JP7488434B1 - Stirring device and free spring part used therein - Google Patents

Abstract

[Problem] To provide an agitator that can reduce the powderiness of beverages made by mixing powdered food with water. [Solution] The agitator 1 stores protein powder and water and produces protein liquid by shaking, and has a storage section 10 that extends vertically and stores the powder and water, an upper opening and closing section 11 provided at the top of the storage section 10 for putting in the powder and water and discharging the protein liquid, and a free spring section 13 stored inside the storage section 10, the free spring section 13 includes a coil spring 20 with a constant winding diameter, a dense pitch in the center and a sparse pitch on both sides of the center, and impactors 21, 22 attached to both ends of the coil spring 20, and can slide vertically inside the storage section 10. [Selected Figure] Figure 1

Description

The present invention relates to a mixing device that mixes powdered food and water, and a free spring used in the device.

A conventional technique of this type is described in Patent Document 1. Patent Document 1 discloses a whisk that has a storage section with an inner space extending vertically and a grip-shaped exterior, an opening/closing section, and a coil spring with a constant winding diameter that is freely movable vertically inside the storage section, stores a liquid mixture of liquid (e.g., water) and a substance to be dispersed in it (e.g., oil, powder, granules, etc.) in the storage section, disperses the substance to be dispersed in the liquid by shaking, and allows the user to whisk by shaking the whisk up and down or left and right with their hands.

Patent Publication No. 6964923

People who want to increase muscle mass and strength are recommended to drink protein within 30 minutes after exercise, which is known as the golden time. For this reason, an increasing number of people are carrying water bottles filled with protein so that they can drink protein after exercise. In recent years, therefore, there has been a demand for a stirring device that can reduce powdery texture and create a protein liquid that is easy to swallow, making protein easier to drink.

The present invention aims to solve these problems and provide a stirring device and a free spring for use therewith that can reduce the powdery texture of beverages made by mixing powdered food with water.

To achieve the above objective, the present invention has the following configuration.

(1) A stirring device that contains a substance to be dispersed (e.g., protein powder) and a liquid (e.g., water) and generates a liquid (e.g., a protein liquid) by dispersing the substance to be dispersed in the liquid by shaking the device,
A vertically extending storage section (e.g., storage section 10) for storing the object to be dispersed and the liquid;
An upper opening/closing part (e.g., an upper opening/closing part 11) that is provided at the upper part of the storage part and opens and closes an opening of the storage part so as to put in the object to be dispersed and the liquid and to discharge the liquid material;
A free spring portion (e.g., a free spring portion 13) that is accommodated inside the accommodation portion,
The free spring portion is
a coil spring (e.g., coil spring 20) that is stored inside the storage section, has a constant winding diameter, a dense pitch in a central portion, and a sparse pitch on both sides of the central portion;
A stirring device characterized in that the height of the coil spring is shorter than the height of the storage section, the outer diameter of the coil spring is shorter than the inner diameter of the storage section, and the coil spring can slide vertically inside the storage section when the storage section is swung vertically.

According to (1), the user can put the material to be dispersed and the liquid into the stirring device and shake it by hand to cause the coil spring to vibrate and swing, stirring the material to be dispersed in the liquid, and can immediately remove it from the storage section for use. By providing a pitch variation in the coil spring, it is easy to maintain the vibration and swing using the coil spring as a weight. Furthermore, the dense pitch part of the coil spring stirs up the liquid, resulting in a shearing effect. In particular, by providing the dense pitch part in the center, when the stirring device 1 is swung up and down to slide the coil spring and the end of the coil spring hits the bottom surface of the storage section or the lower surface of the upper opening and closing section, the sparse part of the coil spring on the side that hits the bottom surface of the storage section or the lower surface of the upper opening and closing section from the center expands and contracts more, and the expansion and contraction width is smaller than that of the sparse part on the opposite side. This makes it possible to place many turns of the coil spring at the top and bottom of the storage section, which makes it possible to break down powdered materials that tend to settle in the lower part of the storage section, or materials that move to the top of the storage section and remain near the bottom of the upper opening/closing section. Furthermore, each time the storage section is shook, the coil spring can collide twice with the bottom of the storage section and the bottom of the upper opening/closing section, and by increasing the number of collisions, the coil spring can be vibrated finely, breaking down powdered foods into small pieces. This makes it possible to reduce the powdery texture of powdered foods and produce a liquid that is easy to swallow.

(2) In (1),
The free spring portion is
a first impact body (e.g., a first impact body 21) attached to an upper end of the coil spring;
A second impact body (e.g., a second impact body 22) attached to a lower end of the coil spring,
The stirring device according to claim 1, wherein, when the storage unit is shaken, the second impact body collides with a bottom surface of the storage unit, and the first impact body collides with a lower surface of the upper opening/closing portion.

(2) The ends of the coil spring do not come into direct contact with the bottom surface of the storage section or the underside of the upper opening/closing section, preventing damage to the bottom surface of the storage section or the underside of the upper opening/closing section.

(3) In (2),
the first impact body and the second impact body have the same shape,
The first impact body and the second impact body are
A cylindrical portion (e.g., cylindrical portion 210, cylindrical portion 220) into which an end of the coil spring can be inserted;
A donut-shaped flat plate portion (e.g., inner flat plate portion 212, 222) extending from an upper end of the cylindrical portion toward a central axis of the cylindrical portion;
A sector-shaped recess (e.g., recess 21a, recess 22a) is formed at a corner between the cylindrical portion and the flat plate portion,
The dent is,
A wall portion (e.g., wall portion 215, wall portion 225) extending vertically along the central axis from a part of a central hole formed in the central portion of the flat plate portion;
A horizontal surface portion (e.g., horizontal surface portion 216, horizontal surface portion 226) extending from an end of the wall portion to the cylindrical portion;
A pair of side surfaces (e.g., side surfaces 217, 217 and side surfaces 227, 227) extending from both circumferential sides of the wall surface portion along both circumferential sides of the horizontal surface portion;
and notches (e.g., notches 218, 218, notches 228, 228) formed by cutting out the cylindrical portion and the base portions of the pair of side portions where the side portions meet the horizontal surface portion,
The stirring device according to claim 1, wherein the notch has a width that allows an end of the coil spring to be inserted therethrough.

According to (3), it is possible to attach an impact body to the end of the coil spring by inserting the end of the coil spring into the notch and sandwiching the horizontal surface between the springs or by engaging two adjacent windings on the upper and lower surfaces of the notch.

