Fluid micro-injection device

Abstract

The fluid micro-injection device according to an embodiment of the present invention includes: a base body, an actuator mounting cavity is defined in the base body, and a positioning hole is provided on the base body that is connected to the actuator mounting cavity; a lever, the lever is arranged in the actuator mounting cavity and the two ends of the lever are movable; an actuator, the actuator is telescopically arranged in the actuator mounting cavity, and the actuator is connected to one end of the lever to control the movement of the lever; a fluid seat, the fluid seat defines a fluid cavity and a flow channel connected to the fluid cavity, and the base body is provided on the fluid seat; a nozzle, the nozzle is provided on the fluid seat and connected to the fluid cavity; a movable element, at least a portion of the movable element is located in the positioning hole, the upper end of the movable element is engaged with the other end of the lever when the base body and the fluid seat are assembled, and is driven by the lever to move along the axial direction of the positioning hole, and the lower end of the movable element extends into the fluid cavity to open and close the nozzle. The fluid micro-injection device according to an embodiment of the present invention can effectively improve the quality of fluid injection.

Description

Technical Field

[0001] The present invention relates to a fluid micro-injection device. Background Art

[0002] Existing fluid micro-injection devices use a lever mechanism to swing directly, driving a closing element to move up and down along the axis of the fluid chamber, thereby opening and closing the closing element and the nozzle, and thus achieving fluid injection. Because the lever end slides horizontally against the upper surface of the closing element during the swinging process, the closing element is subjected to reciprocating lateral forces during its up and down movement. This, in turn, causes friction between the closing element and the guide element, affecting the fluid injection quality.

[0003] In addition, the existing fluid micro-injection device realizes the transmission of displacement and force by the tangency between the large arc concave surface of the lever and the small cylindrical surface of the lever shaft. However, due to the uncertain tangency position of the large arc and the small cylinder, the lever amplification ratio is different, which affects the consistency of multiple sets of fluid micro-injection devices. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] To this end, the present invention provides a fluid micro-injection device, which can improve fluid injection quality and is easy to use.

[0006] According to an embodiment of the present invention, a fluid micro-injection device includes: a base, an actuator mounting cavity is defined in the base, and a positioning hole is provided on the base, which is connected to the actuator mounting cavity; a lever, the lever is arranged in the actuator mounting cavity and both ends of the lever are movable; an actuator, the actuator is telescopically arranged in the actuator mounting cavity, and the actuator is connected to one end of the lever to control the movement of the lever; a fluid seat, a fluid cavity and a flow channel connected to the fluid cavity are defined in the fluid seat, and the base is provided on the fluid seat; a nozzle, the nozzle is provided on the fluid seat and connected to the fluid cavity; a movable element, at least a part of the movable element is located in the positioning hole, the upper end of the movable element is engaged with the other end of the lever when the base and the fluid seat are assembled, and is driven by the lever to move along the axial direction of the positioning hole, and the lower end of the movable element extends into the fluid cavity to open and close the nozzle.

[0007] According to an embodiment of the present invention, the fluid micro-injection device combines a base, a lever, an actuator, a fluid seat, a nozzle and a movable element. By making the upper end of the movable element engage with the lever, it not only facilitates the installation and disassembly of the movable element, but also prevents the end of the lever from sliding horizontally between the upper plane of the movable element during the swinging process, thereby effectively reducing the friction between the lever and the movable element, improving the quality of fluid injection, and effectively transmitting the output displacement and force of the actuator.

[0008] According to one embodiment of the present invention, the movable element includes: a cylindrical shaft, which is movably arranged in the positioning hole along its axial direction; a clamping piece, which is arranged at the upper end of the cylindrical shaft, at least a portion of the clamping piece extends out of the outer circumferential surface of the cylindrical shaft, and the clamping piece is clamped with the other end of the lever.

[0009] According to one embodiment of the present invention, the other end of the lever is provided with a mounting hole extending through in an up-down direction for assembling the movable element.

[0010] According to one embodiment of the present invention, the lever includes: a lever body, both ends of the lever body are movable, one end of the lever body is connected to the actuator, and the other end of the lever body is provided with the mounting hole; a stop part, the stop part is provided above the lever body and at least a part of it is arranged opposite to the mounting hole, a plug-in slot is defined between the stop part and the lever body, the upper end of the clip located in the plug-in slot abuts against the stop part, and the lower end of the clip abuts against the lever body.

[0011] According to one embodiment of the present invention, the movable element is a T-shaped piece.

[0012] According to one embodiment of the present invention, the clamping member includes: two limiting portions, which are spaced apart and distributed along the axial direction of the cylindrical axis, one of the limiting portions is located above the lever body, and the other limiting portion is located below the lever body.

