JP3813657B2 - Sliding friction imparting mechanism and stick-shaped cosmetic material feeding container having the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mechanism for applying a frictional force between two objects that perform a sliding motion and a stick-shaped cosmetic material feeding container having a rotational weighting function based on the mechanism. In particular, the present invention relates to a sliding friction applying mechanism that obtains a frictional force by pressing an elastic bend piece against the other, and relates to a sliding friction applying mechanism that easily keeps the pressing force and the frictional force constant over a long period of time.
[0002]
[Prior art]
FIG. 5 is a cross-sectional view showing the internal structure of a stick-shaped cosmetic material feeding container (lipstick container) proposed by the inventors of the present application in Japanese Patent Application No. 6-288617. The bar-shaped decorative material feeding container 1 ′ shown in FIG. 5 includes four parts: a front cylinder sleeve 15, a push bar 21 with a support tray (chuck) 17, a female thread cylinder 41 ′, and an outer cylinder 90. Although not shown, a cap is attached to the tip of the outer cylinder 90.
[0003]
In the stick-shaped cosmetic material feeding container of FIG. 5, the support plate 17 and the push rod 21 are integrated (a push rod with a plate). A cosmetic material is filled in the front tube sleeve 15. The tail portion of the decorative material is inserted into the decorative material support tray 17 and supported. When the support tray 17 is driven by the push rod 21 and moves up and down in the front tube sleeve 15, the cosmetic material is drawn out and drawn from the front end port 11 of the front tube sleeve 15 accordingly.
[0004]
A detent groove 16 is cut in the longitudinal direction on the inner surface of the front sleeve 15. The anti-rotation groove 16 engages with an anti-rotation protrusion 20 projecting from the outer surface of the chuck 17 to prevent the push rod 21 and the front sleeve 15 from rotating. Therefore, the front tube sleeve 15 and the push rod 21 rotate synchronously.
[0005]
The push bar 21 is integrally provided on the tail end side of the decorative material support tray 17. 5 has the same structure as the push rod (the push rod 21 in FIG. 3) used in the stick-shaped decorative material feed container of the present invention, so see FIG. 3 as well. On the outer surface of the push bar 21, a group of protrusions 23 extending in the axial direction are provided in four rows so as to be distributed 90 degrees in the circumferential direction. The interval between the protrusions 23 adjacent to each other in the upper and lower sides of each row is a constant pitch. The protrusions 23 are arranged linearly in the axial direction, and at the same time, are arranged so as to draw a virtual spiral on the outer surface of the push bar 21. The protrusion 23 is screwed with a female screw 37 on the inner surface of the female screw part 35 of the female screw cylinder 41 ′. That is, the same spiral groove (with clearance) as the virtual spiral formed by the group of protrusions 23 is formed as the female screw 37 of the female screw part 35.
[0006]
As shown in FIG. 3 (90 ° rotation with FIG. 5), a bend stopper 53 having an outer protrusion 52 protruding outward from the outer peripheral surface of the same is provided at the tail end of the push bar 21. . The bend stopper 53 is formed in a tongue shape by a U-shaped slit 51 cut into the wall surface of the hollow push bar 21. That is, since the bend stopper 53 is a cantilever beam having the base (lower side) as a support portion, the bend stopper 53 is easily bent around the base. As described above, the upper portion of the bend stopper 53 is the outer protruding portion 52 that protrudes outward, and the contact surface 56 that is the upper end surface of the outer protruding portion 52 is the lower end of the female screw portion 35 of the female screw cylinder 41 ′. Abutting with the abutting surface 38, the feeding end of the push rod 21 is defined. When the push bar 21 is passed through the female screw 37, the bend stopper 53 bends inward so that it does not become an obstacle.
[0007]
The upper part of the female thread cylinder 41 ′ is the female thread part 35 as described above. A connection groove 86 is cut in a ring shape on the outer surface of the female thread cylinder 41 ′ below the female thread part 35. A ring-shaped connecting protrusion 85 projecting from the lower inner surface of the front sleeve 15 is rotatably engaged with the connecting groove 86, so that the front sleeve 15 and the female thread tube 41 'are freely rotatable. Connect to In addition, the process (caulking) of this connection protrusion 85 is performed after an assembly with internal thread cylinder 41 '. On the outer surface of the female screw cylinder below the connecting groove 86, there is provided a resistance projection 89 that provides resistance to the rotation of the female cylinder 41 ′ and the front sleeve 15 . Details of the resistance protrusion 89 will be described later. The lower outer peripheral portion (above the bend stopper 50) of the female screw cylinder 41 ′ below the resistance projection 89 is provided with a rotation preventing portion 99 (uneven fitting), and the female screw cylinder 41 ′ and the outer cylinder 90 are prevented from rotating. Is done.