(4) The stirring device according to (3), characterized in that a plurality of protrusions (e.g., small protrusions 210a, 210a, small protrusions 220a, 220a) protruding downward are formed on the lower end surface of the cylindrical portion.

According to (4), when the impact body collides with the bottom surface of the storage section, multiple protrusions (e.g., small protrusions 220a, 220a) collide with the impact body, so the impact area of the impact body can be made smaller. This makes it possible to reduce the impact sound.

(5) The stirring device according to (3), characterized in that a plurality of bulges (e.g., bulges 222a, 222a) bulging toward the central axis of the cylindrical portion are formed on the inner end surface of the flat portion.

According to (5), by forming a bulge on the inner end surface of the flat plate, the area of the underside of the inner flat plate can be increased, making it possible to apply water pressure to the bottom surface of the storage section and the underside of the upper opening/closing section more efficiently, and making it possible to disperse sediments near the bottom surface of the storage section and deposits near the underside of the upper opening/closing section.

(6) In any one of (3) to (5), a mixing device is characterized in that a plurality of holes (e.g., long hole 214, long hole 224) are formed in the flat surface of the flat plate portion.

According to (6), since a plurality of holes are formed in the flat surface of the flat portion, when the impact body moves up and down, sediment near the bottom surface of the storage section and deposits near the underside of the upper opening/closing section can easily pass through the holes and move to the lower portion of the coil spring.
(7) A free spring that is inserted into a container having a vertically extending storage section for storing a substance to be dispersed and a liquid, and an upper opening/closing section that is provided at the top of the storage section and opens and closes an opening of the storage section, and that disperses the substance to be dispersed in the liquid by shaking the container,
A coil spring having a constant winding diameter, a dense pitch in a center portion, and a sparse pitch on both sides of the center portion;
A first impact body attached to an upper end of the coil spring;
A free spring comprising: a second impact body attached to a lower end of the coil spring.

According to (7), by inserting the free spring of the present invention into a container that contains the object to be dispersed and liquid and shaking it, the same effect as (1) can be achieved.

The present invention makes it possible to provide a mixing device that can reduce the powdery texture of beverages made by mixing powdered food with water.

1 is a diagram showing the appearance of an agitation device 1 according to an embodiment of the present invention; FIG. 2 is an exploded perspective view showing components of the stirring device 1 according to the first embodiment of the present invention. FIG. 2 is a perspective view showing the appearance of a first impactor 21 (second impactor 22). FIG. 13 is a perspective view showing the appearance of a modified first impactor 21 (second impactor 22). 13 is a view showing a modified example of the first impact body 21 (second impact body 22) as viewed from below. FIG. FIG. 2 is a diagram for explaining in detail the pitch density of the coil spring and the wire diameter that constitutes the coil spring. FIG. 2 is a diagram for explaining in detail the pitch density of the coil spring and the wire diameter that constitutes the coil spring. FIG. 2 is a diagram for explaining in detail the pitch density of the coil spring and the wire diameter that constitutes the coil spring. This is an explanatory diagram showing a comparison of the weight of protein powder adhering to the sieve mesh in a sieve see-through test. FIG. 1 is an explanatory diagram showing a comparison of powder sieving times in a sieving test. This is an explanatory diagram showing the appearance of a stirring device that serves as a comparative example for comparing the weight of protein powder adhering to the sieve mesh and the powder sieving time. FIG. 13 is an explanatory diagram showing the powder sieving time in a sieving test when the free spring portion 13 is not used.

Below, an embodiment of the present invention will be described with reference to the drawings. Items with the same reference numerals in the drawings have similar configurations and functions.

Figure 1 is a side view showing the appearance of an agitation device 1 according to one embodiment of the present invention. Figure 2 is an exploded perspective view showing the components of an agitation device 1 according to one embodiment of the present invention.

[composition]
The stirring device 1 includes a storage section 10, an upper opening/closing section 11, a cap section 12, and a free spring section 13. The stirring device 1 puts an object to be dispersed (e.g., protein powder) and a liquid (e.g., water) into the storage section 10, inserts the free spring section 13, attaches the upper opening/closing section 11 with the cap section 12 attached to the storage section 10 to close and seal the opening of the storage section 10, and shakes the storage section 10 up and down and left and right to stir, thereby generating a liquid body in which the object to be dispersed in the liquid is diffused. The user can remove the cap section 12 to take out the liquid body. In the following description, an example will be described in which protein powder is put into the storage section 10 as the object to be dispersed and water is put into the storage section 10 as the liquid, and protein liquid is generated as the liquid body by stirring.

The storage unit 10 is a cylindrical container with a bottom that can store protein liquid. The bottom of the storage unit 10 is formed into a disk shape with an outer diameter of about 70 mm, and the side of the storage unit 10 extends from the bottom while gradually reducing in diameter upward. Therefore, the storage unit 10 is a conical container that is close to a cylinder with a missing top, and has a gentle narrowing at the upper and lower parts of the center. As a result, the center is thicker, making it easier for the user to hold the storage unit 10. For the convenience of the following explanation, the direction along the central axis of the storage unit 10 will be referred to as the up-down direction, the bottom side of the storage unit 10 will be referred to as the lower side, and the opening side will be referred to as the upper side.

The storage section 10 is made of a transparent or semi-transparent material such as polyethylene or polypropylene that is also flexible, and allows the contents to be visually checked for separation, precipitation, dispersion, and other conditions. The protein liquid inside can be pushed out by pressing down on the storage section 10 with the hand holding it. The material of the storage section 10 may be colored or lightly colored. The storage section 10 may also be made of a transparent material with a design drawn on it.

The size of the storage unit 10 depicted in FIG. 1 can be, for example, 170 mm in height and 60 mm in diameter at the center when held by a person.
A diameter of 50 to 70 mm, a height of 150 to 170 mm, and a capacity of about 280 to 400 mm are suitable for a person to hold and swing.
1 is drawn to have a shape close to a cylinder, but other shapes are also possible. In order to increase the storage capacity, the center part may be made slightly wider, and in order to prevent the agitator 1 from slipping out of the hand when it is shook, the center part may be made to have an easy-to-grip shape, for example, a shape that can be easily gripped by placing the fingers thereon.

The upper end of the storage section 10 has a flat plate portion 10a that extends inward in a doughnut shape, and a cylindrical portion 10b that extends upward from the flat plate portion 10a. The flat plate portion 10a extends a length approximately equal to the thickness of the lower cylindrical portion 11a of the upper opening/closing section 11, which will be described later. The cylindrical portion 10b has a screw thread on its side. In other words, an opening is formed at the upper end of the storage section 10 by the cylindrical portion 10b.

