomes gradually larger in diameter towards the top of each hole. As shown in Figures 15 and 20, on the inside wall at the bottom of slide holes 123 and 124, are respective annular projections 123a, 124a, which retains the lower ends of the elastic members, in the form of springs, 134 and 142, and thereby prevent the mechanical pencil holder 103 and the ball point pen-holder 104 slipping from the slide holes 123 and 124. Regarding mechanical pencil holder 103, a lead guide 131 is detachably connected to the lower end of a lead pipe 130 inserted in slide hole 123 as shown in Figure 15. With the utensil disassembled lead pipe 130 can be pulled off from lead guide 131, so that leads can be supplied to lead pipe 130. A lead feeding mechanism 132 is disposed at the lower end of the lead guide 131. Furthermore, the lead feeding mechanism 132 has a lead chuck fastening ring (not shown) as well as a first elastic member (spring) 133. The ball point pen-holder 104 is detachably connected to the lower end of the pen mounting shaft 140 inserted slidably into the other slide hole 124, through a penholder 141 as shown in Figure 24. The generally cylindrical penholder 141 has, an upper cylindrical portion 141A which engagingly receives small diameter extension 140a at the bottom end of the pen mounting shaft 140 in the manner of a press fit, or by adhesive bonding or the like manner; a middle, cylindrical portion 141B of a larger diameter than upper portion 141A, which is capable of receiving the lead pipe 130 of mechanical pencil holder 103; and a lower larger diameter cylindrical portion 141C to which is detachably connected the mechanical pencil holder 104. The ball point pen-holder 104 held in the lower cylindrical portion 141C can be pulled out and replaced by a mechanical pencil holder which may differ from mechanical pencil holder 103 in a diameter of lead used or a type thereof, and which would be received by the middle diameter portion 141B. Thus interchangeability of refills is enhanced. At the top end of each of mechanical pencil holder 103 and ball point pen-holder 104 are fitted cam engaging members (sliders) 105 and 106, which forcibly engage with a cam surface of cam cylinder 109, which will be described hereinbelow. As shown in Figures 19, 20 and 23, these sliders 105 and 106 are received in axial guide grooves 125 and 126 defined on the inside surface of intermediate cylinder 102, whereby the sliders can slide smoothly axially. Mechanical pencil holder 103 and ball point pen-holder 104 are urged upwards towards a retracted position by the elastic members (springs) 134 and 142 which act between annular projections 123a, 124a and sliders 105, 106, respectively. Also sliders 105 and 106 on mechanical pencil holder 103 and ball point pen-holder 104, are pressed against and engage with cam surfaces of cam cylinder 109, by means of elastic members 134 and 142, as will be described below. A semicylindrical extension 128 is formed at the top of intermediate cylinder 102 as shown in Figures 18 and 19. One side surface of semicylindrical extension 128 forms a stepped stopper surface 128a on a ball point pen feeding side for restricting rotation of cam cylinder 109 in one direction, (described hereunder), while the other side surface of semicylindrical extension 128 forms a stopper surface 128b on a mechanical pencil feeding side which restricts a rotation of cam cylinder 109 in the other direction. The stopper 128a has a stepped portion 128c for restricting downward movement of cam cylinder 109 on the ball point pen feeding side. In this construction, a distance (a) is defined between the top surface 102a of the cylinder 102 and top of stepped portion 128c of extension 128 as shown in Figures 15 - 17. The distance (a) corresponds to a knocking margin for feeding a lead from mechanical pencil holder 103. Cap 107 is provided with a clip 170, and is axially slidably and rotatably mounted on the top end portion of intermediate cylinder 102. A core 108 is inserted into the cap 107 by means of a press fit, or the like manner, so that relative rotation is not permitted. Cam cylinder 109 is formed integrally on the lower end of core 108, and is inserted into the intermediate cylinder 102 to be rotatable and axially slidable. As shown in Figures 15 - 17 as well as Figures 25 and 27, core 108 has cylindrical extension 180, and an integral larger diameter, stepped portion 181, and stepped portion 181 engages the inside of cap 107. One manner for such engagement is to have a convex ribs 107a integrally formed on the inside surface of cap 107 towards the top, slidably fitted into and engaged with, corresponding concave indentations 181a in outside surface of stepped portion 181, both of which extend axially. As a result, core 108 engages with cap 107, so that cap 107 and core 108 can rotate together as well as being axially slidable together. Modifications such as having the concave indentations on the cap 107, whilst having the convex portions on the stepped portion 181, and that they are a press fit in and engaged with each other, are also applicable. Moreover, a one-piece molding of the cap 107, and core 108, and the integral cam cylinder 109 is also possible, through such modification is not illustrated in the accompanying drawings, and in most cases, the number of parts can be reduced and steps for assembly can be simplified. The core 108 has an integral intermediate shaft portion 182 of a smaller diameter than adjacent stepped portion 181, and the cam cylinder 109 extends from the lower end of intermediate shaft portion 182, so cam cylinder 109 rotates with core 108 and is axially slidable therewith. An integral projection 184 extends downwards from the lower side if the intermediate shaft portion 182 as shown in Figure 17. The projection 184 functions to restrict a rotation and axial movement of cam cylinder 109, by the projection 184 engaging with stopper surfaces 128a and 128b, and intermediate cylinder 102. The core 108 also has an integral central shaft 183 extending through cam cylinder 109, from the lower end of intermediate shaft portion 182. The shaft 183 is inserted into the top of intermediate cylinder 102, and is axially slidable in shaft receiving hole 122 of intermediate cylinder 102. Hence, the cam cylinder 109 being integral with core 108 is contained in intermediate cylinder 102 in a rotatable and axially slidable manner. A machine screw 185 is screwed into the lower end of shaft 183 as shown in Figures 15 - 17, so that the shaft 183 and the cam cylinder 109 cannot slip out from the intermediate cylinder 102. A press fitting member having an anchor shape may be used in place of machine screw 185, and pressingly fitted to and meshed with the extreme end of the core shaft 183. As shown in Figures 15 - 17 and in addition, Figures 25, 26 and 27, cam cylinder 109 has curved and inclined cam surfaces 191 and 192 on the opposite sides of lower end thereof, a lower locking portion 193 at the lower end these curved and inclined cam surfaces, and a top locking portion 194 on the curved and inclined cam surfaces 191 and 192. The sliders 105 of mechanical pencil 106 are urged against and engaged with the curved and inclined cam surface 191, 192 by elastic members 134 and 142, respectively. Accordingly, when the sliders 105 and 106 are kept at an intermediate position on the curved and inclined cam surfaces 191 and 192 by means of rotation of the cam cylinder 109, as shown in Figure 28, the mechanical pencil holder 103 and the ball point pen-holder 104 are contained and maintained in the body 101 at retracted