Container with adjustable opening cover
By designing a container with an adjustable opening lid, the problems of existing containers being unable to be resealed and being fragile are solved, enabling multiple uses and refilling, enhancing the container's practicality and its ability to prevent the contents from spoiling.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 斯科特·T·蒂曼
- Filing Date
- 2022-09-23
- Publication Date
- 2026-06-02
AI Technical Summary
Existing containers cannot be resealed after single use, and the removable cover element is fragile and difficult to refill, causing the contents to spoil easily.
A container with an adjustable opening lid is designed, comprising a can, a ring, a disc lid, and a tension spring. The adjustable opening is achieved through a threaded connection and a rotatable disc plate, and the sealing lid provides an airtight seal, allowing for multiple uses and refilling.
It enables multiple uses and refilling of the container, prevents contamination and spoilage of the contents, provides a variety of pouring and dispensing options, and enhances the container's practicality and durability.
Smart Images
Figure CN118201855B_ABST
Abstract
Description
[0001] Applicant and Inventor: Scott T. Timman (individual)
[0002] 935 Til Avenue
[0003] Fort Collins, Colorado 80521
[0004] USA
[0005] U.S. citizens and residents
[0006] Container with adjustable opening lid
[0007] Cross-references to related applications
[0008] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 248,435, filed September 25, 2021, entitled “Container Having Adjustable Opening Lid,” the entire contents of which are incorporated herein by reference for all that is disclosed and taught herein. Background Technology
[0009] Containers with an integrally arranged dispensing lid are widely used for the controlled dispensing of materials held within the container without removing the lid. For single-use containers, the dispensing lid initially provides a seal, and when the seal breaks or is otherwise irreversibly opened, it provides an opening whose size can be adjusted by means of a movable covering element, which itself has openings of different sizes. Because once a container is opened, it cannot be resealed without the use of additional materials such as aluminum foil or plastic packaging material, the contents are often consumed rapidly to prevent spoilage. Furthermore, the container is not easily refilled. Additionally, movable covering elements, which can be made of inexpensive plastic materials, are fragile and can be damaged by inserting metal utensils, such as spoons, into the large opening to remove the contents of the container. Summary of the Invention
[0010] According to the purpose of the invention, as embodied and broadly described herein, an embodiment of a container having an adjustable opening includes: a can having a flat circular opening and an outer surface with threads near the flat circular opening; an annulus having a circular flat edge of a selected inner diameter and threads suitable for screwing onto the threads of the can; a disc-shaped cover including: a first flat circular plate having a first axis, a first surface and a second surface, an outer diameter and a first selected pattern, the outer diameter such that the first circular plate is held between the flat opening of the can and the flat edge of the annulus, and the first selected pattern is formed inside the outer diameter of the first flat circular plate and outside the first axis, passing through the first flat circular plate; a second flat circular plate having a second axis collinear with the first axis of the first flat circular plate, a first surface and a second surface, a second outer diameter and a second selected pattern. The second outer diameter effectively allows a portion of the first surface of the second flat circular plate to cover all or part of the first selected pattern of the first flat circular plate, and is smaller than the inner diameter of the flat edge of the circular cover, the second selected pattern being formed through the second flat circular plate inside the second outer diameter; and a tension spring having a first end and a second end, the first end of which is formed together with or attached to the second surface of the second circular plate and forms a protrusion structure above the second surface; and means for attaching the second circular plate to the first circular plate such that the first surface of the first circular plate and the first surface of the second circular plate are rotatably in contact about a second axis, the tension spring providing adjustable pressure between the second circular plate and the first circular plate, and providing a handle for rotating the second circular plate.
