COVER PLATE ASSEMBLY AND CENTERING BAR

A cover plate assembly includes a first track of a first base plate that is affixed to a first structural member and a second track of a second base plate that is affixed to a second structural member. The cover plate assembly further includes a centering bar slidably engaged with the first track of the first base plate and the second track of the second base plate, and having a centering bar opening that receives a fastener. A guide is coupled to the centering bar and aligns the fastener with the centering bar opening, and a cover plate having a cover plate aperture aligns with the guide and the centering bar opening. A spring assembly is attached to the centering bar and receives the fastener after the fastener is inserted through the cover plate aperture and the centering bar opening.

TECHNICAL FIELD

The present disclosure relates to expansion joint cover assemblies, and more particularly, to a centering bar for an expansion joint cover assembly that allows for efficient alignment and installation of the expansion joint cover assembly.

BACKGROUND

Expansion joints are intentionally provided gaps in adjacent structures, such as concrete structures, that are design to accommodate movement caused by thermal expansion, seismic cycling, vibration, and other similar structural forces. These joints may prevent cracking and structural damage by allowing adjacent building members to expand and contract freely. However, for safety, aesthetics, and structural integrity, these expansion joints often utilize a protective cover assembly that spans the gap formed by the expansion joints while permitting controlled movement of the underlying structures.

Traditional cover assemblies used in connection with expansion joints may implement centering bars that align and support a cover plate of the cover assembly while still allowing for horizontal and/or vertical movement of the underlying structures. To secure the centering bar to the cover plate, traditional cover assemblies may utilize bolts that pass through pre-drilled apertures in each of the centering bar and the cover plate. However, the attachment method described herein presents challenges in manufacturing, assembly, and long term performance.

For example, traditional cover assemblies that utilize a centering bar and cover plate may be difficult to install, particularly in low-visibility environments and when working with heavy materials. Furthermore, the pre-drilled apertures may limit tolerance for movement of the underlying structure, which may result in misalignment, excessive wear, and/or failure of the cover assembly over time.

Accordingly, a need exists for a cover plate assembly that resolves the shortcomings of traditional assemblies by providing a cover plate and expansion joint centering bar that are cost-effective, easily installed, and highly durable.

SUMMARY

In embodiments of the present disclosure, a cover plate assembly is disclosed. The cover plate assembly includes a first track of a first base plate that is affixed to a first structural member and a second track of a second base plate that is affixed to a second structural member. The cover plate assembly further includes a centering bar slidably engaged with the first track of the first base plate and the second track of the second base plate, and having a centering bar opening that receives a fastener. A guide is coupled to the centering bar and aligns the fastener with the centering bar opening, and a cover plate having a cover plate aperture aligns with the guide and the centering bar opening. A spring assembly is attached to the centering bar and receives the fastener after the fastener is inserted through the cover plate aperture and the centering bar opening.

In other embodiments, a cover plate assembly is disclosed. The cover plate assembly includes a centering bar including upper cavity defining an upper slit and a lower cavity defining a lower slit, a centering bar opening formed in a central portion of the upper cavity of the centering bar, a cover plate, a guide, and a spring having a flange positioned on an end of the spring, the spring being detachably coupled to the lower cavity of the centering bar via the flange. The guide is detachably secured within the centering bar opening to align the cover plate, the centering bar, and the spring.

In yet another embodiment, a cover plate assembly is disclosed. The cover plate assembly includes a cover plate including a cover plate aperture formed through the cover plate, a centering bar including a centering bar opening formed through the centering bar, a fastener, and a guide detachably attached to the centering bar between the cover plate aperture and the centering bar opening. The guide aligns the fastener with the cover plate aperture and the centering bar opening such that the fastener is insertable through the cover plate aperture and the centering bar opening to couple the cover plate to the centering bar.

Elements in the figures are shown for simplicity and clarity and are not necessarily drawn to exact scale. It can be understood that these accompanying drawings are not only intended to explain and illustrate the present disclosure and description, but also contribute to the scope of the present disclosure.