[0008]
A bend stopper 50 having a structure similar to that of the bend stopper 53 at the tail end portion of the push rod 21 is provided at the tail end portion of the female screw cylinder 41 '. That is, a slit 47 is formed in a U-shape on the side wall of the female thread cylinder 41 ′, and a portion surrounded by the slit 47 is a bend stopper 50. The upper portion of the bend stopper 50 is an outer protrusion 49 protruding outward. The outer protrusion 49 abuts on a rear end portion 97 of an outer cylinder 90 described later to lock the female thread cylinder 41 and the outer cylinder 90 in the axial direction.
[0009]
The outer cylinder 90 is an assembly of a cap fitting member 93 and a hook member 95. The outer cylinder 90 is exclusively for decoration, and the container mechanism is achieved without the outer cylinder 90. The cap fitting member 93 is a thin pipe-shaped member made of metal (such as brass or aluminum). The hook member 95 is a bottomed cylindrical member made of metal. Both are fixed by knurling or adhesive.
[0010]
The outer surface of the upper end portion of the cap fitting member 93 is a cap fitting portion 18. An inner surface of a tail portion of a cap (not shown) is fitted to the outer surface of the portion 18 so that the cap is locked. Further, the lower end 97 of the cap fitting member 93 comes into contact with the upper surface of the bend stopper 50 at the tail portion of the female screw cylinder 41 ′. As a result, the female screw cylinder 41 and the outer cylinder 90 are locked in the axial direction. On the inner surface of the lower part of the cap fitting member 93 and the outer surface of the female screw cylinder 41 facing the cap fitting member 93, there are provided engagement vertical stripes, which serve as a detent portion 99. As a result, the female screw cylinder 41 and the outer cylinder 90 are locked in the rotational direction.
[0011]
When the cosmetic material is delivered using the stick-shaped cosmetic material delivery container of FIG. 5, the outer cylinder 90 and the front sleeve 15 are relatively rotated (for example, the front sleeve 15 is held and fixed with the left finger). Rotate the outer cylinder 90 with the finger of the right hand). Then, the front sleeve 15, the decorative material support plate 17, and the push bar 21 do not rotate, and the outer tube 90 and the female screw tube 41 ′ rotate. For this reason, the group of protrusions 23 that also act as male screws on the outer surface of the push bar 21 rises along the female screw 37 to be screwed, and the push bar 21 is extended (raised) in the axial direction.
[0012]
When the push rod 21 is raised, the bend stopper 53 at the tail end of the push rod 21 is also raised, and finally comes into contact with the contact surface 38 which is the lower end surface of the female thread portion 35. At this point, the push bar 21 cannot be fed out, and the push bar feed limit is delimited. When retracting the push rod 21, the front sleeve 15 and the outer tube 90 may be rotated in the opposite directions. Note that the pull-in end of the push bar 21 is determined by the bottom of the cosmetic material support tray 17 coming into contact with the upper end portion of the female screw cylinder 41 '.
[0013]
Next, the resistance protrusion 89 will be described.
A resistance projection 89 is provided on the lower outer surface of the female thread cylinder 41 'in a shape like a round head. In addition, this resistance protrusion is protrudingly provided on the bend piece 100 (after-mentioned). The resistance protrusions 89 are provided at the left and right of the female screw cylinder 41 'with a 180 ° distribution. The width between the tops of the left and right resistance projections 89 is made slightly wider than the diameter of the inner surface 87 of the front sleeve 15, and the tops of the resistance projections 89 interfere with the sleeve inner surface 87. This interference creates a rotational resistance between the front sleeve 15 and the female thread 41 '.