[0011] Further according to the purpose of the invention, as embodied and broadly described herein, another embodiment of a container having an adjustable opening includes: a can having a flat circular opening and an outer surface with threads near the flat circular opening; an annulus having a flat circular edge of a selected inner diameter and threads adapted to be screwed onto the threads of the can; a disc-shaped cover including: a first flat circular plate having a first axis, a first surface and a second surface, an outer diameter and a first selected pattern, the outer diameter being such that the first circular plate is disposed adjacent to the flat edge of the annulus, and the first selected pattern being formed inside the outer diameter of the first flat circular plate and outside the first axis passing through the first flat circular plate; a second flat circular plate having a second axis collinear with the first axis of the first circular plate, a first surface and a second surface, a second outer diameter and a second selected pattern, the second outer diameter effectively allowing a portion of the first surface of the second circular plate to cover the first selected pattern of the first circular plate. The second selected pattern is formed, in whole or in part, smaller than the inner diameter of the flat edge of the circular cap, passing through the second flat circular plate inside the second outer diameter; and a tension spring having a first end and a second end, the first end of which is formed together with or attached to the second surface of the second circular plate and forms a raised structure above the second surface; a circular sealing cap having a first surface, a second surface, an outer diameter and a flat gasket attached to or otherwise disposed on the second surface, the circular sealing cap being held between the first flat circular plate and the flat opening of the can, forming an airtight seal with the flat circular opening of the can; and means for attaching the second circular plate to the first circular plate such that the first surface of the first circular plate is rotatably in contact with the first surface of the second circular plate about a second axis, the tension spring providing adjustable pressure between the second circular plate and the first circular plate and providing a handle for rotating the second circular plate.
[0012] Further according to the purposes of the invention, as embodied and broadly described herein, another embodiment of the disc-shaped cover with an adjustable opening comprises: a first flat circular plate having a first axis, a first surface and a second surface, an outer diameter, and a first selected pattern formed inside the outer diameter and outside the first axis through the first flat circular plate; a second flat plate having a first surface and a second surface for allowing a portion of the first surface of the second circular plate to cover all or part of the first selected pattern of the first circular plate, and the second flat plate also having a second selected pattern formed therethrough; a tension spring having a first end and a second end, the first end of which is formed together with or attached to the second surface of the second plate and forms a protrusion above the second surface; and means for attaching the second plate to the first circular plate such that the first surface of the first circular plate is rotatably in contact with the first surface of the second plate, the tension spring providing adjustable pressure between the second plate and the first circular plate, and providing a handle for rotating the second plate.
[0013] The benefits and advantages of this invention include, but are not limited to, providing a container comprising: a can having an open end and threads on an outer surface near the open end; a ring adapted to be screwed onto the threads to secure an adjustable opening cap, wherein a variety of pouring and dispensing options for materials placed in the container are feasible. Furthermore, the container can be sealed between uses and refilled as needed. Attached Figure Description
[0014] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings:
[0015] Figure 1 This is a top perspective view of an embodiment of the assembled container, which has an adjustable opening lid.
[0016] Figure 2A It is a top perspective view of the can portion of the container, which has a flat, circular opening and threads. Figure 2B It is a top perspective view of a ring or circular band having an open, round, flat edge and threads suitable for screwing onto a can component; Figure 2C It has two disc-shaped components or plates ( Figure 2C (a) and Figure 2C (b) A top perspective view of the disc-shaped cover, wherein the two disc-shaped components or plates can rotate relative to each other when not in use. Figure 2F When sealing the circular gasket as shown, the larger plate ( Figure 2C (a) Fixed below the flat edge of the ring against the opening of the can, each plate has a selected pattern passing through it, the smaller plate has a tension spring formed therewith or attached thereto, the tension spring forming a raised handle member, and each plate also has a respective... Figure 2C The mechanical screw shown in (b) and in Figure 2C The nut shown in (a) is used to attach the smaller plate ( Figure 2C (b) Attached to a larger component ( Figure 2C (a)) On the above, by using the protruding handle member, the smaller plate can be rotated relative to the larger member, so that a portion of the selected pattern of the smaller plate can partially overlap or cover a portion of the larger plate. Figure 2D yes Figure 2C A side view of the disc-shaped cover, showing two disc-shaped components or plates ( Figure 2D (a) and Figure 2D (b), with the above Figure 2C (a) and Figure 2C (b) shows the same plate), illustrating the use of machine screws and a threaded hole located in the center of the larger plate to install the smaller plate ( Figure 2D (b) Attached to a larger plate ( Figure 2D In another embodiment of (a)), the two plates can be rotated relative to each other by using a protruding handle member; Figure 2E This is a top-view perspective diagram of the components assembled into a disc-shaped cover; Figure 2F This is a top perspective view of a circular gasket sealing cap used for cans; Figure 2G This is a bottom view of the sealing cap, showing a flat gasket disposed on its bottom surface, inside the circumference, for forming an airtight seal between the sealing cap and the flat circular opening of the can.
[0017] Figure 3 yes Figure 1 The schematic side cross-sectional view of the assembled container shown illustrates a circular recess in the sealing cap, providing space for the attachment nuts of the two disc-shaped components.