DETAILED DESCRIPTION

The implementation and application of embodiments of a cover assembly will be discussed in detail below. The cover assembly may include a first track of a first base plate that is affixed to a first structural member and a second track of a second base plate that is affixed to a second structural member. The cover plate assembly may further a centering bar slidably engaged with the first track of the first base plate and the second track of the second base plate, and having a centering bar opening that receives a fastener. A guide is coupled to the centering bar and aligns the fastener with the centering bar opening, and a cover plate having a cover plate aperture aligns with the guide and the centering bar opening. A spring assembly is attached to the centering bar and receives the fastener after the fastener is inserted through the cover plate aperture and the centering bar opening. In these embodiments, the guide may aid in reducing alignment issues during installation, thereby improving ease and efficiency of the overall installation process.

As provided herein, it should be appreciated that the terms “disclosure”, “present disclosure” and variations thereof are not intended to mean every possible embodiment encompassed by this disclosure. Thus, the subject matter of each such reference should not be considered as necessary for, or part of, every embodiment hereof because of such reference.

The term “coupled” and the like, and variations thereof, is intended to mean either an indirect or direct connection or engagement. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices and connections.

Certain terms are used herein to refer to particular components. However, it should be understood that different persons may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function.

Furthermore, the terms “including” and “comprising” are used herein in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.”

Further, reference herein to components and aspects in a singular tense does not necessarily limit the present disclosure to only one such component or aspect, but should be interpreted generally to mean one or more, as may be suitable and desirable in each particular instance.

Preferred embodiments of the present disclosure are well adapted to carry out one or more of the objects of this disclosure. However, the present disclosure does not require each of the components and acts described above and are in no way limited to the above-described embodiments. Any one or more of the above components, features and processes may be employed in any suitable configuration without inclusion of other such components, features and processes. Moreover, the present disclosure includes additional features, capabilities, functions, uses and applications that have not been specifically addressed herein but are, or will become, apparent from the description herein

As noted hereinabove, traditional expansion joint cover assemblies incorporate centering bars that are secured to a cover plate of the assembly by placing a bolt, or other similar fastener, through pre-fabricated openings formed in each of the centering bar and cover plate. However, aligning the bolt with the pre-fabricated openings in the cover plate and centering bar is often challenging, which may cause installation challenges to users.

Furthermore, the rigid fastening mechanisms (e.g., bolts, etc.) used to fasten the centering bar to the cover plate of traditional cover assemblies may not be capable of compensating for three-dimensional movement of the underlying structures. Accordingly, movement of the underlying structures may result in misalignment, wear, and/or failure of the cover plate assembly over time.

Moreover, expansion joints are manufactured in a variety of sizes, which necessitates the use of centering bars having different lengths. In traditional expansion joint cover assemblies, the variety of expansion joints may result in the need for multiple centering bars, which may increase production complexity, tooling costs, and material waste.

The cover plate assembly and centering bar described herein aim to address these shortcomings by providing a centering bar that includes a guide configured to direct a fastener (e.g., bolt, screw, etc.) into an aperture formed in the centering bar. As will be described in additional detail herein, the guide may aid in reducing alignment issues during installation, thereby improvement case and efficiency of the overall installation process.

Furthermore, the centering bar of the cover plate assembly described herein may include a plurality of cavities that may be configured to facilitate the attachment of extension components. Accordingly, a user may adjust a length of the centering bar via the extension components, which may clement the need for multiple tooling configurations. The manufacturing of the plurality of cavities and the centering bar may also allow for enhanced durability and versatility of the cover plate assembly, as will be described in additional detail herein.

The present disclosure will now be described more fully with reference to the accompanying drawings, in which some preferred embodiments of the disclosure are shown. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Like numbers refer to like elements throughout.

Referring now to FIG. 1, a cover plate assembly 1000 is illustrated. The cover plate assembly 1000 may be positioned between expansion gap 4000, which may be formed between a first structural member 2000 and a second structural member 3000. In the embodiments described herein, it should be appreciated that the first and second structural members 2000, 3000 may be concrete structural members, such as concrete floor structural members, or any other similar structural member in which an expansion gap may be formed.

Referring still to FIG. 1, the cover assembly 1000 may further include a first base plate 100 and a second base plate 101, which may be configured to be coupled to the first structural member 2000 and the second structural member 3000, respectively. In these embodiments, the first base plate 100 may include a first track 110, such as a curved concave track, that extends into the expansion gap 4000 and couples the first base plate 100 to the first structural member 2000. Similarly, the second base plate 101 may include a second track 111, such as a curved concave track, that extends into the expansion gap 4000 and couples the second base plate 101 to the second structural member 3000.