The upper opening/closing part 11 is attached to the upper end of the storage part 10, and by narrowing the opening at the upper end of the storage part 10, it makes it easier for the user to drink the liquid stored inside the storage part 10. The upper opening/closing part 11 is composed of a lower cylindrical part 11a formed in a cylindrical shape with an outer diameter approximately the same as the outer diameter of the flat part 10a of the storage part 10, a flat part 11b extending inward from the upper end of the lower cylindrical part 11a in a doughnut shape, and an upper cylindrical part 11c extending upward from the edge of the hole in the center of the flat part 11b. The central axis of the lower cylindrical part 11a and the central axis of the upper cylindrical part 11c are aligned. The inner side surface of the lower cylindrical part 11a is formed with a screw groove that screws into the screw thread formed at the upper end of the storage part 10. The outer side surface of the upper cylindrical part 11c is formed with a screw thread that screws into the cap part 12.

The cap portion 12 is a cylinder closed at the top, and has a threaded groove on the inner side of the cylinder that screws into the threads formed on the outer side of the upper cylindrical portion 11c.

After storing the protein powder and water in the storage section 10, the upper opening/closing section 11 to which the cap section 12 is attached is screwed onto the upper part of the storage section 10, thereby maintaining airtightness so that water does not spill from the storage section 10 to the outside. When the upper opening/closing section 11 is screwed onto the storage section 10, the outer side of the storage section 10 and the outer side of the upper opening/closing section 11 become roughly flush with each other, and the lower surface of the lower cylindrical section 11a abuts against the flat plate section 10a. In this embodiment, the airtightness of the storage section 10 is maintained by screwing the upper opening/closing section 11 onto the storage section 10, but other opening/closing means such as a fitting type can be used as long as the airtightness can be maintained so that the protein liquid does not spill even if the storage section 10 is shaken by hand with the upper opening/closing section 11 fastened to the storage section 10.

The free spring section 13 includes a coil spring 20, a first impact body 21 attached to one end of the coil spring 20, and a second impact body 22 attached to the other end of the coil spring 20.

The free spring section 13 is disposed inside the storage section 10 to which the upper opening/closing section 11 is attached. The coil spring 20 is inserted into the storage section 10 from the second impact body 22 side, and then the first impact body 21 is inserted, so that the second impact body 22 abuts against the bottom surface of the storage section 10 and the first impact body 21 is spaced apart from the bottom surface of the upper opening/closing section 11, and the coil spring 20 is stored inside the storage section 10.

The design of the coil spring 20 (the pitch and the wire diameter of the coil spring) will be described later with reference to Figures 6 to 8. The coil spring 20 can slide vertically and horizontally inside the storage unit 10, and can freely vibrate and swing when the user shakes the storage unit 10 up and down and left and right. The material of the coil spring 20 can be, for example, iron (steel), stainless steel, titanium, titanium alloy, aluminum, plastic, etc. The wire that makes up the coil spring 20 may have various surfaces with irregularities.

The coil spring 20 is a coil spring with a constant winding diameter. The winding diameter is smaller than the horizontal size of the inside of the storage section 10, and is designed so that when a user holds the storage section 10 in their hand and shakes it, the coil spring 20 slides up and down and sideways and hits the inner surface of the storage section 10 and the underside of the upper opening and closing section 11, creating a spatial space within the storage section 10 that allows for movement including vibration and rocking by the coil spring 20. Here, vibration refers to the movement of the coil spring 20 in the direction of its central axis, and rocking refers to the rocking movement in a direction perpendicular to the direction of the central axis of the coil spring 20.

The coil spring 20 has about 7 or 8 turns in the center, which is tightly wound so that adjacent coils abut against each other in the normal state, and the multiple turns on both sides of this center have some space between adjacent coils in the normal state. The length of the coil spring 20 is preferably 50 to 70 percent of the inner height of the storage section 10. If it is too short, the stirring efficiency of the entire liquid will be reduced. If it is too long, the freedom of movement, including vibration and swinging, will be reduced.

The coil spring 20 swings and vibrates, exerting a shearing effect on the protein powder. In addition, if the surface of the coil spring 20 has various faces and is uneven, the surface shape of the coil spring 20 also exerts a shearing effect on the protein powder. As a result, the protein powder is made finer and more uniform, facilitating dispersion in water.

Figure 3 is a perspective view showing the appearance of the first impact body 21, where Figure 3(a) is a view of the first impact body 21 viewed from diagonally above, and Figure 3(b) is a view of the first impact body 21 viewed from diagonally below.

The first impact body 21 has a cylindrical portion 210 and a doughnut-shaped inner flat plate portion 212 that extends radially inward from the upper end of the cylindrical portion 210, and is made of the same material as the storage portion 10.

The outer diameter of the cylindrical portion 210 is set to be shorter than the inner diameter of the opening of the storage portion 10 and longer than the inner diameter of the upper cylindrical portion 11c. That is, the outer diameter of the cylindrical portion 210 is within the range of the flat plate portion 11b. Furthermore, the outer diameter of the cylindrical portion 210 is set to be shorter than the inner diameter of the narrowest part of the storage portion 10. Also, the inner diameter of the cylindrical portion 210 is set to be approximately the same as the outer diameter of the coil spring 20. Specifically, the outer diameter of the coil spring 20 is approximately 36 mm, and the outer diameter of the cylindrical portion 210 is approximately 38 mm. Therefore, the coil spring 20 and the first impact body 21 can be stored inside the storage portion 10.

A hole 213 is formed in the center of the inner flat plate portion 212, and arc-shaped long holes 214 are formed in multiple locations on the outer periphery of the inner flat plate portion 212. The inner diameter of the hole 213 is set to be shorter than the outer diameter of the coil spring 20. Seven long holes 214 are formed at equal intervals.

A sector-shaped recess 21a is formed at a part of the corner formed by the cylindrical portion 210 and the inner flat plate portion 212. This recess 21a is formed by cutting out a part of the corner formed by the cylindrical portion 210 and the inner flat plate portion 212 in a sector shape, and this cut-out part is covered by the wall portion 215, the horizontal surface portion 216, and the side surfaces 217, 217. That is, the wall portion 215 extends vertically downward from the edge of the hole portion 213. Also, the horizontal surface portion 216 extends from the lower end of the wall portion 215 toward the lower end of the cylindrical portion 210 at the cut-out part. Furthermore, the side surfaces 217, 217 extend from both circumferential sides of the wall portion 215 along both circumferential sides of the horizontal surface portion 216. The inner flat plate portion 212 and the wall portion 215 are perpendicular, and the upper surface of the inner flat plate portion 212 and the upper surface of the wall portion 215 are parallel.

