WO2006004290A1

WO2006004290A1 - Chopsticks

Info

Publication number: WO2006004290A1
Application number: PCT/KR2005/000927
Authority: WO
Inventors: Mi Ja So
Original assignee: YOUNG WOO CO Ltd
Current assignee: YOUNG WOO CO Ltd
Priority date: 2004-03-31
Filing date: 2005-03-30
Publication date: 2006-01-12
Anticipated expiration: 2006-09-30

Abstract

The present invention provides chopsticks, which can provide functions of a spoon and table fork and of which grip and handling are facilitated. The present invention includes a pair of sticks (11 and 12) having upper ends joined together, a circular thumb grip (15) protruding from one side of the stick (11), a circular forefinger grip (13) protruding from a circumference of the stick (12), a circular middle finger grip (14) protruding from the circumference of the stick (12) under the forefinger grip (13), an elastic member (19) provided within a hinge (16) joining the sticks (11 and 12) together to elastically restrict an operational range of the hinge (16) so that the sticks (11 and 12) are folded or unfolded within a predetermined angle range, and a pair of semi-spoon shape members (20) provided to lower ends of the sticks (11 and 12) to extend in opposite directions, respectively and to form a spoon if a apir of the sticks (11 and 12) are folded.

Description

CHOPSTICKS

Technical Field

[1] The present invention relates to chopsticks, which can provide functions of a spoon and table fork and of which grip and handling are facilitated.

[2]

Background Art

[3] Generally, chopsticks consist of a pair of sticks having a circular, oval or rectangular cross-section each. And, there are various kinds of chopsticks differing in size for a child use, cooking and the like. And, there are metal chopsticks formed of a metal-based material such as Au, Ag, stainless steel, tin and the like or wooden chopsticks made of a bamboo, a weeping willow or the like.

[4] Babies at the age of 2-3 eat meals with forks and then grows up to use chopsticks gradually. Yet, most of children use forks before entering a primary school. In case of using chopsticks thereafter, they are apt to use the chopsticks incorrectly.

[5] The survey, which was performed on 252 adult residents (male: 131, female: 121) in a metropolitan area including Seoul and An- Yang by Professor Kim Pil-Soo, Daelim University, says that 62% of the adults fail in using chopsticks correctly.

[6] It means that only 38% of the adults can use chopsticks correctly. So, it is apparent that children are mostly unable to use chopsticks incorrectly by considering the fact that at least 50% of the adults are using chopsticks incorrectly. And, in the same survey, it is also known that most of elementary school students are not correctly using chopsticks.

[7] As a result of the survey which was conducted on 50 students at fifth grade about a method of using chopsticks by Professor Kim Pil-Soo, 20% of the students use the chopsticks correctly and 80% of the students fails in using the chopsticks correctly.

[8] A chopsticks handling keeps using sixty-four hand muscles and thirty articulations to help intelligence development of children and to prevent senile dementia. Hence, the chopsticks handling is suitable to the well-being trend but is regarded as insignificant. Yet, the correct chopsticks handling must be the precious cultural heritage needing to be handed down to the next generation.

[9] FlG. 1 is a perspective diagram of infant chopsticks according to a related art.

[10] Referring to FlG. 1, finger rings 3, 4 and 5 are attached to a pair of sticks 1 and 2.

And, upper ends of the sticks 1 and 2 are hinged together. Hence, fingers are inserted in the finger rings 3, 4 and 5, respectively so that the sticks 1 and 2 can move centering on a hinge 4 to help an infant grip the sticks 1 and 2 with a correct posture. Hence, the chopsticks is suitable for training or correcting a chopstick handling conducted by a beginner who is not accustomed to the chopsticks.

[11] However, since each of the finger rings 3, 4 and 5 of the related art chopsticks has a ring shape, the fingers fitted in the finger rings 3, 4 and 5 to use the chopsticks have difficult in being pulled out of the finger rings 2, 4 and 5.

[12] To pull out the fingers from the finger rings, the other hand is used in holding the sticks. Such an action is annoying. In using the chopsticks by one hand, a spoon is re¬ luctantly used or the other hand is used in holding the spoon. For instance, in case of a right-handed user, a right hand is used in holding the chopsticks and a left hand is used in holding the spoon. Unlike the educational intention, it is not preferable that the infant is accustomed to using the other hand in holding the spoon.