[0018] Figure 4A yes Figure 2A A side perspective view of the tank component, showing a flat opening and threads; Figure 4B yes Figure 2B A side view of the annulus or circular band, showing the flat edges and threads suitable for screwing onto the can components; Figure 4C yes Figure 2F and Figure 2G The diagram shown is a side view of a circular gasket sealing cap for a can; and Figure 4D yes Figure 4A , Figure 4B and Figure 4C The diagram shows a top-view perspective of the components being assembled to reseal the container.
[0019] Figures 5A-5C yes Figure 2C (a) shows a top view of the larger circular plate, illustrating several patterns formed through the circular plate; Figure 5D and Figure 5E yes Figure 2C The smaller circular plate shown Figure 2C (b) is a top view diagram in which Figure 5D The pattern formed through the circular plate is shown, and Figure 5E This illustrates how a portion of a smaller circular plate is removed instead of being passed through to form a pattern. Detailed Implementation
[0020] In short, embodiments of the invention include a container comprising a glass jar and a ring. The glass jar has an open end and threads on its outer surface near the open end. The ring is adapted to be screwed onto the threads to secure an adjustable-opening cap. Numerous options for pouring and dispensing materials placed in the container are feasible, including using a tool to remove the contents of the container. Based on the teachings of embodiments of the invention, containers whose contents are sealed to prevent contamination and spoilage can be purchased. Furthermore, the container can be resealed and refilled after use.
[0021] Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. In the drawings, similar structures will be identified using the same reference numerals. It should be understood that the drawings are given to describe specific embodiments of the invention and are not intended to limit the invention thereto. Now turning to Figure 1 The diagram shows a top perspective view of an assembly embodiment of a container 10 with an adjustable opening. Figure 2A A can 12 is shown, having a flat, circular opening 14 and an outer surface 16 with threads 18 near the flat opening 14. For example, the can 12 may be a glass Mason jar. Figure 2B A ring or circular band 20 is shown, having an inwardly opening circular flat edge 22 and a thread 24, the edge 22 having a selected inner diameter 23, the thread 24 being adapted to be screwed onto the thread 18 of the can 12. Figure 2C The disc-shaped cover 26 shown includes a first flat circular plate 28. Figure 2C (a)), the first flat circular plate 28 has: a first axis 30 passing through its center, a first surface 32 and a second surface 34, an outer diameter 36, and a first selected pattern 38, the outer diameter 36 being such that when the following is not used... Figure 2F When the circular gasket sealing cap 37 is described, the first circular plate 28 is fixed between the flat opening 14 of the can 12 and the flat edge 22 of the ring 20, and the first selected pattern 38 is formed inside the outer diameter of the first circular plate 28 and outside the first axis through the first circular plate 28. Figure 2C The second flat circular plate 40 is also shown. Figure 2C (b) has a second axis 42 passing through its center and collinear with the first axis 30 of the first circular plate 28, a first surface 44 and a second surface 46, an outer diameter 48, and a second selected pattern 50. The outer diameter 48 effectively allows a portion of the first surface 44 of the second circular plate 40 to partially overlap or cover the first selected pattern 38 of the first circular plate 28 and is smaller than the inner diameter 23 of the edge 22 of the circular cover 20. The second selected pattern 50 is formed inside the outer diameter 48 through the second circular plate 40. It should be mentioned that the second rotating plate 40 does not necessarily have to be circular to achieve the above function, as described below. Figure 5E As shown in the image.
[0022] The tension spring or tension bar 52 has a first end 54 and a second end 56, the first end 54 being formed together with or attached to the second surface 46 of the second circular plate 40, and forming or bending into a protrusion above the second surface to provide a handle 57 for rotating the circular plate 40 relative to the circular plate 28. Figure 2C (b) and Figure 2C (a) A machine screw 58 is shown that is adapted to pass through the hole 60 in the tension spring 52, the hole 62 in the circular plate 40 and the hole 64 in the circular plate 28 and engage with the nut 66, and an embodiment is shown in which the smaller component 40 is attached to the larger component 28 in an adjustable manner. Figure 2D yes Figure 2C A side view of the disc-shaped cover, showing two circular plates 28 and 40 ( Figure 2D (a) and Figure 2D (b), with the above Figure 2C (a) and Figure 2C (b) shows the same circular plate), illustrating the use of machine screws 58 and threaded holes 64 now located in the center of plate 28 to attach a smaller plate ( Figure 2D (b) Attached to a larger plate ( Figure 2D In another embodiment of (a)), the two plates can be rotated relative to each other by using a raised handle member 57. Both embodiments also allow plates 28 and 40 to have adjustable resistance against relative rotation.