positions. Upon rotation cam cylinder 109 so that the slider 105 of the mechanical pencil holder 103 engages with the locking portion 193, the mechanical pencil holder 103 is projected and at the same time, the slider 106 of the ball point pen-holder 104 engages with the top locking portion 194, whereby the ball point pen-holder 104 is maintained at the retracted and contained position. Conversely, when the slider 105 of the mechanical pencil holder 103 and the member 106 of the ball point pen-holder 104 engage with the locking portion 194 and the locking portion 193, respectively, the mechanical pencil holder 103 and the ball point pen-holder 104 are maintained at the contained position and the projected position, respectively. Thus, the mechanical pencil holder 103 and the ball point pen-holder 104 are alternately projected and retracted by rotation of the cam cylinder 109, whilst they can be both contained simultaneously at an intermediate position. As shown in Figures 15 and 16, eraser 186 is contained in cylindrical extension 180, of core 108 and a knocking cap 187 detachably fitted to the cylindrical portion 180, and covers eraser 186. Next, operations of a writing utensil according to the aforesaid embodiment will be described. When the cap 107 is rotated in either direction, the incorporated cam cylinder 109 is also rotated in that direction by means of core 108, so that, in one direction slider 105 of the mechanical pencil holder 104 moves along the curved and inclined cam surface 191 towards the locking portion 193 as shonw in Figure 28, while at the same time, the cam engaging member 106 of the ball point pen-holder 104 transfer towards the upper end locking portion 194 on the other curved and inclined cam surface 192, whereby the ball point pen-holder 104 moves upwards. This upward movement is effected by means of an urging force of the elastic member 152. The slider 105 mechanical pencil holder 103 engages locking portion 193, and slider 106 on the ball point pen-holder 104 engages locking portion 194, the projection 184 engages with the stopper surface 128b. As a consequence, further rotation of cam cylinder 109 in that direction is restricted, and at the same time mechanical pencil holder 103 is maintained, projected from the lower end of the body 101, whilst the ball point pen-holder 104 is contained and maintained in the body 101 at its retracted position. While projection 184 engages stopper surfaces 128(b), if the cap 107 or the knocking cap 187 at the top of cap 107 is knocked, the core 108 and cam cylinder 109 can be downwardly transferred by a distance (a). The slider 105 of the mechanical pencil holder 103 is advanced by means of the cam cylinder 109 in the above case, so that the lead pipe 130 is pushed downwardly to operate the lead feeding mechanism 132, thereby feeding a lead. When the cap 107 is rotated from this situation in the other direction, the incorporated cam cylinder 109 rotates therewith, so that the slider 105 on the mechanical pencil holder 103 moves upwards by means of an urging force of the elastic member 134 along the curved and inclined cam surface 191 of cam cylinder 109, and at the same time the slider 106 on the ball point pen-­ holder 104 pressed downwards by means of the other curved and inclined cam surface 192 of cam cylinder 109. As a result, the ball point pen-holder 104 moves downwards go be projected, and at that position the cam engaging member 106 is engaged with the lower locking portion 193, and at the same time projection 184 engages with the stopper surface 128a, whereby a rotation of cam cylinder 109 is restricted, whilst engagement of projection 184 with the stepped portion 128c restricting downward movement of core 108 and cam cylinder 109. The ball point pen-holder 104 is maintained at a writing position where it is projected from the body 101, and the mechanical pencil holder 103 is simultaneously retracted to be contained. Figure 39 illustrates a modification of this embdiment of the writing utensil according to the present invention wherein the intermediate cylinder 102 in the aforesaid embodiment is omitted and the body 101 is extended. The cam cylinder 109, integral with the core 108, is attached to body 101 as in the case of the previous embodiment. Accordingly, like parts of the present embodiment are shown by coresponding reference numerals in the aforesaid embodiment, and a detailed explanation of the construction and the functions of the present embodiment is omitted. Figure 30 illustrates another modification of the writing utensil wherein the cap 107 is integrally constructed with the cam cylinder 109. More specifically, the upper end portion of the cam cylinder 109 is formed with the inside of the top end of the cap 107 by means of a one-piece molding. In this case, securing of a one-piece molding of the cap 107 together with cam cylinder 109 and core shaft 183 by means of machine screw 185 is, of course, possible, but shaft 183 can be separately formed from the cam cylinder 109, the top end of shaft 183 being received in a shaft receiving hole 109a at a top of cam cylinder 109, from below, and a locking claw 183a formed on the top end of the core shaft 183 engages with top surface of hole 109a, whereby cam cylinder 109 is connected with core shaft 183. Thus, a one-piece molding of the cap 107 and the cam cylinder 109, as well as a molding for the core shaft 183 can very simply be carried out. Still another embodiment of the present invention will be described hereinbelow. Referring to Figures 31 and 32, a writing utensil comprises reference numeral 201 a lower forward outer cylinder or body 201, an upper outer cylinder or cap 203 connected through a guide post 202 to body 201. The cap 203 is axially slidable, so as to be capable of knocking operation, and is rotatable relative to body 201 and guide post 203. Within the body 201 are two refills, a mechanical pencil holder 204 and ball point pen holder 205, which carry a respective slider 206, 207, and which can slide axially in guide holes 225, 226 in guide post 202. A cam cylinder 208 in cap 203 is arranged to alternately project and retract the two refills. The guide post 202 is detachably connected to the top of the body 201, by means of a hollow externally threaded portion 220, at the lower end of the guide post 202 threadedly engaging with an internally threaded portion 210 at the top of the body 201, and the lower side of a lower circular stepped portion 221 of guide post 202 of larger diameter than threaded portion 220, abutting against the top end of body 201. Although the illustrated engagement of guide post 202 and body 201 in the present embodiment is by screw fit, such engagement may be effected by means of a press fit or the like manner. It is to be noted that the outside diameter of lower circular stepped portion 221 of guide post 202 is smaller than that of the body 201. As shown in Figure 33, guide post 202 is provided with an integral shaft portion 222 extending coaxially from stepped portion 221. The shaft portion 222 is formed into a flat plate of a rectangular profile having a thinner thickness S shown in Figure 34 than a breadth H shown in Figure 33. For this reason, the axial length of the cap 203 as well as a diametrical dimension can be shortened so that the whole writing utensil can be made compact. The guide post 203 also has an upper circular stepped portion 223 which is integrally formed at the top of shaft portion 222, and an integral, forked, engaging shaft portion 224 of a smaller diameter than upper portion 223 surmounts the circular stepped portion 