[0014]
FIG. 6 is a side view (detailed view from the side of FIG. 5) showing details of the portion of the resistance projection 89 of the female screw cylinder 41 ′. The resistance protrusion 89 is formed so as to rise on the bend piece 100 sandwiched between two parallel slits 101 cut in the axial direction on the side wall of the female thread cylinder 41 ′. As described above, since the resistance protrusion 89 interferes with the sleeve inner surface 87, the bend piece 100 is slightly bent inward. Therefore, the top of the resistance projection 89 is pressed against the sleeve inner surface 87 by the reaction force of the bend. Therefore, an appropriate rotational resistance associated with the pressing force can be obtained.
[0015]
In FIG. 6, it is the anti-blur projection 88 that protrudes roundly from the side surfaces of the left and right female cylinders 41 ′ of the bend piece 100. The dimension between the left and right anti-shake projections 88 is substantially the same as the inner diameter of the sleeve inner surface 87. The anti-shake projection 88 prevents the female screw cylinder 41 ′ from shaking within the front sleeve 15.
[0016]
[Problems to be solved by the invention]
The stick-shaped cosmetic material feeding container of the above-mentioned Japanese Patent Application No. 6-288617 does not require an O-ring for imparting sliding resistance and exhibits excellent characteristics as a whole. It turns out that there is room for improvement.
(1) The sliding frictional force tends to decrease with the passage of time.
FIG. 7 is a graph showing a long-term change over time of the rotational resistance torque of the container when the stick-shaped decorative material supply container is supplied. A conventional bar-shaped cosmetic material feeding container is shown as a lower comparative example. Although it was a large turning resistance torque at the time of completion, the turning resistance torque dropped significantly after being left for one or two weeks, and further gradually decreased even after 5 to 12 weeks. This is presumably because the bend piece creeps inward and the interference between the protrusions becomes weak, and the pressing force acting between the protrusion and the inner surface of the front sleeve and the frictional force resulting from it decrease. Such a tendency is not preferable for a bar-shaped cosmetic material supply container having a considerably long period from production to sales and a period of use.
[0017]
(2) Since the rotation resistance torque of the container was too high at the initial value, the rotation test could not be performed immediately after assembly. This is because there is a problem of (1) above, and the initial turning resistance torque had to be made extremely high. If the tube sleeve (metal sleeve) 15 is fitted, then the rotation test is performed, and then the connecting protrusion 85 is crimped, and then the rotation becomes loose after that, the assembled unit becomes defective. The loss is significant. On the other hand, if the rotation test was performed after a while after assembly, time management and the burden of inventory were serious.
[0018]
(3) Since the width of the head of the resistance protrusion is narrow, a step on the inner surface of the front sleeve may be picked up when the container is rotated, and a catching feeling (pulsation) may appear. This is a phenomenon that tends to occur in the case of the metal tip cylinder sleeve 15 having the anti-rotation groove 16 on the inner surface in the stick-shaped cosmetic material feeding container of FIG. This is because the inner surface 87 of the front sleeve where the resistance protrusion 89 slides should basically be a circumferential surface without irregularities, but the processing of the anti-rotation groove 16 and the surface treatment of the metal sleeve (alumite processing, etc.) This is because, due to the influence, fine stripes in the axial direction may exist on the same inner surface. If a sticking or pulsating sensation appears when the stick-shaped cosmetic material feeding container is rotated to feed or retract the stick-shaped cosmetic material (if a uniform and smooth rotational resistance feeling cannot be obtained), the stick-shaped cosmetic material feeding container However, it seems like a cheap low-end product, which is a fatal defect for cosmetics where a high-class image is extremely important.
[0019]
SUMMARY OF THE INVENTION An object of the present invention is to provide a sliding friction imparting mechanism that requires little change in sliding resistance with time and can obtain a stable and smooth operation. It is another object of the present invention to provide a stick-shaped decorative material feeding container having such a sliding friction imparting mechanism and having a sense of quality.
[0020]
[Means for Solving the Problems]
In order to solve the above problems, a sliding friction applying mechanism according to the present invention includes a first member having a bend piece and a second member having a sliding surface on which the bend piece slides by being pressed by its elasticity. A sliding friction applying mechanism, wherein the bend piece is a double-sided bending beam and receives a pressing force from the convex side to the concave side of the bending beam.