[0023] Figure 2E It is a top perspective view of the flat circular plates 28 and 40 assembled into a disc-shaped cover 26.
[0024] Figure 2F This is a top perspective view of the circular gasket sealing cap 37 used in tank 12, and Figure 2G This is a bottom view of the sealing cap 37, showing a flat gasket 68 attached or otherwise disposed on the bottom surface 70 of the sealing cap 37, inside the circumference 72, for forming an airtight seal between the sealing cap 37 and the flat circular opening 14 of the can 12. A flat circular recess 74 is also shown. The sealing cap 37 can be used to protect the contents of the container 10 from spoilage when sold on a shelf, and / or to reseal the container 10 after the contents have been dispensed (if it is not intended for further use immediately), which could otherwise lead to spoilage.
[0025] Figure 3 yes Figure 1 The side cross-sectional view of the assembled container shown illustrates a circular recess 74 in the sealing cap 37, which provides space for the attachment nuts 66 or threaded holes 64 of the two circular plates 28 and 40.
[0026] Figure 4A yes Figure 2A The side perspective view of the tank component 12 shown illustrates the flat circular opening 14 and the threads 18 on the outer surface 16. Figure 4B yes Figure 2B The side view of the ring 20 shown in the figure shows that the thread 24 is adapted to be screwed onto the thread 18 of the can component 12. Figure 4C yes Figure 2F and Figure 2G The schematic side view shown is of the circular gasket sealing cap 37 for the can. Figure 4D They are respectively in Figure 4A , Figure 4B and Figure 4C The diagram shows a top-view perspective of the components (i.e., 12, 20, and 37) being assembled to reseal the container.
[0027] The means for attaching the second circular plate 40 to the first circular plate 28 such that the first surface 32 of the first circular plate 28 and the first surface 44 of the second circular plate 40 are rotatably in contact about the second axis 42 are as described above, and as follows: Figure 2C and Figure 2D As shown, adjustable pressure is provided between circular plates 28 and 40. Other means for achieving rotatable assembly include other threaded fasteners and rivets. For example, in the case of rivets, adjustable pressure can be achieved by appropriately bending a tension spring or tension bar 52 after the two plates are in rotatable contact.
[0028] Figures 5A-5C yes Figure 2C (a) shows a top view of the circular plate 28, illustrating several patterns 38 formed through the circular plate 28; Figure 5D yes Figure 2C (b) shows a top view of the circular plate 40, illustrating the pattern 50 formed through the circular plate 40; Figure 5E yes Figure 2C (b) is a top view of the circular plate 40, showing a non-circular embodiment of the circular plate 40 with a portion removed compared to the circular plate 40 in which a pattern is formed. As described above, since the circular plates 28 and 40 can rotate relative to each other, the larger plate 28... Figure 2C and Figures 5A-5C The portion of the selected pattern shown may partially overlap with or be covered by a portion of the smaller plate 40.
[0029] The foregoing description of this invention is for illustrative and descriptive purposes and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Various modifications and variations will be apparent from the above teachings. These embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to best utilize the invention in various embodiments and with various modifications suitable for the intended particular use. The scope of the invention is intended to be defined by the appended claims.
Claims
1. A container having an adjustable opening, comprising: A can having a flat circular opening and an outer surface with threads near the flat circular opening; A ring having an open circular flat edge of a selected inner diameter and threads suitable for screwing onto the threads of the can; Disc-shaped cover, the disc-shaped cover comprising: A first flat circular plate has: a first axis, a first surface and a second surface, an outer diameter and a first selected pattern, the outer diameter such that the first flat circular plate is held between the flat opening of the can and the flat edge of the annulus, the first selected pattern being formed inside the outer diameter of the first flat circular plate and outside the first axis through the first flat circular plate. A second flat circular plate, the second flat circular plate having a second axis collinear with the first axis of the first flat circular plate, a first surface and a second surface, a second outer diameter and a second selected pattern, the second outer diameter effectively allowing a portion of the first surface of the second flat circular plate to cover a portion or all of the first selected pattern of the first flat circular plate, and being smaller than the inner diameter of the flat edge of the annulus, the second selected pattern being formed inside the second outer diameter through the second flat circular plate; and A tension spring having a first end and a second end, the first end of the tension spring being formed together with or attached to a second surface of a second flat circular plate, and having a protrusion structure formed above the second surface; and The means for attaching the second flat circular plate to the first flat circular plate such that a first surface of the first flat circular plate is in rotatable contact with a first surface of the second flat circular plate about a second axis, the tension spring providing adjustable pressure between the second flat circular plate and the first flat circular plate, and providing a handle for rotating the second flat circular plate.