223, coaxially. The engaging shaft potion 224 is provided with locking claws 224a. Also, two slide holes 225 and 226 for receiving refills are formed in lower circular stepped portion 221 between the inside of hollow portion 220 and the upper surface of portion 221, and are symmetrically disposed on opposite sides of shaft portion 222. A locking projection 227 for restricting a rotation and axially knocking movement of cap 203 is integrally formed on the outside surface of, and towards the top of, the lower circular stepped portion 221, as shown in Figures 31, 33 and 35 - 37. A circumferential slide groove 230 for engagingly receiving with the locking projection 227 is formed on the inside surface at the lower end of the cap 203 as shown in Figures 35 and 36, to cooperate in restricting axial movement and rotation of the cap 203. The slide groove 230 is formed into a substantially semicircular arcuate profile so that locking projection 227 can be reversibly rotated by 180 degrees and, in this embodiment, an axial slide groove 230a is formed at one end of the slide groove 230, see Figure 36. The axial slide groove 230a allows for knocking a mechanical pencil holder 204 as will be described hereunder and as shown in Figures 31 and 36, a distance equal to a knocking margin (b) in the upper end of the guide post 202 or another knocking margin (a), which is longer than that of the former margin (b), between the upper end of the slide groove 230a and the top of the locking projection 227. Thus, when the locking projection 227, engages top of slide groove 230a at an advanced position of the cap 203 by a knocking operation, a further downward movement of the cap 203 is restricted. It is to be understood that the axial slide groove 230a is formed only at one end of the circumferential slide groove 230 in the present embodiment. This is because there is no need of knocking the ball point pen-holder 205, so that only the mechanical pencil holder 204 need be knocked. However, it may be necessary that both refills are capable of being knocked, e.g. where both the refills are as mechanical pencil holders. In that case two axial slide grooves 230a and 230b may be connected with and formed on opposite ends of the circumferential slide groove 230 as shown in Figure 37. The mechanical pencil holder (first refill) 204 and the ball point pen-holder (second refill) 205 are inserted in the slide holes 225 and 226 of guide post 202, respectively to slide axially as shown in Figure 31. Mechanical pencil holder 204, has a lead guide 241 detachably connected to the lower end of a lead pipe 240 inserted into one slide hole 225, and a lead can be supplied to lead pipe 240 by removing the cap 203, by unscrewing the guide 202 from the body 201, and drawing lead pipe 240 out from the lead guide 241. A lead feeding mechanism 242 is disposed at the lower end of the lead guide 241. Furthermore, the lead feeding mechanism 242 has a lead chuck and a chuck fastening ring (not shown) as well as a first elastic member (spring) 243. The ball point pen-holder 205 is detachably connected to the lower end of a pen attaching shaft 250 slidably inserted into the other slide hole 226, by means of a penholder 251 as shown in Figure 38. The penholder 251 has three portions: an upper connecting cylindrical portion 251A to which is attached an extension shaft portion 250a at lower end of pen attaching shaft 250, by means of press fit, adhesive bonding or the like manner, a central cylindrical portion 251B of a larger diameter than the upper portion 251a, and into which can be fitted a lead pipe (240) of a mechanical pencil holder (240), a lower, larger diameter cylindrical portion 251C to which is detachably connected the top of ball point pen-holder 205. With this pendholder 251, if the ball point pen-holder 205 connected to the lower, portion 251C is pulled out, another mechanical pencil holder, which may differ from mechanical pencil holder 204 in a diameter of lead or a type thereof can be connected with the central cylindrical portion 251B, so that refills can be interchanged. To the end of each of the mechanical pencil holder 204 and ball point pen-holder 205, are connected sliders 206 and 207. As shown in Figure 39, the sliders 206 and 207 are generally, symmetrical semi-cylindrical, with an axial slide groove 260, 270 formed on the flat surface. These axial slide grooves 260 and 270 have a width corresponding to breadth H of shaft portion 222, and of guide post 202, and the shaft is sandwiched in these grooves so that the sliders can slide separately in the axial direction, while holding shaft portion 222 between them. Thus, opposite side walls of the axial slide grooves 260 and 270 are formed into hooking leg portions 260a, 260a, and 270a, 270a, respectively, which can slide along the opposite side surfaces of shaft portion 222 in the axial direction, while engaging with the shaft upon rotating thereof. Regarding the sliders 206 and 207, because the bottom of the axial slide grooves are in planar contact with the flat surfaces of the shaft portion 222, and hooking leg portions 260a, 260a and 270a engage with a side surface of guide post shaft portions 222 under rotational load, the sliders 206 and 207 can smoothly and stably slide without slipping out from shaft portion 222. From the centre of the outside curved surface of each of sliders 206 and 207, extends an integral cam engaging projection 261 and 271, (as shown in Figures 31, 32, 39 and 40). The top of cam engaging projections 261 and 271 are formed into a sharply tapered profile as shown in Figures 32 and 40 or a circular or the like profile (Not shown). The mechanical pencil holder 204 and ball point pen-­ holder 205 are always urged in the retracted direction by means of elastic members (springs) 244 and 252 interposed between the top of the lower circular stepped portion 221 of guide post 202 and the underside of sliders 206 and 207. As a result, the top of cam engaging projections 261 and 271 of the respective sliders 206 and 207, are pressed into contact and engage with a cam surface of the cam cylinder 208 as will be described hereinafter. The cam cylinder 208 has, see Figures 41, 42 and 43, has lower curved and inclined cam surfaces 283, 284, which are symmetrical, and the lower junction of which is a lock portion or notch 285 while at the upper junction of which is a locking portion or flat 286. The upper cylindrical portion 282 of the cam cylinder is internally threaded, and axial grooves are formed on the outer surface of the cam cylinder. A restricted diameter, shaft receiving hole 280 is formed inside the cam cylinder.. The cam cylinder 208 is for alternately projecting and retracting mechanical pencil holder 204 and ball point pen-holder 205 is fitted onto the top side of shaft 222 of the guide post 202, to which are attached the refills as a unit, in a reversibly rotatable manner by means of the engaging shaft portion 224 at top end of shaft portion 222 being received into shaft insert hole 280 from below, and the locking claw 224a engages with the top surface of cam cylinder about shaft receiving hole 280, whereby the cam cylinder 208 can rotate around the engaging shaft portion 224 as its centre. Under the condition where the top surface about shaft receiving hole 280 engages with locking claw 224a as shown in Figure 31, a distance (b) is defined between the upper side of upper, circular stepped portion 223 and the undersurface of about shaft receiving hole 280. The distance (b) is a knocking margin for feeding a lead in the mechanical pencil holder 204 and which is equal