Notches 218, 218 extending along the circumferential direction of the cylindrical portion 210 are formed in the base of the side portions 217, 217 with the horizontal surface portion 216 and in a part of the cylindrical portion 210. The lower surface of the notch 218 is flush with the upper surface of the horizontal surface portion 216. According to this embodiment, the angle of the notch end of the notch 218, 218 with respect to the central axis of the cylindrical portion 210 is set to about 89 degrees. The portion of the notch 218 formed in the wall surface portion 215 has the upper and lower surfaces of the notch 218, 218 slightly inclined so that the notch width narrows toward the wall surface portion 215. The notch width of the notches 218, 218 is set to a width that allows two revolutions of the coil spring 20 to be inserted. The upper surface of the notch 218 is flush with the lower surface of the inner flat plate portion 212.

In this embodiment, the first impact body 21 has a shape that is line-symmetrical with respect to an imaginary plane that includes the central axis of the cylindrical portion 210 and the center of the horizontal surface portion 216.

When attaching the first impact body 21 to one end of the coil spring 20, first, the inner flat plate portion 212 is opposed to one end of the coil spring 20, and one end of the coil spring 20 is opposed to one notch 218 of the first impact body 21. Then, the first impact body 21 is rotated to insert one end of the coil spring 20 into one notch 218, move it along the inner surface of the cylindrical portion 210, insert it into the other notch 218, and move it along the inner surface of the cylindrical portion 210. In this way, about 2.5 revolutions of one end of the coil spring 20 are inserted into the first impact body 21, and a part of the one end of the coil spring 20 is positioned above the inner flat plate portion 212 and the other part is positioned below the inner flat plate portion 212, so that the first impact body 21 is attached to one end of the coil spring 20. In addition, when one end of the coil spring 20 is inserted into the first collision body 21 for at least one turn, the tip of one end of the coil spring 20 may be placed on the upper surface of the horizontal surface portion 216 without being inserted into the notch 218 from the second turn onwards. Furthermore, when attaching the first collision body 21 to a coil spring 20 whose end is not densely wound (for example, see FIG. 6(c)), the first turn is inserted into the notches 218, 218, the second turn is inserted into at least one of the notches 218, and the coil spring 20 may or may not be inserted into the other notch 218, and may even be placed on the upper surface of the horizontal surface portion 216. As a result, the coil spring 20 abuts against the upper and lower surfaces of one of the notches 218 in a slightly compressed state, so that the coil spring 20 engages with the notch 218, and the first collision body 21 is attached to one end of the coil spring 20.

The second impact body 22 has a recess 22a, a cylindrical portion 220, a small protrusion 220a, an inner flat plate portion 222, a bulge portion 222a, a hole portion 223, a long hole 224, a wall surface portion 225, a horizontal surface portion 226, a side surface portion 227, and a notch 228, which correspond to the recess 21a, the cylindrical portion 210, the small protrusion 210a, the inner flat plate portion 212, the bulge portion 212a, the hole portion 213, the long hole 214, the wall surface portion 215, the horizontal surface portion 216, the side surface portion 217, and the notch 218 of the first impact body 21. Since the first impact body 21 and the second impact body 22 have the same shape, a detailed description of the configuration of the second impact body 22 will be omitted.

The second impact body 22 is attached to the other end of the coil spring 20. The method of attaching the second impact body 22 to the coil spring 20 is the same as the method of attaching the first impact body 21 to one end of the coil spring 20, so a detailed explanation will be omitted.

The free spring section 13 is formed by attaching the first impact body 21 to one end of the coil spring 20 and the second impact body 22 to the other end. According to this embodiment, the natural length of the coil spring 20 is about 105 to 110 mm, and the heights of the first impact body 21 and the second impact body 22 are about 10 to 13 mm. Therefore, the length of the free spring section 13 is about 120 mm. By inserting this free spring section 13 into the storage section 10 from the second impact body 22 side, as shown in FIG. 1, the second impact body 22 abuts against the bottom surface of the storage section 10. Here, since the height of the storage section 10 is about 170 mm, when the upper opening/closing section 11 is attached to the storage section 10, the lower surface of the flat plate section 11b of the upper opening/closing section 11 and the upper surface of the first impact body 21 are spaced apart by about 50 mm. Therefore, by shaking the storage unit 10 up and down, the free spring portion 13 slides up and down inside the storage unit 10, the second impact body 22 collides with the bottom surface of the storage unit 10, and the first impact body 21 collides with the underside of the flat plate portion 11b of the upper opening and closing portion. Furthermore, when the free spring portion 13 is located in the center of the bottom surface of the storage unit 10, there is a distance of about 6 to 16 mm between the free spring portion 13 and the inner surface of the storage unit 10. Therefore, by shaking the storage unit 10 up and down, the free spring portion 13 can slide sideways inside the storage unit 10.

Figure 4 is a perspective view showing the appearance of a modified first impact body 21, where Figure 4(a) is a view of the modified first impact body 21 viewed from diagonally above, and Figure 4(b) is a view of the modified first impact body 21 viewed from diagonally below. Figure 5 is a view of the first impact body 21 in Figure 4(b) viewed from below.

The modified first impactor 21 shown in FIG. 4 is obtained by further forming a plurality of bulges 212a and a plurality of small projections 210a on the first impactor 21 shown in FIG.
The bulging portion 212a bulges toward the central axis of the cylindrical portion 210 from multiple locations (seven locations in this embodiment) on the inner end surface of the inner flat plate portion 212 that forms the hole portion 213. The bulging portion 212a bulges slightly in a convex arc shape, and is formed in a portion of the inner end surface of the inner flat plate portion 212 that is closer to the central axis of the cylindrical portion 210 than the long hole 214. As shown in FIG. 5, the small protrusion 210a has a substantially elliptical shape when viewed from below, and bulges downward from multiple locations (eight locations in this embodiment) on the end surface of the lower portion of the cylindrical portion 210. The small protrusion 210a bulges slightly in a convex arc shape, and the eight small protrusions 210a are arranged so that adjacent small protrusions 210a, 210a are spaced at 45 degrees from the central axis of the cylindrical portion 210.

The method of attaching the modified first impact body 21 shown in FIG. 4 to the coil spring 20 is the same as that of the first impact body 21 shown in FIG. 3, so a description thereof will be omitted. Note that the modified first impact body 21 can also be used as the second impact body 22.