2. The container of claim 1, wherein, The cans include Mason jars.
3. The container according to claim 1, wherein, The second flat circular plate is rotatable, such that a first selected pattern of the first flat circular plate and a second selected pattern of the second flat circular plate overlap to form an opening with a selected shape.
4. The container according to claim 3, wherein, The selected shape allows the appliance to be inserted into the jar.
5. The container according to claim 1, wherein, The first flat circular plate has a first hole passing through it along the first axis, the second flat circular plate has a second hole passing through it along the second axis, the tension spring has a hole passing through it near its second end, and the means for attaching the second flat circular plate to the first flat circular plate includes: a machine screw having a threaded portion adapted to be fitted through the first hole in the first flat circular plate, the second hole in the second flat circular plate, and the hole in the tension spring; and a nut for screwing onto the threaded portion of the machine screw, such that the pressure between the second flat circular plate and the first flat circular plate can be adjusted.
6. The container according to claim 1, wherein, The first flat circular plate has a first hole passing through it along the first axis, the second flat circular plate has a second hole passing through it along the second axis, the second hole having a threaded portion, the tension spring having a hole passing through it near its second end, and the means for attaching the second flat circular plate to the first flat circular plate includes a machine screw having a threaded portion adapted to fit through the first hole in the first flat circular plate and the hole in the tension spring, and adapted to be screwed into the threaded portion of the second hole, such that the pressure between the second flat circular plate and the first flat circular plate can be adjusted.
7. The container according to claim 1, wherein, The ring, the first flat circular plate, the second flat circular plate, and the tension spring are all made of metal.
8. The container of claim 1 further includes a circular sealing cap having a first surface, a second surface, an outer diameter, and a flat gasket attached to or otherwise disposed on the second surface, the circular sealing cap being held between the first flat circular plate and the flat circular opening of the can, and forming an airtight seal with the flat circular opening of the can.
9. A container having an adjustable opening, comprising: A can having a flat circular opening and an outer surface with threads near the flat circular opening; A ring having an open circular flat edge of a selected inner diameter and threads suitable for screwing onto the threads of the can; Disc-shaped cover, the disc-shaped cover comprising: A first flat circular plate has: a first axis, a first surface and a second surface, an outer diameter and a first selected pattern, the outer diameter being such that the first flat circular plate is disposed adjacent to the flat edge of the annulus, and the first selected pattern being formed inside the outer diameter of the first flat circular plate and outside the first axis, passing through the first flat circular plate. A second flat circular plate, the second flat circular plate having a second axis collinear with the first axis of the first flat circular plate, a first surface and a second surface, a second outer diameter and a second selected pattern, the second outer diameter effectively allowing a portion of the first surface of the second flat circular plate to cover all or part of the first selected pattern of the first flat circular plate, and being smaller than the inner diameter of the flat edge of the annulus, the second selected pattern being formed inside the second outer diameter through the second flat circular plate; and A tension spring having a first end and a second end, wherein the first end of the tension spring is formed together with or attached to the second surface of the second flat circular plate, and a protrusion structure is formed above the second surface; A circular sealing cap having a first surface, a second surface, a third outer diameter, and a flat gasket attached to or otherwise disposed on the second surface, the circular sealing cap being held between the first flat circular plate and the flat circular opening of the can, forming an airtight seal with the flat circular opening of the can; and The means for attaching the second flat circular plate to the first flat circular plate such that a first surface of the first flat circular plate is in rotatable contact with a first surface of the second flat circular plate about a second axis, the tension spring providing adjustable pressure between the second flat circular plate and the first flat circular plate, and providing a handle for rotating the second flat circular plate.
10. The container according to claim 9, wherein, The cans include Mason jars.
11. The container according to claim 9, wherein, The second flat circular plate is rotatable, such that a first selected pattern of the first flat circular plate and a second selected pattern of the second flat circular plate overlap to form an opening with a selected shape.