As further illustrated in FIG. 1, the first base plate 100 and the second base plate 101 may be attached to their respective structural members (e.g., first and second structural members 2000, 3000) using mechanical fasteners 150, such as anchors, bolts, nails, rivets, screws, tacks, or any other similar mechanical fastener. Although FIG. 1 depicts the first base plate 100 and the second base plate 101 as being coupled to the first structural member 2000 and the second structural member 3000 using mechanical fasteners, it should be further appreciated that, in some embodiments, the first and second base plates 100, 101 may be coupled to the first and second structural members with elastomeric concrete or any other similar attachment means without departing from the scope of the present disclosure.

In some embodiments, it should be further appreciated that each of the first base plate 100 and/or the second base plate 101 may include a plurality of alignment slots. The plurality of alignment slots may aid in ensuring that a centering bar of the cover plate assembly 1000 is aligned with the first and second structural members 2000, 3000, as will be described in additional detail herein.

Referring still to FIG. 1, the cover assembly 1000 may further include a centering bar 300, which may be secured to the first plate 100 and the second base plate 101, respectively. In some embodiments, the centering bar 300 may be directly secured (e.g., fastened or otherwise) to the first plate 100 and the second base plate 101. However, in other embodiments, such as the embodiment depicted in FIG. 1, the cover assembly 1000 may further include a plurality of extension member that are used to secure the centering bar 300 to each of the first base plate 100 and the second base plate 101. It should be appreciated that the plurality of extension members may be implemented in embodiments in a centering bar length of the centering bar is less than an expansion gap length of the expansion gap, as will be described in additional detail herein.

Referring still to FIG. 1, the centering bar 300 may be detachably and/or releasbly coupled to each of the plurality of extension members. For example, as depicted in FIG. 1, the plurality of extension members may include a first extension member 400 and a second extension member 401 coupled to the centering bar 300. In these embodiments, each of the first extension member 400 and the second extension member 401 may include a distal end that is a spherically shaped end, For example, the first extension member 400 may include a first spherically shaped end 450 while the second extension member 401 may include a second spherically shaped end 451.

In the embodiments depicted in FIG. 1, the first and second spherically shaped ends 450, 451 may be proportioned (e.g., sized and/or shaped) such that the first and second spherically shaped ends 450, 451 are engageable with the curved concave tracks 110 and 111 formed in the first base plate 100 and second base plate 101, respectively. For example, in these embodiments, the first and second spherically shaped ends 450, 451 may be slidably engageable with the first base plate 100 and the second base plate 101, such that the first and second spherically shaped ends 450, 451 may slide relative the first track 110 of the first base plate 100 and the second track 11 of the second base plate 101 in both a horizontal and a vertical direction (e.g., in the +/−x and/or +/−y-direction as depicted in the coordinate axis of FIG. 1).

Referring still to FIG. 1, the first extension member 400 and the second extension member 401 may each further include a proximal end (e.g., an end positioned opposite the first and second spherically shaped ends 450, 451, respectively) that may be attached to an end of the centering bar 300 such that, when the first extension member 400 and the second extension member 401 are secured to the centering bar, the first extension member 400, the second extension member 401, and the centering bar 300 have a combined length that is fixed.

In operation, and as described hereinabove, the first and second structural components 2000, 3000 may be subjected to forces (e.g., expansion and contraction forces, seismic events, mechanical vibrations, etc.) that may cause the first and second structural components 2000, 3000 to shift, thereby adjusting the expansion gap length of the expansion gap. For example, during contraction of the expansion gap 4000, a distance between the first and second spherically shaped ends 450, 451 of the first extension member 400 and the second extension member 401 may decrease in a longitudinal direction (e.g., in the +/−x-direction as depicted in the coordinate axis of FIG. 1) as the first and second spherically shaped ends 450, 451 slide or rotate along the curved concave surfaces of the first track 110 and the second track 111 of the first base plate 100 and the second base plate 101, respectively.