[13]

Disclosure of Invention Technical Problem

[14] Accordingly, the present invention is directed to chopsticks that substantially obviate one or more of the problems due to limitations and disadvantages of the related art.

[15] An object of the present invention is to provide chopsticks, in which chopsticks are simply transformed into a spoon and by which a user need not put down the chopsticks on a table to hold a spoon.

[16] Another object of the present invention is to provide chopsticks, by which the chopsticks can be easily gripped, by which the chopsticks can be easily put down and by which the chopsticks well stick to fingers in being used with an extra-effect of practicing finger muscles due to appropriate elasticity of the chopsticks moving in right-to-left direction.

[17] Another object of the present invention is to provide chopsticks, in which the chopsticks can be used as a spoon and a fork to provide the same roles thereof and by which a user can eat meals using one hand only.

[18] A further object of the present invention is to provide chopsticks, in which a body of the chopsticks are made of a metal-based material to have good endurance and by which an object can be easily picked up in using the chopsticks as a fork or spoon.

[19]

Technical Solution

[20] To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, chopsticks according to the present invention includes a pair of sticks 11 and 12 having upper ends joined together, a circular thumb grip 15 protruding from one side of the stick 11, a circular forefinger grip 13 protruding from a circumference of the stick 12, a circular middle finger grip 14 protruding from the circumference of the stick 12 under the forefinger grip 13, an elastic member 19 provided within a hinge 16 joining the sticks 11 and 12 together to elastically restrict an operational range of the hinge 16 so that the sticks 11 and 12 are folded or unfolded within a predetermined angle range, and a pair of semi-spoon shape members 20 provided to lower ends of the sticks 11 and 12 to extend in opposite directions, respectively and to form a spoon if a pair of the sticks 11 and 12 are folded. [21]

Advantageous Effects

[22] According to the present invention, by providing the semi-spoon type members to the lower ends of the sticks, respectively, the chopsticks can play a role as a spoon to avoid changing the chopsticks and the spoon alternately, whereby excellent usability and educational effect are provided.

[23] According to the present invention, by forming the one-side-open arc type thumb and forefinger grips, the chopsticks can be easily held or put down on a table. By providing the elastic member such as a spring to the hinge, the chopsticks adhere closely to the fingers suitably to facilitate handle the chopsticks and to prevent the chopsticks from being easily separated from the fingers. And, the elasticity of the elastic member accelerates finger muscle movements to enhance brain development of an infant user.

[24] According to the present invention, by configuring the chopsticks, the spoon and the fork altogether and by forming the protrusions on insides forming the spoon, the spoon is well assembled to enhance functionality as a spoon and the frictional force is raised to prevent the object picked up by the spoon from falling.

[25] According to the present invention, by forming the hinge part of the chopsticks with the plastic-based material and by forming the body of the chopsticks with the metal- based material such as stainless steel, the fork and spoon can be provided thinner. Therefore, the object can be picked up more effectively.

[26]

Brief Description of the Drawings

[27] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

[28]

[29] In the drawings:

[30] Fig. 1 is a perspective diagram of infant chopsticks according to a related art; [31] Fig. 2 is a perspective diagram of chopsticks according to one embodiment of the present invention; [32] Fig. 3 is a perspective diagram of a hinge and an elastic member in case of unfolding the chopsticks in Fig. 2; [33] Fig. 4 is a perspective diagram of a hinge and an elastic member in case of folding the chopsticks in Fig. 2; [34] Fig. 5 is an exploded perspective diagram of a hinge and an elastic member of the chopsticks in Fig. 2; [35] Fig. 6 is a perspective diagram of chopsticks according to another embodiment of the present invention; [36] Fig. 7 is a perspective diagram of chopsticks according to another embodiment of the present invention; [37] Fig. 8 is a perspective diagram of chopsticks according to another embodiment of the present invention; [38] Fig. 9 is a perspective diagram of chopsticks according to another embodiment of the present invention; and [39] Fig. 10 is a perspective diagram of chopsticks according to another embodiment of the present invention. [40]