12. The container according to claim 11, wherein, The selected shape allows the appliance to be inserted into the jar.
13. The container according to claim 9, wherein, The first flat circular plate has a first hole passing through it along the first axis, the second flat circular plate has a second hole passing through it along the second axis, the tension spring has a hole passing through it near its second end, and the means for attaching the second flat circular plate to the first flat circular plate includes: a machine screw having a threaded portion adapted to be fitted through the first hole in the first flat circular plate, the second hole in the second flat circular plate, and the hole in the tension spring; and a nut for screwing onto the threaded portion of the machine screw, such that the pressure between the second flat circular plate and the first flat circular plate can be adjusted.
14. The container according to claim 9, wherein, The first flat circular plate has a first hole passing through it along the first axis, the second flat circular plate has a second hole passing through it along the second axis, the second hole having a threaded portion, the tension spring having a hole passing through it near its second end, and the means for attaching the second flat circular plate to the first flat circular plate includes a machine screw having a threaded portion adapted to fit through the first hole in the first flat circular plate and the hole in the tension spring, and adapted to be screwed into the threaded portion of the second hole, such that the pressure between the second flat circular plate and the first flat circular plate can be adjusted.
15. The container according to claim 9, wherein, The ring, the first flat circular plate, the second flat circular plate, the circular sealing cap, and the tension spring are all made of metal.
16. A disc-shaped cover with an adjustable opening, comprising: A first flat circular plate having a first axis, a first surface and a second surface, an outer diameter, and a first selected pattern formed inside the outer diameter of the first flat circular plate and outside the first axis passing through the first flat circular plate. The second flat plate has: a first surface and a second surface, for allowing a portion of the first surface of the second flat plate to cover all or a portion of a first selected pattern of the first flat circular plate; and a second selected pattern formed through the second flat plate; A tension spring having a first end and a second end, the first end of the tension spring being formed together with or attached to the second surface of the second flat plate, and having a protrusion structure formed above the second surface; and The means for attaching the second flat plate to the first flat circular plate is provided such that a first surface of the first flat circular plate is in rotatable contact with a first surface of the second flat plate, the tension spring provides adjustable pressure between the second flat plate and the first flat circular plate, and provides a handle for rotating the second flat plate.
17. The disc-shaped cover according to claim 16, wherein, The second flat plate includes a flat circular plate having: a second axis collinear with a first axis of the first flat circular plate; a second outer diameter that effectively allows a portion of a first surface of the second flat circular plate to cover all or part of a first selected pattern of the first flat circular plate; and a second selected pattern formed inside the second outer diameter through the flat circular plate.
18. The disc-shaped cover according to claim 17, wherein, The second flat circular plate is rotatable, such that a first selected pattern of the first flat circular plate and a second selected pattern of the second flat circular plate overlap to form an opening with a selected shape.
19. The disc-shaped cover according to claim 17, wherein, The first flat circular plate has a first hole passing through it along the first axis, the second flat circular plate has a second hole passing through it, the tension spring has a hole passing through it near its second end, and the means for attaching the second flat circular plate to the first flat circular plate includes: a machine screw having a threaded portion adapted to be fitted through the first hole in the first flat circular plate, the second hole in the second flat circular plate, and the hole in the tension spring; and a nut for screwing onto the threaded portion of the machine screw, such that the pressure between the second flat circular plate and the first flat circular plate can be adjusted.
20. The disc-shaped cover according to claim 17, wherein, The first flat circular plate has a first hole passing through it along the first axis, the second flat circular plate has a second hole passing through it, the second hole having a threaded portion, the tension spring has a hole passing through it near its second end, and the means for attaching the second flat circular plate to the first flat circular plate includes a machine screw with a threaded portion adapted to fit through the first hole in the first flat circular plate and the hole in the tension spring, and adapted to be screwed into the threaded portion of the second hole, such that the pressure between the second flat circular plate and the first flat circular plate can be adjusted.
21. The disc-shaped cover according to claim 17, wherein, The first flat circular plate, the second flat circular plate, and the tension spring are all made of metal.
22. The disc-shaped cover according to claim 16, wherein, The means for attaching the second flat plate to the first flat circular plate such that the first surface of the first flat circular plate is in rotatable contact with the first surface of the second flat plate is selected from threaded fasteners and rivets.