to or a shorter length than the above-mentioned distance (a). Accordingly, cam cylinder 208 can transferable by the distance (b) in the axial direction thereof, and thereby allowing a knocking operation. Furthermore, can cylinder 208 is engaged to rotate with the cap 203, by means, integral stops 231 on the inside surface at top of the cap 203, (see Figures 31 and 43) which fit into the engage with the axial groove 281 on the outside surface of the cam cylinder 208 (see Figure 31 and Figures 41 - 43). A threaded portion 290 of a machine screw 209, is screwed into the internally threaded portion 282 of cam cylinder 208. An integral thrust shaft portion 293 extend, from the centre portion of top machine screw 209 between the forks of engaging shaft portion 224, so that the locking claws 224a, are more positively and firmly pressed into engagement. The top machine screw 209 also fastens ring portion of a clip 300 to the top of the cap 203. Next, operations of the writing utensil according to the above embodiment will be described hereunder. In an intermediate position where the refills 204 and 205 are retracted into the body 201, the cam engaging projection 261 of the slider 206 and the cam engaging projection 271 of the slider are both pressed into engagement with the curved and inclined cam surface 283, 284, by means of elastic members (springs) 244 and 252. When the cap 203 is rotated in one direction, the incorporated cam cylinder 208 is also rotated and the cam engaging projection 261 of the slider 206 on the mechanical pencil holder 204 moves downwards on the curved and inclined cam surface 283 (Figure 44). In this case, a rotational load of the cam cylinder 208 acts on slider 206, but this load is absorbed because the hooking leg portions 260a, 206a of slider 206 engage with the opposite side surfaces of the shaft portion as shown in Figure 39. Thus, the slider 206 slides smoothly along shaft portion 222, and the mechanical pencil holder 204 moves downwards. Meanwhile, the cam engaging projection 271 of the slider 207 in the ball point pen-holder 205 moves on the other curved and inclined cam surface 284 towards the upper locking portion 286, so that the ball point pen-holder 205 moves upwards, urged by the elastic member 252. When the cam engaging projection 261 of the mechanical pencil holder 204 and the cam engaging projection 271 of the ball point pen-holder 205 engage with the lower and upper locking portion 285, 286, respectively, the mechanical pencil holder 204 is maintained at a position, projecting from the lower end of the body 201, while the ball point pen-holder 205 is contained and kept at its retracted position in the body 201. In this condition, when the cap 203 is knocked, the cam cylinder 208 moves downwards with the cap 203 so that the slider 206 on mechanical pencil holder 204 is moved by cam cylinder 208. Hence, the lead pipe 240 is pushed downwards and the lead feeding mechanism 242 operates, thereby sending out a lead. From this situation, when the cap 203 is rotated in the other direction, the cam cylinder 208 also rotates in the other direction, so that the cam engaging projection 261 on the mechanical pencil holder 204 moves upwards along the curved and inclined cam surface 283 of cam cylinder 208 and the cam engaging projection 271 on the ball point pen-holder 205 side moves downwards on the other curved and inclined cam surface 284 of cam cylinder 208. As a result, the ball point pen-holder 205 advances to be projected and at that position, the cam engaging projection 271 engages with the lower locking portion 285, so that it is maintained at that position, while the mechanical pencil holder 204 is retracted and contained. Figure 45 illustrates a modification of the sliders 206 and 207, wherein one each of the hooking leg portions 260a and 270a is removed compared to sliders 206 and 207 shown in Figure 39, so that the modified sliders 206 and 207 have one hooking leg portion 260a and 270a each, and which are opposite one another. The hooking leg portions 260a and 270a are disposed on side portions of the sliders 206 and 207 so that the hooking leg portion 260a of slider 206 on the mechanical pencil holder 204, engages with one side surface of the shaft portion 222, by means of the rotational lod of the cam cylinder 208 when the cam cylinder 208 is rotated to project the mechanical pencil holder 204 (rotation in the direction indicated by arrow (A) in Figure 45), while the hooking leg portion 270a of the slider 2097 on the ball point pen-holder 205 engages with the other side surface of the shaft portion 222 by means of the rotational friction or load of cam cylinder 208, when the cam cylinder 208 is rotated to project the ball point pen-­ holder 205 (rotation in the direction indicated by arrow (B) in Figure 45). Hence, the hooking leg portions 260a and 270a engage alternately with the side surface of the guide post shaft portion 222 by means of rotational load of the cam cylinder 208 in case of a movement to project the mechanical pencil holder 204 or the ball point pen-holder 204 or the ball point pen-holder 205. Therefore, the sliders 206 and 207 do not slip out from the shaft portion 222 due to the rotational load of cam cylinder 208, so that sliders 206 and 207 can stably and smoothly slide along shaft portion 222. Other examples of mechanisms for restricting a transfer of the cam cylinder are shown in Figures 26 - 48, and Figures 49 - 51, in which the guide post 202 and the cam cylinder 208 are modified. First, a modified construction of the guide post 202 will be described in conjunction with Figures 46 - 48. Upper circular stepped portion 223 of the guide post 202 is formed with a diameter equal to a breadth H of the guide post shaft portion 222, and an integral stopper projection 228 for restricting a rotation of the cam cylinder 208 and a transfer in the axial direction, extends from the outside of the upper circular stepped portion 222. On one hand, a modified construction of the cam cylinder 208 will be described in conjunction with Figures 49 - 52. A circumferential slide slot 287 for restricting a transfer of the cam cylinder 208 and in which engages stopper projection 228, is defined midway along outside surface of cam cylinder 208. The slide slot 287 is semicircular about the long side of cam cylinder 208, and axial slide slot 288 extends upwards from one end of the semicircular slot 287 to allow a knocking opertion. In the axial slide slot 288, a distance (c) defined between the top end thereof and the top end of the stopper projection 228 (Figure 52) is formed to be equal to or longer than the distances (a) and (b) shown in Figure 31. Furthermore, for easy assembly of cam cylinder 208 and the guide post 202, a guide slot 289 extends axially downwards from midway along semicircular slide slot 287. The stopper projection 228 of the guide post 202 is fitted into the guide slot 289 from the inside when the guide post 202 is inserted into the shaft receiving hole 280 of cam cylinder 208. More specificlly, when the locking clay 224a of the guide post 202 is inserted into and through the shaft receiving hole 280 with the stopper projection 228 engages in the guide slot 289, from the inside, the cam cylinder 208 is rotatably meshed and engaged with the engaging shaft portion 224 of the guide post 202. When the stopper projection 228 abuts against the top wall of the circumferential slide slot 287, and the stopper projection can slide in circumferential slide slot 287 by a rotation of the cam cylinder 208, and cam cylinder 208 can be rotated by 180 degrees. Accordingly, the