[Pitch density of coil springs]
6 is a diagram for explaining in detail the pitch density of the coil spring and the wire diameter constituting the coil spring. Here, stainless steel SUS304 is used as the material.
The coil spring shown in FIG. 6(a) has a wire diameter of 1.4 mm and an outer diameter (wound diameter) of 36 mm. The natural length of the spring (length when laid horizontally) is 108.5 mm. The length of the densely wound part (6 coils) without any gaps at one end is 8.4 mm. The length of the densely wound part (7 coils) without any gaps at the center is 9.8 mm. The length of the densely wound part (2 coils) without any gaps at the other end is 2.8 mm. The length of the part (part with sparse pitch) between the densely wound part at one end and the densely wound part at the center is 38.5 mm (18 turns x 1.4 mm + 19 spaces x 0.7 mm = 25.2 mm + 13.3 mm). The length of the part (part with sparse pitch) between the densely wound part at the other end and the densely wound part at the center is 49.0 mm (23 turns x 1.4 mm + 24 spaces x 0.7 mm = 32.2 mm + 16.8 mm).

The coil spring shown in Figure 6 (b) has a wire diameter of 1.4 mm and an outer diameter (winding diameter) of 36 mm. The natural length of the spring (length when laid horizontally) is 108.5 mm. The length of the densely wound part at one end (6 coils densely) with no gaps is 8.4 mm. The length of the densely wound part at the center (7 coils densely) with no gaps is 9.8 mm. The length of the densely wound part at the other end (2 coils densely) with no gaps is 2.8 mm. The length of the part between the densely wound part at one end and the densely wound part at the center (part with sparse pitch) is 40.4 mm (18 turns x 1.4 mm + 19 gaps x 0.8 mm = 25.2 mm + 15.2 mm). The length of the section between the densely wound section at the other end and the densely wound section in the center (the section with a sparse pitch) is 47.0 mm (21 turns x 1.4 mm + 22 gaps x 0.8 mm = 29.4 mm + 17.6 mm).

The coil spring shown in Fig. 6(c) has a wire diameter of 1.4 mm and an outer diameter (wound diameter) of 36 mm. The natural length of the spring (length when laid horizontally) is 109.6 mm. There are no densely wound portions at either end, as in the coil springs shown in Figs. 6(a) and (b). The length of the densely wound portion (8 coils densely) with no space in the center is 11.2 mm. The length of the portion between one end and the densely wound portion in the center (part with sparse pitch) is 49.2 mm (22 turns x 1.4 mm + 23 spaces x 0.8 mm = 30.8 mm + 18.4 mm). The length of the portion between the other end and the densely wound portion in the center (part with sparse pitch) is 49.2 mm (22 turns x 1.4 mm + 23 spaces x 0.8 mm = 30.8 mm + 18.4 mm).

The coil spring shown in Figure 7 (a) has a wire diameter of 1.3 mm and an outer diameter (winding diameter) of 36 mm. The natural length of the spring (length when laid horizontally) is 105.1 mm. The length of the densely wound part at one end (6 coils densely) with no gaps is 7.8 mm. The length of the densely wound part at the center (7 coils densely) with no gaps is 9.1 mm. The length of the densely wound part at the other end (2 coils densely) with no gaps is 2.6 mm. The length of the part between the densely wound part at one end and the densely wound part at the center (part with sparse pitch) is 38.6 mm (18 turns x 1.3 mm + 19 gaps x 0.8 mm = 23.4 mm + 15.2 mm). The length of the section between the densely wound section at the other end and the densely wound section in the center (the section with a sparse pitch) is 47.0 mm (23 turns x 1.3 mm + 23 gaps x 0.8 mm = 28.6 mm + 18.4 mm).

The coil spring shown in FIG. 7(b) has a wire diameter of 1.3 mm and an outer diameter (wound diameter) of 36 mm. The natural length of the spring (length when laid horizontally) is 105.1 mm. The length of the densely wound part at one end (6 coils) is 7.8 mm. The length of the densely wound part at the center (7 coils) is 9.1 mm. The length of the densely wound part at the other end (2 coils) is 2.6 mm. The length of the part between the densely wound part at one end and the densely wound part at the center (part with sparse pitch) is 42.8 mm (18 turns x 1.3 mm + 21 spaces x 0.8 mm = 26.0 mm + 16.8 mm). The length of the part between the densely wound part at the other end and the densely wound part at the center (part with sparse pitch) is 42.8 mm (18 turns x 1.3 mm + 21 spaces x 0.8 mm = 26.0 mm + 16.8 mm).

The coil spring shown in Figure 8 (a) has a wire diameter of 1.3 mm and an outer diameter (winding diameter) of 36 mm. The natural length of the spring (length when laid horizontally) is 106.2 mm. The length of the densely wound part at one end (6 coils densely) with no gaps is 7.8 mm. The length of the densely wound part at the center (8 coils densely) with no gaps is 10.4 mm. The length of the densely wound part at the other end (2 coils densely) with no gaps is 2.6 mm. The length of the part between the densely wound part at one end and the densely wound part at the center (part with sparse pitch) is 38.7 mm (19 turns x 1.3 mm + 20 gaps x 0.7 mm = 24.7 mm + 14.0 mm). The length of the section between the densely wound section at the other end and the densely wound section in the center (the section with a sparse pitch) is 46.7 mm (23 turns x 1.3 mm + 24 gaps x 0.7 mm = 29.9 mm + 16.8 mm).

The coil spring shown in Figure 8 (b) has a wire diameter of 1.3 mm and an outer diameter (winding diameter) of 36 mm. The natural length of the spring (length when laid horizontally) is 106.2 mm. The length of the densely wound part at one end (6 coils densely) with no gaps is 7.8 mm. The length of the densely wound part at the center (8 coils densely) with no gaps is 10.4 mm. The length of the densely wound part at the other end (2 coils densely) with no gaps is 2.6 mm. The length of the part between the densely wound part at one end and the densely wound part at the center (part with sparse pitch) is 42.7 mm (21 turns x 1.3 mm + 22 gaps x 0.7 mm = 27.3 mm + 15.4 mm). The length of the section between the densely wound section at the other end and the densely wound section in the center (the section with a sparse pitch) is 42.7 mm (21 turns x 1.3 mm + 22 gaps x 0.7 mm = 27.3 mm + 15.4 mm).

When mixing protein powder with water, a spring wire diameter of 1.3 to 1.4 millimeters is suitable.