Best Mode for Carrying Out the Invention [41] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. [42] Fig. 2 is a perspective diagram of chopsticks according to one embodiment of the present invention, Fig. 3 is a perspective diagram of a hinge and an elastic member in case of unfolding the chopsticks in Fig. 2, Fig. 4 is a perspective diagram of a hinge and an elastic member in case of folding the chopsticks in Fig. 2, and Fig. 5 is an exploded perspective diagram of a hinge and an elastic member of the chopsticks in

Fig. 2. [43] Referring to Figs. 2 to 5, upper ends of a pair of sticks 11 and 12 are joined together by a hinge 16 to unfold/fold the sticks 11 and 12 in a right-to-left direction. Finger grips 13, 14 and 15 are attached to the sticks 11 and 12 by fitting-in. Specifically, the stick 12 is fitted in a first fitting ring 17a and a forefinger grip 13 having a semicircular shape, i.e., an arc shape having an open outside, protrudes from a circumference of the first fitting ring 17a. [44] And, a middle finger grip 14 protrudes from a circumference of a second fitting ring

17b provided under the first fitting ring 17a to contact with and to move separately. [45] Moreover, a thumb grip 15 having an open arc shape protrudes from a cir- cumference of a third fitting ring 17c in which the other stick 11 is fitted.

[46] A forefinger and thumb are inserted in the arc shape forefinger and thumb grips 13 and 15 to facilitate to be detached from the sticks 11 and 12, respectively.

[47] The thumb grip 15, the forefinger grip 13, the middle finger grip 14 and the first to third fitting rings 17a to 17c can be formed of a rubber-based material such as a synthetic rubber having elasticity. Yet, either the thumb grip 15 and the third fitting ring 17c supporting the thumb grip 15 or the first and second fitting rings 17a and 17b supporting the forefinger and middle finger grips 13 and 14 can be built in one body of the stick 11 or 12 to be fixed thereto. Hence, The thumb grip 15, the forefinger grip 13, the middle finger grip 14 and the first to third fitting rings 17a to 17c can be formed of plastics. Meanwhile, the first and second fitting rings 17a and 17b support the forefinger and middle finger grips 13 and 14, respectively. And, a hand angle needs to be adjusted by turning the forefinger and middle finger grips 13 and 14 according to a feature of a user's hand. Hence, the third fitting ring 17c supporting the thumb grip 15 is preferably fixed to or built in one body of the stick 11 to enhance endurance.

[48] To prevent the first to third fitting rings 17a, 17b and 17c from being separated from the sticks 11 and 12, recesses to which the first to third fitting rings 17a, 17b and 17c are fixed are provided to outer circumferences of the sticks 11 and 12 to correspond to the first to third fitting rings 17a, 17b and 17c, respectively. And, the fitting rings 17a, 17b and 17c are fixed to the recesses, respectively so that the fitting rings 17 and 17b are rotatably provided not to move upward or downward.

[49] Meanwhile, an elastic member 19 is elastically provided within the hinge 16 joining the sticks 11 and 12 together. In this case, the elastic member 19 is an elastic spring such as a line spring and an elastic synthetic resin member. By such a configuration, the sticks 11 and 12 are appropriately unfolded or widened by an elastic force of the elastic member 19 within a range of a predetermined angle. As fingers inserted in the finger grips 13, 14 and 15 are elastically pressurized to adhere thereto, it is able to prevent the chopsticks in use from being easily separated from the fingers. Moreover, since a counter force against the elastic force generated from handling the sticks 11 and 12 is needed, finger muscles are automatically practiced to contribute to muscle de¬ velopment of children, brain activity acceleration and brain development.

[50] A pair of hemi-spoon type members 20 extending in opposite directions are provided to lower ends of the sticks 1 and 12, respectively. The hemi-spoon type members 20 do not play a role much in being used as chopsticks and do not interrupt the chopstick handling. Yet, if the sticks 11 and 13 are folded, the hemi-spoon type members 20 are combined to configure a spoon. Hence, the chopsticks according to the present invention provide the functions of the chopsticks and spoon. So, in it un¬ necessary to change chopsticks to a spoon in eating meals to avoid the annoying work of switching to hold chopsticks and spoon alternately. Besides, a chopsticks handling can be effectively trained.

[51] In the above explained embodiment of the present invention, it is preferable that finger muscle practice is enabled to an appropriate extent by appropriately adjusting the elasticity of the elastic member 19 to make the sticks 11 and 12 adhere closely to the fingers without unnatural use of the sticks 11 and 12. Optionally, in order for a pair of the sticks 11 and 12 not to be unfolded by the elastic member 19 in being stored, a separate locking or binding means for keeping a pair of the sticks 11 and 12 folded together can be further provided.