[0021]
When a load is applied to the curved beam of both ends from the convex side to the concave side, the bending stress acting on the cross section of the beam is weaker than the case where a lateral load is applied to the straight beam, and the compressive stress is superior. To do. A typical example is a so-called arch, in which only compressive stress works in the member. Therefore, a structure such as a masonry arch bridge is possible. In the case of a resin material or the like, due to its molecular structure, creep deformation under compressive stress is considered to be several steps less than creep deformation under tensile stress. Therefore, by making the bend piece an arch type so that tensile stress is not applied to the bend piece as much as possible, creep deformation of the bend piece is prevented.
[0022]
The bar-shaped decorative material feeding container of the present invention includes a chuck holding a tail portion of the bar-shaped decorative material, a push rod having a male screw, a female screw cylinder having a female screw screwed with a male screw of the push rod, and a female screw tube being rotatably connected. And a front sleeve having a non- rotating groove that rotates synchronously with the push rod, and the push rod is advanced and retracted by relatively rotating the female screw tube and the front sleeve , thereby feeding and retracting the rod-shaped decorative material. A stick-shaped cosmetic material feeding container to be used;
In the fitting sliding portion in which the female cylinder and the front sleeve are connected, a bend piece is formed as an arcuate piece between a pair of opposed slits cut so as to extend in the circumferential direction of the cylinder located inside. The bend piece is formed and is pressed against a cylinder located outside by its elasticity, and friction is imparted to the rotation of both cylinders.
[0023]
Also in this stick-shaped decorative material feeding container, the arc-shaped piece of the inner cylinder is an arc-shaped curved beam. Therefore, the stress caused by the pressing force of the bend piece is superior in the pressing force, so that creep deformation is suppressed, and fluctuations in the pressing force and frictional force are reduced. Furthermore, if the bend piece is an arc-shaped piece (perpendicular to the axial direction, transverse direction), the length can be increased. Therefore, a laterally extending protrusion extending in the circumferential direction is formed on the bend piece, and the outer surface of the protrusion is formed. Can have substantially the same curvature as the sliding surface, and the projection can be pressed against the sliding surface. Further, the length of the protrusion can be freely selected to some extent. In this case, even if there is a step or unevenness on the mating sliding surface, there is a protrusion over the step on the sliding surface, so that it is possible to eliminate the feeling of catching at the time of rotation. In addition, the purpose of the rotation resistance in the stick-shaped decorative material feeding container of the present invention is to prevent the cup feeling when the lead angle of the screw is large in addition to improving the operational feeling described above. Also good.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, it demonstrates more concretely, referring drawings.
FIG. 1 is a cross-sectional view showing a structure of a stick-shaped decorative material feeding container according to an embodiment of the present invention.
FIG. 2 is a view showing a front sleeve of the stick-shaped decorative material feeding container of FIG. (A) is a partial sectional side view, (B) is a BB sectional view of (A).
FIG. 3 is a side view showing a push rod with a plate of the stick-shaped decorative material feeding container of FIG. 1.
FIG. 4 is a view showing a female screw cylinder of the stick-shaped decorative material feeding container of FIG. 1. (A) is a side view, (B) is BB sectional drawing of (A).
In the figure, the portions denoted by the same reference numerals as those of the conventional stick-shaped decorative material feeding container of FIG. 5 are basically the same in structure and operation as in the prior art, and the description thereof is omitted.
[0025]
1-4 is the same as the conventional bar-shaped cosmetic material feeding container of FIGS. 5 and 6 in the basic feeding mechanism. The differences are as follows.
First, the bend piece is a horizontal type. As shown in FIG. 4A, two slits 203 extending in the vertical direction (lateral direction) with respect to the axial direction are cut in the side wall of the female screw cylinder 41 in parallel up and down. A side wall portion between the two slits 203 </ b> A and B is an arcuate horizontally long bend piece 201. The cross-sectional shape perpendicular to the axis of the bend piece 201 is shown in FIG. The bend piece 201 is basically the side wall itself of the female screw cylinder 41, but the dent 205 dug into the outer surface of the female screw cylinder 41 becomes a stealer, and the thickness is about half that of the side wall. The rigidity of the bend piece 201 can be adjusted by adjusting the depth or length of the recess 205. Since the overall shape of the bend piece 201 is a part of the cylindrical side wall, it is an arc piece.