rotation-stop or locking projection 227 and the circumferential slide groove 230 on the cap 203 (Figure 31, 36) become necessary, and may be omitted. Furthermore, with stopper projection 228 at the end of the axial slide slot 288 in the circumferential slide slot 287, the stopper projection 228 can be slid in the axial slide slot 288 to permit a down transfer of cam cylinder 208 at the time of knocking for feeding a lead for the mechanical pencil holder 204. In the present modified embodiment, therefore, when the stopper projection 228 engages with an end of the circumferential slide slot 287 by rotating cam cylinder 208 with the cap 203, in either direction, the rotation of cam cylinder 208 in that direction is restricted. When the cam cylinder is rotated so that the stopper projection 228 is by axial guide slot 288 the mechanical pencil shaft 204 projects from the lower end of the body 201 and the ball point pen-holder 205 is contained in its retracted position in the body. In this condition, when the cap 203 is knocked, the incorporated cam cylinder 208 moves downwardly and stopper projection 228 moves upwards in the axial slide slot 288 of the cam cylinder 208, to allow that downward movement. The lead pipe 240 of the mechanical pencil holder 204 is pushed downwards by means of cam cylinder 208, so that the lead feeding mechanism 242 operates to feed out a lead. When the knocking state of cap 203 is released, the cam cylinder 208 transfers upwards by means of the force of the elastic members 244 and 252, the stopper projection 228 engages with the lower end of the axial slide slot 288 and can slide in the circumferential slide slot 287. When cap 203 is rotated in the other direction from the above desdribed situation, the incorporated cam cylinder 208 also rotates in that other direction, the stopper projection 228 slides in the circumferential slide slot 287 towards other end of the slot, and at the same time the cam engaging projection 261 of the slider 206 on the mechanical pencil holder 204 transfers on the curved and inclined cam surface 283 the lower end locking portion 285 to the upper locking portion 286, while the cam engaging projection 271 of the slider 207 in the ball point pen-holder 205 transfers on the other curved and inclined cam surface 284 in the reverse direcion. As a result, the ball point pen-holder 205 is projected, whilst the mechanical pencil holder 204 is retracted to be contained, and the stopper projection 228 eventually engages with the other end of the circumferential slide slot 287, whereby rotation of cam cylinder 208 in the other direction is restricted. Figure 53 illustrates another modified embodiment of a mechanism for restricting a transfer of a cam cylinder in a writing utensil having a first second mechanical pencil holder 204, 205, with different diameter leads 208. Specifically, two axial slide slots 288 and 288a are provided, one at each end of the circumferential slide slot 287 to obtain a knocking margin for feeding a lead at the projected positions of both the first and second mechanical pencil holders 204 and 205. Under the circumstances, when the incorporate cam cylinder 208 with the cap 203 in either direction, the cam engaging projection 261 of the slider 206 on the first mechanical pencil holder 204 transfers on the curved and inclined cam surface 283 towards the lower locking portion 285, and the cam engaging projection 271 belonging to the other mechanical pencil holder 205 system transfers on the other curved and inclined cam surface 284 towards the upper locking portion 286, whereby the first mechanical pencil holder 204 moves downwards, while the second mechanical pencil holder 205 moves upwards, and when the stopper projection 228 engages with the end of circumferential slide slot 287, rotation of cam cylinder 208 in that direction is restricted, so that the first mechanical pencil holder 204 projects from the lower end of the body 201 and at the same time, the second mechanical pencil holder 205 is contained in the body 201 at its retracted position. In this condition, when the cam cylinder 208 is transferred downwards by a knocking operation of the cap 203, a lead is sent out for the first mechanical pencil holder 204. When cam cylinder 208 is rotated in the other, reverse direction, the first mechanical pencil holder 204 retracts, while the second mechanical pencil holder 205 advances to be projected, and the cam cylinder 208 can be transferred downwards by a subsequent knocking operation, whereby a lead is sent out from the second mechanical pencil holder 205. Thus, the first and second mechanical pencil holder 204 and 205 are alternately projected and retracted by means of the reversible rotation of the cam cylinder 208. When, by means of a rotation of cam cylinder 208 in either direction, the stopper projection 228 engages with an end of the circumferential slide slot 287 with either of the first and second mechanical pencil holders 204 and 205 projected whilst the other mechanical pencil holder is retracted, further rotation of the cam cylinder 208 in that direction is restricted. Moreover, a rotation of cam cylinder 208 in the other direction is restricted at a position where either of mechanical pencil holders 204 and 205 is retracted, whilst the other mechanical pencil holder is projected by means of a rotation of the cam cylinder 208 in that direction. Furthermore, when cam cylinder 208 is rotated by about 90 degrees, the cam engaging projections 261 and 271 of the sliders 206 and 207 in the first and second mechanical pencil holders 204 and 205 are maintained in respective intermediate portions of the curved and inclined cam surfaces 283 and 284 on the opposite sides of the cam cylinder 208. As a consequence, mechanical pencil holders 204 and 205 are both maintained in the body 201 at their contained positions, respectively. Figures 54 to 59 illustrate another modified embodiment of a mechanism for restricting a transfer of a cam cylinder wherein rotation of the cam cylinder 208 is restricted by an engagment of an integral stop projection 280a on the inside surface of the cam cylinder 208, with a locking groove 224a defined on the guide post 202. More specifically, the rotation-stop projection 280a extends on the inside surface of the cam cylinder 208 and just below the shaft receiving hole 180. A notched engaging groove 223a with which rotation-stop projection 280a engages to restrict rotation of cam cylinder 208, is defined on the outside of the upper circular stepped portion 223 of the guide post 202 as shown in Figures 55 - 57. The notched engaging groove 223a is substantially semicircular, so that rotation-stop projection 280a can rotate by 180 degrees. To secure the cam cylinder 208 and cap 203A locking projections 208a are formed on the outside, upper end of cam cylinder 208, and fit into and engage with the locking grooves 203a defined on the inside surface of the cap 203. Alternatively, a locking groove may be formed on the outside surface, of the upper end of cam cylinder 208, and a locking projection formed on the inside surface of the cap 203. Figures 60 and 61 illustrate another modified embodiment of a mechanism for restricting a transfer of a cam cylinder wherein rotation of the cam cylinder 208 is restricted by an engagment of rotation-stop projection 280a extending from the inside circumferential surface of the cam cylinder 208 with the cam engaging projections 261 and 271 of the sliders 206 and 207. Accordingly, the engaging groove 223a of the upper circular stepped portion 223 on the guide post 202 is