[52] A center shaft 29 of the hinge 16 is fitted in a central portion of the elastic member

19 to fix the elastic member 19 thereto. And, both leg portions of the elastic member 19 move within both gaps provided between arc type protruding members 30 and 31 protruding from a peripheral surface of the shaft, respectively. Namely, if the sticks 1 and 12 are bound together by being pressurized by fingers, one leg portion of the spring of the elastic member 19 is caught on the protrusion 32 fixed to the periphery of the hinge 16 to be relaxed inward. If the finger force is released, the tension of the elastic member 19 binding the sticks 11 and 12 together is released to extend the elastic member 19. Yet, since the hinge 16 just moves within the gaps provided by the arc type protruding members 30 and 31, and more particularly, within an inside of the gap provided in a lower part. Hence, an operational range of the hinge 16 corresponds to an angle range of the gap. For instance, the range of the gap is set to 10-45° and preferably, to 30°

[53]

Mode for the Invention

[54] Fig. 6 is a perspective diagram of chopsticks according to another embodiment of the present invention.

[55] Referring to Fig. 6, a forefinger grip 13 having a ring shape protrudes from one side of a circumference of a first fitting ring 17a provided to a circumference of a stick 12 at one side. And, a forefinger grip 14 having a ring shape protrudes from one side of a circumference of a second fitting ring 17b. And, a thumb grip 15 having a ring shape protrudes from a circumference of a third fitting ring 17c in which another stick 11 at the other side is fitted.

[56] Fig. 7 is a perspective diagram of chopsticks according to another embodiment of the present invention.

[57] Referring to Fig. 7, small circular protrusions 28 are provided to cross-sectional portions of insides of spoon type members 20, respectively to engage with each other. Alternatively, a multitude of saw-tooth type protrusions 28 can be configured to engage with each other. The protrusions raise a frictional force to prevent an object picked up by the chopsticks from falling. Meanwhile, if a pair of sticks 11 and 12 are folded so that spoon type members 20 provided to end portions of the sticks 11 and 12 configure a spoon shape, the protrusions 28 raise an assembled force of a spoon to enable an effective function of the spoon.

[58] Fig. 8 is a perspective diagram of chopsticks according to another embodiment of the present invention.

[59] Referring to Fig. 8, instead of the hinge 16 and the elastic member 19 shown in

Figs. 2 to 5, a U-type elastic member 19a joins sticks 11 and 12 together. Hence, the sticks 11 and 12 can be folded/unfolded in a right-to-left direction centering on the U- type elastic member 19a. Thus, the U-type elastic member 19a elastically folds/unfolds the chopsticks in the right-to-left direction. Like the hinge 16 and elastic member 19 shown in Fig. 2, the U-type elastic member 19a is configured to be unfolded within a range of a predetermined angle.

[60] In the embodiment of the present invention explained with reference to Figs. 2 to 5, the hinge 16 and sticks 11 and 12 are preferably formed of a plastic-based material to consider a user's age. Meanwhile, the rest configurations of the embodiment in Figs. 3 to 5 are the same of the former embodiment of the present invention in Fig. 2 except the U-type elastic member 19a.

[61] Fig. 9 is a perspective diagram of chopsticks according to another embodiment of the present invention.

[62] Referring to Fig. 9, sticks 21 and 22 are formed of a metal-based material such as a stainless steel except a hinge 16. Openings are formed at portions extending from the hinge 16 so that the sticks 21 and 22 are fitted in the openings to be fixed thereto. Al¬ ternatively, the sticks 21 and 22 can be attached to portions extending from the hinge 16 using an adhesive agent and the like. End portions of the sticks 22 are configured to form a spoon shape if combined together. And, a fork recess 27 is formed at each of the end portions of the sticks 21 and 22 to make the corresponding end portion diverge in two ways. Hence, the diverging end portion with the fork recess 27 can play a role as a fork individually. Or, the diverging end portions can play a role as a fork if the chopsticks are folded.