[0026]
On the outer surface of the central portion of the bend piece 201, a horizontally long resistance protrusion 202 extending in the circumferential direction is projected. Two bend pieces 201 and two protrusions 202 are provided so as to be opposed to each other by 180 ° in axial symmetry. These protrusions 202 rotate and slide on the lower inner surface 87 of the front sleeve 15. The dimension between the tops of the two protrusions is slightly larger than the diameter of the inner surface 87 of the front tube sleeve. When the female tube 41 is assembled in the front tube sleeve 15, the bend piece 201 bends inward. The pressing force accompanying the elasticity acts between the projection 202 outer surface 207 and the front sleeve inner surface 87. This pressing force is similar to the lateral load applied to the arch as described above, and the bending stress in the bend piece 201 is superior to the compressive stress.
[0027]
The curvature of the outer surface 207 of the resistance protrusion 202 in FIG. 4B is substantially the same as the curvature of the inner surface 87 of the front sleeve. In addition, when viewed in a right angle direction (axial direction) in FIG. 4B, a medium-high R is given to the outer surface, and the resistance due to the elastic force is made uniform by making the contact between the two as a line contact.
[0028]
The improvement result of the long-time change of the rotational resistance torque in the stick-shaped cosmetic material feeding container of the present embodiment will be described based on the measurement result. FIG. 7 is a graph showing measured values of the change in the rotational resistance torque. The embodiment in the figure is a stick-shaped decorative material feeding container having a horizontally long bend piece (curved beam) according to an embodiment of the present invention. As described above, the comparative example is a stick-shaped decorative material feeding container having a vertically long bend piece (straight beam). In the curve of the example, although the initial turning resistance torque at the elapsed time 0 is lower than that of the comparative example, the subsequent turning resistance torque decrease is much smaller than that of the comparative example. The dynamic resistance torque is higher in the embodiment. In addition, after 5 weeks, the rotational resistance torque hardly decreases and is extremely stable. On the other hand, in the comparative example, the rotational resistance torque gradually decreases after 5 weeks, and the torque value is finally stabilized at about 1/3 to 1/5 of the initial torque. However, the variation in value is large. Thus, the stick-shaped decorative material feeding container of this embodiment is excellent in the stability of the rotational resistance torque.
[0029]
A second point of difference between the stick-shaped decorative material feeding container of FIG. 1 and the stick-shaped decorative material paying container of FIG. 5 is that the outer cylinder 90 is an integral part of resin molding. However, it is arbitrary and not a feature of the present invention. Also, the sleeve, the push rod with a dish, and the female thread cylinder form a single unit, and the assembly is the same by simply inserting it into the container body.
[0030]
In addition, since the spiral of the push rod with a plate in the prior art is usually formed by a split mold by a molding machine, the feeding stroke cannot be freely selected. However, the present invention does not use a conventional spiral with a split mold, and has a form in which a protrusion is provided on the outer surface of a push rod with a plate and the protrusion is extended by a spiral cylinder. A larger stroke pitch is now possible. In the conventional technique, when there is no feeling of feeding weight, there is also a phenomenon that the cup falls down, that is, the cosmetic material on the upper stick-shaped decorative material support part of the push rod with the dish is naturally pushed down from above. . To that end, it has been necessary to use an elastic material that can withstand a long-term use as an elastic material with a stable feeding weight feeling. The present invention can meet such a demand.
[0030]
【The invention's effect】
(1) Since a separate friction member such as an O-ring is not used, the number of assembling steps is reduced, leading to an improvement in productivity.
(2) Since the rotation resistance member is provided perpendicular to the axial direction, the length of the bend piece can be made longer than that of the vertical slit. In addition, the following effects (i) to (d) occurred in relation to it.
A: The metal sleeve can be made shorter than the conventional one. Since it is difficult to produce a sleeve provided with a rotation stopper protrusion on the metal sleeve, the metal sleeve can be easily produced by shortening the length.
B: Because the bend piece length (between strips) is long, it is possible to manufacture protrusions with an outer diameter that is almost the same as the sleeve inner diameter, and the protrusion does not pick up scratches or the like due to anodizing of the sleeve inner diameter. . Therefore, a pleasant sliding feeling can be obtained.