[0013] According to one embodiment of the present invention, the upper end surface of the lever body and / or the lower end surface of the lever body are provided with a protrusion protruding from the lever body.

[0014] According to one embodiment of the present invention, the protrusion is an arc-shaped protrusion.

[0015] According to one embodiment of the present invention, the protrusions are provided on both sides of the mounting hole.

[0016] According to one embodiment of the present invention, the mounting hole is provided on an edge of one end of the lever.

[0017] According to one embodiment of the present invention, the movable element includes: an upper movable part, the upper end of which is engaged with the lever; and a lower movable part, the upper end of which is detachably connected to the lower end of the upper movable part, and the lower end of the lower movable part cooperates with the nozzle.

[0018] According to one embodiment of the present invention, the upper surface of one end of the lever is provided with an arc-shaped groove extending along the thickness direction thereof, and the fluid micro-injection device further comprises: an actuator lower top block, the actuator lower top block is arranged at the lower end of the actuator, and the lower end of the actuator lower top block is provided with an arc-shaped protrusion, and the arc-shaped protrusion is inserted into the arc-shaped groove.

[0019] According to one embodiment of the present invention, the curvature radius of the arc-shaped protrusion is smaller than or equal to the curvature radius of the arc-shaped groove.

[0020] According to one embodiment of the present invention, a positioning groove is provided on the base, and a matching concave surface is provided on the lower surface of one end of the lever. The fluid micro-injection device also includes: a swing pin, at least a portion of the swing pin is inserted into the matching concave surface, and the lever is pivotally arranged in the actuator mounting cavity around the axis of the swing pin.

[0021] According to one embodiment of the present invention, the mating concave surface can be formed as an arc-shaped depression mating with the swing pin shaft, and the radius of the arc-shaped depression is less than or equal to the radius of the portion of the swing pin shaft inserted into the arc-shaped depression.

[0022] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments with reference to the following drawings, in which:

[0024] Figure 1 is a partial structural schematic diagram of a fluid micro-injection device according to one embodiment of the present invention;

[0025] Figure 2 yes Figure 1 Enlarged view of area A in the middle;

[0026] Figure 3 is a front view of a lever of a fluid micro-injection device according to one embodiment of the present invention;

[0027] Figure 4 is a top view of a lever of a fluid micro-injection device according to one embodiment of the present invention;

[0028] Figure 52 is a schematic structural diagram of a percussion hammer of a fluid micro-injection device according to an embodiment of the present invention;

[0029] Figure 6 is a partial structural schematic diagram of a fluid micro-injection device according to another embodiment of the present invention;

[0030] Figure 7 yes Figure 6 A magnified view of the A' region in the middle;

[0031] Figure 8 is a front view of a lever of a fluid micro-injection device according to another embodiment of the present invention;

[0032] Figure 9 is a top view of a lever of a fluid micro-injection device according to another embodiment of the present invention;

[0033] Figure 10 is a schematic structural diagram of a striker of a fluid micro-injection device according to another embodiment of the present invention;

[0034] Figure 11 1 is a schematic structural diagram of a lower top block of an actuator of a fluid micro-injection device according to an embodiment of the present invention;

[0035] Figure 12 1 is a schematic structural diagram of a swing pin of a fluid micro-injection device according to an embodiment of the present invention.

[0036] Reference numerals:

[0037] Fluid micro-injection device 200;

[0038] Actuator 4;

[0039] Matrix 5;

[0040] Actuator lower top block 6;

[0041] Lever 7; arc-shaped groove 7a; matching concave surface 7b; protrusion 7c; plug-in groove 7'c;

[0042] Swing pin 8; small cylindrical surface 8a; positioning side surface 8b; positioning bottom surface 8c;

[0043] Impact hammer 23; limiting portion 23a; cylindrical shaft 23d;

[0044] Firing pin 27;

[0045] Fluid seat 30;

[0046] Nozzle 35. DETAILED DESCRIPTION

[0047] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0048] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0049] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0050] A fluid micro-ejection device 200 according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0051] like Figures 1 to 12 As shown, the fluid micro-injection device 200 according to an embodiment of the present invention includes: a base 5, a lever 7, an actuator 4, a fluid seat 30, a nozzle 35 and a movable element.