not required in the present embodiment unlike the above modified embodiment. More specifically, in the present modification, a rotation-stop projection 280a is formed on an upper locking portion for locking the cam engaging projections 261 and 271 of the sliders 206 and 207 in case of retracting the refills 204 and 205 as shown in Figure 60. Therefore, the rotation-stop projection 280a engages with the cam engaging projection 261 and 271 to restrict a reversible rotation of the cam cylinder 208, so that excessive rotation of the cam cylinder 208 can be prevented in the present modified embodiment. Also in the present modified embodiment, a knocking margin (b) is allowed between the cam engaging projection 261 and 271 and the upper locking portion 286, whereby either or both of the first and second refills 204 and 205 can be knocked (in this case, the upper locking portion 286 is formed into a shape indicated by a solid line in Figure 60 and 61), or either or both of them can be held against knocking (in this case, the upper end locking portion 286 is formed into a shape indicated by a dotted line in Figure 60 or 61). Figures 62 - 64 illustrate a modified embodiment of a construction for connecting the body 201 with the guide post 202 wherein a cylindrical portion 222A is disposed on the lower end of the lower circular stepped portion 221 of the guide 202, with outside diameter being equal to the inside diameter of the body 201, and a plurality of integral locking projections 222B and protrude from the outside surface of the cylindrical portion 222A. On the upper end of the body 201 are an axial guide slots 211 each for receiving one of locking projections 222B, from the top and a circumferential locking hole 212 communicating with the lower end of axial guide slot 211 to receive the respective locking projection 222B from the axial guide slot 211 as shown in Figure 63. On the inlet side of each circumferential locking hole 212 is a locking stepped portion 213, and an inclined elastic locking piece 214 inclined on the lower side thereof. Hence, when locking projection 222B is pushed into axial guide hole 211 from the top end and the guide post 202 is rotated, locking projection 222N is pushed into the circumferential locking hole 212 and press fitted into and locked by locking stepped portion 213 by means of elastic force of elastic locking piece 214. As a consequence, the guide post 202 can be detachably connected to the body 201 in one-short manner. The other construction of the present modified embodiment than those described above is the same with the aforementioned embodiment, so that the same advantages can also be obtained. Another embodiment of the present invention will be described with reference to Figures 65 - 80, wherein a writing utensil has a lower outer cylinder or body 301, a junction or intermediate outer cylinder 302 connected to the top of the body 301. A cap 307 is detachably fitted to the top end of the intermediate cylinder 302. Refills, a mechanical pencil holder 303 and ball point pencil holder 302, and axially slidable within body 301 and guided in slide holes 323, 324 in the intermediate cylinder 302. A cam cylinder 309, contained in cap 307 and intermediate cylinder 302, is rotatable by clip 400 to project and retract the refills. The body 301 and intermediate cylinder 302 are connected by lower circular portion 320, of smaller diameter, of intermediate cylinder 302, being detachably forced into and connected with an upper end cylindrical portion 310 of body 301. As shown in Figures 69 and 70 the engagement is effected stop projections 311 disposed, symmetrically about the inside surface of upper cylindrical portion 310, which fit into axial engaging grooves 321 at symmetrical positions on the outisde surface of circular portion 320. Alternatively these members may be a screw fit. Thus, the intermediate cylinder 302 and body 301 are secured against relative rotation. As shown in Figures 67 - 70, lower circular portion 320 has a central shaft receiving hole 322, and two slide holes 323 and 324 for receiving refills at the positions where they sandwich shaft receiving hole 332, and are displaced by 90 degrees from axial engaging grooves 321 (see Figures 68 and 69). A mechanical pencil holder 303 (first refill) and a ball point pen-holder 304 (second refill) are inserted slidably into these slide holes 323 and 324 along the asxial direction thereof, respectively, as shown in Figure 65. As shown in Figures 68 and 69, slide holes 323 and 324 are formed so that mechanical pencil holder 303 and ball point pen-­ holder 304 may be smoothly slid while bending (being flexible) when advanced, by making holes larger in the bending direction to obtain an elliptical profile which becomes gradually larger in diameter towards the top. As shown in Figures 67 and 68, annular projections 323a, 324a extend about the lower end of slide holes 323 and 324, and which lock the lower ends of elastic members 334 and 342 and at the same time, prevent slipping-off of the mechanical pencil holder 303 and the ball point pen-holder 304 from the slide holes 324 and 325. Mechanical pencil holder 303, has a lead guide 331 detachably connected to the lower end of a lead pipe 330 which inserted in receiving hole 323. According to this construction, after pulling the intermediate cylinder 302 off from the body 301, when lead pipe 330 is pulled off from lead guide 331, leads can be supplied to lead pipe 330. A lead feeding mechanism 332 is disposed at the lower end of the lead guide 331. Furthermore, the lead feeding mechanism 332 has a construction comprising a lead chuck and a chuck fastening ring (not shown) as well as a first elastic member (spring) 333. Ball point pen-holder 304 is detachably connected to the lower end of the pen attaching shaft 340 inserted slidably into the other slide hole 324. In this case, ball point pen-holder 304 may be connected to the lower end of the pen attaching shaft 340 through a penholder 341 as shown in Figure 72. The penholder 351 has three portions: an upper connecting cylindrical portion 351A to which is attached an extension shaft portion 350a at lower end of pen attaching shaft 350, by means of press fit, adhesive bonding or the like manner, central cylindrical portion 351B of a larger diameter than the upper portion 351a, and into which can be fitted a lead pipe (340) of a mechanical pencil holder (340), and a lower, larger diameter cylindrical portion 351C to which is detachably connected the top of ball point pen-holder 305. To the respective top ends of the mechanical pencil holder 303 and ball point pen-holder 304 are connected cam engaging members (sliders) 305 and 306 which are forcibly engaged with a cam surface of a cam cylinder 309 which will be described hereinbelow. As shown in Figures 67, 68 and 71, these sliders 306 fit into axial guide grooves 325 and 326 defined on the inside surface of intermediate cylinder 302, whereby the sliders slide smoothly axially. Mechanical pencil holder 303 and the ball point pen-­ holder 304 are urged by the elastic member (springs) 334 and 342 interposed between annular projection 323a, 324a, and sliders 305, 306, respectively, towards the retracting direction. Cap 307 is detachably fitted to the top end of intermediate cylinder 302 along the axial direction thereof as shown in Figure 65. Within the cap 307, and intermediate cylinder 302 is core 308, which is rotatable and axially slidable. As shown in Figure 65 and Figures 73 - 75, the core 308 is provided with an eraser container 380, a flange 381 locking the lower end of a