C: Since the protrusions are in the same direction as the rotation direction, the deformation of the protrusions is difficult to occur, and deformation between the belts is also difficult to occur.
D: Since the thickness between the strips can be made thick or thin freely, and the length of the bend piece can be adjusted, the elastic force can be determined by a flexible numerical value. For example, even when there is a manufacturing dimensional error (plus or minus 0.02 to 0.03 mm for each) in the combination of a metal sleeve and a resin female screw cylinder, stable rotation is achieved despite the error. It has extremely important significance in the industry that the dynamic friction force can be maintained.
(3) Stable feeding and lowering weight can be maintained even at the pitch and lead where the inner plate causes cup-down.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a structure of a stick-shaped decorative material feeding container according to an embodiment of the present invention.
FIG. 2 is a view showing a front sleeve of the stick-shaped cosmetic material supply container of FIG. 1; (A) is a partial sectional side view, (B) is a BB sectional view of (A).
FIG. 3 is a cross-sectional view showing a push rod with a plate of the stick-shaped decorative material feeding container of FIG. 1;
4 is a view showing a female screw cylinder of the stick-shaped decorative material feeding container of FIG. 1; FIG. (A) is a side view, (B) is BB sectional drawing of (A).
FIG. 5 is a cross-sectional view showing the internal structure of a stick-shaped cosmetic material feeding container (lipstick container) proposed by the inventors of the present application in Japanese Patent Application No. 6-288617.
6 is a side view (detailed view from the side of FIG. 5) showing details of a portion of the resistance protrusion 89 of the female screw cylinder 41 ′. FIG.
FIG. 7 is a graph showing a time-series change of the rotation resistance torque of the container when the stick-shaped decorative material supply container is extended over a long period of time.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bar-shaped cosmetic material delivery container 2 Cap 11 Tip opening 13 Cosmetic material 15 Front tube sleeve 16 Non-rotating groove 17 Chuck (dish) 18 Cap fitting part 20 Non-rotating protrusion 21 Push bar 23 Protrusion 35 Female thread part 37 Female thread 38 Contact surface 41 Female thread 45 Through-hole 47 Slit 49 Outer protrusion 50 Bend stopper 51 Slit 52 Outer protrusion 53 Bend stopper 56 Abutment surface 85 Connection protrusion 86 Connection groove 87 Sleeve inner surface 88 Anti-shake protrusion 89 Resistance protrusion 90 Outer cylinder 93 Cap fit Joint member 95 Hakama member 97 Cap fitting lower end 99 Non-rotating portion 100 Bend piece 101 Slit 201 Horizontally long bend piece 202 Resistance projection 203 Slit 205 Recess 207 Outer surface 211 Step

Claims (5)

A push rod having a chuck and a male screw for holding the tail portion of the rod-shaped decorative material, a female screw cylinder having a female screw threadedly engaged with the male screw of the push rod, and a rotation- preventing groove that is rotatably connected to the female screw tube and rotates synchronously with the push rod. and a leading tube sleeve having, to advance and retract the push rod by relatively rotating the said internal thread cylinder and the leading tube sleeve, a stick type cosmetic material feeding container of the protruding and retracted the stick type cosmetic material with;
In the fitting sliding portion in which the female cylinder and the front sleeve are connected, a bend piece is formed as an arcuate piece between a pair of opposed slits cut so as to extend in the circumferential direction of the cylinder located inside. A stick-shaped cosmetic material supply container, wherein the bent piece is pressed against a cylinder located outside by the elasticity of the bend piece and friction is applied to the rotation of both cylinders. The bend piece is formed with a laterally long protrusion extending in the circumferential direction, and the outer surface of the protrusion has substantially the same curvature as the sliding surface on which the bend piece is pressed by its elasticity and slides. The stick-shaped decorative material feeding container according to claim 1, which is pressed against the sliding surface. The stick-shaped cosmetic material feeding container according to claim 1 or 2, wherein the front sleeve is made of metal, and a synchronous engagement groove with a chuck is formed on an inner diameter thereof. The stick-shaped cosmetic material feeding container according to claim 3, wherein the front sleeve is made of aluminum and anodized. The stick-shaped cosmetic material feeding container according to any one of claims 1 to 4, wherein the sliding friction applying mechanism by the bend piece has a function of preventing the chuck from naturally descending (cup down).

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