The appropriate natural length of the spring is 100 to 110 mm, which corresponds to 60% to 70% of the length of the storage section 10.

The spring pitch is preferably 7 to 8 tightly wound (closely wound) turns in the center, with a gap of 0.7 to 0.8 mm between the spring wires on both sides of the center.

Since the coil spring 20 is in a state in which it can slide inside the storage section 10, by shaking the storage section 10 up and down, the first collision body 21 hits the bottom surface of the storage section 10, and the second collision body 22 hits the underside of the flat plate section 11b of the upper opening/closing section 11, and the coil spring 20 slides while vibrating inside the storage section 10. This makes it possible to break down the protein powder contained in the liquid in the storage section 10. Also, by shaking the storage section 10 sideways, it is possible to make the coil spring 20 hit the inner side surface of the storage section 10. This makes it possible to scrape off the protein powder adhering to the inner side surface of the storage section 10.

In addition, the coil spring 20 has a densely wound central portion and sparsely wound both sides of the central portion, so that the upper sparse portion expands and contracts more than the central portion, and the lower sparse portion expands and contracts less than the central portion. In addition, when the first collision body 21 hits the bottom of the storage unit 10, the densely wound central portion moves downward due to inertia, so that the upper sparse portion expands and contracts more than the central portion. Similarly, when the second collision body 22 hits the flat plate portion 11b of the upper opening and closing unit 11, the densely wound central portion moves upward due to inertia, so that the lower sparse portion expands and contracts more than the central portion. Here, the protein powder has a variation in grain size, and when mixed with water, the larger grains move downward. As a result, by repeatedly shaking the storage unit 10 up and down or shaking the storage unit 10 upside down, it becomes easier to apply vibration to the lower sparse portion of the coil spring 20 relative to the central portion on the large grains.

[Mechanism of action]
The action and mechanism of the stirring device 1 of this embodiment can be explained from two perspectives.
First, the coil spring vibrates and swings to stir the liquid, shearing and breaking down lumps of oil, particles, and sediment into smaller particles, which are then dispersed into the liquid.

Secondly, the effect and mechanism of harmonic resonance (scaling resonance) of sound may be considered.
When a liquid material is stored in the storage section 10 of the stirring device 1, the upper opening/closing section 11 to which the cap section 12 is attached is closed, and a user holds the device in his/her hand and shakes it, an impact is applied to the coil spring 20. The impact causes the coil spring 20 to vibrate and swing. As the vibration and swing are transmitted, sound is generated (not limited to sounds in the audible range, but also including sounds lower than the audible range or sounds higher than the audible range). If the user shakes the stirring device 1 multiple times, this sound also continues to be generated.

On the other hand, clumps of protein powder particles and sediment mixed in the liquid are thought to exist as molecular clusters. When these collide with each other, sound is also produced.

The sound generated by the vibration and swinging of the coil spring and the sound generated when clusters of molecules mixed in the liquid collide can have an overtone (harmonic) relationship. The overtones (harmonics) of the sound generated by the vibration and swinging of the spring cause overtone resonance (scaling resonance) when clusters of molecules mixed in the liquid collide with each other. This promotes mixing and stirring of the liquid, and ultimately the dispersion of oil, particles, sediments, etc.

Here, scaling resonance is a phenomenon in which resonance occurs at harmonics (overtones) several tens of octaves higher. This is a concept used in "Music of Proteins" (Yoichi Fukagawa, Chikuma Primer Books).

Although resonance and sympathetic vibration are similar concepts, in this specification they will be considered separately. For example, when two strings are fixed to the same metal frame (solid), and one of them is vibrated, the other also vibrates. In this case, the vibration is transmitted through the solid material of the wooden metal frame, so this is resonance. On the other hand, when sound travels through a fluid such as water or air, resulting in vibration, this is resonance.

In the case of the stirring device 1 of this embodiment, the vibration is transmitted from the coil spring 20 to the particles, sediment, and other molecules via the fluid (liquid). Therefore, it should be called resonance. It is believed that harmonic resonance or scaling resonance of sound is at work here.

In the agitator 1 of this embodiment, when we look at the macro behavior of the liquid, when the user shakes it, the liquid moves, impacting the coil spring and causing it to vibrate and rock. On the other hand, when we look at the micro behavior of the liquid, clusters (lumps of several molecules stuck together) of particles, sediments, etc. contained in the liquid are subjected to a force due to harmonic resonance or scaling resonance that reduces the size of the clusters. This causes a shear effect, which causes the particles, sediments, etc. to reduce their clusters and mix evenly. This makes it possible for the agitator 1 of this embodiment to create a protein liquid that is smoother on the tongue.

In the stirring device 1 of this embodiment, since the center of the coil spring 20 is dense, when the stirring device 1 is swung up and down, the width of expansion and contraction on both sides of the center of the coil spring 20 can be alternately changed. For example, at the moment when the first collision body 21 collides with the bottom surface of the storage section 10, the lower part of the coil spring 20 shrinks more than the upper part. As a result, the impact when the first collision body 21 collides with the bottom surface of the storage section 10 is absorbed by the lower part of the coil spring 20, so that the impact sound can be reduced. Similarly, at the moment when the second collision body 22 collides with the flat plate portion 11b of the upper opening and closing section 11, the upper part of the coil spring 20 shrinks more than the lower part. As a result, the impact when the second collision body 22 collides with the flat plate portion 11b of the upper opening and closing section 11 is absorbed by the upper part of the coil spring 20, so that the impact sound can be reduced. In particular, as shown in FIG. 5, if the first impact body 21 and the second impact body 22 have small protrusions 210a and 220a, the small protrusions 210a and 220a collide with the bottom surface of the storage unit 10 and the flat plate portion 11b of the upper opening/closing unit 11, so that the area of the first impact body 21 and the second impact body 22 that collide with the bottom surface of the storage unit 10 and the flat plate portion 11b of the upper opening/closing unit 11 is reduced, and it is possible to reduce the collision sound. Moreover, each time the storage unit is swung once, the coil spring 20 can be collided twice with the bottom surface of the storage unit 10 and the lower surface of the flat plate portion 11b of the upper opening/closing unit 11, and the coil spring 20 can be finely vibrated with each collision. This reduces the powdery texture of powdered food and makes it possible to produce a liquid that is easy to swallow.