[63] Fitting rings 17a, 17b and 17c are provided to the sticks 21 and 22 made of a metal- based material. Recesses are formed on outer circumferences of the sticks 21 and 22 so that the fitting rings 17a, 17b and 17c are fitted in the recesses to be prevented from being separated from the sticks 21 and 22. The fitting rings 17a, 17b and 17c are rotatably fixed to the recesses provided to the outer circumference of the chopsticks to prevent the rotatable fitting rings 17a, 17b and 17c from being separated upward or downward. [64] Meanwhile, an elastic member 19 or 19a is elastically provided within the hinge 16.

In this case, the elastic member 19 or 19a is an elastic spring such as a line spring and an elastic synthetic resin member. In the drawing, the elastic member 19 is shown. Al¬ ternatively, the U-type elastic member 19a shown in fig. 3 can be used as the elastic member.

[65] Like the embodiments shown in Fig. 2 and Fig. 3, fingers fitted in the grips 13, 14 and 15 are elastically pressurized to adhere closely thereto. And, a repulsive force is generated from the elastic member 19 or 19a in a direction opposite to that of a finger pressurizing force, whereby the grips 13, 14 and 15 are prevented from being separated from the fingers.

[66] If there occurs a free play in the sticks 21 and 22 of the metal-based material except a direction in which the hinge 16 is unfolded, the spoon type members at the end portions fail in matching points to have difficulty in forming a complete spoon. Hence, in forming the metal-based sticks 21 and 22, a portion of the spoon type member 20 between an initial part and a middle part is formed thick and the rest portion is gradually thinned. Hence, even if there occurs a small free play, the points engage with each other to form the spoon.

[67] Alternatively, an initial portion of the spoon type member 20 is formed deep to be caught on a height of its sill.

[68] Fig. 10 is a perspective diagram of chopsticks according to another embodiment of the present invention.

[69] Referring to Fig. 10, like the former embodiment in Fig. 8, an end portion of a spoon type member 20, which diverges to be used as a fork, is provided to an end portion of each of a pair of sticks 24/26 and 23/25. And, the spoon type member 20 is formed of a metal-based material such as stainless steel and the like. Unlike the embodiment in Fig. 4, portions of the sticks 24 and 23 receiving fitting rings 17a, 17b and 17c are formed of a plastic-based material and the rest portions of the sticks 26 and 25 are formed of a metal-based material such as stainless steel and the like. The rest portions of the sticks 26 and 25 are joined to the former portions 24 and 24 in a manner of being fitted therein or attached thereto via an adhesive agent, respectively.

[70] The fitting rings 17a, 17b and 17c are rotatably fixed to recesses formed at the upper portions 23 and 24 of the sticks formed of the plastic-based material. Like the embodiments in Figs. 2 to 4, finger grips 13, 14 and 15 are provided to the upper portions 23 and 24 formed of the plastic-based material. Fitting holes are provided to lower ends of the upper portions 23 and 24 of the sticks formed of the plastic-based material so that the lower portions 25 and 26 formed of the metal-based material can be fitted in the fitting holes, respectively. And, the lower portions 25 and 26 of the sticks are fitted in the fitting holes of the upper portions 23 and 24 of the sticks formed of the plastic-based material or are attached to the upper portions 23 and 24 of the sticks using an adhesive agent to be fixed thereto, respectively.

[71] The end portions of the lower portions 25 and 26 of the sticks, like the con¬ figuration in Fig. 6, are combined together to form the spoon type member 20. A fork recess 27 is provided to each of the end portions of the lower portions 25 and 26 of the sticks to make the corresponding end portion diverge in two ways.

[72] Hence, the diverging end portion with the fork recess 27 can play a role as a fork in¬ dividually. Or, the diverging end portions can play a role as a fork if the chopsticks are folded.

[73] Fitting rings 17a, 17b and 17c are provided to the upper portions 24 and 23 of the sticks made of the metal-based material. Recesses are formed on outer circumferences of upper portions 24 and 23 of the sticks so that the fitting rings 17a, 17b and 17c are fitted in the recesses to prevent the rotatable fitting rings 17a, 17b and 17c to be prevented from being separated from the sticks. The fitting rings 17a, 17b and 17c are rotatably fixed to the recesses provided to the outer circumference of the chopsticks to prevent the rotatable fitting rings 17a, 17b and 17c.