[0052] Specifically, an actuator mounting cavity is defined in the base 5, a positioning hole communicating with the actuator mounting cavity is provided on the base 5, a lever 7 is provided in the actuator mounting cavity and both ends of the lever 7 are movable, the actuator 4 is telescopically provided in the actuator mounting cavity, the actuator 4 is connected to one end of the lever 7 to control the movement of the lever 7, a fluid cavity and a flow channel communicating with the fluid cavity are defined in the fluid seat 30, the base 5 is provided on the fluid seat 30, the nozzle 35 is provided on the fluid seat 30 and communicated with the fluid cavity, at least a portion of the movable element is located in the positioning hole, and the upper end of the movable element is engaged with the other end of the lever 7 when the base 5 and the fluid seat 30 are assembled, and is driven by the lever 7 to move along the axial direction of the positioning hole, and the lower end of the movable element extends into the fluid cavity to open and close the nozzle 35.

[0053] In other words, the fluid micro-injection device 200 according to an embodiment of the present invention primarily consists of a base 5, a lever 7, an actuator 4, a fluid seat 30, a nozzle 35, and a movable element. The base 5 has an actuator mounting cavity, within which the lever 7 and actuator 4 are mounted. When the base 5 extends vertically, the fluid seat 30 is located below the base 5, and the nozzle 35 is located above the fluid seat 30. The movable element connected to the nozzle 35 enables the nozzle 35 to be opened and closed, thereby controlling the flow rate of fluid flowing from the nozzle 35. Specifically, the lever 7 has movable ends, and the actuator 4 is mounted above one end of the lever 7, which is extendable vertically. Adjusting the vertical position of the actuator 4 allows the inclination of the lever 7 to be adjusted. The base 5 also has a positioning hole through which the upper end of the movable element can pass and engage with the other end of the lever 7. This provides not only a secure connection structure but also eases assembly and disassembly. Thus, by cooperating with the actuator 4 and the lever 7 , the movable element can be driven to move back and forth along the axial direction of the positioning hole, thereby achieving control over the flow rate of the fluid.

[0054] Therefore, the fluid micro-injection device 200 according to an embodiment of the present invention adopts a combination of a base 5, a lever 7, an actuator 4, a fluid seat 30, a nozzle 35 and a movable element. By making the upper end of the movable element engage with the lever 7, it is not only convenient for installing and disassembling the movable element, but also can prevent the end of the lever 7 from sliding horizontally with the upper plane of the movable element during the swinging process, can effectively reduce the friction between the lever 7 and the movable element, improve the fluid injection quality, and can also effectively transmit the output displacement and force of the actuator 4.

[0055] According to one embodiment of the present invention, Figure 5As shown, the movable element includes a cylindrical shaft 23d and a clamping piece. The cylindrical shaft 23d is movably arranged in the positioning hole along its axial direction. The clamping piece is arranged at the upper end of the cylindrical shaft 23d. At least a part of the clamping piece extends out of the outer peripheral surface of the cylindrical shaft 23d. The clamping piece is clamped with the other end of the lever 7. That is to say, when the cylindrical shaft 23d extends in the up and down directions, a clamping piece is provided above the cylindrical shaft 23d, and the clamping piece can be used to realize the clamping connection between the movable element and the lever 7.

[0056] Furthermore, if Figure 4 and Figure 9 As shown, the other end of lever 7 is provided with a mounting hole extending vertically therethrough for assembling the movable element. Specifically, cylindrical shaft 23d is passed through the mounting hole, with the engaging member positioned above the mounting hole. Preferably, one side of the mounting hole is open, facilitating the insertion of cylindrical shaft 23d through the open end and into the mounting hole, effectively transmitting the output displacement and force of actuator 4.

[0057] Alternatively, as Figure 8 and Figure 9 As shown, the lever 7 includes: a lever body and a stopper, both ends of the lever body are movable, one end of the lever body is connected to the actuator 4, and the other end of the lever body is provided with a mounting hole, the stopper is provided above the lever body and at least a portion thereof is arranged opposite to the mounting hole, a plug-in slot 7'c is defined between the stopper and the lever body, the upper end of the clip located in the plug-in slot 7'c is abutted against the stopper, and the lower end of the clip is abutted against the lever body, by adopting the stopper, not only can the clip be prevented from falling out of the mounting hole, but also it is conducive to forming line contact, reducing the influence of friction, and ensuring the displacement and force transmission of the actuator 4.

[0058] Alternatively, as Figure 10 As shown, the movable element is a T-shaped piece, which is easy to process, produce and use.