It should be appreciated that, in these embodiments, equilibrium of the cover plate assembly 1000 may be maintained by increasing the distance between the first and second spherically shaped ends 450, 451 in either a transverse direction (e.g., the +/−z-direction as depicted in the coordinate axis of FIG. 1), a vertical direction (e.g., the +/−y-direction as depicted in the coordinate axis of FIG. 1), or both directions, such that the cover plate assembly 1000 is capable of accommodating adjustments in the expansion gap length of the expansion gap 4000 without altering the centering bar length of the centering bar 300.

Similarly, during expansion of the expansion gap 4000, the distance between the first and second spherically shaped ends 450, 451 may increase in the longitudinal direction, and equilibrium of the cover plate assembly 1000 may be maintained by decreasing the distance between the first and second spherically shaped ends 450,451 in either the transverse direction, the vertical direction, or both, such that the cover plate assembly 1000 is capable of accommodating adjustments in the expansion gap length of the expansion gap 4000 without altering the centering bar length of the centering bar 300.

As further illustrated in FIG. 1, the cover plate assembly 1000 may further include a cover plate 200 that extends across the expansion gap 4000 and a centering bar assembly 1300 (e.g., the centering bar 300 and the plurality of extension members). In these embodiments, the cover plate 200 is coupled to the centering bar 300 using a fastener 50, such as a bolt, screw, or any other similar fastening mechanism. As shown in FIG. 1, the fastener 50 may extend through an aperture formed in the cover plate 200 and through a centering bar opening 380 formed in centering bar 300, such that the fastener may be received within a spring assembly 500, as will be described in additional detail with reference to FIGS. 2-4(d).

Referring still to FIG. 1, the cover plate assembly 1000 may further include a guide 600, such as a hollow guide, that may be detachably and/or releasbly coupled to a top surface of the centering bar 300 and aligned with the centering bar opening 380. In these embodiments, the guide 600 may allow for easier alignment of the fastener 50 with a central portion of the cover plate 200 and the centering bar opening 380. 380 It should be appreciated that, in the embodiments described herein, the guide 600 may have a conical shape, or any other shape configured to aid in aligning the various components of the cover plate assembly 1000 described herein. For example, in embodiments in which the guide 600 includes a hollow, conical shape, a centering bar opening 380 interior section of the guide 600 may guide the fastener 50 into the centering bar opening 380 even if the fastener 50 is initially inserted off center of the centering bar opening 380.

In the embodiments described herein, it should be appreciated that the various components of the cover plate assembly 1000 may be strong enough to withstand forces from applied above and/or across the cover plate assembly 1000 (e.g., traffic passing over a concrete road in which the cover plate assembly 1000 is used) and expansion and/or contraction forces (e.g. seismic forces) that impact the expansion gap length of the expansion gap, as has been described in detail herein. Accordingly, in these embodiments, suitable materials that may be used to manufacture the various components of the assembly may include metals, metal alloys and polymers, or any other similar materials without departing from the scope of the present disclosure.

More particularly, in some embodiments, the cover plate 200 may be formed of aluminum, stainless steel, carbon steel, bronze plate or aluminum extrusion. Similarly, the centering bar 300 may be formed of an aluminum extrusion, and the plurality of extension members may be fabricated from aluminum or carbon steel. Furthermore, the base members (e.g., first base plate 100 and second base plate 101) may also be formed of aluminum extrusion. In these embodiments, the first and second spherically shaped ends of the extension members may be formed of a thermoplastic elastomer and may be attached to the extension members using roll pins, while the guide may be formed of a polyethylene plastic. As noted hereinabove, it should be appreciated that the various materials described herein are for exemplary purposes only, and the various components of the cover plate assembly 1000 may each be formed of any material without departing from the scope of the present disclosure.

Turning now to FIGS. 2-3(b), the centering bar assembly 1300 is depicted in additional detail. In these embodiments, as illustrated in FIG. 2, the centering bar 300 may include an upper cavity 330 that is sized and shaped to allow the proximal ends of the first extension member 400 and the second extension member 401, respectively to be inserted into the upper cavity 330.

Referring still to FIGS. 2-3(b), the first extension member 400 and the second extension member 401 may each have an aperture that is aligned with at least one of centering bar apertures 320, 321 formed in the centering bar 300. For example, the first extension member 400 may include a first extension member aperture 420 which is aligned with a first centering bar aperture 320 of the centering bar 300, while the second extension member 401 may include a second extension member aperture 421 which is aligned with a second centering bar aperture 321 formed in the centering bar 300. the centering bar aperture In these embodiments the first and second extension member apertures 420, 421 and the first and second centering bar apertures 320, 321 may be aligned during manufacturing using fasteners (e.g. screws or bolts) 60 and washers 61.