[74] Meanwhile, an elastic member 19 or 19a is elastically provided within the hinge 16 of the chopsticks. In this case, the elastic member 19 or 19a is an elastic spring such as a line spring and an elastic synthetic resin member. In the drawing, the elastic member 19 is shown. Alternatively, the U-type elastic member 19a shown in Fig. 3 can be used as the elastic member.

[75] If there occurs a free play in the sticks of the metal-based material except a direction in which the hinge 16 is unfolded, the spoon type members at the end portions fail in matching points to have difficulty in forming a complete spoon. Hence, in forming the metal-based sticks, a portion of the spoon type member 20 between an initial part and a middle part is formed thick and the rest portion is gradually thinned. Hence, even if there occurs a small free play, the points engage with each other to form the spoon.

[76] Alternatively, an initial portion of the spoon type member 20 is formed deep to be caught on a height of its sill.

[77]

Industrial Applicability

[78] Accordingly, the present invention cab be used for a child or chopsticks beginner in practicing how to use the chopsticks. And, a user, who is already accustomed to the chopsticks, can use the chopsticks at her or his convenience.

Claims

[1] Chopsticks comprising: a pair of sticks 11 and 12 having upper ends joined together; a circular thumb grip 15 protruding from one side of the stick 11 ; a circular forefinger grip 13 protruding from a circumference of the stick 12; a circular middle finger grip 14 protruding from the circumference of the stick 12 under the forefinger grip 13; an elastic member 19 provided within a hinge 16 joining the sticks 11 and 12 together to elastically restrict an operational range of the hinge 16 so that the sticks 11 and 12 are folded or unfolded within a predetermined angle range; and a pair of semi-spoon shape members 20 provided to lower ends of the sticks 11 and 12 to extend in opposite directions, respectively and to form a spoon if a pair of the sticks 11 and 12 are folded.

[2] The chopsticks of claim 1, further comprising: a first fitting ring 17a rotatably provided to the stick 12 to support the forefinger grip 13 wherein the stick 12 is fitted in the first fitting ring 17a; a second fitting ring 17b provided to the stick 12 in the vicinity of the first fitting ring 17a to support the middle finger grip 14, the second fitting ring 17b in¬ dividually rotating wherein the stick 12 is fitted in the second fitting ring 17b; and a third fitting ring 17c rotatably provided to the stick 11 to support the thumb grip 15 wherein the stick 11 is fitted in the stick 11.

[3] The chopsticks of claim 1, wherein the sticks 11 and 12 are folded or unfolded using a U-type elastic member 19a in place of the hinge 16 and the elastic member 19.

[4] The chopsticks of claim 1, wherein each of the forefinger and thumb grips 13 and

15 protrudes to have an open-outside arc shape.

[5] The chopsticks of claim 1, wherein the thumb grip 12, the middle finger grip 14, the first fitting ring 17a and the second fitting ring 17b are formed of an elastic rubber-based material to be fitted in recesses formed one an outer circumference of the stick 12 and wherein the thumb grip 15 and the third fitting ring 17c supporting the thumb grip 15 are built in one body of the stick 11 to be fixed thereto.

[6] The chopsticks of one of claims 1 to 5, wherein the sticks 11 and 12 are formed of a plastic-based material.

[7] The chopsticks of claim 6, wherein a multitude of small circular protrusions 28 provided to inner cross-sections of the spoon shape members 20, respectively engage with each other.

[8] The chopsticks of one of claims 1 to 5, wherein a pair of holes are formed at portions extending from the hinge 16 and wherein the metal-based sticks 21 and 22 are fitted in or attached to the holes by an adhesive agent to be fixed thereto.

[9] The chopsticks of claim 8, wherein a fork recess 27 is provided to each of the spoon-shape members 20 to have an end portion diverge.

[10] The chopsticks of claim 8, wherein a portion of each of the metal-based sticks 21 and 22 extending right before the spoon-shape member 20 or to a middle part of the spoon-shape member 20 is formed thick.

[11] The chopsticks of one of claims 1 to 5, wherein an upper portion of each of the sticks extending to a portion receiving the fitting rings 17a, 17b and 17c is formed of a plastic-based material, wherein a lower portion of each of the sticks adjacent to the upper portion is formed of a metal-based material, and wherein the lower part is fitted in or attached to the upper portion by an adhesive agent to be fixed thereto.