knocking cap 387 which will be described hereunder, an intermediate shaft portion 382 from which a cam cylinder 309 extends, a central core shaft 383 which extends from the lower end of the intermediate shaft portion 382 within the cam cylinder 309, and a pair of axial engaging projections 382 projecting from the outside surface of the intermediate shaft portion 382. A clip 400 engages with core 308 as shown in Figure 65. A free end of the clip 400 projects out from an annular hole or slot 307a about the circumferential surface of the cap 307 as shown in Figure 65 and Figures 76 through 79. The axial engaging projection 384 is provided for engaging the clip 400 with the core 308. More specifically, as shown in Figures 65, 76 - 79 (in Figure 78, the core 308 is indicated by a dotted line), the axially engaging projections 384 engage with an engaging groove 402 of the clip 400, with the core 308 passing through a receiving hole 401 of the clip 400. The clip 400 and the core 308 are thus rotated together while and the core 308 is allowed to be axially movable with respect to the clip 400. Accordingly, the core 308 and incorporated cam cylinder 309 can be rotated by a rotation of the clip 400, whereby the mechanical pencil holder 303 or the ball point pen-holder 304 is projected and retracted. In addition, since the core 308 is transferable in the axial direction, the core 308 can be knocked and a lead can be sent out in respect of the mechanical pencil holder 303. In this connection, clip 400 has a cam cylinder rotating function for rotating the cam cylinder 309 and the core 308 other functions than those belonging to a usual clip. In this case, a means for restricting a rotation of the clip 400, i.e. a retricting rotation of the cam cylinder 309, is effected between the clip 400 and annular slot 307a of the cap 307 through which the clip 400 projects, as shown in Figure 79. More specifically, as shown in Figure 79, the annular slot 307a is opened over more tha half of the circumference of the cap 307, whereby clip 400 is restricted to be rotatable about 180 degrees. as a result, the cam cylinder 308 is not excessively rotated. Furthermore, as shown in Figure 65, a distance a is maintained between the top of the clip 400 and underside of flange portion 381 of the core 308. This distance a corresponds to a length of a knocking claw or a longer length, so that the mechanical pencil holder 303 can send out a lead in a smooth manner. The cam cylinder 309 is provided with, a shown in Figures 73 and 74, curved and inclined cam surfaces 391 and 392, a lower locking portion 393 at the lower most ends of these curved and inclined cam surfaces 391 and 392, and an upper locking portion 394. The slider 305 of the mechanical pencil holder 303 and the slider 306 of the ball point pen-holder 304 are forcibly engaged with the curved and inclined cam surface 391 and the other curved and inclined cam surface 392 respectively by means of urging force of the elastic members 334 and 342, respectively. When the sliders 305 and 306 are maintained at intermediate positions on the curved and inclined cam surfaces 391 and 392 by means of a rotation of the cam cylinder 309 as shown in Figure 80, both the mechanical pencil holder 303 and the ball point pen-holder 304 are contained and maintained at a retracted position in the body 301. Furthermore, when the slider 305 of the mechanical pencil holder 303 engages with the lower locking portion 393, the mechanical pencil holder 303 projects and at the same time, the cam engaging member 306 of the ball point pen-holder 304 engages with the upper locking portion 394 so that the ball point pen-holder 304 is maintained at its retracted and contained position. On the other hand, when the slider 305 is engaged with the upper locking portion 394 and the slider 306 engages with lower locking portion 393, the mechanical pencil holder 303 is maintained at its contained position, while the ball point pen-holder 304 is maintained at its projected position. Thus, the writing utensil according to the present embodiment is arragned in such that the mechanical pencil holder 303 and the ball point pen-holder 304 are alternately projected and retracted, while they may also be simultaneously contained within the body of the writing utensil. In Figure 65, an eraser 386 is contained in a cylindrical portion 380, and 387 a knocking cap for covering eraser 386 and is detachably fitted to the eraser-containing cylindrical portion 380. Next, operations of the writing utensil according to the present embodiment will be described hereinafter. When the clip 400 is rotated in one direction, the cam cylinder 309 is rotated therewith and the slider of the mechanical pencil holder 304 moves downwards on the curved and inclined cam surface 391 towards the side of the lower end locking portion 393 as shown in Figure 80. At the same time, the slider member 306 of the ball point pen-holder 304 transfers on the other curved and inclined cam surface 392 towards the upper locking portion 394, so that the ball point pen-holder 304 moves upwards. Such upward movement is effected by an urging force of the elastic member 342. The slider 305 is engaged with the lower locking portion 393 and the slider 306 engages with upper end locking portion 394, and at the same time a side of the clip 300 is locked at the end of the annular slot 307a of the cap 307, as indicated by a dotted line in Figure 79. As a result, a rotation of cam cylinder 308 is restricted and at the same time, the mechanical pencil holder 303 is maintained at the position where it is projected from the extreme end of the body 301, while the ball point pen-holder 304 is contained and maintained at the retracted position in the body 301. Under these circumstances, when the knocking cap 387 at the top end of the cap 307 is knocked, the cam cylinder 309 moves downwards with core 308 by a distance a . When the slider 305 of the mechanical pencil holder 303 is moved by means of the cam cylinder 309 in this case, the lead pipe is pushed down, and a lead feeding mechanism 332 is operated to send out a lead. When the clip 400 is rotated in the other direction from the situation described above, the cam cylinder 309 rotates with the clip 400 in that other direction so that the slider member 305 on the mechanical pencil holder 303 moves upwards by means of the force of the elastic member 334 along the curved and inclined cam surface 391 of the cam cylinder 309 and at the same time, the slider 306 on the ball point pen-holder 304 is pressed downwards by means of the other curved and inclined cam surface 392 of the cam cylinder 309. The ball point pen-holder 304 advances and projects, and at this position, the slider 306 is engaged with the lower locking portion 393. At the same time, the other side surface of the clip 400 is locked at the other end of the annular groove 307a of the cap 307 as indicated by a dotted line in Figure 79. Thus, when axial engaging projection 384 in the axial direction is engaged with the stopper surface of the intermediate cylinder 302 on the side where the ball point pen is sent out, a rotation of cam cylinder 309 in the other direction is restricted. Then, the ball point pen-holder 304 is maintained at a writing position when it is projected from the body 301, and at the same time the mechanical pencil holder 303 is retracted and contained. While the body 301 is separately constructed from the intermediate cylinder 302 in the above embodiment, the construction may be such that the body 301 is made longer and the intermediate cylinder 302 is omitted.