Referring still to FIGS. 2-3(b), the upper cavity 330 of the centering bar 300 may further include an elongated slit 350 that extends across the centering bar length of the centering bar 300 from a first end of the centering bar 300 to a second end of centering bar 300. In these embodiments, a central portion of the elongated slit 350 may be enlarged to form an opening 390. As illustrated in FIG. 2, the opening 390 may allow the guide 600 to be inserted into the top of centering bar 300 and fit (e.g., friction fit or otherwise) into place in alignment with the centering bar opening 380.

In the embodiments depicted in FIGS. 2-3(b), the centering bar 300 may further include a lower cavity 340 that is sized and shaped to slidably accept a flange 540 of the spring assembly 500. For example, prior to the first extension member 400 and the second extension member 401 being attached to centering bar 300, the spring assembly 500 may be moved (e.g., slid or otherwise) into the lower cavity 340 and moved into position under the centering bar opening 380 such that the fastener 50 can be inserted into the spring assembly 500 and threaded into a socket 550 formed at a bottom portion of the spring assembly 500.

In the embodiments described herein, it should be understood that the spring assembly 500 may enhance the engagement of the fastener 50 and the centering bar 300, while also offering vibration resistance and accommodating movement within the expansion gap 4000. For example, the spring assembly 500 may provide a preloaded force on the fastener 50 when the fastener is inserted into the socket 550, which may aid in ensuring that the fastener 50 remains secured within the socket 550. Furthermore, the spring assembly 500 may act to absorb dynamic forces acting on the cover plate assembly 1000 and/or the first and second structural elements 2000, 3000. For example, the spring assembly 500 may absorb shocks and/or other vibrations that may otherwise gradually loosen the fastener 50 from the socket 550 over time.

It should be appreciated that the upper and lower cavities 330, 340 may allow for the easy attachment of the first and second extension members 400, 401, the guide 600, and the spring assembly 500. Furthermore, in some embodiments, the upper and lower cavities 330, 340 may further include housings, notches, passages, recesses, slots, tracks, rails, grooves, or any other similar features which may enable the first and second extension members 400, 401, the guide 600, and the spring assembly 500 to be inserted into and secured within the centering bar 300.

Referring now to FIGS. 2-4(d), the guide 600 is depicted in additional detail. For example, in the embodiments described herein, the guide 600 may further include an enlarged guide opening 610 that tapers (e.g., funnels down to) into a conduit 620, such that the conduit 620 has a narrower profile relative the enlarged guide opening 610. In these embodiments, the guide 600 may also include a plurality of extensions 650 that allow the guide 600 to be inserted into an enlarged centering bar opening 390, such that the conduit 620 of the guide is received within the centering bar opening 680. Once the guide 600 is positioned within the centering bar 300 as described herein, the guide 600 may be rotated (e.g., 90 degrees or any other similar degree of rotation) such that the guide 600 may be secured within the upper cavity 330 of the centering bar 300 via a friction and/or interference fit. As depicted most clearly in FIGS. 4(a) and 4(b), the guide 600 may have a generally hexagonal profile that allows for use of wrenches or adaptive tools as assistive devices in order to rotate guide 600 into place, thereby reducing risk of repetitive stress injury by assemblers.

Referring now to FIGS. 1-4(d), assembly of the cover plate assembly 1000 will be described. For example, in operation, when the centering bar assembly 1300 is placed in the expansion gap 4000, the guide 600 may allow for easier insertion of the fastener 50 through the cover plate 200 and into the centering bar 300 and the spring assembly 500. In the embodiments described herein, the guide 600 may also have a color and/or finish that cases the ability of a user to see through the cover plate aperture. For example, in some embodiments, the guide may be formed of a translucent and/or transparent material.