In the stirring device 1 of this embodiment, the first collision body 21 and the second collision body 22 are attached to both ends of the coil spring 20, so that the coil spring 20 does not come into direct contact with the bottom surface of the storage section 10 or the underside of the flat section 11b of the upper opening/closing section 11, and damage to the bottom surface of the storage section 10 or the underside of the flat section 11b of the upper opening/closing section 11 can be prevented.

In the agitator 1 of this embodiment, when the agitator 1 is swung up and down, water pressure can be applied to the bottom surface of the storage unit 10 and the flat plate portion 11b of the upper opening/closing portion 11 by the end surfaces of the cylindrical portions 210, 220 of the first collision body 21 and the second collision body 22, the upper and lower surfaces of the inner flat plate portions 212, 222, and the upper and lower surfaces of the horizontal plane portions 216, 226, making it possible to diffuse the protein powder precipitate on the bottom surface of the storage unit 10 and the protein powder adhering to the vicinity of the upper opening/closing portion 11. Moreover, since the lower portion of the coil spring 20 is located near the bottom surface of the storage unit 10 where the precipitate is diffused, it is possible to position many windings of the coil spring 20 near the diffused precipitate, and the vibration of the coil spring 20 can be efficiently applied to the precipitate. In particular, as shown in FIG. 4 and FIG. 5, if the first impact body 21 has a bulge 212a and the second impact body 22 has a bulge 222a, the area of the lower surface of the inner flat plate portion 212 and the area of the upper surface of the inner flat plate portion 222 can be increased, so that water pressure can be applied more efficiently to the bottom surface of the storage unit 10 and the vicinity of the upper opening/closing portion 11, and sediment near the bottom surface of the storage unit 10 and attachments near the upper opening/closing portion 11 can be dispersed. In addition, since the long holes 214, 224 are formed in the inner flat plate portions 212, 222, when the first impact body 21 and the second impact body 22 move up and down, sediment near the bottom surface of the storage unit 10 and attachments near the upper opening/closing portion 11 pass through the long holes 214, 224 and are easily moved to the coil spring 20 side.

[Sieve test]
Next, a protein powder sieving test using the stirring device 1 of this embodiment will be described.
In this test, water and protein powder are placed in the storage section 10 of the agitator 1, the agitator 1 is shaken to mix, and the mixture is passed through the meshes of a sieve. The time it takes for the powder to pass through the meshes and the weight of the protein powder adhering to the meshes are then measured. In other words, the shorter the time it takes for the powder to pass through the meshes and the smaller the weight of the protein powder adhering to the meshes, the more fine the particles of the protein powder in the mixture are made by the agitation.

<What to prepare>
In order to carry out the protein powder sieve test, in addition to the stirring device 1,
Protein powder: 10g,
Water: 100ml,
Flour sieve: wire diameter 0.16 mm, mesh size 0.50 mm square,
Timer, scale,
Prepare the following.

<Test Method>
First, the weight of the flour sieve is measured in advance.
Water and protein powder are placed in the container 10, and the container 10 is shaken up and down 10 times to mix. After that, the protein liquid in the container 10 is transferred to a powder sieve, and the time it takes for the protein liquid to pass through the powder sieve is measured.
Next, the powder sieve through which the protein liquid has passed is dried and then weighed, and the weight of the powder sieve is calculated by calculating the difference between the weight of the powder sieve through which the protein liquid has passed and the weight of the powder sieve before the protein liquid has passed, thereby obtaining the weight of the protein powder adhering to the meshes of the sieve.

<Test Results>
The above test was carried out in the case where the coil spring 20 was inserted into the storage section 10 as shown in Fig. 1, and the entire coil spring 20 was slid and stirred within the storage section 10. This test is referred to as Test (1).
As a comparative example, the above test was performed in a case where one end of coil spring 20 was attached to the opening of storage section 10 as shown in Fig. 11, and coil spring 20 suspended within storage section 10 was expanded and contracted to stir the liquid. This test is referred to as test (2).
Fig. 9 is an explanatory diagram showing a comparison of the weight of protein powder adhering to the sieve mesh in Test (1) and Test (2). Fig. 10 is an explanatory diagram showing a comparison of the powder sieving time when the coil spring 20 is attached to the storage section 10 and when it is not attached. As a result of the above tests, the following values were obtained as shown in Figs. 9 and 10. In Figs. 9 and 10, the left side shows the results of Test (2) and the right side shows the results of Test (1).

<Test (1)>
When the entire coil spring 20 is inserted into the storage section 10 (this embodiment)
Weight of the flour sieve after passing the protein liquid: 24.2252 g (A)
Weight of the flour sieve before passing the protein liquid: 24.1344 g ... (B)
Weight of protein powder adhering to the sieve mesh: (A)-(B)=0.0908 g
Flour sifting time: 5.74 seconds

<Test (2)>
When one end of the coil spring 20 is attached to the opening of the storage section 10 (Comparative Example)
Weight of the flour sieve after passing the protein liquid: 23.0224 g (A)
Weight of the flour sieve before passing the protein liquid: 22.8229 g ... (B)
Weight of protein powder adhering to the sieve mesh: (A)-(B)=0.1995 g
Flour sifting time: 6.04 seconds

Figure 10 shows a photograph of the sieve surface after the stirred protein liquid in tests (1) and (2) was passed through it. As is clear from Figure 10, the powder sieve through which the stirred protein liquid in test (1) was passed had less protein powder adhering to it than the powder sieve through which the stirred protein liquid in test (2) was passed through it. Thus, as shown in Figure 1, inserting the coil spring 20 into the storage section 10 and stirring by sliding the entire coil spring 20 within the storage section 10 results in smaller grains of protein powder than attaching one end of the coil spring 20 to the opening of the storage section 10 as shown in Figure 11 and stirring by expanding and contracting the coil spring 20 suspended within the storage section 10.

The above test was carried out without attaching the coil spring 20 to the storage section 10. The results are as follows.
When the coil spring 20 is not attached to the storage section 10, the weight of the flour sieve after the protein liquid has passed through it: 23.5606 g (A)
Weight of the flour sieve before passing the protein liquid: 22.8644 g ... (B)
Weight of protein powder adhering to the sieve mesh: (A)-(B)=0.6962 g
Powder sieving time: 13.26 seconds Figure 12 shows the sieve surface after the stirred protein liquid was passed through without the coil spring 20 attached to the storage section 10. Comparing Figure 12 with Figure 10, more protein powder adheres to the sieve surface when the coil spring 20 is stored in the storage section 10 as in tests (1) and (2) than when the coil spring 20 is not stored in the storage section 10. In other words, the results show that the protein powder particles are smaller when the coil spring 20 is attached.