[0059] In some specific embodiments of the present invention, Figure 5 As shown, the clamping member includes two limiting portions 23a, which are spaced apart along the axial direction of the cylindrical shaft 23d. One limiting portion 23a is located above the lever body, and the other limiting portion 23a is located below the lever body. When the cylindrical shaft 23d extends in the vertical direction, the two limiting portions 23a are spaced apart and distributed along the outer circumference of the cylindrical shaft 23d in the vertical direction. When the cylindrical shaft 23d is installed in the mounting hole, one limiting portion 23a is located above the lever body, and the other limiting portion 23a is located below the lever body. The limiting portions 23 can be tangentially engaged with the lever 7, facilitating line contact, reducing the influence of friction, and ensuring the displacement and force transmission of the actuator 4.

[0060] Furthermore, if Figure 3 and Figure 4As shown, the upper end surface of the lever body and / or the lower end surface of the lever body are provided with a protrusion 7c protruding from the lever body. When the number of the protrusions 7c is two, the two protrusions 7c can be in tangential contact with the planes of the two limiting portions 23a, which is conducive to forming line contact, reducing the influence of friction, and ensuring the displacement and force transmission of the actuator 4.

[0061] Preferably, the protrusion 7c is an arc-shaped protrusion.

[0062] Furthermore, protrusions 7c are provided on both sides of the mounting hole.

[0063] According to one embodiment of the present invention, Figure 4 and Figure 9 As shown, the mounting hole is provided at one end edge of the lever 7, that is, one side of the mounting hole is open, which is not only convenient for installing the movable element, but also can effectively transmit the output displacement and force of the actuator 4.

[0064] In some specific embodiments of the present invention, the movable element includes an upper movable portion and a lower movable portion. The upper end of the upper movable portion is engaged with the lever 7, the upper end of the lower movable portion is detachably connected to the lower end of the upper movable portion, and the lower end of the lower movable portion is engaged with the nozzle 35. In other words, the movable element can also be a split structure. It should be noted that when a split structure is adopted, the upper movable portion can be referred to as the striker 23, and the lower movable portion can be referred to as the striker 27. The striker 27 can also adopt a segmented striker structure or a single-piece striker structure.

[0065] According to one embodiment of the present invention, an arc-shaped groove 7a is provided on the upper surface of one end of the lever 7 and extends in the thickness direction thereof. The fluid micro-injection device 200 further includes an actuator lower top block 6, which is provided at the lower end of the actuator 4. Figure 3 As shown, the lower end of the actuator lower top block 6 is provided with an arc-shaped protrusion 7c, which is inserted into the arc-shaped groove 7a. By matching the arc-shaped groove 7a with the arc-shaped protrusion 7c of the actuator 4 top block, the positioning effect of the actuator 4 can be improved.

[0066] Furthermore, the curvature radius of the arc-shaped protrusion 7 c is less than or equal to the curvature radius of the arc-shaped groove 7 a , which is conducive to forming line contact, reducing the influence of friction, and ensuring the displacement and force transmission of the actuator 4 .

[0067] According to one embodiment of the present invention, a positioning groove is provided on the base 5, such as Figure 3As shown, the lower surface of one end of lever 7 is provided with a mating concave surface 7b. Fluid micro-injection device 200 also includes a swing pin 8, at least a portion of which is inserted into mating concave surface 7b. Lever 7 is pivotally mounted within the actuator mounting cavity about the axis of swing pin 8. The fixed connection position between mating concave surface 7b and swing pin 8 ensures a consistent amplification ratio of lever 7, thereby ensuring consistency across multiple sets of fluid micro-injection devices 200.

[0068] It should be noted that if Figure 12 As shown, the swing pin 8 is provided with a small cylindrical surface 8a, a positioning side surface 8b and a positioning bottom surface 8c. The small cylindrical surface 8a cooperates with the matching concave surface 7b and has the same radius, so that the swing pin 8 can be positioned in the base 5 and remain stationary. The positioning side surface 8b can cooperate with the upper groove side surface of the base 5, so that the swing pin 8 can be positioned in the base 5 and remain stationary, ensuring the output displacement of the actuator 4 and the stable transmission of force. The positioning bottom surface 8c cooperates with the upper groove bottom surface on the base 5, so that the swing pin 8 can be positioned in the base 5 and remain stationary, limiting the installation height of the lever 7 for easy assembly.

[0069] Furthermore, the mating concave surface 7b can be formed into an arc-shaped depression that cooperates with the swing pin 8. The radius of the arc-shaped depression is less than or equal to the radius of the part of the swing pin 8 that is inserted into the arc-shaped depression, which is conducive to forming a fixed rotation position and ensuring accurate and stable amplification ratio and force transmission.

[0070] In summary, the fluid micro-injection device 200 according to an embodiment of the present invention adopts a device that combines a base 5, a lever 7, an actuator 4, a fluid seat 30, a nozzle 35 and a movable element. By effectively preventing the end of the lever 7 from sliding horizontally with the upper plane of the movable element during the swinging process, it can not only effectively reduce the friction between the lever 7 and the movable element and improve the fluid injection quality, but also effectively transmit the output displacement and force of the actuator 4.