As provided herein, it should be appreciated that the disclosed centering bar assembly 1300 may lower material costs and assembly costs of the cover plate assembly 1000. For example, extruding long sections of the centering bar 300 allows for the centering bar to easily be cut to desired lengths, rather than requiring different tooling and manufacturing for various centering bars 300 having different center bar lengths. Accordingly, once a desired centering bar length is determined, After determining a desired length of the centering bar 300, the centering bar assembly 1300 may be formed simply by forming the centering bar opening 680 and the centering bar apertures 320, 321 in the centering bar 300 and then attaching the centering bar 300 to the first and second extension members 400, 401, the guide 600, and the spring assembly 500. It should be further appreciated that the centering bar 300 described herein may also allow for savings in material costs as the extruded shapes with hollow cavities that form the centering bar 300 may provide structural strength but require but require less material than traditional centering bars.

Turning now to FIGS. 5-7(b), another embodiment of the cover plate assembly 1000 is illustrated. The cover plate assembly 1000 is structurally similar to that depicted in FIGS. 1-4(d), such that like references will be used to refer to like structure where possible.

As illustrated in FIGS. 5-7(b), in some embodiments, the cover plate assembly 1000 may be formed without the spring assembly 500. In these embodiments, removal of the spring assembly may aid in minimizing costs, simplifying installation, and increasing durability of the cover plate assembly 1000. For example, elimination of the spring assembly 500 may allow the cover plate assembly 1000 to be formed with fewer components, thereby reducing material and production costs.

As illustrated most clearly in FIG. 5, in these embodiments, the cover plate assembly 1000 may utilize a locking nut 700 to secure the fastener 50 and couple the cover plate 200 to the centering bar 300. As illustrated in FIG. 5, as the fastener 50 extends through the locking nut 700, the fastener 50 may also form a friction and/or interference fit with the centering bar 300 to further aid in securing the fastener 50 in a desired position.

It should be appreciated that the removal of the spring assembly 500 may, in some embodiments, enhance the durability of the cover plate assembly 1000. For example, in applications in which long term durability is desired, providing a rigid, spring-less cover plate assembly may minimize potential failure points in the cover plate assembly 1000. These embodiments may be particularly suitable to low-movement environments, in which dynamic forces on the expansion gap are minimal, as the flexibility afforded by the spring assembly 500 may not be needed. Accordingly, it should be appreciated that the spring assembly 500 may be optionally included in the cover plate assembly 1000, as may be determined as a product of the environment in which the cover plate assembly 1000 is employed.

While the cover plate assembly has been described in connection with certain illustrative embodiments, as shown in the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiments for performing the same function without deviating therefrom. Furthermore, the various illustrative embodiments may be combined to produce the desired results. Therefore, the cover plate assembly should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.

In view of the foregoing, it should be appreciated that a cover assembly is described herein. The cover assembly may include a first track of a first base plate that is affixed to a first structural member and a second track of a second base plate that is affixed to a second structural member. The cover plate assembly may further a centering bar slidably engaged with the first track of the first base plate and the second track of the second base plate, and having a centering bar opening that receives a fastener. A guide is coupled to the centering bar and aligns the fastener with the centering bar opening, and a cover plate having a cover plate aperture aligns with the guide and the centering bar opening. A spring assembly is attached to the centering bar and receives the fastener after the fastener is inserted through the cover plate aperture and the centering bar opening. In these embodiments, the guide may aid in reducing alignment issues during installation, thereby improving case and efficiency of the overall installation process.

Many different arrangements of the various components depicted, as well as components not shown, are possible without departing from the scope of the present disclosure. Embodiments of the technology have been described with the intent to be illustrative rather than restrictive.

Alternative embodiments and alternative means of implementing the aforementioned may be completed without departing from the scope of the present disclosure. Certain features and sub-combinations may be employed without reference to other features and sub-combinations and are contemplated within the scope of the disclosure.

It should be understood that the embodiments as shown in the drawings only show the optional shapes, sizes and arrangements of optional components of the trampoline according to the present disclosure, which are merely illustrative but not restrictive, and other shapes, sizes and arrangements may be employed without departing from the idea and scope of the present disclosure.

The technical contents and technical features of the present disclosure are disclosed above, but it can be understood that various variations and improvements to the concepts disclosed above, and all the variations and improvements fall into the scope of protection of the present disclosure. The descriptions of the above embodiments are illustrative but not restrictive, and the scope of protection of the present disclosure is determined by the claims.