As described above, as shown in FIG. 1, inserting the coil spring 20 into the storage section 10 and sliding the entire coil spring 20 inside the storage section 10 to stir the protein liquid takes less time to pass through the sieve mesh and reduces the weight of the protein powder adhering to the sieve mesh than attaching one end of the coil spring 20 to the opening of the storage section 10 as shown in FIG. 11 and stirring the coil spring 20 hanging down inside the storage section 10 by expanding and contracting it. Therefore, by inserting the coil spring 20 into the storage section 10 and stirring the protein liquid, it is possible to break down the particles of the protein powder in the protein liquid into smaller particles. This makes it possible to provide a protein liquid with reduced powderiness and a smooth texture. By removing the cap section 12, the user can drink the protein liquid in the storage section 10 from the upper cylindrical section 11c of the upper opening/closing section 11.

Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to those described above. For example, according to the above-mentioned embodiment, an example of mixing protein powder with water to make a protein liquid has been described, but the present invention is not limited to protein powder, and may also be a soft drink powder. Furthermore, the present invention may be used to drink powdered medicines. Furthermore, tablets may be placed in the storage section 10 and dissolved in water to a certain extent, and then the stirring device 1 may be shaken up and down and left and right. The present invention is not limited to powdered materials, and may also be used to mix liquid materials with water.

REFERENCE SIGNS LIST 1 Agitator 10 Storage section 10a Flat plate section 10b Cylindrical section 11 Upper opening/closing section 11a Lower cylindrical section 11b Flat plate section 11c Upper cylindrical section 12 Cap section 13 Free spring section 20 Coil spring 21 First impact body 22 Second impact body 21a, 22a Recess 210, 220 Cylindrical section 210a, 220a Small protrusion 212, 222 Inner flat plate section 212a, 222a Bulging section 213, 223 Hole section 214, 224 Long hole 215, 225 Wall section 216, 226 Horizontal surface section 217, 227 Side section 218, 228 Notch

Claims (8)

a storage section that stores the object to be dispersed and the liquid and extends vertically ;
an upper opening/closing section that is provided at an upper portion of the storage section and opens and closes an opening of the storage section so as to allow the object to be dispersed and the liquid to be put in and taken out;
a coil spring having a constant winding diameter, a dense pitch in a central portion, and a sparse pitch on both sides of the central portion; a first impact body attached to an upper end of the coil spring; and a second impact body attached to a lower end of the coil spring. A free spring portion is stored inside the storage portion.
and when the storage unit is shaken, the second impact body collides with a bottom surface of the storage unit, and the first impact body collides with a lower surface of the upper opening/closing unit, and a liquid material is generated by dispersing the object to be dispersed in the liquid by shaking,
a height of the coil spring of the free spring portion is shorter than a height of the storage portion, an outer diameter of the coil spring is shorter than an inner diameter of the storage portion, and when the storage portion is swung in the vertical direction, the coil spring is capable of sliding in the vertical direction inside the storage portion,
The first impact body and the second impact body are
a cylindrical portion into which an end of the coil spring can be inserted;
a donut-shaped flat plate portion extending from an upper end of the cylindrical portion toward a central axis of the cylindrical portion;
a sector-shaped recess formed at a corner between the cylindrical portion and the flat plate portion,
The dent is,
a wall portion extending vertically along a central axis from a part of a central hole formed in a central portion of the flat plate portion;
a horizontal surface portion extending from an end of the wall portion to the cylindrical portion;
A pair of side surfaces extending from both circumferential sides of the wall surface portion along both circumferential sides of the horizontal surface portion;
a cutout portion formed by cutting out a base portion of the pair of side surface portions where the pair of side surface portions are joined to the horizontal surface portion and the cylindrical portion,
The stirring device according to claim 1, wherein the notch has a width that allows an end of the coil spring to be inserted therethrough. 2. The stirring device according to claim 1 , wherein a plurality of protrusions are formed on a lower end surface of said cylindrical portion so as to protrude downward. 3. The stirring device according to claim 2 , wherein a plurality of bulges are formed on an inner end face of said flat plate portion, said bulging portions bulging toward a central axis of said cylindrical portion. 4. The stirring device according to claim 1, 2 or 3, wherein a plurality of holes are formed in the flat surface of the flat plate portion. a storage section that stores the object to be dispersed and the liquid and extends vertically ;
an upper opening/closing section that is provided at an upper portion of the storage section and opens and closes an opening of the storage section so as to allow the object to be dispersed and the liquid to be put in and taken out;
a coil spring having a constant winding diameter, a dense pitch in a central portion, and a sparse pitch on both sides of the central portion; a first impact body attached to an upper end of the coil spring; and a second impact body attached to a lower end of the coil spring. A free spring portion is stored inside the storage portion.
the free spring portion is used in an agitator that, when the storage unit is shaken, causes the second impact body to impact a bottom surface of the storage unit and the first impact body to impact a lower surface of the upper opening/closing unit, and generates a liquid material by shaking the object to be dispersed in the liquid,
a height of the coil spring of the free spring portion is shorter than a height of the storage portion, an outer diameter of the coil spring is shorter than an inner diameter of the storage portion, and when the storage portion is swung in the vertical direction, the coil spring is capable of sliding in the vertical direction inside the storage portion,
The first impact body and the second impact body are
a cylindrical portion into which an end of the coil spring can be inserted;
a donut-shaped flat plate portion extending from an upper end of the cylindrical portion toward a central axis of the cylindrical portion;
a sector-shaped recess formed at a corner between the cylindrical portion and the flat plate portion,
The dent is,
a wall portion extending vertically along a central axis from a part of a central hole formed in a central portion of the flat plate portion;
a horizontal surface portion extending from an end of the wall portion to the cylindrical portion;
A pair of side surfaces extending from both circumferential sides of the wall surface portion along both circumferential sides of the horizontal surface portion;
a cutout portion formed by cutting out a base portion of the pair of side surface portions where the pair of side surface portions are joined to the horizontal surface portion and the cylindrical portion,
A free spring portion , wherein the notch portion has a width that allows the end of the coil spring to be inserted therethrough. 6. The free spring portion according to claim 5 , wherein a plurality of protrusions protruding downward are formed on a lower end surface of said cylindrical portion. 7. The free spring portion according to claim 6 , wherein a plurality of bulging portions bulging toward a central axis of the cylindrical portion are formed on an inner end face of the flat portion. 8. The free spring portion according to claim 5, 6 or 7, wherein a plurality of holes are formed in the flat surface of said flat portion.