[0071] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0072] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A fluid micro-injection device, characterized in that: include: A base body, wherein an actuator installation cavity is defined in the base body, a positioning hole communicating with the actuator installation cavity is provided on the base body, and a positioning groove is provided on the base body; a lever, the lever being disposed in the actuator mounting cavity and having movable ends, the lower surface of one end of the lever being provided with a mating concave surface, and two first inclined surfaces extending from both sides of the mating concave surface; A swing pin, wherein the swing pin is provided with a small cylindrical surface, the small cylindrical surface cooperates with the mating concave surface, two second inclined surfaces extend from both sides of the small cylindrical surface, and the angle formed by the two first inclined surfaces is greater than the angle formed by the two second inclined surfaces; the lever is pivotally disposed in the actuator mounting cavity around the axis of the swing pin; an actuator, the actuator being telescopically disposed in the actuator mounting cavity and connected to one end of the lever to control the movement of the lever; a fluid seat, wherein a fluid cavity and a flow channel communicating with the fluid cavity are defined in the fluid seat, and the base is disposed on the fluid seat; a nozzle, the nozzle being disposed on the fluid seat and communicating with the fluid cavity; a movable element, wherein at least a portion of the movable element is located in the positioning hole, an upper end of the movable element is engaged with the other end of the lever when the base and the fluid seat are assembled, and is driven by the lever to move along the axial direction of the positioning hole, and a lower end of the movable element extends into the fluid cavity to open and close the nozzle; The active element comprises: a cylindrical shaft, the cylindrical shaft being movably disposed in the positioning hole along its axial direction; a clamping member, the clamping member being provided at the upper end of the cylindrical shaft, at least a portion of the clamping member extending out of the outer circumferential surface of the cylindrical shaft, and the clamping member being clamped to the other end of the lever; The other end of the lever is provided with a mounting hole which penetrates in the up-down direction, the cylindrical shaft is mounted in the mounting hole, and the clamping member is adapted to form a linear contact with the lever.

2. The fluid micro-injection device according to claim 1, characterized in that: The levers include: a lever body, wherein both ends of the lever body are movable, one end of the lever body is connected to the actuator, and the other end of the lever body is provided with the mounting hole; A stop portion is provided above the lever body and at least a portion thereof is arranged opposite to the mounting hole. A plug-in slot is defined between the stop portion and the lever body. The upper end of the clip located in the plug-in slot abuts against the stop portion, and the lower end of the clip abuts against the lever body.

3. The fluid micro-injection device according to claim 2, characterized in that: The movable element is a T-shaped piece.

4. The fluid micro-injection device according to claim 1, wherein: The clamping member comprises: Two limiting portions are spaced apart and distributed along the axial direction of the cylindrical shaft, one of the limiting portions is located above the lever body, and the other limiting portion is located below the lever body.

5. The fluid micro-injection device according to claim 4, characterized in that: The upper end surface of the lever body and / or the lower end surface of the lever body are provided with a protrusion protruding from the lever body.

6. The fluid micro-injection device according to claim 5, characterized in that: The protrusion is an arc-shaped protrusion.

7. The fluid micro-injection device according to claim 6, characterized in that: The protrusions are arranged on both sides of the mounting hole.

8. The fluid micro-injection device according to claim 1, wherein: The mounting hole is arranged on an edge of one end of the lever.

9. The fluid micro-injection device according to claim 1, characterized in that: The active element comprises: an upper movable portion, the upper end of which is engaged with the lever; The lower movable part has an upper end detachably connected to the lower end of the upper movable part, and the lower end of the lower movable part is matched with the nozzle.

10. The fluid micro-injection device according to claim 1, wherein: An arc-shaped groove extending in the thickness direction of the lever is provided on the upper surface of one end of the lever, and the fluid micro-injection device further comprises: The actuator lower top block is arranged at the lower end of the actuator, and the lower end of the actuator lower top block is provided with an arc-shaped protrusion, and the arc-shaped protrusion is inserted into the arc-shaped groove.

11. The fluid micro-injection device according to claim 10, characterized in that: The curvature radius of the arc-shaped protrusion is smaller than or equal to the curvature radius of the arc-shaped groove.

12. The fluid micro-injection device according to claim 1, wherein: The matching concave surface can be formed as an arc-shaped depression that matches the swing pin shaft, and the radius of the arc-shaped depression is less than or equal to the radius of the portion of the swing pin shaft that is inserted into the arc-shaped depression.

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