Claims: 1. A writing utensil comprising: a tubular body (12); a guide post (2) detachably fitted to one end of the tubular body; a cap (3); means (2) rotatably securing the cap to body (1); first and second sliders (6, 7) which are axially slidable on the guide post (2); and first and second refills (4, 5) attached to the first and second sliders respectively; characterised in that cam surface (61, 71) are provided on the sliders (6, 7), and a cam engaging projection (34) provided on the cap (2), so that in use, when the cap is rotated, the cam surface of one or other of the sliders can engage with the cam engaging projection, and the corresponding refill be projected or retracted. 2. A writing utensil as claimed in claim 1, wherein there is cushioning means (510, 512) for resiliently supporting at least one of the refills (4, 5) against excessive writing pressure. 3. A writing utensil as claimed in claim 2, wherein the cushioning means includes a resilient member (512) held by one of the sliders (6, 7) and to which is attached one of the refills (4, 5). 4. A writing utensil comprising: a tubular body (201); a guide post (202) detachably fitted to one end of the tubular body (201); a cap (203); means (202) rotatably securing the cap (203) to the body (201); first and second sliders (206, 207) which are axially slidable on the guide post (202); and first and second refills (4, 5) attached to the first and second sliders respectively; a cam cylinder (208) in the cap (203) operative by rotation of the cap to engage the sliders (206, 207) to alternately project or retract the refills (204, 205) characterised in that a portion (222) of the guide post (202) one which the sliders (206, 207) slide, is rectangular, and each slider (206, 207) has at least one hook portion (260a, 270a) for engaging a side surface of that portion (222) of the guide post (202). 5. A writing utensil comprising: a tubular body (101); a cap (107); means rotatably securing the cap (102) to the body (101); guide means (102) detachably secured to the body (101); first and second refills (103, 104) axially slidable in the guide means; a cam cylinder (209) in the cap (107), whereby rotation of the cylinder causes the cam cylinder to engage with the refills (103, 104) to alternately project and retract the refills (103, 104); characterised in that the means rotatably securing the cap (107) to the body (101) includes a core shaft (183) formed integrally with the cam cylinder, and axially slidable within the guide means (102) so as to allow the cam cylinder (109) to by in the guide means (102) to allow a knocking operation of the cap (107). 6. A writing utensil as claimed in claim 5, wherein the cap (107), core shaft (183) and cam cylinder (109) are formed in one piece. 7. A writing utensil comprising: a tubular body (301); a cap (307); means (302) detachably securing the cap (307) to the body (301); guide means (302) detachably secured to the body (301); first and second refills (303, 304) axially slidable in the guide means; and a cam cylinder (309) in the cap (301), which can engage the refills (303, 304) to project or retract the refills (303, 304); characterised in that the cam cylinder (309) is pivotable in the cap (307) and clip (400) is attached to the cam cylinder (309), so that pivotal movement of the clip (400) causes the cam cylinder to project or retract the refills. 8. A writing utensil as claimed in claim 7, wherein the clip (400) projects through an aperture in the cap (307). 9. A writing utensil as claimed in any one of claims 1 to 8, wherein means (28, 30; 34, 67; 128, 184; 227, 230; 228, 287; 223a, 280a; 261, 271; 400, 307a) are provided for limiting rotation of the cap with respect to the body. 10. A writing utensil comprising: a tubular body (101); a cap (107); guide means (102) detachably secured to the body (101); first and second refills (103, 104) axially slidable in the guide means; a cam cylinder (109) in the cap (107), whereby rotation of the cam cylinder causes the cam cylinder to engage with the refills (103, 104) to alternately project and retract the refills (103, 104); characterised in that the cam cylinder is rotatably secured to the body (101) by a core shaft (183) formed integrally with the cam cylinder, and axially slidable within the guide means (102) so as to allow a knocking operation of the cam cylinder.

Inventors: EBINUMA, TADAYOSHI KOTOBUKI & CO., LTD., KAGEYAMA, HIDEHEI KOTOBUKI & CO., LTD., KOBAYASHI, SABURO KOTOBUKI & CO., LTD., KUBOTA, MASUO KOTOBUKI & CO., LTD., MITSUYA, YOSHIHIDE KOTOBUKI & CO., LTD., Ebinuma, Tadayoshi Kotobuki &amp; Co., Ltd., Kageyama, Hidehei Kotobuki &amp; Co., Ltd., Kobayashi, Saburo Kotobuki &amp; Co., Ltd., Kubota, Masuo Kotobuki &amp; Co., Ltd., Mitsuya, Yoshihide Kotobuki &amp; Co., Ltd.
Applicants: KOTOBUKI & CO., LTD.
Application year: 1987
Main classification: B43K24
IPC codes: B43K27, B43K24